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       /*
        * QEMU System Emulator block driver
+       *
        * Copyright (c) 2003 Fabrice Bellard
+       *
        * Permission is hereby granted, free of charge, to any person obtaining a copy
        * of this software and associated documentation files (the "Software"), to deal
        * in the Software without restriction, including without limitation the rights
        * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
        * copies of the Software, and to permit persons to whom the Software is
        * furnished to do so, subject to the following conditions:
+       *
        * The above copyright notice and this permission notice shall be included in
        * all copies or substantial portions of the Software.
+       *
        * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
        * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
        * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
        * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
        * THE SOFTWARE.
        */
       #include "config-host.h"
       #include "qemu-common.h"
       #include "trace.h"
       #include "monitor/monitor.h"
       #include "block/block_int.h"
       #include "block/blockjob.h"
       #include "qemu/module.h"
       #include "qapi/qmp/qjson.h"
       #include "sysemu/sysemu.h"
       #include "qemu/notify.h"
       #include "block/coroutine.h"
       #include "block/qapi.h"
       #include "qmp-commands.h"
       #include "qemu/timer.h"
       #ifdef CONFIG_BSD
       #include <sys/types.h>
       #include <sys/stat.h>
       #include <sys/ioctl.h>
       #include <sys/queue.h>
       #ifndef __DragonFly__
       #include <sys/disk.h>
       #endif
       #endif
       #ifdef _WIN32
       #include <windows.h>
       #endif
       struct BdrvDirtyBitmap {
           HBitmap *bitmap;
           QLIST_ENTRY(BdrvDirtyBitmap) list;
       };
       #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
       static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
       static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
               int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
               BlockDriverCompletionFunc *cb, void *opaque);
       static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
               int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
               BlockDriverCompletionFunc *cb, void *opaque);
       static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
                                                int64_t sector_num, int nb_sectors,
                                                QEMUIOVector *iov);
       static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
                                                int64_t sector_num, int nb_sectors,
                                                QEMUIOVector *iov);
       static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
           int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
           BdrvRequestFlags flags);
       static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
           int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
           BdrvRequestFlags flags);
       static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
                                                      int64_t sector_num,
                                                      QEMUIOVector *qiov,
                                                      int nb_sectors,
                                                      BdrvRequestFlags flags,
                                                      BlockDriverCompletionFunc *cb,
                                                      void *opaque,
                                                      bool is_write);
       static void coroutine_fn bdrv_co_do_rw(void *opaque);
       static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
           int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
       static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
           QTAILQ_HEAD_INITIALIZER(bdrv_states);
       static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
           QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
       static QLIST_HEAD(, BlockDriver) bdrv_drivers =
           QLIST_HEAD_INITIALIZER(bdrv_drivers);
       /* If non-zero, use only whitelisted block drivers */
       static int use_bdrv_whitelist;
       #ifdef _WIN32
       static int is_windows_drive_prefix(const char *filename)
+      {
           return (((filename[0] >= 'a' && filename[0] <= 'z') ||
                    (filename[0] >= 'A' && filename[0] <= 'Z')) &&
                   filename[1] == ':');
+      }
       int is_windows_drive(const char *filename)
+      {
           if (is_windows_drive_prefix(filename) &&
               filename[2] == '\0')
               return 1;
           if (strstart(filename, "\\\\.\\", NULL) ||
               strstart(filename, "//./", NULL))
               return 1;
           return 0;
+      }
       #endif
       /* throttling disk I/O limits */
       void bdrv_set_io_limits(BlockDriverState *bs,
                               ThrottleConfig *cfg)
+      {
           int i;
           throttle_config(&bs->throttle_state, cfg);
           for (i = 0; i < 2; i++) {
               qemu_co_enter_next(&bs->throttled_reqs[i]);
+          }
+      }
       /* this function drain all the throttled IOs */
       static bool bdrv_start_throttled_reqs(BlockDriverState *bs)
+      {
           bool drained = false;
           bool enabled = bs->io_limits_enabled;
           int i;
           bs->io_limits_enabled = false;
           for (i = 0; i < 2; i++) {
               while (qemu_co_enter_next(&bs->throttled_reqs[i])) {
                   drained = true;
+              }
+          }
           bs->io_limits_enabled = enabled;
           return drained;
+      }
       void bdrv_io_limits_disable(BlockDriverState *bs)
+      {
           bs->io_limits_enabled = false;
           bdrv_start_throttled_reqs(bs);
           throttle_destroy(&bs->throttle_state);
+      }
       static void bdrv_throttle_read_timer_cb(void *opaque)
+      {
           BlockDriverState *bs = opaque;
           qemu_co_enter_next(&bs->throttled_reqs[0]);
+      }
       static void bdrv_throttle_write_timer_cb(void *opaque)
+      {
           BlockDriverState *bs = opaque;
           qemu_co_enter_next(&bs->throttled_reqs[1]);
+      }
       /* should be called before bdrv_set_io_limits if a limit is set */
       void bdrv_io_limits_enable(BlockDriverState *bs)
+      {
           assert(!bs->io_limits_enabled);
           throttle_init(&bs->throttle_state,
                         QEMU_CLOCK_VIRTUAL,
                         bdrv_throttle_read_timer_cb,
                         bdrv_throttle_write_timer_cb,
                         bs);
           bs->io_limits_enabled = true;
+      }
       /* This function makes an IO wait if needed
+       *
        * @nb_sectors: the number of sectors of the IO
        * @is_write:   is the IO a write
        */
       static void bdrv_io_limits_intercept(BlockDriverState *bs,
                                            int nb_sectors,
                                            bool is_write)
+      {
           /* does this io must wait */
           bool must_wait = throttle_schedule_timer(&bs->throttle_state, is_write);
           /* if must wait or any request of this type throttled queue the IO */
           if (must_wait ||
               !qemu_co_queue_empty(&bs->throttled_reqs[is_write])) {
               qemu_co_queue_wait(&bs->throttled_reqs[is_write]);
+          }
           /* the IO will be executed, do the accounting */
           throttle_account(&bs->throttle_state,
                            is_write,
                            nb_sectors * BDRV_SECTOR_SIZE);
           /* if the next request must wait -> do nothing */
           if (throttle_schedule_timer(&bs->throttle_state, is_write)) {
               return;
+          }
           /* else queue next request for execution */
           qemu_co_queue_next(&bs->throttled_reqs[is_write]);
+      }
       size_t bdrv_opt_mem_align(BlockDriverState *bs)
+      {
           if (!bs || !bs->drv) {
               /* 4k should be on the safe side */
               return 4096;
+          }
           return bs->bl.opt_mem_alignment;
+      }
       /* check if the path starts with "<protocol>:" */
       static int path_has_protocol(const char *path)
+      {
           const char *p;
       #ifdef _WIN32
           if (is_windows_drive(path) ||
               is_windows_drive_prefix(path)) {
               return 0;
+          }
           p = path + strcspn(path, ":/\\");
       #else
           p = path + strcspn(path, ":/");
       #endif
           return *p == ':';
+      }
       int path_is_absolute(const char *path)
+      {
       #ifdef _WIN32
           /* specific case for names like: "\\.\d:" */
           if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
               return 1;
+          }
           return (*path == '/' || *path == '\\');
       #else
           return (*path == '/');
       #endif
+      }
       /* if filename is absolute, just copy it to dest. Otherwise, build a
          path to it by considering it is relative to base_path. URL are
          supported. */
       void path_combine(char *dest, int dest_size,
                         const char *base_path,
                         const char *filename)
+      {
           const char *p, *p1;
           int len;
           if (dest_size <= 0)
               return;
           if (path_is_absolute(filename)) {
               pstrcpy(dest, dest_size, filename);
           } else {
               p = strchr(base_path, ':');
               if (p)
                   p++;
               else
                   p = base_path;
               p1 = strrchr(base_path, '/');
       #ifdef _WIN32
+              {
                   const char *p2;
                   p2 = strrchr(base_path, '\\');
                   if (!p1 || p2 > p1)
                       p1 = p2;
+              }
       #endif
               if (p1)
                   p1++;
               else
                   p1 = base_path;
               if (p1 > p)
                   p = p1;
               len = p - base_path;
               if (len > dest_size - 1)
                   len = dest_size - 1;
               memcpy(dest, base_path, len);
               dest[len] = '\0';
               pstrcat(dest, dest_size, filename);
+          }
+      }
       void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz)
+      {
           if (bs->backing_file[0] == '\0' || path_has_protocol(bs->backing_file)) {
               pstrcpy(dest, sz, bs->backing_file);
           } else {
               path_combine(dest, sz, bs->filename, bs->backing_file);
+          }
+      }
       void bdrv_register(BlockDriver *bdrv)
+      {
           /* Block drivers without coroutine functions need emulation */
           if (!bdrv->bdrv_co_readv) {
               bdrv->bdrv_co_readv = bdrv_co_readv_em;
               bdrv->bdrv_co_writev = bdrv_co_writev_em;
               /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
                * the block driver lacks aio we need to emulate that too.
                */
               if (!bdrv->bdrv_aio_readv) {
                   /* add AIO emulation layer */
                   bdrv->bdrv_aio_readv = bdrv_aio_readv_em;
                   bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
+              }
+          }
           QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
+      }
       /* create a new block device (by default it is empty) */
       BlockDriverState *bdrv_new(const char *device_name)
+      {
           BlockDriverState *bs;
           bs = g_malloc0(sizeof(BlockDriverState));
           QLIST_INIT(&bs->dirty_bitmaps);
           pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
           if (device_name[0] != '\0') {
               QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list);
+          }
           bdrv_iostatus_disable(bs);
           notifier_list_init(&bs->close_notifiers);
           notifier_with_return_list_init(&bs->before_write_notifiers);
           qemu_co_queue_init(&bs->throttled_reqs[0]);
           qemu_co_queue_init(&bs->throttled_reqs[1]);
           bs->refcnt = 1;
           return bs;
+      }
       void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify)
+      {
           notifier_list_add(&bs->close_notifiers, notify);
+      }
       BlockDriver *bdrv_find_format(const char *format_name)
+      {
           BlockDriver *drv1;
           QLIST_FOREACH(drv1, &bdrv_drivers, list) {
               if (!strcmp(drv1->format_name, format_name)) {
                   return drv1;
+              }
+          }
           return NULL;
+      }
       static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
+      {
           static const char *whitelist_rw[] = {
               CONFIG_BDRV_RW_WHITELIST
           };
           static const char *whitelist_ro[] = {
               CONFIG_BDRV_RO_WHITELIST
           };
           const char **p;
           if (!whitelist_rw[0] && !whitelist_ro[0]) {
               return 1;               /* no whitelist, anything goes */
+          }
           for (p = whitelist_rw; *p; p++) {
               if (!strcmp(drv->format_name, *p)) {
                   return 1;
+              }
+          }
           if (read_only) {
               for (p = whitelist_ro; *p; p++) {
                   if (!strcmp(drv->format_name, *p)) {
                       return 1;
+                  }
+              }
+          }
           return 0;
+      }
       BlockDriver *bdrv_find_whitelisted_format(const char *format_name,
                                                 bool read_only)
+      {
           BlockDriver *drv = bdrv_find_format(format_name);
           return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL;
+      }
       typedef struct CreateCo {
           BlockDriver *drv;
           char *filename;
           QEMUOptionParameter *options;
           int ret;
           Error *err;
       } CreateCo;
       static void coroutine_fn bdrv_create_co_entry(void *opaque)
+      {
           Error *local_err = NULL;
           int ret;
           CreateCo *cco = opaque;
           assert(cco->drv);
           ret = cco->drv->bdrv_create(cco->filename, cco->options, &local_err);
           if (error_is_set(&local_err)) {
               error_propagate(&cco->err, local_err);
+          }
           cco->ret = ret;
+      }
       int bdrv_create(BlockDriver *drv, const char* filename,
           QEMUOptionParameter *options, Error **errp)
+      {
           int ret;
           Coroutine *co;
           CreateCo cco = {
               .drv = drv,
               .filename = g_strdup(filename),
               .options = options,
               .ret = NOT_DONE,
               .err = NULL,
           };
           if (!drv->bdrv_create) {
               error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
               ret = -ENOTSUP;
               goto out;
+          }
           if (qemu_in_coroutine()) {
               /* Fast-path if already in coroutine context */
               bdrv_create_co_entry(&cco);
           } else {
               co = qemu_coroutine_create(bdrv_create_co_entry);
               qemu_coroutine_enter(co, &cco);
               while (cco.ret == NOT_DONE) {
                   qemu_aio_wait();
+              }
+          }
           ret = cco.ret;
           if (ret < 0) {
               if (error_is_set(&cco.err)) {
                   error_propagate(errp, cco.err);
               } else {
                   error_setg_errno(errp, -ret, "Could not create image");
+              }
+          }
       out:
           g_free(cco.filename);
           return ret;
+      }
       int bdrv_create_file(const char* filename, QEMUOptionParameter *options,
                            Error **errp)
+      {
           BlockDriver *drv;
           Error *local_err = NULL;
           int ret;
           drv = bdrv_find_protocol(filename, true);
           if (drv == NULL) {
               error_setg(errp, "Could not find protocol for file '%s'", filename);
               return -ENOENT;
+          }
           ret = bdrv_create(drv, filename, options, &local_err);
           if (error_is_set(&local_err)) {
               error_propagate(errp, local_err);
+          }
           return ret;
+      }
       int bdrv_refresh_limits(BlockDriverState *bs)
+      {
           BlockDriver *drv = bs->drv;
           memset(&bs->bl, 0, sizeof(bs->bl));
           if (!drv) {
               return 0;
+          }
           /* Take some limits from the children as a default */
           if (bs->file) {
               bdrv_refresh_limits(bs->file);
               bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length;
               bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment;
           } else {
               bs->bl.opt_mem_alignment = 512;
+          }
           if (bs->backing_hd) {
               bdrv_refresh_limits(bs->backing_hd);
               bs->bl.opt_transfer_length =
                   MAX(bs->bl.opt_transfer_length,
                       bs->backing_hd->bl.opt_transfer_length);
               bs->bl.opt_mem_alignment =
                   MAX(bs->bl.opt_mem_alignment,
                       bs->backing_hd->bl.opt_mem_alignment);
+          }
           /* Then let the driver override it */
           if (drv->bdrv_refresh_limits) {
               return drv->bdrv_refresh_limits(bs);
+          }
           return 0;
+      }
       /*
        * Create a uniquely-named empty temporary file.
        * Return 0 upon success, otherwise a negative errno value.
        */
       int get_tmp_filename(char *filename, int size)
+      {
       #ifdef _WIN32
           char temp_dir[MAX_PATH];
           /* GetTempFileName requires that its output buffer (4th param)
              have length MAX_PATH or greater.  */
           assert(size >= MAX_PATH);
           return (GetTempPath(MAX_PATH, temp_dir)
                   && GetTempFileName(temp_dir, "qem", 0, filename)
                   ? 0 : -GetLastError());
       #else
           int fd;
           const char *tmpdir;
           tmpdir = getenv("TMPDIR");
           if (!tmpdir)
               tmpdir = "/tmp";
           if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
               return -EOVERFLOW;
+          }
           fd = mkstemp(filename);
           if (fd < 0) {
               return -errno;
+          }
           if (close(fd) != 0) {
               unlink(filename);
               return -errno;
+          }
           return 0;
       #endif
+      }
       /*
        * Detect host devices. By convention, /dev/cdrom[N] is always
        * recognized as a host CDROM.
        */
       static BlockDriver *find_hdev_driver(const char *filename)
+      {
           int score_max = 0, score;
           BlockDriver *drv = NULL, *d;
           QLIST_FOREACH(d, &bdrv_drivers, list) {
               if (d->bdrv_probe_device) {
                   score = d->bdrv_probe_device(filename);
                   if (score > score_max) {
                       score_max = score;
                       drv = d;
+                  }
+              }
+          }
           return drv;
+      }
       BlockDriver *bdrv_find_protocol(const char *filename,
                                       bool allow_protocol_prefix)
+      {
           BlockDriver *drv1;
           char protocol[128];
           int len;
           const char *p;
           /* TODO Drivers without bdrv_file_open must be specified explicitly */
           /*
            * XXX(hch): we really should not let host device detection
            * override an explicit protocol specification, but moving this
            * later breaks access to device names with colons in them.
            * Thanks to the brain-dead persistent naming schemes on udev-
            * based Linux systems those actually are quite common.
            */
           drv1 = find_hdev_driver(filename);
           if (drv1) {
               return drv1;
+          }
           if (!path_has_protocol(filename) || !allow_protocol_prefix) {
               return bdrv_find_format("file");
+          }
           p = strchr(filename, ':');
           assert(p != NULL);
           len = p - filename;
           if (len > sizeof(protocol) - 1)
               len = sizeof(protocol) - 1;
           memcpy(protocol, filename, len);
           protocol[len] = '\0';
           QLIST_FOREACH(drv1, &bdrv_drivers, list) {
               if (drv1->protocol_name &&
                   !strcmp(drv1->protocol_name, protocol)) {
                   return drv1;
+              }
+          }
           return NULL;
+      }
       static int find_image_format(BlockDriverState *bs, const char *filename,
                                    BlockDriver **pdrv, Error **errp)
+      {
           int score, score_max;
           BlockDriver *drv1, *drv;
           uint8_t buf[2048];
           int ret = 0;
           /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
           if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
               drv = bdrv_find_format("raw");
               if (!drv) {
                   error_setg(errp, "Could not find raw image format");
                   ret = -ENOENT;
+              }
               *pdrv = drv;
               return ret;
+          }
           ret = bdrv_pread(bs, 0, buf, sizeof(buf));
           if (ret < 0) {
               error_setg_errno(errp, -ret, "Could not read image for determining its "
                                "format");
               *pdrv = NULL;
               return ret;
+          }
           score_max = 0;
           drv = NULL;
           QLIST_FOREACH(drv1, &bdrv_drivers, list) {
               if (drv1->bdrv_probe) {
                   score = drv1->bdrv_probe(buf, ret, filename);
                   if (score > score_max) {
                       score_max = score;
                       drv = drv1;
+                  }
+              }
+          }
           if (!drv) {
               error_setg(errp, "Could not determine image format: No compatible "
                          "driver found");
               ret = -ENOENT;
+          }
           *pdrv = drv;
           return ret;
+      }
       /**
        * Set the current 'total_sectors' value
        */
       static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
+      {
           BlockDriver *drv = bs->drv;
           /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
           if (bs->sg)
               return 0;
           /* query actual device if possible, otherwise just trust the hint */
           if (drv->bdrv_getlength) {
               int64_t length = drv->bdrv_getlength(bs);
               if (length < 0) {
                   return length;
+              }
               hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
+          }
           bs->total_sectors = hint;
           return 0;
+      }
       /**
        * Set open flags for a given discard mode
+       *
        * Return 0 on success, -1 if the discard mode was invalid.
        */
       int bdrv_parse_discard_flags(const char *mode, int *flags)
+      {
           *flags &= ~BDRV_O_UNMAP;
           if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
               /* do nothing */
           } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
               *flags |= BDRV_O_UNMAP;
           } else {
               return -1;
+          }
           return 0;
+      }
       /**
        * Set open flags for a given cache mode
+       *
        * Return 0 on success, -1 if the cache mode was invalid.
        */
       int bdrv_parse_cache_flags(const char *mode, int *flags)
+      {
           *flags &= ~BDRV_O_CACHE_MASK;
           if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
               *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
           } else if (!strcmp(mode, "directsync")) {
               *flags |= BDRV_O_NOCACHE;
           } else if (!strcmp(mode, "writeback")) {
               *flags |= BDRV_O_CACHE_WB;
           } else if (!strcmp(mode, "unsafe")) {
               *flags |= BDRV_O_CACHE_WB;
               *flags |= BDRV_O_NO_FLUSH;
           } else if (!strcmp(mode, "writethrough")) {
               /* this is the default */
           } else {
               return -1;
+          }
           return 0;
+      }
       /**
        * The copy-on-read flag is actually a reference count so multiple users may
        * use the feature without worrying about clobbering its previous state.
        * Copy-on-read stays enabled until all users have called to disable it.
        */
       void bdrv_enable_copy_on_read(BlockDriverState *bs)
+      {
           bs->copy_on_read++;
+      }
       void bdrv_disable_copy_on_read(BlockDriverState *bs)
+      {
           assert(bs->copy_on_read > 0);
           bs->copy_on_read--;
+      }
       static int bdrv_open_flags(BlockDriverState *bs, int flags)
+      {
           int open_flags = flags | BDRV_O_CACHE_WB;
           /*
            * Clear flags that are internal to the block layer before opening the
            * image.
            */
           open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
           /*
            * Snapshots should be writable.
            */
           if (bs->is_temporary) {
               open_flags |= BDRV_O_RDWR;
+          }
           return open_flags;
+      }
       static int bdrv_assign_node_name(BlockDriverState *bs,
                                        const char *node_name,
                                        Error **errp)
+      {
           if (!node_name) {
               return 0;
+          }
           /* empty string node name is invalid */
           if (node_name[0] == '\0') {
               error_setg(errp, "Empty node name");
               return -EINVAL;
+          }
           /* takes care of avoiding duplicates node names */
           if (bdrv_find_node(node_name)) {
               error_setg(errp, "Duplicate node name");
               return -EINVAL;
+          }
           /* copy node name into the bs and insert it into the graph list */
           pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
           QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
           return 0;
+      }
       /*
        * Common part for opening disk images and files
+       *
        * Removes all processed options from *options.
        */
       static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
           QDict *options, int flags, BlockDriver *drv, Error **errp)
+      {
           int ret, open_flags;
           const char *filename;
           const char *node_name = NULL;
           Error *local_err = NULL;
           assert(drv != NULL);
           assert(bs->file == NULL);
           assert(options != NULL && bs->options != options);
           if (file != NULL) {
               filename = file->filename;
           } else {
               filename = qdict_get_try_str(options, "filename");
+          }
           trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);
           node_name = qdict_get_try_str(options, "node-name");
           ret = bdrv_assign_node_name(bs, node_name, errp);
           if (ret < 0) {
               return ret;
+          }
           qdict_del(options, "node-name");
           /* bdrv_open() with directly using a protocol as drv. This layer is already
            * opened, so assign it to bs (while file becomes a closed BlockDriverState)
            * and return immediately. */
           if (file != NULL && drv->bdrv_file_open) {
               bdrv_swap(file, bs);
               return 0;
+          }
           bs->open_flags = flags;
           bs->guest_block_size = 512;
           bs->request_alignment = 512;
           bs->zero_beyond_eof = true;
           open_flags = bdrv_open_flags(bs, flags);
           bs->read_only = !(open_flags & BDRV_O_RDWR);
           if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
               error_setg(errp,
                          !bs->read_only && bdrv_is_whitelisted(drv, true)
                               ? "Driver '%s' can only be used for read-only devices"
                               : "Driver '%s' is not whitelisted",
                          drv->format_name);
               return -ENOTSUP;
+          }
           assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
           if (flags & BDRV_O_COPY_ON_READ) {
               if (!bs->read_only) {
                   bdrv_enable_copy_on_read(bs);
               } else {
                   error_setg(errp, "Can't use copy-on-read on read-only device");
                   return -EINVAL;
+              }
+          }
           if (filename != NULL) {
               pstrcpy(bs->filename, sizeof(bs->filename), filename);
           } else {
               bs->filename[0] = '\0';
+          }
           bs->drv = drv;
           bs->opaque = g_malloc0(drv->instance_size);
           bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB);
           /* Open the image, either directly or using a protocol */
           if (drv->bdrv_file_open) {
               assert(file == NULL);
               assert(!drv->bdrv_needs_filename || filename != NULL);
               ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
           } else {
               if (file == NULL) {
                   error_setg(errp, "Can't use '%s' as a block driver for the "
                              "protocol level", drv->format_name);
                   ret = -EINVAL;
                   goto free_and_fail;
+              }
               bs->file = file;
               ret = drv->bdrv_open(bs, options, open_flags, &local_err);
+          }
           if (ret < 0) {
               if (error_is_set(&local_err)) {
                   error_propagate(errp, local_err);
               } else if (bs->filename[0]) {
                   error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
               } else {
                   error_setg_errno(errp, -ret, "Could not open image");
+              }
               goto free_and_fail;
+          }
           ret = refresh_total_sectors(bs, bs->total_sectors);
           if (ret < 0) {
               error_setg_errno(errp, -ret, "Could not refresh total sector count");
               goto free_and_fail;
+          }
           bdrv_refresh_limits(bs);
           assert(bdrv_opt_mem_align(bs) != 0);
           assert(bs->request_alignment != 0);
       #ifndef _WIN32
           if (bs->is_temporary) {
               assert(bs->filename[0] != '\0');
               unlink(bs->filename);
+          }
       #endif
           return 0;
       free_and_fail:
           bs->file = NULL;
           g_free(bs->opaque);
           bs->opaque = NULL;
           bs->drv = NULL;
           return ret;
+      }
       /*
        * Opens a file using a protocol (file, host_device, nbd, ...)
+       *
        * options is a QDict of options to pass to the block drivers, or NULL for an
        * empty set of options. The reference to the QDict belongs to the block layer
        * after the call (even on failure), so if the caller intends to reuse the
        * dictionary, it needs to use QINCREF() before calling bdrv_file_open.
        */
       int bdrv_file_open(BlockDriverState **pbs, const char *filename,
                          const char *reference, QDict *options, int flags,
                          Error **errp)
+      {
           BlockDriverState *bs = NULL;
           BlockDriver *drv;
           const char *drvname;
           bool allow_protocol_prefix = false;
           Error *local_err = NULL;
           int ret;
           /* NULL means an empty set of options */
           if (options == NULL) {
               options = qdict_new();
+          }
           if (reference) {
               if (filename || qdict_size(options)) {
                   error_setg(errp, "Cannot reference an existing block device with "
                              "additional options or a new filename");
                   return -EINVAL;
+              }
               QDECREF(options);
               bs = bdrv_find(reference);
               if (!bs) {
                   error_setg(errp, "Cannot find block device '%s'", reference);
                   return -ENODEV;
+              }
               bdrv_ref(bs);
               *pbs = bs;
               return 0;
+          }
           bs = bdrv_new("");
           bs->options = options;
           options = qdict_clone_shallow(options);
           /* Fetch the file name from the options QDict if necessary */
           if (!filename) {
               filename = qdict_get_try_str(options, "filename");
           } else if (filename && !qdict_haskey(options, "filename")) {
               qdict_put(options, "filename", qstring_from_str(filename));
               allow_protocol_prefix = true;
           } else {
               error_setg(errp, "Can't specify 'file' and 'filename' options at the "
                          "same time");
               ret = -EINVAL;
               goto fail;
+          }
           /* Find the right block driver */
           drvname = qdict_get_try_str(options, "driver");
           if (drvname) {
               drv = bdrv_find_format(drvname);
               if (!drv) {
                   error_setg(errp, "Unknown driver '%s'", drvname);
+              }
               qdict_del(options, "driver");
           } else if (filename) {
               drv = bdrv_find_protocol(filename, allow_protocol_prefix);
               if (!drv) {
                   error_setg(errp, "Unknown protocol");
+              }
           } else {
               error_setg(errp, "Must specify either driver or file");
               drv = NULL;
+          }
           if (!drv) {
               /* errp has been set already */
               ret = -ENOENT;
               goto fail;
+          }
           /* Parse the filename and open it */
           if (drv->bdrv_parse_filename && filename) {
               drv->bdrv_parse_filename(filename, options, &local_err);
               if (error_is_set(&local_err)) {
                   error_propagate(errp, local_err);
                   ret = -EINVAL;
                   goto fail;
+              }
               qdict_del(options, "filename");
           } else if (drv->bdrv_needs_filename && !filename) {
               error_setg(errp, "The '%s' block driver requires a file name",
                          drv->format_name);
               ret = -EINVAL;
               goto fail;
+          }
           if (!drv->bdrv_file_open) {
               ret = bdrv_open(bs, filename, options, flags, drv, &local_err);
               options = NULL;
           } else {
               ret = bdrv_open_common(bs, NULL, options, flags, drv, &local_err);
+          }
           if (ret < 0) {
               error_propagate(errp, local_err);
               goto fail;
+          }
           /* Check if any unknown options were used */
           if (options && (qdict_size(options) != 0)) {
               const QDictEntry *entry = qdict_first(options);
               error_setg(errp, "Block protocol '%s' doesn't support the option '%s'",
                          drv->format_name, entry->key);
               ret = -EINVAL;
               goto fail;
+          }
           QDECREF(options);
           bs->growable = 1;
           *pbs = bs;
           return 0;
       fail:
           QDECREF(options);
           if (!bs->drv) {
               QDECREF(bs->options);
+          }
           bdrv_unref(bs);
           return ret;
+      }
       /*
        * Opens the backing file for a BlockDriverState if not yet open
+       *
        * options is a QDict of options to pass to the block drivers, or NULL for an
        * empty set of options. The reference to the QDict is transferred to this
        * function (even on failure), so if the caller intends to reuse the dictionary,
        * it needs to use QINCREF() before calling bdrv_file_open.
        */
       int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp)
+      {
           char backing_filename[PATH_MAX];
           int back_flags, ret;
           BlockDriver *back_drv = NULL;
           Error *local_err = NULL;
           if (bs->backing_hd != NULL) {
               QDECREF(options);
               return 0;
+          }
           /* NULL means an empty set of options */
           if (options == NULL) {
               options = qdict_new();
+          }
           bs->open_flags &= ~BDRV_O_NO_BACKING;
           if (qdict_haskey(options, "file.filename")) {
               backing_filename[0] = '\0';
           } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
               QDECREF(options);
               return 0;
           } else {
               bdrv_get_full_backing_filename(bs, backing_filename,
                                              sizeof(backing_filename));
+          }
           bs->backing_hd = bdrv_new("");
           if (bs->backing_format[0] != '\0') {
               back_drv = bdrv_find_format(bs->backing_format);
+          }
           /* backing files always opened read-only */
           back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT |
                                           BDRV_O_COPY_ON_READ);
           ret = bdrv_open(bs->backing_hd,
                           *backing_filename ? backing_filename : NULL, options,
                           back_flags, back_drv, &local_err);
           if (ret < 0) {
               bdrv_unref(bs->backing_hd);
               bs->backing_hd = NULL;
               bs->open_flags |= BDRV_O_NO_BACKING;
               error_setg(errp, "Could not open backing file: %s",
                          error_get_pretty(local_err));
               error_free(local_err);
               return ret;
+          }
           if (bs->backing_hd->file) {
               pstrcpy(bs->backing_file, sizeof(bs->backing_file),
                       bs->backing_hd->file->filename);
+          }
           /* Recalculate the BlockLimits with the backing file */
           bdrv_refresh_limits(bs);
           return 0;
+      }
       /*
        * Opens a disk image whose options are given as BlockdevRef in another block
        * device's options.
+       *
        * If force_raw is true, bdrv_file_open() will be used, thereby preventing any
        * image format auto-detection. If it is false and a filename is given,
        * bdrv_open() will be used for auto-detection.
+       *
        * If allow_none is true, no image will be opened if filename is false and no
        * BlockdevRef is given. *pbs will remain unchanged and 0 will be returned.
+       *
        * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
        * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
        * itself, all options starting with "${bdref_key}." are considered part of the
        * BlockdevRef.
+       *
        * The BlockdevRef will be removed from the options QDict.
        */
       int bdrv_open_image(BlockDriverState **pbs, const char *filename,
                           QDict *options, const char *bdref_key, int flags,
                           bool force_raw, bool allow_none, Error **errp)
+      {
           QDict *image_options;
           int ret;
           char *bdref_key_dot;
           const char *reference;
           bdref_key_dot = g_strdup_printf("%s.", bdref_key);
           qdict_extract_subqdict(options, &image_options, bdref_key_dot);
           g_free(bdref_key_dot);
           reference = qdict_get_try_str(options, bdref_key);
           if (!filename && !reference && !qdict_size(image_options)) {
               if (allow_none) {
                   ret = 0;
               } else {
                   error_setg(errp, "A block device must be specified for \"%s\"",
                              bdref_key);
                   ret = -EINVAL;
+              }
               goto done;
+          }
           if (filename && !force_raw) {
               /* If a filename is given and the block driver should be detected
                  automatically (instead of using none), use bdrv_open() in order to do
                  that auto-detection. */
               BlockDriverState *bs;
               if (reference) {
                   error_setg(errp, "Cannot reference an existing block device while "
                              "giving a filename");
                   ret = -EINVAL;
                   goto done;
+              }
               bs = bdrv_new("");
               ret = bdrv_open(bs, filename, image_options, flags, NULL, errp);
               if (ret < 0) {
                   bdrv_unref(bs);
               } else {
                   *pbs = bs;
+              }
           } else {
               ret = bdrv_file_open(pbs, filename, reference, image_options, flags,
                                    errp);
+          }
       done:
           qdict_del(options, bdref_key);
           return ret;
+      }
       /*
        * Opens a disk image (raw, qcow2, vmdk, ...)
+       *
        * options is a QDict of options to pass to the block drivers, or NULL for an
        * empty set of options. The reference to the QDict belongs to the block layer
        * after the call (even on failure), so if the caller intends to reuse the
        * dictionary, it needs to use QINCREF() before calling bdrv_open.
        */
       int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
                     int flags, BlockDriver *drv, Error **errp)
+      {
           int ret;
           /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
           char tmp_filename[PATH_MAX + 1];
           BlockDriverState *file = NULL;
           const char *drvname;
           Error *local_err = NULL;
           /* NULL means an empty set of options */
           if (options == NULL) {
               options = qdict_new();
+          }
           bs->options = options;
           options = qdict_clone_shallow(options);
           /* For snapshot=on, create a temporary qcow2 overlay */
           if (flags & BDRV_O_SNAPSHOT) {
               BlockDriverState *bs1;
               int64_t total_size;
               BlockDriver *bdrv_qcow2;
               QEMUOptionParameter *create_options;
               QDict *snapshot_options;
               /* if snapshot, we create a temporary backing file and open it
                  instead of opening 'filename' directly */
               /* Get the required size from the image */
               bs1 = bdrv_new("");
               QINCREF(options);
               ret = bdrv_open(bs1, filename, options, BDRV_O_NO_BACKING,
                               drv, &local_err);
               if (ret < 0) {
                   bdrv_unref(bs1);
                   goto fail;
+              }
               total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK;
               bdrv_unref(bs1);
               /* Create the temporary image */
               ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename));
               if (ret < 0) {
                   error_setg_errno(errp, -ret, "Could not get temporary filename");
                   goto fail;
+              }
               bdrv_qcow2 = bdrv_find_format("qcow2");
               create_options = parse_option_parameters("", bdrv_qcow2->create_options,
                                                        NULL);
               set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size);
               ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err);
               free_option_parameters(create_options);
               if (ret < 0) {
                   error_setg_errno(errp, -ret, "Could not create temporary overlay "
                                    "'%s': %s", tmp_filename,
                                    error_get_pretty(local_err));
                   error_free(local_err);
                   local_err = NULL;
                   goto fail;
+              }
               /* Prepare a new options QDict for the temporary file, where user
                * options refer to the backing file */
               if (filename) {
                   qdict_put(options, "file.filename", qstring_from_str(filename));
+              }
               if (drv) {
                   qdict_put(options, "driver", qstring_from_str(drv->format_name));
+              }
               snapshot_options = qdict_new();
               qdict_put(snapshot_options, "backing", options);
               qdict_flatten(snapshot_options);
               bs->options = snapshot_options;
               options = qdict_clone_shallow(bs->options);
               filename = tmp_filename;
               drv = bdrv_qcow2;
               bs->is_temporary = 1;
+          }
           /* Open image file without format layer */
           if (flags & BDRV_O_RDWR) {
               flags |= BDRV_O_ALLOW_RDWR;
+          }
           ret = bdrv_open_image(&file, filename, options, "file",
                                 bdrv_open_flags(bs, flags | BDRV_O_UNMAP), true, true,
                                 &local_err);
           if (ret < 0) {
               goto fail;
+          }
           /* Find the right image format driver */
           drvname = qdict_get_try_str(options, "driver");
           if (drvname) {
               drv = bdrv_find_format(drvname);
               qdict_del(options, "driver");
               if (!drv) {
                   error_setg(errp, "Invalid driver: '%s'", drvname);
                   ret = -EINVAL;
                   goto unlink_and_fail;
+              }
+          }
           if (!drv) {
               if (file) {
                   ret = find_image_format(file, filename, &drv, &local_err);
               } else {
                   error_setg(errp, "Must specify either driver or file");
                   ret = -EINVAL;
                   goto unlink_and_fail;
+              }
+          }
           if (!drv) {
               goto unlink_and_fail;
+          }
           /* Open the image */
           ret = bdrv_open_common(bs, file, options, flags, drv, &local_err);
           if (ret < 0) {
               goto unlink_and_fail;
+          }
           if (file && (bs->file != file)) {
               bdrv_unref(file);
               file = NULL;
+          }
           /* If there is a backing file, use it */
           if ((flags & BDRV_O_NO_BACKING) == 0) {
               QDict *backing_options;
               qdict_extract_subqdict(options, &backing_options, "backing.");
               ret = bdrv_open_backing_file(bs, backing_options, &local_err);
               if (ret < 0) {
                   goto close_and_fail;
+              }
+          }
           /* Check if any unknown options were used */
           if (qdict_size(options) != 0) {
               const QDictEntry *entry = qdict_first(options);
               error_setg(errp, "Block format '%s' used by device '%s' doesn't "
                          "support the option '%s'", drv->format_name, bs->device_name,
                          entry->key);
               ret = -EINVAL;
               goto close_and_fail;
+          }
           QDECREF(options);
           if (!bdrv_key_required(bs)) {
               bdrv_dev_change_media_cb(bs, true);
+          }
           return 0;
       unlink_and_fail:
           if (file != NULL) {
               bdrv_unref(file);
+          }
           if (bs->is_temporary) {
               unlink(filename);
+          }
       fail:
           QDECREF(bs->options);
           QDECREF(options);
           bs->options = NULL;
           if (error_is_set(&local_err)) {
               error_propagate(errp, local_err);
+          }
           return ret;
       close_and_fail:
           bdrv_close(bs);
           QDECREF(options);
           if (error_is_set(&local_err)) {
               error_propagate(errp, local_err);
+          }
           return ret;
+      }
       typedef struct BlockReopenQueueEntry {
            bool prepared;
            BDRVReopenState state;
            QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
       } BlockReopenQueueEntry;
       /*
        * Adds a BlockDriverState to a simple queue for an atomic, transactional
        * reopen of multiple devices.
+       *
        * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
        * already performed, or alternatively may be NULL a new BlockReopenQueue will
        * be created and initialized. This newly created BlockReopenQueue should be
        * passed back in for subsequent calls that are intended to be of the same
        * atomic 'set'.
+       *
        * bs is the BlockDriverState to add to the reopen queue.
+       *
        * flags contains the open flags for the associated bs
+       *
        * returns a pointer to bs_queue, which is either the newly allocated
        * bs_queue, or the existing bs_queue being used.
+       *
        */
       BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                           BlockDriverState *bs, int flags)
+      {
           assert(bs != NULL);
           BlockReopenQueueEntry *bs_entry;
           if (bs_queue == NULL) {
               bs_queue = g_new0(BlockReopenQueue, 1);
               QSIMPLEQ_INIT(bs_queue);
+          }
           if (bs->file) {
               bdrv_reopen_queue(bs_queue, bs->file, flags);
+          }
           bs_entry = g_new0(BlockReopenQueueEntry, 1);
           QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
           bs_entry->state.bs = bs;
           bs_entry->state.flags = flags;
           return bs_queue;
+      }
       /*
        * Reopen multiple BlockDriverStates atomically & transactionally.
+       *
        * The queue passed in (bs_queue) must have been built up previous
        * via bdrv_reopen_queue().
+       *
        * Reopens all BDS specified in the queue, with the appropriate
        * flags.  All devices are prepared for reopen, and failure of any
        * device will cause all device changes to be abandonded, and intermediate
        * data cleaned up.
+       *
        * If all devices prepare successfully, then the changes are committed
        * to all devices.
+       *
        */
       int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
+      {
           int ret = -1;
           BlockReopenQueueEntry *bs_entry, *next;
           Error *local_err = NULL;
           assert(bs_queue != NULL);
           bdrv_drain_all();
           QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
               if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
                   error_propagate(errp, local_err);
                   goto cleanup;
+              }
               bs_entry->prepared = true;
+          }
           /* If we reach this point, we have success and just need to apply the
            * changes
            */
           QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
               bdrv_reopen_commit(&bs_entry->state);
+          }
           ret = 0;
       cleanup:
           QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
               if (ret && bs_entry->prepared) {
                   bdrv_reopen_abort(&bs_entry->state);
+              }
               g_free(bs_entry);
+          }
           g_free(bs_queue);
           return ret;
+      }
       /* Reopen a single BlockDriverState with the specified flags. */
       int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
+      {
           int ret = -1;
           Error *local_err = NULL;
           BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, bdrv_flags);
           ret = bdrv_reopen_multiple(queue, &local_err);
           if (local_err != NULL) {
               error_propagate(errp, local_err);
+          }
           return ret;
+      }
       /*
        * Prepares a BlockDriverState for reopen. All changes are staged in the
        * 'opaque' field of the BDRVReopenState, which is used and allocated by
        * the block driver layer .bdrv_reopen_prepare()
+       *
        * bs is the BlockDriverState to reopen
        * flags are the new open flags
        * queue is the reopen queue
+       *
        * Returns 0 on success, non-zero on error.  On error errp will be set
        * as well.
+       *
        * On failure, bdrv_reopen_abort() will be called to clean up any data.
        * It is the responsibility of the caller to then call the abort() or
        * commit() for any other BDS that have been left in a prepare() state
+       *
        */
       int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
                               Error **errp)
+      {
           int ret = -1;
           Error *local_err = NULL;
           BlockDriver *drv;
           assert(reopen_state != NULL);
           assert(reopen_state->bs->drv != NULL);
           drv = reopen_state->bs->drv;
           /* if we are to stay read-only, do not allow permission change
            * to r/w */
           if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
               reopen_state->flags & BDRV_O_RDWR) {
               error_set(errp, QERR_DEVICE_IS_READ_ONLY,
                         reopen_state->bs->device_name);
               goto error;
+          }
           ret = bdrv_flush(reopen_state->bs);
           if (ret) {
               error_set(errp, ERROR_CLASS_GENERIC_ERROR, "Error (%s) flushing drive",
                         strerror(-ret));
               goto error;
+          }
           if (drv->bdrv_reopen_prepare) {
               ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
               if (ret) {
                   if (local_err != NULL) {
                       error_propagate(errp, local_err);
                   } else {
                       error_setg(errp, "failed while preparing to reopen image '%s'",
                                  reopen_state->bs->filename);
+                  }
                   goto error;
+              }
           } else {
               /* It is currently mandatory to have a bdrv_reopen_prepare()
                * handler for each supported drv. */
               error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
                         drv->format_name, reopen_state->bs->device_name,
                        "reopening of file");
               ret = -1;
               goto error;
+          }
           ret = 0;
       error:
           return ret;
+      }
       /*
        * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
        * makes them final by swapping the staging BlockDriverState contents into
        * the active BlockDriverState contents.
        */
       void bdrv_reopen_commit(BDRVReopenState *reopen_state)
+      {
           BlockDriver *drv;
           assert(reopen_state != NULL);
           drv = reopen_state->bs->drv;
           assert(drv != NULL);
           /* If there are any driver level actions to take */
           if (drv->bdrv_reopen_commit) {
               drv->bdrv_reopen_commit(reopen_state);
+          }
           /* set BDS specific flags now */
           reopen_state->bs->open_flags         = reopen_state->flags;
           reopen_state->bs->enable_write_cache = !!(reopen_state->flags &
                                                     BDRV_O_CACHE_WB);
           reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
           bdrv_refresh_limits(reopen_state->bs);
+      }
       /*
        * Abort the reopen, and delete and free the staged changes in
        * reopen_state
        */
       void bdrv_reopen_abort(BDRVReopenState *reopen_state)
+      {
           BlockDriver *drv;
           assert(reopen_state != NULL);
           drv = reopen_state->bs->drv;
           assert(drv != NULL);
           if (drv->bdrv_reopen_abort) {
               drv->bdrv_reopen_abort(reopen_state);
+          }
+      }
       void bdrv_close(BlockDriverState *bs)
+      {
           if (bs->job) {
               block_job_cancel_sync(bs->job);
+          }
           bdrv_drain_all(); /* complete I/O */
           bdrv_flush(bs);
           bdrv_drain_all(); /* in case flush left pending I/O */
           notifier_list_notify(&bs->close_notifiers, bs);
           if (bs->drv) {
               if (bs->backing_hd) {
                   bdrv_unref(bs->backing_hd);
                   bs->backing_hd = NULL;
+              }
               bs->drv->bdrv_close(bs);
               g_free(bs->opaque);
       #ifdef _WIN32
               if (bs->is_temporary) {
                   unlink(bs->filename);
+              }
       #endif
               bs->opaque = NULL;
               bs->drv = NULL;
               bs->copy_on_read = 0;
               bs->backing_file[0] = '\0';
               bs->backing_format[0] = '\0';
               bs->total_sectors = 0;
               bs->encrypted = 0;
               bs->valid_key = 0;
               bs->sg = 0;
               bs->growable = 0;
               bs->zero_beyond_eof = false;
               QDECREF(bs->options);
               bs->options = NULL;
               if (bs->file != NULL) {
                   bdrv_unref(bs->file);
                   bs->file = NULL;
+              }
+          }
           bdrv_dev_change_media_cb(bs, false);
           /*throttling disk I/O limits*/
           if (bs->io_limits_enabled) {
               bdrv_io_limits_disable(bs);
+          }
+      }
       void bdrv_close_all(void)
+      {
           BlockDriverState *bs;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               bdrv_close(bs);
+          }
+      }
       /* Check if any requests are in-flight (including throttled requests) */
       static bool bdrv_requests_pending(BlockDriverState *bs)
+      {
           if (!QLIST_EMPTY(&bs->tracked_requests)) {
               return true;
+          }
           if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) {
               return true;
+          }
           if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) {
               return true;
+          }
           if (bs->file && bdrv_requests_pending(bs->file)) {
               return true;
+          }
           if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) {
               return true;
+          }
           return false;
+      }
       static bool bdrv_requests_pending_all(void)
+      {
           BlockDriverState *bs;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               if (bdrv_requests_pending(bs)) {
                   return true;
+              }
+          }
           return false;
+      }
       /*
        * Wait for pending requests to complete across all BlockDriverStates
+       *
        * This function does not flush data to disk, use bdrv_flush_all() for that
        * after calling this function.
+       *
        * Note that completion of an asynchronous I/O operation can trigger any
        * number of other I/O operations on other devices---for example a coroutine
        * can be arbitrarily complex and a constant flow of I/O can come until the
        * coroutine is complete.  Because of this, it is not possible to have a
        * function to drain a single device's I/O queue.
        */
       void bdrv_drain_all(void)
+      {
           /* Always run first iteration so any pending completion BHs run */
           bool busy = true;
           BlockDriverState *bs;
           while (busy) {
               QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
                   bdrv_start_throttled_reqs(bs);
+              }
               busy = bdrv_requests_pending_all();
               busy |= aio_poll(qemu_get_aio_context(), busy);
+          }
+      }
       /* make a BlockDriverState anonymous by removing from bdrv_state and
        * graph_bdrv_state list.
          Also, NULL terminate the device_name to prevent double remove */
       void bdrv_make_anon(BlockDriverState *bs)
+      {
           if (bs->device_name[0] != '\0') {
               QTAILQ_REMOVE(&bdrv_states, bs, device_list);
+          }
           bs->device_name[0] = '\0';
           if (bs->node_name[0] != '\0') {
               QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
+          }
           bs->node_name[0] = '\0';
+      }
       static void bdrv_rebind(BlockDriverState *bs)
+      {
           if (bs->drv && bs->drv->bdrv_rebind) {
               bs->drv->bdrv_rebind(bs);
+          }
+      }
       static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
                                            BlockDriverState *bs_src)
+      {
           /* move some fields that need to stay attached to the device */
           bs_dest->open_flags         = bs_src->open_flags;
           /* dev info */
           bs_dest->dev_ops            = bs_src->dev_ops;
           bs_dest->dev_opaque         = bs_src->dev_opaque;
           bs_dest->dev                = bs_src->dev;
           bs_dest->guest_block_size   = bs_src->guest_block_size;
           bs_dest->copy_on_read       = bs_src->copy_on_read;
           bs_dest->enable_write_cache = bs_src->enable_write_cache;
           /* i/o throttled req */
           memcpy(&bs_dest->throttle_state,
                  &bs_src->throttle_state,
                  sizeof(ThrottleState));
           bs_dest->throttled_reqs[0]  = bs_src->throttled_reqs[0];
           bs_dest->throttled_reqs[1]  = bs_src->throttled_reqs[1];
           bs_dest->io_limits_enabled  = bs_src->io_limits_enabled;
           /* r/w error */
           bs_dest->on_read_error      = bs_src->on_read_error;
           bs_dest->on_write_error     = bs_src->on_write_error;
           /* i/o status */
           bs_dest->iostatus_enabled   = bs_src->iostatus_enabled;
           bs_dest->iostatus           = bs_src->iostatus;
           /* dirty bitmap */
           bs_dest->dirty_bitmaps      = bs_src->dirty_bitmaps;
           /* reference count */
           bs_dest->refcnt             = bs_src->refcnt;
           /* job */
           bs_dest->in_use             = bs_src->in_use;
           bs_dest->job                = bs_src->job;
           /* keep the same entry in bdrv_states */
           pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name),
                   bs_src->device_name);
           bs_dest->device_list = bs_src->device_list;
           /* keep the same entry in graph_bdrv_states
            * We do want to swap name but don't want to swap linked list entries
            */
           bs_dest->node_list   = bs_src->node_list;
+      }
       /*
        * Swap bs contents for two image chains while they are live,
        * while keeping required fields on the BlockDriverState that is
        * actually attached to a device.
+       *
        * This will modify the BlockDriverState fields, and swap contents
        * between bs_new and bs_old. Both bs_new and bs_old are modified.
+       *
        * bs_new is required to be anonymous.
+       *
        * This function does not create any image files.
        */
       void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old)
+      {
           BlockDriverState tmp;
           /* bs_new must be anonymous and shouldn't have anything fancy enabled */
           assert(bs_new->device_name[0] == '\0');
           assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
           assert(bs_new->job == NULL);
           assert(bs_new->dev == NULL);
           assert(bs_new->in_use == 0);
           assert(bs_new->io_limits_enabled == false);
           assert(!throttle_have_timer(&bs_new->throttle_state));
           tmp = *bs_new;
           *bs_new = *bs_old;
           *bs_old = tmp;
           /* there are some fields that should not be swapped, move them back */
           bdrv_move_feature_fields(&tmp, bs_old);
           bdrv_move_feature_fields(bs_old, bs_new);
           bdrv_move_feature_fields(bs_new, &tmp);
           /* bs_new shouldn't be in bdrv_states even after the swap!  */
           assert(bs_new->device_name[0] == '\0');
           /* Check a few fields that should remain attached to the device */
           assert(bs_new->dev == NULL);
           assert(bs_new->job == NULL);
           assert(bs_new->in_use == 0);
           assert(bs_new->io_limits_enabled == false);
           assert(!throttle_have_timer(&bs_new->throttle_state));
           bdrv_rebind(bs_new);
           bdrv_rebind(bs_old);
+      }
       /*
        * Add new bs contents at the top of an image chain while the chain is
        * live, while keeping required fields on the top layer.
+       *
        * This will modify the BlockDriverState fields, and swap contents
        * between bs_new and bs_top. Both bs_new and bs_top are modified.
+       *
        * bs_new is required to be anonymous.
+       *
        * This function does not create any image files.
        */
       void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
+      {
           bdrv_swap(bs_new, bs_top);
           /* The contents of 'tmp' will become bs_top, as we are
            * swapping bs_new and bs_top contents. */
           bs_top->backing_hd = bs_new;
           bs_top->open_flags &= ~BDRV_O_NO_BACKING;
           pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file),
                   bs_new->filename);
           pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format),
                   bs_new->drv ? bs_new->drv->format_name : "");
+      }
       static void bdrv_delete(BlockDriverState *bs)
+      {
           assert(!bs->dev);
           assert(!bs->job);
           assert(!bs->in_use);
           assert(!bs->refcnt);
           assert(QLIST_EMPTY(&bs->dirty_bitmaps));
           bdrv_close(bs);
           /* remove from list, if necessary */
           bdrv_make_anon(bs);
           g_free(bs);
+      }
       int bdrv_attach_dev(BlockDriverState *bs, void *dev)
       /* TODO change to DeviceState *dev when all users are qdevified */
+      {
           if (bs->dev) {
               return -EBUSY;
+          }
           bs->dev = dev;
           bdrv_iostatus_reset(bs);
           return 0;
+      }
       /* TODO qdevified devices don't use this, remove when devices are qdevified */
       void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev)
+      {
           if (bdrv_attach_dev(bs, dev) < 0) {
               abort();
+          }
+      }
       void bdrv_detach_dev(BlockDriverState *bs, void *dev)
       /* TODO change to DeviceState *dev when all users are qdevified */
+      {
           assert(bs->dev == dev);
           bs->dev = NULL;
           bs->dev_ops = NULL;
           bs->dev_opaque = NULL;
           bs->guest_block_size = 512;
+      }
       /* TODO change to return DeviceState * when all users are qdevified */
       void *bdrv_get_attached_dev(BlockDriverState *bs)
+      {
           return bs->dev;
+      }
       void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
                             void *opaque)
+      {
           bs->dev_ops = ops;
           bs->dev_opaque = opaque;
+      }
       void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
                                      enum MonitorEvent ev,
                                      BlockErrorAction action, bool is_read)
+      {
           QObject *data;
           const char *action_str;
           switch (action) {
           case BDRV_ACTION_REPORT:
               action_str = "report";
               break;
           case BDRV_ACTION_IGNORE:
               action_str = "ignore";
               break;
           case BDRV_ACTION_STOP:
               action_str = "stop";
               break;
           default:
               abort();
+          }
           data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }",
                                     bdrv->device_name,
                                     action_str,
                                     is_read ? "read" : "write");
           monitor_protocol_event(ev, data);
           qobject_decref(data);
+      }
       static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected)
+      {
           QObject *data;
           data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }",
                                     bdrv_get_device_name(bs), ejected);
           monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data);
           qobject_decref(data);
+      }
       static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load)
+      {
           if (bs->dev_ops && bs->dev_ops->change_media_cb) {
               bool tray_was_closed = !bdrv_dev_is_tray_open(bs);
               bs->dev_ops->change_media_cb(bs->dev_opaque, load);
               if (tray_was_closed) {
                   /* tray open */
                   bdrv_emit_qmp_eject_event(bs, true);
+              }
               if (load) {
                   /* tray close */
                   bdrv_emit_qmp_eject_event(bs, false);
+              }
+          }
+      }
       bool bdrv_dev_has_removable_media(BlockDriverState *bs)
+      {
           return !bs->dev || (bs->dev_ops && bs->dev_ops->change_media_cb);
+      }
       void bdrv_dev_eject_request(BlockDriverState *bs, bool force)
+      {
           if (bs->dev_ops && bs->dev_ops->eject_request_cb) {
               bs->dev_ops->eject_request_cb(bs->dev_opaque, force);
+          }
+      }
       bool bdrv_dev_is_tray_open(BlockDriverState *bs)
+      {
           if (bs->dev_ops && bs->dev_ops->is_tray_open) {
               return bs->dev_ops->is_tray_open(bs->dev_opaque);
+          }
           return false;
+      }
       static void bdrv_dev_resize_cb(BlockDriverState *bs)
+      {
           if (bs->dev_ops && bs->dev_ops->resize_cb) {
               bs->dev_ops->resize_cb(bs->dev_opaque);
+          }
+      }
       bool bdrv_dev_is_medium_locked(BlockDriverState *bs)
+      {
           if (bs->dev_ops && bs->dev_ops->is_medium_locked) {
               return bs->dev_ops->is_medium_locked(bs->dev_opaque);
+          }
           return false;
+      }
       /*
        * Run consistency checks on an image
+       *
        * Returns 0 if the check could be completed (it doesn't mean that the image is
        * free of errors) or -errno when an internal error occurred. The results of the
        * check are stored in res.
        */
       int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
+      {
           if (bs->drv->bdrv_check == NULL) {
               return -ENOTSUP;
+          }
           memset(res, 0, sizeof(*res));
           return bs->drv->bdrv_check(bs, res, fix);
+      }
       #define COMMIT_BUF_SECTORS 2048
       /* commit COW file into the raw image */
       int bdrv_commit(BlockDriverState *bs)
+      {
           BlockDriver *drv = bs->drv;
           int64_t sector, total_sectors, length, backing_length;
           int n, ro, open_flags;
           int ret = 0;
           uint8_t *buf = NULL;
           char filename[PATH_MAX];
           if (!drv)
               return -ENOMEDIUM;
           if (!bs->backing_hd) {
               return -ENOTSUP;
+          }
           if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) {
               return -EBUSY;
+          }
           ro = bs->backing_hd->read_only;
           /* Use pstrcpy (not strncpy): filename must be NUL-terminated. */
           pstrcpy(filename, sizeof(filename), bs->backing_hd->filename);
           open_flags =  bs->backing_hd->open_flags;
           if (ro) {
               if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) {
                   return -EACCES;
+              }
+          }
           length = bdrv_getlength(bs);
           if (length < 0) {
               ret = length;
               goto ro_cleanup;
+          }
           backing_length = bdrv_getlength(bs->backing_hd);
           if (backing_length < 0) {
               ret = backing_length;
               goto ro_cleanup;
+          }
           /* If our top snapshot is larger than the backing file image,
            * grow the backing file image if possible.  If not possible,
            * we must return an error */
           if (length > backing_length) {
               ret = bdrv_truncate(bs->backing_hd, length);
               if (ret < 0) {
                   goto ro_cleanup;
+              }
+          }
           total_sectors = length >> BDRV_SECTOR_BITS;
           buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
           for (sector = 0; sector < total_sectors; sector += n) {
               ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n);
               if (ret < 0) {
                   goto ro_cleanup;
+              }
               if (ret) {
                   ret = bdrv_read(bs, sector, buf, n);
                   if (ret < 0) {
                       goto ro_cleanup;
+                  }
                   ret = bdrv_write(bs->backing_hd, sector, buf, n);
                   if (ret < 0) {
                       goto ro_cleanup;
+                  }
+              }
+          }
           if (drv->bdrv_make_empty) {
               ret = drv->bdrv_make_empty(bs);
               if (ret < 0) {
                   goto ro_cleanup;
+              }
               bdrv_flush(bs);
+          }
           /*
            * Make sure all data we wrote to the backing device is actually
            * stable on disk.
            */
           if (bs->backing_hd) {
               bdrv_flush(bs->backing_hd);
+          }
           ret = 0;
       ro_cleanup:
           g_free(buf);
           if (ro) {
               /* ignoring error return here */
               bdrv_reopen(bs->backing_hd, open_flags & ~BDRV_O_RDWR, NULL);
+          }
           return ret;
+      }
       int bdrv_commit_all(void)
+      {
           BlockDriverState *bs;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               if (bs->drv && bs->backing_hd) {
                   int ret = bdrv_commit(bs);
                   if (ret < 0) {
                       return ret;
+                  }
+              }
+          }
           return 0;
+      }
       /**
        * Remove an active request from the tracked requests list
+       *
        * This function should be called when a tracked request is completing.
        */
       static void tracked_request_end(BdrvTrackedRequest *req)
+      {
           if (req->serialising) {
               req->bs->serialising_in_flight--;
+          }
           QLIST_REMOVE(req, list);
           qemu_co_queue_restart_all(&req->wait_queue);
+      }
       /**
        * Add an active request to the tracked requests list
        */
       static void tracked_request_begin(BdrvTrackedRequest *req,
                                         BlockDriverState *bs,
                                         int64_t offset,
                                         unsigned int bytes, bool is_write)
+      {
           *req = (BdrvTrackedRequest){
               .bs = bs,
               .offset         = offset,
               .bytes          = bytes,
               .is_write       = is_write,
               .co             = qemu_coroutine_self(),
               .serialising    = false,
               .overlap_offset = offset,
               .overlap_bytes  = bytes,
           };
           qemu_co_queue_init(&req->wait_queue);
           QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
+      }
       static void mark_request_serialising(BdrvTrackedRequest *req, size_t align)
+      {
           int64_t overlap_offset = req->offset & ~(align - 1);
           int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
                             - overlap_offset;
           if (!req->serialising) {
               req->bs->serialising_in_flight++;
               req->serialising = true;
+          }
           req->overlap_offset = MIN(req->overlap_offset, overlap_offset);
           req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes);
+      }
       /**
        * Round a region to cluster boundaries
        */
       void bdrv_round_to_clusters(BlockDriverState *bs,
                                   int64_t sector_num, int nb_sectors,
                                   int64_t *cluster_sector_num,
                                   int *cluster_nb_sectors)
+      {
           BlockDriverInfo bdi;
           if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
               *cluster_sector_num = sector_num;
               *cluster_nb_sectors = nb_sectors;
           } else {
               int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE;
               *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c);
               *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num +
                                                   nb_sectors, c);
+          }
+      }
       static int bdrv_get_cluster_size(BlockDriverState *bs)
+      {
           BlockDriverInfo bdi;
           int ret;
           ret = bdrv_get_info(bs, &bdi);
           if (ret < 0 || bdi.cluster_size == 0) {
               return bs->request_alignment;
           } else {
               return bdi.cluster_size;
+          }
+      }
       static bool tracked_request_overlaps(BdrvTrackedRequest *req,
                                            int64_t offset, unsigned int bytes)
+      {
           /*        aaaa   bbbb */
           if (offset >= req->overlap_offset + req->overlap_bytes) {
               return false;
+          }
           /* bbbb   aaaa        */
           if (req->overlap_offset >= offset + bytes) {
               return false;
+          }
           return true;
+      }
       static void coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
+      {
           BlockDriverState *bs = self->bs;
           BdrvTrackedRequest *req;
           bool retry;
           if (!bs->serialising_in_flight) {
               return;
+          }
           do {
               retry = false;
               QLIST_FOREACH(req, &bs->tracked_requests, list) {
                   if (req == self || (!req->serialising && !self->serialising)) {
                       continue;
+                  }
                   if (tracked_request_overlaps(req, self->overlap_offset,
                                                self->overlap_bytes))
+                  {
                       /* Hitting this means there was a reentrant request, for
                        * example, a block driver issuing nested requests.  This must
                        * never happen since it means deadlock.
                        */
                       assert(qemu_coroutine_self() != req->co);
                       qemu_co_queue_wait(&req->wait_queue);
                       retry = true;
                       break;
+                  }
+              }
           } while (retry);
+      }
       /*
        * Return values:
        * 0        - success
        * -EINVAL  - backing format specified, but no file
        * -ENOSPC  - can't update the backing file because no space is left in the
        *            image file header
        * -ENOTSUP - format driver doesn't support changing the backing file
        */
       int bdrv_change_backing_file(BlockDriverState *bs,
           const char *backing_file, const char *backing_fmt)
+      {
           BlockDriver *drv = bs->drv;
           int ret;
           /* Backing file format doesn't make sense without a backing file */
           if (backing_fmt && !backing_file) {
               return -EINVAL;
+          }
           if (drv->bdrv_change_backing_file != NULL) {
               ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
           } else {
               ret = -ENOTSUP;
+          }
           if (ret == 0) {
               pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
               pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
+          }
           return ret;
+      }
       /*
        * Finds the image layer in the chain that has 'bs' as its backing file.
+       *
        * active is the current topmost image.
+       *
        * Returns NULL if bs is not found in active's image chain,
        * or if active == bs.
        */
       BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
                                           BlockDriverState *bs)
+      {
           BlockDriverState *overlay = NULL;
           BlockDriverState *intermediate;
           assert(active != NULL);
           assert(bs != NULL);
           /* if bs is the same as active, then by definition it has no overlay
            */
           if (active == bs) {
               return NULL;
+          }
           intermediate = active;
           while (intermediate->backing_hd) {
               if (intermediate->backing_hd == bs) {
                   overlay = intermediate;
                   break;
+              }
               intermediate = intermediate->backing_hd;
+          }
           return overlay;
+      }
       typedef struct BlkIntermediateStates {
           BlockDriverState *bs;
           QSIMPLEQ_ENTRY(BlkIntermediateStates) entry;
       } BlkIntermediateStates;
       /*
        * Drops images above 'base' up to and including 'top', and sets the image
        * above 'top' to have base as its backing file.
+       *
        * Requires that the overlay to 'top' is opened r/w, so that the backing file
        * information in 'bs' can be properly updated.
+       *
        * E.g., this will convert the following chain:
        * bottom <- base <- intermediate <- top <- active
+       *
        * to
+       *
        * bottom <- base <- active
+       *
        * It is allowed for bottom==base, in which case it converts:
+       *
        * base <- intermediate <- top <- active
+       *
        * to
+       *
        * base <- active
+       *
        * Error conditions:
        *  if active == top, that is considered an error
+       *
        */
       int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
                                  BlockDriverState *base)
+      {
           BlockDriverState *intermediate;
           BlockDriverState *base_bs = NULL;
           BlockDriverState *new_top_bs = NULL;
           BlkIntermediateStates *intermediate_state, *next;
           int ret = -EIO;
           QSIMPLEQ_HEAD(states_to_delete, BlkIntermediateStates) states_to_delete;
           QSIMPLEQ_INIT(&states_to_delete);
           if (!top->drv || !base->drv) {
               goto exit;
+          }
           new_top_bs = bdrv_find_overlay(active, top);
           if (new_top_bs == NULL) {
               /* we could not find the image above 'top', this is an error */
               goto exit;
+          }
           /* special case of new_top_bs->backing_hd already pointing to base - nothing
            * to do, no intermediate images */
           if (new_top_bs->backing_hd == base) {
               ret = 0;
               goto exit;
+          }
           intermediate = top;
           /* now we will go down through the list, and add each BDS we find
            * into our deletion queue, until we hit the 'base'
            */
           while (intermediate) {
               intermediate_state = g_malloc0(sizeof(BlkIntermediateStates));
               intermediate_state->bs = intermediate;
               QSIMPLEQ_INSERT_TAIL(&states_to_delete, intermediate_state, entry);
               if (intermediate->backing_hd == base) {
                   base_bs = intermediate->backing_hd;
                   break;
+              }
               intermediate = intermediate->backing_hd;
+          }
           if (base_bs == NULL) {
               /* something went wrong, we did not end at the base. safely
                * unravel everything, and exit with error */
               goto exit;
+          }
           /* success - we can delete the intermediate states, and link top->base */
           ret = bdrv_change_backing_file(new_top_bs, base_bs->filename,
                                          base_bs->drv ? base_bs->drv->format_name : "");
           if (ret) {
               goto exit;
+          }
           new_top_bs->backing_hd = base_bs;
           bdrv_refresh_limits(new_top_bs);
           QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) {
               /* so that bdrv_close() does not recursively close the chain */
               intermediate_state->bs->backing_hd = NULL;
               bdrv_unref(intermediate_state->bs);
+          }
           ret = 0;
       exit:
           QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) {
               g_free(intermediate_state);
+          }
           return ret;
+      }
       static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
                                          size_t size)
+      {
           int64_t len;
           if (!bdrv_is_inserted(bs))
               return -ENOMEDIUM;
           if (bs->growable)
               return 0;
           len = bdrv_getlength(bs);
           if (offset < 0)
               return -EIO;
           if ((offset > len) || (len - offset < size))
               return -EIO;
           return 0;
+      }
       static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
                                     int nb_sectors)
+      {
           return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE,
                                          nb_sectors * BDRV_SECTOR_SIZE);
+      }
       typedef struct RwCo {
           BlockDriverState *bs;
           int64_t sector_num;
           int nb_sectors;
           QEMUIOVector *qiov;
           bool is_write;
           int ret;
           BdrvRequestFlags flags;
       } RwCo;
       static void coroutine_fn bdrv_rw_co_entry(void *opaque)
+      {
           RwCo *rwco = opaque;
           if (!rwco->is_write) {
               rwco->ret = bdrv_co_do_readv(rwco->bs, rwco->sector_num,
                                            rwco->nb_sectors, rwco->qiov,
                                            rwco->flags);
           } else {
               rwco->ret = bdrv_co_do_writev(rwco->bs, rwco->sector_num,
                                             rwco->nb_sectors, rwco->qiov,
                                             rwco->flags);
+          }
+      }
       /*
        * Process a vectored synchronous request using coroutines
        */
       static int bdrv_rwv_co(BlockDriverState *bs, int64_t sector_num,
                              QEMUIOVector *qiov, bool is_write,
                              BdrvRequestFlags flags)
+      {
           Coroutine *co;
           RwCo rwco = {
               .bs = bs,
               .sector_num = sector_num,
               .nb_sectors = qiov->size >> BDRV_SECTOR_BITS,
               .qiov = qiov,
               .is_write = is_write,
               .ret = NOT_DONE,
               .flags = flags,
           };
           assert((qiov->size & (BDRV_SECTOR_SIZE - 1)) == 0);
           /**
            * In sync call context, when the vcpu is blocked, this throttling timer
            * will not fire; so the I/O throttling function has to be disabled here
            * if it has been enabled.
            */
           if (bs->io_limits_enabled) {
               fprintf(stderr, "Disabling I/O throttling on '%s' due "
                               "to synchronous I/O.\n", bdrv_get_device_name(bs));
               bdrv_io_limits_disable(bs);
+          }
           if (qemu_in_coroutine()) {
               /* Fast-path if already in coroutine context */
               bdrv_rw_co_entry(&rwco);
           } else {
               co = qemu_coroutine_create(bdrv_rw_co_entry);
               qemu_coroutine_enter(co, &rwco);
               while (rwco.ret == NOT_DONE) {
                   qemu_aio_wait();
+              }
+          }
           return rwco.ret;
+      }
       /*
        * Process a synchronous request using coroutines
        */
       static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
                             int nb_sectors, bool is_write, BdrvRequestFlags flags)
+      {
           QEMUIOVector qiov;
           struct iovec iov = {
               .iov_base = (void *)buf,
               .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
           };
           qemu_iovec_init_external(&qiov, &iov, 1);
           return bdrv_rwv_co(bs, sector_num, &qiov, is_write, flags);
+      }
       /* return < 0 if error. See bdrv_write() for the return codes */
       int bdrv_read(BlockDriverState *bs, int64_t sector_num,
                     uint8_t *buf, int nb_sectors)
+      {
           return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0);
+      }
       /* Just like bdrv_read(), but with I/O throttling temporarily disabled */
       int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num,
                                 uint8_t *buf, int nb_sectors)
+      {
           bool enabled;
           int ret;
           enabled = bs->io_limits_enabled;
           bs->io_limits_enabled = false;
           ret = bdrv_read(bs, sector_num, buf, nb_sectors);
           bs->io_limits_enabled = enabled;
           return ret;
+      }
       /* Return < 0 if error. Important errors are:
         -EIO         generic I/O error (may happen for all errors)
         -ENOMEDIUM   No media inserted.
         -EINVAL      Invalid sector number or nb_sectors
         -EACCES      Trying to write a read-only device
       */
       int bdrv_write(BlockDriverState *bs, int64_t sector_num,
                      const uint8_t *buf, int nb_sectors)
+      {
           return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0);
+      }
       int bdrv_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov)
+      {
           return bdrv_rwv_co(bs, sector_num, qiov, true, 0);
+      }
       int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num,
                             int nb_sectors, BdrvRequestFlags flags)
+      {
           return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true,
                             BDRV_REQ_ZERO_WRITE | flags);
+      }
       /*
        * Completely zero out a block device with the help of bdrv_write_zeroes.
        * The operation is sped up by checking the block status and only writing
        * zeroes to the device if they currently do not return zeroes. Optional
        * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP).
+       *
        * Returns < 0 on error, 0 on success. For error codes see bdrv_write().
        */
       int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
+      {
           int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE;
           int64_t ret, nb_sectors, sector_num = 0;
           int n;
           for (;;) {
               nb_sectors = target_size - sector_num;
               if (nb_sectors <= 0) {
                   return 0;
+              }
               if (nb_sectors > INT_MAX) {
                   nb_sectors = INT_MAX;
+              }
               ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
               if (ret < 0) {
                   error_report("error getting block status at sector %" PRId64 ": %s",
                                sector_num, strerror(-ret));
                   return ret;
+              }
               if (ret & BDRV_BLOCK_ZERO) {
                   sector_num += n;
                   continue;
+              }
               ret = bdrv_write_zeroes(bs, sector_num, n, flags);
               if (ret < 0) {
                   error_report("error writing zeroes at sector %" PRId64 ": %s",
                                sector_num, strerror(-ret));
                   return ret;
+              }
               sector_num += n;
+          }
+      }
       int bdrv_pread(BlockDriverState *bs, int64_t offset,
                      void *buf, int count1)
+      {
           uint8_t tmp_buf[BDRV_SECTOR_SIZE];
           int len, nb_sectors, count;
           int64_t sector_num;
           int ret;
           count = count1;
           /* first read to align to sector start */
           len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1);
           if (len > count)
               len = count;
           sector_num = offset >> BDRV_SECTOR_BITS;
           if (len > 0) {
               if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
                   return ret;
               memcpy(buf, tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)), len);
               count -= len;
               if (count == 0)
                   return count1;
               sector_num++;
               buf += len;
+          }
           /* read the sectors "in place" */
           nb_sectors = count >> BDRV_SECTOR_BITS;
           if (nb_sectors > 0) {
               if ((ret = bdrv_read(bs, sector_num, buf, nb_sectors)) < 0)
                   return ret;
               sector_num += nb_sectors;
               len = nb_sectors << BDRV_SECTOR_BITS;
               buf += len;
               count -= len;
+          }
           /* add data from the last sector */
           if (count > 0) {
               if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
                   return ret;
               memcpy(buf, tmp_buf, count);
+          }
           return count1;
+      }
       int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov)
+      {
           uint8_t tmp_buf[BDRV_SECTOR_SIZE];
           int len, nb_sectors, count;
           int64_t sector_num;
           int ret;
           count = qiov->size;
           /* first write to align to sector start */
           len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1);
           if (len > count)
               len = count;
           sector_num = offset >> BDRV_SECTOR_BITS;
           if (len > 0) {
               if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
                   return ret;
               qemu_iovec_to_buf(qiov, 0, tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)),
                                 len);
               if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0)
                   return ret;
               count -= len;
               if (count == 0)
                   return qiov->size;
               sector_num++;
+          }
           /* write the sectors "in place" */
           nb_sectors = count >> BDRV_SECTOR_BITS;
           if (nb_sectors > 0) {
               QEMUIOVector qiov_inplace;
               qemu_iovec_init(&qiov_inplace, qiov->niov);
               qemu_iovec_concat(&qiov_inplace, qiov, len,
                                 nb_sectors << BDRV_SECTOR_BITS);
               ret = bdrv_writev(bs, sector_num, &qiov_inplace);
               qemu_iovec_destroy(&qiov_inplace);
               if (ret < 0) {
                   return ret;
+              }
               sector_num += nb_sectors;
               len = nb_sectors << BDRV_SECTOR_BITS;
               count -= len;
+          }
           /* add data from the last sector */
           if (count > 0) {
               if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
                   return ret;
               qemu_iovec_to_buf(qiov, qiov->size - count, tmp_buf, count);
               if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0)
                   return ret;
+          }
           return qiov->size;
+      }
       int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
                       const void *buf, int count1)
+      {
           QEMUIOVector qiov;
           struct iovec iov = {
               .iov_base   = (void *) buf,
               .iov_len    = count1,
           };
           qemu_iovec_init_external(&qiov, &iov, 1);
           return bdrv_pwritev(bs, offset, &qiov);
+      }
       /*
        * Writes to the file and ensures that no writes are reordered across this
        * request (acts as a barrier)
+       *
        * Returns 0 on success, -errno in error cases.
        */
       int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
           const void *buf, int count)
+      {
           int ret;
           ret = bdrv_pwrite(bs, offset, buf, count);
           if (ret < 0) {
               return ret;
+          }
           /* No flush needed for cache modes that already do it */
           if (bs->enable_write_cache) {
               bdrv_flush(bs);
+          }
           return 0;
+      }
       static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs,
               int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
+      {
           /* Perform I/O through a temporary buffer so that users who scribble over
            * their read buffer while the operation is in progress do not end up
            * modifying the image file.  This is critical for zero-copy guest I/O
            * where anything might happen inside guest memory.
            */
           void *bounce_buffer;
           BlockDriver *drv = bs->drv;
           struct iovec iov;
           QEMUIOVector bounce_qiov;
           int64_t cluster_sector_num;
           int cluster_nb_sectors;
           size_t skip_bytes;
           int ret;
           /* Cover entire cluster so no additional backing file I/O is required when
            * allocating cluster in the image file.
            */
           bdrv_round_to_clusters(bs, sector_num, nb_sectors,
                                  &cluster_sector_num, &cluster_nb_sectors);
           trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors,
                                          cluster_sector_num, cluster_nb_sectors);
           iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE;
           iov.iov_base = bounce_buffer = qemu_blockalign(bs, iov.iov_len);
           qemu_iovec_init_external(&bounce_qiov, &iov, 1);
           ret = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors,
                                    &bounce_qiov);
           if (ret < 0) {
               goto err;
+          }
           if (drv->bdrv_co_write_zeroes &&
               buffer_is_zero(bounce_buffer, iov.iov_len)) {
               ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num,
                                             cluster_nb_sectors, 0);
           } else {
               /* This does not change the data on the disk, it is not necessary
                * to flush even in cache=writethrough mode.
                */
               ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors,
                                         &bounce_qiov);
+          }
           if (ret < 0) {
               /* It might be okay to ignore write errors for guest requests.  If this
                * is a deliberate copy-on-read then we don't want to ignore the error.
                * Simply report it in all cases.
                */
               goto err;
+          }
           skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE;
           qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes,
                               nb_sectors * BDRV_SECTOR_SIZE);
       err:
           qemu_vfree(bounce_buffer);
           return ret;
+      }
       /*
        * Forwards an already correctly aligned request to the BlockDriver. This
        * handles copy on read and zeroing after EOF; any other features must be
        * implemented by the caller.
        */
       static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
           BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
           int64_t align, QEMUIOVector *qiov, int flags)
+      {
           BlockDriver *drv = bs->drv;
           int ret;
           int64_t sector_num = offset >> BDRV_SECTOR_BITS;
           unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
           assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
           assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
           /* Handle Copy on Read and associated serialisation */
           if (flags & BDRV_REQ_COPY_ON_READ) {
               /* If we touch the same cluster it counts as an overlap.  This
                * guarantees that allocating writes will be serialized and not race
                * with each other for the same cluster.  For example, in copy-on-read
                * it ensures that the CoR read and write operations are atomic and
                * guest writes cannot interleave between them. */
               mark_request_serialising(req, bdrv_get_cluster_size(bs));
+          }
           wait_serialising_requests(req);
           if (flags & BDRV_REQ_COPY_ON_READ) {
               int pnum;
               ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum);
               if (ret < 0) {
                   goto out;
+              }
               if (!ret || pnum != nb_sectors) {
                   ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov);
                   goto out;
+              }
+          }
           /* Forward the request to the BlockDriver */
           if (!(bs->zero_beyond_eof && bs->growable)) {
               ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
           } else {
               /* Read zeros after EOF of growable BDSes */
               int64_t len, total_sectors, max_nb_sectors;
               len = bdrv_getlength(bs);
               if (len < 0) {
                   ret = len;
                   goto out;
+              }
               total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE);
               max_nb_sectors = MAX(0, ROUND_UP(total_sectors - sector_num,
                                                align >> BDRV_SECTOR_BITS));
               if (max_nb_sectors > 0) {
                   ret = drv->bdrv_co_readv(bs, sector_num,
                                            MIN(nb_sectors, max_nb_sectors), qiov);
               } else {
                   ret = 0;
+              }
               /* Reading beyond end of file is supposed to produce zeroes */
               if (ret == 0 && total_sectors < sector_num + nb_sectors) {
                   uint64_t offset = MAX(0, total_sectors - sector_num);
                   uint64_t bytes = (sector_num + nb_sectors - offset) *
                                     BDRV_SECTOR_SIZE;
                   qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes);
+              }
+          }
       out:
           return ret;
+      }
       /*
        * Handle a read request in coroutine context
        */
       static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
           int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
           BdrvRequestFlags flags)
+      {
           BlockDriver *drv = bs->drv;
           BdrvTrackedRequest req;
           /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
           uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment);
           uint8_t *head_buf = NULL;
           uint8_t *tail_buf = NULL;
           QEMUIOVector local_qiov;
           bool use_local_qiov = false;
           int ret;
           if (!drv) {
               return -ENOMEDIUM;
+          }
           if (bdrv_check_byte_request(bs, offset, bytes)) {
               return -EIO;
+          }
           if (bs->copy_on_read) {
               flags |= BDRV_REQ_COPY_ON_READ;
+          }
           /* throttling disk I/O */
           if (bs->io_limits_enabled) {
               /* TODO Switch to byte granularity */
               bdrv_io_limits_intercept(bs, bytes >> BDRV_SECTOR_BITS, false);
+          }
           /* Align read if necessary by padding qiov */
           if (offset & (align - 1)) {
               head_buf = qemu_blockalign(bs, align);
               qemu_iovec_init(&local_qiov, qiov->niov + 2);
               qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
               qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
               use_local_qiov = true;
               bytes += offset & (align - 1);
               offset = offset & ~(align - 1);
+          }
           if ((offset + bytes) & (align - 1)) {
               if (!use_local_qiov) {
                   qemu_iovec_init(&local_qiov, qiov->niov + 1);
                   qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
                   use_local_qiov = true;
+              }
               tail_buf = qemu_blockalign(bs, align);
               qemu_iovec_add(&local_qiov, tail_buf,
                              align - ((offset + bytes) & (align - 1)));
               bytes = ROUND_UP(bytes, align);
+          }
           tracked_request_begin(&req, bs, offset, bytes, false);
           ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align,
                                     use_local_qiov ? &local_qiov : qiov,
                                     flags);
           tracked_request_end(&req);
           if (use_local_qiov) {
               qemu_iovec_destroy(&local_qiov);
               qemu_vfree(head_buf);
               qemu_vfree(tail_buf);
+          }
           return ret;
+      }
       static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
           int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
           BdrvRequestFlags flags)
+      {
           if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) {
               return -EINVAL;
+          }
           return bdrv_co_do_preadv(bs, sector_num << BDRV_SECTOR_BITS,
                                    nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
+      }
       int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
           int nb_sectors, QEMUIOVector *qiov)
+      {
           trace_bdrv_co_readv(bs, sector_num, nb_sectors);
           return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0);
+      }
       int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
           int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
+      {
           trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors);
           return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov,
                                   BDRV_REQ_COPY_ON_READ);
+      }
       /* if no limit is specified in the BlockLimits use a default
        * of 32768 512-byte sectors (16 MiB) per request.
        */
       #define MAX_WRITE_ZEROES_DEFAULT 32768
       static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
           int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
+      {
           BlockDriver *drv = bs->drv;
           QEMUIOVector qiov;
           struct iovec iov = {0};
           int ret = 0;
           int max_write_zeroes = bs->bl.max_write_zeroes ?
                                  bs->bl.max_write_zeroes : MAX_WRITE_ZEROES_DEFAULT;
           while (nb_sectors > 0 && !ret) {
               int num = nb_sectors;
               /* Align request.  Block drivers can expect the "bulk" of the request
                * to be aligned.
                */
               if (bs->bl.write_zeroes_alignment
                   && num > bs->bl.write_zeroes_alignment) {
                   if (sector_num % bs->bl.write_zeroes_alignment != 0) {
                       /* Make a small request up to the first aligned sector.  */
                       num = bs->bl.write_zeroes_alignment;
                       num -= sector_num % bs->bl.write_zeroes_alignment;
                   } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) {
                       /* Shorten the request to the last aligned sector.  num cannot
                        * underflow because num > bs->bl.write_zeroes_alignment.
                        */
                       num -= (sector_num + num) % bs->bl.write_zeroes_alignment;
+                  }
+              }
               /* limit request size */
               if (num > max_write_zeroes) {
                   num = max_write_zeroes;
+              }
               ret = -ENOTSUP;
               /* First try the efficient write zeroes operation */
               if (drv->bdrv_co_write_zeroes) {
                   ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags);
+              }
               if (ret == -ENOTSUP) {
                   /* Fall back to bounce buffer if write zeroes is unsupported */
                   iov.iov_len = num * BDRV_SECTOR_SIZE;
                   if (iov.iov_base == NULL) {
                       iov.iov_base = qemu_blockalign(bs, num * BDRV_SECTOR_SIZE);
                       memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE);
+                  }
                   qemu_iovec_init_external(&qiov, &iov, 1);
                   ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov);
                   /* Keep bounce buffer around if it is big enough for all
                    * all future requests.
                    */
                   if (num < max_write_zeroes) {
                       qemu_vfree(iov.iov_base);
                       iov.iov_base = NULL;
+                  }
+              }
               sector_num += num;
               nb_sectors -= num;
+          }
           qemu_vfree(iov.iov_base);
           return ret;
+      }
       /*
        * Forwards an already correctly aligned write request to the BlockDriver.
        */
       static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
           BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
           QEMUIOVector *qiov, int flags)
+      {
           BlockDriver *drv = bs->drv;
           int ret;
           int64_t sector_num = offset >> BDRV_SECTOR_BITS;
           unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
           assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
           assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
           wait_serialising_requests(req);
           ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req);
           if (ret < 0) {
               /* Do nothing, write notifier decided to fail this request */
           } else if (flags & BDRV_REQ_ZERO_WRITE) {
               ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags);
           } else {
               ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
+          }
           if (ret == 0 && !bs->enable_write_cache) {
               ret = bdrv_co_flush(bs);
+          }
           bdrv_set_dirty(bs, sector_num, nb_sectors);
           if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
               bs->wr_highest_sector = sector_num + nb_sectors - 1;
+          }
           if (bs->growable && ret >= 0) {
               bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors);
+          }
           return ret;
+      }
       /*
        * Handle a write request in coroutine context
        */
       static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
           int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
           BdrvRequestFlags flags)
+      {
           BdrvTrackedRequest req;
           int ret;
           if (!bs->drv) {
               return -ENOMEDIUM;
+          }
           if (bs->read_only) {
               return -EACCES;
+          }
           if (bdrv_check_byte_request(bs, offset, bytes)) {
               return -EIO;
+          }
           /* throttling disk I/O */
           if (bs->io_limits_enabled) {
               /* TODO Switch to byte granularity */
               bdrv_io_limits_intercept(bs, bytes >> BDRV_SECTOR_BITS, true);
+          }
           tracked_request_begin(&req, bs, offset, bytes, true);
           ret = bdrv_aligned_pwritev(bs, &req, offset, bytes, qiov, flags);
           tracked_request_end(&req);
           return ret;
+      }
       static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
           int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
           BdrvRequestFlags flags)
+      {
           if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) {
               return -EINVAL;
+          }
           return bdrv_co_do_pwritev(bs, sector_num << BDRV_SECTOR_BITS,
                                     nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
+      }
       int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
           int nb_sectors, QEMUIOVector *qiov)
+      {
           trace_bdrv_co_writev(bs, sector_num, nb_sectors);
           return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0);
+      }
       int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs,
                                             int64_t sector_num, int nb_sectors,
                                             BdrvRequestFlags flags)
+      {
           trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags);
           if (!(bs->open_flags & BDRV_O_UNMAP)) {
               flags &= ~BDRV_REQ_MAY_UNMAP;
+          }
           return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL,
                                    BDRV_REQ_ZERO_WRITE | flags);
+      }
       /**
        * Truncate file to 'offset' bytes (needed only for file protocols)
        */
       int bdrv_truncate(BlockDriverState *bs, int64_t offset)
+      {
           BlockDriver *drv = bs->drv;
           int ret;
           if (!drv)
               return -ENOMEDIUM;
           if (!drv->bdrv_truncate)
               return -ENOTSUP;
           if (bs->read_only)
               return -EACCES;
           if (bdrv_in_use(bs))
               return -EBUSY;
           ret = drv->bdrv_truncate(bs, offset);
           if (ret == 0) {
               ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
               bdrv_dev_resize_cb(bs);
+          }
           return ret;
+      }
       /**
        * Length of a allocated file in bytes. Sparse files are counted by actual
        * allocated space. Return < 0 if error or unknown.
        */
       int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
+      {
           BlockDriver *drv = bs->drv;
           if (!drv) {
               return -ENOMEDIUM;
+          }
           if (drv->bdrv_get_allocated_file_size) {
               return drv->bdrv_get_allocated_file_size(bs);
+          }
           if (bs->file) {
               return bdrv_get_allocated_file_size(bs->file);
+          }
           return -ENOTSUP;
+      }
       /**
        * Length of a file in bytes. Return < 0 if error or unknown.
        */
       int64_t bdrv_getlength(BlockDriverState *bs)
+      {
           BlockDriver *drv = bs->drv;
           if (!drv)
               return -ENOMEDIUM;
           if (drv->has_variable_length) {
               int ret = refresh_total_sectors(bs, bs->total_sectors);
               if (ret < 0) {
                   return ret;
+              }
+          }
           return bs->total_sectors * BDRV_SECTOR_SIZE;
+      }
       /* return 0 as number of sectors if no device present or error */
       void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
+      {
           int64_t length;
           length = bdrv_getlength(bs);
           if (length < 0)
               length = 0;
           else
               length = length >> BDRV_SECTOR_BITS;
           *nb_sectors_ptr = length;
+      }
       void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error,
                              BlockdevOnError on_write_error)
+      {
           bs->on_read_error = on_read_error;
           bs->on_write_error = on_write_error;
+      }
       BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read)
+      {
           return is_read ? bs->on_read_error : bs->on_write_error;
+      }
       BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, bool is_read, int error)
+      {
           BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error;
           switch (on_err) {
           case BLOCKDEV_ON_ERROR_ENOSPC:
               return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT;
           case BLOCKDEV_ON_ERROR_STOP:
               return BDRV_ACTION_STOP;
           case BLOCKDEV_ON_ERROR_REPORT:
               return BDRV_ACTION_REPORT;
           case BLOCKDEV_ON_ERROR_IGNORE:
               return BDRV_ACTION_IGNORE;
           default:
               abort();
+          }
+      }
       /* This is done by device models because, while the block layer knows
        * about the error, it does not know whether an operation comes from
        * the device or the block layer (from a job, for example).
        */
       void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action,
                              bool is_read, int error)
+      {
           assert(error >= 0);
           bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read);
           if (action == BDRV_ACTION_STOP) {
               vm_stop(RUN_STATE_IO_ERROR);
               bdrv_iostatus_set_err(bs, error);
+          }
+      }
       int bdrv_is_read_only(BlockDriverState *bs)
+      {
           return bs->read_only;
+      }
       int bdrv_is_sg(BlockDriverState *bs)
+      {
           return bs->sg;
+      }
       int bdrv_enable_write_cache(BlockDriverState *bs)
+      {
           return bs->enable_write_cache;
+      }
       void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce)
+      {
           bs->enable_write_cache = wce;
           /* so a reopen() will preserve wce */
           if (wce) {
               bs->open_flags |= BDRV_O_CACHE_WB;
           } else {
               bs->open_flags &= ~BDRV_O_CACHE_WB;
+          }
+      }
       int bdrv_is_encrypted(BlockDriverState *bs)
+      {
           if (bs->backing_hd && bs->backing_hd->encrypted)
               return 1;
           return bs->encrypted;
+      }
       int bdrv_key_required(BlockDriverState *bs)
+      {
           BlockDriverState *backing_hd = bs->backing_hd;
           if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key)
               return 1;
           return (bs->encrypted && !bs->valid_key);
+      }
       int bdrv_set_key(BlockDriverState *bs, const char *key)
+      {
           int ret;
           if (bs->backing_hd && bs->backing_hd->encrypted) {
               ret = bdrv_set_key(bs->backing_hd, key);
               if (ret < 0)
                   return ret;
               if (!bs->encrypted)
                   return 0;
+          }
           if (!bs->encrypted) {
               return -EINVAL;
           } else if (!bs->drv || !bs->drv->bdrv_set_key) {
               return -ENOMEDIUM;
+          }
           ret = bs->drv->bdrv_set_key(bs, key);
           if (ret < 0) {
               bs->valid_key = 0;
           } else if (!bs->valid_key) {
               bs->valid_key = 1;
               /* call the change callback now, we skipped it on open */
               bdrv_dev_change_media_cb(bs, true);
+          }
           return ret;
+      }
       const char *bdrv_get_format_name(BlockDriverState *bs)
+      {
           return bs->drv ? bs->drv->format_name : NULL;
+      }
       void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
                                void *opaque)
+      {
           BlockDriver *drv;
           QLIST_FOREACH(drv, &bdrv_drivers, list) {
               it(opaque, drv->format_name);
+          }
+      }
       /* This function is to find block backend bs */
       BlockDriverState *bdrv_find(const char *name)
+      {
           BlockDriverState *bs;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               if (!strcmp(name, bs->device_name)) {
                   return bs;
+              }
+          }
           return NULL;
+      }
       /* This function is to find a node in the bs graph */
       BlockDriverState *bdrv_find_node(const char *node_name)
+      {
           BlockDriverState *bs;
           assert(node_name);
           QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
               if (!strcmp(node_name, bs->node_name)) {
                   return bs;
+              }
+          }
           return NULL;
+      }
       /* Put this QMP function here so it can access the static graph_bdrv_states. */
       BlockDeviceInfoList *bdrv_named_nodes_list(void)
+      {
           BlockDeviceInfoList *list, *entry;
           BlockDriverState *bs;
           list = NULL;
           QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
               entry = g_malloc0(sizeof(*entry));
               entry->value = bdrv_block_device_info(bs);
               entry->next = list;
               list = entry;
+          }
           return list;
+      }
       BlockDriverState *bdrv_lookup_bs(const char *device,
                                        const char *node_name,
                                        Error **errp)
+      {
           BlockDriverState *bs = NULL;
           if ((!device && !node_name) || (device && node_name)) {
               error_setg(errp, "Use either device or node-name but not both");
               return NULL;
+          }
           if (device) {
               bs = bdrv_find(device);
               if (!bs) {
                   error_set(errp, QERR_DEVICE_NOT_FOUND, device);
                   return NULL;
+              }
               return bs;
+          }
           bs = bdrv_find_node(node_name);
           if (!bs) {
               error_set(errp, QERR_DEVICE_NOT_FOUND, node_name);
               return NULL;
+          }
           return bs;
+      }
       BlockDriverState *bdrv_next(BlockDriverState *bs)
+      {
           if (!bs) {
               return QTAILQ_FIRST(&bdrv_states);
+          }
           return QTAILQ_NEXT(bs, device_list);
+      }
       void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque)
+      {
           BlockDriverState *bs;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               it(opaque, bs);
+          }
+      }
       const char *bdrv_get_device_name(BlockDriverState *bs)
+      {
           return bs->device_name;
+      }
       int bdrv_get_flags(BlockDriverState *bs)
+      {
           return bs->open_flags;
+      }
       int bdrv_flush_all(void)
+      {
           BlockDriverState *bs;
           int result = 0;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               int ret = bdrv_flush(bs);
               if (ret < 0 && !result) {
                   result = ret;
+              }
+          }
           return result;
+      }
       int bdrv_has_zero_init_1(BlockDriverState *bs)
+      {
           return 1;
+      }
       int bdrv_has_zero_init(BlockDriverState *bs)
+      {
           assert(bs->drv);
           /* If BS is a copy on write image, it is initialized to
              the contents of the base image, which may not be zeroes.  */
           if (bs->backing_hd) {
               return 0;
+          }
           if (bs->drv->bdrv_has_zero_init) {
               return bs->drv->bdrv_has_zero_init(bs);
+          }
           /* safe default */
           return 0;
+      }
       bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
+      {
           BlockDriverInfo bdi;
           if (bs->backing_hd) {
               return false;
+          }
           if (bdrv_get_info(bs, &bdi) == 0) {
               return bdi.unallocated_blocks_are_zero;
+          }
           return false;
+      }
       bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
+      {
           BlockDriverInfo bdi;
           if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) {
               return false;
+          }
           if (bdrv_get_info(bs, &bdi) == 0) {
               return bdi.can_write_zeroes_with_unmap;
+          }
           return false;
+      }
       typedef struct BdrvCoGetBlockStatusData {
           BlockDriverState *bs;
           BlockDriverState *base;
           int64_t sector_num;
           int nb_sectors;
           int *pnum;
           int64_t ret;
           bool done;
       } BdrvCoGetBlockStatusData;
       /*
        * Returns true iff the specified sector is present in the disk image. Drivers
        * not implementing the functionality are assumed to not support backing files,
        * hence all their sectors are reported as allocated.
+       *
        * If 'sector_num' is beyond the end of the disk image the return value is 0
        * and 'pnum' is set to 0.
+       *
        * 'pnum' is set to the number of sectors (including and immediately following
        * the specified sector) that are known to be in the same
        * allocated/unallocated state.
+       *
        * 'nb_sectors' is the max value 'pnum' should be set to.  If nb_sectors goes
        * beyond the end of the disk image it will be clamped.
        */
       static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
                                                            int64_t sector_num,
                                                            int nb_sectors, int *pnum)
+      {
           int64_t length;
           int64_t n;
           int64_t ret, ret2;
           length = bdrv_getlength(bs);
           if (length < 0) {
               return length;
+          }
           if (sector_num >= (length >> BDRV_SECTOR_BITS)) {
               *pnum = 0;
               return 0;
+          }
           n = bs->total_sectors - sector_num;
           if (n < nb_sectors) {
               nb_sectors = n;
+          }
           if (!bs->drv->bdrv_co_get_block_status) {
               *pnum = nb_sectors;
               ret = BDRV_BLOCK_DATA;
               if (bs->drv->protocol_name) {
                   ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);
+              }
               return ret;
+          }
           ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
           if (ret < 0) {
               *pnum = 0;
               return ret;
+          }
           if (ret & BDRV_BLOCK_RAW) {
               assert(ret & BDRV_BLOCK_OFFSET_VALID);
               return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
                                            *pnum, pnum);
+          }
           if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) {
               if (bdrv_unallocated_blocks_are_zero(bs)) {
                   ret |= BDRV_BLOCK_ZERO;
               } else if (bs->backing_hd) {
                   BlockDriverState *bs2 = bs->backing_hd;
                   int64_t length2 = bdrv_getlength(bs2);
                   if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) {
                       ret |= BDRV_BLOCK_ZERO;
+                  }
+              }
+          }
           if (bs->file &&
               (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
               (ret & BDRV_BLOCK_OFFSET_VALID)) {
               ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
                                               *pnum, pnum);
               if (ret2 >= 0) {
                   /* Ignore errors.  This is just providing extra information, it
                    * is useful but not necessary.
                    */
                   ret |= (ret2 & BDRV_BLOCK_ZERO);
+              }
+          }
           return ret;
+      }
       /* Coroutine wrapper for bdrv_get_block_status() */
       static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque)
+      {
           BdrvCoGetBlockStatusData *data = opaque;
           BlockDriverState *bs = data->bs;
           data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors,
                                                data->pnum);
           data->done = true;
+      }
       /*
        * Synchronous wrapper around bdrv_co_get_block_status().
+       *
        * See bdrv_co_get_block_status() for details.
        */
       int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
                                     int nb_sectors, int *pnum)
+      {
           Coroutine *co;
           BdrvCoGetBlockStatusData data = {
               .bs = bs,
               .sector_num = sector_num,
               .nb_sectors = nb_sectors,
               .pnum = pnum,
               .done = false,
           };
           if (qemu_in_coroutine()) {
               /* Fast-path if already in coroutine context */
               bdrv_get_block_status_co_entry(&data);
           } else {
               co = qemu_coroutine_create(bdrv_get_block_status_co_entry);
               qemu_coroutine_enter(co, &data);
               while (!data.done) {
                   qemu_aio_wait();
+              }
+          }
           return data.ret;
+      }
       int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
                                          int nb_sectors, int *pnum)
+      {
           int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum);
           if (ret < 0) {
               return ret;
+          }
           return
               (ret & BDRV_BLOCK_DATA) ||
               ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs));
+      }
       /*
        * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
+       *
        * Return true if the given sector is allocated in any image between
        * BASE and TOP (inclusive).  BASE can be NULL to check if the given
        * sector is allocated in any image of the chain.  Return false otherwise.
+       *
        * 'pnum' is set to the number of sectors (including and immediately following
        *  the specified sector) that are known to be in the same
        *  allocated/unallocated state.
+       *
        */
       int bdrv_is_allocated_above(BlockDriverState *top,
                                   BlockDriverState *base,
                                   int64_t sector_num,
                                   int nb_sectors, int *pnum)
+      {
           BlockDriverState *intermediate;
           int ret, n = nb_sectors;
           intermediate = top;
           while (intermediate && intermediate != base) {
               int pnum_inter;
               ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors,
                                       &pnum_inter);
               if (ret < 0) {
                   return ret;
               } else if (ret) {
                   *pnum = pnum_inter;
                   return 1;
+              }
               /*
                * [sector_num, nb_sectors] is unallocated on top but intermediate
                * might have
+               *
                * [sector_num+x, nr_sectors] allocated.
                */
               if (n > pnum_inter &&
                   (intermediate == top ||
                    sector_num + pnum_inter < intermediate->total_sectors)) {
                   n = pnum_inter;
+              }
               intermediate = intermediate->backing_hd;
+          }
           *pnum = n;
           return 0;
+      }
       const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
+      {
           if (bs->backing_hd && bs->backing_hd->encrypted)
               return bs->backing_file;
           else if (bs->encrypted)
               return bs->filename;
           else
               return NULL;
+      }
       void bdrv_get_backing_filename(BlockDriverState *bs,
                                      char *filename, int filename_size)
+      {
           pstrcpy(filename, filename_size, bs->backing_file);
+      }
       int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
                                 const uint8_t *buf, int nb_sectors)
+      {
           BlockDriver *drv = bs->drv;
           if (!drv)
               return -ENOMEDIUM;
           if (!drv->bdrv_write_compressed)
               return -ENOTSUP;
           if (bdrv_check_request(bs, sector_num, nb_sectors))
               return -EIO;
           assert(QLIST_EMPTY(&bs->dirty_bitmaps));
           return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
+      }
       int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+      {
           BlockDriver *drv = bs->drv;
           if (!drv)
               return -ENOMEDIUM;
           if (!drv->bdrv_get_info)
               return -ENOTSUP;
           memset(bdi, 0, sizeof(*bdi));
           return drv->bdrv_get_info(bs, bdi);
+      }
       ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
+      {
           BlockDriver *drv = bs->drv;
           if (drv && drv->bdrv_get_specific_info) {
               return drv->bdrv_get_specific_info(bs);
+          }
           return NULL;
+      }
       int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
                             int64_t pos, int size)
+      {
           QEMUIOVector qiov;
           struct iovec iov = {
               .iov_base   = (void *) buf,
               .iov_len    = size,
           };
           qemu_iovec_init_external(&qiov, &iov, 1);
           return bdrv_writev_vmstate(bs, &qiov, pos);
+      }
       int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
+      {
           BlockDriver *drv = bs->drv;
           if (!drv) {
               return -ENOMEDIUM;
           } else if (drv->bdrv_save_vmstate) {
               return drv->bdrv_save_vmstate(bs, qiov, pos);
           } else if (bs->file) {
               return bdrv_writev_vmstate(bs->file, qiov, pos);
+          }
           return -ENOTSUP;
+      }
       int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
                             int64_t pos, int size)
+      {
           BlockDriver *drv = bs->drv;
           if (!drv)
               return -ENOMEDIUM;
           if (drv->bdrv_load_vmstate)
               return drv->bdrv_load_vmstate(bs, buf, pos, size);
           if (bs->file)
               return bdrv_load_vmstate(bs->file, buf, pos, size);
           return -ENOTSUP;
+      }
       void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event)
+      {
           if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
               return;
+          }
           bs->drv->bdrv_debug_event(bs, event);
+      }
       int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
                                 const char *tag)
+      {
           while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
               bs = bs->file;
+          }
           if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
               return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
+          }
           return -ENOTSUP;
+      }
       int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
+      {
           while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
               bs = bs->file;
+          }
           if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
               return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
+          }
           return -ENOTSUP;
+      }
       int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
+      {
           while (bs && bs->drv && !bs->drv->bdrv_debug_resume) {
               bs = bs->file;
+          }
           if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
               return bs->drv->bdrv_debug_resume(bs, tag);
+          }
           return -ENOTSUP;
+      }
       bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
+      {
           while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
               bs = bs->file;
+          }
           if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
               return bs->drv->bdrv_debug_is_suspended(bs, tag);
+          }
           return false;
+      }
       int bdrv_is_snapshot(BlockDriverState *bs)
+      {
           return !!(bs->open_flags & BDRV_O_SNAPSHOT);
+      }
       /* backing_file can either be relative, or absolute, or a protocol.  If it is
        * relative, it must be relative to the chain.  So, passing in bs->filename
        * from a BDS as backing_file should not be done, as that may be relative to
        * the CWD rather than the chain. */
       BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
               const char *backing_file)
+      {
           char *filename_full = NULL;
           char *backing_file_full = NULL;
           char *filename_tmp = NULL;
           int is_protocol = 0;
           BlockDriverState *curr_bs = NULL;
           BlockDriverState *retval = NULL;
           if (!bs || !bs->drv || !backing_file) {
               return NULL;
+          }
           filename_full     = g_malloc(PATH_MAX);
           backing_file_full = g_malloc(PATH_MAX);
           filename_tmp      = g_malloc(PATH_MAX);
           is_protocol = path_has_protocol(backing_file);
           for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) {
               /* If either of the filename paths is actually a protocol, then
                * compare unmodified paths; otherwise make paths relative */
               if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
                   if (strcmp(backing_file, curr_bs->backing_file) == 0) {
                       retval = curr_bs->backing_hd;
                       break;
+                  }
               } else {
                   /* If not an absolute filename path, make it relative to the current
                    * image's filename path */
                   path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
                                backing_file);
                   /* We are going to compare absolute pathnames */
                   if (!realpath(filename_tmp, filename_full)) {
                       continue;
+                  }
                   /* We need to make sure the backing filename we are comparing against
                    * is relative to the current image filename (or absolute) */
                   path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
                                curr_bs->backing_file);
                   if (!realpath(filename_tmp, backing_file_full)) {
                       continue;
+                  }
                   if (strcmp(backing_file_full, filename_full) == 0) {
                       retval = curr_bs->backing_hd;
                       break;
+                  }
+              }
+          }
           g_free(filename_full);
           g_free(backing_file_full);
           g_free(filename_tmp);
           return retval;
+      }
       int bdrv_get_backing_file_depth(BlockDriverState *bs)
+      {
           if (!bs->drv) {
               return 0;
+          }
           if (!bs->backing_hd) {
               return 0;
+          }
           return 1 + bdrv_get_backing_file_depth(bs->backing_hd);
+      }
       BlockDriverState *bdrv_find_base(BlockDriverState *bs)
+      {
           BlockDriverState *curr_bs = NULL;
           if (!bs) {
               return NULL;
+          }
           curr_bs = bs;
           while (curr_bs->backing_hd) {
               curr_bs = curr_bs->backing_hd;
+          }
           return curr_bs;
+      }
       /**************************************************************/
       /* async I/Os */
       BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
                                        QEMUIOVector *qiov, int nb_sectors,
                                        BlockDriverCompletionFunc *cb, void *opaque)
+      {
           trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque);
           return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0,
                                        cb, opaque, false);
+      }
       BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
                                         QEMUIOVector *qiov, int nb_sectors,
                                         BlockDriverCompletionFunc *cb, void *opaque)
+      {
           trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque);
           return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0,
                                        cb, opaque, true);
+      }
       BlockDriverAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs,
               int64_t sector_num, int nb_sectors, BdrvRequestFlags flags,
               BlockDriverCompletionFunc *cb, void *opaque)
+      {
           trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque);
           return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors,
                                        BDRV_REQ_ZERO_WRITE | flags,
                                        cb, opaque, true);
+      }
       typedef struct MultiwriteCB {
           int error;
           int num_requests;
           int num_callbacks;
           struct {
               BlockDriverCompletionFunc *cb;
               void *opaque;
               QEMUIOVector *free_qiov;
           } callbacks[];
       } MultiwriteCB;
       static void multiwrite_user_cb(MultiwriteCB *mcb)
+      {
           int i;
           for (i = 0; i < mcb->num_callbacks; i++) {
               mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error);
               if (mcb->callbacks[i].free_qiov) {
                   qemu_iovec_destroy(mcb->callbacks[i].free_qiov);
+              }
               g_free(mcb->callbacks[i].free_qiov);
+          }
+      }
       static void multiwrite_cb(void *opaque, int ret)
+      {
           MultiwriteCB *mcb = opaque;
           trace_multiwrite_cb(mcb, ret);
           if (ret < 0 && !mcb->error) {
               mcb->error = ret;
+          }
           mcb->num_requests--;
           if (mcb->num_requests == 0) {
               multiwrite_user_cb(mcb);
               g_free(mcb);
+          }
+      }
       static int multiwrite_req_compare(const void *a, const void *b)
+      {
           const BlockRequest *req1 = a, *req2 = b;
           /*
            * Note that we can't simply subtract req2->sector from req1->sector
            * here as that could overflow the return value.
            */
           if (req1->sector > req2->sector) {
               return 1;
           } else if (req1->sector < req2->sector) {
               return -1;
           } else {
               return 0;
+          }
+      }
       /*
        * Takes a bunch of requests and tries to merge them. Returns the number of
        * requests that remain after merging.
        */
       static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs,
           int num_reqs, MultiwriteCB *mcb)
+      {
           int i, outidx;
           // Sort requests by start sector
           qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare);
           // Check if adjacent requests touch the same clusters. If so, combine them,
           // filling up gaps with zero sectors.
           outidx = 0;
           for (i = 1; i < num_reqs; i++) {
               int merge = 0;
               int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors;
               // Handle exactly sequential writes and overlapping writes.
               if (reqs[i].sector <= oldreq_last) {
                   merge = 1;
+              }
               if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) {
                   merge = 0;
+              }
               if (merge) {
                   size_t size;
                   QEMUIOVector *qiov = g_malloc0(sizeof(*qiov));
                   qemu_iovec_init(qiov,
                       reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1);
                   // Add the first request to the merged one. If the requests are
                   // overlapping, drop the last sectors of the first request.
                   size = (reqs[i].sector - reqs[outidx].sector) << 9;
                   qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size);
                   // We should need to add any zeros between the two requests
                   assert (reqs[i].sector <= oldreq_last);
                   // Add the second request
                   qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size);
                   reqs[outidx].nb_sectors = qiov->size >> 9;
                   reqs[outidx].qiov = qiov;
                   mcb->callbacks[i].free_qiov = reqs[outidx].qiov;
               } else {
                   outidx++;
                   reqs[outidx].sector     = reqs[i].sector;
                   reqs[outidx].nb_sectors = reqs[i].nb_sectors;
                   reqs[outidx].qiov       = reqs[i].qiov;
+              }
+          }
           return outidx + 1;
+      }
       /*
        * Submit multiple AIO write requests at once.
+       *
        * On success, the function returns 0 and all requests in the reqs array have
        * been submitted. In error case this function returns -1, and any of the
        * requests may or may not be submitted yet. In particular, this means that the
        * callback will be called for some of the requests, for others it won't. The
        * caller must check the error field of the BlockRequest to wait for the right
        * callbacks (if error != 0, no callback will be called).
+       *
        * The implementation may modify the contents of the reqs array, e.g. to merge
        * requests. However, the fields opaque and error are left unmodified as they
        * are used to signal failure for a single request to the caller.
        */
       int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs)
+      {
           MultiwriteCB *mcb;
           int i;
           /* don't submit writes if we don't have a medium */
           if (bs->drv == NULL) {
               for (i = 0; i < num_reqs; i++) {
                   reqs[i].error = -ENOMEDIUM;
+              }
               return -1;
+          }
           if (num_reqs == 0) {
               return 0;
+          }
           // Create MultiwriteCB structure
           mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks));
           mcb->num_requests = 0;
           mcb->num_callbacks = num_reqs;
           for (i = 0; i < num_reqs; i++) {
               mcb->callbacks[i].cb = reqs[i].cb;
               mcb->callbacks[i].opaque = reqs[i].opaque;
+          }
           // Check for mergable requests
           num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb);
           trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs);
           /* Run the aio requests. */
           mcb->num_requests = num_reqs;
           for (i = 0; i < num_reqs; i++) {
               bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov,
                                     reqs[i].nb_sectors, reqs[i].flags,
                                     multiwrite_cb, mcb,
                                     true);
+          }
           return 0;
+      }
       void bdrv_aio_cancel(BlockDriverAIOCB *acb)
+      {
           acb->aiocb_info->cancel(acb);
+      }
       /**************************************************************/
       /* async block device emulation */
       typedef struct BlockDriverAIOCBSync {
           BlockDriverAIOCB common;
           QEMUBH *bh;
           int ret;
           /* vector translation state */
           QEMUIOVector *qiov;
           uint8_t *bounce;
           int is_write;
       } BlockDriverAIOCBSync;
       static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb)
+      {
           BlockDriverAIOCBSync *acb =
               container_of(blockacb, BlockDriverAIOCBSync, common);
           qemu_bh_delete(acb->bh);
           acb->bh = NULL;
           qemu_aio_release(acb);
+      }
       static const AIOCBInfo bdrv_em_aiocb_info = {
           .aiocb_size         = sizeof(BlockDriverAIOCBSync),
           .cancel             = bdrv_aio_cancel_em,
       };
       static void bdrv_aio_bh_cb(void *opaque)
+      {
           BlockDriverAIOCBSync *acb = opaque;
           if (!acb->is_write)
               qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
           qemu_vfree(acb->bounce);
           acb->common.cb(acb->common.opaque, acb->ret);
           qemu_bh_delete(acb->bh);
           acb->bh = NULL;
           qemu_aio_release(acb);
+      }
       static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs,
                                                   int64_t sector_num,
                                                   QEMUIOVector *qiov,
                                                   int nb_sectors,
                                                   BlockDriverCompletionFunc *cb,
                                                   void *opaque,
                                                   int is_write)
+      {
           BlockDriverAIOCBSync *acb;
           acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque);
           acb->is_write = is_write;
           acb->qiov = qiov;
           acb->bounce = qemu_blockalign(bs, qiov->size);
           acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
           if (is_write) {
               qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
               acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors);
           } else {
               acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors);
+          }
           qemu_bh_schedule(acb->bh);
           return &acb->common;
+      }
       static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
               int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
               BlockDriverCompletionFunc *cb, void *opaque)
+      {
           return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
+      }
       static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
               int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
               BlockDriverCompletionFunc *cb, void *opaque)
+      {
           return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
+      }
       typedef struct BlockDriverAIOCBCoroutine {
           BlockDriverAIOCB common;
           BlockRequest req;
           bool is_write;
           bool *done;
           QEMUBH* bh;
       } BlockDriverAIOCBCoroutine;
       static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb)
+      {
           BlockDriverAIOCBCoroutine *acb =
               container_of(blockacb, BlockDriverAIOCBCoroutine, common);
           bool done = false;
           acb->done = &done;
           while (!done) {
               qemu_aio_wait();
+          }
+      }
       static const AIOCBInfo bdrv_em_co_aiocb_info = {
           .aiocb_size         = sizeof(BlockDriverAIOCBCoroutine),
           .cancel             = bdrv_aio_co_cancel_em,
       };
       static void bdrv_co_em_bh(void *opaque)
+      {
           BlockDriverAIOCBCoroutine *acb = opaque;
           acb->common.cb(acb->common.opaque, acb->req.error);
           if (acb->done) {
               *acb->done = true;
+          }
           qemu_bh_delete(acb->bh);
           qemu_aio_release(acb);
+      }
       /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */
       static void coroutine_fn bdrv_co_do_rw(void *opaque)
+      {
           BlockDriverAIOCBCoroutine *acb = opaque;
           BlockDriverState *bs = acb->common.bs;
           if (!acb->is_write) {
               acb->req.error = bdrv_co_do_readv(bs, acb->req.sector,
                   acb->req.nb_sectors, acb->req.qiov, acb->req.flags);
           } else {
               acb->req.error = bdrv_co_do_writev(bs, acb->req.sector,
                   acb->req.nb_sectors, acb->req.qiov, acb->req.flags);
+          }
           acb->bh = qemu_bh_new(bdrv_co_em_bh, acb);
           qemu_bh_schedule(acb->bh);
+      }
       static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
                                                      int64_t sector_num,
                                                      QEMUIOVector *qiov,
                                                      int nb_sectors,
                                                      BdrvRequestFlags flags,
                                                      BlockDriverCompletionFunc *cb,
                                                      void *opaque,
                                                      bool is_write)
+      {
           Coroutine *co;
           BlockDriverAIOCBCoroutine *acb;
           acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
           acb->req.sector = sector_num;
           acb->req.nb_sectors = nb_sectors;
           acb->req.qiov = qiov;
           acb->req.flags = flags;
           acb->is_write = is_write;
           acb->done = NULL;
           co = qemu_coroutine_create(bdrv_co_do_rw);
           qemu_coroutine_enter(co, acb);
           return &acb->common;
+      }
       static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque)
+      {
           BlockDriverAIOCBCoroutine *acb = opaque;
           BlockDriverState *bs = acb->common.bs;
           acb->req.error = bdrv_co_flush(bs);
           acb->bh = qemu_bh_new(bdrv_co_em_bh, acb);
           qemu_bh_schedule(acb->bh);
+      }
       BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs,
               BlockDriverCompletionFunc *cb, void *opaque)
+      {
           trace_bdrv_aio_flush(bs, opaque);
           Coroutine *co;
           BlockDriverAIOCBCoroutine *acb;
           acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
           acb->done = NULL;
           co = qemu_coroutine_create(bdrv_aio_flush_co_entry);
           qemu_coroutine_enter(co, acb);
           return &acb->common;
+      }
       static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque)
+      {
           BlockDriverAIOCBCoroutine *acb = opaque;
           BlockDriverState *bs = acb->common.bs;
           acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors);
           acb->bh = qemu_bh_new(bdrv_co_em_bh, acb);
           qemu_bh_schedule(acb->bh);
+      }
       BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs,
               int64_t sector_num, int nb_sectors,
               BlockDriverCompletionFunc *cb, void *opaque)
+      {
           Coroutine *co;
           BlockDriverAIOCBCoroutine *acb;
           trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque);
           acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
           acb->req.sector = sector_num;
           acb->req.nb_sectors = nb_sectors;
           acb->done = NULL;
           co = qemu_coroutine_create(bdrv_aio_discard_co_entry);
           qemu_coroutine_enter(co, acb);
           return &acb->common;
+      }
       void bdrv_init(void)
+      {
           module_call_init(MODULE_INIT_BLOCK);
+      }
       void bdrv_init_with_whitelist(void)
+      {
           use_bdrv_whitelist = 1;
           bdrv_init();
+      }
       void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
                          BlockDriverCompletionFunc *cb, void *opaque)
+      {
           BlockDriverAIOCB *acb;
           acb = g_slice_alloc(aiocb_info->aiocb_size);
           acb->aiocb_info = aiocb_info;
           acb->bs = bs;
           acb->cb = cb;
           acb->opaque = opaque;
           return acb;
+      }
       void qemu_aio_release(void *p)
+      {
           BlockDriverAIOCB *acb = p;
           g_slice_free1(acb->aiocb_info->aiocb_size, acb);
+      }
       /**************************************************************/
       /* Coroutine block device emulation */
       typedef struct CoroutineIOCompletion {
           Coroutine *coroutine;
           int ret;
       } CoroutineIOCompletion;
       static void bdrv_co_io_em_complete(void *opaque, int ret)
+      {
           CoroutineIOCompletion *co = opaque;
           co->ret = ret;
           qemu_coroutine_enter(co->coroutine, NULL);
+      }
       static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num,
                                             int nb_sectors, QEMUIOVector *iov,
                                             bool is_write)
+      {
           CoroutineIOCompletion co = {
               .coroutine = qemu_coroutine_self(),
           };
           BlockDriverAIOCB *acb;
           if (is_write) {
               acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors,
                                              bdrv_co_io_em_complete, &co);
           } else {
               acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors,
                                             bdrv_co_io_em_complete, &co);
+          }
           trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb);
           if (!acb) {
               return -EIO;
+          }
           qemu_coroutine_yield();
           return co.ret;
+      }
       static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
                                                int64_t sector_num, int nb_sectors,
                                                QEMUIOVector *iov)
+      {
           return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false);
+      }
       static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
                                                int64_t sector_num, int nb_sectors,
                                                QEMUIOVector *iov)
+      {
           return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true);
+      }
       static void coroutine_fn bdrv_flush_co_entry(void *opaque)
+      {
           RwCo *rwco = opaque;
           rwco->ret = bdrv_co_flush(rwco->bs);
+      }
       int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
+      {
           int ret;
           if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
               return 0;
+          }
           /* Write back cached data to the OS even with cache=unsafe */
           BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS);
           if (bs->drv->bdrv_co_flush_to_os) {
               ret = bs->drv->bdrv_co_flush_to_os(bs);
               if (ret < 0) {
                   return ret;
+              }
+          }
           /* But don't actually force it to the disk with cache=unsafe */
           if (bs->open_flags & BDRV_O_NO_FLUSH) {
               goto flush_parent;
+          }
           BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK);
           if (bs->drv->bdrv_co_flush_to_disk) {
               ret = bs->drv->bdrv_co_flush_to_disk(bs);
           } else if (bs->drv->bdrv_aio_flush) {
               BlockDriverAIOCB *acb;
               CoroutineIOCompletion co = {
                   .coroutine = qemu_coroutine_self(),
               };
               acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co);
               if (acb == NULL) {
                   ret = -EIO;
               } else {
                   qemu_coroutine_yield();
                   ret = co.ret;
+              }
           } else {
               /*
                * Some block drivers always operate in either writethrough or unsafe
                * mode and don't support bdrv_flush therefore. Usually qemu doesn't
                * know how the server works (because the behaviour is hardcoded or
                * depends on server-side configuration), so we can't ensure that
                * everything is safe on disk. Returning an error doesn't work because
                * that would break guests even if the server operates in writethrough
                * mode.
+               *
                * Let's hope the user knows what he's doing.
                */
               ret = 0;
+          }
           if (ret < 0) {
               return ret;
+          }
           /* Now flush the underlying protocol.  It will also have BDRV_O_NO_FLUSH
            * in the case of cache=unsafe, so there are no useless flushes.
            */
       flush_parent:
           return bdrv_co_flush(bs->file);
+      }
       void bdrv_invalidate_cache(BlockDriverState *bs)
+      {
           if (bs->drv && bs->drv->bdrv_invalidate_cache) {
               bs->drv->bdrv_invalidate_cache(bs);
+          }
+      }
       void bdrv_invalidate_cache_all(void)
+      {
           BlockDriverState *bs;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               bdrv_invalidate_cache(bs);
+          }
+      }
       void bdrv_clear_incoming_migration_all(void)
+      {
           BlockDriverState *bs;
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING);
+          }
+      }
       int bdrv_flush(BlockDriverState *bs)
+      {
           Coroutine *co;
           RwCo rwco = {
               .bs = bs,
               .ret = NOT_DONE,
           };
           if (qemu_in_coroutine()) {
               /* Fast-path if already in coroutine context */
               bdrv_flush_co_entry(&rwco);
           } else {
               co = qemu_coroutine_create(bdrv_flush_co_entry);
               qemu_coroutine_enter(co, &rwco);
               while (rwco.ret == NOT_DONE) {
                   qemu_aio_wait();
+              }
+          }
           return rwco.ret;
+      }
       static void coroutine_fn bdrv_discard_co_entry(void *opaque)
+      {
           RwCo *rwco = opaque;
           rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors);
+      }
       /* if no limit is specified in the BlockLimits use a default
        * of 32768 512-byte sectors (16 MiB) per request.
        */
       #define MAX_DISCARD_DEFAULT 32768
       int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
                                        int nb_sectors)
+      {
           int max_discard;
           if (!bs->drv) {
               return -ENOMEDIUM;
           } else if (bdrv_check_request(bs, sector_num, nb_sectors)) {
               return -EIO;
           } else if (bs->read_only) {
               return -EROFS;
+          }
           bdrv_reset_dirty(bs, sector_num, nb_sectors);
           /* Do nothing if disabled.  */
           if (!(bs->open_flags & BDRV_O_UNMAP)) {
               return 0;
+          }
           if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) {
               return 0;
+          }
           max_discard = bs->bl.max_discard ?  bs->bl.max_discard : MAX_DISCARD_DEFAULT;
           while (nb_sectors > 0) {
               int ret;
               int num = nb_sectors;
               /* align request */
               if (bs->bl.discard_alignment &&
                   num >= bs->bl.discard_alignment &&
                   sector_num % bs->bl.discard_alignment) {
                   if (num > bs->bl.discard_alignment) {
                       num = bs->bl.discard_alignment;
+                  }
                   num -= sector_num % bs->bl.discard_alignment;
+              }
               /* limit request size */
               if (num > max_discard) {
                   num = max_discard;
+              }
               if (bs->drv->bdrv_co_discard) {
                   ret = bs->drv->bdrv_co_discard(bs, sector_num, num);
               } else {
                   BlockDriverAIOCB *acb;
                   CoroutineIOCompletion co = {
                       .coroutine = qemu_coroutine_self(),
                   };
                   acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors,
                                                   bdrv_co_io_em_complete, &co);
                   if (acb == NULL) {
                       return -EIO;
                   } else {
                       qemu_coroutine_yield();
                       ret = co.ret;
+                  }
+              }
               if (ret && ret != -ENOTSUP) {
                   return ret;
+              }
               sector_num += num;
               nb_sectors -= num;
+          }
           return 0;
+      }
       int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors)
+      {
           Coroutine *co;
           RwCo rwco = {
               .bs = bs,
               .sector_num = sector_num,
               .nb_sectors = nb_sectors,
               .ret = NOT_DONE,
           };
           if (qemu_in_coroutine()) {
               /* Fast-path if already in coroutine context */
               bdrv_discard_co_entry(&rwco);
           } else {
               co = qemu_coroutine_create(bdrv_discard_co_entry);
               qemu_coroutine_enter(co, &rwco);
               while (rwco.ret == NOT_DONE) {
                   qemu_aio_wait();
+              }
+          }
           return rwco.ret;
+      }
       /**************************************************************/
       /* removable device support */
       /**
        * Return TRUE if the media is present
        */
       int bdrv_is_inserted(BlockDriverState *bs)
+      {
           BlockDriver *drv = bs->drv;
           if (!drv)
               return 0;
           if (!drv->bdrv_is_inserted)
               return 1;
           return drv->bdrv_is_inserted(bs);
+      }
       /**
        * Return whether the media changed since the last call to this
        * function, or -ENOTSUP if we don't know.  Most drivers don't know.
        */
       int bdrv_media_changed(BlockDriverState *bs)
+      {
           BlockDriver *drv = bs->drv;
           if (drv && drv->bdrv_media_changed) {
               return drv->bdrv_media_changed(bs);
+          }
           return -ENOTSUP;
+      }
       /**
        * If eject_flag is TRUE, eject the media. Otherwise, close the tray
        */
       void bdrv_eject(BlockDriverState *bs, bool eject_flag)
+      {
           BlockDriver *drv = bs->drv;
           if (drv && drv->bdrv_eject) {
               drv->bdrv_eject(bs, eject_flag);
+          }
           if (bs->device_name[0] != '\0') {
               bdrv_emit_qmp_eject_event(bs, eject_flag);
+          }
+      }
       /**
        * Lock or unlock the media (if it is locked, the user won't be able
        * to eject it manually).
        */
       void bdrv_lock_medium(BlockDriverState *bs, bool locked)
+      {
           BlockDriver *drv = bs->drv;
           trace_bdrv_lock_medium(bs, locked);
           if (drv && drv->bdrv_lock_medium) {
               drv->bdrv_lock_medium(bs, locked);
+          }
+      }
       /* needed for generic scsi interface */
       int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
+      {
           BlockDriver *drv = bs->drv;
           if (drv && drv->bdrv_ioctl)
               return drv->bdrv_ioctl(bs, req, buf);
           return -ENOTSUP;
+      }
       BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
               unsigned long int req, void *buf,
               BlockDriverCompletionFunc *cb, void *opaque)
+      {
           BlockDriver *drv = bs->drv;
           if (drv && drv->bdrv_aio_ioctl)
               return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque);
           return NULL;
+      }
       void bdrv_set_guest_block_size(BlockDriverState *bs, int align)
+      {
           bs->guest_block_size = align;
+      }
       void *qemu_blockalign(BlockDriverState *bs, size_t size)
+      {
           return qemu_memalign(bdrv_opt_mem_align(bs), size);
+      }
       /*
        * Check if all memory in this vector is sector aligned.
        */
       bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
+      {
           int i;
           size_t alignment = bdrv_opt_mem_align(bs);
           for (i = 0; i < qiov->niov; i++) {
               if ((uintptr_t) qiov->iov[i].iov_base % alignment) {
                   return false;
+              }
               if (qiov->iov[i].iov_len % alignment) {
                   return false;
+              }
+          }
           return true;
+      }
       BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity)
+      {
           int64_t bitmap_size;
           BdrvDirtyBitmap *bitmap;
           assert((granularity & (granularity - 1)) == 0);
           granularity >>= BDRV_SECTOR_BITS;
           assert(granularity);
           bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS);
           bitmap = g_malloc0(sizeof(BdrvDirtyBitmap));
           bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1);
           QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
           return bitmap;
+      }
       void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
+      {
           BdrvDirtyBitmap *bm, *next;
           QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
               if (bm == bitmap) {
                   QLIST_REMOVE(bitmap, list);
                   hbitmap_free(bitmap->bitmap);
                   g_free(bitmap);
                   return;
+              }
+          }
+      }
       BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
+      {
           BdrvDirtyBitmap *bm;
           BlockDirtyInfoList *list = NULL;
           BlockDirtyInfoList **plist = &list;
           QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
               BlockDirtyInfo *info = g_malloc0(sizeof(BlockDirtyInfo));
               BlockDirtyInfoList *entry = g_malloc0(sizeof(BlockDirtyInfoList));
               info->count = bdrv_get_dirty_count(bs, bm);
               info->granularity =
                   ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap));
               entry->value = info;
               *plist = entry;
               plist = &entry->next;
+          }
           return list;
+      }
       int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector)
+      {
           if (bitmap) {
               return hbitmap_get(bitmap->bitmap, sector);
           } else {
               return 0;
+          }
+      }
       void bdrv_dirty_iter_init(BlockDriverState *bs,
                                 BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
+      {
           hbitmap_iter_init(hbi, bitmap->bitmap, 0);
+      }
       void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
                           int nr_sectors)
+      {
           BdrvDirtyBitmap *bitmap;
           QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
               hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+          }
+      }
       void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors)
+      {
           BdrvDirtyBitmap *bitmap;
           QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
               hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
+          }
+      }
       int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
+      {
           return hbitmap_count(bitmap->bitmap);
+      }
       /* Get a reference to bs */
       void bdrv_ref(BlockDriverState *bs)
+      {
           bs->refcnt++;
+      }
       /* Release a previously grabbed reference to bs.
        * If after releasing, reference count is zero, the BlockDriverState is
        * deleted. */
       void bdrv_unref(BlockDriverState *bs)
+      {
           assert(bs->refcnt > 0);
           if (--bs->refcnt == 0) {
               bdrv_delete(bs);
+          }
+      }
       void bdrv_set_in_use(BlockDriverState *bs, int in_use)
+      {
           assert(bs->in_use != in_use);
           bs->in_use = in_use;
+      }
       int bdrv_in_use(BlockDriverState *bs)
+      {
           return bs->in_use;
+      }
       void bdrv_iostatus_enable(BlockDriverState *bs)
+      {
           bs->iostatus_enabled = true;
           bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
+      }
       /* The I/O status is only enabled if the drive explicitly
        * enables it _and_ the VM is configured to stop on errors */
       bool bdrv_iostatus_is_enabled(const BlockDriverState *bs)
+      {
           return (bs->iostatus_enabled &&
                  (bs->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC ||
                   bs->on_write_error == BLOCKDEV_ON_ERROR_STOP   ||
                   bs->on_read_error == BLOCKDEV_ON_ERROR_STOP));
+      }
       void bdrv_iostatus_disable(BlockDriverState *bs)
+      {
           bs->iostatus_enabled = false;
+      }
       void bdrv_iostatus_reset(BlockDriverState *bs)
+      {
           if (bdrv_iostatus_is_enabled(bs)) {
               bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
               if (bs->job) {
                   block_job_iostatus_reset(bs->job);
+              }
+          }
+      }
       void bdrv_iostatus_set_err(BlockDriverState *bs, int error)
+      {
           assert(bdrv_iostatus_is_enabled(bs));
           if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
               bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
                                                BLOCK_DEVICE_IO_STATUS_FAILED;
+          }
+      }
       void
       bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes,
               enum BlockAcctType type)
+      {
           assert(type < BDRV_MAX_IOTYPE);
           cookie->bytes = bytes;
           cookie->start_time_ns = get_clock();
           cookie->type = type;
+      }
       void
       bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie)
+      {
           assert(cookie->type < BDRV_MAX_IOTYPE);
           bs->nr_bytes[cookie->type] += cookie->bytes;
           bs->nr_ops[cookie->type]++;
           bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns;
+      }
       void bdrv_img_create(const char *filename, const char *fmt,
                            const char *base_filename, const char *base_fmt,
                            char *options, uint64_t img_size, int flags,
                            Error **errp, bool quiet)
+      {
           QEMUOptionParameter *param = NULL, *create_options = NULL;
           QEMUOptionParameter *backing_fmt, *backing_file, *size;
           BlockDriver *drv, *proto_drv;
           BlockDriver *backing_drv = NULL;
           Error *local_err = NULL;
           int ret = 0;
           /* Find driver and parse its options */
           drv = bdrv_find_format(fmt);
           if (!drv) {
               error_setg(errp, "Unknown file format '%s'", fmt);
               return;
+          }
           proto_drv = bdrv_find_protocol(filename, true);
           if (!proto_drv) {
               error_setg(errp, "Unknown protocol '%s'", filename);
               return;
+          }
           create_options = append_option_parameters(create_options,
                                                     drv->create_options);
           create_options = append_option_parameters(create_options,
                                                     proto_drv->create_options);
           /* Create parameter list with default values */
           param = parse_option_parameters("", create_options, param);
           set_option_parameter_int(param, BLOCK_OPT_SIZE, img_size);
           /* Parse -o options */
           if (options) {
               param = parse_option_parameters(options, create_options, param);
               if (param == NULL) {
                   error_setg(errp, "Invalid options for file format '%s'.", fmt);
                   goto out;
+              }
+          }
           if (base_filename) {
               if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE,
                                        base_filename)) {
                   error_setg(errp, "Backing file not supported for file format '%s'",
                              fmt);
                   goto out;
+              }
+          }
           if (base_fmt) {
               if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) {
                   error_setg(errp, "Backing file format not supported for file "
                                    "format '%s'", fmt);
                   goto out;
+              }
+          }
           backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
           if (backing_file && backing_file->value.s) {
               if (!strcmp(filename, backing_file->value.s)) {
                   error_setg(errp, "Error: Trying to create an image with the "
                                    "same filename as the backing file");
                   goto out;
+              }
+          }
           backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT);
           if (backing_fmt && backing_fmt->value.s) {
               backing_drv = bdrv_find_format(backing_fmt->value.s);
               if (!backing_drv) {
                   error_setg(errp, "Unknown backing file format '%s'",
                              backing_fmt->value.s);
                   goto out;
+              }
+          }
           // The size for the image must always be specified, with one exception:
           // If we are using a backing file, we can obtain the size from there
           size = get_option_parameter(param, BLOCK_OPT_SIZE);
           if (size && size->value.n == -1) {
               if (backing_file && backing_file->value.s) {
                   BlockDriverState *bs;
                   uint64_t size;
                   char buf[32];
                   int back_flags;
                   /* backing files always opened read-only */
                   back_flags =
                       flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
                   bs = bdrv_new("");
                   ret = bdrv_open(bs, backing_file->value.s, NULL, back_flags,
                                   backing_drv, &local_err);
                   if (ret < 0) {
                       error_setg_errno(errp, -ret, "Could not open '%s': %s",
                                        backing_file->value.s,
                                        error_get_pretty(local_err));
                       error_free(local_err);
                       local_err = NULL;
                       bdrv_unref(bs);
                       goto out;
+                  }
                   bdrv_get_geometry(bs, &size);
                   size *= 512;
                   snprintf(buf, sizeof(buf), "%" PRId64, size);
                   set_option_parameter(param, BLOCK_OPT_SIZE, buf);
                   bdrv_unref(bs);
               } else {
                   error_setg(errp, "Image creation needs a size parameter");
                   goto out;
+              }
+          }
           if (!quiet) {
               printf("Formatting '%s', fmt=%s ", filename, fmt);
               print_option_parameters(param);
               puts("");
+          }
           ret = bdrv_create(drv, filename, param, &local_err);
           if (ret == -EFBIG) {
               /* This is generally a better message than whatever the driver would
                * deliver (especially because of the cluster_size_hint), since that
                * is most probably not much different from "image too large". */
               const char *cluster_size_hint = "";
               if (get_option_parameter(create_options, BLOCK_OPT_CLUSTER_SIZE)) {
                   cluster_size_hint = " (try using a larger cluster size)";
+              }
               error_setg(errp, "The image size is too large for file format '%s'"
                          "%s", fmt, cluster_size_hint);
               error_free(local_err);
               local_err = NULL;
+          }
       out:
           free_option_parameters(create_options);
           free_option_parameters(param);
           if (error_is_set(&local_err)) {
               error_propagate(errp, local_err);
+          }
+      }
       AioContext *bdrv_get_aio_context(BlockDriverState *bs)
+      {
           /* Currently BlockDriverState always uses the main loop AioContext */
           return qemu_get_aio_context();
+      }
       void bdrv_add_before_write_notifier(BlockDriverState *bs,
                                           NotifierWithReturn *notifier)
+      {
           notifier_with_return_list_add(&bs->before_write_notifiers, notifier);
+      }
       int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options)
+      {
           if (bs->drv->bdrv_amend_options == NULL) {
               return -ENOTSUP;
+          }
           return bs->drv->bdrv_amend_options(bs, options);
+      }
       /* Used to recurse on single child block filters.
        * Single child block filter will store their child in bs->file.
        */
       bool bdrv_generic_is_first_non_filter(BlockDriverState *bs,
                                             BlockDriverState *candidate)
+      {
           if (!bs->drv) {
               return false;
+          }
           if (!bs->drv->authorizations[BS_IS_A_FILTER]) {
               if (bs == candidate) {
                   return true;
               } else {
                   return false;
+              }
+          }
           if (!bs->drv->authorizations[BS_FILTER_PASS_DOWN]) {
               return false;
+          }
           if (!bs->file) {
               return false;
+          }
           return bdrv_recurse_is_first_non_filter(bs->file, candidate);
+      }
       bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
                                             BlockDriverState *candidate)
+      {
           if (bs->drv && bs->drv->bdrv_recurse_is_first_non_filter) {
               return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
+          }
           return bdrv_generic_is_first_non_filter(bs, candidate);
+      }
       /* This function checks if the candidate is the first non filter bs down it's
        * bs chain. Since we don't have pointers to parents it explore all bs chains
        * from the top. Some filters can choose not to pass down the recursion.
        */
       bool bdrv_is_first_non_filter(BlockDriverState *candidate)
+      {
           BlockDriverState *bs;
           /* walk down the bs forest recursively */
           QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
               bool perm;
               if (!bs->file) {
                   continue;
+              }
               perm = bdrv_recurse_is_first_non_filter(bs->file, candidate);
               /* candidate is the first non filter */
               if (perm) {
                   return true;
+              }
+          }
           return false;
+      }

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