Archipelago » qemu

block-nested-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o

/*

 * QEMU Enhanced Disk Format Cluster functions

 *

 * Copyright IBM, Corp. 2010

 *

 * Authors:

 *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU LGPL, version 2 or later.

 * See the COPYING.LIB file in the top-level directory.

 *

 */

#include "qed.h"

/**

 * Count the number of contiguous data clusters

 *

 * @s:              QED state

 * @table:          L2 table

 * @index:          First cluster index

 * @n:              Maximum number of clusters

 * @offset:         Set to first cluster offset

 *

 * This function scans tables for contiguous allocated or free clusters.

 */

static unsigned int qed_count_contiguous_clusters(BDRVQEDState *s,

                                                  QEDTable *table,

                                                  unsigned int index,

                                                  unsigned int n,

                                                  uint64_t *offset)

{

    unsigned int end = MIN(index + n, s->table_nelems);

    uint64_t last = table->offsets[index];

    unsigned int i;

    *offset = last;

    for (i = index + 1; i < end; i++) {

        if (last == 0) {

            /* Counting free clusters */

            if (table->offsets[i] != 0) {

                break;

            }

        } else {

            /* Counting allocated clusters */

            if (table->offsets[i] != last + s->header.cluster_size) {

                break;

            }

            last = table->offsets[i];

        }

    }

    return i - index;

}

typedef struct {

    BDRVQEDState *s;

    uint64_t pos;

    size_t len;

    QEDRequest *request;

    /* User callback */

    QEDFindClusterFunc *cb;

    void *opaque;

} QEDFindClusterCB;

static void qed_find_cluster_cb(void *opaque, int ret)

{

    QEDFindClusterCB *find_cluster_cb = opaque;

    BDRVQEDState *s = find_cluster_cb->s;

    QEDRequest *request = find_cluster_cb->request;

    uint64_t offset = 0;

    size_t len = 0;

    unsigned int index;

    unsigned int n;

    if (ret) {

        goto out;

    }

    index = qed_l2_index(s, find_cluster_cb->pos);

    n = qed_bytes_to_clusters(s,

                              qed_offset_into_cluster(s, find_cluster_cb->pos) +

                              find_cluster_cb->len);

    n = qed_count_contiguous_clusters(s, request->l2_table->table,

                                      index, n, &offset);

    ret = offset ? QED_CLUSTER_FOUND : QED_CLUSTER_L2;

    len = MIN(find_cluster_cb->len, n * s->header.cluster_size -

              qed_offset_into_cluster(s, find_cluster_cb->pos));

    if (offset && !qed_check_cluster_offset(s, offset)) {

        ret = -EINVAL;

    }

out:

    find_cluster_cb->cb(find_cluster_cb->opaque, ret, offset, len);

    qemu_free(find_cluster_cb);

}

/**

 * Find the offset of a data cluster

 *

 * @s:          QED state

 * @request:    L2 cache entry

 * @pos:        Byte position in device

 * @len:        Number of bytes

 * @cb:         Completion function

 * @opaque:     User data for completion function

 *

 * This function translates a position in the block device to an offset in the

 * image file.  It invokes the cb completion callback to report back the

 * translated offset or unallocated range in the image file.

 *

 * If the L2 table exists, request->l2_table points to the L2 table cache entry

 * and the caller must free the reference when they are finished.  The cache

 * entry is exposed in this way to avoid callers having to read the L2 table

 * again later during request processing.  If request->l2_table is non-NULL it

 * will be unreferenced before taking on the new cache entry.

 */

void qed_find_cluster(BDRVQEDState *s, QEDRequest *request, uint64_t pos,

                      size_t len, QEDFindClusterFunc *cb, void *opaque)

{

    QEDFindClusterCB *find_cluster_cb;

    uint64_t l2_offset;

    /* Limit length to L2 boundary.  Requests are broken up at the L2 boundary

     * so that a request acts on one L2 table at a time.

     */

    len = MIN(len, (((pos >> s->l1_shift) + 1) << s->l1_shift) - pos);

    l2_offset = s->l1_table->offsets[qed_l1_index(s, pos)];

    if (!l2_offset) {

        cb(opaque, QED_CLUSTER_L1, 0, len);

        return;

    }

    if (!qed_check_table_offset(s, l2_offset)) {

        cb(opaque, -EINVAL, 0, 0);

        return;

    }

    find_cluster_cb = qemu_malloc(sizeof(*find_cluster_cb));

    find_cluster_cb->s = s;

    find_cluster_cb->pos = pos;

    find_cluster_cb->len = len;

    find_cluster_cb->cb = cb;

    find_cluster_cb->opaque = opaque;

    find_cluster_cb->request = request;

    qed_read_l2_table(s, request, l2_offset,

                      qed_find_cluster_cb, find_cluster_cb);

}

/*

 * QEMU Enhanced Disk Format

 *

 * Copyright IBM, Corp. 2010

 *

 * Authors:

 *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>

 *

 * This work is licensed under the terms of the GNU LGPL, version 2 or later.

 * See the COPYING.LIB file in the top-level directory.

 *

 */

#include "qed.h"

void *gencb_alloc(size_t len, BlockDriverCompletionFunc *cb, void *opaque)

{

    GenericCB *gencb = qemu_malloc(len);

    gencb->cb = cb;

    gencb->opaque = opaque;

    return gencb;

}

void gencb_complete(void *opaque, int ret)

{

    GenericCB *gencb = opaque;

    BlockDriverCompletionFunc *cb = gencb->cb;

    void *user_opaque = gencb->opaque;

    qemu_free(gencb);

    cb(user_opaque, ret);

}

/*

 * QEMU Enhanced Disk Format L2 Cache

 *

 * Copyright IBM, Corp. 2010

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU LGPL, version 2 or later.

 * See the COPYING.LIB file in the top-level directory.

 *

 */

/*

 * L2 table cache usage is as follows:

 *

 * An open image has one L2 table cache that is used to avoid accessing the

 * image file for recently referenced L2 tables.

 *

 * Cluster offset lookup translates the logical offset within the block device

 * to a cluster offset within the image file.  This is done by indexing into

 * the L1 and L2 tables which store cluster offsets.  It is here where the L2

 * table cache serves up recently referenced L2 tables.

 *

 * If there is a cache miss, that L2 table is read from the image file and

 * committed to the cache.  Subsequent accesses to that L2 table will be served

 * from the cache until the table is evicted from the cache.

 *

 * L2 tables are also committed to the cache when new L2 tables are allocated

 * in the image file.  Since the L2 table cache is write-through, the new L2

 * table is first written out to the image file and then committed to the

 * cache.

 *

 * Multiple I/O requests may be using an L2 table cache entry at any given

 * time.  That means an entry may be in use across several requests and

 * reference counting is needed to free the entry at the correct time.  In

 * particular, an entry evicted from the cache will only be freed once all

 * references are dropped.

 *

 * An in-flight I/O request will hold a reference to a L2 table cache entry for

 * the period during which it needs to access the L2 table.  This includes

 * cluster offset lookup, L2 table allocation, and L2 table update when a new

 * data cluster has been allocated.

 *

 * An interesting case occurs when two requests need to access an L2 table that

 * is not in the cache.  Since the operation to read the table from the image

 * file takes some time to complete, both requests may see a cache miss and

 * start reading the L2 table from the image file.  The first to finish will

 * commit its L2 table into the cache.  When the second tries to commit its

 * table will be deleted in favor of the existing cache entry.

 */

#include "trace.h"

#include "qed.h"

/* Each L2 holds 2GB so this let's us fully cache a 100GB disk */

#define MAX_L2_CACHE_SIZE 50

/**

 * Initialize the L2 cache

 */

void qed_init_l2_cache(L2TableCache *l2_cache)

{

    QTAILQ_INIT(&l2_cache->entries);

    l2_cache->n_entries = 0;

}

/**

 * Free the L2 cache

 */

void qed_free_l2_cache(L2TableCache *l2_cache)

{

    CachedL2Table *entry, *next_entry;

    QTAILQ_FOREACH_SAFE(entry, &l2_cache->entries, node, next_entry) {

        qemu_vfree(entry->table);

        qemu_free(entry);

    }

}

/**

 * Allocate an uninitialized entry from the cache

 *

 * The returned entry has a reference count of 1 and is owned by the caller.

 * The caller must allocate the actual table field for this entry and it must

 * be freeable using qemu_vfree().

 */

CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache)

{

    CachedL2Table *entry;

    entry = qemu_mallocz(sizeof(*entry));

    entry->ref++;

    trace_qed_alloc_l2_cache_entry(l2_cache, entry);

    return entry;

}

/**

 * Decrease an entry's reference count and free if necessary when the reference

 * count drops to zero.

 */

void qed_unref_l2_cache_entry(CachedL2Table *entry)

{

    if (!entry) {

        return;

    }

    entry->ref--;

    trace_qed_unref_l2_cache_entry(entry, entry->ref);

    if (entry->ref == 0) {

        qemu_vfree(entry->table);

        qemu_free(entry);

    }

}

/**

 * Find an entry in the L2 cache.  This may return NULL and it's up to the

 * caller to satisfy the cache miss.

 *

 * For a cached entry, this function increases the reference count and returns

 * the entry.

 */

CachedL2Table *qed_find_l2_cache_entry(L2TableCache *l2_cache, uint64_t offset)

{

    CachedL2Table *entry;

    QTAILQ_FOREACH(entry, &l2_cache->entries, node) {

        if (entry->offset == offset) {

            trace_qed_find_l2_cache_entry(l2_cache, entry, offset, entry->ref);

            entry->ref++;

            return entry;

        }

    }

    return NULL;

}

/**

 * Commit an L2 cache entry into the cache.  This is meant to be used as part of

 * the process to satisfy a cache miss.  A caller would allocate an entry which

 * is not actually in the L2 cache and then once the entry was valid and

 * present on disk, the entry can be committed into the cache.

 *

 * Since the cache is write-through, it's important that this function is not

 * called until the entry is present on disk and the L1 has been updated to

 * point to the entry.

 *

 * N.B. This function steals a reference to the l2_table from the caller so the

 * caller must obtain a new reference by issuing a call to

 * qed_find_l2_cache_entry().

 */

void qed_commit_l2_cache_entry(L2TableCache *l2_cache, CachedL2Table *l2_table)

{

    CachedL2Table *entry;

    entry = qed_find_l2_cache_entry(l2_cache, l2_table->offset);

    if (entry) {

        qed_unref_l2_cache_entry(entry);

        qed_unref_l2_cache_entry(l2_table);

        return;

    }

    if (l2_cache->n_entries >= MAX_L2_CACHE_SIZE) {

        entry = QTAILQ_FIRST(&l2_cache->entries);

        QTAILQ_REMOVE(&l2_cache->entries, entry, node);

        l2_cache->n_entries--;

        qed_unref_l2_cache_entry(entry);

    }

    l2_cache->n_entries++;

    QTAILQ_INSERT_TAIL(&l2_cache->entries, l2_table, node);

}

/*

 * QEMU Enhanced Disk Format Table I/O

 *

 * Copyright IBM, Corp. 2010

 *

 * Authors:

 *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU LGPL, version 2 or later.

 * See the COPYING.LIB file in the top-level directory.

 *

 */

#include "trace.h"

#include "qemu_socket.h" /* for EINPROGRESS on Windows */

#include "qed.h"

typedef struct {

    GenericCB gencb;

    BDRVQEDState *s;

    QEDTable *table;

    struct iovec iov;

    QEMUIOVector qiov;

} QEDReadTableCB;

static void qed_read_table_cb(void *opaque, int ret)

{

    QEDReadTableCB *read_table_cb = opaque;

    QEDTable *table = read_table_cb->table;

    int noffsets = read_table_cb->iov.iov_len / sizeof(uint64_t);

    int i;

    /* Handle I/O error */

    if (ret) {

        goto out;

    }

    /* Byteswap offsets */

    for (i = 0; i < noffsets; i++) {

        table->offsets[i] = le64_to_cpu(table->offsets[i]);

    }

out:

    /* Completion */

    trace_qed_read_table_cb(read_table_cb->s, read_table_cb->table, ret);

    gencb_complete(&read_table_cb->gencb, ret);

}

static void qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,

                           BlockDriverCompletionFunc *cb, void *opaque)

{

    QEDReadTableCB *read_table_cb = gencb_alloc(sizeof(*read_table_cb),

                                                cb, opaque);

    QEMUIOVector *qiov = &read_table_cb->qiov;

    BlockDriverAIOCB *aiocb;

    trace_qed_read_table(s, offset, table);

    read_table_cb->s = s;

    read_table_cb->table = table;

    read_table_cb->iov.iov_base = table->offsets,

    read_table_cb->iov.iov_len = s->header.cluster_size * s->header.table_size,

    qemu_iovec_init_external(qiov, &read_table_cb->iov, 1);

    aiocb = bdrv_aio_readv(s->bs->file, offset / BDRV_SECTOR_SIZE, qiov,

                           read_table_cb->iov.iov_len / BDRV_SECTOR_SIZE,

                           qed_read_table_cb, read_table_cb);

    if (!aiocb) {

        qed_read_table_cb(read_table_cb, -EIO);

    }

}

typedef struct {

    GenericCB gencb;

    BDRVQEDState *s;

    QEDTable *orig_table;

    QEDTable *table;

    bool flush;             /* flush after write? */

    struct iovec iov;

    QEMUIOVector qiov;

} QEDWriteTableCB;

static void qed_write_table_cb(void *opaque, int ret)

{

    QEDWriteTableCB *write_table_cb = opaque;

    trace_qed_write_table_cb(write_table_cb->s,

                             write_table_cb->orig_table,

                             write_table_cb->flush,

                             ret);

    if (ret) {

        goto out;

    }

    if (write_table_cb->flush) {

        /* We still need to flush first */

        write_table_cb->flush = false;

        bdrv_aio_flush(write_table_cb->s->bs, qed_write_table_cb,

                       write_table_cb);

        return;

    }

out:

    qemu_vfree(write_table_cb->table);

    gencb_complete(&write_table_cb->gencb, ret);

    return;

}

/**

 * Write out an updated part or all of a table

 *

 * @s:          QED state

 * @offset:     Offset of table in image file, in bytes

 * @table:      Table

 * @index:      Index of first element

 * @n:          Number of elements

 * @flush:      Whether or not to sync to disk

 * @cb:         Completion function

 * @opaque:     Argument for completion function

 */

static void qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,

                            unsigned int index, unsigned int n, bool flush,

                            BlockDriverCompletionFunc *cb, void *opaque)

{

    QEDWriteTableCB *write_table_cb;

    BlockDriverAIOCB *aiocb;

    unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;

    unsigned int start, end, i;

    size_t len_bytes;

    trace_qed_write_table(s, offset, table, index, n);

    /* Calculate indices of the first and one after last elements */

    start = index & ~sector_mask;

    end = (index + n + sector_mask) & ~sector_mask;

    len_bytes = (end - start) * sizeof(uint64_t);

    write_table_cb = gencb_alloc(sizeof(*write_table_cb), cb, opaque);

    write_table_cb->s = s;

    write_table_cb->orig_table = table;

    write_table_cb->flush = flush;

    write_table_cb->table = qemu_blockalign(s->bs, len_bytes);

    write_table_cb->iov.iov_base = write_table_cb->table->offsets;

    write_table_cb->iov.iov_len = len_bytes;

    qemu_iovec_init_external(&write_table_cb->qiov, &write_table_cb->iov, 1);

    /* Byteswap table */

    for (i = start; i < end; i++) {

        uint64_t le_offset = cpu_to_le64(table->offsets[i]);

        write_table_cb->table->offsets[i - start] = le_offset;

    }

    /* Adjust for offset into table */

    offset += start * sizeof(uint64_t);

    aiocb = bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE,

                            &write_table_cb->qiov,

                            write_table_cb->iov.iov_len / BDRV_SECTOR_SIZE,

                            qed_write_table_cb, write_table_cb);

    if (!aiocb) {

        qed_write_table_cb(write_table_cb, -EIO);

    }

}

/**

 * Propagate return value from async callback

 */

static void qed_sync_cb(void *opaque, int ret)

{

    *(int *)opaque = ret;

}

int qed_read_l1_table_sync(BDRVQEDState *s)

{

    int ret = -EINPROGRESS;

    async_context_push();

    qed_read_table(s, s->header.l1_table_offset,

                   s->l1_table, qed_sync_cb, &ret);

    while (ret == -EINPROGRESS) {

        qemu_aio_wait();

    }

    async_context_pop();

    return ret;

}

void qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n,

                        BlockDriverCompletionFunc *cb, void *opaque)

{

    BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);

    qed_write_table(s, s->header.l1_table_offset,

                    s->l1_table, index, n, false, cb, opaque);

}

int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,

                            unsigned int n)

{

    int ret = -EINPROGRESS;

    async_context_push();

    qed_write_l1_table(s, index, n, qed_sync_cb, &ret);

    while (ret == -EINPROGRESS) {

        qemu_aio_wait();

    }

    async_context_pop();

    return ret;

}

typedef struct {

    GenericCB gencb;

    BDRVQEDState *s;

    uint64_t l2_offset;

    QEDRequest *request;

} QEDReadL2TableCB;

static void qed_read_l2_table_cb(void *opaque, int ret)

{

    QEDReadL2TableCB *read_l2_table_cb = opaque;

    QEDRequest *request = read_l2_table_cb->request;

    BDRVQEDState *s = read_l2_table_cb->s;

    CachedL2Table *l2_table = request->l2_table;

    if (ret) {

        /* can't trust loaded L2 table anymore */

        qed_unref_l2_cache_entry(l2_table);

        request->l2_table = NULL;

    } else {

        l2_table->offset = read_l2_table_cb->l2_offset;

        qed_commit_l2_cache_entry(&s->l2_cache, l2_table);

        /* This is guaranteed to succeed because we just committed the entry

         * to the cache.

         */

        request->l2_table = qed_find_l2_cache_entry(&s->l2_cache,

                                                    l2_table->offset);

        assert(request->l2_table != NULL);

    }

    gencb_complete(&read_l2_table_cb->gencb, ret);

}

void qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset,

                       BlockDriverCompletionFunc *cb, void *opaque)

{

    QEDReadL2TableCB *read_l2_table_cb;

    qed_unref_l2_cache_entry(request->l2_table);

    /* Check for cached L2 entry */

    request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);

    if (request->l2_table) {

        cb(opaque, 0);

        return;

    }

    request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);

    request->l2_table->table = qed_alloc_table(s);

    read_l2_table_cb = gencb_alloc(sizeof(*read_l2_table_cb), cb, opaque);

    read_l2_table_cb->s = s;

    read_l2_table_cb->l2_offset = offset;

    read_l2_table_cb->request = request;

    BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);

    qed_read_table(s, offset, request->l2_table->table,

                   qed_read_l2_table_cb, read_l2_table_cb);

}

int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset)

{

    int ret = -EINPROGRESS;

    async_context_push();

    qed_read_l2_table(s, request, offset, qed_sync_cb, &ret);

    while (ret == -EINPROGRESS) {

        qemu_aio_wait();

    }

    async_context_pop();

    return ret;

}

void qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,

                        unsigned int index, unsigned int n, bool flush,

                        BlockDriverCompletionFunc *cb, void *opaque)

{

    BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);

    qed_write_table(s, request->l2_table->offset,

                    request->l2_table->table, index, n, flush, cb, opaque);

}

int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,

                            unsigned int index, unsigned int n, bool flush)

{

    int ret = -EINPROGRESS;

    async_context_push();

    qed_write_l2_table(s, request, index, n, flush, qed_sync_cb, &ret);

    while (ret == -EINPROGRESS) {

        qemu_aio_wait();

    }

    async_context_pop();

    return ret;

}

QEDTable *qed_alloc_table(BDRVQEDState *s)

{

    /* Honor O_DIRECT memory alignment requirements */

    return qemu_blockalign(s->bs,

                           s->header.cluster_size * s->header.table_size);

}

    s->l1_table = qed_alloc_table(s);

    qed_init_l2_cache(&s->l2_cache);

    ret = qed_read_l1_table_sync(s);

    if (ret) {

        qed_free_l2_cache(&s->l2_cache);

        qemu_vfree(s->l1_table);

    }

    BDRVQEDState *s = bs->opaque;

    qed_free_l2_cache(&s->l2_cache);

    qemu_vfree(s->l1_table);

typedef struct {

    int is_allocated;

    int *pnum;

} QEDIsAllocatedCB;

static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len)

{

    QEDIsAllocatedCB *cb = opaque;

    *cb->pnum = len / BDRV_SECTOR_SIZE;

    cb->is_allocated = ret == QED_CLUSTER_FOUND;

}

    BDRVQEDState *s = bs->opaque;

    uint64_t pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;

    size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE;

    QEDIsAllocatedCB cb = {

        .is_allocated = -1,

        .pnum = pnum,

    };

    QEDRequest request = { .l2_table = NULL };

    async_context_push();

    qed_find_cluster(s, &request, pos, len, qed_is_allocated_cb, &cb);

    while (cb.is_allocated == -1) {

        qemu_aio_wait();

    }

    async_context_pop();

    qed_unref_l2_cache_entry(request.l2_table);

    return cb.is_allocated;

    uint64_t offsets[0];            /* in bytes */

} QEDTable;

/* The L2 cache is a simple write-through cache for L2 structures */

typedef struct CachedL2Table {

    QEDTable *table;

    uint64_t offset;    /* offset=0 indicates an invalidate entry */

    QTAILQ_ENTRY(CachedL2Table) node;

    int ref;

} CachedL2Table;

typedef struct {

    QTAILQ_HEAD(, CachedL2Table) entries;

    unsigned int n_entries;

} L2TableCache;

typedef struct QEDRequest {

    CachedL2Table *l2_table;

} QEDRequest;

typedef struct {

    QEDTable *l1_table;

    L2TableCache l2_cache;          /* l2 table cache */

enum {

    QED_CLUSTER_FOUND,         /* cluster found */

    QED_CLUSTER_L2,            /* cluster missing in L2 */

    QED_CLUSTER_L1,            /* cluster missing in L1 */

};

/**

 * qed_find_cluster() completion callback

 *

 * @opaque:     User data for completion callback

 * @ret:        QED_CLUSTER_FOUND   Success

 *              QED_CLUSTER_L2      Data cluster unallocated in L2

 *              QED_CLUSTER_L1      L2 unallocated in L1

 *              -errno              POSIX error occurred

 * @offset:     Data cluster offset

 * @len:        Contiguous bytes starting from cluster offset

 *

 * This function is invoked when qed_find_cluster() completes.

 *

 * On success ret is QED_CLUSTER_FOUND and offset/len are a contiguous range

 * in the image file.

 *

 * On failure ret is QED_CLUSTER_L2 or QED_CLUSTER_L1 for missing L2 or L1

 * table offset, respectively.  len is number of contiguous unallocated bytes.

 */

typedef void QEDFindClusterFunc(void *opaque, int ret, uint64_t offset, size_t len);

/**

 * Generic callback for chaining async callbacks

 */

typedef struct {

    BlockDriverCompletionFunc *cb;

    void *opaque;

} GenericCB;

void *gencb_alloc(size_t len, BlockDriverCompletionFunc *cb, void *opaque);

void gencb_complete(void *opaque, int ret);

/**

 * L2 cache functions

 */

void qed_init_l2_cache(L2TableCache *l2_cache);

void qed_free_l2_cache(L2TableCache *l2_cache);

CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache);

void qed_unref_l2_cache_entry(CachedL2Table *entry);

CachedL2Table *qed_find_l2_cache_entry(L2TableCache *l2_cache, uint64_t offset);

void qed_commit_l2_cache_entry(L2TableCache *l2_cache, CachedL2Table *l2_table);

/**

 * Table I/O functions

 */

int qed_read_l1_table_sync(BDRVQEDState *s);

void qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n,

                        BlockDriverCompletionFunc *cb, void *opaque);

int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,

                            unsigned int n);

int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request,

                           uint64_t offset);

void qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset,

                       BlockDriverCompletionFunc *cb, void *opaque);

void qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,

                        unsigned int index, unsigned int n, bool flush,

                        BlockDriverCompletionFunc *cb, void *opaque);

int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,

                            unsigned int index, unsigned int n, bool flush);

/**

 * Cluster functions

 */

void qed_find_cluster(BDRVQEDState *s, QEDRequest *request, uint64_t pos,

                      size_t len, QEDFindClusterFunc *cb, void *opaque);

/**

 * Consistency check

 */

int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix);

QEDTable *qed_alloc_table(BDRVQEDState *s);

static inline uint64_t qed_offset_into_cluster(BDRVQEDState *s, uint64_t offset)

{

    return offset & (s->header.cluster_size - 1);

}

static inline unsigned int qed_bytes_to_clusters(BDRVQEDState *s, size_t bytes)

{

    return qed_start_of_cluster(s, bytes + (s->header.cluster_size - 1)) /

           (s->header.cluster_size - 1);

}

static inline unsigned int qed_l1_index(BDRVQEDState *s, uint64_t pos)

{

    return pos >> s->l1_shift;

}

static inline unsigned int qed_l2_index(BDRVQEDState *s, uint64_t pos)

{

    return (pos >> s->l2_shift) & s->l2_mask;

}

# block/qed-l2-cache.c

disable qed_alloc_l2_cache_entry(void *l2_cache, void *entry) "l2_cache %p entry %p"

disable qed_unref_l2_cache_entry(void *entry, int ref) "entry %p ref %d"

disable qed_find_l2_cache_entry(void *l2_cache, void *entry, uint64_t offset, int ref) "l2_cache %p entry %p offset %"PRIu64" ref %d"

# block/qed-table.c

disable qed_read_table(void *s, uint64_t offset, void *table) "s %p offset %"PRIu64" table %p"

disable qed_read_table_cb(void *s, void *table, int ret) "s %p table %p ret %d"

disable qed_write_table(void *s, uint64_t offset, void *table, unsigned int index, unsigned int n) "s %p offset %"PRIu64" table %p index %u n %u"

disable qed_write_table_cb(void *s, void *table, int flush, int ret) "s %p table %p flush %d ret %d"