aspeed: introduce a configurable number of CPU per machine

[qemu.git] / block / commit.c

diff --git a/block/commit.c b/block/commit.c
index 76a0d98c6f5c0678e0135e9bd83ffc7eb0063aca..212c6f639edcc251b2a6dd7c1a81ad8b0b4a5a33 100644 (file)
--- a/block/commit.c
+++ b/block/commit.c
@@ -31,42 +31,32 @@ enum {
     COMMIT_BUFFER_SIZE = 512 * 1024, /* in bytes */
 };
 
     COMMIT_BUFFER_SIZE = 512 * 1024, /* in bytes */
 };
 

-#define SLICE_TIME 100000000ULL /* ns */
-

 typedef struct CommitBlockJob {
     BlockJob common;
 typedef struct CommitBlockJob {
     BlockJob common;

-    RateLimit limit;
-    BlockDriverState *active;

     BlockDriverState *commit_top_bs;
     BlockBackend *top;
     BlockBackend *base;
     BlockDriverState *commit_top_bs;
     BlockBackend *top;
     BlockBackend *base;

+    BlockDriverState *base_bs;

     BlockdevOnError on_error;
     BlockdevOnError on_error;

-    int base_flags;
-    int orig_overlay_flags;
+    bool base_read_only;
+    bool chain_frozen;

     char *backing_file_str;
 } CommitBlockJob;
 
 static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
     char *backing_file_str;
 } CommitBlockJob;
 
 static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,

-                                        int64_t sector_num, int nb_sectors,
+                                        int64_t offset, uint64_t bytes,

                                         void *buf)
 {
     int ret = 0;
                                         void *buf)
 {
     int ret = 0;

-    QEMUIOVector qiov;
-    struct iovec iov = {
-        .iov_base = buf,
-        .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
-    };

 
 

-    qemu_iovec_init_external(&qiov, &iov, 1);
+    assert(bytes < SIZE_MAX);

 
 

-    ret = blk_co_preadv(bs, sector_num * BDRV_SECTOR_SIZE,
-                        qiov.size, &qiov, 0);
+    ret = blk_co_pread(bs, offset, bytes, buf, 0);

     if (ret < 0) {
         return ret;
     }
 
     if (ret < 0) {
         return ret;
     }
 

-    ret = blk_co_pwritev(base, sector_num * BDRV_SECTOR_SIZE,
-                         qiov.size, &qiov, 0);
+    ret = blk_co_pwrite(base, offset, bytes, buf, 0);

     if (ret < 0) {
         return ret;
     }
     if (ret < 0) {
         return ret;
     }


@@ -74,112 +64,123 @@ static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
     return 0;
 }
 
     return 0;
 }
 

-typedef struct {
-    int ret;
-} CommitCompleteData;
-
-static void commit_complete(BlockJob *job, void *opaque)
+static int commit_prepare(Job *job)

 {
 {

-    CommitBlockJob *s = container_of(job, CommitBlockJob, common);
-    CommitCompleteData *data = opaque;
-    BlockDriverState *active = s->active;
-    BlockDriverState *top = blk_bs(s->top);
-    BlockDriverState *base = blk_bs(s->base);
-    BlockDriverState *overlay_bs = bdrv_find_overlay(active, s->commit_top_bs);
-    int ret = data->ret;
-    bool remove_commit_top_bs = false;
+    CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
+
+    bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs);
+    s->chain_frozen = false;

 
     /* Remove base node parent that still uses BLK_PERM_WRITE/RESIZE before
      * the normal backing chain can be restored. */
     blk_unref(s->base);
 
     /* Remove base node parent that still uses BLK_PERM_WRITE/RESIZE before
      * the normal backing chain can be restored. */
     blk_unref(s->base);

+    s->base = NULL;
+
+    /* FIXME: bdrv_drop_intermediate treats total failures and partial failures
+     * identically. Further work is needed to disambiguate these cases. */
+    return bdrv_drop_intermediate(s->commit_top_bs, s->base_bs,
+                                  s->backing_file_str);
+}
+
+static void commit_abort(Job *job)
+{
+    CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
+    BlockDriverState *top_bs = blk_bs(s->top);

 
 

-    if (!block_job_is_cancelled(&s->common) && ret == 0) {
-        /* success */
-        ret = bdrv_drop_intermediate(active, s->commit_top_bs, base,
-                                     s->backing_file_str);
-    } else if (overlay_bs) {
-        /* XXX Can (or should) we somehow keep 'consistent read' blocked even
-         * after the failed/cancelled commit job is gone? If we already wrote
-         * something to base, the intermediate images aren't valid any more. */
-        remove_commit_top_bs = true;
+    if (s->chain_frozen) {
+        bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs);

     }
 
     }
 

+    /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */
+    bdrv_ref(top_bs);
+    bdrv_ref(s->commit_top_bs);
+
+    if (s->base) {
+        blk_unref(s->base);
+    }
+
+    /* free the blockers on the intermediate nodes so that bdrv_replace_nodes
+     * can succeed */
+    block_job_remove_all_bdrv(&s->common);
+
+    /* If bdrv_drop_intermediate() failed (or was not invoked), remove the
+     * commit filter driver from the backing chain now. Do this as the final
+     * step so that the 'consistent read' permission can be granted.
+     *
+     * XXX Can (or should) we somehow keep 'consistent read' blocked even
+     * after the failed/cancelled commit job is gone? If we already wrote
+     * something to base, the intermediate images aren't valid any more. */
+    bdrv_replace_node(s->commit_top_bs, backing_bs(s->commit_top_bs),
+                      &error_abort);
+
+    bdrv_unref(s->commit_top_bs);
+    bdrv_unref(top_bs);
+}
+
+static void commit_clean(Job *job)
+{
+    CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
+

     /* restore base open flags here if appropriate (e.g., change the base back
      * to r/o). These reopens do not need to be atomic, since we won't abort
      * even on failure here */
     /* restore base open flags here if appropriate (e.g., change the base back
      * to r/o). These reopens do not need to be atomic, since we won't abort
      * even on failure here */

-    if (s->base_flags != bdrv_get_flags(base)) {
-        bdrv_reopen(base, s->base_flags, NULL);
-    }
-    if (overlay_bs && s->orig_overlay_flags != bdrv_get_flags(overlay_bs)) {
-        bdrv_reopen(overlay_bs, s->orig_overlay_flags, NULL);
+    if (s->base_read_only) {
+        bdrv_reopen_set_read_only(s->base_bs, true, NULL);

     }
     }

+

     g_free(s->backing_file_str);
     blk_unref(s->top);
     g_free(s->backing_file_str);
     blk_unref(s->top);

-    block_job_completed(&s->common, ret);
-    g_free(data);
-
-    /* If bdrv_drop_intermediate() didn't already do that, remove the commit
-     * filter driver from the backing chain. Do this as the final step so that
-     * the 'consistent read' permission can be granted.  */
-    if (remove_commit_top_bs) {
-        bdrv_set_backing_hd(overlay_bs, top, &error_abort);
-    }

 }
 
 }
 

-static void coroutine_fn commit_run(void *opaque)
+static int coroutine_fn commit_run(Job *job, Error **errp)

 {
 {

-    CommitBlockJob *s = opaque;
-    CommitCompleteData *data;
-    int64_t sector_num, end;
+    CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
+    int64_t offset;

     uint64_t delay_ns = 0;
     int ret = 0;
     uint64_t delay_ns = 0;
     int ret = 0;

-    int n = 0;
+    int64_t n = 0; /* bytes */

     void *buf = NULL;
     int bytes_written = 0;
     void *buf = NULL;
     int bytes_written = 0;

-    int64_t base_len;
-
-    ret = s->common.len = blk_getlength(s->top);
+    int64_t len, base_len;

 
 

-
-    if (s->common.len < 0) {
+    ret = len = blk_getlength(s->top);
+    if (len < 0) {

         goto out;
     }
         goto out;
     }

+    job_progress_set_remaining(&s->common.job, len);

 
     ret = base_len = blk_getlength(s->base);
     if (base_len < 0) {
         goto out;
     }
 
 
     ret = base_len = blk_getlength(s->base);
     if (base_len < 0) {
         goto out;
     }
 

-    if (base_len < s->common.len) {
-        ret = blk_truncate(s->base, s->common.len, NULL);
+    if (base_len < len) {
+        ret = blk_truncate(s->base, len, PREALLOC_MODE_OFF, NULL);

         if (ret) {
             goto out;
         }
     }
 
         if (ret) {
             goto out;
         }
     }
 

-    end = s->common.len >> BDRV_SECTOR_BITS;

     buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
 
     buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
 

-    for (sector_num = 0; sector_num < end; sector_num += n) {
+    for (offset = 0; offset < len; offset += n) {

         bool copy;
 
         /* Note that even when no rate limit is applied we need to yield
          * with no pending I/O here so that bdrv_drain_all() returns.
          */
         bool copy;
 
         /* Note that even when no rate limit is applied we need to yield
          * with no pending I/O here so that bdrv_drain_all() returns.
          */

-        block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
-        if (block_job_is_cancelled(&s->common)) {
+        job_sleep_ns(&s->common.job, delay_ns);
+        if (job_is_cancelled(&s->common.job)) {

             break;
         }
         /* Copy if allocated above the base */
         ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
             break;
         }
         /* Copy if allocated above the base */
         ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),

-                                      sector_num,
-                                      COMMIT_BUFFER_SIZE / BDRV_SECTOR_SIZE,
-                                      &n);
+                                      offset, COMMIT_BUFFER_SIZE, &n);

         copy = (ret == 1);
         copy = (ret == 1);

-        trace_commit_one_iteration(s, sector_num, n, ret);
+        trace_commit_one_iteration(s, offset, n, ret);

         if (copy) {
         if (copy) {

-            ret = commit_populate(s->top, s->base, sector_num, n, buf);
-            bytes_written += n * BDRV_SECTOR_SIZE;
+            ret = commit_populate(s->top, s->base, offset, n, buf);
+            bytes_written += n;

         }
         if (ret < 0) {
             BlockErrorAction action =
         }
         if (ret < 0) {
             BlockErrorAction action =


@@ -192,10 +193,12 @@ static void coroutine_fn commit_run(void *opaque)
             }
         }
         /* Publish progress */
             }
         }
         /* Publish progress */

-        s->common.offset += n * BDRV_SECTOR_SIZE;
+        job_progress_update(&s->common.job, n);

 
 

-        if (copy && s->common.speed) {
-            delay_ns = ratelimit_calculate_delay(&s->limit, n);
+        if (copy) {
+            delay_ns = block_job_ratelimit_get_delay(&s->common, n);
+        } else {
+            delay_ns = 0;

         }
     }
 
         }
     }
 


@@ -204,27 +207,21 @@ static void coroutine_fn commit_run(void *opaque)
 out:
     qemu_vfree(buf);
 
 out:
     qemu_vfree(buf);
 

-    data = g_malloc(sizeof(*data));
-    data->ret = ret;
-    block_job_defer_to_main_loop(&s->common, commit_complete, data);
-}
-
-static void commit_set_speed(BlockJob *job, int64_t speed, Error **errp)
-{
-    CommitBlockJob *s = container_of(job, CommitBlockJob, common);
-
-    if (speed < 0) {
-        error_setg(errp, QERR_INVALID_PARAMETER, "speed");
-        return;
-    }
-    ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
+    return ret;

 }
 
 static const BlockJobDriver commit_job_driver = {
 }
 
 static const BlockJobDriver commit_job_driver = {

-    .instance_size = sizeof(CommitBlockJob),
-    .job_type      = BLOCK_JOB_TYPE_COMMIT,
-    .set_speed     = commit_set_speed,
-    .start         = commit_run,
+    .job_driver = {
+        .instance_size = sizeof(CommitBlockJob),
+        .job_type      = JOB_TYPE_COMMIT,
+        .free          = block_job_free,
+        .user_resume   = block_job_user_resume,
+        .drain         = block_job_drain,
+        .run           = commit_run,
+        .prepare       = commit_prepare,
+        .abort         = commit_abort,
+        .clean         = commit_clean
+    },

 };
 
 static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,
 };
 
 static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,


@@ -233,29 +230,15 @@ static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,
     return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
 }
 
     return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
 }
 

-static int64_t coroutine_fn bdrv_commit_top_get_block_status(
-    BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum,
-    BlockDriverState **file)
-{
-    *pnum = nb_sectors;
-    *file = bs->backing->bs;
-    return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
-           (sector_num << BDRV_SECTOR_BITS);
-}
-
-static void bdrv_commit_top_refresh_filename(BlockDriverState *bs, QDict *opts)
+static void bdrv_commit_top_refresh_filename(BlockDriverState *bs)

 {
 {

-    bdrv_refresh_filename(bs->backing->bs);

     pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
             bs->backing->bs->filename);
 }
 
     pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
             bs->backing->bs->filename);
 }
 

-static void bdrv_commit_top_close(BlockDriverState *bs)
-{
-}
-

 static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
                                        const BdrvChildRole *role,
 static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
                                        const BdrvChildRole *role,

+                                       BlockReopenQueue *reopen_queue,

                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
 {
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
 {


@@ -268,23 +251,19 @@ static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
 static BlockDriver bdrv_commit_top = {
     .format_name                = "commit_top",
     .bdrv_co_preadv             = bdrv_commit_top_preadv,
 static BlockDriver bdrv_commit_top = {
     .format_name                = "commit_top",
     .bdrv_co_preadv             = bdrv_commit_top_preadv,

-    .bdrv_co_get_block_status   = bdrv_commit_top_get_block_status,
+    .bdrv_co_block_status       = bdrv_co_block_status_from_backing,

     .bdrv_refresh_filename      = bdrv_commit_top_refresh_filename,
     .bdrv_refresh_filename      = bdrv_commit_top_refresh_filename,

-    .bdrv_close                 = bdrv_commit_top_close,

     .bdrv_child_perm            = bdrv_commit_top_child_perm,
 };
 
 void commit_start(const char *job_id, BlockDriverState *bs,
     .bdrv_child_perm            = bdrv_commit_top_child_perm,
 };
 
 void commit_start(const char *job_id, BlockDriverState *bs,

-                  BlockDriverState *base, BlockDriverState *top, int64_t speed,
+                  BlockDriverState *base, BlockDriverState *top,
+                  int creation_flags, int64_t speed,

                   BlockdevOnError on_error, const char *backing_file_str,
                   const char *filter_node_name, Error **errp)
 {
     CommitBlockJob *s;
                   BlockdevOnError on_error, const char *backing_file_str,
                   const char *filter_node_name, Error **errp)
 {
     CommitBlockJob *s;

-    BlockReopenQueue *reopen_queue = NULL;
-    int orig_overlay_flags;
-    int orig_base_flags;

     BlockDriverState *iter;
     BlockDriverState *iter;

-    BlockDriverState *overlay_bs;

     BlockDriverState *commit_top_bs = NULL;
     Error *local_err = NULL;
     int ret;
     BlockDriverState *commit_top_bs = NULL;
     Error *local_err = NULL;
     int ret;


@@ -295,35 +274,16 @@ void commit_start(const char *job_id, BlockDriverState *bs,
         return;
     }
 
         return;
     }
 

-    overlay_bs = bdrv_find_overlay(bs, top);
-
-    if (overlay_bs == NULL) {
-        error_setg(errp, "Could not find overlay image for %s:", top->filename);
-        return;
-    }
-
-    s = block_job_create(job_id, &commit_job_driver, bs, 0, BLK_PERM_ALL,
-                         speed, BLOCK_JOB_DEFAULT, NULL, NULL, errp);
+    s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
+                         speed, creation_flags, NULL, NULL, errp);

     if (!s) {
         return;
     }
 
     if (!s) {
         return;
     }
 

-    orig_base_flags    = bdrv_get_flags(base);
-    orig_overlay_flags = bdrv_get_flags(overlay_bs);
-
-    /* convert base & overlay_bs to r/w, if necessary */
-    if (!(orig_base_flags & BDRV_O_RDWR)) {
-        reopen_queue = bdrv_reopen_queue(reopen_queue, base, NULL,
-                                         orig_base_flags | BDRV_O_RDWR);
-    }
-    if (!(orig_overlay_flags & BDRV_O_RDWR)) {
-        reopen_queue = bdrv_reopen_queue(reopen_queue, overlay_bs, NULL,
-                                         orig_overlay_flags | BDRV_O_RDWR);
-    }
-    if (reopen_queue) {
-        bdrv_reopen_multiple(bdrv_get_aio_context(bs), reopen_queue, &local_err);
-        if (local_err != NULL) {
-            error_propagate(errp, local_err);
+    /* convert base to r/w, if necessary */
+    s->base_read_only = bdrv_is_read_only(base);
+    if (s->base_read_only) {
+        if (bdrv_reopen_set_read_only(base, false, errp) != 0) {

             goto fail;
         }
     }
             goto fail;
         }
     }


@@ -335,26 +295,19 @@ void commit_start(const char *job_id, BlockDriverState *bs,
     if (commit_top_bs == NULL) {
         goto fail;
     }
     if (commit_top_bs == NULL) {
         goto fail;
     }

+    if (!filter_node_name) {
+        commit_top_bs->implicit = true;
+    }

     commit_top_bs->total_sectors = top->total_sectors;
     commit_top_bs->total_sectors = top->total_sectors;

-    bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top));

 
 

-    bdrv_set_backing_hd(commit_top_bs, top, &local_err);
+    bdrv_append(commit_top_bs, top, &local_err);

     if (local_err) {
     if (local_err) {

-        bdrv_unref(commit_top_bs);
-        commit_top_bs = NULL;
-        error_propagate(errp, local_err);
-        goto fail;
-    }
-    bdrv_set_backing_hd(overlay_bs, commit_top_bs, &local_err);
-    if (local_err) {
-        bdrv_unref(commit_top_bs);

         commit_top_bs = NULL;
         error_propagate(errp, local_err);
         goto fail;
     }
 
     s->commit_top_bs = commit_top_bs;
         commit_top_bs = NULL;
         error_propagate(errp, local_err);
         goto fail;
     }
 
     s->commit_top_bs = commit_top_bs;

-    bdrv_unref(commit_top_bs);

 
     /* Block all nodes between top and base, because they will
      * disappear from the chain after this operation. */
 
     /* Block all nodes between top and base, because they will
      * disappear from the chain after this operation. */


@@ -372,20 +325,18 @@ void commit_start(const char *job_id, BlockDriverState *bs,
         }
     }
 
         }
     }
 

-    ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
-    if (ret < 0) {
+    if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) {

         goto fail;
     }
         goto fail;
     }

+    s->chain_frozen = true;

 
 

-    /* overlay_bs must be blocked because it needs to be modified to
-     * update the backing image string. */
-    ret = block_job_add_bdrv(&s->common, "overlay of top", overlay_bs,
-                             BLK_PERM_GRAPH_MOD, BLK_PERM_ALL, errp);
+    ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);

     if (ret < 0) {
         goto fail;
     }
 
     if (ret < 0) {
         goto fail;
     }
 

-    s->base = blk_new(BLK_PERM_CONSISTENT_READ
+    s->base = blk_new(s->common.job.aio_context,
+                      BLK_PERM_CONSISTENT_READ

                       | BLK_PERM_WRITE
                       | BLK_PERM_RESIZE,
                       BLK_PERM_CONSISTENT_READ
                       | BLK_PERM_WRITE
                       | BLK_PERM_RESIZE,
                       BLK_PERM_CONSISTENT_READ


@@ -395,42 +346,45 @@ void commit_start(const char *job_id, BlockDriverState *bs,
     if (ret < 0) {
         goto fail;
     }
     if (ret < 0) {
         goto fail;
     }

+    s->base_bs = base;

 
     /* Required permissions are already taken with block_job_add_bdrv() */
 
     /* Required permissions are already taken with block_job_add_bdrv() */

-    s->top = blk_new(0, BLK_PERM_ALL);
+    s->top = blk_new(s->common.job.aio_context, 0, BLK_PERM_ALL);

     ret = blk_insert_bs(s->top, top, errp);
     if (ret < 0) {
         goto fail;
     }
 
     ret = blk_insert_bs(s->top, top, errp);
     if (ret < 0) {
         goto fail;
     }
 

-    s->active = bs;
-
-    s->base_flags          = orig_base_flags;
-    s->orig_overlay_flags  = orig_overlay_flags;
-

     s->backing_file_str = g_strdup(backing_file_str);
     s->backing_file_str = g_strdup(backing_file_str);

-

     s->on_error = on_error;
 
     trace_commit_start(bs, base, top, s);
     s->on_error = on_error;
 
     trace_commit_start(bs, base, top, s);

-    block_job_start(&s->common);
+    job_start(&s->common.job);

     return;
 
 fail:
     return;
 
 fail:

+    if (s->chain_frozen) {
+        bdrv_unfreeze_backing_chain(commit_top_bs, base);
+    }

     if (s->base) {
         blk_unref(s->base);
     }
     if (s->top) {
         blk_unref(s->top);
     }
     if (s->base) {
         blk_unref(s->base);
     }
     if (s->top) {
         blk_unref(s->top);
     }

+    if (s->base_read_only) {
+        bdrv_reopen_set_read_only(base, true, NULL);
+    }
+    job_early_fail(&s->common.job);
+    /* commit_top_bs has to be replaced after deleting the block job,
+     * otherwise this would fail because of lack of permissions. */

     if (commit_top_bs) {
     if (commit_top_bs) {

-        bdrv_set_backing_hd(overlay_bs, top, &error_abort);
+        bdrv_replace_node(commit_top_bs, top, &error_abort);

     }
     }

-    block_job_unref(&s->common);

 }
 
 
 }
 
 

-#define COMMIT_BUF_SECTORS 2048
+#define COMMIT_BUF_SIZE (2048 * BDRV_SECTOR_SIZE)

 
 /* commit COW file into the raw image */
 int bdrv_commit(BlockDriverState *bs)
 
 /* commit COW file into the raw image */
 int bdrv_commit(BlockDriverState *bs)


@@ -439,8 +393,10 @@ int bdrv_commit(BlockDriverState *bs)
     BlockDriverState *backing_file_bs = NULL;
     BlockDriverState *commit_top_bs = NULL;
     BlockDriver *drv = bs->drv;
     BlockDriverState *backing_file_bs = NULL;
     BlockDriverState *commit_top_bs = NULL;
     BlockDriver *drv = bs->drv;

-    int64_t sector, total_sectors, length, backing_length;
-    int n, ro, open_flags;
+    AioContext *ctx;
+    int64_t offset, length, backing_length;
+    int ro;
+    int64_t n;

     int ret = 0;
     uint8_t *buf = NULL;
     Error *local_err = NULL;
     int ret = 0;
     uint8_t *buf = NULL;
     Error *local_err = NULL;


@@ -458,16 +414,16 @@ int bdrv_commit(BlockDriverState *bs)
     }
 
     ro = bs->backing->bs->read_only;
     }
 
     ro = bs->backing->bs->read_only;

-    open_flags =  bs->backing->bs->open_flags;

 
     if (ro) {
 
     if (ro) {

-        if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) {
+        if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) {

             return -EACCES;
         }
     }
 
             return -EACCES;
         }
     }
 

-    src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
-    backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
+    ctx = bdrv_get_aio_context(bs);
+    src = blk_new(ctx, BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
+    backing = blk_new(ctx, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);

 
     ret = blk_insert_bs(src, bs, &local_err);
     if (ret < 0) {
 
     ret = blk_insert_bs(src, bs, &local_err);
     if (ret < 0) {


@@ -484,7 +440,6 @@ int bdrv_commit(BlockDriverState *bs)
         error_report_err(local_err);
         goto ro_cleanup;
     }
         error_report_err(local_err);
         goto ro_cleanup;
     }

-    bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs));

 
     bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);
     bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);
 
     bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);
     bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);


@@ -511,37 +466,33 @@ int bdrv_commit(BlockDriverState *bs)
      * grow the backing file image if possible.  If not possible,
      * we must return an error */
     if (length > backing_length) {
      * grow the backing file image if possible.  If not possible,
      * we must return an error */
     if (length > backing_length) {

-        ret = blk_truncate(backing, length, &local_err);
+        ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err);

         if (ret < 0) {
             error_report_err(local_err);
             goto ro_cleanup;
         }
     }
 
         if (ret < 0) {
             error_report_err(local_err);
             goto ro_cleanup;
         }
     }
 

-    total_sectors = length >> BDRV_SECTOR_BITS;
-

     /* blk_try_blockalign() for src will choose an alignment that works for
      * backing as well, so no need to compare the alignment manually. */
     /* blk_try_blockalign() for src will choose an alignment that works for
      * backing as well, so no need to compare the alignment manually. */

-    buf = blk_try_blockalign(src, COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
+    buf = blk_try_blockalign(src, COMMIT_BUF_SIZE);

     if (buf == NULL) {
         ret = -ENOMEM;
         goto ro_cleanup;
     }
 
     if (buf == NULL) {
         ret = -ENOMEM;
         goto ro_cleanup;
     }
 

-    for (sector = 0; sector < total_sectors; sector += n) {
-        ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n);
+    for (offset = 0; offset < length; offset += n) {
+        ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n);

         if (ret < 0) {
             goto ro_cleanup;
         }
         if (ret) {
         if (ret < 0) {
             goto ro_cleanup;
         }
         if (ret) {

-            ret = blk_pread(src, sector * BDRV_SECTOR_SIZE, buf,
-                            n * BDRV_SECTOR_SIZE);
+            ret = blk_pread(src, offset, buf, n);

             if (ret < 0) {
                 goto ro_cleanup;
             }
 
             if (ret < 0) {
                 goto ro_cleanup;
             }
 

-            ret = blk_pwrite(backing, sector * BDRV_SECTOR_SIZE, buf,
-                             n * BDRV_SECTOR_SIZE, 0);
+            ret = blk_pwrite(backing, offset, buf, n, 0);

             if (ret < 0) {
                 goto ro_cleanup;
             }
             if (ret < 0) {
                 goto ro_cleanup;
             }


@@ -575,7 +526,7 @@ ro_cleanup:
 
     if (ro) {
         /* ignoring error return here */
 
     if (ro) {
         /* ignoring error return here */

-        bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL);
+        bdrv_reopen_set_read_only(bs->backing->bs, true, NULL);

     }
 
     return ret;
     }
 
     return ret;