diff options
| -rw-r--r-- | block.c | 6 | ||||
| -rw-r--r-- | block/io.c | 8 | ||||
| -rw-r--r-- | blockdev.c | 2 | ||||
| -rw-r--r-- | include/block/block_int.h | 11 |
4 files changed, 15 insertions, 12 deletions
@@ -1300,7 +1300,9 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, goto fail_opts; } - assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */ + /* bdrv_new() and bdrv_close() make it so */ + assert(atomic_read(&bs->copy_on_read) == 0); + if (bs->open_flags & BDRV_O_COPY_ON_READ) { if (!bs->read_only) { bdrv_enable_copy_on_read(bs); @@ -3063,7 +3065,7 @@ static void bdrv_close(BlockDriverState *bs) g_free(bs->opaque); bs->opaque = NULL; - bs->copy_on_read = 0; + atomic_set(&bs->copy_on_read, 0); bs->backing_file[0] = '\0'; bs->backing_format[0] = '\0'; bs->total_sectors = 0; @@ -130,13 +130,13 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) */ void bdrv_enable_copy_on_read(BlockDriverState *bs) { - bs->copy_on_read++; + atomic_inc(&bs->copy_on_read); } void bdrv_disable_copy_on_read(BlockDriverState *bs) { - assert(bs->copy_on_read > 0); - bs->copy_on_read--; + int old = atomic_fetch_dec(&bs->copy_on_read); + assert(old >= 1); } /* Check if any requests are in-flight (including throttled requests) */ @@ -1144,7 +1144,7 @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child, bdrv_inc_in_flight(bs); /* Don't do copy-on-read if we read data before write operation */ - if (bs->copy_on_read && !(flags & BDRV_REQ_NO_SERIALISING)) { + if (atomic_read(&bs->copy_on_read) && !(flags & BDRV_REQ_NO_SERIALISING)) { flags |= BDRV_REQ_COPY_ON_READ; } @@ -1791,7 +1791,7 @@ static void external_snapshot_commit(BlkActionState *common) /* We don't need (or want) to use the transactional * bdrv_reopen_multiple() across all the entries at once, because we * don't want to abort all of them if one of them fails the reopen */ - if (!state->old_bs->copy_on_read) { + if (!atomic_read(&state->old_bs->copy_on_read)) { bdrv_reopen(state->old_bs, state->old_bs->open_flags & ~BDRV_O_RDWR, NULL); } diff --git a/include/block/block_int.h b/include/block/block_int.h index cb78c4f..49f2ebb 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -595,11 +595,6 @@ struct BlockDriverState { /* Protected by AioContext lock */ - /* If true, copy read backing sectors into image. Can be >1 if more - * than one client has requested copy-on-read. - */ - int copy_on_read; - /* If we are reading a disk image, give its size in sectors. * Generally read-only; it is written to by load_snapshot and * save_snaphost, but the block layer is quiescent during those. @@ -633,6 +628,12 @@ struct BlockDriverState { QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; + /* If true, copy read backing sectors into image. Can be >1 if more + * than one client has requested copy-on-read. Accessed with atomic + * ops. + */ + int copy_on_read; + /* do we need to tell the quest if we have a volatile write cache? */ int enable_write_cache; |