diff options
Diffstat (limited to 'block/io.c')
| -rw-r--r-- | block/io.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/block/io.c b/block/io.c index 7e87a42b8e..01a3c4eac5 100644 --- a/block/io.c +++ b/block/io.c @@ -3039,6 +3039,8 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, { BlockDriverState *bs = child->bs; BlockDriver *drv = bs->drv; + BdrvTrackedRequest req; + int64_t old_size, new_bytes; int ret; assert(child->perm & BLK_PERM_RESIZE); @@ -3053,7 +3055,28 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, return -EINVAL; } + old_size = bdrv_getlength(bs); + if (old_size < 0) { + error_setg_errno(errp, -old_size, "Failed to get old image size"); + return old_size; + } + + if (offset > old_size) { + new_bytes = offset - old_size; + } else { + new_bytes = 0; + } + bdrv_inc_in_flight(bs); + tracked_request_begin(&req, bs, offset, new_bytes, BDRV_TRACKED_TRUNCATE); + + /* If we are growing the image and potentially using preallocation for the + * new area, we need to make sure that no write requests are made to it + * concurrently or they might be overwritten by preallocation. */ + if (new_bytes) { + mark_request_serialising(&req, 1); + wait_serialising_requests(&req); + } if (!drv->bdrv_co_truncate) { if (bs->file && drv->is_filter) { @@ -3087,7 +3110,9 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, atomic_inc(&bs->write_gen); out: + tracked_request_end(&req); bdrv_dec_in_flight(bs); + return ret; } |