From 170d3bd341b3955f10b40b4569f66bf3d4dbc4a0 Mon Sep 17 00:00:00 2001 From: Andrey Shinkevich Date: Wed, 29 May 2019 20:56:14 +0300 Subject: [PATCH] block: include base when checking image chain for block allocation This patch is used in the 'block/stream: introduce a bottom node' that is following. Instead of the base node, the caller may pass the node that has the base as its backing image to the function bdrv_is_allocated_above() with a new parameter include_base = true and get rid of the dependency on the base that may change during commit/stream parallel jobs. Now, if the specified base is not found in the backing image chain, the QEMU will abort. Suggested-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Andrey Shinkevich Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Alberto Garcia Message-id: 1559152576-281803-2-git-send-email-andrey.shinkevich@virtuozzo.com [mreitz: Squashed in the following as a rebase on conflicting patches:] Message-id: e3cf99ae-62e9-8b6e-5a06-d3c8b9363b85@redhat.com Signed-off-by: Max Reitz --- block/commit.c | 2 +- block/io.c | 21 +++++++++++++++------ block/mirror.c | 2 +- block/qcow2.c | 3 ++- block/replication.c | 2 +- block/stream.c | 2 +- include/block/block.h | 3 ++- qemu-img.c | 2 +- 8 files changed, 24 insertions(+), 13 deletions(-) diff --git a/block/commit.c b/block/commit.c index 212c6f639e..ca7e408b26 100644 --- a/block/commit.c +++ b/block/commit.c @@ -174,7 +174,7 @@ static int coroutine_fn commit_run(Job *job, Error **errp) break; } /* Copy if allocated above the base */ - ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base), + ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base), false, offset, COMMIT_BUFFER_SIZE, &n); copy = (ret == 1); trace_commit_one_iteration(s, offset, n, ret); diff --git a/block/io.c b/block/io.c index 9ba1bada36..24a18759fd 100644 --- a/block/io.c +++ b/block/io.c @@ -2295,10 +2295,11 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset, /* * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] * - * Return true if (a prefix of) the given range is allocated in any image - * between BASE and TOP (inclusive). BASE can be NULL to check if the given - * offset is allocated in any image of the chain. Return false otherwise, - * or negative errno on failure. + * Return 1 if (a prefix of) the given range is allocated in any image + * between BASE and TOP (BASE is only included if include_base is set). + * BASE can be NULL to check if the given offset is allocated in any + * image of the chain. Return 0 otherwise, or negative errno on + * failure. * * 'pnum' is set to the number of bytes (including and immediately * following the specified offset) that are known to be in the same @@ -2310,17 +2311,21 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset, */ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, - int64_t offset, int64_t bytes, int64_t *pnum) + bool include_base, int64_t offset, + int64_t bytes, int64_t *pnum) { BlockDriverState *intermediate; int ret; int64_t n = bytes; + assert(base || !include_base); + intermediate = top; - while (intermediate && intermediate != base) { + while (include_base || intermediate != base) { int64_t pnum_inter; int64_t size_inter; + assert(intermediate); ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter); if (ret < 0) { return ret; @@ -2339,6 +2344,10 @@ int bdrv_is_allocated_above(BlockDriverState *top, n = pnum_inter; } + if (intermediate == base) { + break; + } + intermediate = backing_bs(intermediate); } diff --git a/block/mirror.c b/block/mirror.c index d17be4cdbc..2fcec70e35 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -808,7 +808,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) return 0; } - ret = bdrv_is_allocated_above(bs, base, offset, bytes, &count); + ret = bdrv_is_allocated_above(bs, base, false, offset, bytes, &count); if (ret < 0) { return ret; } diff --git a/block/qcow2.c b/block/qcow2.c index 9396d490d5..2a59eb27fe 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2148,7 +2148,8 @@ static bool is_unallocated(BlockDriverState *bs, int64_t offset, int64_t bytes) { int64_t nr; return !bytes || - (!bdrv_is_allocated_above(bs, NULL, offset, bytes, &nr) && nr == bytes); + (!bdrv_is_allocated_above(bs, NULL, false, offset, bytes, &nr) && + nr == bytes); } static bool is_zero_cow(BlockDriverState *bs, QCowL2Meta *m) diff --git a/block/replication.c b/block/replication.c index b41bc507c0..23b2993d74 100644 --- a/block/replication.c +++ b/block/replication.c @@ -275,7 +275,7 @@ static coroutine_fn int replication_co_writev(BlockDriverState *bs, while (remaining_sectors > 0) { int64_t count; - ret = bdrv_is_allocated_above(top->bs, base->bs, + ret = bdrv_is_allocated_above(top->bs, base->bs, false, sector_num * BDRV_SECTOR_SIZE, remaining_sectors * BDRV_SECTOR_SIZE, &count); diff --git a/block/stream.c b/block/stream.c index 1a906fd860..97fddb2608 100644 --- a/block/stream.c +++ b/block/stream.c @@ -160,7 +160,7 @@ static int coroutine_fn stream_run(Job *job, Error **errp) } else if (ret >= 0) { /* Copy if allocated in the intermediate images. Limit to the * known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). */ - ret = bdrv_is_allocated_above(backing_bs(bs), base, + ret = bdrv_is_allocated_above(backing_bs(bs), base, false, offset, n, &n); /* Finish early if end of backing file has been reached */ diff --git a/include/block/block.h b/include/block/block.h index f9415ed740..734c9d2f76 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -449,7 +449,8 @@ int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base, int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, int64_t *pnum); int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, - int64_t offset, int64_t bytes, int64_t *pnum); + bool include_base, int64_t offset, int64_t bytes, + int64_t *pnum); bool bdrv_is_read_only(BlockDriverState *bs); int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, diff --git a/qemu-img.c b/qemu-img.c index 158b3a505f..79983772de 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3518,7 +3518,7 @@ static int img_rebase(int argc, char **argv) * to take action */ ret = bdrv_is_allocated_above(backing_bs(bs), prefix_chain_bs, - offset, n, &n); + false, offset, n, &n); if (ret < 0) { error_report("error while reading image metadata: %s", strerror(-ret));