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block: include base when checking image chain for block allocation

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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 <vsementsov@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
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 <mreitz@redhat.com>
This commit is contained in:
Andrey Shinkevich 2019-05-29 20:56:14 +03:00 committed by Max Reitz
parent d24f80234b
commit 170d3bd341
8 changed files with 24 additions and 13 deletions
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2
block/commit.c
View File

@ -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);

21
block/io.c
View File

@ -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);
}

2
block/mirror.c
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@ -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;
}

3
block/qcow2.c
View File

@ -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)

2
block/replication.c
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@ -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);

2
block/stream.c
View File

@ -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 */

3
include/block/block.h
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@ -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,

2
qemu-img.c
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@ -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));