| Message ID | 1554747741-918964-2-git-send-email-andrey.shinkevich@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block/stream: get rid of the base | expand |
08.04.2019 21:22, Andrey Shinkevich wrote: > 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 crash. > > 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>
On Mon 08 Apr 2019 08:22:19 PM CEST, Andrey Shinkevich wrote: > * 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 > + * between BASE and TOP (TOP included). To check the BASE image, set the > + * 'include_base' to 'true'. The 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. I'm not a native speaker but that sounds a bit odd to me. Alternative: * Return true 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 false otherwise, or negative errno on * failure. > - while (intermediate && intermediate != base) { > + while (include_base || intermediate != base) { > int64_t pnum_inter; > int64_t size_inter; > > @@ -2360,6 +2364,10 @@ int bdrv_is_allocated_above(BlockDriverState *top, > n = pnum_inter; > } > > + if (intermediate == base) { > + break; > + } > + > intermediate = backing_bs(intermediate); I find that the new condition + the break make things a bit less readable. I think it would be simpler with something like this: BlockDriverState *stop_at = include_base ? backing_bs(base) : base; while (intermediate != stop_at) { ... } (stop_at is a terrible name, but I can't think of anything better at the moment) Berto
09.04.2019 17:18, Alberto Garcia wrote: > On Mon 08 Apr 2019 08:22:19 PM CEST, Andrey Shinkevich wrote: >> * 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 >> + * between BASE and TOP (TOP included). To check the BASE image, set the >> + * 'include_base' to 'true'. The 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. > > I'm not a native speaker but that sounds a bit odd to me. > > Alternative: > > * Return true 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 false otherwise, or negative errno on > * failure. > >> - while (intermediate && intermediate != base) { >> + while (include_base || intermediate != base) { >> int64_t pnum_inter; >> int64_t size_inter; >> >> @@ -2360,6 +2364,10 @@ int bdrv_is_allocated_above(BlockDriverState *top, >> n = pnum_inter; >> } >> >> + if (intermediate == base) { >> + break; >> + } >> + >> intermediate = backing_bs(intermediate); > > I find that the new condition + the break make things a bit less > readable. I think it would be simpler with something like this: > > BlockDriverState *stop_at = include_base ? backing_bs(base) : base; > > while (intermediate != stop_at) { > ... > } > But in this way you return back dependence on base, which we don't freeze and which may disappear on some iteration. We should not touch backing_bs(base) in any way.
On Tue 09 Apr 2019 04:43:12 PM CEST, Vladimir Sementsov-Ogievskiy wrote: >>> - while (intermediate && intermediate != base) { >>> + while (include_base || intermediate != base) { >>> int64_t pnum_inter; >>> int64_t size_inter; >>> >>> @@ -2360,6 +2364,10 @@ int bdrv_is_allocated_above(BlockDriverState *top, >>> n = pnum_inter; >>> } >>> >>> + if (intermediate == base) { >>> + break; >>> + } >>> + >>> intermediate = backing_bs(intermediate); >> >> I find that the new condition + the break make things a bit less >> readable. I think it would be simpler with something like this: >> >> BlockDriverState *stop_at = include_base ? backing_bs(base) : base; >> >> while (intermediate != stop_at) { >> ... >> } >> > > But in this way you return back dependence on base, which we don't > freeze and which may disappear on some iteration. We should not touch > backing_bs(base) in any way. Ok, I see. Reviewed-by: Alberto Garcia <berto@igalia.com> (feel free to edit the comment with my suggestion, or leave it as it is if you prefer) Berto
diff --git a/block/commit.c b/block/commit.c index ba60fef..1bd5284 100644 --- a/block/commit.c +++ b/block/commit.c @@ -177,7 +177,7 @@ 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 dfc153b..1ed4164 100644 --- a/block/io.c +++ b/block/io.c @@ -2317,7 +2317,8 @@ 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 + * between BASE and TOP (TOP included). To check the BASE image, set the + * 'include_base' to 'true'. The 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. * @@ -2331,14 +2332,17 @@ 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; @@ -2360,6 +2364,10 @@ 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 ff15cfb..923548f 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -807,7 +807,7 @@ 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/replication.c b/block/replication.c index 3d4dedd..fc8d2ad 100644 --- a/block/replication.c +++ b/block/replication.c @@ -272,7 +272,7 @@ 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 bfaebb8..0920092 100644 --- a/block/stream.c +++ b/block/stream.c @@ -162,7 +162,7 @@ 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 c7a2619..f98e858 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -447,7 +447,8 @@ 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,
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 crash. Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> --- block/commit.c | 2 +- block/io.c | 14 +++++++++++--- block/mirror.c | 2 +- block/replication.c | 2 +- block/stream.c | 2 +- include/block/block.h | 3 ++- 6 files changed, 17 insertions(+), 8 deletions(-)