Commit 170d3bd3 authored by Andrey Shinkevich's avatar Andrey Shinkevich Committed by Max Reitz
Browse files

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: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: default avatarAndrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarAlberto 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: default avatarMax Reitz <mreitz@redhat.com>
parent d24f8023

block/commit.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

block/io.c

+15 −6
Original line number Diff line number Diff line
@@ -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);

    }

block/mirror.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

        }

block/qcow2.c

+2 −1
Original line number Diff line number Diff line
@@ -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)

block/replication.c

+1 −1
Original line number Diff line number Diff line
@@ -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);