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author | Max Reitz <mreitz@redhat.com> | 2021-02-19 16:33:47 +0100 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2021-03-08 14:55:18 +0100 |
commit | 705dde27c6c53b73d2aa139b5b2a0ea490153e5b (patch) | |
tree | 8c8115d08239512606b60bea463ad061429299f6 /block/backup-top.c | |
parent | bdc4c4c5e372756a5ba3fb3a61e585b02f0dd7f4 (diff) | |
download | qemu-705dde27c6c53b73d2aa139b5b2a0ea490153e5b.zip qemu-705dde27c6c53b73d2aa139b5b2a0ea490153e5b.tar.gz qemu-705dde27c6c53b73d2aa139b5b2a0ea490153e5b.tar.bz2 |
backup-top: Refuse I/O in inactive state
When the backup-top node transitions from active to inactive in
bdrv_backup_top_drop(), the BlockCopyState is freed and the filtered
child is removed, so the node effectively becomes unusable.
However, noone told its I/O functions this, so they will happily
continue accessing bs->backing and s->bcs. Prevent that by aborting
early when s->active is false.
(After the preceding patch, the node should be gone after
bdrv_backup_top_drop(), so this should largely be a theoretical problem.
But still, better to be safe than sorry, and also I think it just makes
sense to check s->active in the I/O functions.)
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210219153348.41861-3-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/backup-top.c')
-rw-r--r-- | block/backup-top.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/block/backup-top.c b/block/backup-top.c index d1253e1..589e8b6 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -45,6 +45,12 @@ static coroutine_fn int backup_top_co_preadv( BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) { + BDRVBackupTopState *s = bs->opaque; + + if (!s->active) { + return -EIO; + } + return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); } @@ -54,6 +60,10 @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset, BDRVBackupTopState *s = bs->opaque; uint64_t off, end; + if (!s->active) { + return -EIO; + } + if (flags & BDRV_REQ_WRITE_UNCHANGED) { return 0; } |