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| author | Kevin Wolf <kwolf@redhat.com> | 2010-05-28 12:21:27 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2010-05-28 13:29:16 +0200 |
| commit | 86fa8da83771238de55dc44819a1a27bafef5353 (patch) | |
| tree | cd890a555fd8217c6ac6d8b33e5221bc1aa24447 /block/qcow2-refcount.c | |
| parent | 25408c09502be036e5575754fe54019ed4ed5dfa (diff) | |
| download | qemu-86fa8da83771238de55dc44819a1a27bafef5353.tar.gz qemu-86fa8da83771238de55dc44819a1a27bafef5353.tar.bz2 qemu-86fa8da83771238de55dc44819a1a27bafef5353.zip | |
qcow2: Fix corruption after error in update_refcount
After it is done with updating refcounts in the cache, update_refcount writes
all changed entries to disk. If a refcount block allocation fails, however,
there was no change yet and therefore first_index = last_index = -1. Don't
treat -1 as a normal sector index (resulting in a 512 byte write!) but return
without updating anything in this case.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2-refcount.c')
| -rw-r--r-- | block/qcow2-refcount.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 5b7cda4774..22b0b45ff7 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -417,6 +417,10 @@ static int write_refcount_block_entries(BlockDriverState *bs, return 0; } + if (first_index < 0) { + return 0; + } + first_index &= ~(REFCOUNTS_PER_SECTOR - 1); last_index = (last_index + REFCOUNTS_PER_SECTOR) & ~(REFCOUNTS_PER_SECTOR - 1); |