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author | Mikulas Patocka <mpatocka@redhat.com> | 2009-04-02 19:55:26 +0100 |
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committer | Alasdair G Kergon <agk@redhat.com> | 2009-04-02 19:55:26 +0100 |
commit | 35bf659b008e83e725dcd30f542e38461dbb867c (patch) | |
tree | 40be2f357f0905573bd4d21ff59e0db3cda26442 /samples | |
parent | c66213921c816f6b1b16a84911618ba9a363b134 (diff) |
dm snapshot: avoid having two exceptions for the same chunk
We need to check if the exception was completed after dropping the lock.
After regaining the lock, __find_pending_exception checks if the exception
was already placed into &s->pending hash.
But we don't check if the exception was already completed and placed into
&s->complete hash. If the process waiting in alloc_pending_exception was
delayed at this point because of a scheduling latency and the exception
was meanwhile completed, we'd miss that and allocate another pending
exception for already completed chunk.
It would lead to a situation where two records for the same chunk exist
and potential data corruption because multiple snapshot I/Os to the
affected chunk could be redirected to different locations in the
snapshot.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'samples')
0 files changed, 0 insertions, 0 deletions