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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2019-10-30 20:29:48 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-11-01 08:43:20 -0600 |
| commit | efcfec579f6139528c9e6925eca2bc4a36da65c6 (patch) | |
| tree | fcb52fe28df557856d7d4f78204d8952f85a9693 /tools/perf/scripts/python/net_dropmonitor.py | |
| parent | a4414aedf4bc923c1faa24d72d14f14c2b93e48f (diff) | |
loop: fix no-unmap write-zeroes request behavior
Currently, if the loop device receives a WRITE_ZEROES request, it asks
the underlying filesystem to punch out the range. This behavior is
correct if unmapping is allowed. However, a NOUNMAP request means that
the caller doesn't want us to free the storage backing the range, so
punching out the range is incorrect behavior.
To satisfy a NOUNMAP | WRITE_ZEROES request, loop should ask the
underlying filesystem to FALLOC_FL_ZERO_RANGE, which is (according to
the fallocate documentation) required to ensure that the entire range is
backed by real storage, which suffices for our purposes.
Fixes: 19372e2769179dd ("loop: implement REQ_OP_WRITE_ZEROES")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'tools/perf/scripts/python/net_dropmonitor.py')
0 files changed, 0 insertions, 0 deletions