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| author | Christoph Hellwig <hch@lst.de> | 2015-05-22 16:14:04 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-05-22 17:58:57 +0300 |
| commit | 5f1b670d0bef508a5554d92525f5f6d00d640b38 (patch) | |
| tree | 18aaa4b5ead87568214b3d9c0f501d8a98c2a787 /fs | |
| parent | 326e1dbb57368087a36607aaebe9795b8d5453e5 (diff) | |
| download | linux-5f1b670d0bef508a5554d92525f5f6d00d640b38.tar.xz | |
block, dm: don't copy bios for request clones
Currently dm-multipath has to clone the bios for every request sent
to the lower devices, which wastes cpu cycles and ties down memory.
This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio
to not complete bios attached to a request, which we set on clone
requests similar to bios in a flush sequence. With this change I/O
errors on a path failure only get propagated to dm-multipath, which
can then either resubmit the I/O or complete the bios on the original
request.
I've done some basic testing of this on a Linux target with ALUA support,
and it survives path failures during I/O nicely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs')
0 files changed, 0 insertions, 0 deletions