dm mpath: support discard

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Enable discard support in the DM multipath target.

This discard support depends on a few discard-specific fixes to the
block layer's request stacking driver methods.

Discard requests are optional so don't allow a failed discard to trigger
path failures.  If there is a real problem with a given path the
barriers associated with the discard (either before or after the
discard) will cause path failure.  That said, unconditionally passing
discard failures up the stack is not ideal.  This must be fixed once DM
has more information about the nature of the underlying storage failure.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>

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Mike Snitzer 2010-08-12 04:14:32 +01:00 • committed by Alasdair G Kergon

parent 7b76ec11fe

commit 959eb4e559

1 changed files with 10 additions and 0 deletions

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drivers/md/dm-mpath.c

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