[PATCH v4 2/3] dm mpath: propagate target errors immediately

Hannes Reinecke
2011-01-18T09:13:14Z

DM now has more information about the nature of the underlying storage
failure. Path failure is avoided if a request failed due to a target
error. Instead the target error is immediately passed up the stack.

Discard requests that fail due to non-target errors may now be retried.

Errors restricted to the path will be retried or returned if no
paths are available, irregarding the no_path_retry setting.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/md/dm-mpath.c | 22 ++++++++++------------
1 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 487ecda..0781683 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1270,24 +1270,22 @@ static int do_end_io(struct multipath *m, struct request *clone,
if (!error && !clone->errors)
return 0; /* I/O complete */

- if (error == -EOPNOTSUPP)
- return error;
-
- if (clone->cmd_flags & REQ_DISCARD)
- /*
- * Pass all discard request failures up.
- * FIXME: only fail_path if the discard failed due to a
- * transport problem. This requires precise understanding
- * of the underlying failure (e.g. the SCSI sense).
- */
+ if (error == -EOPNOTSUPP || error == -EREMOTEIO)
return error;

if (mpio->pgpath)
fail_path(mpio->pgpath);

spin_lock_irqsave(&m->lock, flags);
- if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m))
- r = -EIO;
+ if (!m->nr_valid_paths) {
+ if (!m->queue_if_no_path) {
+ if (!__must_push_back(m))
+ r = -EIO;
+ } else {
+ if (error == -EBADE)
+ r = error;
+ }
+ }
spin_unlock_irqrestore(&m->lock, flags);

return r;
--
1.6.0.2