From: Mike Snitzer <snitzer@redhat.com>
To: dm-devel@redhat.com
Cc: linux-scsi@vger.kernel.org,
Mike Anderson <andmike@linux.vnet.ibm.com>,
Mike Christie <michaelc@cs.wisc.edu>
Subject: [PATCH v2] dm mpath: add feature flag to control call to blk_abort_queue
Date: Wed, 17 Nov 2010 23:40:22 -0500 [thread overview]
Message-ID: <1290055222-12320-1-git-send-email-snitzer@redhat.com> (raw)
In-Reply-To: <20101117215541.GA7785@redhat.com>
Add 'features' member to 'struct multipath' and introduce
MPF_ABORT_QUEUE as the first feature flag. If "abort_queue_on_failure"
is provided during mpath device configuration the MPF_ABORT_QUEUE
feature flag will be set and blk_abort_queue() will be called during
path failure to allow for lower latency path failures.
But this feature has been disabled by default due to a race (between
blk_abort_queue and scsi_request_fn) that can lead to list corruption,
from: https://www.redhat.com/archives/dm-devel/2010-November/msg00085.html
"the cmd gets blk_abort_queued/timedout run on it and the scsi eh
somehow is able to complete and run scsi_queue_insert while
scsi_request_fn is still trying to process the request."
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
---
drivers/md/dm-mpath.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
Index: linux-2.6/drivers/md/dm-mpath.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-mpath.c
+++ linux-2.6/drivers/md/dm-mpath.c
@@ -56,8 +56,14 @@ struct priority_group {
struct list_head pgpaths;
};
+/*
+ * Bits for the m->features
+ */
+#define MPF_ABORT_QUEUE 0
+
/* Multipath context */
struct multipath {
+ unsigned long features;
struct list_head list;
struct dm_target *ti;
@@ -146,7 +152,8 @@ static void deactivate_path(struct work_
struct pgpath *pgpath =
container_of(work, struct pgpath, deactivate_path);
- blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue);
+ if (test_bit(MPF_ABORT_QUEUE, &pgpath->pg->m->features))
+ blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue);
}
static struct priority_group *alloc_priority_group(void)
@@ -813,6 +820,11 @@ static int parse_features(struct arg_set
continue;
}
+ if (!strnicmp(param_name, MESG_STR("abort_queue_on_failure"))) {
+ set_bit(MPF_ABORT_QUEUE, &m->features);
+ continue;
+ }
+
if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
(argc >= 1)) {
r = read_param(_params + 1, shift(as),
@@ -1382,11 +1394,14 @@ static int multipath_status(struct dm_ta
DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count);
else {
DMEMIT("%u ", m->queue_if_no_path +
- (m->pg_init_retries > 0) * 2);
+ (m->pg_init_retries > 0) * 2 +
+ test_bit(MPF_ABORT_QUEUE, &m->features));
if (m->queue_if_no_path)
DMEMIT("queue_if_no_path ");
if (m->pg_init_retries)
DMEMIT("pg_init_retries %u ", m->pg_init_retries);
+ if (test_bit(MPF_ABORT_QUEUE, &m->features))
+ DMEMIT("abort_queue_on_failure ");
}
if (!m->hw_handler_name || type == STATUSTYPE_INFO)
next prev parent reply other threads:[~2010-11-18 4:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-12 5:23 block_abort_queue (blk_abort_request) racing with scsi_request_fn Mike Anderson
2010-11-10 7:09 ` [dm-devel] " Mike Christie
2010-11-10 7:30 ` Mike Christie
2010-11-10 16:30 ` Mike Anderson
2010-11-10 21:16 ` Mike Christie
2010-11-12 17:54 ` Mike Anderson
2010-11-16 21:39 ` Mike Snitzer
2010-11-17 17:49 ` [dm-devel] " Mike Anderson
2010-11-17 21:55 ` Mike Snitzer
2010-11-18 4:40 ` Mike Snitzer [this message]
2010-11-18 7:20 ` [PATCH v2] dm mpath: add feature flag to control call to blk_abort_queue Mike Anderson
2010-11-18 15:48 ` Mike Snitzer
2010-11-18 15:48 ` [PATCH v3] " Mike Snitzer
2010-11-18 19:16 ` (unknown), Mike Snitzer
2010-11-18 19:21 ` Mike Snitzer
2010-11-18 19:19 ` [PATCH v4] dm mpath: avoid call to blk_abort_queue by default Mike Snitzer
2010-11-18 20:07 ` [PATCH v5] " Mike Snitzer
2010-11-18 20:18 ` [dm-devel] " Alasdair G Kergon
2010-11-18 20:39 ` Mike Anderson
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