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| author | hui jiao <simonjiaoh@gmail.com> | 2014-06-05 11:34:24 +0800 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2014-06-05 17:18:19 +1000 |
| commit | 2844dc32ea67044b345221067207ce67ffe8da76 (patch) | |
| tree | 4f235e9eacd5a86110b70c39fa21673bb2916946 /drivers/md | |
| parent | d592a9969141e67a3874c808999a4db4bf82ed83 (diff) | |
| download | linux-2844dc32ea67044b345221067207ce67ffe8da76.tar.gz linux-2844dc32ea67044b345221067207ce67ffe8da76.tar.bz2 linux-2844dc32ea67044b345221067207ce67ffe8da76.zip | |
md/raid5: deadlock between retry_aligned_read with barrier io
A chunk aligned read increases counter active_aligned_reads and
decreases it after sub-device handle it successfully. But when a read
error occurs, the read redispatched by raid5d, and the
active_aligned_reads will not be decreased until we can grab a stripe
head in retry_aligned_read. Now suppose, a barrier io comes, set
conf->quiesce to 2, and wait until both active_stripes and
active_aligned_reads are zero. The retried chunk aligned read gets
stuck at get_active_stripe waiting until conf->quiesce becomes 0.
Retry_aligned_read and barrier io are waiting each other now.
One possible solution is that we ignore conf->quiesce, let the retried
aligned read finish. I reproduced this deadlock and test this patch on
centos6.0
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index d69fd9888c2c..ce421e3a3980 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5115,7 +5115,7 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio) /* already done this stripe */ continue; - sh = get_active_stripe(conf, sector, 0, 1, 0); + sh = get_active_stripe(conf, sector, 0, 1, 1); if (!sh) { /* failed to get a stripe - must wait */ |