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| author | NeilBrown <neilb@suse.de> | 2014-12-03 16:07:58 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-29 17:40:57 -0800 |
| commit | a4f2a8dd08e298cec7cf6317d788612ce2dd7144 (patch) | |
| tree | afee11f2d77aab6ee7bf1be02a210d137377dee8 | |
| parent | 23d5efc071f5f47257e5b33c41534a30b1099cc3 (diff) | |
| download | lwn-a4f2a8dd08e298cec7cf6317d788612ce2dd7144.tar.gz lwn-a4f2a8dd08e298cec7cf6317d788612ce2dd7144.zip | |
md/raid5: fetch_block must fetch all the blocks handle_stripe_dirtying wants.
commit 108cef3aa41669610e1836fe638812dd067d72de upstream.
It is critical that fetch_block() and handle_stripe_dirtying()
are consistent in their analysis of what needs to be loaded.
Otherwise raid5 can wait forever for a block that won't be loaded.
Currently when writing to a RAID5 that is resyncing, to a location
beyond the resync offset, handle_stripe_dirtying chooses a
reconstruct-write cycle, but fetch_block() assumes a
read-modify-write, and a lockup can happen.
So treat that case just like RAID6, just as we do in
handle_stripe_dirtying. RAID6 always does reconstruct-write.
This bug was introduced when the behaviour of handle_stripe_dirtying
was changed in 3.7, so the patch is suitable for any kernel since,
though it will need careful merging for some versions.
Cc: stable@vger.kernel.org (v3.7+)
Fixes: a7854487cd7128a30a7f4f5259de9f67d5efb95f
Reported-by: Henry Cai <henryplusplus@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/md/raid5.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 2332b5ced0dd..4daf5c03b33b 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2678,7 +2678,8 @@ static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s, (s->failed >= 2 && fdev[1]->toread) || (sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite && !test_bit(R5_OVERWRITE, &fdev[0]->flags)) || - (sh->raid_conf->level == 6 && s->failed && s->to_write))) { + ((sh->raid_conf->level == 6 || sh->sector >= sh->raid_conf->mddev->recovery_cp) + && s->failed && s->to_write))) { /* we would like to get this block, possibly by computing it, * otherwise read it if the backing disk is insync */ |