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| author | NeilBrown <neilb@suse.de> | 2009-02-25 13:18:47 +1100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2009-02-25 13:18:47 +1100 |
| commit | 73d5c38a9536142e062c35997b044e89166e063b (patch) | |
| tree | 68fd385cbdee1fa75269974ef210d53a0ae5e311 /drivers/md/raid10.c | |
| parent | 78200d45cde2a79c0d0ae0407883bb264caa3c18 (diff) | |
| download | linux-73d5c38a9536142e062c35997b044e89166e063b.tar.gz linux-73d5c38a9536142e062c35997b044e89166e063b.tar.bz2 linux-73d5c38a9536142e062c35997b044e89166e063b.zip | |
md: avoid races when stopping resync.
There has been a race in raid10 and raid1 for a long time
which has only recently started showing up due to a scheduler changed.
When a sync_read request finishes, as soon as reschedule_retry
is called, another thread can mark the resync request as having
completed, so md_do_sync can finish, ->stop can be called, and
->conf can be freed. So using conf after reschedule_retry is not
safe.
Similarly, when finishing a sync_write, calling md_done_sync must be
the last thing we do, as it allows a chain of events which will free
conf and other data structures.
The first of these requires action in raid10.c
The second requires action in raid1.c and raid10.c
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/raid10.c')
| -rw-r--r-- | drivers/md/raid10.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index e1feb87afc6c..7301631abe04 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1236,6 +1236,7 @@ static void end_sync_read(struct bio *bio, int error) /* for reconstruct, we always reschedule after a read. * for resync, only after all reads */ + rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); if (test_bit(R10BIO_IsRecover, &r10_bio->state) || atomic_dec_and_test(&r10_bio->remaining)) { /* we have read all the blocks, @@ -1243,7 +1244,6 @@ static void end_sync_read(struct bio *bio, int error) */ reschedule_retry(r10_bio); } - rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); } static void end_sync_write(struct bio *bio, int error) @@ -1264,11 +1264,13 @@ static void end_sync_write(struct bio *bio, int error) update_head_pos(i, r10_bio); + rdev_dec_pending(conf->mirrors[d].rdev, mddev); while (atomic_dec_and_test(&r10_bio->remaining)) { if (r10_bio->master_bio == NULL) { /* the primary of several recovery bios */ - md_done_sync(mddev, r10_bio->sectors, 1); + sector_t s = r10_bio->sectors; put_buf(r10_bio); + md_done_sync(mddev, s, 1); break; } else { r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; @@ -1276,7 +1278,6 @@ static void end_sync_write(struct bio *bio, int error) r10_bio = r10_bio2; } } - rdev_dec_pending(conf->mirrors[d].rdev, mddev); } /* |