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author | Neil Brown <neilb@suse.de> | 2007-02-08 14:20:29 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-09 09:25:46 -0800 |
commit | 387bb17374c5fa057462d00d4ba941d49f45de4d (patch) | |
tree | 85c68bbd2f077724563cfb26a3357d6679f12104 /drivers/md | |
parent | 6649a3863232eb2e2f15ea6c622bd8ceacf96d76 (diff) | |
download | linux-387bb17374c5fa057462d00d4ba941d49f45de4d.tar.gz linux-387bb17374c5fa057462d00d4ba941d49f45de4d.tar.bz2 linux-387bb17374c5fa057462d00d4ba941d49f45de4d.zip |
[PATCH] md: fix various bugs with aligned reads in RAID5
It is possible for raid5 to be sent a bio that is too big for an underlying
device. So if it is a READ that we pass stright down to a device, it will
fail and confuse RAID5.
So in 'chunk_aligned_read' we check that the bio fits within the parameters
for the target device and if it doesn't fit, fall back on reading through
the stripe cache and making lots of one-page requests.
Note that this is the earliest time we can check against the device because
earlier we don't have a lock on the device, so it could change underneath
us.
Also, the code for handling a retry through the cache when a read fails has
not been tested and was badly broken. This patch fixes that code.
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: "Kai" <epimetreus@fastmail.fm>
Cc: <stable@suse.de>
Cc: <org@suse.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/md')
-rw-r--r-- | drivers/md/raid5.c | 42 |
1 files changed, 39 insertions, 3 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 467c16982d02..11c3d7bfa797 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2620,7 +2620,7 @@ static struct bio *remove_bio_from_retry(raid5_conf_t *conf) } bi = conf->retry_read_aligned_list; if(bi) { - conf->retry_read_aligned = bi->bi_next; + conf->retry_read_aligned_list = bi->bi_next; bi->bi_next = NULL; bi->bi_phys_segments = 1; /* biased count of active stripes */ bi->bi_hw_segments = 0; /* count of processed stripes */ @@ -2669,6 +2669,27 @@ static int raid5_align_endio(struct bio *bi, unsigned int bytes, int error) return 0; } +static int bio_fits_rdev(struct bio *bi) +{ + request_queue_t *q = bdev_get_queue(bi->bi_bdev); + + if ((bi->bi_size>>9) > q->max_sectors) + return 0; + blk_recount_segments(q, bi); + if (bi->bi_phys_segments > q->max_phys_segments || + bi->bi_hw_segments > q->max_hw_segments) + return 0; + + if (q->merge_bvec_fn) + /* it's too hard to apply the merge_bvec_fn at this stage, + * just just give up + */ + return 0; + + return 1; +} + + static int chunk_aligned_read(request_queue_t *q, struct bio * raid_bio) { mddev_t *mddev = q->queuedata; @@ -2715,6 +2736,13 @@ static int chunk_aligned_read(request_queue_t *q, struct bio * raid_bio) align_bi->bi_flags &= ~(1 << BIO_SEG_VALID); align_bi->bi_sector += rdev->data_offset; + if (!bio_fits_rdev(align_bi)) { + /* too big in some way */ + bio_put(align_bi); + rdev_dec_pending(rdev, mddev); + return 0; + } + spin_lock_irq(&conf->device_lock); wait_event_lock_irq(conf->wait_for_stripe, conf->quiesce == 0, @@ -3107,7 +3135,9 @@ static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9); for (; logical_sector < last_sector; - logical_sector += STRIPE_SECTORS, scnt++) { + logical_sector += STRIPE_SECTORS, + sector += STRIPE_SECTORS, + scnt++) { if (scnt < raid_bio->bi_hw_segments) /* already done this stripe */ @@ -3123,7 +3153,13 @@ static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) } set_bit(R5_ReadError, &sh->dev[dd_idx].flags); - add_stripe_bio(sh, raid_bio, dd_idx, 0); + if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) { + release_stripe(sh); + raid_bio->bi_hw_segments = scnt; + conf->retry_read_aligned = raid_bio; + return handled; + } + handle_stripe(sh, NULL); release_stripe(sh); handled++; |