From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422773AbXCGRxs (ORCPT ); Wed, 7 Mar 2007 12:53:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422746AbXCGROO (ORCPT ); Wed, 7 Mar 2007 12:14:14 -0500 Received: from cantor2.suse.de ([195.135.220.15]:42855 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422779AbXCGROD (ORCPT ); Wed, 7 Mar 2007 12:14:03 -0500 Message-Id: <20070307171212.695749800@mini.kroah.org> References: <20070307171035.150802805@mini.kroah.org> User-Agent: quilt/0.45-1 Date: Wed, 07 Mar 2007 09:10:52 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, "Kai" , Andrew Morton Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , torvalds@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jens Axboe , Neil Brown Subject: [patch 017/101] Fix various bugs with aligned reads in RAID5. Content-Disposition: inline; filename=fix-various-bugs-with-aligned-reads-in-raid5.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Neil Brown 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 Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid5.c | 42 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 39 insertions(+), 3 deletions(-) --- linux-2.6.20.1.orig/drivers/md/raid5.c +++ linux-2.6.20.1/drivers/md/raid5.c @@ -2620,7 +2620,7 @@ static struct bio *remove_bio_from_retry } 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 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_qu 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_con 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_con } 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++; --