From: Mikulas Patocka <mpatocka@redhat.com> Date: Thu, 23 Apr 2009 01:05:02 -0400 Subject: [md] dm-raid1/mpath: partially completed request crash Message-id: Pine.LNX.4.64.0904230101270.12945@hs20-bc2-1.build.redhat.com O-Subject: [PATCH 1/2 RHEL5.4] bz496101 crash in dm-raid1/dm-mpath with partially completed request Bugzilla: 496101 RH-Acked-by: Jonathan Brassow <jbrassow@redhat.com> This fixes a crash in dm-raid or dm-multipath when disk signals partial completion. Testing: did some basic filesystem operations on raid1, checked that the data are preserved. I didn't test possibility of partial read requests but some people at RH test labs did and found that the patch fixes the problem (see bz472796). Mikulas Commit: a920f6b3accc77d9dddbc98a7426be23ee479625 From: Mikulas Patocka <mpatocka@redhat.com> Date: Thu, 2 Apr 2009 18:55:23 +0000 (+0100) Subject: dm: preserve bi_io_vec when resubmitting bios X-Git-Tag: v2.6.30-rc1~230^2~35 X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=a920f6b3accc77d9dddbc98a7426be23ee479625;hp=833bb3046b6cb320e775ea2160ddca87d53260d5 dm: preserve bi_io_vec when resubmitting bios Device mapper saves and restores various fields in the bio, but it doesn't save bi_io_vec. If the device driver modifies this after a partially successful request, dm-raid1 and dm-multipath may attempt to resubmit a bio that has bi_size inconsistent with the size of vector. To make requests resubmittable in dm-raid1 and dm-multipath, we must save and restore the bio vector as well. To reduce the memory overhead involved in this, we do not save the pages in a vector and use a 16-bit field size if the page size is less than 65536. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> diff --git a/drivers/md/dm-bio-record.h b/drivers/md/dm-bio-record.h index d3ec217..3a8cfa2 100644 --- a/drivers/md/dm-bio-record.h +++ b/drivers/md/dm-bio-record.h @@ -16,30 +16,56 @@ * functions in this file help the target record and restore the * original bio state. */ + +struct dm_bio_vec_details { +#if PAGE_SIZE < 65536 + __u16 bv_len; + __u16 bv_offset; +#else + unsigned bv_len; + unsigned bv_offset; +#endif +}; + struct dm_bio_details { sector_t bi_sector; struct block_device *bi_bdev; unsigned int bi_size; unsigned short bi_idx; unsigned long bi_flags; + struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES]; }; static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio) { + unsigned i; + bd->bi_sector = bio->bi_sector; bd->bi_bdev = bio->bi_bdev; bd->bi_size = bio->bi_size; bd->bi_idx = bio->bi_idx; bd->bi_flags = bio->bi_flags; + + for (i = 0; i < bio->bi_vcnt; i++) { + bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len; + bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset; + } } static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio) { + unsigned i; + bio->bi_sector = bd->bi_sector; bio->bi_bdev = bd->bi_bdev; bio->bi_size = bd->bi_size; bio->bi_idx = bd->bi_idx; bio->bi_flags = bd->bi_flags; + + for (i = 0; i < bio->bi_vcnt; i++) { + bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len; + bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset; + } } #endif