linux-stable/drivers/md
Darrick J. Wong 37527b8692 dm io: reject unsupported DISCARD requests with EOPNOTSUPP
I created a dm-raid1 device backed by a device that supports DISCARD
and another device that does NOT support DISCARD with the following
dm configuration:

 #  echo '0 2048 mirror core 1 512 2 /dev/sda 0 /dev/sdb 0' | dmsetup create moo
 # lsblk -D
 NAME         DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
 sda                 0        4K       1G         0
 `-moo (dm-0)        0        4K       1G         0
 sdb                 0        0B       0B         0
 `-moo (dm-0)        0        4K       1G         0

Notice that the mirror device /dev/mapper/moo advertises DISCARD
support even though one of the mirror halves doesn't.

If I issue a DISCARD request (via fstrim, mount -o discard, or ioctl
BLKDISCARD) through the mirror, kmirrord gets stuck in an infinite
loop in do_region() when it tries to issue a DISCARD request to sdb.
The problem is that when we call do_region() against sdb, num_sectors
is set to zero because q->limits.max_discard_sectors is zero.
Therefore, "remaining" never decreases and the loop never terminates.

To fix this: before entering the loop, check for the combination of
REQ_DISCARD and no discard and return -EOPNOTSUPP to avoid hanging up
the mirror device.

This bug was found by the unfortunate coincidence of pvmove and a
discard operation in the RHEL 6.5 kernel; upstream is also affected.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-13 19:51:09 -05:00
..
bcache md/bcache: use generic io stats accounting functions to simplify io stat accounting 2014-11-24 08:05:12 -07:00
persistent-data dm space map disk: fix sm_disk_count_is_more_than_one() 2015-02-13 19:32:58 -05:00
bitmap.c md: remove mddev_lock() from md_attr_show() 2015-02-06 09:32:55 +11:00
bitmap.h
dm-bio-prison.c dm bio prison: introduce support for locking ranges of blocks 2014-11-10 15:25:30 -05:00
dm-bio-prison.h dm bio prison: introduce support for locking ranges of blocks 2014-11-10 15:25:30 -05:00
dm-bio-record.h
dm-bufio.c dm bufio: fix time comparison to use time_after_eq() 2015-02-09 13:06:48 -05:00
dm-bufio.h dm snapshot: use dm-bufio prefetch 2014-01-14 23:23:03 -05:00
dm-builtin.c dm sysfs: fix a module unload race 2014-01-14 23:23:04 -05:00
dm-cache-block-types.h dm cache: revert "remove remainder of distinct discard block size" 2014-11-10 15:25:30 -05:00
dm-cache-metadata.c dm cache: fix missing ERR_PTR returns and handling 2015-01-28 09:59:20 -05:00
dm-cache-metadata.h dm cache: revert "remove remainder of distinct discard block size" 2014-11-10 15:25:30 -05:00
dm-cache-policy-cleaner.c
dm-cache-policy-internal.h
dm-cache-policy-mq.c dm cache policy mq: simplify ability to promote sequential IO to the cache 2014-11-10 15:25:30 -05:00
dm-cache-policy.c dm cache: add policy name to status output 2014-01-16 13:44:11 -05:00
dm-cache-policy.h dm cache: add policy name to status output 2014-01-16 13:44:11 -05:00
dm-cache-target.c - Most significant change this cycle is request-based DM now supports 2015-02-12 16:36:31 -08:00
dm-crypt.c - Significant DM thin-provisioning performance improvements to meet 2014-12-08 21:10:03 -08:00
dm-delay.c Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
dm-era-target.c dm era: check for a non-NULL metadata object before closing it 2014-06-03 13:44:08 -04:00
dm-exception-store.c
dm-exception-store.h
dm-flakey.c
dm-io.c dm io: reject unsupported DISCARD requests with EOPNOTSUPP 2015-02-13 19:51:09 -05:00
dm-ioctl.c dm ioctl: fix stale comment above dm_get_inactive_table() 2015-02-09 13:06:48 -05:00
dm-kcopyd.c
dm-linear.c
dm-log-userspace-base.c dm: use time_in_range() and time_after() 2015-02-09 13:06:48 -05:00
dm-log-userspace-transfer.c dm log userspace: fix memory leak in dm_ulog_tfr_init failure path 2014-10-05 20:03:38 -04:00
dm-log-userspace-transfer.h
dm-log.c
dm-mpath.c dm mpath: simplify failure path of dm_multipath_init() 2015-02-09 13:06:49 -05:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c
dm-raid.c - Most significant change this cycle is request-based DM now supports 2015-02-12 16:36:31 -08:00
dm-raid1.c dm mirror: do not degrade the mirror on discard error 2015-02-13 19:50:46 -05:00
dm-region-hash.c
dm-round-robin.c
dm-service-time.c
dm-snap-persistent.c dm snapshot: remove unnecessary NULL checks before vfree() calls 2015-02-09 13:06:49 -05:00
dm-snap-transient.c
dm-snap.c sched: Remove proliferation of wait_on_bit() action functions 2014-07-16 15:10:39 +02:00
dm-stats.c - Significant DM thin-provisioning performance improvements to meet 2014-12-08 21:10:03 -08:00
dm-stats.h
dm-stripe.c dm stripe: fix potential for leak in stripe_ctr error path 2014-10-10 22:05:18 -04:00
dm-switch.c dm switch: efficiently support repetitive patterns 2014-08-01 12:30:37 -04:00
dm-sysfs.c dm sysfs: fix a module unload race 2014-01-14 23:23:04 -05:00
dm-table.c dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queues 2015-02-11 10:25:46 -05:00
dm-target.c dm: allocate requests in target when stacking on blk-mq devices 2015-02-09 13:06:47 -05:00
dm-thin-metadata.c dm thin metadata: remove unused dm_pool_get_data_block_size() 2015-02-09 13:06:49 -05:00
dm-thin-metadata.h dm thin metadata: remove unused dm_pool_get_data_block_size() 2015-02-09 13:06:49 -05:00
dm-thin.c - Most significant change this cycle is request-based DM now supports 2015-02-12 16:36:31 -08:00
dm-uevent.c
dm-uevent.h
dm-verity.c dm verity: fix biovecs hash calculation regression 2014-04-15 12:19:24 -04:00
dm-zero.c dm crypt, dm zero: update author name following legal name change 2014-07-10 16:44:14 -04:00
dm.c - Most significant change this cycle is request-based DM now supports 2015-02-12 16:36:31 -08:00
dm.h dm table: train hybrid target type detection to select blk-mq if appropriate 2015-02-09 13:06:47 -05:00
faulty.c md: rename ->stop to ->free 2015-02-04 08:35:52 +11:00
Kconfig - Most significant change this cycle is request-based DM now supports 2015-02-12 16:36:31 -08:00
linear.c md: rename ->stop to ->free 2015-02-04 08:35:52 +11:00
linear.h
Makefile dm: add era target 2014-03-27 16:56:23 -04:00
md.c md: make reconfig_mutex optional for writes to md sysfs files. 2015-02-06 09:32:56 +11:00
md.h md: wakeup thread upon rdev_dec_pending() 2015-02-06 09:32:57 +11:00
multipath.c md: rename ->stop to ->free 2015-02-04 08:35:52 +11:00
multipath.h
raid0.c md: rename ->stop to ->free 2015-02-04 08:35:52 +11:00
raid0.h
raid1.c md: rename ->stop to ->free 2015-02-04 08:35:52 +11:00
raid1.h md: make ->congested robust against personality changes. 2015-02-04 08:35:52 +11:00
raid5.c md: make reconfig_mutex optional for writes to md sysfs files. 2015-02-06 09:32:56 +11:00
raid5.h md: make ->congested robust against personality changes. 2015-02-04 08:35:52 +11:00
raid10.c md/raid10: fix conversion from RAID0 to RAID10 2015-02-12 14:09:57 +11:00
raid10.h md: make ->congested robust against personality changes. 2015-02-04 08:35:52 +11:00