linux/drivers/md/raid1.c, branch v4.3

md/raid1: don't clear bitmap bit when bad-block-list write fails.

2015-10-24T05:24:22Z

When a write fails and a bad-block-list is present, we can update the bad-block-list instead of writing the data. If this succeeds then it is OK clear the relevant bitmap-bit as no further 'sync' of the block is needed. However if writing the bad-block-list fails then we need to treat the write as failed and particularly must not clear the bitmap bit. Otherwise the device can be re-added (after any hardware connection issues are resolved) and because the relevant bit in the bitmap is clear, that block will not be resynced. This leads to data corruption. We already delay the final bio_endio() on the write until the bad-block-list is written so that when the write returns: either that data is safe, the bad-block record is safe, or the fact that the device is faulty is safe. However we *don't* delay the clearing of the bitmap, so the bitmap bit can be recorded as cleared before we know if the bad-block-list was written safely. So: delay that until the write really is safe. i.e. move the call to close_write() until just before calling bio_endio(), and recheck the 'is array degraded' status before making that call. This bug goes back to v3.1 when bad-block-lists were introduced, though it only affects arrays created with mdadm-3.3 or later as only those have bad-block lists. Backports will require at least Commit: 55ce74d4bfe1 ("md/raid1: ensure device failure recorded before write request returns.") as well. I'll send that to 'stable' separately. Note that of the two tests of R1BIO_WriteError that this patch adds, the first is certain to fail and the second is certain to succeed. However doing it this way makes the patch more obviously correct. I will tidy the code up in a future merge window. Reported-and-tested-by: Nate Dailey Cc: Jes Sorensen Fixes: cd5ff9a16f08 ("md/raid1: Handle write errors by updating badblock log.") Signed-off-by: NeilBrown

md/raid1: submit_bio_wait() returns 0 on success

2015-10-20T20:20:15Z

This was introduced with 9e882242c6193ae6f416f2d8d8db0d9126bd996b which changed the return value of submit_bio_wait() to return != 0 on error, but didn't update the caller accordingly. Fixes: 9e882242c6 ("block: Add submit_bio_wait(), remove from md") Cc: stable@vger.kernel.org (v3.10) Reported-by: Bill Kuzeja Signed-off-by: Jes Sorensen Signed-off-by: NeilBrown

crash in md-raid1 and md-raid10 due to incorrect list manipulation

2015-10-08T21:33:46Z

The commit 55ce74d4bfe1b9444436264c637f39a152d1e5ac (md/raid1: ensure device failure recorded before write request returns) is causing crash in the LVM2 testsuite test shell/lvchange-raid.sh. For me the crash is 100% reproducible. The reason for the crash is that the newly added code in raid1d moves the list from conf->bio_end_io_list to tmp, then tests if tmp is non-empty and then incorrectly pops the bio from conf->bio_end_io_list (which is empty because the list was alrady moved). Raid-10 has a similar bug. Kernel Fault: Code=15 regs=000000006ccb8640 (Addr=0000000100000000) CPU: 3 PID: 1930 Comm: mdX_raid1 Not tainted 4.2.0-rc5-bisect+ #35 task: 000000006cc1f258 ti: 000000006ccb8000 task.ti: 000000006ccb8000 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001001111111000001111 Not tainted r00-03 000000ff0804fe0f 000000001059d000 000000001059f818 000000007f16be38 r04-07 000000001059d000 000000007f16be08 0000000000200200 0000000000000001 r08-11 000000006ccb8260 000000007b7934d0 0000000000000001 0000000000000000 r12-15 000000004056f320 0000000000000000 0000000000013dd0 0000000000000000 r16-19 00000000f0d00ae0 0000000000000000 0000000000000000 0000000000000001 r20-23 000000000800000f 0000000042200390 0000000000000000 0000000000000000 r24-27 0000000000000001 000000000800000f 000000007f16be08 000000001059d000 r28-31 0000000100000000 000000006ccb8560 000000006ccb8640 0000000000000000 sr00-03 0000000000249800 0000000000000000 0000000000000000 0000000000249800 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 000000001059f61c 000000001059f620 IIR: 0f8010c6 ISR: 0000000000000000 IOR: 0000000100000000 CPU: 3 CR30: 000000006ccb8000 CR31: 0000000000000000 ORIG_R28: 000000001059d000 IAOQ[0]: call_bio_endio+0x34/0x1a8 [raid1] IAOQ[1]: call_bio_endio+0x38/0x1a8 [raid1] RP(r2): raid_end_bio_io+0x88/0x168 [raid1] Backtrace: [<000000001059f818>] raid_end_bio_io+0x88/0x168 [raid1] [<00000000105a4f64>] raid1d+0x144/0x1640 [raid1] [<000000004017fd5c>] kthread+0x144/0x160 Signed-off-by: Mikulas Patocka Fixes: 55ce74d4bfe1 ("md/raid1: ensure device failure recorded before write request returns.") Fixes: 95af587e95aa ("md/raid10: ensure device failure recorded before write request returns.") Signed-off-by: NeilBrown

md/raid1: Avoid raid1 resync getting stuck

2015-10-02T07:23:44Z

close_sync() needs to set conf->next_resync to a large, but safe value below MaxSector and use it to determine whether or not to set start_next_window in wait_barrier() Solution suggested by Neil Brown. Reported-by: Nate Dailey Tested-by: Xiao Ni Signed-off-by: Jes Sorensen Signed-off-by: NeilBrown

md: drop null test before destroy functions

2015-10-02T07:23:44Z

Remove unneeded NULL test. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // @@ expression x; @@ -if (x != NULL) \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x); // Signed-off-by: Julia Lawall Signed-off-by: NeilBrown

Merge linux-block/for-4.3/core into md/for-linux

2015-09-05T09:08:32Z

There were a few conflicts that are fairly easy to resolve. Signed-off-by: NeilBrown

Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block

2015-09-02T20:10:25Z

Pull core block updates from Jens Axboe: "This first core part of the block IO changes contains: - Cleanup of the bio IO error signaling from Christoph. We used to rely on the uptodate bit and passing around of an error, now we store the error in the bio itself. - Improvement of the above from myself, by shrinking the bio size down again to fit in two cachelines on x86-64. - Revert of the max_hw_sectors cap removal from a revision again, from Jeff Moyer. This caused performance regressions in various tests. Reinstate the limit, bump it to a more reasonable size instead. - Make /sys/block//queue/discard_max_bytes writeable, by me. Most devices have huge trim limits, which can cause nasty latencies when deleting files. Enable the admin to configure the size down. We will look into having a more sane default instead of UINT_MAX sectors. - Improvement of the SGP gaps logic from Keith Busch. - Enable the block core to handle arbitrarily sized bios, which enables a nice simplification of bio_add_page() (which is an IO hot path). From Kent. - Improvements to the partition io stats accounting, making it faster. From Ming Lei. - Also from Ming Lei, a basic fixup for overflow of the sysfs pending file in blk-mq, as well as a fix for a blk-mq timeout race condition. - Ming Lin has been carrying Kents above mentioned patches forward for a while, and testing them. Ming also did a few fixes around that. - Sasha Levin found and fixed a use-after-free problem introduced by the bio->bi_error changes from Christoph. - Small blk cgroup cleanup from Viresh Kumar" * 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits) blk: Fix bio_io_vec index when checking bvec gaps block: Replace SG_GAPS with new queue limits mask block: bump BLK_DEF_MAX_SECTORS to 2560 Revert "block: remove artifical max_hw_sectors cap" blk-mq: fix race between timeout and freeing request blk-mq: fix buffer overflow when reading sysfs file of 'pending' Documentation: update notes in biovecs about arbitrarily sized bios block: remove bio_get_nr_vecs() fs: use helper bio_add_page() instead of open coding on bi_io_vec block: kill merge_bvec_fn() completely md/raid5: get rid of bio_fits_rdev() md/raid5: split bio for chunk_aligned_read block: remove split code in blkdev_issue_{discard,write_same} btrfs: remove bio splitting and merge_bvec_fn() calls bcache: remove driver private bio splitting code block: simplify bio_add_page() block: make generic_make_request handle arbitrarily sized bios blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL) block: don't access bio->bi_error after bio_put() block: shrink struct bio down to 2 cache lines again ...

md/raid1: ensure device failure recorded before write request returns.

2015-08-31T17:43:23Z

When a write to one of the legs of a RAID1 fails, the failure is recorded in the metadata of the other leg(s) so that after a restart the data on the failed drive wont be trusted even if that drive seems to be working again (maybe a cable was unplugged). Similarly when we record a bad-block in response to a write failure, we must not let the write complete until the bad-block update is safe. Currently there is no interlock between the write request completing and the metadata update. So it is possible that the write will complete, the app will confirm success in some way, and then the machine will crash before the metadata update completes. This is an extremely small hole for a racy to fit in, but it is theoretically possible and so should be closed. So: - set MD_CHANGE_PENDING when requesting a metadata update for a failed device, so we can know with certainty when it completes - queue requests that experienced an error on a new queue which is only processed after the metadata update completes - call raid_end_bio_io() on bios in that queue when the time comes. Signed-off-by: NeilBrown

md: close some races between setting and checking sync_action.

2015-08-31T17:30:40Z

When checking sync_action in a script, we want to be sure it is as accurate as possible. As resync/reshape etc doesn't always start immediately (a separate thread is scheduled to do it), it is best if 'action_show' checks if MD_RECOVER_NEEDED is set (which it does) and in that case reports what is likely to start soon (which it only sometimes does). So: - report 'reshape' if reshape_position suggests one might start. - set MD_RECOVERY_RECOVER in raid1_reshape(), because that is very likely to happen next. Signed-off-by: NeilBrown

block: kill merge_bvec_fn() completely

2015-08-13T18:31:57Z

As generic_make_request() is now able to handle arbitrarily sized bios, it's no longer necessary for each individual block driver to define its own ->merge_bvec_fn() callback. Remove every invocation completely. Cc: Jens Axboe Cc: Lars Ellenberg Cc: drbd-user@lists.linbit.com Cc: Jiri Kosina Cc: Yehuda Sadeh Cc: Sage Weil Cc: Alex Elder Cc: ceph-devel@vger.kernel.org Cc: Alasdair Kergon Cc: Mike Snitzer Cc: dm-devel@redhat.com Cc: Neil Brown Cc: linux-raid@vger.kernel.org Cc: Christoph Hellwig Cc: "Martin K. Petersen" Acked-by: NeilBrown (for the 'md' bits) Acked-by: Mike Snitzer Signed-off-by: Kent Overstreet [dpark: also remove ->merge_bvec_fn() in dm-thin as well as dm-era-target, and resolve merge conflicts] Signed-off-by: Dongsu Park Signed-off-by: Ming Lin Signed-off-by: Jens Axboe