kernel/linux.git/drivers/md/raid5.c, branch v4.11.5

md: update slab_cache before releasing new stripes when stripes resizing

2017-05-25T13:46:12+00:00

commit 583da48e388f472e8818d9bb60ef6a1d40ee9f9d upstream. When growing raid5 device on machine with small memory, there is chance that mdadm will be killed and the following bug report can be observed. The same bug could also be reproduced in linux-4.10.6. [57600.075774] BUG: unable to handle kernel NULL pointer dereference at (null) [57600.083796] IP: [] _raw_spin_lock+0x7/0x20 [57600.110378] PGD 421cf067 PUD 4442d067 PMD 0 [57600.114678] Oops: 0002 [#1] SMP [57600.180799] CPU: 1 PID: 25990 Comm: mdadm Tainted: P O 4.2.8 #1 [57600.187849] Hardware name: To be filled by O.E.M. To be filled by O.E.M./MAHOBAY, BIOS QV05AR66 03/06/2013 [57600.197490] task: ffff880044e47240 ti: ffff880043070000 task.ti: ffff880043070000 [57600.204963] RIP: 0010:[] [] _raw_spin_lock+0x7/0x20 [57600.213057] RSP: 0018:ffff880043073810 EFLAGS: 00010046 [57600.218359] RAX: 0000000000000000 RBX: 000000000000000c RCX: ffff88011e296dd0 [57600.225486] RDX: 0000000000000001 RSI: ffffe8ffffcb46c0 RDI: 0000000000000000 [57600.232613] RBP: ffff880043073878 R08: ffff88011e5f8170 R09: 0000000000000282 [57600.239739] R10: 0000000000000005 R11: 28f5c28f5c28f5c3 R12: ffff880043073838 [57600.246872] R13: ffffe8ffffcb46c0 R14: 0000000000000000 R15: ffff8800b9706a00 [57600.253999] FS: 00007f576106c700(0000) GS:ffff88011e280000(0000) knlGS:0000000000000000 [57600.262078] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [57600.267817] CR2: 0000000000000000 CR3: 00000000428fe000 CR4: 00000000001406e0 [57600.274942] Stack: [57600.276949] ffffffff8114ee35 ffff880043073868 0000000000000282 000000000000eb3f [57600.284383] ffffffff81119043 ffff880043073838 ffff880043073838 ffff88003e197b98 [57600.291820] ffffe8ffffcb46c0 ffff88003e197360 0000000000000286 ffff880043073968 [57600.299254] Call Trace: [57600.301698] [] ? cache_flusharray+0x35/0xe0 [57600.307523] [] ? __page_cache_release+0x23/0x110 [57600.313779] [] kmem_cache_free+0x63/0xc0 [57600.319344] [] drop_one_stripe+0x62/0x90 [57600.324915] [] raid5_cache_scan+0x8b/0xb0 [57600.330563] [] shrink_slab.part.36+0x19a/0x250 [57600.336650] [] shrink_zone+0x23c/0x250 [57600.342039] [] do_try_to_free_pages+0x153/0x420 [57600.348210] [] try_to_free_pages+0x91/0xa0 [57600.353959] [] __alloc_pages_nodemask+0x4d1/0x8b0 [57600.360303] [] check_reshape+0x62b/0x770 [57600.365866] [] raid5_check_reshape+0x55/0xa0 [57600.371778] [] update_raid_disks+0xc7/0x110 [57600.377604] [] md_ioctl+0xd83/0x1b10 [57600.382827] [] blkdev_ioctl+0x170/0x690 [57600.388307] [] block_ioctl+0x38/0x40 [57600.393525] [] do_vfs_ioctl+0x2b5/0x480 [57600.399010] [] ? vfs_write+0x14b/0x1f0 [57600.404400] [] SyS_ioctl+0x3c/0x70 [57600.409447] [] entry_SYSCALL_64_fastpath+0x12/0x6a [57600.415875] Code: 00 00 00 00 55 48 89 e5 8b 07 85 c0 74 04 31 c0 5d c3 ba 01 00 00 00 f0 0f b1 17 85 c0 75 ef b0 01 5d c3 90 31 c0 ba 01 00 00 00 0f b1 17 85 c0 75 01 c3 55 89 c6 48 89 e5 e8 85 d1 63 ff 5d [57600.435460] RIP [] _raw_spin_lock+0x7/0x20 [57600.441208] RSP [57600.444690] CR2: 0000000000000000 [57600.448000] ---[ end trace cbc6b5cc4bf9831d ]--- The problem is that resize_stripes() releases new stripe_heads before assigning new slab cache to conf->slab_cache. If the shrinker function raid5_cache_scan() gets called after resize_stripes() starting releasing new stripes but right before new slab cache being assigned, it is possible that these new stripe_heads will be freed with the old slab_cache which was already been destoryed and that triggers this bug. Signed-off-by: Dennis Yang Fixes: edbe83ab4c27 ("md/raid5: allow the stripe_cache to grow and shrink.") Reviewed-by: NeilBrown Signed-off-by: Shaohua Li Signed-off-by: Greg Kroah-Hartman

md/r5cache: fix set_syndrome_sources() for data in cache

2017-03-14T16:57:10+00:00

Before this patch, device InJournal will be included in prexor (SYNDROME_SRC_WANT_DRAIN) but not in reconstruct (SYNDROME_SRC_WRITTEN). So it will break parity calculation. With srctype == SYNDROME_SRC_WRITTEN, we need include both dev with non-null ->written and dev with R5_InJournal. This fixes logic in 1e6d690(md/r5cache: caching phase of r5cache) Cc: stable@vger.kernel.org (v4.10+) Signed-off-by: Song Liu Signed-off-by: Shaohua Li

md: move funcs from pers->resize to update_size

2017-03-09T17:02:18+00:00

raid1_resize and raid5_resize should also check the mddev->queue if run underneath dm-raid. And both set_capacity and revalidate_disk are used in pers->resize such as raid1, raid10 and raid5. So move them from personality file to common code. Reviewed-by: NeilBrown Signed-off-by: Guoqing Jiang Signed-off-by: Shaohua Li

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29+00:00

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md

2017-02-24T22:42:19+00:00

Pull md updates from Shaohua Li: "Mainly fixes bugs and improves performance: - Improve scalability for raid1 from Coly - Improve raid5-cache read performance, disk efficiency and IO pattern from Song and me - Fix a race condition of disk hotplug for linear from Coly - A few cleanup patches from Ming and Byungchul - Fix a memory leak from Neil - Fix WRITE SAME IO failure from me - Add doc for raid5-cache from me" * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: (23 commits) md/raid1: fix write behind issues introduced by bio_clone_bioset_partial md/raid1: handle flush request correctly md/linear: shutup lockdep warnning md/raid1: fix a use-after-free bug RAID1: avoid unnecessary spin locks in I/O barrier code RAID1: a new I/O barrier implementation to remove resync window md/raid5: Don't reinvent the wheel but use existing llist API md: fast clone bio in bio_clone_mddev() md: remove unnecessary check on mddev md/raid1: use bio_clone_bioset_partial() in case of write behind md: fail if mddev->bio_set can't be created block: introduce bio_clone_bioset_partial() md: disable WRITE SAME if it fails in underlayer disks md/raid5-cache: exclude reclaiming stripes in reclaim check md/raid5-cache: stripe reclaim only counts valid stripes MD: add doc for raid5-cache Documentation: move MD related doc into a separate dir md: ensure md devices are freed before module is unloaded. md/r5cache: improve journal device efficiency md/r5cache: enable chunk_aligned_read with write back cache ...

Merge branch 'for-4.11/next' into for-4.11/linus-merge

2017-02-17T21:08:19+00:00

Signed-off-by: Jens Axboe

md/raid5: Don't reinvent the wheel but use existing llist API

2017-02-16T22:49:05+00:00

Although llist provides proper APIs, they are not used. Make them used. Signed-off-by: Byungchul Park Signed-off-by: Shaohua Li

md: fast clone bio in bio_clone_mddev()

2017-02-15T19:24:54+00:00

Firstly bio_clone_mddev() is used in raid normal I/O and isn't in resync I/O path. Secondly all the direct access to bvec table in raid happens on resync I/O except for write behind of raid1, in which we still use bio_clone() for allocating new bvec table. So this patch replaces bio_clone() with bio_clone_fast() in bio_clone_mddev(). Also kill bio_clone_mddev() and call bio_clone_fast() directly, as suggested by Christoph Hellwig. Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Shaohua Li

md/raid5-cache: exclude reclaiming stripes in reclaim check

2017-02-13T17:20:05+00:00

stripes which are being reclaimed are still accounted into cached stripes. The reclaim takes time. r5c_do_reclaim isn't aware of the stripes and does unnecessary stripe reclaim. In practice, I saw one stripe is reclaimed one time. This will cause bad IO pattern. Fixing this by excluding the reclaing stripes in the check. Cc: Song Liu Signed-off-by: Shaohua Li

md/r5cache: improve journal device efficiency

2017-02-13T17:17:52+00:00

It is important to be able to flush all stripes in raid5-cache. Therefore, we need reserve some space on the journal device for these flushes. If flush operation includes pending writes to the stripe, we need to reserve (conf->raid_disk + 1) pages per stripe for the flush out. This reduces the efficiency of journal space. If we exclude these pending writes from flush operation, we only need (conf->max_degraded + 1) pages per stripe. With this patch, when log space is critical (R5C_LOG_CRITICAL=1), pending writes will be excluded from stripe flush out. Therefore, we can reduce reserved space for flush out and thus improve journal device efficiency. Signed-off-by: Song Liu Signed-off-by: Shaohua Li