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* Merge branch 'WIP.sched-core-for-linus' of ↵Linus Torvalds2017-03-0314-0/+19
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull sched.h split-up from Ingo Molnar: "The point of these changes is to significantly reduce the <linux/sched.h> header footprint, to speed up the kernel build and to have a cleaner header structure. After these changes the new <linux/sched.h>'s typical preprocessed size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K lines), which is around 40% faster to build on typical configs. Not much changed from the last version (-v2) posted three weeks ago: I eliminated quirks, backmerged fixes plus I rebased it to an upstream SHA1 from yesterday that includes most changes queued up in -next plus all sched.h changes that were pending from Andrew. I've re-tested the series both on x86 and on cross-arch defconfigs, and did a bisectability test at a number of random points. I tried to test as many build configurations as possible, but some build breakage is probably still left - but it should be mostly limited to architectures that have no cross-compiler binaries available on kernel.org, and non-default configurations" * 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits) sched/headers: Clean up <linux/sched.h> sched/headers: Remove #ifdefs from <linux/sched.h> sched/headers: Remove the <linux/topology.h> include from <linux/sched.h> sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h> sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h> sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h> sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h> sched/headers: Remove <linux/sched.h> from <linux/sched/init.h> sched/core: Remove unused prefetch_stack() sched/headers: Remove <linux/rculist.h> from <linux/sched.h> sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h> sched/headers: Remove <linux/signal.h> from <linux/sched.h> sched/headers: Remove <linux/rwsem.h> from <linux/sched.h> sched/headers: Remove the runqueue_is_locked() prototype sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h> sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h> sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h> sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h> ...
| * sched/headers: Prepare to move the get_task_struct()/put_task_struct() and ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | related APIs from <linux/sched.h> to <linux/sched/task.h> But first update usage sites with the new header dependency. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/headers: Prepare to use <linux/rcuupdate.h> instead of ↵Ingo Molnar2017-03-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/rculist.h> in <linux/sched.h> We don't actually need the full rculist.h header in sched.h anymore, we will be able to include the smaller rcupdate.h header instead. But first update code that relied on the implicit header inclusion. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> 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 <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/headers: Prepare to move the memalloc_noio_*() APIs to <linux/sched/mm.h>Ingo Molnar2017-03-022-0/+2
| | | | | | | | | | | | | | | | | | | | | | Update the .c files that depend on these APIs. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-023-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> 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 <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-026-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched/clock.h> We are going to split <linux/sched/clock.h> out of <linux/sched.h>, which will have to be picked up from other headers and .c files. Create a trivial placeholder <linux/sched/clock.h> file that just maps to <linux/sched.h> 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 <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge tag 'dm-4.11-fixes' of ↵Linus Torvalds2017-03-021-4/+16
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper fixes from Mike Snitzer: - a dm-raid stable@ fix for possible corruption when triggering a raid reshape via lvm2; and an additional small patch ontop to bump version of the dm-raid target outside of the stable@ fix - a dm-raid fix for a 'dm-4.11-changes' regression introduced by a commit that was meant to only cleanup confusing branching. * tag 'dm-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm raid: bump the target version dm raid: fix data corruption on reshape request dm raid: fix raid "check" regression due to improper cleanup in raid_message()
| * | dm raid: bump the target versionMike Snitzer2017-02-281-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This version bump reflects that the reshape corruption fix (commit 92a39f6cc "dm raid: fix data corruption on reshape request") is present. Done as a separate fix because the above referenced commit is marked for stable and target version bumps in a stable@ fix are a recipe for the fix to never get backported to stable@ kernels (because of target version number conflicts). Also, move RESUME_STAY_FROZEN_FLAGS up with the reset the the _FLAGS definitions now that we don't need to worry about stable@ conflicts as a result of missing context. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm raid: fix data corruption on reshape requestHeinz Mauelshagen2017-02-281-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The lvm2 sequence to manage dm-raid constructor flags that trigger a rebuild or a reshape is defined as: 1) load table with flags (e.g. rebuild/delta_disks/data_offset) 2) clear out the flags in lvm2 metadata 3) store the lvm2 metadata, reload the table to reset the flags previously established during the initial load (1) -- in order to prevent repeatedly requesting a rebuild or a reshape on activation Currently, loading an inactive table with rebuild/reshape flags specified will cause dm-raid to rebuild/reshape on resume and thus start updating the raid metadata (about the progress). When the second table reload, to reset the flags, occurs the constructor accesses the volatile progress state kept in the raid superblocks. Because the active mapping is still processing the rebuild/reshape, that position will be stale by the time the device is resumed. In the reshape case, this causes data corruption by processing already reshaped stripes again. In the rebuild case, it does _not_ cause data corruption but instead involves superfluous rebuilds. Fix by keeping the raid set frozen during the first resume and then allow the rebuild/reshape during the second resume. Fixes: 9dbd1aa3a ("dm raid: add reshaping support to the target") Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 4.8+
| * | dm raid: fix raid "check" regression due to improper cleanup in raid_message()Mike Snitzer2017-02-281-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While cleaning up awkward branching in raid_message() a raid set "check" regression was introduced because "check" needs both MD_RECOVERY_SYNC and MD_RECOVERY_REQUESTED flags set. Fix this regression by explicitly setting both flags for the "check" case (like is also done for the "repair" case, but redundant set_bit()s are perfectly fine because it adds clarity to what is needed in response to both messages -- in addition this isn't fast path code). Fixes: 105db59912 ("dm raid: cleanup awkward branching in raid_message() option processing") Reported-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* | | KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()David Howells2017-03-021-1/+1
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rcu_dereference_key() and user_key_payload() are currently being used in two different, incompatible ways: (1) As a wrapper to rcu_dereference() - when only the RCU read lock used to protect the key. (2) As a wrapper to rcu_dereference_protected() - when the key semaphor is used to protect the key and the may be being modified. Fix this by splitting both of the key wrappers to produce: (1) RCU accessors for keys when caller has the key semaphore locked: dereference_key_locked() user_key_payload_locked() (2) RCU accessors for keys when caller holds the RCU read lock: dereference_key_rcu() user_key_payload_rcu() This should fix following warning in the NFS idmapper =============================== [ INFO: suspicious RCU usage. ] 4.10.0 #1 Tainted: G W ------------------------------- ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 1 lock held by mount.nfs/5987: #0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4] stack backtrace: CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1 Call Trace: dump_stack+0xe8/0x154 (unreliable) lockdep_rcu_suspicious+0x140/0x190 nfs_idmap_get_key+0x380/0x420 [nfsv4] nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4] decode_getfattr_attrs+0xfac/0x16b0 [nfsv4] decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4] nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4] rpcauth_unwrap_resp+0xe8/0x140 [sunrpc] call_decode+0x29c/0x910 [sunrpc] __rpc_execute+0x140/0x8f0 [sunrpc] rpc_run_task+0x170/0x200 [sunrpc] nfs4_call_sync_sequence+0x68/0xa0 [nfsv4] _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4] nfs4_lookup_root+0xe0/0x350 [nfsv4] nfs4_lookup_root_sec+0x70/0xa0 [nfsv4] nfs4_find_root_sec+0xc4/0x100 [nfsv4] nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4] nfs4_get_rootfh+0x6c/0x190 [nfsv4] nfs4_server_common_setup+0xc4/0x260 [nfsv4] nfs4_create_server+0x278/0x3c0 [nfsv4] nfs4_remote_mount+0x50/0xb0 [nfsv4] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 nfs_do_root_mount+0xb0/0x140 [nfsv4] nfs4_try_mount+0x60/0x100 [nfsv4] nfs_fs_mount+0x5ec/0xda0 [nfs] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 do_mount+0x254/0xf70 SyS_mount+0x94/0x100 system_call+0x38/0xe0 Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds2017-02-2413-335/+768
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ...
| * | md/raid1: fix write behind issues introduced by bio_clone_bioset_partialShaohua Li2017-02-231-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are two issues, introduced by commit 8e58e32(md/raid1: use bio_clone_bioset_partial() in case of write behind): - bio_clone_bioset_partial() uses bytes instead of sectors as parameters - in writebehind mode, we return bio if all !writemostly disk bios finish, which could happen before writemostly disk bios run. So all writemostly disk bios should have their bvec. Here we just make sure all bios are cloned instead of fast cloned. Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/raid1: handle flush request correctlyShaohua Li2017-02-231-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I got a warning triggered in align_to_barrier_unit_end. It's a flush request so sectors == 0. The flush request happens to work well without the new barrier patch, but we'd better handle it explictly. Cc: NeilBrown <neilb@suse.com> Acked-by: Coly Li <colyli@suse.de> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/linear: shutup lockdep warnningShaohua Li2017-02-231-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | Commit 03a9e24(md linear: fix a race between linear_add() and linear_congested()) introduces the warnning. Acked-by: Coly Li <colyli@suse.de> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/raid1: fix a use-after-free bugShaohua Li2017-02-201-1/+2
| | | | | | | | | | | | | | | | | | | | | Commit fd76863 (RAID1: a new I/O barrier implementation to remove resync window) introduces a user-after-free bug. Signed-off-by: Shaohua Li <shli@fb.com>
| * | RAID1: avoid unnecessary spin locks in I/O barrier codecolyli@suse.de2017-02-202-66/+130
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I run a parallel reading performan testing on a md raid1 device with two NVMe SSDs, I observe very bad throughput in supprise: by fio with 64KB block size, 40 seq read I/O jobs, 128 iodepth, overall throughput is only 2.7GB/s, this is around 50% of the idea performance number. The perf reports locking contention happens at allow_barrier() and wait_barrier() code, - 41.41% fio [kernel.kallsyms] [k] _raw_spin_lock_irqsave - _raw_spin_lock_irqsave + 89.92% allow_barrier + 9.34% __wake_up - 37.30% fio [kernel.kallsyms] [k] _raw_spin_lock_irq - _raw_spin_lock_irq - 100.00% wait_barrier The reason is, in these I/O barrier related functions, - raise_barrier() - lower_barrier() - wait_barrier() - allow_barrier() They always hold conf->resync_lock firstly, even there are only regular reading I/Os and no resync I/O at all. This is a huge performance penalty. The solution is a lockless-like algorithm in I/O barrier code, and only holding conf->resync_lock when it has to. The original idea is from Hannes Reinecke, and Neil Brown provides comments to improve it. I continue to work on it, and make the patch into current form. In the new simpler raid1 I/O barrier implementation, there are two wait barrier functions, - wait_barrier() Which calls _wait_barrier(), is used for regular write I/O. If there is resync I/O happening on the same I/O barrier bucket, or the whole array is frozen, task will wait until no barrier on same barrier bucket, or the whold array is unfreezed. - wait_read_barrier() Since regular read I/O won't interfere with resync I/O (read_balance() will make sure only uptodate data will be read out), it is unnecessary to wait for barrier in regular read I/Os, waiting in only necessary when the whole array is frozen. The operations on conf->nr_pending[idx], conf->nr_waiting[idx], conf-> barrier[idx] are very carefully designed in raise_barrier(), lower_barrier(), _wait_barrier() and wait_read_barrier(), in order to avoid unnecessary spin locks in these functions. Once conf-> nr_pengding[idx] is increased, a resync I/O with same barrier bucket index has to wait in raise_barrier(). Then in _wait_barrier() if no barrier raised in same barrier bucket index and array is not frozen, the regular I/O doesn't need to hold conf->resync_lock, it can just increase conf->nr_pending[idx], and return to its caller. wait_read_barrier() is very similar to _wait_barrier(), the only difference is it only waits when array is frozen. For heavy parallel reading I/Os, the lockless I/O barrier code almostly gets rid of all spin lock cost. This patch significantly improves raid1 reading peroformance. From my testing, a raid1 device built by two NVMe SSD, runs fio with 64KB blocksize, 40 seq read I/O jobs, 128 iodepth, overall throughput increases from 2.7GB/s to 4.6GB/s (+70%). Changelog V4: - Change conf->nr_queued[] to atomic_t. - Define BARRIER_BUCKETS_NR_BITS by (PAGE_SHIFT - ilog2(sizeof(atomic_t))) V3: - Add smp_mb__after_atomic() as Shaohua and Neil suggested. - Change conf->nr_queued[] from atomic_t to int. - Change conf->array_frozen from atomic_t back to int, and use READ_ONCE(conf->array_frozen) to check value of conf->array_frozen in _wait_barrier() and wait_read_barrier(). - In _wait_barrier() and wait_read_barrier(), add a call to wake_up(&conf->wait_barrier) after atomic_dec(&conf->nr_pending[idx]), to fix a deadlock between _wait_barrier()/wait_read_barrier and freeze_array(). V2: - Remove a spin_lock/unlock pair in raid1d(). - Add more code comments to explain why there is no racy when checking two atomic_t variables at same time. V1: - Original RFC patch for comments. Signed-off-by: Coly Li <colyli@suse.de> Cc: Shaohua Li <shli@fb.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Guoqing Jiang <gqjiang@suse.com> Reviewed-by: Neil Brown <neilb@suse.de> Signed-off-by: Shaohua Li <shli@fb.com>
| * | RAID1: a new I/O barrier implementation to remove resync windowcolyli@suse.de2017-02-202-236/+294
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'Commit 79ef3a8aa1cb ("raid1: Rewrite the implementation of iobarrier.")' introduces a sliding resync window for raid1 I/O barrier, this idea limits I/O barriers to happen only inside a slidingresync window, for regular I/Os out of this resync window they don't need to wait for barrier any more. On large raid1 device, it helps a lot to improve parallel writing I/O throughput when there are background resync I/Os performing at same time. The idea of sliding resync widow is awesome, but code complexity is a challenge. Sliding resync window requires several variables to work collectively, this is complexed and very hard to make it work correctly. Just grep "Fixes: 79ef3a8aa1" in kernel git log, there are 8 more patches to fix the original resync window patch. This is not the end, any further related modification may easily introduce more regreassion. Therefore I decide to implement a much simpler raid1 I/O barrier, by removing resync window code, I believe life will be much easier. The brief idea of the simpler barrier is, - Do not maintain a global unique resync window - Use multiple hash buckets to reduce I/O barrier conflicts, regular I/O only has to wait for a resync I/O when both them have same barrier bucket index, vice versa. - I/O barrier can be reduced to an acceptable number if there are enough barrier buckets Here I explain how the barrier buckets are designed, - BARRIER_UNIT_SECTOR_SIZE The whole LBA address space of a raid1 device is divided into multiple barrier units, by the size of BARRIER_UNIT_SECTOR_SIZE. Bio requests won't go across border of barrier unit size, that means maximum bio size is BARRIER_UNIT_SECTOR_SIZE<<9 (64MB) in bytes. For random I/O 64MB is large enough for both read and write requests, for sequential I/O considering underlying block layer may merge them into larger requests, 64MB is still good enough. Neil also points out that for resync operation, "we want the resync to move from region to region fairly quickly so that the slowness caused by having to synchronize with the resync is averaged out over a fairly small time frame". For full speed resync, 64MB should take less then 1 second. When resync is competing with other I/O, it could take up a few minutes. Therefore 64MB size is fairly good range for resync. - BARRIER_BUCKETS_NR There are BARRIER_BUCKETS_NR buckets in total, which is defined by, #define BARRIER_BUCKETS_NR_BITS (PAGE_SHIFT - 2) #define BARRIER_BUCKETS_NR (1<<BARRIER_BUCKETS_NR_BITS) this patch makes the bellowed members of struct r1conf from integer to array of integers, - int nr_pending; - int nr_waiting; - int nr_queued; - int barrier; + int *nr_pending; + int *nr_waiting; + int *nr_queued; + int *barrier; number of the array elements is defined as BARRIER_BUCKETS_NR. For 4KB kernel space page size, (PAGE_SHIFT - 2) indecates there are 1024 I/O barrier buckets, and each array of integers occupies single memory page. 1024 means for a request which is smaller than the I/O barrier unit size has ~0.1% chance to wait for resync to pause, which is quite a small enough fraction. Also requesting single memory page is more friendly to kernel page allocator than larger memory size. - I/O barrier bucket is indexed by bio start sector If multiple I/O requests hit different I/O barrier units, they only need to compete I/O barrier with other I/Os which hit the same I/O barrier bucket index with each other. The index of a barrier bucket which a bio should look for is calculated by sector_to_idx() which is defined in raid1.h as an inline function, static inline int sector_to_idx(sector_t sector) { return hash_long(sector >> BARRIER_UNIT_SECTOR_BITS, BARRIER_BUCKETS_NR_BITS); } Here sector_nr is the start sector number of a bio. - Single bio won't go across boundary of a I/O barrier unit If a request goes across boundary of barrier unit, it will be split. A bio may be split in raid1_make_request() or raid1_sync_request(), if sectors returned by align_to_barrier_unit_end() is smaller than original bio size. Comparing to single sliding resync window, - Currently resync I/O grows linearly, therefore regular and resync I/O will conflict within a single barrier units. So the I/O behavior is similar to single sliding resync window. - But a barrier unit bucket is shared by all barrier units with identical barrier uinit index, the probability of conflict might be higher than single sliding resync window, in condition that writing I/Os always hit barrier units which have identical barrier bucket indexs with the resync I/Os. This is a very rare condition in real I/O work loads, I cannot imagine how it could happen in practice. - Therefore we can achieve a good enough low conflict rate with much simpler barrier algorithm and implementation. There are two changes should be noticed, - In raid1d(), I change the code to decrease conf->nr_pending[idx] into single loop, it looks like this, spin_lock_irqsave(&conf->device_lock, flags); conf->nr_queued[idx]--; spin_unlock_irqrestore(&conf->device_lock, flags); This change generates more spin lock operations, but in next patch of this patch set, it will be replaced by a single line code, atomic_dec(&conf->nr_queueud[idx]); So we don't need to worry about spin lock cost here. - Mainline raid1 code split original raid1_make_request() into raid1_read_request() and raid1_write_request(). If the original bio goes across an I/O barrier unit size, this bio will be split before calling raid1_read_request() or raid1_write_request(), this change the code logic more simple and clear. - In this patch wait_barrier() is moved from raid1_make_request() to raid1_write_request(). In raid_read_request(), original wait_barrier() is replaced by raid1_read_request(). The differnece is wait_read_barrier() only waits if array is frozen, using different barrier function in different code path makes the code more clean and easy to read. Changelog V4: - Add alloc_r1bio() to remove redundant r1bio memory allocation code. - Fix many typos in patch comments. - Use (PAGE_SHIFT - ilog2(sizeof(int))) to define BARRIER_BUCKETS_NR_BITS. V3: - Rebase the patch against latest upstream kernel code. - Many fixes by review comments from Neil, - Back to use pointers to replace arraries in struct r1conf - Remove total_barriers from struct r1conf - Add more patch comments to explain how/why the values of BARRIER_UNIT_SECTOR_SIZE and BARRIER_BUCKETS_NR are decided. - Use get_unqueued_pending() to replace get_all_pendings() and get_all_queued() - Increase bucket number from 512 to 1024 - Change code comments format by review from Shaohua. V2: - Use bio_split() to split the orignal bio if it goes across barrier unit bounday, to make the code more simple, by suggestion from Shaohua and Neil. - Use hash_long() to replace original linear hash, to avoid a possible confilict between resync I/O and sequential write I/O, by suggestion from Shaohua. - Add conf->total_barriers to record barrier depth, which is used to control number of parallel sync I/O barriers, by suggestion from Shaohua. - In V1 patch the bellowed barrier buckets related members in r1conf are allocated in memory page. To make the code more simple, V2 patch moves the memory space into struct r1conf, like this, - int nr_pending; - int nr_waiting; - int nr_queued; - int barrier; + int nr_pending[BARRIER_BUCKETS_NR]; + int nr_waiting[BARRIER_BUCKETS_NR]; + int nr_queued[BARRIER_BUCKETS_NR]; + int barrier[BARRIER_BUCKETS_NR]; This change is by the suggestion from Shaohua. - Remove some inrelavent code comments, by suggestion from Guoqing. - Add a missing wait_barrier() before jumping to retry_write, in raid1_make_write_request(). V1: - Original RFC patch for comments Signed-off-by: Coly Li <colyli@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Guoqing Jiang <gqjiang@suse.com> Reviewed-by: Neil Brown <neilb@suse.de> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/raid5: Don't reinvent the wheel but use existing llist APIByungchul Park2017-02-161-4/+2
| | | | | | | | | | | | | | | | | | | | | Although llist provides proper APIs, they are not used. Make them used. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md: fast clone bio in bio_clone_mddev()Ming Lei2017-02-156-22/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <hch@lst.de> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md: remove unnecessary check on mddevMing Lei2017-02-151-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | mddev is never NULL and neither is ->bio_set, so remove the check. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/raid1: use bio_clone_bioset_partial() in case of write behindMing Lei2017-02-151-5/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Write behind need to replace pages in bio's bvecs, and we have to clone a fresh bio with new bvec table, so use the introduced bio_clone_bioset_partial() for it. For other bio_clone_mddev() cases, we will use fast clone since they don't need to touch bvec table. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md: fail if mddev->bio_set can't be createdMing Lei2017-02-151-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current behaviour is to fall back to allocate bio from 'fs_bio_set', that isn't a correct way because it might cause deadlock. So this patch simply return failure if mddev->bio_set can't be created. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md: disable WRITE SAME if it fails in underlayer disksShaohua Li2017-02-144-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This makes md do the same thing as dm for write same IO failure. Please see 7eee4ae(dm: disable WRITE SAME if it fails) for details why we need this. We did a little bit different than dm. Instead of disabling writesame in the first IO error, we disable it till next writesame IO coming after the first IO error. This way we don't need to clone a bio. Also reported here: https://bugzilla.kernel.org/show_bug.cgi?id=118581 Suggested-by: NeilBrown <neilb@suse.com> Acked-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/raid5-cache: exclude reclaiming stripes in reclaim checkShaohua Li2017-02-133-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/raid5-cache: stripe reclaim only counts valid stripesShaohua Li2017-02-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When log space is tight, we try to reclaim stripes from log head. There are stripes which can't be reclaimed right now if some conditions are met. We skip such stripes but accidentally count them, which might cause no stripes are claimed. Fixing this by only counting valid stripes. Cc: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md: ensure md devices are freed before module is unloaded.NeilBrown2017-02-131-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit: cbd199837750 ("md: Fix unfortunate interaction with evms") change mddev_put() so that it would not destroy an md device while ->ctime was non-zero. Unfortunately, we didn't make sure to clear ->ctime when unloading the module, so it is possible for an md device to remain after module unload. An attempt to open such a device will trigger an invalid memory reference in: get_gendisk -> kobj_lookup -> exact_lock -> get_disk when tring to access disk->fops, which was in the module that has been removed. So ensure we clear ->ctime in md_exit(), and explain how that is useful, as it isn't immediately obvious when looking at the code. Fixes: cbd199837750 ("md: Fix unfortunate interaction with evms") Tested-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/r5cache: improve journal device efficiencySong Liu2017-02-132-20/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md/r5cache: enable chunk_aligned_read with write back cacheSong Liu2017-02-133-24/+168
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Chunk aligned read significantly reduces CPU usage of raid456. However, it is not safe to fully bypass the write back cache. This patch enables chunk aligned read with write back cache. For chunk aligned read, we track stripes in write back cache at a bigger granularity, "big_stripe". Each chunk may contain more than one stripe (for example, a 256kB chunk contains 64 4kB-page, so this chunk contain 64 stripes). For chunk_aligned_read, these stripes are grouped into one big_stripe, so we only need one lookup for the whole chunk. For each big_stripe, struct big_stripe_info tracks how many stripes of this big_stripe are in the write back cache. We count how many stripes of this big_stripe are in the write back cache. These counters are tracked in a radix tree (big_stripe_tree). r5c_tree_index() is used to calculate keys for the radix tree. chunk_aligned_read() calls r5c_big_stripe_cached() to look up big_stripe of each chunk in the tree. If this big_stripe is in the tree, chunk_aligned_read() aborts. This look up is protected by rcu_read_lock(). It is necessary to remember whether a stripe is counted in big_stripe_tree. Instead of adding new flag, we reuses existing flags: STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE. If either of these two flags are set, the stripe is counted in big_stripe_tree. This requires moving set_bit(STRIPE_R5C_PARTIAL_STRIPE) to r5c_try_caching_write(); and moving clear_bit of STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE to r5c_finish_stripe_write_out(). Signed-off-by: Song Liu <songliubraving@fb.com> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | raid5: only dispatch IO from raid5d for harddisk raidShaohua Li2017-02-132-2/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We made raid5 stripe handling multi-thread before. It works well for SSD. But for harddisk, the multi-threading creates more disk seek, so not always improve performance. For several hard disks based raid5, multi-threading is required as raid5d becames a bottleneck especially for sequential write. To overcome the disk seek issue, we only dispatch IO from raid5d if the array is harddisk based. Other threads can still handle stripes, but can't dispatch IO. Idealy, we should control IO dispatching order according to IO position interrnally. Right now we still depend on block layer, which isn't very efficient sometimes though. My setup has 9 harddisks, each disk can do around 180M/s sequential write. So in theory, the raid5 can do 180 * 8 = 1440M/s sequential write. The test machine uses an ATOM CPU. I measure sequential write with large iodepth bandwidth to raid array: without patch: ~600M/s without patch and group_thread_cnt=4: 750M/s with patch and group_thread_cnt=4: 950M/s with patch, group_thread_cnt=4, skip_copy=1: 1150M/s We are pretty close to the maximum bandwidth in the large iodepth iodepth case. The performance gap of small iodepth sequential write between software raid and theory value is still very big though, because we don't have an efficient pipeline. Cc: NeilBrown <neilb@suse.com> Cc: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * | md linear: fix a race between linear_add() and linear_congested()colyli@suse.de2017-02-132-5/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recently I receive a bug report that on Linux v3.0 based kerenl, hot add disk to a md linear device causes kernel crash at linear_congested(). From the crash image analysis, I find in linear_congested(), mddev->raid_disks contains value N, but conf->disks[] only has N-1 pointers available. Then a NULL pointer deference crashes the kernel. There is a race between linear_add() and linear_congested(), RCU stuffs used in these two functions cannot avoid the race. Since Linuv v4.0 RCU code is replaced by introducing mddev_suspend(). After checking the upstream code, it seems linear_congested() is not called in generic_make_request() code patch, so mddev_suspend() cannot provent it from being called. The possible race still exists. Here I explain how the race still exists in current code. For a machine has many CPUs, on one CPU, linear_add() is called to add a hard disk to a md linear device; at the same time on other CPU, linear_congested() is called to detect whether this md linear device is congested before issuing an I/O request onto it. Now I use a possible code execution time sequence to demo how the possible race happens, seq linear_add() linear_congested() 0 conf=mddev->private 1 oldconf=mddev->private 2 mddev->raid_disks++ 3 for (i=0; i<mddev->raid_disks;i++) 4 bdev_get_queue(conf->disks[i].rdev->bdev) 5 mddev->private=newconf In linear_add() mddev->raid_disks is increased in time seq 2, and on another CPU in linear_congested() the for-loop iterates conf->disks[i] by the increased mddev->raid_disks in time seq 3,4. But conf with one more element (which is a pointer to struct dev_info type) to conf->disks[] is not updated yet, accessing its structure member in time seq 4 will cause a NULL pointer deference fault. To fix this race, there are 2 parts of modification in the patch, 1) Add 'int raid_disks' in struct linear_conf, as a copy of mddev->raid_disks. It is initialized in linear_conf(), always being consistent with pointers number of 'struct dev_info disks[]'. When iterating conf->disks[] in linear_congested(), use conf->raid_disks to replace mddev->raid_disks in the for-loop, then NULL pointer deference will not happen again. 2) RCU stuffs are back again, and use kfree_rcu() in linear_add() to free oldconf memory. Because oldconf may be referenced as mddev->private in linear_congested(), kfree_rcu() makes sure that its memory will not be released until no one uses it any more. Also some code comments are added in this patch, to make this modification to be easier understandable. This patch can be applied for kernels since v4.0 after commit: 3be260cc18f8 ("md/linear: remove rcu protections in favour of suspend/resume"). But this bug is reported on Linux v3.0 based kernel, for people who maintain kernels before Linux v4.0, they need to do some back back port to this patch. Changelog: - V3: add 'int raid_disks' in struct linear_conf, and use kfree_rcu() to replace rcu_call() in linear_add(). - v2: add RCU stuffs by suggestion from Shaohua and Neil. - v1: initial effort. Signed-off-by: Coly Li <colyli@suse.de> Cc: Shaohua Li <shli@fb.com> Cc: Neil Brown <neilb@suse.com> Cc: stable@vger.kernel.org Signed-off-by: Shaohua Li <shli@fb.com>
* | | Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds2017-02-241-2/+4
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block updates and fixes from Jens Axboe: - NVMe updates and fixes that missed the first pull request. This includes bug fixes, and support for autonomous power management. - Fix from Christoph for missing clear of the request payload, causing a problem with (at least) the storvsc driver. - Further fixes for the queue/bdi life time issues from Jan. - The Kconfig mq scheduler update from me. - Fixing a use-after-free in dm-rq, spotted by Bart, introduced in this merge window. - Three fixes for nbd from Josef. - Bug fix from Omar, fixing a bug in sas transport code that oopses when bsg ioctls were used. From Omar. - Improvements to the queue restart and tag wait from from Omar. - Set of fixes for the sed/opal code from Scott. - Three trivial patches to cciss from Tobin * 'for-linus' of git://git.kernel.dk/linux-block: (41 commits) dm-rq: don't dereference request payload after ending request blk-mq-sched: separate mark hctx and queue restart operations blk-mq: use sbq wait queues instead of restart for driver tags block/sed-opal: Propagate original error message to userland. nvme/pci: re-check security protocol support after reset block/sed-opal: Introduce free_opal_dev to free the structure and clean up state nvme: detect NVMe controller in recent MacBooks nvme-rdma: add support for host_traddr nvmet-rdma: Fix error handling nvmet-rdma: use nvme cm status helper nvme-rdma: move nvme cm status helper to .h file nvme-fc: don't bother to validate ioccsz and iorcsz nvme/pci: No special case for queue busy on IO nvme/core: Fix race kicking freed request_queue nvme/pci: Disable on removal when disconnected nvme: Enable autonomous power state transitions nvme: Add a quirk mechanism that uses identify_ctrl nvme: make nvmf_register_transport require a create_ctrl callback nvme: Use CNS as 8-bit field and avoid endianness conversion nvme: add semicolon in nvme_command setting ...
| * | | dm-rq: don't dereference request payload after ending requestJens Axboe2017-02-241-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Bart reported a case where dm would crash with use-after-free poison. This is due to dm_softirq_done() accessing memory associated with a request after calling end_request on it. This is most visible on !blk-mq, since we free the memory immediately for that case. Reported-by: Bart Van Assche <bart.vanassche@sandisk.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Fixes: eb8db831be80 ("dm: always defer request allocation to the owner of the request_queue") Signed-off-by: Jens Axboe <axboe@fb.com>
* | | | Merge tag 'dm-4.11-changes' of ↵Linus Torvalds2017-02-2116-227/+854
|\ \ \ \ | |/ / / |/| | / | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - Fix dm-raid transient device failure processing and other smaller tweaks. - Add journal support to the DM raid target to close the 'write hole' on raid 4/5/6. - Fix dm-cache corruption, due to rounding bug, when cache exceeds 2TB. - Add 'metadata2' feature to dm-cache to separate the dirty bitset out from other cache metadata. This improves speed of shutting down a large cache device (which implies writing out dirty bits). - Fix a memory leak during dm-stats data structure destruction. - Fix a DM multipath round-robin path selector performance regression that was caused by less precise balancing across all paths. - Lastly, introduce a DM core fix for a long-standing DM snapshot deadlock that is rooted in the complexity of the device stack used in conjunction with block core maintaining bios on current->bio_list to manage recursion in generic_make_request(). A more comprehensive fix to block core (and its hook in the cpu scheduler) would be wonderful but this DM-specific fix is pragmatic considering how difficult it has been to make progress on a generic fix. * tag 'dm-4.11-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (22 commits) dm: flush queued bios when process blocks to avoid deadlock dm round robin: revert "use percpu 'repeat_count' and 'current_path'" dm stats: fix a leaked s->histogram_boundaries array dm space map metadata: constify dm_space_map structures dm cache metadata: use cursor api in blocks_are_clean_separate_dirty() dm persistent data: add cursor skip functions to the cursor APIs dm cache metadata: use dm_bitset_new() to create the dirty bitset in format 2 dm bitset: add dm_bitset_new() dm cache metadata: name the cache block that couldn't be loaded dm cache metadata: add "metadata2" feature dm cache metadata: use bitset cursor api to load discard bitset dm bitset: introduce cursor api dm btree: use GFP_NOFS in dm_btree_del() dm space map common: memcpy the disk root to ensure it's arch aligned dm block manager: add unlikely() annotations on dm_bufio error paths dm cache: fix corruption seen when using cache > 2TB dm raid: cleanup awkward branching in raid_message() option processing dm raid: use mddev rather than rdev->mddev dm raid: use read_disk_sb() throughout dm raid: add raid4/5/6 journaling support ...
| * | dm: flush queued bios when process blocks to avoid deadlockMikulas Patocka2017-02-171-0/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit df2cb6daa4 ("block: Avoid deadlocks with bio allocation by stacking drivers") created a workqueue for every bio set and code in bio_alloc_bioset() that tries to resolve some low-memory deadlocks by redirecting bios queued on current->bio_list to the workqueue if the system is low on memory. However other deadlocks (see below **) may happen, without any low memory condition, because generic_make_request is queuing bios to current->bio_list (rather than submitting them). ** the related dm-snapshot deadlock is detailed here: https://www.redhat.com/archives/dm-devel/2016-July/msg00065.html Fix this deadlock by redirecting any bios on current->bio_list to the bio_set's rescue workqueue on every schedule() call. Consequently, when the process blocks on a mutex, the bios queued on current->bio_list are dispatched to independent workqueus and they can complete without waiting for the mutex to be available. The structure blk_plug contains an entry cb_list and this list can contain arbitrary callback functions that are called when the process blocks. To implement this fix DM (ab)uses the onstack plug's cb_list interface to get its flush_current_bio_list() called at schedule() time. This fixes the snapshot deadlock - if the map method blocks, flush_current_bio_list() will be called and it redirects bios waiting on current->bio_list to appropriate workqueues. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1267650 Depends-on: df2cb6daa4 ("block: Avoid deadlocks with bio allocation by stacking drivers") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm round robin: revert "use percpu 'repeat_count' and 'current_path'"Mike Snitzer2017-02-171-53/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sloppy nature of lockless access to percpu pointers (s->current_path) in rr_select_path(), from multiple threads, is causing some paths to used more than others -- which results in less IO performance being observed. Revert these upstream commits to restore truly symmetric round-robin IO submission in DM multipath: b0b477c dm round robin: use percpu 'repeat_count' and 'current_path' 802934b dm round robin: do not use this_cpu_ptr() without having preemption disabled There is no benefit to all this complexity if repeat_count = 1 (which is the recommended default). Cc: stable@vger.kernel.org # 4.6+ Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm stats: fix a leaked s->histogram_boundaries arrayMikulas Patocka2017-02-161-0/+1
| | | | | | | | | | | | | | | | | | | | | Fixes: dfcfac3e4cd9 ("dm stats: collect and report histogram of IO latencies") Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm space map metadata: constify dm_space_map structuresBhumika Goyal2017-02-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Declare dm_space_map structures as const as they are only passed as an argument to the function memcpy. This argument is of type const void *, so dm_space_map structures having this property can be declared as const. File size before: text data bss dec hex filename 4889 240 0 5129 1409 dm-space-map-metadata.o File size after: text data bss dec hex filename 5139 0 0 5139 1413 dm-space-map-metadata.o Signed-off-by: Bhumika Goyal <bhumirks@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm cache metadata: use cursor api in blocks_are_clean_separate_dirty()Mike Snitzer2017-02-161-7/+26
| | | | | | | | | | | | Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm persistent data: add cursor skip functions to the cursor APIsJoe Thornber2017-02-166-0/+70
| | | | | | | | | | | | | | | Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm cache metadata: use dm_bitset_new() to create the dirty bitset in format 2Joe Thornber2017-02-161-11/+11
| | | | | | | | | | | | | | | | | | | | | Big speed up with large configs. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm bitset: add dm_bitset_new()Joe Thornber2017-02-162-0/+58
| | | | | | | | | | | | | | | | | | | | | A more efficient way of creating a populated bitset. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm cache metadata: name the cache block that couldn't be loadedMike Snitzer2017-02-161-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | Improves __load_mapping_v1() and __load_mapping_v2() DMERR messages to explicitly name the cache block number whose mapping couldn't be loaded. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm cache metadata: add "metadata2" featureJoe Thornber2017-02-163-53/+274
| | | | | | | | | | | | | | | | | | | | | | | | | | | If "metadata2" is provided as a table argument when creating/loading a cache target a more compact metadata format, with separate dirty bits, is used. "metadata2" improves speed of shutting down a cache target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm cache metadata: use bitset cursor api to load discard bitsetJoe Thornber2017-02-161-20/+28
| | | | | | | | | | | | | | | Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm bitset: introduce cursor apiJoe Thornber2017-02-162-0/+91
| | | | | | | | | | | | | | | Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm btree: use GFP_NOFS in dm_btree_del()Joe Thornber2017-02-161-1/+6
| | | | | | | | | | | | | | | | | | | | | dm_btree_del() is called from an ioctl so don't recurse into FS. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * | dm space map common: memcpy the disk root to ensure it's arch alignedJoe Thornber2017-02-161-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The metadata_space_map_root passed to sm_ll_open_metadata() may or may not be arch aligned, use memcpy to ensure it is. This is not a fast path so the extra memcpy doesn't hurt us. Long-term it'd be better to use the kernel's alignment infrastructure to remove the memcpy()s that are littered across persistent-data (btree, array, space-maps, etc). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>