Commit Graph

4064 Commits

Author SHA1 Message Date
Mikulas Patocka 0dc10e50f2 md: fix bug due to nested suspend
The patch c7bfced9a6 committed to 4.4-rc
causes crash in LVM test shell/lvchange-raid.sh. The kernel crashes with
this BUG, the reason is that we attempt to suspend a device that is
already suspended. See also
https://bugzilla.redhat.com/show_bug.cgi?id=1283491

This patch fixes the bug by changing functions mddev_suspend and
mddev_resume to always nest.
The number of nested calls to mddev_nested_suspend is kept in the
variable mddev->suspended.
[neilb: made mddev_suspend() always nest instead of introduce mddev_nested_suspend]

kernel BUG at drivers/md/md.c:317!
CPU: 3 PID: 32754 Comm: lvm Not tainted 4.4.0-rc2 #1
task: 0000000047076040 ti: 0000000047014000 task.ti: 0000000047014000

     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
PSW: 00001000000001000000000000001111 Not tainted
r00-03  000000000804000f 00000000102c5280 0000000010c7522c 000000007e3d1810
r04-07  0000000010c6f000 000000004ef37f20 000000007e3d1dd0 000000007e3d1810
r08-11  000000007c9f1600 0000000000000000 0000000000000001 ffffffffffffffff
r12-15  0000000010c1d000 0000000000000041 00000000f98d63c8 00000000f98e49e4
r16-19  00000000f98e49e4 00000000c138fd06 00000000f98d63c8 0000000000000001
r20-23  0000000000000002 000000004ef37f00 00000000000000b0 00000000000001d1
r24-27  00000000424783a0 000000007e3d1dd0 000000007e3d1810 00000000102b2000
r28-31  0000000000000001 0000000047014840 0000000047014930 0000000000000001
sr00-03  0000000007040800 0000000000000000 0000000000000000 0000000007040800
sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000102c538c 00000000102c5390
 IIR: 03ffe01f    ISR: 0000000000000000  IOR: 00000000102b2748
 CPU:        3   CR30: 0000000047014000 CR31: 0000000000000000
 ORIG_R28: 00000000000000b0
 IAOQ[0]: mddev_suspend+0x10c/0x160 [md_mod]
 IAOQ[1]: mddev_suspend+0x110/0x160 [md_mod]
 RP(r2): raid1_add_disk+0xd4/0x2c0 [raid1]
Backtrace:
 [<0000000010c7522c>] raid1_add_disk+0xd4/0x2c0 [raid1]
 [<0000000010c20078>] raid_resume+0x390/0x418 [dm_raid]
 [<00000000105833e8>] dm_table_resume_targets+0xc0/0x188 [dm_mod]
 [<000000001057f784>] dm_resume+0x144/0x1e0 [dm_mod]
 [<0000000010587dd4>] dev_suspend+0x1e4/0x568 [dm_mod]
 [<0000000010589278>] ctl_ioctl+0x1e8/0x428 [dm_mod]
 [<0000000010589518>] dm_compat_ctl_ioctl+0x18/0x68 [dm_mod]
 [<0000000040377b88>] compat_SyS_ioctl+0xd0/0x1558

Fixes: c7bfced9a6 ("md: suspend i/o during runtime blk_integrity_unregister")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-12-18 15:19:16 +11:00
Shaohua Li 9b15603dbd MD: change journal disk role to disk 0
Neil pointed out setting journal disk role to raid_disks will confuse
reshape if we support reshape eventually. Switching the role to 0 (we
should be fine as long as the value >=0) and skip sysfs file creation to
avoid error.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-12-18 15:19:16 +11:00
Artur Paszkiewicz cc57858831 md/raid10: fix data corruption and crash during resync
The commit c31df25f20 ("md/raid10: make sync_request_write() call
bio_copy_data()") replaced manual data copying with bio_copy_data() but
it doesn't work as intended. The source bio (fbio) is already processed,
so its bvec_iter has bi_size == 0 and bi_idx == bi_vcnt.  Because of
this, bio_copy_data() either does not copy anything, or worse, copies
data from the ->bi_next bio if it is set.  This causes wrong data to be
written to drives during resync and sometimes lockups/crashes in
bio_copy_data():

[  517.338478] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [md126_raid10:3319]
[  517.347324] Modules linked in: raid10 xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw iptable_filter ip_tables x86_pkg_temp_thermal coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul cryptd shpchp pcspkr ipmi_si ipmi_msghandler tpm_crb acpi_power_meter acpi_cpufreq ext4 mbcache jbd2 sr_mod cdrom sd_mod e1000e ax88179_178a usbnet mii ahci ata_generic crc32c_intel libahci ptp pata_acpi libata pps_core wmi sunrpc dm_mirror dm_region_hash dm_log dm_mod
[  517.440555] CPU: 0 PID: 3319 Comm: md126_raid10 Not tainted 4.3.0-rc6+ #1
[  517.448384] Hardware name: Intel Corporation PURLEY/PURLEY, BIOS PLYDCRB1.86B.0055.D14.1509221924 09/22/2015
[  517.459768] task: ffff880153773980 ti: ffff880150df8000 task.ti: ffff880150df8000
[  517.468529] RIP: 0010:[<ffffffff812e1888>]  [<ffffffff812e1888>] bio_copy_data+0xc8/0x3c0
[  517.478164] RSP: 0018:ffff880150dfbc98  EFLAGS: 00000246
[  517.484341] RAX: ffff880169356688 RBX: 0000000000001000 RCX: 0000000000000000
[  517.492558] RDX: 0000000000000000 RSI: ffffea0001ac2980 RDI: ffffea0000d835c0
[  517.500773] RBP: ffff880150dfbd08 R08: 0000000000000001 R09: ffff880153773980
[  517.508987] R10: ffff880169356600 R11: 0000000000001000 R12: 0000000000010000
[  517.517199] R13: 000000000000e000 R14: 0000000000000000 R15: 0000000000001000
[  517.525412] FS:  0000000000000000(0000) GS:ffff880174a00000(0000) knlGS:0000000000000000
[  517.534844] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  517.541507] CR2: 00007f8a044d5fed CR3: 0000000169504000 CR4: 00000000001406f0
[  517.549722] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  517.557929] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  517.566144] Stack:
[  517.568626]  ffff880174a16bc0 ffff880153773980 ffff880169356600 0000000000000000
[  517.577659]  0000000000000001 0000000000000001 ffff880153773980 ffff88016a61a800
[  517.586715]  ffff880150dfbcf8 0000000000000001 ffff88016dd209e0 0000000000001000
[  517.595773] Call Trace:
[  517.598747]  [<ffffffffa043ef95>] raid10d+0xfc5/0x1690 [raid10]
[  517.605610]  [<ffffffff816697ae>] ? __schedule+0x29e/0x8e2
[  517.611987]  [<ffffffff814ff206>] md_thread+0x106/0x140
[  517.618072]  [<ffffffff810c1d80>] ? wait_woken+0x80/0x80
[  517.624252]  [<ffffffff814ff100>] ? super_1_load+0x520/0x520
[  517.630817]  [<ffffffff8109ef89>] kthread+0xc9/0xe0
[  517.636506]  [<ffffffff8109eec0>] ? flush_kthread_worker+0x70/0x70
[  517.643653]  [<ffffffff8166d99f>] ret_from_fork+0x3f/0x70
[  517.649929]  [<ffffffff8109eec0>] ? flush_kthread_worker+0x70/0x70

Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Reviewed-by: Shaohua Li <shli@kernel.org>
Cc: stable@vger.kernel.org (v4.2+)
Fixes: c31df25f20 ("md/raid10: make sync_request_write() call bio_copy_data()")
Signed-off-by: NeilBrown <neilb@suse.com>
2015-12-18 15:19:16 +11:00
Nikolay Borisov 18d03e8c25 dm thin: fix race condition when destroying thin pool workqueue
When a thin pool is being destroyed delayed work items are
cancelled using cancel_delayed_work(), which doesn't guarantee that on
return the delayed item isn't running.  This can cause the work item to
requeue itself on an already destroyed workqueue.  Fix this by using
cancel_delayed_work_sync() which guarantees that on return the work item
is not running anymore.

Fixes: 905e51b39a ("dm thin: commit outstanding data every second")
Fixes: 85ad643b7e ("dm thin: add timeout to stop out-of-data-space mode holding IO forever")
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-12-17 15:47:20 -05:00
Mike Snitzer 512167788a dm space map metadata: remove unused variable in brb_pop()
Remove the unused struct block_op pointer that was inadvertantly
introduced, via cut-and-paste of previous brb_op() code, as part of
commit 50dd842ad.

(Cc'ing stable@ because commit 50dd842ad did)

Fixes: 50dd842ad ("dm space map metadata: fix ref counting bug when bootstrapping a new space map")
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-12-14 09:26:01 -05:00
Sami Tolvanen 0cc37c2df4 dm verity: add ignore_zero_blocks feature
If ignore_zero_blocks is enabled dm-verity will return zeroes for blocks
matching a zero hash without validating the content.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:03 -05:00
Sami Tolvanen a739ff3f54 dm verity: add support for forward error correction
Add support for correcting corrupted blocks using Reed-Solomon.

This code uses RS(255, N) interleaved across data and hash
blocks. Each error-correcting block covers N bytes evenly
distributed across the combined total data, so that each byte is a
maximum distance away from the others. This makes it possible to
recover from several consecutive corrupted blocks with relatively
small space overhead.

In addition, using verity hashes to locate erasures nearly doubles
the effectiveness of error correction. Being able to detect
corrupted blocks also improves performance, because only corrupted
blocks need to corrected.

For a 2 GiB partition, RS(255, 253) (two parity bytes for each
253-byte block) can correct up to 16 MiB of consecutive corrupted
blocks if erasures can be located, and 8 MiB if they cannot, with
16 MiB space overhead.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:03 -05:00
Sami Tolvanen bb4d73ac5e dm verity: factor out verity_for_bv_block()
verity_for_bv_block() will be re-used by optional dm-verity object.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:02 -05:00
Sami Tolvanen ffa393807c dm verity: factor out structures and functions useful to separate object
Prepare for an optional verity object to make use of existing dm-verity
structures and functions.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:01 -05:00
Sami Tolvanen 03045cbafa dm verity: move dm-verity.c to dm-verity-target.c
Prepare for extending dm-verity with an optional object.  Follows the
naming convention used by other DM targets (e.g. dm-cache and dm-era).

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:01 -05:00
Sami Tolvanen 753c1fd028 dm verity: separate function for parsing opt args
Move optional argument parsing into a separate function to make it
easier to add more of them without making verity_ctr even longer.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:00 -05:00
Sami Tolvanen 6dbeda3469 dm verity: clean up duplicate hashing code
Handle dm-verity salting in one place to simplify the code.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:00 -05:00
Mike Snitzer ba503835ad dm btree: factor out need_insert() helper
Eliminates code duplication within insert().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:59 -05:00
Anup Limbu 86a49e2dac dm bufio: use BUG_ON instead of conditional call to BUG
Signed-off-by: Anup Limbu <anuplimbu14@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:58 -05:00
Mikulas Patocka 86bad0c707 dm bufio: store stacktrace in buffers to help find buffer leaks
The option DM_DEBUG_BLOCK_STACK_TRACING is moved from persistent-data
directory to device mapper directory because it will now be used by
persistent-data and bufio.  When the option is enabled, each bufio buffer
stores the stacktrace of the last dm_bufio_get(), dm_bufio_read() or
dm_bufio_new() call that increased the hold count to 1.  The buffer's
stacktrace is printed if the buffer was not released before the bufio
client is destroyed.

When DM_DEBUG_BLOCK_STACK_TRACING is enabled, any bufio buffer leaks are
considered warnings - i.e. the kernel continues afterwards.  If not
enabled, buffer leaks are considered BUGs and the kernel with crash.
Reasoning on this disposition is: if we only ever warned on buffer leaks
users would generally ignore them and the problematic code would never
get fixed.

Successfully used to find source of bufio leaks fixed with commit
fce079f63c3 ("dm btree: fix bufio buffer leaks in dm_btree_del() error
path").

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:58 -05:00
Mikulas Patocka f98c8f7970 dm bufio: return NULL to improve code clarity
A small code cleanup in new_read() - return NULL instead of b (although
b is NULL at this point).  This function is not returning pointer to the
buffer, it is returning a pointer to the bufffer's data, thus it makes
no sense to return the variable b.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:57 -05:00
Mikulas Patocka 313c9b9736 dm block manager: cleanup code that prints stacktrace
There is no need to record stack trace and immediately print it.  Just
use dump_stack() to print the current stack.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:56 -05:00
Mikulas Patocka fe3265b180 dm: don't save and restore bi_private
Device mapper used the field bi_private to point to dm_target_io. However,
since kernel 3.15, the bi_private field is unused, and so the targets do
not need to save and restore this field.

This patch removes code that saves and restores bi_private from dm-cache,
dm-snapshot and dm-verity.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:56 -05:00
Joe Thornber 086fbbbda9 dm thin metadata: make dm_thin_find_mapped_range() atomic
Refactor dm_thin_find_mapped_range() so that it takes the read lock on
the metadata's lock; rather than relying on finer grained locking that
is pushed down inside dm_thin_find_next_mapped_block() and
dm_thin_find_block().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:55 -05:00
Joe Thornber 3d5f67332a dm thin metadata: speed up discard of partially mapped volumes
Use dm_btree_lookup_next() to more quickly discard partially mapped
volumes.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:30:56 -05:00
Joe Thornber ed8b45a367 dm btree: fix bufio buffer leaks in dm_btree_del() error path
If dm_btree_del()'s call to push_frame() fails, e.g. due to
btree_node_validator finding invalid metadata, the dm_btree_del() error
path must unlock all frames (which have active dm-bufio buffers) that
were pushed onto the del_stack.

Otherwise, dm_bufio_client_destroy() will BUG_ON() because dm-bufio
buffers have leaked, e.g.:
  device-mapper: bufio: leaked buffer 3, hold count 1, list 0

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-12-10 10:30:18 -05:00
Joe Thornber 50dd842ad8 dm space map metadata: fix ref counting bug when bootstrapping a new space map
When applying block operations (BOPs) do not remove them from the
uncommitted BOP ring-buffer until after they've been applied -- in case
we recurse.

Also, perform BOP_INC operation, in dm_sm_metadata_create() and
sm_metadata_extend(), in terms of the uncommitted BOP ring-buffer rather
than using direct calls to sm_ll_inc().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-12-09 13:27:25 -05:00
Joe Thornber 49e99fc717 dm thin metadata: fix bug when taking a metadata snapshot
When you take a metadata snapshot the btree roots for the mapping and
details tree need to have their reference counts incremented so they
persist for the lifetime of the metadata snap.

The roots being incremented were those currently written in the
superblock, which could possibly be out of date if concurrent IO is
triggering new mappings, breaking of sharing, etc.

Fix this by performing a commit with the metadata lock held while taking
a metadata snapshot.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-12-09 13:18:12 -05:00
Masanari Iida e3d132d123 treewide: Fix typos in printk
This patch fix multiple spelling typos found in
various part of kernel.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-12-08 14:59:19 +01:00
Joe Thornber 993ceab919 dm thin metadata: fix bug in dm_thin_remove_range()
dm_btree_remove_leaves() only unmaps a contiguous region so we need a
loop, in __remove_range(), to handle ranges that contain multiple
regions.

A new btree function, dm_btree_lookup_next(), is introduced which is
more efficiently able to skip over regions of the thin device which
aren't mapped.  __remove_range() uses dm_btree_lookup_next() for each
iteration of __remove_range()'s loop.

Also, improve description of dm_btree_remove_leaves().

Fixes: 6550f075 ("dm thin metadata: add dm_thin_remove_range()")
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.1+
2015-12-02 13:26:49 -05:00
Mike Snitzer 30ce6e1cc5 dm btree: fix leak of bufio-backed block in btree_split_sibling error path
The block allocated at the start of btree_split_sibling() is never
released if later insert_at() fails.

Fix this by releasing the previously allocated bufio block using
unlock_block().

Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-12-02 13:20:34 -05:00
Mike Snitzer 0fcb04d593 dm thin: fix regression in advertised discard limits
When establishing a thin device's discard limits we cannot rely on the
underlying thin-pool device's discard capabilities (which are inherited
from the thin-pool's underlying data device) given that DM thin devices
must provide discard support even when the thin-pool's underlying data
device doesn't support discards.

Users were exposed to this thin device discard limits regression if
their thin-pool's underlying data device does _not_ support discards.
This regression caused all upper-layers that called the
blkdev_issue_discard() interface to not be able to issue discards to
thin devices (because discard_granularity was 0).  This regression
wasn't caught earlier because the device-mapper-test-suite's extensive
'thin-provisioning' discard tests are only ever performed against
thin-pool's with data devices that support discards.

Fix is to have thin_io_hints() test the pool's 'discard_enabled' feature
rather than inferring whether or not a thin device's discard support
should be enabled by looking at the thin-pool's discard_granularity.

Fixes: 216076705 ("dm thin: disable discard support for thin devices if pool's is disabled")
Reported-by: Mike Gerber <mike@sprachgewalt.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.1+
2015-11-23 14:54:46 -05:00
Mikulas Patocka bcbd94ff48 dm crypt: fix a possible hang due to race condition on exit
A kernel thread executes __set_current_state(TASK_INTERRUPTIBLE),
__add_wait_queue, spin_unlock_irq and then tests kthread_should_stop().
It is possible that the processor reorders memory accesses so that
kthread_should_stop() is executed before __set_current_state().  If such
reordering happens, there is a possible race on thread termination:

CPU 0:
calls kthread_should_stop()
	it tests KTHREAD_SHOULD_STOP bit, returns false
CPU 1:
calls kthread_stop(cc->write_thread)
	sets the KTHREAD_SHOULD_STOP bit
	calls wake_up_process on the kernel thread, that sets the thread
	state to TASK_RUNNING
CPU 0:
sets __set_current_state(TASK_INTERRUPTIBLE)
spin_unlock_irq(&cc->write_thread_wait.lock)
schedule() - and the process is stuck and never terminates, because the
	state is TASK_INTERRUPTIBLE and wake_up_process on CPU 1 already
	terminated

Fix this race condition by using a new flag DM_CRYPT_EXIT_THREAD to
signal that the kernel thread should exit.  The flag is set and tested
while holding cc->write_thread_wait.lock, so there is no possibility of
racy access to the flag.

Also, remove the unnecessary set_task_state(current, TASK_RUNNING)
following the schedule() call.  When the process was woken up, its state
was already set to TASK_RUNNING.  Other kernel code also doesn't set the
state to TASK_RUNNING following schedule() (for example,
do_wait_for_common in completion.c doesn't do it).

Fixes: dc2676210c ("dm crypt: offload writes to thread")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-11-19 13:38:30 -05:00
Junichi Nomura 43e43c9ea6 dm mpath: fix infinite recursion in ioctl when no paths and !queue_if_no_path
In multipath_prepare_ioctl(),
  - pgpath is a path selected from available paths
  - m->queue_io is true if we cannot send a request immediately to
    paths, either because:
      * there is no available path
      * the path group needs activation (pg_init)
          - pg_init is not started
          - pg_init is still running
  - m->queue_if_no_path is true if the device is configured to queue
    I/O if there are no available paths

If !pgpath && !m->queue_if_no_path, the handler should return -EIO.
However in the course of refactoring the condition check has broken
and returns success in that case.  Since bdev points to the dm device
itself, dm_blk_ioctl() calls __blk_dev_driver_ioctl() for itself and
recurses until crash.

You could reproduce the problem like this:

  # dmsetup create mp --table '0 1024 multipath 0 0 0 0'
  # sg_inq /dev/mapper/mp
  <crash>
  [  172.648615] BUG: unable to handle kernel paging request at fffffffc81b10268
  [  172.662843] PGD 19dd067 PUD 0
  [  172.666269] Thread overran stack, or stack corrupted
  [  172.671808] Oops: 0000 [#1] SMP
  ...

Fix the condition check with some clarifications.

Fixes: e56f81e0b0 ("dm: refactor ioctl handling")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-11-17 14:19:00 -05:00
Mike Snitzer 647a20d5ca dm: do not reuse dm_blk_ioctl block_device input as local variable
(Ab)using the @bdev passed to dm_blk_ioctl() opens the potential for
targets' .prepare_ioctl to fail if they go on to check the bdev for
!NULL.

Fixes: e56f81e0b0 ("dm: refactor ioctl handling")
Reported-by: Junichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-11-17 14:18:49 -05:00
Junichi Nomura 5bbbfdf685 dm: fix ioctl retry termination with signal
dm-mpath retries ioctl, when no path is readily available and the device
is configured to queue I/O in such a case. If you want to stop the retry
before multipathd decides to turn off queueing mode, you could send
signal for the process to exit from the loop.

However the check of fatal signal has not carried along when commit
6c182cd88d ("dm mpath: fix ioctl deadlock when no paths") moved the
loop from dm-mpath to dm core. As a result, we can't terminate such
a process in the retry loop.

Easy reproducer of the situation is:

  # dmsetup create mp --table '0 1024 multipath 0 0 0 0'
  # dmsetup message mp 0 'queue_if_no_path'
  # sg_inq /dev/mapper/mp

then you should be able to terminate sg_inq by pressing Ctrl+C.

Fixes: 6c182cd88d ("dm mpath: fix ioctl deadlock when no paths")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-11-17 14:04:32 -05:00
Mike Snitzer 172c238612 dm thin: restore requested 'error_if_no_space' setting on OODS to WRITE transition
A thin-pool that is in out-of-data-space (OODS) mode may transition back
to write mode -- without the admin adding more space to the thin-pool --
if/when blocks are released (either by deleting thin devices or
discarding provisioned blocks).

But as part of the thin-pool's earlier transition to out-of-data-space
mode the thin-pool may have set the 'error_if_no_space' flag to true if
the no_space_timeout expires without more space having been made
available.  That implementation detail, of changing the pool's
error_if_no_space setting, needs to be reset back to the default that
the user specified when the thin-pool's table was loaded.

Otherwise we'll drop the user requested behaviour on the floor when this
out-of-data-space to write mode transition occurs.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Fixes: 2c43fd26e4 ("dm thin: fix missing out-of-data-space to write mode transition if blocks are released")
Cc: stable@vger.kernel.org
2015-11-16 09:36:08 -05:00
Linus Torvalds 3419b45039 Merge branch 'for-4.4/io-poll' of git://git.kernel.dk/linux-block
Pull block IO poll support from Jens Axboe:
 "Various groups have been doing experimentation around IO polling for
  (really) fast devices.  The code has been reviewed and has been
  sitting on the side for a few releases, but this is now good enough
  for coordinated benchmarking and further experimentation.

  Currently O_DIRECT sync read/write are supported.  A framework is in
  the works that allows scalable stats tracking so we can auto-tune
  this.  And we'll add libaio support as well soon.  Fow now, it's an
  opt-in feature for test purposes"

* 'for-4.4/io-poll' of git://git.kernel.dk/linux-block:
  direct-io: be sure to assign dio->bio_bdev for both paths
  directio: add block polling support
  NVMe: add blk polling support
  block: add block polling support
  blk-mq: return tag/queue combo in the make_request_fn handlers
  block: change ->make_request_fn() and users to return a queue cookie
2015-11-10 17:23:49 -08:00
Linus Torvalds 3934bbc044 config fix for md
config dependency needed as md/raid5 now uses crc32c
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Merge tag 'md/4.4-rc0-fix' of git://neil.brown.name/md

Pull config fix for md from Neil Brown:
 "New config dependency needed as md/raid5 now uses crc32c"

* tag 'md/4.4-rc0-fix' of git://neil.brown.name/md:
  raid5-cache: add crc32c Kconfig dependency
2015-11-10 12:13:00 -08:00
Arnd Bergmann 14f09e2f9b raid5-cache: add crc32c Kconfig dependency
The recent change of the raid5-cache code to use crc32c instead
of crc32 causes link errors when CONFIG_LIBCRC32C is disabled:

drivers/built-in.o: In function crc32c'
core.c:(.text+0x1c6060): undefined reference to `crc32c'

This adds an explicit 'select' statement like all other users
of this function do.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 5cb2fbd6ea ("raid5-cache: use crc32c checksum")
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-09 09:09:52 +11:00
Linus Torvalds ad804a0b2a Merge branch 'akpm' (patches from Andrew)
Merge second patch-bomb from Andrew Morton:

 - most of the rest of MM

 - procfs

 - lib/ updates

 - printk updates

 - bitops infrastructure tweaks

 - checkpatch updates

 - nilfs2 update

 - signals

 - various other misc bits: coredump, seqfile, kexec, pidns, zlib, ipc,
   dma-debug, dma-mapping, ...

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (102 commits)
  ipc,msg: drop dst nil validation in copy_msg
  include/linux/zutil.h: fix usage example of zlib_adler32()
  panic: release stale console lock to always get the logbuf printed out
  dma-debug: check nents in dma_sync_sg*
  dma-mapping: tidy up dma_parms default handling
  pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
  kexec: use file name as the output message prefix
  fs, seqfile: always allow oom killer
  seq_file: reuse string_escape_str()
  fs/seq_file: use seq_* helpers in seq_hex_dump()
  coredump: change zap_threads() and zap_process() to use for_each_thread()
  coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
  signal: remove jffs2_garbage_collect_thread()->allow_signal(SIGCONT)
  signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
  signal: turn dequeue_signal_lock() into kernel_dequeue_signal()
  signals: kill block_all_signals() and unblock_all_signals()
  nilfs2: fix gcc uninitialized-variable warnings in powerpc build
  nilfs2: fix gcc unused-but-set-variable warnings
  MAINTAINERS: nilfs2: add header file for tracing
  nilfs2: add tracepoints for analyzing reading and writing metadata files
  ...
2015-11-07 14:32:45 -08:00
Linus Torvalds 75021d2859 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial updates from Jiri Kosina:
 "Trivial stuff from trivial tree that can be trivially summed up as:

   - treewide drop of spurious unlikely() before IS_ERR() from Viresh
     Kumar

   - cosmetic fixes (that don't really affect basic functionality of the
     driver) for pktcdvd and bcache, from Julia Lawall and Petr Mladek

   - various comment / printk fixes and updates all over the place"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  bcache: Really show state of work pending bit
  hwmon: applesmc: fix comment typos
  Kconfig: remove comment about scsi_wait_scan module
  class_find_device: fix reference to argument "match"
  debugfs: document that debugfs_remove*() accepts NULL and error values
  net: Drop unlikely before IS_ERR(_OR_NULL)
  mm: Drop unlikely before IS_ERR(_OR_NULL)
  fs: Drop unlikely before IS_ERR(_OR_NULL)
  drivers: net: Drop unlikely before IS_ERR(_OR_NULL)
  drivers: misc: Drop unlikely before IS_ERR(_OR_NULL)
  UBI: Update comments to reflect UBI_METAONLY flag
  pktcdvd: drop null test before destroy functions
2015-11-07 13:05:44 -08:00
Jens Axboe dece16353e block: change ->make_request_fn() and users to return a queue cookie
No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.

Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
2015-11-07 10:40:46 -07:00
Mel Gorman d0164adc89 mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Petr Mladek 8d090f4731 bcache: Really show state of work pending bit
WORK_STRUCT_PENDING is a mask for testing the pending bit.
test_bit() expects the number of the bit and we need to
use WORK_STRUCT_PENDING_BIT there.

Also work_data_bits() is defined in workqueues.h now.

I have noticed this just by chance when looking how
WORK_STRUCT_PENDING_BIT is used. The change is compile
tested.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-11-06 15:06:05 +01:00
Linus Torvalds e0700ce709 - Revert a dm-multipath change that caused a regression for unprivledged
users (e.g. kvm guests) that issued ioctls when a multipath device had
   no available paths.
 
 - Include Christoph's refactoring of DM's ioctl handling and add support
   for passing through persistent reservations with DM multipath.
 
 - All other changes are very simple cleanups.
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Merge tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:
 "Smaller set of DM changes for this merge.  I've based these changes on
  Jens' for-4.4/reservations branch because the associated DM changes
  required it.

   - Revert a dm-multipath change that caused a regression for
     unprivledged users (e.g. kvm guests) that issued ioctls when a
     multipath device had no available paths.

   - Include Christoph's refactoring of DM's ioctl handling and add
     support for passing through persistent reservations with DM
     multipath.

   - All other changes are very simple cleanups"

* tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm switch: simplify conditional in alloc_region_table()
  dm delay: document that offsets are specified in sectors
  dm delay: capitalize the start of an delay_ctr() error message
  dm delay: Use DM_MAPIO macros instead of open-coded equivalents
  dm linear: remove redundant target name from error messages
  dm persistent data: eliminate unnecessary return values
  dm: eliminate unused "bioset" process for each bio-based DM device
  dm: convert ffs to __ffs
  dm: drop NULL test before kmem_cache_destroy() and mempool_destroy()
  dm: add support for passing through persistent reservations
  dm: refactor ioctl handling
  Revert "dm mpath: fix stalls when handling invalid ioctls"
  dm: initialize non-blk-mq queue data before queue is used
2015-11-04 21:19:53 -08:00
Linus Torvalds ac322de6bf md updates for 4.4.
Two major components to this update.
 
 1/ the clustered-raid1 support from SUSE is nearly
   complete.  There are a few outstanding issues being
   worked on.  Maybe half a dozen patches will bring
   this to a usable state.
 
 2/ The first stage of journalled-raid5 support from
    Facebook makes an appearance.  With a journal
    device configured (typically NVRAM or SSD), the
    "RAID5 write hole" should be closed - a crash
    during degraded operations cannot result in data
    corruption.
 
    The next stage will be to use the journal as a
    write-behind cache so that latency can be reduced
    and in some cases throughput increased by
    performing more full-stripe writes.
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Merge tag 'md/4.4' of git://neil.brown.name/md

Pull md updates from Neil Brown:
 "Two major components to this update.

   1) The clustered-raid1 support from SUSE is nearly complete.  There
      are a few outstanding issues being worked on.  Maybe half a dozen
      patches will bring this to a usable state.

   2) The first stage of journalled-raid5 support from Facebook makes an
      appearance.  With a journal device configured (typically NVRAM or
      SSD), the "RAID5 write hole" should be closed - a crash during
      degraded operations cannot result in data corruption.

      The next stage will be to use the journal as a write-behind cache
      so that latency can be reduced and in some cases throughput
      increased by performing more full-stripe writes.

* tag 'md/4.4' of git://neil.brown.name/md: (66 commits)
  MD: when RAID journal is missing/faulty, block RESTART_ARRAY_RW
  MD: set journal disk ->raid_disk
  MD: kick out journal disk if it's not fresh
  raid5-cache: start raid5 readonly if journal is missing
  MD: add new bit to indicate raid array with journal
  raid5-cache: IO error handling
  raid5: journal disk can't be removed
  raid5-cache: add trim support for log
  MD: fix info output for journal disk
  raid5-cache: use bio chaining
  raid5-cache: small log->seq cleanup
  raid5-cache: new helper: r5_reserve_log_entry
  raid5-cache: inline r5l_alloc_io_unit into r5l_new_meta
  raid5-cache: take rdev->data_offset into account early on
  raid5-cache: refactor bio allocation
  raid5-cache: clean up r5l_get_meta
  raid5-cache: simplify state machine when caches flushes are not needed
  raid5-cache: factor out a helper to run all stripes for an I/O unit
  raid5-cache: rename flushed_ios to finished_ios
  raid5-cache: free I/O units earlier
  ...
2015-11-04 21:12:47 -08:00
Linus Torvalds 527d1529e3 Merge branch 'for-4.4/integrity' of git://git.kernel.dk/linux-block
Pull block integrity updates from Jens Axboe:
 ""This is the joint work of Dan and Martin, cleaning up and improving
  the support for block data integrity"

* 'for-4.4/integrity' of git://git.kernel.dk/linux-block:
  block, libnvdimm, nvme: provide a built-in blk_integrity nop profile
  block: blk_flush_integrity() for bio-based drivers
  block: move blk_integrity to request_queue
  block: generic request_queue reference counting
  nvme: suspend i/o during runtime blk_integrity_unregister
  md: suspend i/o during runtime blk_integrity_unregister
  md, dm, scsi, nvme, libnvdimm: drop blk_integrity_unregister() at shutdown
  block: Inline blk_integrity in struct gendisk
  block: Export integrity data interval size in sysfs
  block: Reduce the size of struct blk_integrity
  block: Consolidate static integrity profile properties
  block: Move integrity kobject to struct gendisk
2015-11-04 20:51:48 -08:00
Linus Torvalds af7eba0158 two more bug fixes for md.
One bugfix for a list corruption in raid5 because of incorrect
 locking.
 
 Other for possible data corruption when a recovering device is failed,
 removed, and re-added.
 
 Both tagged for -stable.
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Merge tag 'md/4.3-rc7-fixes' of git://neil.brown.name/md

Pull md bug fixes from Neil Brown:
 "Two more bug fixes for md.

  One bugfix for a list corruption in raid5 because of incorrect
  locking.

  Other for possible data corruption when a recovering device is failed,
  removed, and re-added.

  Both tagged for -stable"

* tag 'md/4.3-rc7-fixes' of git://neil.brown.name/md:
  Revert "md: allow a partially recovered device to be hot-added to an array."
  md/raid5: fix locking in handle_stripe_clean_event()
2015-10-31 21:20:49 -07:00
Song Liu 339421def5 MD: when RAID journal is missing/faulty, block RESTART_ARRAY_RW
When RAID-4/5/6 array suffers from missing journal device, we put
the array in read only state. We should not allow trasition to
read-write states (clean and active) before replacing journal device.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Shaohua Li f2076e7d06 MD: set journal disk ->raid_disk
Set journal disk ->raid_disk to >=0, I choose raid_disks + 1 instead of
0, because we already have a disk with ->raid_disk 0 and this causes
sysfs entry creation conflict. A lot of places assumes disk with
->raid_disk >=0 is normal raid disk, so we add check for journal disk.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Song Liu a3dfbdaadb MD: kick out journal disk if it's not fresh
When journal disk is faulty and we are reassemabling the raid array, the
journal disk is old. We don't allow the journal disk added to the raid
array. Since journal disk is missing in the array, the raid5 will mark
the array readonly.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Shaohua Li 7dde2ad3c5 raid5-cache: start raid5 readonly if journal is missing
If raid array is expected to have journal (eg, journal is set in MD
superblock feature map) and the array is started without journal disk,
start the array readonly.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Song Liu a97b789644 MD: add new bit to indicate raid array with journal
If a raid array has journal feature bit set, add a new bit to indicate
this. If the array is started without journal disk existing, we know
there is something wrong.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Shaohua Li 6e74a9cfb5 raid5-cache: IO error handling
There are 3 places the raid5-cache dispatches IO. The discard IO error
doesn't matter, so we ignore it. The superblock write IO error can be
handled in MD core. The remaining are log write and flush. When the IO
error happens, we mark log disk faulty and fail all write IO. Read IO is
still allowed to run. Userspace will get a notification too and
corresponding daemon can choose setting raid array readonly for example.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Shaohua Li c2bb6242ec raid5: journal disk can't be removed
raid5-cache uses journal disk rdev->bdev, rdev->mddev in several places.
Don't allow journal disk disappear magically. On the other hand, we do
need to update superblock for other disks to bump up ->events, so next
time journal disk will be identified as stale.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Shaohua Li 4b482044d2 raid5-cache: add trim support for log
Since superblock is updated infrequently, we do a simple trim of log
disk (a synchronous trim)

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Shaohua Li 9efdca16e0 MD: fix info output for journal disk
journal disk can be faulty. The Journal and Faulty aren't exclusive with
each other.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:29 +11:00
Christoph Hellwig 6143e2cecb raid5-cache: use bio chaining
Simplify the bio completion handler by using bio chaining and submitting
bios as soon as they are full.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig 2b8ef16ec4 raid5-cache: small log->seq cleanup
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig c1b9919849 raid5-cache: new helper: r5_reserve_log_entry
Factor out code to reserve log space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig 51039cd066 raid5-cache: inline r5l_alloc_io_unit into r5l_new_meta
This is the only user, and keeping all code initializing the io_unit
structure together improves readbility.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig 1e932a37cc raid5-cache: take rdev->data_offset into account early on
Set up bi_sector properly when we allocate an bio instead of updating it
at submission time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig b349feb36c raid5-cache: refactor bio allocation
Split out a helper to allocate a bio for log writes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig 22581f58ed raid5-cache: clean up r5l_get_meta
Remove the only partially used local 'io' variable to simplify the code
flow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig 56fef7c6e0 raid5-cache: simplify state machine when caches flushes are not needed
For devices without a volatile write cache we don't need to send a FLUSH
command to ensure writes are stable on disk, and thus can avoid the whole
step of batching up bios for processing by the MD thread.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:28 +11:00
Christoph Hellwig d8858f4321 raid5-cache: factor out a helper to run all stripes for an I/O unit
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:27 +11:00
Christoph Hellwig 04732f741d raid5-cache: rename flushed_ios to finished_ios
After this series we won't nessecarily have flushed the cache for these
I/Os, so give the list a more neutral name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:27 +11:00
Christoph Hellwig 170364619a raid5-cache: free I/O units earlier
There is no good reason to keep the I/O unit structures around after the
stripe has been written back to the RAID array.  The only information
we need is the log sequence number, and the checkpoint offset of the
highest successfull writeback.  Store those in the log structure, and
free the IO units from __r5l_stripe_write_finished.

Besides simplifying the code this also avoid having to keep the allocation
for the I/O unit around for a potentially long time as superblock updates
that checkpoint the log do not happen very often.

This also fixes the previously incorrect calculation of 'free' in
r5l_do_reclaim as a side effect: previous if took the last unit which
isn't checkpointed into account.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:27 +11:00
Shaohua Li e6c033f79a raid5-cache: move reclaim stop to quiesce
Move reclaim stop to quiesce handling, where is safer for this stuff.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:27 +11:00
Shaohua Li ac6096e9d5 md: show journal for journal disk in disk state sysfs
Journal disk state sysfs entry should indicate it's journal

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:27 +11:00
Song Liu 0b020e85bd skip match_mddev_units check for special roles
match_mddev_units is used to check whether 2 RAID arrays share
same disk(s). Arrays that share disk(s) will not do resync at the
same time for better performance (fewer HDD seek). However, this
check should not apply to Spare, Faulty, and Journal disks, as
they do not paticipate in resync.

In this patch, match_mddev_units skips check for disks with flag
"Faulty" or "Journal" or raid_disk < 0.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:27 +11:00
Shaohua Li 253f9fd41a raid5-cache: don't delay stripe captured in log
There is a case a stripe gets delayed forever.
1. a stripe finishes construction
2. a new bio hits the stripe
3. handle_stripe runs for the stripe. The stripe gets DELAYED bit set
since construction can't run for new bio (the stripe is locked since
step 1)

Without log, handle_stripe will call ops_run_io. After IO finishes, the
stripe gets unlocked and the stripe will restart and run construction
for the new bio. With log, ops_run_io need to run two times. If the
DELAYED bit set, the stripe can't enter into the handle_list, so the
second ops_run_io doesn't run, which leaves the stripe stalled.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:27 +11:00
Shaohua Li 85f2f9a4f4 raid5-cache: check stripe finish out of order
stripes could finish out of order. Hence r5l_move_io_unit_list() of
__r5l_stripe_write_finished might not move any entry and leave
stripe_end_ios list empty.

This applies on top of http://marc.info/?l=linux-raid&m=144122700510667

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li bd18f6462f md: skip resync for raid array with journal
If a raid array has journal, the journal can guarantee the consistency,
we can skip resync after a unclean shutdown. The exception is raid
creation or user initiated resync, which we still do a raid resync.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li 828cbe989e raid5-cache: optimize FLUSH IO with log enabled
With log enabled, bio is written to raid disks after the bio is settled
down in log disk. The recovery guarantees we can recovery the bio data
from log disk, so we we skip FLUSH IO.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Christoph Hellwig 509ffec708 raid5-cache: move functionality out of __r5l_set_io_unit_state
Just keep __r5l_set_io_unit_state as a small set the state wrapper, and
remove r5l_set_io_unit_state entirely after moving the real
functionality to the two callers that need it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li 0fd22b45b2 raid5-cache: fix a user-after-free bug
r5l_compress_stripe_end_list() can free an io_unit. This breaks the
assumption only reclaimer can free io_unit. We can add a reference count
based io_unit free, but since only reclaim can wait io_unit becoming to
STRIPE_END state, we use a simple global wait queue here.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li a8c34f9159 raid5-cache: switching to state machine for log disk cache flush
Before we write stripe data to raid disks, we must guarantee stripe data
is settled down in log disk. To do this, we flush log disk cache and
wait the flush finish. That wait introduces sleep time in raid5d thread
and impact performance. This patch moves the log disk cache flush
process to the stripe handling state machine, which can remove the wait
in raid5d.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li 5c7e81c3de raid5: enable log for raid array with cache disk
Now log is safe to enable for raid array with cache disk

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li 713cf5a639 raid5: don't allow resize/reshape with cache(log) support
If cache(log) support is enabled, don't allow resize/reshape in current
stage. In the future, we can flush all data from cache(log) to raid
before resize/reshape and then allow resize/reshape.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li 9c3e333d3f raid5: disable batch with log enabled
With log enabled, r5l_write_stripe will add the stripe to log. With
batch, several stripes are linked together. The stripes must be in the
same state. While with log, the log/reclaim unit is stripe, we can't
guarantee the several stripes are in the same state. Disabling batch for
log now.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-11-01 13:48:26 +11:00
Shaohua Li 5cb2fbd6ea raid5-cache: use crc32c checksum
crc32c has lower overhead with cpu acceleration. It's a shame I didn't
use it in first post, sorry. This changes disk format, but we are still
ok in current stage.

V2: delete unnecessary type conversion as pointed out by Bart

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
2015-11-01 13:45:39 +11:00
Tomohiro Kusumi aad9ae4550 dm switch: simplify conditional in alloc_region_table()
The variable sctx->nr_regions has type unsigned long and the variable
nr_regions has type sector_t.

Thus the variables may be different when overflow happens.
Changed the conditional to "if (nr_regions >= ULONG_MAX)".
Also move the assignment of nr_regions after sector_div()
and the sanity check which looks more sane.

Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:06 -04:00
Tomohiro Kusumi f49e869a61 dm delay: document that offsets are specified in sectors
Only delay params are mentioned in delay.txt.
Mention offsets just like documents for linear and flakey do.

Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:05 -04:00
Tomohiro Kusumi e213f33e4d dm delay: capitalize the start of an delay_ctr() error message
All other error messages start capitalized.

Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:04 -04:00
Tomohiro Kusumi 340c9ec09b dm delay: Use DM_MAPIO macros instead of open-coded equivalents
.map function of dm-delay returns return value of delay_bio(),
hence it's supposed to return using a defined DM_MAPIO macro.

Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Acked-By: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:04 -04:00
Tomohiro Kusumi 00272c854e dm linear: remove redundant target name from error messages
Commit 72d94861 back in 2006 should have consistently removed
"dm-linear: " from all error messages.

Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:03 -04:00
Mikulas Patocka 4c7da06f5a dm persistent data: eliminate unnecessary return values
dm_bm_unlock and dm_tm_unlock return an integer value but the returned
value is always 0.  The calling code sometimes checks the return value
and sometimes doesn't.

Eliminate these unnecessary return values and also the checks for them.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:02 -04:00
Mikulas Patocka dbba42d8a9 dm: eliminate unused "bioset" process for each bio-based DM device
Commit 54efd50bfd ("block: make
generic_make_request handle arbitrarily sized bios") makes it possible
for block devices to process large bios.  In doing so that commit
allocates a new queue->bio_split bioset for each block device, this
bioset is used for allocating bios when the driver needs to split large
bios.

Each bioset allocates a workqueue process, thus the above commit
increases the number of processes allocated per block device.

DM doesn't need the queue->bio_split bioset, thus we can deallocate it.
This reduces the number of allocated processes per bio-based DM device
from 3 to 2.  Also remove the call to blk_queue_split(), it is not
needed because DM does its own splitting.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:02 -04:00
Mikulas Patocka a3d939ae7b dm: convert ffs to __ffs
ffs counts bit starting with 1 (for the least significant bit), __ffs
counts bits starting with 0. This patch changes various occurrences of ffs
to __ffs and removes subtraction of 1 from the result.

Note that __ffs (unlike ffs) is not defined when called with zero
argument, but it is not called with zero argument in any of these cases.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:01 -04:00
Julia Lawall 6f65985e26 dm: drop NULL test before kmem_cache_destroy() and mempool_destroy()
Remove DM's unneeded NULL tests before calling these destroy functions,
now that they check for NULL, thanks to these v4.3 commits:
3942d2991 ("mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()")
4e3ca3e03 ("mm/mempool: allow NULL `pool' pointer in mempool_destroy()")

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression x; @@
-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:00 -04:00
Christoph Hellwig 71cdb6978a dm: add support for passing through persistent reservations
This adds support to pass through persistent reservation requests
similar to the existing ioctl handling, and with the same limitations,
e.g. devices may only have a single target attached.

This is mostly intended for multipathing.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:05:59 -04:00
Christoph Hellwig e56f81e0b0 dm: refactor ioctl handling
This moves the call to blkdev_ioctl and the argument checking to DM core
code, and only leaves a callout to find the block device to operate on
in the targets.  This simplifies the code and allows us to pass through
ioctl-like command using other methods in the next patch.

Also split out a helper around calling the prepare_ioctl method that
will be reused for persistent reservation handling.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:05:59 -04:00
Mauricio Faria de Oliveira 47796938c4 Revert "dm mpath: fix stalls when handling invalid ioctls"
This reverts commit a1989b3300.

That commit introduced a regression at least for the case of the SG_IO ioctl()
running without CAP_SYS_RAWIO capability (e.g., unprivileged users) when there
are no active paths: the ioctl() fails with the ENOTTY errno immediately rather
than blocking due to queue_if_no_path until a path becomes active, for example.

That case happens to be exercised by QEMU KVM guests with 'scsi-block' devices
(qemu "-device scsi-block" [1], libvirt "<disk type='block' device='lun'>" [2])
from multipath devices; which leads to SCSI/filesystem errors in such a guest.

More general scenarios can hit that regression too. The following demonstration
employs a SG_IO ioctl() with a standard SCSI INQUIRY command for this objective
(some output & user changes omitted for brevity and comments added for clarity).

Reverting that commit restores normal operation (queueing) in failing scenarios;
tested on linux-next (next-20151022).

1) Test-case is based on sg_simple0 [3] (just SG_IO; remove SG_GET_VERSION_NUM)

    $ cat sg_simple0.c
    ... see [3] ...
    $ sed '/SG_GET_VERSION_NUM/,/}/d' sg_simple0.c > sgio_inquiry.c
    $ gcc sgio_inquiry.c -o sgio_inquiry

2) The ioctl() works fine with active paths present.

    # multipath -l 85ag56
    85ag56 (...) dm-19 IBM     ,2145
    size=60G features='1 queue_if_no_path' hwhandler='0' wp=rw
    |-+- policy='service-time 0' prio=0 status=active
    | |- 8:0:11:0  sdz  65:144  active undef running
    | `- 9:0:9:0   sdbf 67:144  active undef running
    `-+- policy='service-time 0' prio=0 status=enabled
      |- 8:0:12:0  sdae 65:224  active undef running
      `- 9:0:12:0  sdbo 68:32   active undef running

    $ ./sgio_inquiry /dev/mapper/85ag56
    Some of the INQUIRY command's response:
        IBM       2145              0000
    INQUIRY duration=0 millisecs, resid=0

3) The ioctl() fails with ENOTTY errno with _no_ active paths present,
   for unprivileged users (rather than blocking due to queue_if_no_path).

    # for path in $(multipath -l 85ag56 | grep -o 'sd[a-z]\+'); \
          do multipathd -k"fail path $path"; done

    # multipath -l 85ag56
    85ag56 (...) dm-19 IBM     ,2145
    size=60G features='1 queue_if_no_path' hwhandler='0' wp=rw
    |-+- policy='service-time 0' prio=0 status=enabled
    | |- 8:0:11:0  sdz  65:144  failed undef running
    | `- 9:0:9:0   sdbf 67:144  failed undef running
    `-+- policy='service-time 0' prio=0 status=enabled
      |- 8:0:12:0  sdae 65:224  failed undef running
      `- 9:0:12:0  sdbo 68:32   failed undef running

    $ ./sgio_inquiry /dev/mapper/85ag56
    sg_simple0: Inquiry SG_IO ioctl error: Inappropriate ioctl for device

4) dmesg shows that scsi_verify_blk_ioctl() failed for SG_IO (0x2285);
   it returns -ENOIOCTLCMD, later replaced with -ENOTTY in vfs_ioctl().

    $ dmesg
    <...>
    [] device-mapper: multipath: Failing path 65:144.
    [] device-mapper: multipath: Failing path 67:144.
    [] device-mapper: multipath: Failing path 65:224.
    [] device-mapper: multipath: Failing path 68:32.
    [] sgio_inquiry: sending ioctl 2285 to a partition!

5) The ioctl() only works if the SYS_CAP_RAWIO capability is present
   (then queueing happens -- in this example, queue_if_no_path is set);
   this is due to a conditional check in scsi_verify_blk_ioctl().

    # capsh --drop=cap_sys_rawio -- -c './sgio_inquiry /dev/mapper/85ag56'
    sg_simple0: Inquiry SG_IO ioctl error: Inappropriate ioctl for device

    # ./sgio_inquiry /dev/mapper/85ag56 &
    [1] 72830

    # cat /proc/72830/stack
    [<c00000171c0df700>] 0xc00000171c0df700
    [<c000000000015934>] __switch_to+0x204/0x350
    [<c000000000152d4c>] msleep+0x5c/0x80
    [<c00000000077dfb0>] dm_blk_ioctl+0x70/0x170
    [<c000000000487c40>] blkdev_ioctl+0x2b0/0x9b0
    [<c0000000003128e4>] block_ioctl+0x64/0xd0
    [<c0000000002dd3b0>] do_vfs_ioctl+0x490/0x780
    [<c0000000002dd774>] SyS_ioctl+0xd4/0xf0
    [<c000000000009358>] system_call+0x38/0xd0

6) This is the function call chain exercised in this analysis:

SYSCALL_DEFINE3(ioctl, <...>) @ fs/ioctl.c
    -> do_vfs_ioctl()
        -> vfs_ioctl()
            ...
            error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
            ...
                -> dm_blk_ioctl() @ drivers/md/dm.c
                    -> multipath_ioctl() @ drivers/md/dm-mpath.c
                        ...
                        (bdev = NULL, due to no active paths)
                        ...
                        if (!bdev || <...>) {
                            int err = scsi_verify_blk_ioctl(NULL, cmd);
                            if (err)
                                r = err;
                        }
                        ...
                            -> scsi_verify_blk_ioctl() @ block/scsi_ioctl.c
                                ...
                                if (bd && bd == bd->bd_contains) // not taken (bd = NULL)
                                    return 0;
                                ...
                                if (capable(CAP_SYS_RAWIO)) // not taken (unprivileged user)
                                    return 0;
                                ...
                                printk_ratelimited(KERN_WARNING
                                           "%s: sending ioctl %x to a partition!\n" <...>);

                                return -ENOIOCTLCMD;
                            <-
                        ...
                        return r ? : <...>
                    <-
            ...
            if (error == -ENOIOCTLCMD)
                error = -ENOTTY;
             out:
                return error;
            ...

Links:
[1] http://git.qemu.org/?p=qemu.git;a=commit;h=336a6915bc7089fb20fea4ba99972ad9a97c5f52
[2] https://libvirt.org/formatdomain.html#elementsDisks (see 'disk' -> 'device')
[3] http://tldp.org/HOWTO/SCSI-Generic-HOWTO/pexample.html (Revision 1.2, 2002-05-03)

Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-10-31 18:53:51 -04:00
NeilBrown d01552a76d Revert "md: allow a partially recovered device to be hot-added to an array."
This reverts commit 7eb418851f.

This commit is poorly justified, I can find not discusison in email,
and it clearly causes a problem.

If a device which is being recovered fails and is subsequently
re-added to an array, there could easily have been changes to the
array *before* the point where the recovery was up to.  So the
recovery must start again from the beginning.

If a spare is being recovered and fails, then when it is re-added we
really should do a bitmap-based recovery up to the recovery-offset,
and then a full recovery from there.  Before this reversion, we only
did the "full recovery from there" which is not corect.  After this
reversion with will do a full recovery from the start, which is safer
but not ideal.

It will be left to a future patch to arrange the two different styles
of recovery.

Reported-and-tested-by: Nate Dailey <nate.dailey@stratus.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: stable@vger.kernel.org (3.14+)
Fixes: 7eb418851f ("md: allow a partially recovered device to be hot-added to an array.")
2015-10-31 11:00:56 +11:00
Roman Gushchin b8a9d66d04 md/raid5: fix locking in handle_stripe_clean_event()
After commit 566c09c534 ("raid5: relieve lock contention in get_active_stripe()")
__find_stripe() is called under conf->hash_locks + hash.
But handle_stripe_clean_event() calls remove_hash() under
conf->device_lock.

Under some cirscumstances the hash chain can be circuited,
and we get an infinite loop with disabled interrupts and locked hash
lock in __find_stripe(). This leads to hard lockup on multiple CPUs
and following system crash.

I was able to reproduce this behavior on raid6 over 6 ssd disks.
The devices_handle_discard_safely option should be set to enable trim
support. The following script was used:

for i in `seq 1 32`; do
    dd if=/dev/zero of=large$i bs=10M count=100 &
done

neilb: original was against a 3.x kernel.  I forward-ported
  to 4.3-rc.  This verison is suitable for any kernel since
  Commit: 59fc630b8b ("RAID5: batch adjacent full stripe write")
  (v4.1+).  I'll post a version for earlier kernels to stable.

Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Fixes: 566c09c534 ("raid5: relieve lock contention in get_active_stripe()")
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: <stable@vger.kernel.org> # 3.13 - 4.2
2015-10-31 10:53:50 +11:00
Mikulas Patocka ad5f498f61 dm: initialize non-blk-mq queue data before queue is used
Commit bfebd1cdb4 ("dm: add full blk-mq
support to request-based DM") moves the initialization of the fields
backing_dev_info.congested_fn, backing_dev_info.congested_data and
queuedata from the function dm_init_md_queue (that is called when the
device is created) to dm_init_old_md_queue (that is called after the
device type is determined).

There is no locking when accessing these variables, thus it is possible
for other parts of the kernel to briefly see this data in a transient
state (e.g. queue->backing_dev_info.congested_fn initialized and
md->queue->backing_dev_info.congested_data uninitialized, resulting in
passing an incorrect parameter to the function dm_any_congested).

This queue data is left initialized for blk-mq devices even though they
that don't use it.

Fixes: bfebd1cdb4 ("dm: add full blk-mq support to request-based DM")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v4.1+
2015-10-29 22:09:40 -04:00
Linus Torvalds ce6f988603 Some raid1/raid10 fixes.
Two fixes for bugs that are in both raid1 and raid10.
 Both related to bad-block-lists and at least one needs
 to be back ported to 3.1.
 
 Also a revision for the "new" layout in raid10.
 This "new" code (which aims to improve robustness) actually
 reduces robustness in some cases.
 It probably isn't in use at all as not public user-space code
 makes use of these new layouts.
 However just in case someone has their own code, it would be
 good to get the WARNing out for them sooner.
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Merge tag 'md/4.3-rc6-fixes' of git://neil.brown.name/md

Pull md fixes from Neil Brown:
 "Some raid1/raid10 fixes.

  I meant to get this to you before -rc7, but what with all the travel
  plans..

  Two fixes for bugs that are in both raid1 and raid10.  Both related to
  bad-block-lists and at least one needs to be back ported to 3.1.

  Also a revision for the "new" layout in raid10.  This "new" code
  (which aims to improve robustness) actually reduces robustness in some
  cases.  It probably isn't in use at all as not public user-space code
  makes use of these new layouts.  However just in case someone has
  their own code, it would be good to get the WARNing out for them
  sooner"

* tag 'md/4.3-rc6-fixes' of git://neil.brown.name/md:
  md/raid10: fix the 'new' raid10 layout to work correctly.
  md/raid10: don't clear bitmap bit when bad-block-list write fails.
  md/raid1: don't clear bitmap bit when bad-block-list write fails.
  md/raid10: submit_bio_wait() returns 0 on success
  md/raid1: submit_bio_wait() returns 0 on success
2015-10-27 07:41:48 +09:00
Shaohua Li 355810d12a raid5: log recovery
This is the log recovery support. The process is quite straightforward.
We scan the log and read all valid meta/data/parity into memory. If a
stripe's data/parity checksum is correct, the stripe will be recoveried.
Otherwise, it's discarded and we don't scan the log further. The reclaim
process guarantees stripe which starts to be flushed raid disks has
completed data/parity and has correct checksum. To recovery a stripe, we
just copy its data/parity to corresponding raid disks.

The trick thing is superblock update after recovery. we can't let
superblock point to last valid meta block. The log might look like:
| meta 1| meta 2| meta 3|
meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If superblock
points to meta 1, we write a new valid meta 2n.  If crash happens again,
new recovery will start from meta 1. Since meta 2n is valid, recovery
will think meta 3 is valid, which is wrong.  The solution is we create a
new meta in meta2 with its seq == meta 1's seq + 10 and let superblock
points to meta2.  recovery will not think meta 3 is a valid meta,
because its seq is wrong

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-24 17:16:19 +11:00
Shaohua Li 0576b1c618 raid5: log reclaim support
This is the reclaim support for raid5 log. A stripe write will have
following steps:

1. reconstruct the stripe, read data/calculate parity. ops_run_io
prepares to write data/parity to raid disks
2. hijack ops_run_io. stripe data/parity is appending to log disk
3. flush log disk cache
4. ops_run_io run again and do normal operation. stripe data/parity is
written in raid array disks. raid core can return io to upper layer.
5. flush cache of all raid array disks
6. update super block
7. log disk space used by the stripe can be reused

In practice, several stripes consist of an io_unit and we will batch
several io_unit in different steps, but the whole process doesn't
change.

It's possible io return just after data/parity hit log disk, but then
read IO will need read from log disk. For simplicity, IO return happens
at step 4, where read IO can directly read from raid disks.

Currently reclaim run if there is specific reclaimable space (1/4 disk
size or 10G) or we are out of space. Reclaim is just to free log disk
spaces, it doesn't impact data consistency. The size based force reclaim
is to make sure log isn't too big, so recovery doesn't scan log too
much.

Recovery make sure raid disks and log disk have the same data of a
stripe. If crash happens before 4, recovery might/might not recovery
stripe's data/parity depending on if data/parity and its checksum
matches. In either case, this doesn't change the syntax of an IO write.
After step 3, stripe is guaranteed recoverable, because stripe's
data/parity is persistent in log disk. In some cases, log disk content
and raid disks content of a stripe are the same, but recovery will still
copy log disk content to raid disks, this doesn't impact data
consistency. space reuse happens after superblock update and cache
flush.

There is one situation we want to avoid. A broken meta in the middle of
a log causes recovery can't find meta at the head of log. If operations
require meta at the head persistent in log, we must make sure meta
before it persistent in log too. The case is stripe data/parity is in
log and we start write stripe to raid disks (before step 4). stripe
data/parity must be persistent in log before we do the write to raid
disks. The solution is we restrictly maintain io_unit list order. In
this case, we only write stripes of an io_unit to raid disks till the
io_unit is the first one whose data/parity is in log.

The io_unit list order is important for other cases too. For example,
some io_unit are reclaimable and others not. They can be mixed in the
list, we shouldn't reuse space of an unreclaimable io_unit.

Includes fixes to problems which were...
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-24 17:16:19 +11:00
Shaohua Li f6bed0ef0a raid5: add basic stripe log
This introduces a simple log for raid5. Data/parity writing to raid
array first writes to the log, then write to raid array disks. If
crash happens, we can recovery data from the log. This can speed up
raid resync and fix write hole issue.

The log structure is pretty simple. Data/meta data is stored in block
unit, which is 4k generally. It has only one type of meta data block.
The meta data block can track 3 types of data, stripe data, stripe
parity and flush block. MD superblock will point to the last valid
meta data block. Each meta data block has checksum/seq number, so
recovery can scan the log correctly. We store a checksum of stripe
data/parity to the metadata block, so meta data and stripe data/parity
can be written to log disk together. otherwise, meta data write must
wait till stripe data/parity is finished.

For stripe data, meta data block will record stripe data sector and
size. Currently the size is always 4k. This meta data record can be made
simpler if we just fix write hole (eg, we can record data of a stripe's
different disks together), but this format can be extended to support
caching in the future, which must record data address/size.

For stripe parity, meta data block will record stripe sector. It's
size should be 4k (for raid5) or 8k (for raid6). We always store p
parity first. This format should work for caching too.

flush block indicates a stripe is in raid array disks. Fixing write
hole doesn't need this type of meta data, it's for caching extension.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-24 17:16:19 +11:00
Shaohua Li b70abcb247 raid5: add a new state for stripe log handling
When a stripe finishes construction, we write the stripe to raid in
ops_run_io normally. With log, we do a bunch of other operations before
the stripe is written to raid. Mainly write the stripe to log disk,
flush disk cache and so on. The operations are still driven by raid5d
and run in the stripe state machine. We introduce a new state for such
stripe (trapped into log). The stripe is in this state from the time it
first enters ops_run_io (finish construction) to the time it is written
to raid. Since we know the state is only for log, we bypass other
check/operation in handle_stripe.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-24 17:16:19 +11:00
Shaohua Li 6d036f7d52 raid5: export some functions
Next several patches use some raid5 functions, rename them with raid5
prefix and export out.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-24 17:16:18 +11:00
Shaohua Li 3069aa8def md: override md superblock recovery_offset for journal device
Journal device stores data in a log structure. We need record the log
start. Here we override md superblock recovery_offset for this purpose.
This field of a journal device is meaningless otherwise.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-24 17:16:18 +11:00