Commit Graph

4554 Commits

Author SHA1 Message Date
Song Liu
2e38a37f23 md/r5cache: disable write back for degraded array
write-back cache in degraded mode introduces corner cases to the array.
Although we try to cover all these corner cases, it is safer to just
disable write-back cache when the array is in degraded mode.

In this patch, we disable writeback cache for degraded mode:
1. On device failure, if the array enters degraded mode, raid5_error()
   will submit async job r5c_disable_writeback_async to disable
   writeback;
2. In r5c_journal_mode_store(), it is invalid to enable writeback in
   degraded mode;
3. In r5c_try_caching_write(), stripes with s->failed>0 will be handled
   in write-through mode.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24 11:26:06 -08:00
Song Liu
07e8336484 md/r5cache: shift complex rmw from read path to write path
Write back cache requires a complex RMW mechanism, where old data is
read into dev->orig_page for prexor, and then xor is done with
dev->page. This logic is already implemented in the write path.

However, current read path is not awared of this requirement. When
the array is optimal, the RMW is not required, as the data are
read from raid disks. However, when the target stripe is degraded,
complex RMW is required to generate right data.

To keep read path as clean as possible, we handle read path by
flushing degraded, in-journal stripes before processing reads to
missing dev.

Specifically, when there is read requests to a degraded stripe
with data in journal, handle_stripe_fill() calls
r5c_make_stripe_write_out() and exits. Then handle_stripe_dirtying()
will do the complex RMW and flush the stripe to RAID disks. After
that, read requests are handled.

There is one more corner case when there is non-overwrite bio for
the missing (or out of sync) dev. handle_stripe_dirtying() will not
be able to process the non-overwrite bios without constructing the
data in handle_stripe_fill(). This is fixed by delaying non-overwrite
bios in handle_stripe_dirtying(). So handle_stripe_fill() works on
these bios after the stripe is flushed to raid disks.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24 11:20:15 -08:00
Song Liu
a85dd7b8df md/r5cache: flush data only stripes in r5l_recovery_log()
For safer operation, all arrays start in write-through mode, which has been
better tested and is more mature. And actually the write-through/write-mode
isn't persistent after array restarted, so we always start array in
write-through mode. However, if recovery found data-only stripes before the
shutdown (from previous write-back mode), it is not safe to start the array in
write-through mode, as write-through mode can not handle stripes with data in
write-back cache. To solve this problem, we flush all data-only stripes in
r5l_recovery_log(). When r5l_recovery_log() returns, the array starts with
empty cache in write-through mode.

This logic is implemented in r5c_recovery_flush_data_only_stripes():

1. enable write back cache
2. flush all stripes
3. wake up conf->mddev->thread
4. wait for all stripes get flushed (reuse wait_for_quiescent)
5. disable write back cache

The wait in 4 will be waked up in release_inactive_stripe_list()
when conf->active_stripes reaches 0.

It is safe to wake up mddev->thread here because all the resource
required for the thread has been initialized.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24 11:20:15 -08:00
Song Liu
ba02684daf md/raid5: move comment of fetch_block to right location
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24 11:20:14 -08:00
Song Liu
86aa1397dd md/r5cache: read data into orig_page for prexor of cached data
With write back cache, we use orig_page to do prexor. This patch
makes sure we read data into orig_page for it.

Flag R5_OrigPageUPTDODATE is added to show whether orig_page
has the latest data from raid disk.

We introduce a helper function uptodate_for_rmw() to simplify
the a couple conditions in handle_stripe_dirtying().

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24 11:20:14 -08:00
Shaohua Li
d46d29f072 md/raid5-cache: delete meaningless code
sector_t is unsigned long, it's never < 0

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24 11:20:13 -08:00
Jes Sorensen
32cd7cbbac md/raid5: Use correct IS_ERR() variation on pointer check
This fixes a build error on certain architectures, such as ppc64.

Fixes: 6995f0b247e("md: takeover should clear unrelated bits")
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-09 13:58:10 -08:00
Shaohua Li
394ed8e474 md: cleanup mddev flag clear for takeover
Commit 6995f0b (md: takeover should clear unrelated bits) clear
unrelated bits, but it's quite fragile. To avoid error in the future,
define a macro for unsupported mddev flags for each raid type and use it
to clear unsupported mddev flags. This should be less error-prone.

Suggested-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05 11:45:18 -08:00
Colin Ian King
99f17890f0 md/r5cache: fix spelling mistake on "recoverying"
Trivial fix to spelling mistake "recoverying" to "recovering" in
pr_dbg message.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05 11:44:39 -08:00
Song Liu
d2250f105f md/r5cache: assign conf->log before r5l_load_log()
r5l_load_log() calls functions that requires a proper conf->log,
for example, r5c_is_writeback(). Therefore, we should set
conf->log before calling r5l_load_log(). If r5l_load_log() fails,
conf->log is set back to NULL.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05 11:44:38 -08:00
Song Liu
3c66abbaaf md/r5cache: simplify handling of sh->log_start in recovery
We only need to update sh->log_start at the end of recovery,
which is r5c_recovery_rewrite_data_only_stripes(), so it is not
necessary to set it before that. In this patch, log_start is
removed from r5c_recovery_alloc_stripe().

After updating all sh->log_start, rewrite_data_only_stripes()
also updates log->next_checkpoints to the last sh->log_start.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05 11:44:38 -08:00
JackieLiu
28ca833ecf md/raid5-cache: removes unnecessary write-through mode judgments
The write-through mode has been returned in front of the function,
do not need to do it again.

Signed-off-by: JackieLiu <liuyun01@kylinos.cn>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05 11:44:37 -08:00
Robert LeBlanc
bb5f1ed70b md/raid10: Refactor raid10_make_request
Refactor raid10_make_request into seperate read and write functions to
clean up the code.

Shaohua: add the recovery check back to read path

Signed-off-by: Robert LeBlanc <robert@leblancnet.us>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-03 08:56:52 -08:00
Robert LeBlanc
3b046a97cb md/raid1: Refactor raid1_make_request
Refactor raid1_make_request to make read and write code in their own
functions to clean up the code.

Signed-off-by: Robert LeBlanc <robert@leblancnet.us>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-03 08:56:52 -08:00
Linus Torvalds
7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Eric Wheeler
b8c0d911ac bcache: partition support: add 16 minors per bcacheN device
Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net>
Tested-by: Wido den Hollander <wido@widodh.nl>
2016-12-17 13:02:00 -07:00
Kent Overstreet
be628be095 bcache: Make gc wakeup sane, remove set_task_state()
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2016-12-17 13:01:55 -07:00
Michael S. Tsirkin
9efeccacd3 linux: drop __bitwise__ everywhere
__bitwise__ used to mean "yes, please enable sparse checks
unconditionally", but now that we dropped __CHECK_ENDIAN__
__bitwise is exactly the same.
There aren't many users, replace it by __bitwise everywhere.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Stefan Schmidt <stefan@osg.samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Akced-by: Lee Duncan <lduncan@suse.com>
2016-12-16 00:13:41 +02:00
Linus Torvalds
775a2e29c3 . various fixes and improvements to request-based DM and DM multipath
. some locking improvements in DM bufio
 
 . add Kconfig option to disable the DM block manager's extra locking
   which mainly serves as a developer tool
 
 . a few bug fixes to DM's persistent-data
 
 . a couple changes to prepare for multipage biovec support in the block
   layer
 
 . various improvements and cleanups in the DM core, DM cache, DM raid
   and DM crypt
 
 . add ability to have DM crypt use keys from the kernel key retention
   service
 
 . add a new "error_writes" feature to the DM flakey target, reads are
   left unchanged in this mode
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Merge tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - various fixes and improvements to request-based DM and DM multipath

 - some locking improvements in DM bufio

 - add Kconfig option to disable the DM block manager's extra locking
   which mainly serves as a developer tool

 - a few bug fixes to DM's persistent-data

 - a couple changes to prepare for multipage biovec support in the block
   layer

 - various improvements and cleanups in the DM core, DM cache, DM raid
   and DM crypt

 - add ability to have DM crypt use keys from the kernel key retention
   service

 - add a new "error_writes" feature to the DM flakey target, reads are
   left unchanged in this mode

* tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (40 commits)
  dm flakey: introduce "error_writes" feature
  dm cache policy smq: use hash_32() instead of hash_32_generic()
  dm crypt: reject key strings containing whitespace chars
  dm space map: always set ev if sm_ll_mutate() succeeds
  dm space map metadata: skip useless memcpy in metadata_ll_init_index()
  dm space map metadata: fix 'struct sm_metadata' leak on failed create
  Documentation: dm raid: define data_offset status field
  dm raid: fix discard support regression
  dm raid: don't allow "write behind" with raid4/5/6
  dm mpath: use hw_handler_params if attached hw_handler is same as requested
  dm crypt: add ability to use keys from the kernel key retention service
  dm array: remove a dead assignment in populate_ablock_with_values()
  dm ioctl: use offsetof() instead of open-coding it
  dm rq: simplify use_blk_mq initialization
  dm: use blk_set_queue_dying() in __dm_destroy()
  dm bufio: drop the lock when doing GFP_NOIO allocation
  dm bufio: don't take the lock in dm_bufio_shrink_count
  dm bufio: avoid sleeping while holding the dm_bufio lock
  dm table: simplify dm_table_determine_type()
  dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device
  ...
2016-12-14 11:01:00 -08:00
Shaohua Li
20737738d3 Merge branch 'md-next' into md-linus 2016-12-13 12:40:15 -08:00
Mike Snitzer
ef548c551e dm flakey: introduce "error_writes" feature
Recent dm-flakey fixes, to have reads error out during the "down"
interval, made it so that the previous read behaviour is no longer
available.

It is useful to have reads complete like normal but have writes error
out, so make it possible again with a new "error_writes" feature.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-13 15:01:31 -05:00
Linus Torvalds
36869cb93d Merge branch 'for-4.10/block' of git://git.kernel.dk/linux-block
Pull block layer updates from Jens Axboe:
 "This is the main block pull request this series. Contrary to previous
  release, I've kept the core and driver changes in the same branch. We
  always ended up having dependencies between the two for obvious
  reasons, so makes more sense to keep them together. That said, I'll
  probably try and keep more topical branches going forward, especially
  for cycles that end up being as busy as this one.

  The major parts of this pull request is:

   - Improved support for O_DIRECT on block devices, with a small
     private implementation instead of using the pig that is
     fs/direct-io.c. From Christoph.

   - Request completion tracking in a scalable fashion. This is utilized
     by two components in this pull, the new hybrid polling and the
     writeback queue throttling code.

   - Improved support for polling with O_DIRECT, adding a hybrid mode
     that combines pure polling with an initial sleep. From me.

   - Support for automatic throttling of writeback queues on the block
     side. This uses feedback from the device completion latencies to
     scale the queue on the block side up or down. From me.

   - Support from SMR drives in the block layer and for SD. From Hannes
     and Shaun.

   - Multi-connection support for nbd. From Josef.

   - Cleanup of request and bio flags, so we have a clear split between
     which are bio (or rq) private, and which ones are shared. From
     Christoph.

   - A set of patches from Bart, that improve how we handle queue
     stopping and starting in blk-mq.

   - Support for WRITE_ZEROES from Chaitanya.

   - Lightnvm updates from Javier/Matias.

   - Supoort for FC for the nvme-over-fabrics code. From James Smart.

   - A bunch of fixes from a whole slew of people, too many to name
     here"

* 'for-4.10/block' of git://git.kernel.dk/linux-block: (182 commits)
  blk-stat: fix a few cases of missing batch flushing
  blk-flush: run the queue when inserting blk-mq flush
  elevator: make the rqhash helpers exported
  blk-mq: abstract out blk_mq_dispatch_rq_list() helper
  blk-mq: add blk_mq_start_stopped_hw_queue()
  block: improve handling of the magic discard payload
  blk-wbt: don't throttle discard or write zeroes
  nbd: use dev_err_ratelimited in io path
  nbd: reset the setup task for NBD_CLEAR_SOCK
  nvme-fabrics: Add FC LLDD loopback driver to test FC-NVME
  nvme-fabrics: Add target support for FC transport
  nvme-fabrics: Add host support for FC transport
  nvme-fabrics: Add FC transport LLDD api definitions
  nvme-fabrics: Add FC transport FC-NVME definitions
  nvme-fabrics: Add FC transport error codes to nvme.h
  Add type 0x28 NVME type code to scsi fc headers
  nvme-fabrics: patch target code in prep for FC transport support
  nvme-fabrics: set sqe.command_id in core not transports
  parser: add u64 number parser
  nvme-rdma: align to generic ib_event logging helper
  ...
2016-12-13 10:19:16 -08:00
Shaohua Li
2953079c69 md: separate flags for superblock changes
The mddev->flags are used for different purposes. There are a lot of
places we check/change the flags without masking unrelated flags, we
could check/change unrelated flags. These usage are most for superblock
write, so spearate superblock related flags. This should make the code
clearer and also fix real bugs.

Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-08 22:01:47 -08:00
Shaohua Li
82a301cb0e md: MD_RECOVERY_NEEDED is set for mddev->recovery
Fixes: 90f5f7ad4f38("md: Wait for md_check_recovery before attempting device
removal.")

Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-08 22:00:43 -08:00
Shaohua Li
6995f0b247 md: takeover should clear unrelated bits
When we change level from raid1 to raid5, the MD_FAILFAST_SUPPORTED bit
will be accidentally set, but raid5 doesn't support it. The same is true
for the MD_HAS_JOURNAL bit.

Fix: 46533ff (md: Use REQ_FAILFAST_* on metadata writes where appropriate)
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-08 22:00:11 -08:00
Mike Snitzer
e99dda8fc4 dm cache policy smq: use hash_32() instead of hash_32_generic()
Switch to using hash_32() because hash_32_generic() should only be used
by the kernel's selftests.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 19:42:37 -05:00
Ondrej Kozina
027c431ccf dm crypt: reject key strings containing whitespace chars
Unfortunately key_string may theoretically contain whitespace even after
it's processed by dm_split_args().  The reason for this is DM core
supports escaping of almost all chars including any whitespace.

If userspace passes a key to the kernel in format ":32:logon:my_prefix:my\ key"
dm-crypt will look up key "my_prefix:my key" in kernel keyring service.
So far everything's fine.

Unfortunately if userspace later calls DM_TABLE_STATUS ioctl, it will not
receive back expected ":32:logon:my_prefix:my\ key" but the unescaped version
instead.  Also userpace (most notably cryptsetup) is not ready to parse
single target argument containing (even escaped) whitespace chars and any
whitespace is simply taken as delimiter of another argument.

This effect is mitigated by the fact libdevmapper curently performs
double escaping of '\' char.  Any user input in format "x\ x" is
transformed into "x\\ x" before being passed to the kernel.  Nonetheless
dm-crypt may be used without libdevmapper.  Therefore the near-term
solution to this is to reject any key string containing whitespace.

Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:16 -05:00
Benjamin Marzinski
b446396b74 dm space map: always set ev if sm_ll_mutate() succeeds
If no block was allocated or freed, sm_ll_mutate() wasn't setting
*ev, leaving the variable unitialized. sm_ll_insert(),
sm_disk_inc_block(), and sm_disk_new_block() all check ev to see
if there was an allocation event in sm_ll_mutate(), possibly
reading unitialized data.

If no allocation event occured, sm_ll_mutate() should set *ev
to SM_NONE.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:15 -05:00
Benjamin Marzinski
0c79ce0b75 dm space map metadata: skip useless memcpy in metadata_ll_init_index()
When metadata_ll_init_index() is called by sm_ll_new_metadata(),
ll->mi_le hasn't been initialized yet. So, when
metadata_ll_init_index() copies the contents of ll->mi_le into the
newly allocated bitmap_root, it is just copying garbage. ll->mi_le
will be allocated later in sm_ll_extend() and copied into the
bitmap_root, in sm_ll_commit().

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:15 -05:00
Benjamin Marzinski
314c25c56c dm space map metadata: fix 'struct sm_metadata' leak on failed create
In dm_sm_metadata_create() we temporarily change the dm_space_map
operations from 'ops' (whose .destroy function deallocates the
sm_metadata) to 'bootstrap_ops' (whose .destroy function doesn't).

If dm_sm_metadata_create() fails in sm_ll_new_metadata() or
sm_ll_extend(), it exits back to dm_tm_create_internal(), which calls
dm_sm_destroy() with the intention of freeing the sm_metadata, but it
doesn't (because the dm_space_map operations is still set to
'bootstrap_ops').

Fix this by setting the dm_space_map operations back to 'ops' if
dm_sm_metadata_create() fails when it is set to 'bootstrap_ops'.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2016-12-08 14:13:14 -05:00
Heinz Mauelshagen
11e2968478 dm raid: fix discard support regression
Commit ecbfb9f118 ("dm raid: add raid level takeover support") moved the
configure_discard_support() call from raid_ctr() to raid_preresume().

Enabling/disabling discard _must_ happen during table load (through the
.ctr hook).  Fix this regression by moving the
configure_discard_support() call back to raid_ctr().

Fixes: ecbfb9f118 ("dm raid: add raid level takeover support")
Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:12 -05:00
Heinz Mauelshagen
affa9d28f7 dm raid: don't allow "write behind" with raid4/5/6
Remove CTR_FLAG_MAX_WRITE_BEHIND from raid4/5/6's valid ctr flags.

Only the md raid1 personality supports setting a maximum number
of "write behind" write IOs on any legs set to "write mostly".
"write mostly" enhances throughput with slow links/disks.

Technically the "write behind" value is a write intent bitmap
property only being respected by the raid1 personality.  It allows a
maximum number of "write behind" writes to any "write mostly" raid1
mirror legs to be delayed and avoids reads from such legs.

No other MD personalities supported via dm-raid make use of "write
behind", thus setting this property is superfluous; it wouldn't cause
harm but it is correct to reject it.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:11 -05:00
tang.junhui
54cd640d20 dm mpath: use hw_handler_params if attached hw_handler is same as requested
Let the requested m->hw_handler_params be used if the attached hardware
handler is the same handler as requested with m->hw_handler_name.

Signed-off-by: tang.junhui <tang.junhui@zte.com.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:10 -05:00
Ondrej Kozina
c538f6ec9f dm crypt: add ability to use keys from the kernel key retention service
The kernel key service is a generic way to store keys for the use of
other subsystems. Currently there is no way to use kernel keys in dm-crypt.
This patch aims to fix that. Instead of key userspace may pass a key
description with preceding ':'. So message that constructs encryption
mapping now looks like this:

  <cipher> [<key>|:<key_string>] <iv_offset> <dev_path> <start> [<#opt_params> <opt_params>]

where <key_string> is in format: <key_size>:<key_type>:<key_description>

Currently we only support two elementary key types: 'user' and 'logon'.
Keys may be loaded in dm-crypt either via <key_string> or using
classical method and pass the key in hex representation directly.

dm-crypt device initialised with a key passed in hex representation may be
replaced with key passed in key_string format and vice versa.

(Based on original work by Andrey Ryabinin)

Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:09 -05:00
Bart Van Assche
0637018dff dm array: remove a dead assignment in populate_ablock_with_values()
A value is assigned to 'nr_entries' but is never used, remove it.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:09 -05:00
Bart Van Assche
6080758d44 dm ioctl: use offsetof() instead of open-coding it
Subtracting sizes is a fragile approach because the result is only
correct if the compiler has not added any padding at the end of the
structure. Hence use offsetof() instead of size subtraction. An
additional advantage of offsetof() is that it makes the intent more
clear.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:08 -05:00
Bart Van Assche
b23df0d048 dm rq: simplify use_blk_mq initialization
Use a single statement to declare and initialize 'use_blk_mq' instead
of two statements.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:07 -05:00
Bart Van Assche
2e91c36941 dm: use blk_set_queue_dying() in __dm_destroy()
After QUEUE_FLAG_DYING has been set any code that is waiting in
get_request() should be woken up.  But to get this behaviour
blk_set_queue_dying() must be used instead of only setting
QUEUE_FLAG_DYING.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:06 -05:00
Mikulas Patocka
41c73a49df dm bufio: drop the lock when doing GFP_NOIO allocation
If the first allocation attempt using GFP_NOWAIT fails, drop the lock
and retry using GFP_NOIO allocation (lock is dropped because the
allocation can take some time).

Note that we won't do GFP_NOIO allocation when we loop for the second
time, because the lock shouldn't be dropped between __wait_for_free_buffer
and __get_unclaimed_buffer.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:05 -05:00
Mikulas Patocka
d12067f428 dm bufio: don't take the lock in dm_bufio_shrink_count
dm_bufio_shrink_count() is called from do_shrink_slab to find out how many
freeable objects are there. The reported value doesn't have to be precise,
so we don't need to take the dm-bufio lock.

Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:04 -05:00
Douglas Anderson
9ea61cac0b dm bufio: avoid sleeping while holding the dm_bufio lock
We've seen in-field reports showing _lots_ (18 in one case, 41 in
another) of tasks all sitting there blocked on:

  mutex_lock+0x4c/0x68
  dm_bufio_shrink_count+0x38/0x78
  shrink_slab.part.54.constprop.65+0x100/0x464
  shrink_zone+0xa8/0x198

In the two cases analyzed, we see one task that looks like this:

  Workqueue: kverityd verity_prefetch_io

  __switch_to+0x9c/0xa8
  __schedule+0x440/0x6d8
  schedule+0x94/0xb4
  schedule_timeout+0x204/0x27c
  schedule_timeout_uninterruptible+0x44/0x50
  wait_iff_congested+0x9c/0x1f0
  shrink_inactive_list+0x3a0/0x4cc
  shrink_lruvec+0x418/0x5cc
  shrink_zone+0x88/0x198
  try_to_free_pages+0x51c/0x588
  __alloc_pages_nodemask+0x648/0xa88
  __get_free_pages+0x34/0x7c
  alloc_buffer+0xa4/0x144
  __bufio_new+0x84/0x278
  dm_bufio_prefetch+0x9c/0x154
  verity_prefetch_io+0xe8/0x10c
  process_one_work+0x240/0x424
  worker_thread+0x2fc/0x424
  kthread+0x10c/0x114

...and that looks to be the one holding the mutex.

The problem has been reproduced on fairly easily:
0. Be running Chrome OS w/ verity enabled on the root filesystem
1. Pick test patch: http://crosreview.com/412360
2. Install launchBalloons.sh and balloon.arm from
     http://crbug.com/468342
   ...that's just a memory stress test app.
3. On a 4GB rk3399 machine, run
     nice ./launchBalloons.sh 4 900 100000
   ...that tries to eat 4 * 900 MB of memory and keep accessing.
4. Login to the Chrome web browser and restore many tabs

With that, I've seen printouts like:
  DOUG: long bufio 90758 ms
...and stack trace always show's we're in dm_bufio_prefetch().

The problem is that we try to allocate memory with GFP_NOIO while
we're holding the dm_bufio lock.  Instead we should be using
GFP_NOWAIT.  Using GFP_NOIO can cause us to sleep while holding the
lock and that causes the above problems.

The current behavior explained by David Rientjes:

  It will still try reclaim initially because __GFP_WAIT (or
  __GFP_KSWAPD_RECLAIM) is set by GFP_NOIO.  This is the cause of
  contention on dm_bufio_lock() that the thread holds.  You want to
  pass GFP_NOWAIT instead of GFP_NOIO to alloc_buffer() when holding a
  mutex that can be contended by a concurrent slab shrinker (if
  count_objects didn't use a trylock, this pattern would trivially
  deadlock).

This change significantly increases responsiveness of the system while
in this state.  It makes a real difference because it unblocks kswapd.
In the bug report analyzed, kswapd was hung:

   kswapd0         D ffffffc000204fd8     0    72      2 0x00000000
   Call trace:
   [<ffffffc000204fd8>] __switch_to+0x9c/0xa8
   [<ffffffc00090b794>] __schedule+0x440/0x6d8
   [<ffffffc00090bac0>] schedule+0x94/0xb4
   [<ffffffc00090be44>] schedule_preempt_disabled+0x28/0x44
   [<ffffffc00090d900>] __mutex_lock_slowpath+0x120/0x1ac
   [<ffffffc00090d9d8>] mutex_lock+0x4c/0x68
   [<ffffffc000708e7c>] dm_bufio_shrink_count+0x38/0x78
   [<ffffffc00030b268>] shrink_slab.part.54.constprop.65+0x100/0x464
   [<ffffffc00030dbd8>] shrink_zone+0xa8/0x198
   [<ffffffc00030e578>] balance_pgdat+0x328/0x508
   [<ffffffc00030eb7c>] kswapd+0x424/0x51c
   [<ffffffc00023f06c>] kthread+0x10c/0x114
   [<ffffffc000203dd0>] ret_from_fork+0x10/0x40

By unblocking kswapd memory pressure should be reduced.

Suggested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:04 -05:00
Bart Van Assche
5b8c01f74c dm table: simplify dm_table_determine_type()
Use a single loop instead of two loops to determine whether or not
all_blk_mq has to be set.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:03 -05:00
Bart Van Assche
301fc3f5ef dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device
When dm_table_set_type() is used by a target to establish a DM table's
type (e.g. DM_TYPE_MQ_REQUEST_BASED in the case of DM multipath) the
DM core must go on to verify that the devices in the table are
compatible with the established type.

Fixes: e83068a5 ("dm mpath: add optional "queue_mode" feature")
Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:12:53 -05:00
Mike Snitzer
6936c12cf8 dm table: fix 'all_blk_mq' inconsistency when an empty table is loaded
An earlier DM multipath table could have been build ontop of underlying
devices that were all using blk-mq.  In that case, if that active
multipath table is replaced with an empty DM multipath table (that
reflects all paths have failed) then it is important that the
'all_blk_mq' state of the active table is transfered to the new empty DM
table.  Otherwise dm-rq.c:dm_old_prep_tio() will incorrectly clone a
request that isn't needed by the DM multipath target when it is to issue
IO to an underlying blk-mq device.

Fixes: e83068a5 ("dm mpath: add optional "queue_mode" feature")
Cc: stable@vger.kernel.org # 4.8+
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Tested-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:12:52 -05:00
Song Liu
3c6edc6608 md/r5cache: after recovery, increase journal seq by 10000
Currently, we increase journal entry seq by 10 after recovery.
However, this is not sufficient in the following case.

After crash the journal looks like

| seq+0 | +1 | +2 | +3 | +4 | +5 | +6 | +7 | ... | +11 | +12 |

If +1 is not valid, we dropped all entries from +1 to +12; and
write seq+10:

| seq+0 | +10 | +2 | +3 | +4 | +5 | +6 | +7 | ... | +11 | +12 |

However, if we write a big journal entry with seq+11, it will
connect with some stale journal entry:

| seq+0 | +10 |                     +11                 | +12 |

To reduce the risk of this issue, we increase seq by 10000 instead.

Shaohua: use 10000 instead of 1000. The risk should be very unlikely. The total
stripe cache size is less than 2k typically, and several stripes can fit into
one meta data block. So the total inflight meta data blocks would be quite
small, which means the the total sequence number used should be quite small.
The 10000 sequence number increase should be far more than safe.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-08 10:54:47 -08:00
Song Liu
5c88f403a5 md/raid5-cache: fix crc in rewrite_data_only_stripes()
r5l_recovery_create_empty_meta_block() creates crc for the empty
metablock. After the metablock is updated, we need clear the
checksum before recalculate it.

Shaohua: moved checksum calculation out of
r5l_recovery_create_empty_meta_block. We should calculate it after all fields
are updated.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-08 10:34:03 -08:00
JackieLiu
d30dfeb9be md/raid5-cache: no recovery is required when create super-block
When create the super-block information, We do not need to do this
recovery stage, only need to initialize some variables.

Signed-off-by: JackieLiu <liuyun01@kylinos.cn>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-08 10:01:17 -08:00
NeilBrown
e2342ca832 md: fix refcount problem on mddev when stopping array.
md_open() gets a counted reference on an mddev using mddev_find().
If it ends up returning an error, it must drop this reference.

There are two error paths where the reference is not dropped.
One only happens if the process is signalled and an awkward time,
which is quite unlikely.
The other was introduced recently in commit af8d8e6f0.

Change the code to ensure the drop the reference when returning an error,
and make it harded to re-introduce this sort of bug in the future.

Reported-by: Marc Smith <marc.smith@mcc.edu>
Fixes: af8d8e6f03 ("md: changes for MD_STILL_CLOSED flag")
Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-05 17:11:03 -08:00
Zhengyuan Liu
3d7e7e1d9d md/r5cache: do r5c_update_log_state after log recovery
We should update log state after we did a log recovery, current completion
may get wrong log state since log->log_start wasn't initalized until we
called r5l_recovery_log.

At log recovery stage, no lock needed as there is no race conditon.
next_checkpoint field will be initialized in r5l_recovery_log too.

Signed-off-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-05 17:11:02 -08:00
JackieLiu
43b9674832 md/raid5-cache: adjust the write position of the empty block if no data blocks
When recovery is complete, we write an empty block and record his
position first, then make the data-only stripes rewritten done,
the location of the empty block as the last checkpoint position
to write into the super block. And we should update last_checkpoint
to this empty block position.

------------------------------------------------------------------
|  old log       | empty block | data only stripes | invalid log |
------------------------------------------------------------------
^                ^                                 ^
|                |- log->last_checkpoint           |- log->log_start
|                |- log->last_cp_seq               |- log->next_checkpoint
|- log->seq=n    |- log->seq=10+n

At the same time, if there is no data-only stripes, this scene may appear,
| meta1 | meta2 | meta3 |
meta 1 is valid, meta 2 is invalid. meta 3 could be valid. so we should
The solution is we create a new meta in meta2 with its seq == meta1's
seq + 10 and let superblock points to meta2.

Signed-off-by: JackieLiu <liuyun01@kylinos.cn>
Reviewed-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2016-12-05 17:11:02 -08:00