When doing resync or repair, attempt to correct bad blocks, according
to WriteErrorSeen policy
Signed-off-by: Alex Lyakas <alex.bolshoy@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
'sync' writes set both REQ_SYNC and REQ_NOIDLE.
O_DIRECT writes set REQ_SYNC but not REQ_NOIDLE.
We currently assume that a REQ_SYNC request will not be followed by
more requests and so set STRIPE_PREREAD_ACTIVE to expedite the
request.
This is appropriate for sync requests, but not for O_DIRECT requests.
So make the setting of STRIPE_PREREAD_ACTIVE conditional on REQ_NOIDLE
rather than REQ_SYNC. This is consistent with the documented meaning
of REQ_NOIDLE:
__REQ_NOIDLE, /* don't anticipate more IO after this one */
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
If a resync of a RAID1 array with 2 devices finds a known bad block
one device it will neither read from, or write to, that device for
this block offset.
So there will be one read_target (The other device) and zero write
targets.
This condition causes md/raid1 to abort the resync assuming that it
has finished - without known bad blocks this would be true.
When there are no write targets because of the presence of bad blocks
we should only skip over the area covered by the bad block.
RAID10 already gets this right, raid1 doesn't. Or didn't.
As this can cause a 'sync' to abort early and appear to have succeeded
it could lead to some data corruption, so it suitable for -stable.
Cc: stable@vger.kernel.org
Reported-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
do_md_stop tests mddev->openers while holding ->open_mutex,
and fails if this count is too high.
So callers do not need to check mddev->openers and doing so isn't
very meaningful as they don't hold ->open_mutex so the number could
change.
So remove the unnecessary tests on mddev->openers.
These are not called often enough for there to be any gain in
an early test on ->open_mutex to avoid the need for a slightly more
costly mutex_lock call.
Signed-off-by: NeilBrown <neilb@suse.de>
Because bios will merge at block-layer,so bios-error may caused by other
bio which be merged into to the same request.
Using this flag,it will find exactly error-sector and not do redundant
operation like re-write and re-read.
V0->V1:Using REQ_FLUSH instead REQ_NOMERGE avoid bio merging at block
layer.
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
For SSD, if request size exceeds specific value (optimal io size), request size
isn't important for bandwidth. In such condition, if making request size bigger
will cause some disks idle, the total throughput will actually drop. A good
example is doing a readahead in a two-disk raid1 setup.
So when should we split big requests? We absolutly don't want to split big
request to very small requests. Even in SSD, big request transfer is more
efficient. This patch only considers request with size above optimal io size.
If all disks are busy, is it worth doing a split? Say optimal io size is 16k,
two requests 32k and two disks. We can let each disk run one 32k request, or
split the requests to 4 16k requests and each disk runs two. It's hard to say
which case is better, depending on hardware.
So only consider case where there are idle disks. For readahead, split is
always better in this case. And in my test, below patch can improve > 30%
thoughput. Hmm, not 100%, because disk isn't 100% busy.
Such case can happen not just in readahead, for example, in directio. But I
suppose directio usually will have bigger IO depth and make all disks busy, so
I ignored it.
Note: if the raid uses any hard disk, we don't prevent merging. That will make
performace worse.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
SSD hasn't spindle, distance between requests means nothing. And the original
distance based algorithm sometimes can cause severe performance issue for SSD
raid.
Considering two thread groups, one accesses file A, the other access file B.
The first group will access one disk and the second will access the other disk,
because requests are near from one group and far between groups. In this case,
read balance might keep one disk very busy but the other relative idle. For
SSD, we should try best to distribute requests to as many disks as possible.
There isn't spindle move penality anyway.
With below patch, I can see more than 50% throughput improvement sometimes
depending on workloads.
The only exception is small requests can be merged to a big request which
typically can drive higher throughput for SSD too. Such small requests are
sequential reads. Unlike hard disk, sequential read which can't be merged (for
example direct IO, or read without readahead) can be ignored for SSD. Again
there is no spindle move penality. readahead dispatches small requests and such
requests can be merged.
Last patch can help detect sequential read well, at least if concurrent read
number isn't greater than raid disk number. In that case, distance based
algorithm doesn't work well too.
V2: For hard disk and SSD mixed raid, doesn't use distance based algorithm for
random IO too. This makes the algorithm generic for raid with SSD.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Currently the sequential read detection is global wide. It's natural to make it
per disk based, which can improve the detection for concurrent multiple
sequential reads. And next patch will make SSD read balance not use distance
based algorithm, where this change help detect truly sequential read for SSD.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
md/raid10: Export is_congested test.
In similar fashion to commits
11d8a6e3719519fbc0e2c9d61b6fa931b84bf813
1ed7242e591af7e233234d483f12d33818b189d9
we export the RAID10 congestion checking function so that dm-raid.c can
make use of it and make use of the personality. The 'queue' and 'gendisk'
structures will not be available to the MD code when device-mapper sets
up the device, so we conditionalize access to these fields also.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
MD RAID1/RAID10: Move some macros from .h file to .c file
There are three macros (IO_BLOCKED,IO_MADE_GOOD,BIO_SPECIAL) which are defined
in both raid1.h and raid10.h. They are only used in there respective .c files.
However, if we wish to make RAID10 accessible to the device-mapper RAID
target (dm-raid.c), then we need to move these macros into the .c files where
they are used so that they do not conflict with each other.
The macros from the two files are identical and could be moved into md.h, but
I chose to leave the duplication and have them remain in the personality
files.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
MD RAID1: Rename the structure 'mirror_info' to 'raid1_info'
The same structure name ('mirror_info') is used by raid10. Each of these
structures are defined in there respective header files. If dm-raid is
to support both RAID1 and RAID10, the header files will be included and
the structure names must not collide. While only one of these structure
names needs to change, this patch adds consistency to the naming of the
structure.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
MD RAID10: Rename the structure 'mirror_info' to 'raid10_info'
The same structure name ('mirror_info') is used by raid1. Each of these
structures are defined in there respective header files. If dm-raid is
to support both RAID1 and RAID10, the header files will be included and
the structure names must not collide.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
In preparation for RAID10 inclusion in dm-raid, we move the sectors_per_dev
calculation later in the device creation process. This is because we won't
know up-front how many stripes vs how many mirrors there are which will
change the calculation.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
In preparation for RAID10 addition to dm-raid, we change an 'if' conditional
to a 'switch' conditional to make it easier to see what is being checked for
each RAID type.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
A SCSI device handler might get attached to a device during the
initial device scan. We do not necessarily want to override
this when loading a multipath table, so this patch adds a new
multipath feature argument "retain_attached_hw_handler".
During SCSI device scan all loaded SCSI device handlers will be
consulted for a match (via scsi_dh's provided .match). If a match is
found that device handler will be attached. We need a way to have
userspace multipathd's provided 'hw_handler' not override the already
attached hardware handler.
When specifying the new feature 'retain_attached_hw_handler' multipath
will use the currently attached hardware handler instead of trying to
attach the one specified during table load. If no hardware handler is
attached the specified hardware handler will still be used.
Leverages scsi_dh_attach's ability to increment the scsi_dh's reference
count if the same scsi_dh name is provided when attaching - currently
attached scsi_dh name is determined with scsi_dh_attached_handler_name.
Depends upon commit 7e8a74b177f17d100916b6ad415450f7c9508691
("[SCSI] scsi_dh: add scsi_dh_attached_handler_name").
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Babu Moger <babu.moger@netapp.com>
Reviewed-by: Chandra Seetharaman <sekharan@us.ibm.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm-thin will be most likely used with a block size that is a power of
two. So it should be optimized for this case.
This patch changes division and modulo operations to shifts and bit
masks if block size is a power of two.
A test that bi_sector is divisible by a block size is removed from
io_overlaps_block. Device mapper never sends bios that span a block
boundary. Consequently, if we tested that bi_size is equivalent to block
size, bi_sector must already be on a block boundary.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch sets the variable "ti->split_discard_requests" for the dm thin
target so that device mapper core splits discard requests on a block
boundary.
Consequently, a discard request that spans multiple blocks is never sent
to dm-thin. The patch also removes some code in process_discard that
deals with discards that span multiple blocks.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch introduces a new variable split_discard_requests. It can be
set by targets so that discard requests are split on max_io_len
boundaries.
When split_discard_requests is not set, discard requests are only split on
boundaries between targets, as was the case before this patch.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Non power of 2 blocksize support is needed to properly align thinp IO
on storage that has non power of 2 optimal IO sizes (e.g. RAID6 10+2).
Use sector_div to support non power of 2 blocksize for the pool's
data device. This provides comparable performance to the power of 2
math that was performed until now (as tested on modern x86_64 hardware).
The kernel currently assumes that limits->discard_granularity is a power
of two so the thin target only enables discard support if the block
size is a power of two.
Eliminate pool structure's 'block_shift', 'offset_mask' and
remaining 4 byte holes.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm-stripe is usually used with a chunk size that is a power of two.
Use faster shifts and bit masks in such cases.
stripe_width is already optimized in a similar way.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
There is no technical limitation in device mapper that would prevent the
dm-stripe target from using a stripe size smaller than page size.
This patch removes the limit and makes stripe volumes portable across
architectures with different page size.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Support non-power-of-2 chunk sizes with dm striping for proper alignment
of stripe IO on storage that has non-power-of-2 optimal IO sizes (e.g.
RAID6 10+2).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove the restriction that limits a target's specified maximum incoming
I/O size to be a power of 2.
Rename this setting from 'split_io' to the less-ambiguous 'max_io_len'.
Change it from sector_t to uint32_t, which is plenty big enough, and
introduce a wrapper function dm_set_target_max_io_len() to set it.
Use sector_div() to process it now that it is not necessarily a power of 2.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The structure stripe_c contains a stripes_mask field. This field is
useless because it can be trivially calculated by subtracting one from
stripes. It is used only at one place. This patch removes it.
The patch also changes ffs(stripes) - 1 to __ffs(stripes).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm-stripe is supposed to ensure that all the space allocated to the
stripes is fully used and that all stripes are the same size. This
patch fixes the test. It checks that device length is divisible by the
chunk size and checks that the resulting quotient is divisible by the
number of stripes (which is equivalent to testing if device length is
divisible by chunk_size * stripes).
Previously, the code only tested that the number of sectors in the target
was divisible by each of the chunk size and the number of stripes
separately, which could leave entire stripes unused.
(A setup that genuinely needs some stripes to be shorter than others
can be created by concatenating striped targets.)
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Provide specific error message strings for two pool_ctr() failure cases
that currently give just "Unknown error".
Reference: test_two_pools_pointing_to_the_same_metadata_fails and
test_different_pool_cant_replace_pool in thinp-test-suite.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Introduce THIN_MAX_CONCURRENT_LOCKS into dm-thin-metadata to
give a name to an otherwise "magic" number.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove the pointless label 'out' from __commit_transaction in
dm-thin-metadata.c
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove debug space map checker from dm persistent data.
The space map checker is a wrapper for other space maps that double
checks the reference counts are correct. It holds all these reference
counts in memory rather than on disk, so uses a lot of memory and is
thus restricted to small pools.
As yet, this checker hasn't found any issues, but has caused a few of
its own due to people turning it on by default with larger pools.
Removing.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Clean up "warning: dubious: !x & y". Also make it clear that
__snapshotted_since() returns a bool and that dm_thin_lookup_result's
'shared' member is a flag.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reduce the slab size used for the dm_thin_endio_hook mempool.
Allocation has been seen to fail on machines with smaller amounts
of memory due to fragmentation.
lvm: page allocation failure. order:5, mode:0xd0
device-mapper: table: 253:38: thin-pool: Error creating pool's endio_hook mempool
Cc: stable@vger.kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
- avoid a crash in dm-raid1 when discards coincide with mirror recovery;
- avoid discarding shared data that's still needed in dm-thin;
- don't guarantee that discarded blocks will be wiped in dm-raid1.
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Merge tag 'dm-3.5-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm
Pull device-mapper discard fixes from Alasdair G Kergon:
- avoid a crash in dm-raid1 when discards coincide with mirror
recovery;
- avoid discarding shared data that's still needed in dm-thin;
- don't guarantee that discarded blocks will be wiped in dm-raid1.
* tag 'dm-3.5-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
dm raid1: set discard_zeroes_data_unsupported
dm thin: do not send discards to shared blocks
dm raid1: fix crash with mirror recovery and discard
We can't guarantee that REQ_DISCARD on dm-mirror zeroes the data even if
the underlying disks support zero on discard. So this patch sets
ti->discard_zeroes_data_unsupported.
For example, if the mirror is in the process of resynchronizing, it may
happen that kcopyd reads a piece of data, then discard is sent on the
same area and then kcopyd writes the piece of data to another leg.
Consequently, the data is not zeroed.
The flag was made available by commit 983c7db347db8ce2d8453fd1d89b7a4bb6920d56
(dm crypt: always disable discard_zeroes_data).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
When process_discard receives a partial discard that doesn't cover a
full block, it sends this discard down to that block. Unfortunately, the
block can be shared and the discard would corrupt the other snapshots
sharing this block.
This patch detects block sharing and ends the discard with success when
sending it to the shared block.
The above change means that if the device supports discard it can't be
guaranteed that a discard request zeroes data. Therefore, we set
ti->discard_zeroes_data_unsupported.
Thin target discard support with this bug arrived in commit
104655fd4dcebd50068ef30253a001da72e3a081 (dm thin: support discards).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch fixes a crash when a discard request is sent during mirror
recovery.
Firstly, some background. Generally, the following sequence happens during
mirror synchronization:
- function do_recovery is called
- do_recovery calls dm_rh_recovery_prepare
- dm_rh_recovery_prepare uses a semaphore to limit the number
simultaneously recovered regions (by default the semaphore value is 1,
so only one region at a time is recovered)
- dm_rh_recovery_prepare calls __rh_recovery_prepare,
__rh_recovery_prepare asks the log driver for the next region to
recover. Then, it sets the region state to DM_RH_RECOVERING. If there
are no pending I/Os on this region, the region is added to
quiesced_regions list. If there are pending I/Os, the region is not
added to any list. It is added to the quiesced_regions list later (by
dm_rh_dec function) when all I/Os finish.
- when the region is on quiesced_regions list, there are no I/Os in
flight on this region. The region is popped from the list in
dm_rh_recovery_start function. Then, a kcopyd job is started in the
recover function.
- when the kcopyd job finishes, recovery_complete is called. It calls
dm_rh_recovery_end. dm_rh_recovery_end adds the region to
recovered_regions or failed_recovered_regions list (depending on
whether the copy operation was successful or not).
The above mechanism assumes that if the region is in DM_RH_RECOVERING
state, no new I/Os are started on this region. When I/O is started,
dm_rh_inc_pending is called, which increases reg->pending count. When
I/O is finished, dm_rh_dec is called. It decreases reg->pending count.
If the count is zero and the region was in DM_RH_RECOVERING state,
dm_rh_dec adds it to the quiesced_regions list.
Consequently, if we call dm_rh_inc_pending/dm_rh_dec while the region is
in DM_RH_RECOVERING state, it could be added to quiesced_regions list
multiple times or it could be added to this list when kcopyd is copying
data (it is assumed that the region is not on any list while kcopyd does
its jobs). This results in memory corruption and crash.
There already exist bypasses for REQ_FLUSH requests: REQ_FLUSH requests
do not belong to any region, so they are always added to the sync list
in do_writes. dm_rh_inc_pending does not increase count for REQ_FLUSH
requests. In mirror_end_io, dm_rh_dec is never called for REQ_FLUSH
requests. These bypasses avoid the crash possibility described above.
These bypasses were improperly implemented for REQ_DISCARD when
the mirror target gained discard support in commit
5fc2ffeabb9ee0fc0e71ff16b49f34f0ed3d05b4 (dm raid1: support discard).
In do_writes, REQ_DISCARD requests is always added to the sync queue and
immediately dispatched (even if the region is in DM_RH_RECOVERING). However,
dm_rh_inc and dm_rh_dec is called for REQ_DISCARD resusts. So it violates the
rule that no I/Os are started on DM_RH_RECOVERING regions, and causes the list
corruption described above.
This patch changes it so that REQ_DISCARD requests follow the same path
as REQ_FLUSH. This avoids the crash.
Reference: https://bugzilla.redhat.com/837607
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add a per-stripe lock to protect stripe specific data. The purpose is to reduce
lock contention of conf->device_lock.
stripe ->toread, ->towrite are protected by per-stripe lock. Accessing bio
list of the stripe is always serialized by this lock, so adding bio to the
lists (add_stripe_bio()) and removing bio from the lists (like
ops_run_biofill()) not race.
If bio in ->read, ->written ... list are not shared by multiple stripes, we
don't need any lock to protect ->read, ->written, because STRIPE_ACTIVE will
protect them. If the bio are shared, there are two protections:
1. bi_phys_segments acts as a reference count
2. traverse the list uses r5_next_bio, which makes traverse never access bio
not belonging to the stripe
Let's have an example:
| stripe1 | stripe2 | stripe3 |
...bio1......|bio2|bio3|....bio4.....
stripe2 has 4 bios, when it's finished, it will decrement bi_phys_segments for
all bios, but only end_bio for bio2 and bio3. bio1->bi_next still points to
bio2, but this doesn't matter. When stripe1 is finished, it will not touch bio2
because of r5_next_bio check. Next time stripe1 will end_bio for bio1 and
stripe3 will end_bio bio4.
before add_stripe_bio() addes a bio to a stripe, we already increament the bio
bi_phys_segments, so don't worry other stripes release the bio.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Neil pointed out the bitmap write optimization in handle_stripe_clean_event()
is unnecessary, because the chance one stripe gets written twice in the mean
time is rare. We can always do a bitmap_startwrite when a write request is
added to a stripe and bitmap_endwrite after write request is done. Delete the
optimization. With it, we can delete some cases of device_lock.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Raid5 overrides bio->bi_phys_segments, accessing it is with device_lock hold,
which is unnecessary, We can make it lockless actually.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
release_stripe() is a place conf->device_lock is heavily contended. We take the
lock even stripe count isn't 1, which isn't required.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
commit 4367af556133723d0f443e14ca8170d9447317cb
md/raid1: clear bad-block record when write succeeds.
Added a 'reschedule_retry' call possibility at the end of
end_sync_write, but didn't add matching code at the end of
sync_request_write. So if the writes complete very quickly, or
scheduling makes it seem that way, then we can miss rescheduling
the request and the resync could hang.
Also commit 73d5c38a9536142e062c35997b044e89166e063b
md: avoid races when stopping resync.
Fix a race condition in this same code in end_sync_write but didn't
make the change in sync_request_write.
This patch updates sync_request_write to fix both of those.
Patch is suitable for 3.1 and later kernels.
Reported-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Original-version-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
md will refuse to stop an array if any other fd (or mounted fs) is
using it.
When any fs is unmounted of when the last open fd is closed all
pending IO will be flushed (e.g. sync_blockdev call in __blkdev_put)
so there will be no pending IO to worry about when the array is
stopped.
However in order to send the STOP_ARRAY ioctl to stop the array one
must first get and open fd on the block device.
If some fd is being used to write to the block device and it is closed
after mdadm open the block device, but before mdadm issues the
STOP_ARRAY ioctl, then there will be no last-close on the md device so
__blkdev_put will not call sync_blockdev.
If this happens, then IO can still be in-flight while md tears down
the array and bad things can happen (use-after-free and subsequent
havoc).
So in the case where do_md_stop is being called from an open file
descriptor, call sync_block after taking the mutex to ensure there
will be no new openers.
This is needed when setting a read-write device to read-only too.
Cc: stable@vger.kernel.org
Reported-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
commit c6563a8c38fde3c1c7fc925a10bde3ca20799301
md: add possibility to change data-offset for devices.
introduced a 'new_data_offset' attribute which should normally
be the same as 'data_offset', but can be explicitly set to a different
value to allow a reshape operation to move the data.
Unfortunately when the 'data_offset' is explicitly set through
sysfs, the new_data_offset is not also set, so the two would become
out-of-sync incorrectly.
One result of this is that trying to set the 'size' after the
'data_offset' would fail because it is not permitted to set the size
when the 'data_offset' and 'new_data_offset' are different - as that
can be confusing.
Consequently when mdadm tried to do this while assembling an IMSM
array it would fail.
This bug was introduced in 3.5-rc1.
Reported-by: Brian Downing <bdowning@lavos.net>
Bisected-by: Brian Downing <bdowning@lavos.net>
Tested-by: Brian Downing <bdowning@lavos.net>
Signed-off-by: NeilBrown <neilb@suse.de>
This bug has been present ever since data-check was introduce
in 2.6.16. However it would only fire if a data-check were
done on a degraded array, which was only possible if the array
has 3 or more devices. This is certainly possible, but is quite
uncommon.
Since hot-replace was added in 3.3 it can happen more often as
the same condition can arise if not all possible replacements are
present.
The problem is that as soon as we submit the last read request, the
'r1_bio' structure could be freed at any time, so we really should
stop looking at it. If the last device is being read from we will
stop looking at it. However if the last device is not due to be read
from, we will still check the bio pointer in the r1_bio, but the
r1_bio might already be free.
So use the read_targets counter to make sure we stop looking for bios
to submit as soon as we have submitted them all.
This fix is suitable for any -stable kernel since 2.6.16.
Cc: stable@vger.kernel.org
Reported-by: Arnold Schulz <arnysch@gmx.net>
Signed-off-by: NeilBrown <neilb@suse.de>
I really shouldn't do important things late in the day. It seems
that I get careless.
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Merge tag 'md-3.5-fixes' of git://neil.brown.name/md
Pull raid10 build failure fix from NeilBrown:
"I really shouldn't do important things late in the day. It seems that
I get careless."
* tag 'md-3.5-fixes' of git://neil.brown.name/md:
md/raid10: fix careless build error
build error introduced by commit b357f04a67c2aeee8
That function doesn't get extra args until a later patch. Bother.
Reported-by: Fengguang Wu <wfg@linux.intel.com>
Reported-by: Simon Kirby <sim@hostway.ca>
Reported-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Signed-off-by: NeilBrown <neilb@suse.de>
