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260fa034ef
linux/drivers/md
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NeilBrown 260fa034ef md: avoid deadlock when dirty buffers during md_stop. 
When the last process closes /dev/mdX sync_blockdev will be called so
that all buffers get flushed.
So if it is then opened for the STOP_ARRAY ioctl to be sent there will
be nothing to flush.

However if we open /dev/mdX in order to send the STOP_ARRAY ioctl just
moments before some other process which was writing closes their file
descriptor, then there won't be a 'last close' and the buffers might
not get flushed.

So do_md_stop() calls sync_blockdev().  However at this point it is
holding ->reconfig_mutex.  So if the array is currently 'clean' then
the writes from sync_blockdev() will not complete until the array
can be marked dirty and that won't happen until some other thread
can get ->reconfig_mutex.  So we deadlock.

We need to move the sync_blockdev() call to before we take
->reconfig_mutex.
However then some other thread could open /dev/mdX and write to it
after we call sync_blockdev() and before we actually stop the array.
This can leave dirty data in the page cache which is awkward.

So introduce new flag MD_STILL_CLOSED.  Set it before calling
sync_blockdev(), clear it if anyone does open the file, and abort the
STOP_ARRAY attempt if it gets set before we lock against further
opens.

It is still possible to get problems if you open /dev/mdX, write to
it, then issue the STOP_ARRAY ioctl.  Just don't do that.

Signed-off-by: NeilBrown <neilb@suse.de>
2013-08-27 16:45:00 +10:00
..
bcache Merge branch 'for-3.11/drivers' of git://git.kernel.dk/linux-block 2013-07-22 19:02:52 -07:00
persistent-data dm persistent metadata: add space map threshold callback 2013-05-10 14:37:20 +01:00
bitmap.c md: replace strict_strto*() with kstrto*() 2013-06-14 08:10:26 +10:00
bitmap.h md/bitmap: record the space available for the bitmap in the superblock. 2012-05-22 13:55:34 +10:00
dm-bio-prison.c dm: add cache target 2013-03-01 22:45:51 +00:00
dm-bio-prison.h dm: add cache target 2013-03-01 22:45:51 +00:00
dm-bio-record.h
dm-bufio.c dm bufio: submit writes outside lock 2013-07-10 23:41:18 +01:00
dm-bufio.h dm bufio: prefetch 2012-03-28 18:41:29 +01:00
dm-cache-block-types.h dm: add cache target 2013-03-01 22:45:51 +00:00
dm-cache-metadata.c dm cache: replace memcpy with struct assignment 2013-05-10 14:37:18 +01:00
dm-cache-metadata.h dm cache: policy ignore hints if generated by different version 2013-03-20 17:21:28 +00:00
dm-cache-policy-cleaner.c dm cache: policy change version from string to integer set 2013-03-20 17:21:27 +00:00
dm-cache-policy-internal.h dm cache: policy change version from string to integer set 2013-03-20 17:21:27 +00:00
dm-cache-policy-mq.c dm cache: avoid conflicting remove_mapping() in mq policy 2013-08-16 15:56:51 -04:00
dm-cache-policy.c dm cache: policy change version from string to integer set 2013-03-20 17:21:27 +00:00
dm-cache-policy.h dm cache policy: fix description of lookup fn 2013-05-10 14:37:17 +01:00
dm-cache-target.c dm cache: fix arm link errors with inline 2013-07-10 23:41:17 +01:00
dm-crypt.c block: Convert some code to bio_for_each_segment_all() 2013-03-23 14:26:30 -07:00
dm-delay.c dm: rename request variables to bios 2013-03-01 22:45:47 +00:00
dm-exception-store.c dm: replace simple_strtoul 2012-07-27 15:07:59 +01:00
dm-exception-store.h
dm-flakey.c dm flakey: correct ctr alloc failure mesg 2013-07-10 23:41:17 +01:00
dm-io.c dm kcopyd: add WRITE SAME support to dm_kcopyd_zero 2012-12-21 20:23:37 +00:00
dm-ioctl.c dm: optimize use SRCU and RCU 2013-07-10 23:41:18 +01:00
dm-kcopyd.c dm kcopyd: introduce configurable throttling 2013-03-01 22:45:49 +00:00
dm-linear.c dm: rename request variables to bios 2013-03-01 22:45:47 +00:00
dm-log-userspace-base.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
dm-log-userspace-transfer.c connector/userns: replace netlink uses of cap_raised() with capable() 2012-05-10 23:21:39 -04:00
dm-log-userspace-transfer.h
dm-log.c dm: use memweight() 2012-07-30 17:25:16 -07:00
dm-mpath.c dm mpath: fix ioctl deadlock when no paths 2013-07-10 23:41:15 +01:00
dm-mpath.h
dm-path-selector.c md: Add module.h to all files using it implicitly 2011-10-31 19:31:18 -04:00
dm-path-selector.h
dm-queue-length.c dm: reject trailing characters in sccanf input 2012-03-28 18:41:26 +01:00
dm-raid1.c block: Use bio_sectors() more consistently 2013-03-23 14:15:30 -07:00
dm-raid.c MD: Remember the last sync operation that was performed 2013-06-26 12:38:24 +10:00
dm-region-hash.c dm raid1: fix crash with mirror recovery and discard 2012-07-20 14:25:03 +01:00
dm-round-robin.c dm: reject trailing characters in sccanf input 2012-03-28 18:41:26 +01:00
dm-service-time.c dm: reject trailing characters in sccanf input 2012-03-28 18:41:26 +01:00
dm-snap-persistent.c md: Add in export.h for files using EXPORT_SYMBOL 2011-10-31 19:31:19 -04:00
dm-snap-transient.c md: Add in export.h for files using EXPORT_SYMBOL 2011-10-31 19:31:19 -04:00
dm-snap.c dm snapshot: fix error return code in snapshot_ctr 2013-05-10 14:37:15 +01:00
dm-stripe.c dm stripe: fix regression in stripe_width calculation 2013-05-10 14:37:14 +01:00
dm-switch.c dm: add switch target 2013-07-10 23:41:19 +01:00
dm-sysfs.c
dm-table.c dm: optimize use SRCU and RCU 2013-07-10 23:41:18 +01:00
dm-target.c dm: rename request variables to bios 2013-03-01 22:45:47 +00:00
dm-thin-metadata.c dm thin: generate event when metadata threshold passed 2013-05-10 14:37:21 +01:00
dm-thin-metadata.h dm thin: generate event when metadata threshold passed 2013-05-10 14:37:21 +01:00
dm-thin.c dm thin: fix metadata dev resize detection 2013-05-19 18:57:50 +01:00
dm-uevent.c md: Add in export.h for files using EXPORT_SYMBOL 2011-10-31 19:31:19 -04:00
dm-uevent.h
dm-verity.c dm verity: use __ffs and __fls 2013-07-10 23:41:17 +01:00
dm-zero.c dm: rename request variables to bios 2013-03-01 22:45:47 +00:00
dm.c dm: optimize reorder structure 2013-07-10 23:41:18 +01:00
dm.h dm: introduce per_bio_data 2012-12-21 20:23:38 +00:00
faulty.c block: Add bio_end_sector() 2013-03-23 14:15:29 -07:00
Kconfig dm: add switch target 2013-07-10 23:41:19 +01:00
linear.c block: Add bio_end_sector() 2013-03-23 14:15:29 -07:00
linear.h md/linear: typedef removal: linear_conf_t -> struct linear_conf 2011-10-11 16:48:54 +11:00
Makefile dm: add switch target 2013-07-10 23:41:19 +01:00
md.c md: avoid deadlock when dirty buffers during md_stop. 2013-08-27 16:45:00 +10:00
md.h md: avoid deadlock when dirty buffers during md_stop. 2013-08-27 16:45:00 +10:00
multipath.c MD: change the parameter of md thread 2012-10-11 13:34:00 +11:00
multipath.h md/multipath: typedef removal: multipath_conf_t -> struct mpconf 2011-10-11 16:48:57 +11:00
raid0.c md: fix buglet in RAID5 -> RAID0 conversion. 2013-06-26 12:38:19 +10:00
raid0.h md: add proper merge_bvec handling to RAID0 and Linear. 2012-03-19 12:46:39 +11:00
raid1.c md/raid1: fix bio handling problems in process_checks() 2013-07-18 14:18:04 +10:00
raid1.h md/raid1: prevent merging too large request 2012-07-31 10:03:53 +10:00
raid5.c md/raid5: fix interaction of 'replace' and 'recovery'. 2013-07-25 16:46:57 +10:00
raid5.h md/raid5: fix interaction of 'replace' and 'recovery'. 2013-07-25 16:46:57 +10:00
raid10.c md/raid10: remove use-after-free bug. 2013-07-25 16:46:53 +10:00
raid10.h MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 1) 2013-02-26 11:55:30 +11:00