linux/drivers/md
Mikulas Patocka aeb2deae26 dm crypt: fix mempool deadlock
This patch fixes a possible deadlock in dm-crypt's mempool use.

Currently, dm-crypt reserves a mempool of MIN_BIO_PAGES reserved pages.
It allocates first MIN_BIO_PAGES with non-failing allocation (the allocation
cannot fail and waits until the mempool is refilled). Further pages are
allocated with different gfp flags that allow failing.

Because allocations may be done in parallel, this code can deadlock. Example:
There are two processes, each tries to allocate MIN_BIO_PAGES and the processes
run simultaneously.
It may end up in a situation where each process allocates (MIN_BIO_PAGES / 2)
pages. The mempool is exhausted. Each process waits for more pages to be freed
to the mempool, which never happens.

To avoid this deadlock scenario, this patch changes the code so that only
the first page is allocated with non-failing gfp mask. Allocation of further
pages may fail.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-03-28 18:41:22 +01:00
..
persistent-data device-mapper: using EXPORT_SYBOL in dm-space-map-checker.c needs export.h 2011-11-07 10:29:10 -08:00
bitmap.c md updates for 3.4 2012-03-22 12:29:50 -07:00
bitmap.h md/bitmap: discard CHUNK_BLOCK_SHIFT macro 2012-03-19 12:46:41 +11:00
dm-bio-record.h
dm-bufio.c dm-bufio.c: there's no need to include linux/version.h 2012-02-03 22:38:12 +01:00
dm-bufio.h dm: add bufio 2011-10-31 20:19:09 +00:00
dm-crypt.c dm crypt: fix mempool deadlock 2012-03-28 18:41:22 +01:00
dm-delay.c dm: convert workqueues to alloc_ordered 2011-01-13 19:59:57 +00:00
dm-exception-store.c dm exception store: fix init error path 2012-03-28 18:41:22 +01:00
dm-exception-store.h
dm-flakey.c dm flakey: fix crash on read when corrupt_bio_byte not set 2012-03-07 19:09:39 +00:00
dm-io.c dm io: fix discard support 2012-03-07 19:09:37 +00:00
dm-ioctl.c dm ioctl: do not leak argv if target message only contains whitespace 2012-03-07 19:09:34 +00:00
dm-kcopyd.c dm kcopyd: add dm_kcopyd_zero to zero an area 2011-10-31 20:18:58 +00:00
dm-linear.c dm: do not forward ioctls from logical volumes to the underlying device 2012-01-14 15:07:24 -08:00
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 netlink: kill eff_cap from struct netlink_skb_parms 2011-03-03 13:32:07 -08:00
dm-log-userspace-transfer.h
dm-log.c dm: use vzalloc 2011-08-02 12:32:02 +01:00
dm-mpath.c dm: do not forward ioctls from logical volumes to the underlying device 2012-01-14 15:07:24 -08:00
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 atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
dm-raid1.c dm kcopyd: return client directly and not through a pointer 2011-05-29 13:03:13 +01:00
dm-raid.c md: tidy up rdev_for_each usage. 2012-03-19 12:46:39 +11:00
dm-region-hash.c Fix common misspellings 2011-03-31 11:26:23 -03:00
dm-round-robin.c md: Add module.h to all files using it implicitly 2011-10-31 19:31:18 -04:00
dm-service-time.c md: Add module.h to all files using it implicitly 2011-10-31 19:31:18 -04:00
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: skip reading origin when overwriting complete chunk 2011-08-02 12:32:04 +01:00
dm-stripe.c dm stripe: implement merge method 2011-03-24 13:54:35 +00:00
dm-sysfs.c
dm-table.c block: Introduce blk_set_stacking_limits function 2012-01-11 16:27:11 +01:00
dm-target.c
dm-thin-metadata.c dm thin metadata: decrement counter after removing mapped block 2012-03-07 19:09:44 +00:00
dm-thin-metadata.h dm: add thin provisioning target 2011-10-31 20:21:18 +00:00
dm-thin.c dm: add thin provisioning target 2011-10-31 20:21:18 +00:00
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-zero.c
dm.c fs: move code out of buffer.c 2012-01-03 22:54:07 -05:00
dm.h dm table: add immutable feature 2011-10-31 20:19:04 +00:00
faulty.c md: tidy up rdev_for_each usage. 2012-03-19 12:46:39 +11:00
Kconfig dm: add thin provisioning target 2011-10-31 20:21:18 +00:00
linear.c md: add proper merge_bvec handling to RAID0 and Linear. 2012-03-19 12:46:39 +11:00
linear.h md/linear: typedef removal: linear_conf_t -> struct linear_conf 2011-10-11 16:48:54 +11:00
Makefile dm: add thin provisioning target 2011-10-31 20:21:18 +00:00
md.c md: Add judgement bb->unacked_exist in function md_ack_all_badblocks(). 2012-03-19 12:46:42 +11:00
md.h md/raid10: handle merge_bvec_fn in member devices. 2012-03-19 12:46:39 +11:00
multipath.c md: tidy up rdev_for_each usage. 2012-03-19 12:46:39 +11:00
multipath.h md/multipath: typedef removal: multipath_conf_t -> struct mpconf 2011-10-11 16:48:57 +11:00
raid0.c md: add proper merge_bvec handling to RAID0 and Linear. 2012-03-19 12:46:39 +11:00
raid0.h md: add proper merge_bvec handling to RAID0 and Linear. 2012-03-19 12:46:39 +11:00
raid1.c md/raid1: handle merge_bvec_fn in member devices. 2012-03-19 12:46:39 +11:00
raid1.h md/raid1: Allocate spare to store replacement devices and their bios. 2011-12-23 10:17:56 +11:00
raid5.c md: tidy up rdev_for_each usage. 2012-03-19 12:46:39 +11:00
raid5.h md/raid5: detect and handle replacements during recovery. 2011-12-23 10:17:53 +11:00
raid10.c md/raid10 - support resizing some RAID10 arrays. 2012-03-19 12:46:40 +11:00
raid10.h md/raid10: prepare data structures for handling replacement. 2011-12-23 10:17:54 +11:00