linux-stable.git/drivers/md/persistent-data, branch v3.10.26

dm space map metadata: return on failure in sm_metadata_new_block

2013-12-20T15:45:11+00:00

commit f62b6b8f498658a9d537c7d380e9966f15e1b2a1 upstream.

Commit 2fc48021f4afdd109b9e52b6eef5db89ca80bac7 ("dm persistent
metadata: add space map threshold callback") introduced a regression
to the metadata block allocation path that resulted in errors being
ignored.  This regression was uncovered by running the following
device-mapper-test-suite test:
dmtest run --suite thin-provisioning -n /exhausting_metadata_space_causes_fail_mode/

The ignored error codes in sm_metadata_new_block() could crash the
kernel through use of either the dm-thin or dm-cache targets, e.g.:

device-mapper: thin: 253:4: reached low water mark for metadata device: sending event.
device-mapper: space map metadata: unable to allocate new metadata block
general protection fault: 0000 [#1] SMP
...
Workqueue: dm-thin do_worker [dm_thin_pool]
task: ffff880035ce2ab0 ti: ffff88021a054000 task.ti: ffff88021a054000
RIP: 0010:[]  [] metadata_ll_load_ie+0x15/0x30 [dm_persistent_data]
RSP: 0018:ffff88021a055a68  EFLAGS: 00010202
RAX: 003fc8243d212ba0 RBX: ffff88021a780070 RCX: ffff88021a055a78
RDX: ffff88021a055a78 RSI: 0040402222a92a80 RDI: ffff88021a780070
RBP: ffff88021a055a68 R08: ffff88021a055ba4 R09: 0000000000000010
R10: 0000000000000000 R11: 00000002a02e1000 R12: ffff88021a055ad4
R13: 0000000000000598 R14: ffffffffa0338470 R15: ffff88021a055ba4
FS:  0000000000000000(0000) GS:ffff88033fca0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f467c0291b8 CR3: 0000000001a0b000 CR4: 00000000000007e0
Stack:
 ffff88021a055ab8 ffffffffa0332020 ffff88021a055b30 0000000000000001
 ffff88021a055b30 0000000000000000 ffff88021a055b18 0000000000000000
 ffff88021a055ba4 ffff88021a055b98 ffff88021a055ae8 ffffffffa033304c
Call Trace:
 [] sm_ll_lookup_bitmap+0x40/0xa0 [dm_persistent_data]
 [] sm_metadata_count_is_more_than_one+0x8c/0xc0 [dm_persistent_data]
 [] dm_tm_shadow_block+0x65/0x110 [dm_persistent_data]
 [] sm_ll_mutate+0x80/0x300 [dm_persistent_data]
 [] ? set_ref_count+0x10/0x10 [dm_persistent_data]
 [] sm_ll_inc+0x1a/0x20 [dm_persistent_data]
 [] sm_disk_new_block+0x60/0x80 [dm_persistent_data]
 [] ? down_write+0x16/0x40
 [] dm_pool_alloc_data_block+0x54/0x80 [dm_thin_pool]
 [] alloc_data_block+0x9c/0x130 [dm_thin_pool]
 [] provision_block+0x4e/0x180 [dm_thin_pool]
 [] ? dm_thin_find_block+0x6a/0x110 [dm_thin_pool]
 [] process_bio+0x1ca/0x1f0 [dm_thin_pool]
 [] ? mempool_free+0x8d/0xa0
 [] process_deferred_bios+0xc5/0x230 [dm_thin_pool]
 [] do_worker+0x51/0x60 [dm_thin_pool]
 [] process_one_work+0x182/0x3b0
 [] worker_thread+0x120/0x3a0
 [] ? manage_workers+0x160/0x160
 [] kthread+0xce/0xe0
 [] ? kthread_freezable_should_stop+0x70/0x70
 [] ret_from_fork+0x7c/0xb0
 [] ? kthread_freezable_should_stop+0x70/0x70
 [] ret_from_fork+0x7c/0xb0
 [] ? kthread_freezable_should_stop+0x70/0x70

Signed-off-by: Mike Snitzer 
Acked-by: Joe Thornber 
Signed-off-by: Greg Kroah-Hartman

dm array: fix a reference counting bug in shadow_ablock

2013-12-20T15:45:11+00:00

commit ed9571f0cf1fe09d3506302610f3ccdfa1d22c4a upstream.

An old array block could have its reference count decremented below
zero when it is being replaced in the btree by a new array block.

The fix is to increment the old ablock's reference count just before
inserting a new ablock into the btree.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm array: fix bug in growing array

2013-12-04T18:56:42+00:00

commit 9c1d4de56066e4d6abc66ec188faafd7b303fb08 upstream.

Entries would be lost if the old tail block was partially filled.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm persistent metadata: add space map threshold callback

2013-05-10T13:37:20+00:00

Add a threshold callback to dm persistent data space maps.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm persistent data: add threshold callback to space map

2013-05-10T13:37:20+00:00

Add a threshold callback function to the persistent data space map
interface for a subsequent patch to use.

dm-thin and dm-cache are interested in knowing when they're getting
low on metadata or data blocks.  This patch introduces a new method
for registering a callback against a threshold.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm persistent data: support space map resizing

2013-05-10T13:37:19+00:00

Support extending a dm persistent data metadata space map.

The extend itself is implemented by switching back to the boostrap
allocator and pointing to the new space.  The extra bitmap indexes are
then allocated from the new space, and finally we switch back to the
proper space map ops and tweak the reference counts.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm persistent data: fix error message typos

2013-05-10T13:37:17+00:00

Fix some typos in dm-space-map-metadata.c error messages.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm thin: fix discard corruption

2013-03-20T17:21:24+00:00

Fix a bug in dm_btree_remove that could leave leaf values with incorrect
reference counts.  The effect of this was that removal of a shared block
could result in the space maps thinking the block was no longer used.
More concretely, if you have a thin device and a snapshot of it, sending
a discard to a shared region of the thin could corrupt the snapshot.

Thinp uses a 2-level nested btree to store it's mappings.  This first
level is indexed by thin device, and the second level by logical
block.

Often when we're removing an entry in this mapping tree we need to
rebalance nodes, which can involve shadowing them, possibly creating a
copy if the block is shared.  If we do create a copy then children of
that node need to have their reference counts incremented.  In this
way reference counts percolate down the tree as shared trees diverge.

The rebalance functions were incrementing the children at the
appropriate time, but they were always assuming the children were
internal nodes.  This meant the leaf values (in our case packed
block/flags entries) were not being incremented.

Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm: add cache target

2013-03-01T22:45:51+00:00

Add a target that allows a fast device such as an SSD to be used as a
cache for a slower device such as a disk.

A plug-in architecture was chosen so that the decisions about which data
to migrate and when are delegated to interchangeable tunable policy
modules.  The first general purpose module we have developed, called
"mq" (multiqueue), follows in the next patch.  Other modules are
under development.

Signed-off-by: Joe Thornber 
Signed-off-by: Heinz Mauelshagen 
Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm persistent data: add bitset

2013-03-01T22:45:51+00:00

Add a persistent bitset as a wrapper around dm-array.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon