kernel/linux.git/drivers/md/dm-thin.c, branch v3.4.34

dm thin: fix memory leak in process_prepared_mapping error paths

2012-08-09T15:31:40+00:00

commit 905386f82d08f66726912f303f3e6605248c60a3 upstream. Fix memory leak in process_prepared_mapping by always freeing the dm_thin_new_mapping structs from the mapping_pool mempool on the error paths. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm thin: reduce endio_hook pool size

2012-08-09T15:31:40+00:00

commit 7768ed33ccdc02801c4483fc5682dc66ace14aea upstream. 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 Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm thin: do not send discards to shared blocks

2012-07-29T15:04:20+00:00

commit 650d2a06b4fe1cc1d218c20e256650f68bf0ca31 upstream. 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 Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm thin: fix table output when pool target disables discard passdown internally

2012-05-19T00:01:01+00:00

When the thin pool target clears the discard_passdown parameter internally, it incorrectly changes the table line reported to userspace. This breaks dumb string comparisons on these table lines in generic userspace device-mapper library code and leads to tables being reloaded repeatedly when nothing is actually meant to be changing. This patch corrects this by no longer changing the table line when discard passdown was disabled. We can still tell when discard passdown is overridden by looking for the message "Discard unsupported by data device (sdX): Disabling discard passdown." This automatic detection is also moved from the 'load' to the 'resume' so that it is re-evaluated should the properties of underlying devices change. Signed-off-by: Mike Snitzer Acked-by: Joe Thornber Signed-off-by: Alasdair G Kergon

dm thin: correct module description

2012-05-12T00:43:19+00:00

Remove duplicate copy of string "device-mapper" (DM_NAME) from MODULE_DESCRIPTION. Signed-off-by: Alasdair G Kergon

dm thin: fix unprotected use of prepared_discards list

2012-05-12T00:43:16+00:00

Fix two places in commit 104655fd4dce ("dm thin: support discards") that didn't use pool->lock to protect against concurrent changes to the prepared_discards list. Without this fix, thin_endio() can race with process_discard(), leading to concurrent list_add()s that result in the processes locking up with an error like the following: WARNING: at lib/list_debug.c:32 __list_add+0x8f/0xa0() ... list_add corruption. next->prev should be prev (ffff880323b96140), but was ffff8801d2c48440. (next=ffff8801d2c485c0). ... Pid: 17205, comm: kworker/u:1 Tainted: G W O 3.4.0-rc3.snitm+ #1 Call Trace: [] warn_slowpath_common+0x7f/0xc0 [] warn_slowpath_fmt+0x46/0x50 [] ? bio_detain+0xc6/0x210 [dm_thin_pool] [] __list_add+0x8f/0xa0 [] process_discard+0x2a2/0x2d0 [dm_thin_pool] [] ? remap_and_issue+0x38/0x50 [dm_thin_pool] [] process_deferred_bios+0x7b/0x230 [dm_thin_pool] [] ? process_deferred_bios+0x230/0x230 [dm_thin_pool] [] do_worker+0x52/0x60 [dm_thin_pool] [] process_one_work+0x129/0x450 [] worker_thread+0x17c/0x3c0 [] ? manage_workers+0x120/0x120 [] kthread+0x9e/0xb0 [] kernel_thread_helper+0x4/0x10 [] ? kthread_freezable_should_stop+0x70/0x70 [] ? gs_change+0x13/0x13 ---[ end trace 7e0a523bc5e52692 ]--- Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm thin: reinstate missing mempool_free in cell_release_singleton

2012-05-12T00:43:12+00:00

Fix a significant memory leak inadvertently introduced during simplification of cell_release_singleton() in commit 6f94a4c45a6f744383f9f695dde019998db3df55 ("dm thin: fix stacked bi_next usage"). A cell's hlist_del() must be accompanied by a mempool_free(). Use __cell_release() to do this, like before. Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm thin: add pool target flags to control discard

2012-03-28T17:41:29+00:00

Add dm thin target arguments to control discard support. ignore_discard: Disables discard support no_discard_passdown: Don't pass discards down to the underlying data device, but just remove the mapping within the thin provisioning target. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm thin: support discards

2012-03-28T17:41:28+00:00

Support discards in the thin target. On discard the corresponding mapping(s) are removed from the thin device. If the associated block(s) are no longer shared the discard is passed to the underlying device. All bios other than discards now have an associated deferred_entry that is saved to the 'all_io_entry' in endio_hook. When non-discard IO completes and associated mappings are quiesced any discards that were deferred, via ds_add_work() in process_discard(), will be queued for processing by the worker thread. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon drivers/md/dm-thin.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++---- drivers/md/dm-thin.c | 172 ++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 158 insertions(+), 14 deletions(-)

dm thin: prepare to support discard

2012-03-28T17:41:28+00:00

This patch contains the ground work needed for dm-thin to support discard. - Adds endio function that replaces shared_read_endio. - Introduce an explicit 'quiesced' flag into the new_mapping structure. Before, this was implicitly indicated by m->list being empty. - The map_info->ptr remains constant for the duration of a bio's trip through the thin target. Make it easier to reason about it. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon