linux/drivers/md, branch v3.9.6

dm cache: fix error return code in cache_create

2013-05-19T18:38:17Z

commit fa4d683af3693863bec761e2761a07e4c1351f86 upstream. Return -ENOMEM if memory allocation fails in cache_create instead of 0 (to avoid NULL pointer dereference). Signed-off-by: Wei Yongjun Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm snapshot: fix error return code in snapshot_ctr

2013-05-19T18:38:17Z

commit 09e8b813897a0f85bb401435d009228644c81214 upstream. Return -ENOMEM instead of success if unable to allocate pending exception mempool in snapshot_ctr. Signed-off-by: Wei Yongjun Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm bufio: avoid a possible __vmalloc deadlock

2013-05-19T18:38:16Z

commit 502624bdad3dba45dfaacaf36b7d83e39e74b2d2 upstream. This patch uses memalloc_noio_save to avoid a possible deadlock in dm-bufio. (it could happen only with large block size, at most PAGE_SIZE << MAX_ORDER (typically 8MiB). __vmalloc doesn't fully respect gfp flags. The specified gfp flags are used for allocation of requested pages, structures vmap_area, vmap_block and vm_struct and the radix tree nodes. However, the kernel pagetables are allocated always with GFP_KERNEL. Thus the allocation of pagetables can recurse back to the I/O layer and cause a deadlock. This patch uses the function memalloc_noio_save to set per-process PF_MEMALLOC_NOIO flag and the function memalloc_noio_restore to restore it. When this flag is set, all allocations in the process are done with implied GFP_NOIO flag, thus the deadlock can't happen. This should be backported to stable kernels, but they don't have the PF_MEMALLOC_NOIO flag and memalloc_noio_save/memalloc_noio_restore functions. So, PF_MEMALLOC should be set and restored instead. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm stripe: fix regression in stripe_width calculation

2013-05-19T18:38:16Z

commit d793e684277124d55c5d2444007e224635821346 upstream. Fix a regression in the calculation of the stripe_width in the dm stripe target which led to incorrect processing of device limits. The stripe_width is the stripe device length divided by the number of stripes. The group of commits in the range f14fa69 ("dm stripe: fix size test") to eb850de ("dm stripe: support for non power of 2 chunksize") interfered with each other (a merging error) and led to the stripe_width being set incorrectly to the stripe device length divided by chunk_size * stripe_count. For example, a stripe device's table with: 0 33553920 striped 3 512 ... should result in a stripe_width of 11184640 (33553920 / 3), but due to the bug it was getting set to 21845 (33553920 / (512 * 3)). The impact of this bug is that device topologies that previously worked fine with the stripe target are no longer considered valid. In particular, there is a higher risk of seeing this issue if one of the stripe devices has a 4K logical block size. Resulting in an error message like this: "device-mapper: table: 253:4: len=21845 not aligned to h/w logical block size 4096 of dm-1" The fix is to swap the order of the divisions and to use a temporary variable for the second one, so that width retains the intended value. Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm table: fix write same support

2013-05-19T18:38:15Z

commit dc019b21fb92d620a3b52ccecc135ac968a7c7ec upstream. If device_not_write_same_capable() returns true then the iterate_devices loop in dm_table_supports_write_same() should return false. Reported-by: Bharata B Rao Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

MD: ignore discard request for hard disks of hybid raid1/raid10 array

2013-05-08T03:33:13Z

commit 32f9f570d04461a41bdcd5c1d93b41ebc5ce182a upstream. In SSD/hard disk hybid storage, discard request should be ignored for hard disk. We used to be doing this way, but the unplug path forgets it. This is suitable for stable tree since v3.6. Reported-and-tested-by: Markus Signed-off-by: Shaohua Li Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

md: bad block list should default to disabled.

2013-05-08T03:33:12Z

commit 486adf72ccc0c235754923d47a2270c5dcb0c98b upstream. Maintenance of a bad-block-list currently defaults to 'enabled' and is then disabled when it cannot be supported. This is backwards and causes problem for dm-raid which didn't know to disable it. So fix the defaults, and only enabled for v1.x metadata which explicitly has bad blocks enabled. The problem with dm-raid has been present since badblock support was added in v3.1, so this patch is suitable for any -stable from 3.1 onwards. Reported-by: Jonathan Brassow Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

Revert "block: add missing block_bio_complete() tracepoint"

2013-04-18T16:00:26Z

This reverts commit 3a366e614d0837d9fc23f78cdb1a1186ebc3387f. Wanlong Gao reports that it causes a kernel panic on his machine several minutes after boot. Reverting it removes the panic. Jens says: "It's not quite clear why that is yet, so I think we should just revert the commit for 3.9 final (which I'm assuming is pretty close). The wifi is crap at the LSF hotel, so sending this email instead of queueing up a revert and pull request." Reported-by: Wanlong Gao Requested-by: Jens Axboe Cc: Tejun Heo Cc: Steven Rostedt Signed-off-by: Linus Torvalds

dm cache: reduce bio front_pad size in writeback mode

2013-04-05T14:36:34Z

A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm cache: fix writes to cache device in writethrough mode

2013-04-05T14:36:32Z

The dm-cache writethrough strategy introduced by commit e2e74d617eadc15 ("dm cache: fix race in writethrough implementation") issues a bio to the origin device, remaps and then issues the bio to the cache device. This more conservative in-series approach was selected to favor correctness over performance (of the previous parallel writethrough). However, this in-series implementation that reuses the same bio to write both the origin and cache device didn't take into account that the block layer's req_bio_endio() modifies a completing bio's bi_sector and bi_size. So the new writethrough strategy needs to preserve these bio fields, and restore them before submission to the cache device, otherwise nothing gets written to the cache (because bi_size is 0). This patch adds a struct dm_bio_details field to struct per_bio_data, and uses dm_bio_record() and dm_bio_restore() to ensure the bio is restored before reissuing to the cache device. Adding such a large structure to the per_bio_data is not ideal but we can improve this later, for now correctness is the important thing. This problem initially went unnoticed because the dm-cache test-suite uses a linear DM device for the dm-cache device's origin device. Writethrough worked as expected because DM submits a *clone* of the original bio, so the original bio which was reused for the cache was never touched. Signed-off-by: Darrick J. Wong Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon