user/sven/linux.git/drivers/md, branch v3.12.25

dm io: fix a race condition in the wake up code for sync_io

2014-07-18T13:51:24Z

commit 10f1d5d111e8aed46a0f1179faf9a3cf422f689e upstream. There's a race condition between the atomic_dec_and_test(&io->count) in dec_count() and the waking of the sync_io() thread. If the thread is spuriously woken immediately after the decrement it may exit, making the on stack io struct invalid, yet the dec_count could still be using it. Fix this race by using a completion in sync_io() and dec_count(). Reported-by: Minfei Huang Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Acked-by: Mikulas Patocka Signed-off-by: Jiri Slaby

md: flush writes before starting a recovery.

2014-07-18T13:51:08Z

commit 133d4527eab8d199a62eee6bd433f0776842df2e upstream. When we write to a degraded array which has a bitmap, we make sure the relevant bit in the bitmap remains set when the write completes (so a 're-add' can quickly rebuilt a temporarily-missing device). If, immediately after such a write starts, we incorporate a spare, commence recovery, and skip over the region where the write is happening (because the 'needs recovery' flag isn't set yet), then that write will not get to the new device. Once the recovery finishes the new device will be trusted, but will have incorrect data, leading to possible corruption. We cannot set the 'needs recovery' flag when we start the write as we do not know easily if the write will be "degraded" or not. That depends on details of the particular raid level and particular write request. This patch fixes a corruption issue of long standing and so it suitable for any -stable kernel. It applied correctly to 3.0 at least and will minor editing to earlier kernels. Reported-by: Bill Tested-by: Bill Link: http://lkml.kernel.org/r/53A518BB.60709@sbcglobal.net Signed-off-by: NeilBrown Signed-off-by: Jiri Slaby

dm thin: update discard_granularity to reflect the thin-pool blocksize

2014-07-17T13:04:38Z

commit 09869de57ed2728ae3c619803932a86cb0e2c4f8 upstream. DM thinp already checks whether the discard_granularity of the data device is a factor of the thin-pool block size. But when using the dm-thin-pool's discard passdown support, DM thinp was not selecting the max of the underlying data device's discard_granularity and the thin-pool's block size. Update set_discard_limits() to set discard_granularity to the max of these values. This enables blkdev_issue_discard() to properly align the discards that are sent to the DM thin device on a full block boundary. As such each discard will now cover an entire DM thin-pool block and the block will be reclaimed. Reported-by: Zdenek Kabelac Signed-off-by: Lukas Czerner Signed-off-by: Mike Snitzer Signed-off-by: Jiri Slaby

md: always set MD_RECOVERY_INTR when interrupting a reshape thread.

2014-06-20T15:34:03Z

commit 2ac295a544dcae9299cba13ce250419117ae7fd1 upstream. Commit 8313b8e57f55b15e5b7f7fc5d1630bbf686a9a97 md: fix problem when adding device to read-only array with bitmap. added a called to md_reap_sync_thread() which cause a reshape thread to be interrupted (in particular, it could cause md_thread() to never even call md_do_sync()). However it didn't set MD_RECOVERY_INTR so ->finish_reshape() would not know that the reshape didn't complete. This only happens when mddev->ro is set and normally reshape threads don't run in that situation. But raid5 and raid10 can start a reshape thread during "run" is the array is in the middle of a reshape. They do this even if ->ro is set. So it is best to set MD_RECOVERY_INTR before abortingg the sync thread, just in case. Though it rare for this to trigger a problem it can cause data corruption because the reshape isn't finished properly. So it is suitable for any stable which the offending commit was applied to. (3.2 or later) Fixes: 8313b8e57f55b15e5b7f7fc5d1630bbf686a9a97 Signed-off-by: NeilBrown Signed-off-by: Jiri Slaby

md: always set MD_RECOVERY_INTR when aborting a reshape or other "resync".

2014-06-20T15:34:03Z

commit 3991b31ea072b070081ca3bfa860a077eda67de5 upstream. If mddev->ro is set, md_to_sync will (correctly) abort. However in that case MD_RECOVERY_INTR isn't set. If a RESHAPE had been requested, then ->finish_reshape() will be called and it will think the reshape was successful even though nothing happened. Normally a resync will not be requested if ->ro is set, but if an array is stopped while a reshape is on-going, then when the array is started, the reshape will be restarted. If the array is also set read-only at this point, the reshape will instantly appear to success, resulting in data corruption. Consequently, this patch is suitable for any -stable kernel. Signed-off-by: NeilBrown Signed-off-by: Jiri Slaby

dm cache: always split discards on cache block boundaries

2014-06-20T15:34:00Z

commit f1daa838e861ae1a0fb7cd9721a21258430fcc8c upstream. The DM cache target cannot cope with discards that span multiple cache blocks, so each discard bio that spans more than one cache block must get split by the DM core. Signed-off-by: Heinz Mauelshagen Acked-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Jiri Slaby

dm crypt: fix cpu hotplug crash by removing per-cpu structure

2014-06-09T13:53:49Z

commit 610f2de3559c383caf8fbbf91e9968102dff7ca0 upstream. The DM crypt target used per-cpu structures to hold pointers to a ablkcipher_request structure. The code assumed that the work item keeps executing on a single CPU, so it didn't use synchronization when accessing this structure. If a CPU is disabled by writing 0 to /sys/devices/system/cpu/cpu*/online, the work item could be moved to another CPU. This causes dm-crypt crashes, like the following, because the code starts using an incorrect ablkcipher_request: smpboot: CPU 7 is now offline BUG: unable to handle kernel NULL pointer dereference at 0000000000000130 IP: [] crypt_convert+0x12d/0x3c0 [dm_crypt] ... Call Trace: [] ? kcryptd_crypt+0x305/0x470 [dm_crypt] [] ? finish_task_switch+0x40/0xc0 [] ? process_one_work+0x168/0x470 [] ? worker_thread+0x10b/0x390 [] ? manage_workers.isra.26+0x290/0x290 [] ? kthread+0xaf/0xc0 [] ? kthread_create_on_node+0x120/0x120 [] ? ret_from_fork+0x7c/0xb0 [] ? kthread_create_on_node+0x120/0x120 Fix this bug by removing the per-cpu definition. The structure ablkcipher_request is accessed via a pointer from convert_context. Consequently, if the work item is rescheduled to a different CPU, the thread still uses the same ablkcipher_request. This change may undermine performance improvements intended by commit c0297721 ("dm crypt: scale to multiple cpus") on select hardware. In practice no performance difference was observed on recent hardware. But regardless, correctness is more important than performance. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Jiri Slaby

md: avoid possible spinning md thread at shutdown.

2014-06-06T09:40:25Z

commit 0f62fb220aa4ebabe8547d3a9ce4a16d3c045f21 upstream. If an md array with externally managed metadata (e.g. DDF or IMSM) is in use, then we should not set safemode==2 at shutdown because: 1/ this is ineffective: user-space need to be involved in any 'safemode' handling, 2/ The safemode management code doesn't cope with safemode==2 on external metadata and md_check_recover enters an infinite loop. Even at shutdown, an infinite-looping process can be problematic, so this could cause shutdown to hang. Signed-off-by: NeilBrown Signed-off-by: Jiri Slaby

md/raid1: r1buf_pool_alloc: free allocate pages when subsequent allocation fails.

2014-05-29T09:38:14Z

commit da1aab3dca9aa88ae34ca392470b8943159e25fe upstream. When performing a user-request check/repair (MD_RECOVERY_REQUEST is set) on a raid1, we allocate multiple bios each with their own set of pages. If the page allocations for one bio fails, we currently do *not* free the pages allocated for the previous bios, nor do we free the bio itself. This patch frees all the already-allocate pages, and makes sure that all the bios are freed as well. This bug can cause a memory leak which can ultimately OOM a machine. It was introduced in 3.10-rc1. Fixes: a07876064a0b73ab5ef1ebcf14b1cf0231c07858 Cc: Kent Overstreet Reported-by: Russell King - ARM Linux Signed-off-by: NeilBrown Signed-off-by: Jiri Slaby

dm thin: fix dangling bio in process_deferred_bios error path

2014-05-15T07:56:14Z

commit fe76cd88e654124d1431bb662a0fc6e99ca811a5 upstream. If unable to ensure_next_mapping() we must add the current bio, which was removed from the @bios list via bio_list_pop, back to the deferred_bios list before all the remaining @bios. Signed-off-by: Mike Snitzer Acked-by: Joe Thornber Signed-off-by: Jiri Slaby