linux/drivers/md, branch v3.0.87

dm snapshot: fix error return code in snapshot_ctr

2013-05-19T17:04:37Z

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

md: protect against crash upon fsync on ro array

2013-03-20T19:58:52Z

commit bbfa57c0f2243a7c31fd248d22e9861a2802cad5 upstream. If an fsync occurs on a read-only array, we need to send a completion for the IO and may not increment the active IO count. Otherwise, we hit a bug trace and can't stop the MD array anymore. By advice of Christoph Hellwig we return success upon a flush request but we return -EROFS for other writes. We detect flush requests by checking if the bio has zero sectors. Signed-off-by: Sebastian Riemer Cc: Christoph Hellwig Cc: Ben Hutchings Cc: NeilBrown Reported-by: Ben Hutchings Acked-by: Paul Menzel Signed-off-by: Greg Kroah-Hartman

md: raid0: fix error return from create_stripe_zones.

2013-03-14T18:32:05Z

commit 58ebb34c49fcfcaa029e4b1c1453d92583900f9a upstream. Create_stripe_zones returns an error slightly differently to raid0_run and to raid0_takeover_*. The error returned used by the second was wrong and an error would result in mddev->private being set to NULL and sooner or later a crash. So never return NULL, return ERR_PTR(err), not NULL from create_stripe_zones. This bug has been present since 2.6.35 so the fix is suitable for any kernel since then. Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

dm ioctl: prevent unsafe change to dm_ioctl data_size

2013-01-17T16:43:56Z

commit e910d7ebecd1aac43125944a8641b6cb1a0dfabe upstream. Abort dm ioctl processing if userspace changes the data_size parameter after we validated it but before we finished copying the data buffer from userspace. The dm ioctl parameters are processed in the following sequence: 1. ctl_ioctl() calls copy_params(); 2. copy_params() makes a first copy of the fixed-sized portion of the userspace parameters into the local variable "tmp"; 3. copy_params() then validates tmp.data_size and allocates a new structure big enough to hold the complete data and copies the whole userspace buffer there; 4. ctl_ioctl() reads userspace data the second time and copies the whole buffer into the pointer "param"; 5. ctl_ioctl() reads param->data_size without any validation and stores it in the variable "input_param_size"; 6. "input_param_size" is further used as the authoritative size of the kernel buffer. The problem is that userspace code could change the contents of user memory between steps 2 and 4. In particular, the data_size parameter can be changed to an invalid value after the kernel has validated it. This lets userspace force the kernel to access invalid kernel memory. The fix is to ensure that the size has not changed at step 4. This patch shouldn't have a security impact because CAP_SYS_ADMIN is required to run this code, but it should be fixed anyway. Reported-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm: fix deadlock with request based dm and queue request_fn recursion

2012-12-03T20:59:14Z

commit a8c32a5c98943d370ea606a2e7dc04717eb92206 upstream. Request based dm attempts to re-run the request queue off the request completion path. If used with a driver that potentially does end_io from its request_fn, we could deadlock trying to recurse back into request dispatch. Fix this by punting the request queue run to kblockd. Tested to fix a quickly reproducible deadlock in such a scenario. Acked-by: Alasdair G Kergon Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

dm: handle requests beyond end of device instead of using BUG_ON

2012-10-07T15:27:23Z

commit ba1cbad93dd47223b1f3b8edd50dd9ef2abcb2ed upstream. The access beyond the end of device BUG_ON that was introduced to dm_request_fn via commit 29e4013de7ad950280e4b2208 ("dm: implement REQ_FLUSH/FUA support for request-based dm") was an overly drastic (but simple) response to this situation. I have received a report that this BUG_ON was hit and now think it would be better to use dm_kill_unmapped_request() to fail the clone and original request with -EIO. map_request() will assign the valid target returned by dm_table_find_target to tio->ti. But when the target isn't valid tio->ti is never assigned (because map_request isn't called); so add a check for tio->ti != NULL to dm_done(). Reported-by: Mike Christie Signed-off-by: Mike Snitzer Signed-off-by: Jun'ichi Nomura Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

md: Don't truncate size at 4TB for RAID0 and Linear

2012-10-02T16:47:25Z

commit 667a5313ecd7308d79629c0738b0db588b0b0a4e upstream. commit 27a7b260f71439c40546b43588448faac01adb93 md: Fix handling for devices from 2TB to 4TB in 0.90 metadata. changed 0.90 metadata handling to truncated size to 4TB as that is all that 0.90 can record. However for RAID0 and Linear, 0.90 doesn't need to record the size, so this truncation is not needed and causes working arrays to become too small. So avoid the truncation for RAID0 and Linear This bug was introduced in 3.1 and is suitable for any stable kernels from then onwards. As the offending commit was tagged for 'stable', any stable kernel that it was applied to should also get this patch. That includes at least 2.6.32, 2.6.33 and 3.0. (Thanks to Ben Hutchings for providing that list). Signed-off-by: Neil Brown Signed-off-by: Greg Kroah-Hartman

dm raid1: fix crash with mirror recovery and discard

2012-08-01T19:26:54Z

commit 751f188dd5ab95b3f2b5f2f467c38aae5a2877eb upstream. This patch fixes a crash when a discard request is sent during mirror recovery. Firstly, some background. Generally, the following sequence happens during mirror synchronization: - function do_recovery is called - do_recovery calls dm_rh_recovery_prepare - dm_rh_recovery_prepare uses a semaphore to limit the number simultaneously recovered regions (by default the semaphore value is 1, so only one region at a time is recovered) - dm_rh_recovery_prepare calls __rh_recovery_prepare, __rh_recovery_prepare asks the log driver for the next region to recover. Then, it sets the region state to DM_RH_RECOVERING. If there are no pending I/Os on this region, the region is added to quiesced_regions list. If there are pending I/Os, the region is not added to any list. It is added to the quiesced_regions list later (by dm_rh_dec function) when all I/Os finish. - when the region is on quiesced_regions list, there are no I/Os in flight on this region. The region is popped from the list in dm_rh_recovery_start function. Then, a kcopyd job is started in the recover function. - when the kcopyd job finishes, recovery_complete is called. It calls dm_rh_recovery_end. dm_rh_recovery_end adds the region to recovered_regions or failed_recovered_regions list (depending on whether the copy operation was successful or not). The above mechanism assumes that if the region is in DM_RH_RECOVERING state, no new I/Os are started on this region. When I/O is started, dm_rh_inc_pending is called, which increases reg->pending count. When I/O is finished, dm_rh_dec is called. It decreases reg->pending count. If the count is zero and the region was in DM_RH_RECOVERING state, dm_rh_dec adds it to the quiesced_regions list. Consequently, if we call dm_rh_inc_pending/dm_rh_dec while the region is in DM_RH_RECOVERING state, it could be added to quiesced_regions list multiple times or it could be added to this list when kcopyd is copying data (it is assumed that the region is not on any list while kcopyd does its jobs). This results in memory corruption and crash. There already exist bypasses for REQ_FLUSH requests: REQ_FLUSH requests do not belong to any region, so they are always added to the sync list in do_writes. dm_rh_inc_pending does not increase count for REQ_FLUSH requests. In mirror_end_io, dm_rh_dec is never called for REQ_FLUSH requests. These bypasses avoid the crash possibility described above. These bypasses were improperly implemented for REQ_DISCARD when the mirror target gained discard support in commit 5fc2ffeabb9ee0fc0e71ff16b49f34f0ed3d05b4 (dm raid1: support discard). In do_writes, REQ_DISCARD requests is always added to the sync queue and immediately dispatched (even if the region is in DM_RH_RECOVERING). However, dm_rh_inc and dm_rh_dec is called for REQ_DISCARD resusts. So it violates the rule that no I/Os are started on DM_RH_RECOVERING regions, and causes the list corruption described above. This patch changes it so that REQ_DISCARD requests follow the same path as REQ_FLUSH. This avoids the crash. Reference: https://bugzilla.redhat.com/837607 Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

md/raid10: Don't try to recovery unmatched (and unused) chunks.

2012-07-16T15:47:52Z

commit fc448a18ae6219af9a73257b1fbcd009efab4a81 upstream. If a RAID10 has an odd number of chunks - as might happen when there are an odd number of devices - the last chunk has no pair and so is not mirrored. We don't store data there, but when recovering the last device in an array we retry to recover that last chunk from a non-existent location. This results in an error, and the recovery aborts. When we get to that last chunk we should just stop - there is nothing more to do anyway. This bug has been present since the introduction of RAID10, so the patch is appropriate for any -stable kernel. Reported-by: Christian Balzer Tested-by: Christian Balzer Signed-off-by: NeilBrown [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

md/raid5: Do not add data_offset before call to is_badblock

2012-07-16T15:47:51Z

commit 6c0544e255dd6582a9899572e120fb55d9f672a4 upstream. In chunk_aligned_read() we are adding data_offset before calling is_badblock. But is_badblock also adds data_offset, so that is bad. So move the addition of data_offset to after the call to is_badblock. This bug was introduced by commit 31c176ecdf3563140e639 md/raid5: avoid reading from known bad blocks. which first appeared in 3.0. So that patch is suitable for any -stable kernel from 3.0.y onwards. However it will need minor revision for most of those (as the comment didn't appear until recently). Signed-off-by: majianpeng Signed-off-by: NeilBrown [bwh: Backported to 3.2: ignored missing comment] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman