1. 20 Jul, 2016 1 commit
    • Toshi Kani's avatar
      dm: add infrastructure for DAX support · 545ed20e
      Toshi Kani authored
      Change mapped device to implement direct_access function,
      dm_blk_direct_access(), which calls a target direct_access function.
      'struct target_type' is extended to have target direct_access interface.
      This function limits direct accessible size to the dm_target's limit
      with max_io_len().
      Add dm_table_supports_dax() to iterate all targets and associated block
      devices to check for DAX support.  To add DAX support to a DM target the
      target must only implement the direct_access function.
      Add a new dm type, DM_TYPE_DAX_BIO_BASED, which indicates that mapped
      device supports DAX and is bio based.  This new type is used to assure
      that all target devices have DAX support and remain that way after
      QUEUE_FLAG_DAX is set in mapped device.
      At initial table load, QUEUE_FLAG_DAX is set to mapped device when setting
      DM_TYPE_DAX_BIO_BASED to the type.  Any subsequent table load to the
      mapped device must have the same type, or else it fails per the check in
      Signed-off-by: default avatarToshi Kani <toshi.kani@hpe.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
  2. 10 Jun, 2016 1 commit
    • Mike Snitzer's avatar
      dm mpath: add optional "queue_mode" feature · e83068a5
      Mike Snitzer authored
      Allow a user to specify an optional feature 'queue_mode <mode>' where
      <mode> may be "bio", "rq" or "mq" -- which corresponds to bio-based,
      request_fn rq-based, and blk-mq rq-based respectively.
      If the queue_mode feature isn't specified the default for the
      "multipath" target is still "rq" but if dm_mod.use_blk_mq is set to Y
      it'll default to mode "mq".
      This new queue_mode feature introduces the ability for each multipath
      device to have its own queue_mode (whereas before this feature all
      multipath devices effectively had to have the same queue_mode).
      This commit also goes a long way to eliminate the awkward (ab)use of
      DM_TYPE_*, the associated filter_md_type() and other relatively fragile
      and difficult to maintain code.
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
  3. 10 Mar, 2016 1 commit
    • DingXiang's avatar
      dm snapshot: disallow the COW and origin devices from being identical · 4df2bf46
      DingXiang authored
      Otherwise loading a "snapshot" table using the same device for the
      origin and COW devices, e.g.:
      echo "0 20971520 snapshot 253:3 253:3 P 8" | dmsetup create snap
      will trigger:
      BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
      [ 1958.979934] IP: [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot]
      [ 1958.989655] PGD 0
      [ 1958.991903] Oops: 0000 [#1] SMP
      [ 1959.059647] CPU: 9 PID: 3556 Comm: dmsetup Tainted: G          IO    4.5.0-rc5.snitm+ #150
      [ 1959.083517] task: ffff8800b9660c80 ti: ffff88032a954000 task.ti: ffff88032a954000
      [ 1959.091865] RIP: 0010:[<ffffffffa040efba>]  [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot]
      [ 1959.104295] RSP: 0018:ffff88032a957b30  EFLAGS: 00010246
      [ 1959.110219] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000001
      [ 1959.118180] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff880329334a00
      [ 1959.126141] RBP: ffff88032a957b50 R08: 0000000000000000 R09: 0000000000000001
      [ 1959.134102] R10: 000000000000000a R11: f000000000000000 R12: ffff880330884d80
      [ 1959.142061] R13: 0000000000000008 R14: ffffc90001c13088 R15: ffff880330884d80
      [ 1959.150021] FS:  00007f8926ba3840(0000) GS:ffff880333440000(0000) knlGS:0000000000000000
      [ 1959.159047] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [ 1959.165456] CR2: 0000000000000098 CR3: 000000032f48b000 CR4: 00000000000006e0
      [ 1959.173415] Stack:
      [ 1959.175656]  ffffc90001c13040 ffff880329334a00 ffff880330884ed0 ffff88032a957bdc
      [ 1959.183946]  ffff88032a957bb8 ffffffffa040f225 ffff880329334a30 ffff880300000000
      [ 1959.192233]  ffffffffa04133e0 ffff880329334b30 0000000830884d58 00000000569c58cf
      [ 1959.200521] Call Trace:
      [ 1959.203248]  [<ffffffffa040f225>] dm_exception_store_create+0x1d5/0x240 [dm_snapshot]
      [ 1959.211986]  [<ffffffffa040d310>] snapshot_ctr+0x140/0x630 [dm_snapshot]
      [ 1959.219469]  [<ffffffffa0005c44>] ? dm_split_args+0x64/0x150 [dm_mod]
      [ 1959.226656]  [<ffffffffa0005ea7>] dm_table_add_target+0x177/0x440 [dm_mod]
      [ 1959.234328]  [<ffffffffa0009203>] table_load+0x143/0x370 [dm_mod]
      [ 1959.241129]  [<ffffffffa00090c0>] ? retrieve_status+0x1b0/0x1b0 [dm_mod]
      [ 1959.248607]  [<ffffffffa0009e35>] ctl_ioctl+0x255/0x4d0 [dm_mod]
      [ 1959.255307]  [<ffffffff813304e2>] ? memzero_explicit+0x12/0x20
      [ 1959.261816]  [<ffffffffa000a0c3>] dm_ctl_ioctl+0x13/0x20 [dm_mod]
      [ 1959.268615]  [<ffffffff81215eb6>] do_vfs_ioctl+0xa6/0x5c0
      [ 1959.274637]  [<ffffffff81120d2f>] ? __audit_syscall_entry+0xaf/0x100
      [ 1959.281726]  [<ffffffff81003176>] ? do_audit_syscall_entry+0x66/0x70
      [ 1959.288814]  [<ffffffff81216449>] SyS_ioctl+0x79/0x90
      [ 1959.294450]  [<ffffffff8167e4ae>] entry_SYSCALL_64_fastpath+0x12/0x71
      [ 1959.323277] RIP  [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot]
      [ 1959.333090]  RSP <ffff88032a957b30>
      [ 1959.336978] CR2: 0000000000000098
      [ 1959.344121] ---[ end trace b049991ccad1169e ]---
      Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1195899
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarDing Xiang <dingxiang@huawei.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
  4. 22 Feb, 2016 2 commits
  5. 31 Oct, 2015 1 commit
    • Christoph Hellwig's avatar
      dm: refactor ioctl handling · e56f81e0
      Christoph Hellwig authored
      This moves the call to blkdev_ioctl and the argument checking to DM core
      code, and only leaves a callout to find the block device to operate on
      in the targets.  This simplifies the code and allows us to pass through
      ioctl-like command using other methods in the next patch.
      Also split out a helper around calling the prepare_ioctl method that
      will be reused for persistent reservation handling.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
  6. 13 Aug, 2015 1 commit
    • Kent Overstreet's avatar
      block: kill merge_bvec_fn() completely · 8ae12666
      Kent Overstreet authored
      As generic_make_request() is now able to handle arbitrarily sized bios,
      it's no longer necessary for each individual block driver to define its
      own ->merge_bvec_fn() callback. Remove every invocation completely.
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
      Cc: drbd-user@lists.linbit.com
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Yehuda Sadeh <yehuda@inktank.com>
      Cc: Sage Weil <sage@inktank.com>
      Cc: Alex Elder <elder@kernel.org>
      Cc: ceph-devel@vger.kernel.org
      Cc: Alasdair Kergon <agk@redhat.com>
      Cc: Mike Snitzer <snitzer@redhat.com>
      Cc: dm-devel@redhat.com
      Cc: Neil Brown <neilb@suse.de>
      Cc: linux-raid@vger.kernel.org
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
      Acked-by: NeilBrown <neilb@suse.de> (for the 'md' bits)
      Acked-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
      [dpark: also remove ->merge_bvec_fn() in dm-thin as well as
       dm-era-target, and resolve merge conflicts]
      Signed-off-by: default avatarDongsu Park <dpark@posteo.net>
      Signed-off-by: default avatarMing Lin <ming.l@ssi.samsung.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
  7. 31 Mar, 2015 1 commit
  8. 27 Feb, 2015 1 commit
    • Mikulas Patocka's avatar
      dm snapshot: suspend merging snapshot when doing exception handover · 09ee96b2
      Mikulas Patocka authored
      The "dm snapshot: suspend origin when doing exception handover" commit
      fixed a exception store handover bug associated with pending exceptions
      to the "snapshot-origin" target.
      However, a similar problem exists in snapshot merging.  When snapshot
      merging is in progress, we use the target "snapshot-merge" instead of
      "snapshot-origin".  Consequently, during exception store handover, we
      must find the snapshot-merge target and suspend its associated
      To avoid lockdep warnings, the target must be suspended and resumed
      without holding _origins_lock.
      Introduce a dm_hold() function that grabs a reference on a
      mapped_device, but unlike dm_get(), it doesn't crash if the device has
      the DMF_FREEING flag set, it returns an error in this case.
      In snapshot_resume() we grab the reference to the origin device using
      dm_hold() while holding _origins_lock (_origins_lock guarantees that the
      device won't disappear).  Then we release _origins_lock, suspend the
      device and grab _origins_lock again.
      NOTE to stable@ people:
      When backporting to kernels 3.18 and older, use dm_internal_suspend and
      dm_internal_resume instead of dm_internal_suspend_fast and
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Cc: stable@vger.kernel.org
  9. 09 Feb, 2015 2 commits
    • Mike Snitzer's avatar
      dm: allocate requests in target when stacking on blk-mq devices · e5863d9a
      Mike Snitzer authored
      For blk-mq request-based DM the responsibility of allocating a cloned
      request is transfered from DM core to the target type.  Doing so
      enables the cloned request to be allocated from the appropriate
      blk-mq request_queue's pool (only the DM target, e.g. multipath, can
      know which block device to send a given cloned request to).
      Care was taken to preserve compatibility with old-style block request
      completion that requires request-based DM _not_ acquire the clone
      request's queue lock in the completion path.  As such, there are now 2
      different request-based DM target_type interfaces:
      1) the original .map_rq() interface will continue to be used for
         non-blk-mq devices -- the preallocated clone request is passed in
         from DM core.
      2) a new .clone_and_map_rq() and .release_clone_rq() will be used for
         blk-mq devices -- blk_get_request() and blk_put_request() are used
         respectively from these hooks.
      dm_table_set_type() was updated to detect if the request-based target is
      being stacked on blk-mq devices, if so DM_TYPE_MQ_REQUEST_BASED is set.
      DM core disallows switching the DM table's type after it is set.  This
      means that there is no mixing of non-blk-mq and blk-mq devices within
      the same request-based DM table.
      [This patch was started by Keith and later heavily modified by Mike]
      Tested-by: default avatarBart Van Assche <bvanassche@acm.org>
      Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
    • Mike Snitzer's avatar
      dm: remove exports for request-based interfaces without external callers · dbf9782c
      Mike Snitzer authored
      Remove exports for dm_dispatch_request, dm_requeue_unmapped_request,
      and dm_kill_unmapped_request.
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
  10. 19 Nov, 2014 1 commit
  11. 04 Jun, 2014 1 commit
  12. 03 Jun, 2014 1 commit
  13. 27 Mar, 2014 2 commits
  14. 20 Sep, 2013 1 commit
    • Mike Snitzer's avatar
      dm mpath: disable WRITE SAME if it fails · f84cb8a4
      Mike Snitzer authored
      Workaround the SCSI layer's problematic WRITE SAME heuristics by
      disabling WRITE SAME in the DM multipath device's queue_limits if an
      underlying device disabled it.
      The WRITE SAME heuristics, with both the original commit 5db44863
      ("[SCSI] sd: Implement support for WRITE SAME") and the updated commit
      66c28f97 ("[SCSI] sd: Update WRITE SAME heuristics"), default to enabling
      WRITE SAME(10) even without successfully determining it is supported.
      After the first failed WRITE SAME the SCSI layer will disable WRITE SAME
      for the device (by setting sdkp->device->no_write_same which results in
      'max_write_same_sectors' in device's queue_limits to be set to 0).
      When a device is stacked ontop of such a SCSI device any changes to that
      SCSI device's queue_limits do not automatically propagate up the stack.
      As such, a DM multipath device will not have its WRITE SAME support
      disabled.  This causes the block layer to continue to issue WRITE SAME
      requests to the mpath device which causes paths to fail and (if mpath IO
      isn't configured to queue when no paths are available) it will result in
      actual IO errors to the upper layers.
      This fix doesn't help configurations that have additional devices
      stacked ontop of the mpath device (e.g. LVM created linear DM devices
      ontop).  A proper fix that restacks all the queue_limits from the bottom
      of the device stack up will need to be explored if SCSI will continue to
      use this model of optimistically allowing op codes and then disabling
      them after they fail for the first time.
      Before this patch:
      EXT4-fs (dm-6): mounted filesystem with ordered data mode. Opts: (null)
      device-mapper: multipath: XXX snitm debugging: got -EREMOTEIO (-121)
      device-mapper: multipath: XXX snitm debugging: failing WRITE SAME IO with error=-121
      end_request: critical target error, dev dm-6, sector 528
      dm-6: WRITE SAME failed. Manually zeroing.
      device-mapper: multipath: Failing path 8:112.
      end_request: I/O error, dev dm-6, sector 4616
      dm-6: WRITE SAME failed. Manually zeroing.
      end_request: I/O error, dev dm-6, sector 4616
      end_request: I/O error, dev dm-6, sector 5640
      end_request: I/O error, dev dm-6, sector 6664
      end_request: I/O error, dev dm-6, sector 7688
      end_request: I/O error, dev dm-6, sector 524288
      Buffer I/O error on device dm-6, logical block 65536
      lost page write due to I/O error on dm-6
      JBD2: Error -5 detected when updating journal superblock for dm-6-8.
      end_request: I/O error, dev dm-6, sector 524296
      Aborting journal on device dm-6-8.
      end_request: I/O error, dev dm-6, sector 524288
      Buffer I/O error on device dm-6, logical block 65536
      lost page write due to I/O error on dm-6
      JBD2: Error -5 detected when updating journal superblock for dm-6-8.
      # cat /sys/block/sdh/queue/write_same_max_bytes
      # cat /sys/block/dm-6/queue/write_same_max_bytes
      After this patch:
      EXT4-fs (dm-6): mounted filesystem with ordered data mode. Opts: (null)
      device-mapper: multipath: XXX snitm debugging: got -EREMOTEIO (-121)
      device-mapper: multipath: XXX snitm debugging: WRITE SAME I/O failed with error=-121
      end_request: critical target error, dev dm-6, sector 528
      dm-6: WRITE SAME failed. Manually zeroing.
      # cat /sys/block/sdh/queue/write_same_max_bytes
      # cat /sys/block/dm-6/queue/write_same_max_bytes
      It should be noted that WRITE SAME support wasn't enabled in DM
      multipath until v3.10.
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Cc: Martin K. Petersen <martin.petersen@oracle.com>
      Cc: Hannes Reinecke <hare@suse.de>
      Cc: stable@vger.kernel.org # 3.10+
  15. 05 Sep, 2013 1 commit
    • Mikulas Patocka's avatar
      dm: add statistics support · fd2ed4d2
      Mikulas Patocka authored
      Support the collection of I/O statistics on user-defined regions of
      a DM device.  If no regions are defined no statistics are collected so
      there isn't any performance impact.  Only bio-based DM devices are
      currently supported.
      Each user-defined region specifies a starting sector, length and step.
      Individual statistics will be collected for each step-sized area within
      the range specified.
      The I/O statistics counters for each step-sized area of a region are
      in the same format as /sys/block/*/stat or /proc/diskstats but extra
      counters (12 and 13) are provided: total time spent reading and
      writing in milliseconds.  All these counters may be accessed by sending
      the @stats_print message to the appropriate DM device via dmsetup.
      The creation of DM statistics will allocate memory via kmalloc or
      fallback to using vmalloc space.  At most, 1/4 of the overall system
      memory may be allocated by DM statistics.  The admin can see how much
      memory is used by reading
      See Documentation/device-mapper/statistics.txt for more details.
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
  16. 10 Jul, 2013 1 commit
    • Mikulas Patocka's avatar
      dm: optimize use SRCU and RCU · 83d5e5b0
      Mikulas Patocka authored
      This patch removes "io_lock" and "map_lock" in struct mapped_device and
      "holders" in struct dm_table and replaces these mechanisms with
      Previously, the code would call "dm_get_live_table" and "dm_table_put" to
      get and release table. Now, the code is changed to call "dm_get_live_table"
      and "dm_put_live_table". dm_get_live_table locks sleepable-rcu and
      dm_put_live_table unlocks it.
      dm_get_live_table_fast/dm_put_live_table_fast can be used instead of
      dm_get_live_table/dm_put_live_table. These *_fast functions use
      non-sleepable RCU, so the caller must not block between them.
      If the code changes active or inactive dm table, it must call
      dm_sync_table before destroying the old table.
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
  17. 10 May, 2013 1 commit
  18. 01 Mar, 2013 3 commits
    • Alasdair G Kergon's avatar
      dm: add target num_write_bios fn · b0d8ed4d
      Alasdair G Kergon authored
      Add a num_write_bios function to struct target.
      If an instance of a target sets this, it will be queried before the
      target's mapping function is called on a write bio, and the response
      controls the number of copies of the write bio that the target will
      This provides a convenient way for a target to send the same data to
      more than one device.  The new cache target uses this in writethrough
      mode, to send the data both to the cache and the backing device.
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
    • Alasdair G Kergon's avatar
      dm: rename request variables to bios · 55a62eef
      Alasdair G Kergon authored
      Use 'bio' in the name of variables and functions that deal with
      bios rather than 'request' to avoid confusion with the normal
      block layer use of 'request'.
      No functional changes.
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
    • Mikulas Patocka's avatar
      dm: fix truncated status strings · fd7c092e
      Mikulas Patocka authored
      Avoid returning a truncated table or status string instead of setting
      the DM_BUFFER_FULL_FLAG when the last target of a table fills the
      When processing a table or status request, the function retrieve_status
      calls ti->type->status. If ti->type->status returns non-zero,
      retrieve_status assumes that the buffer overflowed and sets
      However, targets don't return non-zero values from their status method
      on overflow. Most targets returns always zero.
      If a buffer overflow happens in a target that is not the last in the
      table, it gets noticed during the next iteration of the loop in
      retrieve_status; but if a buffer overflow happens in the last target, it
      goes unnoticed and erroneously truncated data is returned.
      In the current code, the targets behave in the following way:
      * dm-crypt returns -ENOMEM if there is not enough space to store the
        key, but it returns 0 on all other overflows.
      * dm-thin returns errors from the status method if a disk error happened.
        This is incorrect because retrieve_status doesn't check the error
        code, it assumes that all non-zero values mean buffer overflow.
      * all the other targets always return 0.
      This patch changes the ti->type->status function to return void (because
      most targets don't use the return code). Overflow is detected in
      retrieve_status: if the status method fills up the remaining space
      completely, it is assumed that buffer overflow happened.
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
  19. 21 Dec, 2012 4 commits
  20. 27 Jul, 2012 6 commits
  21. 31 Oct, 2011 4 commits
  22. 25 Sep, 2011 1 commit
    • Milan Broz's avatar
      dm crypt: always disable discard_zeroes_data · 983c7db3
      Milan Broz authored
      If optional discard support in dm-crypt is enabled, discards requests
      bypass the crypt queue and blocks of the underlying device are discarded.
      For the read path, discarded blocks are handled the same as normal
      ciphertext blocks, thus decrypted.
      So if the underlying device announces discarded regions return zeroes,
      dm-crypt must disable this flag because after decryption there is just
      random noise instead of zeroes.
      Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
  23. 02 Aug, 2011 1 commit
  24. 29 May, 2011 1 commit