1. 09 Nov, 2013 10 commits
  2. 05 Nov, 2013 2 commits
    • Joe Thornber's avatar
      dm array: fix bug in growing array · 9c1d4de5
      Joe Thornber authored
      Entries would be lost if the old tail block was partially filled.
      Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Cc: stable@vger.kernel.org # 3.9+
      9c1d4de5
    • Hannes Reinecke's avatar
      dm mpath: requeue I/O during pg_init · b63349a7
      Hannes Reinecke authored
      When pg_init is running no I/O can be submitted to the underlying
      devices, as the path priority etc might change.  When using queue_io for
      this, requests will be piling up within multipath as the block I/O
      scheduler just sees a _very fast_ device.  All of this queued I/O has to
      be resubmitted from within multipathing once pg_init is done.
      
      This approach has the problem that it's virtually impossible to
      abort I/O when pg_init is running, and we're adding heavy load
      to the devices after pg_init since all of the queued I/O needs to be
      resubmitted _before_ any requests can be pulled off of the request queue
      and normal operation continues.
      
      This patch will requeue the I/O that triggers the pg_init call, and
      return 'busy' when pg_init is in progress.  With these changes the block
      I/O scheduler will stop submitting I/O during pg_init, resulting in a
      quicker path switch and less I/O pressure (and memory consumption) after
      pg_init.
      Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
      [patch header edited for clarity and typos by Mike Snitzer]
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      b63349a7
  3. 01 Nov, 2013 1 commit
    • Shiva Krishna Merla's avatar
      dm mpath: fix race condition between multipath_dtr and pg_init_done · 954a73d5
      Shiva Krishna Merla authored
      Whenever multipath_dtr() is happening we must prevent queueing any
      further path activation work.  Implement this by adding a new
      'pg_init_disabled' flag to the multipath structure that denotes future
      path activation work should be skipped if it is set.  By disabling
      pg_init and then re-enabling in flush_multipath_work() we also avoid the
      potential for pg_init to be initiated while suspending an mpath device.
      
      Without this patch a race condition exists that may result in a kernel
      panic:
      
      1) If after pg_init_done() decrements pg_init_in_progress to 0, a call
         to wait_for_pg_init_completion() assumes there are no more pending path
         management commands.
      2) If pg_init_required is set by pg_init_done(), due to retryable
         mode_select errors, then process_queued_ios() will again queue the
         path activation work.
      3) If free_multipath() completes before activate_path() work is called a
         NULL pointer dereference like the following can be seen when
         accessing members of the recently destructed multipath:
      
      BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
      RIP: 0010:[<ffffffffa003db1b>]  [<ffffffffa003db1b>] activate_path+0x1b/0x30 [dm_multipath]
      [<ffffffff81090ac0>] worker_thread+0x170/0x2a0
      [<ffffffff81096c80>] ? autoremove_wake_function+0x0/0x40
      
      [switch to disabling pg_init in flush_multipath_work & header edits by Mike Snitzer]
      Signed-off-by: default avatarShiva Krishna Merla <shivakrishna.merla@netapp.com>
      Reviewed-by: default avatarKrishnasamy Somasundaram <somasundaram.krishnasamy@netapp.com>
      Tested-by: default avatarSpeagle Andy <Andy.Speagle@netapp.com>
      Acked-by: default avatarJunichi Nomura <j-nomura@ce.jp.nec.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Cc: stable@vger.kernel.org
      954a73d5
  4. 31 Oct, 2013 1 commit
  5. 13 Oct, 2013 17 commits
  6. 12 Oct, 2013 9 commits