1. 23 Mar, 2017 4 commits
    • Jan Kara's avatar
      bdi: Unify bdi->wb_list handling for root wb_writeback · e8cb72b3
      Jan Kara authored
      Currently root wb_writeback structure is added to bdi->wb_list in
      bdi_init() and never removed. That is different from all other
      wb_writeback structures which get added to the list when created and
      removed from it before wb_shutdown().
      
      So move list addition of root bdi_writeback to bdi_register() and list
      removal of all wb_writeback structures to wb_shutdown(). That way a
      wb_writeback structure is on bdi->wb_list if and only if it can handle
      writeback and it will make it easier for us to handle shutdown of all
      wb_writeback structures in bdi_unregister().
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      e8cb72b3
    • Jan Kara's avatar
      bdi: Make wb->bdi a proper reference · 810df54a
      Jan Kara authored
      Make wb->bdi a proper refcounted reference to bdi for all bdi_writeback
      structures except for the one embedded inside struct backing_dev_info.
      That will allow us to simplify bdi unregistration.
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      810df54a
    • Jan Kara's avatar
      bdi: Mark congested->bdi as internal · b7d680d7
      Jan Kara authored
      congested->bdi pointer is used only to be able to remove congested
      structure from bdi->cgwb_congested_tree on structure release. Moreover
      the pointer can become NULL when we unregister the bdi. Rename the field
      to __bdi and add a comment to make it more explicit this is internal
      stuff of memcg writeback code and people should not use the field as
      such use will be likely race prone.
      
      We do not bother with converting congested->bdi to a proper refcounted
      reference. It will be slightly ugly to special-case bdi->wb.congested to
      avoid effectively a cyclic reference of bdi to itself and the reference
      gets cleared from bdi_unregister() making it impossible to reference
      a freed bdi.
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      b7d680d7
    • Jan Kara's avatar
      block: Fix bdi assignment to bdev inode when racing with disk delete · 03e26279
      Jan Kara authored
      When disk->fops->open() in __blkdev_get() returns -ERESTARTSYS, we
      restart the process of opening the block device. However we forget to
      switch bdev->bd_bdi back to noop_backing_dev_info and as a result bdev
      inode will be pointing to a stale bdi. Fix the problem by setting
      bdev->bd_bdi later when __blkdev_get() is already guaranteed to succeed.
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      03e26279
  2. 21 Mar, 2017 6 commits
    • Jens Axboe's avatar
      block: fix stacked driver stats init and free · a83b576c
      Jens Axboe authored
      If a driver allocates a queue for stacked usage, then it does
      not currently get stats allocated. This causes the later init
      of, eg, writeback throttling to blow up. Move the init to the
      queue allocation instead.
      
      Additionally, allow a NULL callback unregistration. This avoids
      having the caller check for that, fixing another oops on
      removal of a block device that doesn't have poll stats allocated.
      
      Fixes: 34dbad5d ("blk-stat: convert to callback-based statistics reporting")
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      a83b576c
    • Omar Sandoval's avatar
      blk-stat: convert to callback-based statistics reporting · 34dbad5d
      Omar Sandoval authored
      Currently, statistics are gathered in ~0.13s windows, and users grab the
      statistics whenever they need them. This is not ideal for both in-tree
      users:
      
      1. Writeback throttling wants its own dynamically sized window of
         statistics. Since the blk-stats statistics are reset after every
         window and the wbt windows don't line up with the blk-stats windows,
         wbt doesn't see every I/O.
      2. Polling currently grabs the statistics on every I/O. Again, depending
         on how the window lines up, we may miss some I/Os. It's also
         unnecessary overhead to get the statistics on every I/O; the hybrid
         polling heuristic would be just as happy with the statistics from the
         previous full window.
      
      This reworks the blk-stats infrastructure to be callback-based: users
      register a callback that they want called at a given time with all of
      the statistics from the window during which the callback was active.
      Users can dynamically bucketize the statistics. wbt and polling both
      currently use read vs. write, but polling can be extended to further
      subdivide based on request size.
      
      The callbacks are kept on an RCU list, and each callback has percpu
      stats buffers. There will only be a few users, so the overhead on the
      I/O completion side is low. The stats flushing is also simplified
      considerably: since the timer function is responsible for clearing the
      statistics, we don't have to worry about stale statistics.
      
      wbt is a trivial conversion. After the conversion, the windowing problem
      mentioned above is fixed.
      
      For polling, we register an extra callback that caches the previous
      window's statistics in the struct request_queue for the hybrid polling
      heuristic to use.
      
      Since we no longer have a single stats buffer for the request queue,
      this also removes the sysfs and debugfs stats entries. To replace those,
      we add a debugfs entry for the poll statistics.
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      34dbad5d
    • Omar Sandoval's avatar
      blk-stat: move BLK_RQ_STAT_BATCH definition to blk-stat.c · 4875253f
      Omar Sandoval authored
      This is an implementation detail that no-one outside of blk-stat.c uses.
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      4875253f
    • Omar Sandoval's avatar
      blk-stat: use READ and WRITE instead of BLK_STAT_{READ,WRITE} · fa2e39cb
      Omar Sandoval authored
      The stats buckets will become generic soon, so make the existing users
      use the common READ and WRITE definitions instead of one internal to
      blk-stat.
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      fa2e39cb
    • Omar Sandoval's avatar
      block: remove extra calls to wbt_exit() · 0315b159
      Omar Sandoval authored
      We always call wbt_exit() from blk_release_queue(), so these are
      unnecessary.
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      0315b159
    • Omar Sandoval's avatar
      blk-stat: fix blk_stat_sum() if all samples are batched · 7d8d0014
      Omar Sandoval authored
      We need to flush the batch _before_ we check the number of samples,
      otherwise we'll miss all of the batched samples.
      
      Fixes: cf43e6be ("block: add scalable completion tracking of requests")
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      7d8d0014
  3. 20 Mar, 2017 5 commits
    • Linus Torvalds's avatar
      Linux 4.11-rc3 · 97da3854
      Linus Torvalds authored
      97da3854
    • Linus Torvalds's avatar
      mm/swap: don't BUG_ON() due to uninitialized swap slot cache · 452b94b8
      Linus Torvalds authored
      This BUG_ON() triggered for me once at shutdown, and I don't see a
      reason for the check.  The code correctly checks whether the swap slot
      cache is usable or not, so an uninitialized swap slot cache is not
      actually problematic afaik.
      
      I've temporarily just switched the BUG_ON() to a WARN_ON_ONCE(), since
      I'm not sure why that seemingly pointless check was there.  I suspect
      the real fix is to just remove it entirely, but for now we'll warn about
      it but not bring the machine down.
      
      Cc: "Huang, Ying" <ying.huang@intel.com>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      452b94b8
    • Linus Torvalds's avatar
      Merge tag 'powerpc-4.11-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · a07a6e41
      Linus Torvalds authored
      Pull more powerpc fixes from Michael Ellerman:
       "A couple of minor powerpc fixes for 4.11:
      
         - wire up statx() syscall
      
         - don't print a warning on memory hotplug when HPT resizing isn't
           available
      
        Thanks to: David Gibson, Chandan Rajendra"
      
      * tag 'powerpc-4.11-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
        powerpc/pseries: Don't give a warning when HPT resizing isn't available
        powerpc: Wire up statx() syscall
      a07a6e41
    • Linus Torvalds's avatar
      Merge branch 'parisc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux · 4571bc5a
      Linus Torvalds authored
      Pull parisc fixes from Helge Deller:
      
       - Mikulas Patocka added support for R_PARISC_SECREL32 relocations in
         modules with CONFIG_MODVERSIONS.
      
       - Dave Anglin optimized the cache flushing for vmap ranges.
      
       - Arvind Yadav provided a fix for a potential NULL pointer dereference
         in the parisc perf code (and some code cleanups).
      
       - I wired up the new statx system call, fixed some compiler warnings
         with the access_ok() macro and fixed shutdown code to really halt a
         system at shutdown instead of crashing & rebooting.
      
      * 'parisc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
        parisc: Fix system shutdown halt
        parisc: perf: Fix potential NULL pointer dereference
        parisc: Avoid compiler warnings with access_ok()
        parisc: Wire up statx system call
        parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range
        parisc: support R_PARISC_SECREL32 relocation in modules
      4571bc5a
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending · 8aa34172
      Linus Torvalds authored
      Pull SCSI target fixes from Nicholas Bellinger:
       "The bulk of the changes are in qla2xxx target driver code to address
        various issues found during Cavium/QLogic's internal testing (stable
        CC's included), along with a few other stability and smaller
        miscellaneous improvements.
      
        There are also a couple of different patch sets from Mike Christie,
        which have been a result of his work to use target-core ALUA logic
        together with tcm-user backend driver.
      
        Finally, a patch to address some long standing issues with
        pass-through SCSI export of TYPE_TAPE + TYPE_MEDIUM_CHANGER devices,
        which will make folks using physical (or virtual) magnetic tape happy"
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (28 commits)
        qla2xxx: Update driver version to 9.00.00.00-k
        qla2xxx: Fix delayed response to command for loop mode/direct connect.
        qla2xxx: Change scsi host lookup method.
        qla2xxx: Add DebugFS node to display Port Database
        qla2xxx: Use IOCB interface to submit non-critical MBX.
        qla2xxx: Add async new target notification
        qla2xxx: Export DIF stats via debugfs
        qla2xxx: Improve T10-DIF/PI handling in driver.
        qla2xxx: Allow relogin to proceed if remote login did not finish
        qla2xxx: Fix sess_lock & hardware_lock lock order problem.
        qla2xxx: Fix inadequate lock protection for ABTS.
        qla2xxx: Fix request queue corruption.
        qla2xxx: Fix memory leak for abts processing
        qla2xxx: Allow vref count to timeout on vport delete.
        tcmu: Convert cmd_time_out into backend device attribute
        tcmu: make cmd timeout configurable
        tcmu: add helper to check if dev was configured
        target: fix race during implicit transition work flushes
        target: allow userspace to set state to transitioning
        target: fix ALUA transition timeout handling
        ...
      8aa34172
  4. 19 Mar, 2017 15 commits
  5. 18 Mar, 2017 10 commits
    • Nicholas Bellinger's avatar
      tcmu: Convert cmd_time_out into backend device attribute · 7d7a7435
      Nicholas Bellinger authored
      Instead of putting cmd_time_out under ../target/core/user_0/foo/control,
      which has historically been used by parameters needed for initial
      backend device configuration, go ahead and move cmd_time_out into
      a backend device attribute.
      
      In order to do this, tcmu_module_init() has been updated to create
      a local struct configfs_attribute **tcmu_attrs, that is based upon
      the existing passthrough_attrib_attrs along with the new cmd_time_out
      attribute.  Once **tcm_attrs has been setup, go ahead and point
      it at tcmu_ops->tb_dev_attrib_attrs so it's picked up by target-core.
      
      Also following MNC's previous change, ->cmd_time_out is stored in
      milliseconds but exposed via configfs in seconds.  Also, note this
      patch restricts the modification of ->cmd_time_out to before +
      after the TCMU device has been configured, but not while it has
      active fabric exports.
      
      Cc: Mike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      7d7a7435
    • Mike Christie's avatar
      tcmu: make cmd timeout configurable · af980e46
      Mike Christie authored
      A single daemon could implement multiple types of devices
      using multuple types of real devices that may not support
      restarting from crashes and/or handling tcmu timeouts. This
      makes the cmd timeout configurable, so handlers that do not
      support it can turn if off for now.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      af980e46
    • Mike Christie's avatar
      tcmu: add helper to check if dev was configured · 972c7f16
      Mike Christie authored
      This adds a helper to check if the dev was configured. It
      will be used in the next patch to prevent updates to some
      config settings after the device has been setup.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      972c7f16
    • Linus Torvalds's avatar
      Merge tag 'openrisc-for-linus' of git://github.com/openrisc/linux · 93afaa45
      Linus Torvalds authored
      Pull OpenRISC fixes from Stafford Horne:
       "OpenRISC fixes for build issues that were exposed by kbuild robots
        after 4.11 merge. All from allmodconfig builds. This includes:
      
         - bug in the handling of 8-byte get_user() calls
      
         - module build failure due to multile missing symbol exports"
      
      * tag 'openrisc-for-linus' of git://github.com/openrisc/linux:
        openrisc: Export symbols needed by modules
        openrisc: fix issue handling 8 byte get_user calls
        openrisc: xchg: fix `computed is not used` warning
      93afaa45
    • Mike Christie's avatar
      target: fix race during implicit transition work flushes · 760bf578
      Mike Christie authored
      This fixes the following races:
      
      1. core_alua_do_transition_tg_pt could have read
      tg_pt_gp_alua_access_state and gone into this if chunk:
      
      if (!explicit &&
              atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state) ==
                 ALUA_ACCESS_STATE_TRANSITION) {
      
      and then core_alua_do_transition_tg_pt_work could update the
      state. core_alua_do_transition_tg_pt would then only set
      tg_pt_gp_alua_pending_state and the tg_pt_gp_alua_access_state would
      not get updated with the second calls state.
      
      2. core_alua_do_transition_tg_pt could be setting
      tg_pt_gp_transition_complete while the tg_pt_gp_transition_work
      is already completing. core_alua_do_transition_tg_pt then waits on the
      completion that will never be called.
      
      To handle these issues, we just call flush_work which will return when
      core_alua_do_transition_tg_pt_work has completed so there is no need
      to do the complete/wait. And, if core_alua_do_transition_tg_pt_work
      was running, instead of trying to sneak in the state change, we just
      schedule up another core_alua_do_transition_tg_pt_work call.
      
      Note that this does not handle a possible race where there are multiple
      threads call core_alua_do_transition_tg_pt at the same time. I think
      we need a mutex in target_tg_pt_gp_alua_access_state_store.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      760bf578
    • Mike Christie's avatar
      target: allow userspace to set state to transitioning · 1ca4d4fa
      Mike Christie authored
      Userspace target_core_user handlers like tcmu-runner may want to set the
      ALUA state to transitioning while it does implicit transitions. This
      patch allows that state when set from configfs.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      1ca4d4fa
    • Mike Christie's avatar
      target: fix ALUA transition timeout handling · d7175373
      Mike Christie authored
      The implicit transition time tells initiators the min time
      to wait before timing out a transition. We currently schedule
      the transition to occur in tg_pt_gp_implicit_trans_secs
      seconds so there is no room for delays. If
      core_alua_do_transition_tg_pt_work->core_alua_update_tpg_primary_metadata
      needs to write out info to a remote file, then the initiator can
      easily time out the operation.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      d7175373
    • Mike Christie's avatar
      target: Use system workqueue for ALUA transitions · 207ee841
      Mike Christie authored
      If tcmu-runner is processing a STPG and needs to change the kernel's
      ALUA state then we cannot use the same work queue for task management
      requests and ALUA transitions, because we could deadlock. The problem
      occurs when a STPG times out before tcmu-runner is able to
      call into target_tg_pt_gp_alua_access_state_store->
      core_alua_do_port_transition -> core_alua_do_transition_tg_pt ->
      queue_work. In this case, the tmr is on the work queue waiting for
      the STPG to complete, but the STPG transition is now queued behind
      the waiting tmr.
      
      Note:
      This bug will also be fixed by this patch:
      http://www.spinics.net/lists/target-devel/msg14560.html
      which switches the tmr code to use the system workqueues.
      
      For both, I am not sure if we need a dedicated workqueue since
      it is not a performance path and I do not think we need WQ_MEM_RECLAIM
      to make forward progress to free up memory like the block layer does.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      207ee841
    • Mike Christie's avatar
      target: fail ALUA transitions for pscsi · 0a414572
      Mike Christie authored
      We do not setup the LU group for pscsi devices, so if you write
      a state to alua_access_state that will cause a transition you will
      get a NULL pointer dereference.
      
      This patch will fail attempts to try and transition the path
      for backend devices that set the TRANSPORT_FLAG_PASSTHROUGH_ALUA
      flag.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      0a414572
    • Mike Christie's avatar
      target: allow ALUA setup for some passthrough backends · 530c6891
      Mike Christie authored
      This patch allows passthrough backends to use the core/base LIO
      ALUA setup and state checks, but still handle the execution of
      commands.
      
      This will allow the target_core_user module to execute STPG and RTPG
      in userspace, and not have to duplicate the ALUA state checks, path
      information (needed so we can check if command is executable on
      specific paths) and setup (rtslib sets/updates the configfs ALUA
      interface like it does for iblock or file).
      
      For STPG, the target_core_user userspace daemon, tcmu-runner will
      still execute the STPG, and to update the core/base LIO state it
      will use the existing configfs interface. For RTPG, tcmu-runner
      will loop over configfs and/or cache the state.
      Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      530c6891