1. 20 Jul, 2012 3 commits
    • Mikulas Patocka's avatar
      dm raid1: set discard_zeroes_data_unsupported · 7c8d3a42
      Mikulas Patocka authored
      We can't guarantee that REQ_DISCARD on dm-mirror zeroes the data even if
      the underlying disks support zero on discard.  So this patch sets
      ti->discard_zeroes_data_unsupported.
      
      For example, if the mirror is in the process of resynchronizing, it may
      happen that kcopyd reads a piece of data, then discard is sent on the
      same area and then kcopyd writes the piece of data to another leg.
      Consequently, the data is not zeroed.
      
      The flag was made available by commit 983c7db3
      (dm crypt: always disable discard_zeroes_data).
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Cc: stable@kernel.org
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      7c8d3a42
    • Mikulas Patocka's avatar
      dm thin: do not send discards to shared blocks · 650d2a06
      Mikulas Patocka authored
      When process_discard receives a partial discard that doesn't cover a
      full block, it sends this discard down to that block. Unfortunately, the
      block can be shared and the discard would corrupt the other snapshots
      sharing this block.
      
      This patch detects block sharing and ends the discard with success when
      sending it to the shared block.
      
      The above change means that if the device supports discard it can't be
      guaranteed that a discard request zeroes data. Therefore, we set
      ti->discard_zeroes_data_unsupported.
      
      Thin target discard support with this bug arrived in commit
      104655fd (dm thin: support discards).
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Cc: stable@kernel.org
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      650d2a06
    • Mikulas Patocka's avatar
      dm raid1: fix crash with mirror recovery and discard · 751f188d
      Mikulas Patocka authored
      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
      5fc2ffea (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/837607Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Cc: stable@kernel.org
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      751f188d
  2. 14 Jul, 2012 11 commits
  3. 13 Jul, 2012 19 commits
  4. 12 Jul, 2012 5 commits
  5. 11 Jul, 2012 2 commits
    • Linus Torvalds's avatar
      Merge tag 'fbdev-fixes-for-3.5-2' of git://github.com/schandinat/linux-2.6 · 918227bb
      Linus Torvalds authored
      Pull fbdev fixes from Florian Tobias Schandinat:
       "Two fixes for OMAPDSS by Tomi Valkeinen:
         - one to avoid warnings when runtime PM is not enabled
         - one workaround to dependancy issues during suspend/resume"
      
      * tag 'fbdev-fixes-for-3.5-2' of git://github.com/schandinat/linux-2.6:
        OMAPDSS: fix warnings if CONFIG_PM_RUNTIME=n
        OMAPDSS: Use PM notifiers for system suspend
      918227bb
    • Linus Torvalds's avatar
      Merge branch 'akpm' (Andrew's patch-bomb) · 00c3e276
      Linus Torvalds authored
      Merge random patches from Andrew Morton.
      
      * Merge emailed patches from Andrew Morton <akpm@linux-foundation.org>: (32 commits)
        memblock: free allocated memblock_reserved_regions later
        mm: sparse: fix usemap allocation above node descriptor section
        mm: sparse: fix section usemap placement calculation
        xtensa: fix incorrect memset
        shmem: cleanup shmem_add_to_page_cache
        shmem: fix negative rss in memcg memory.stat
        tmpfs: revert SEEK_DATA and SEEK_HOLE
        drivers/rtc/rtc-twl.c: fix threaded IRQ to use IRQF_ONESHOT
        fat: fix non-atomic NFS i_pos read
        MAINTAINERS: add OMAP CPUfreq driver to OMAP Power Management section
        sgi-xp: nested calls to spin_lock_irqsave()
        fs: ramfs: file-nommu: add SetPageUptodate()
        drivers/rtc/rtc-mxc.c: fix irq enabled interrupts warning
        mm/memory_hotplug.c: release memory resources if hotadd_new_pgdat() fails
        h8300/uaccess: add mising __clear_user()
        h8300/uaccess: remove assignment to __gu_val in unhandled case of get_user()
        h8300/time: add missing #include <asm/irq_regs.h>
        h8300/signal: fix typo "statis"
        h8300/pgtable: add missing #include <asm-generic/pgtable.h>
        drivers/rtc/rtc-ab8500.c: ensure correct probing of the AB8500 RTC when Device Tree is enabled
        ...
      00c3e276