1. 18 Nov, 2016 7 commits
    • Song Liu's avatar
      md/r5cache: State machine for raid5-cache write back mode · 2ded3703
      Song Liu authored
      This patch adds state machine for raid5-cache. With log device, the
      raid456 array could operate in two different modes (r5c_journal_mode):
        - write-back (R5C_MODE_WRITE_BACK)
        - write-through (R5C_MODE_WRITE_THROUGH)
      
      Existing code of raid5-cache only has write-through mode. For write-back
      cache, it is necessary to extend the state machine.
      
      With write-back cache, every stripe could operate in two different
      phases:
        - caching
        - writing-out
      
      In caching phase, the stripe handles writes as:
        - write to journal
        - return IO
      
      In writing-out phase, the stripe behaviors as a stripe in write through
      mode R5C_MODE_WRITE_THROUGH.
      
      STRIPE_R5C_CACHING is added to sh->state to differentiate caching and
      writing-out phase.
      
      Please note: this is a "no-op" patch for raid5-cache write-through
      mode.
      
      The following detailed explanation is copied from the raid5-cache.c:
      
      /*
       * raid5 cache state machine
       *
       * With rhe RAID cache, each stripe works in two phases:
       *      - caching phase
       *      - writing-out phase
       *
       * These two phases are controlled by bit STRIPE_R5C_CACHING:
       *   if STRIPE_R5C_CACHING == 0, the stripe is in writing-out phase
       *   if STRIPE_R5C_CACHING == 1, the stripe is in caching phase
       *
       * When there is no journal, or the journal is in write-through mode,
       * the stripe is always in writing-out phase.
       *
       * For write-back journal, the stripe is sent to caching phase on write
       * (r5c_handle_stripe_dirtying). r5c_make_stripe_write_out() kicks off
       * the write-out phase by clearing STRIPE_R5C_CACHING.
       *
       * Stripes in caching phase do not write the raid disks. Instead, all
       * writes are committed from the log device. Therefore, a stripe in
       * caching phase handles writes as:
       *      - write to log device
       *      - return IO
       *
       * Stripes in writing-out phase handle writes as:
       *      - calculate parity
       *      - write pending data and parity to journal
       *      - write data and parity to raid disks
       *      - return IO for pending writes
       */
      Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      2ded3703
    • Song Liu's avatar
      md/r5cache: move some code to raid5.h · 937621c3
      Song Liu authored
      Move some define and inline functions to raid5.h, so they can be
      used in raid5-cache.c
      Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      937621c3
    • Song Liu's avatar
      md/r5cache: Check array size in r5l_init_log · c757ec95
      Song Liu authored
      Currently, r5l_write_stripe checks meta size for each stripe write,
      which is not necessary.
      
      With this patch, r5l_init_log checks maximal meta size of the array,
      which is (r5l_meta_block + raid_disks x r5l_payload_data_parity).
      If this is too big to fit in one page, r5l_init_log aborts.
      
      With current meta data, r5l_log support raid_disks up to 203.
      Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      c757ec95
    • Shaohua Li's avatar
      md: add blktrace event for writes to superblock · 504634f6
      Shaohua Li authored
      superblock write is an expensive operation. With raid5-cache, it can be called
      regularly. Tracing to help performance debug.
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      Cc: NeilBrown <neilb@suse.com>
      504634f6
    • NeilBrown's avatar
      md/raid1, raid10: add blktrace records when IO is delayed · 578b54ad
      NeilBrown authored
      Both raid1 and raid10 will sometimes delay handling an IO request,
      such as when resync is happening or there are too many requests queued.
      
      Add some blktrace messsages so we can see when that is happening when
      looking for performance artefacts.
      Signed-off-by: default avatarNeilBrown <neilb@suse.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      578b54ad
    • NeilBrown's avatar
      md/bitmap: add blktrace event for writes to the bitmap · 581dbd94
      NeilBrown authored
      We trace wheneven bitmap_unplug() finds that it needs to write
      to the bitmap, or when bitmap_daemon_work() find there is work
      to do.
      
      This makes it easier to correlate bitmap updates with data writes.
      Signed-off-by: default avatarNeilBrown <neilb@suse.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      581dbd94
    • NeilBrown's avatar
      md: add block tracing for bio_remapping · 109e3765
      NeilBrown authored
      The block tracing infrastructure (accessed with blktrace/blkparse)
      supports the tracing of mapping bios from one device to another.
      This is currently used when a bio in a partition is mapped to the
      whole device, when bios are mapped by dm, and for mapping in md/raid5.
      Other md personalities do not include this tracing yet, so add it.
      
      When a read-error is detected we redirect the request to a different device.
      This could justifiably be seen as a new mapping for the originial bio,
      or a secondary mapping for the bio that errors.  This patch uses
      the second option.
      
      When md is used under dm-raid, the mappings are not traced as we do
      not have access to the block device number of the parent.
      Signed-off-by: default avatarNeilBrown <neilb@suse.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      109e3765
  2. 17 Nov, 2016 1 commit
  3. 10 Nov, 2016 1 commit
  4. 09 Nov, 2016 2 commits
    • NeilBrown's avatar
      md: define mddev flags, recovery flags and r1bio state bits using enums · be306c29
      NeilBrown authored
      This is less error prone than using individual #defines.
      Signed-off-by: default avatarNeilBrown <neilb@suse.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      be306c29
    • NeilBrown's avatar
      md/raid1: fix: IO can block resync indefinitely · f2c771a6
      NeilBrown authored
      While performing a resync/recovery, raid1 divides the
      array space into three regions:
       - before the resync
       - at or shortly after the resync point
       - much further ahead of the resync point.
      
      Write requests to the first or third do not need to wait.  Write
      requests to the middle region do need to wait if resync requests are
      pending.
      
      If there are any active write requests in the middle region, resync
      will wait for them.
      
      Due to an accounting error, there is a small range of addresses,
      between conf->next_resync and conf->start_next_window, where write
      requests will *not* be blocked, but *will* be counted in the middle
      region.  This can effectively block resync indefinitely if filesystem
      writes happen repeatedly to this region.
      
      As ->next_window_requests is incremented when the sector is after
        conf->start_next_window + NEXT_NORMALIO_DISTANCE
      the same boundary should be used for determining when write requests
      should wait.
      Signed-off-by: default avatarNeilBrown <neilb@suse.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      f2c771a6
  5. 07 Nov, 2016 24 commits
  6. 06 Nov, 2016 1 commit
    • Guenter Roeck's avatar
      openrisc: Define __ro_after_init to avoid crash · 2c7a5c5c
      Guenter Roeck authored
      openrisc qemu tests fail with the following crash.
      
      Unable to handle kernel access at virtual address 0xc0300c34
      
      Oops#: 0001
      CPU #: 0
         PC: c016c710    SR: 0000ae67    SP: c1017e04
         GPR00: 00000000 GPR01: c1017e04 GPR02: c0300c34 GPR03: c0300c34
         GPR04: 00000000 GPR05: c0300cb0 GPR06: c0300c34 GPR07: 000000ff
         GPR08: c107f074 GPR09: c0199ef4 GPR10: c1016000 GPR11: 00000000
         GPR12: 00000000 GPR13: c107f044 GPR14: c0473774 GPR15: 07ce0000
         GPR16: 00000000 GPR17: c107ed8a GPR18: 00009600 GPR19: c107f044
         GPR20: c107ee74 GPR21: 00000003 GPR22: c0473770 GPR23: 00000033
         GPR24: 000000bf GPR25: 00000019 GPR26: c046400c GPR27: 00000001
         GPR28: c0464028 GPR29: c1018000 GPR30: 00000006 GPR31: ccf37483
           RES: 00000000 oGPR11: ffffffff
           Process swapper (pid: 1, stackpage=c1001960)
      
           Stack: Stack dump [0xc1017cf8]:
           sp + 00: 0xc1017e04
           sp + 04: 0xc0300c34
           sp + 08: 0xc0300c34
           sp + 12: 0x00000000
      ...
      
      Bisect points to commit d2ec3f77 ("pty: make ptmx file ops read-only
      after init"). Fix by defining __ro_after_init for the openrisc
      architecture, similar to parisc.
      
      Fixes: d2ec3f77 ("pty: make ptmx file ops read-only after init")
      Cc: Kees Cook <keescook@chromium.org>
      Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Acked-by: default avatarStafford Horne <shorne@gmail.com>
      2c7a5c5c
  7. 05 Nov, 2016 4 commits