1. 16 Oct, 2017 6 commits
    • Eric Wheeler's avatar
      bcache: update bio->bi_opf bypass/writeback REQ_ flag hints · b41c9b02
      Eric Wheeler authored
      Flag for bypass if the IO is for read-ahead or background, unless the
      read-ahead request is for metadata (eg, from gfs2).
              Bypass if:
                      bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) &&
      			!(bio->bi_opf & REQ_META))
      
              Writeback if:
                      op_is_sync(bio->bi_opf) ||
      			bio->bi_opf & (REQ_META|REQ_PRIO)
      Signed-off-by: default avatarEric Wheeler <bcache@linux.ewheeler.net>
      Reviewed-by: default avatarColy Li <colyli@suse.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      b41c9b02
    • Yijing Wang's avatar
      bcache: Remove redundant set_capacity · e89d6759
      Yijing Wang authored
      set_capacity() has been called in bcache_device_init(),
      remove the redundant one.
      Signed-off-by: default avatarYijing Wang <wangyijing@huawei.com>
      Reviewed-by: default avatarEric Wheeler <bcache@linux.ewheeler.net>
      Acked-by: default avatarColy Li <colyli@suse.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      e89d6759
    • Coly Li's avatar
      bcache: rewrite multiple partitions support · 1dbe32ad
      Coly Li authored
      Current partition support of bcache is confusing and buggy. It tries to
      trace non-continuous device minor numbers by an ida bit string, and
      mistakenly mixed bcache device index with minor numbers. This design
      generates several negative results,
      - Index of bcache device name is not consecutive under /dev/. If there are
        3 bcache devices, they name will be,
        /dev/bcache0, /dev/bcache16, /dev/bcache32
        Only bcache code indexes bcache device name is such an interesting way.
      - First minor number of each bcache device is traced by ida bit string.
        One bcache device will occupy 16 bits, this is not a good idea. Indeed
        only one bit is enough.
      - Because minor number and bcache device index are mixed, a device index
        is allocated by ida_simple_get(), but an first minor number is sent into
        ida_simple_remove() to release the device. It confused original author
        too.
      
      Root cause of the above errors is, bcache code should not handle device
      minor numbers at all! A standard process to support multiple partitions in
      Linux kernel is,
      - Device driver provides major device number, and indexes multiple device
        instances.
      - Device driver does not allocat nor trace device minor number, only
        provides a first minor number of a given device instance, and sets how
        many minor numbers (paritions) the device instance may have.
      All rested stuffs are handled by block layer code, most of the details can
      be found from block/{genhd, partition-generic}.c files.
      
      This patch re-writes multiple partitions support for bcache. It makes
      whole things to be more clear, and uses ida bit string in a more efficeint
      way.
      - Ida bit string only traces bcache device index, not minor number. For a
        bcache device with 128 partitions, only one bit in ida bit string is
        enough.
      - Device minor number and device index are separated in concept. Device
        index is used for /dev node naming, and ida bit string trace. Minor
        number is calculated from device index and only used to initialize
        first_minor of a bcache device.
      - It does not follow any standard for 16 partitions on a bcache device.
        This patch sets 128 partitions on single bcache device at max, this is
        the limitation from GPT (GUID Partition Table) and supported by fdisk.
      
      Considering a typical device minor number is 20 bits width, each bcache
      device may have 128 partitions (7 bits), there can be 8192 bcache devices
      existing on system. For most common deployment for a single server in
      now days, it should be enough.
      
      [minor spelling fixes in commit message by Michael Lyle]
      Signed-off-by: default avatarColy Li <colyli@suse.de>
      Cc: Eric Wheeler <bcache@lists.ewheeler.net>
      Cc: Junhui Tang <tang.junhui@zte.com.cn>
      Reviewed-by: default avatarMichael Lyle <mlyle@lyle.org>
      Signed-off-by: default avatarMichael Lyle <mlyle@lyle.org>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      1dbe32ad
    • Coly Li's avatar
      bcache: fix a comments typo in bch_alloc_sectors() · b1e8139e
      Coly Li authored
      Code comments in alloc.c:bch_alloc_sectors() mentions a function
      name find_data_bucket(), the correct function name should be
      pick_data_bucket() indeed. bch_alloc_sectors() is a quite important
      function in bcache allocation code, fixing the typo may help
      other people to have less confusion.
      Signed-off-by: default avatarColy Li <colyli@suse.de>
      Reviewed-by: default avatarTang Junhui <tang.junhui@zte.com.cn>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      b1e8139e
    • Coly Li's avatar
      bcache: check ca->alloc_thread initialized before wake up it · 91af8300
      Coly Li authored
      In bcache code, sysfs entries are created before all resources get
      allocated, e.g. allocation thread of a cache set.
      
      There is posibility for NULL pointer deference if a resource is accessed
      but which is not initialized yet. Indeed Jorg Bornschein catches one on
      cache set allocation thread and gets a kernel oops.
      
      The reason for this bug is, when bch_bucket_alloc() is called during
      cache set registration and attaching, ca->alloc_thread is not properly
      allocated and initialized yet, call wake_up_process() on ca->alloc_thread
      triggers NULL pointer deference failure. A simple and fast fix is, before
      waking up ca->alloc_thread, checking whether it is allocated, and only
      wake up ca->alloc_thread when it is not NULL.
      Signed-off-by: default avatarColy Li <colyli@suse.de>
      Reported-by: default avatarJorg Bornschein <jb@capsec.org>
      Cc: Kent Overstreet <kent.overstreet@gmail.com>
      Cc: stable@vger.kernel.org
      Reviewed-by: default avatarMichael Lyle <mlyle@lyle.org>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      91af8300
    • Peter Foley's avatar
      bcache: Avoid nested function definition · 58f913dc
      Peter Foley authored
      Fixes below error with clang:
      ../drivers/md/bcache/sysfs.c:759:3: error: function definition is not allowed here
                      {       return *((uint16_t *) r) - *((uint16_t *) l); }
                      ^
      ../drivers/md/bcache/sysfs.c:789:32: error: use of undeclared identifier 'cmp'
                      sort(p, n, sizeof(uint16_t), cmp, NULL);
                                                   ^
      2 errors generated.
      
      v2:
      rename function to __bch_cache_cmp
      Signed-off-by: default avatarPeter Foley <pefoley2@pefoley.com>
      Reviewed-by: default avatarColy Li <colyli@suse.de>
      Reviewed-by: default avatarMichael Lyle <mlyle@lyle.org>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      58f913dc
  2. 14 Oct, 2017 1 commit
  3. 13 Oct, 2017 33 commits