1. 06 Jan, 2009 23 commits
  2. 05 Jan, 2009 17 commits
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm · 238c6d54
      Linus Torvalds authored
      * git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
        dm snapshot: extend exception store functions
        dm snapshot: split out exception store implementations
        dm snapshot: rename struct exception_store
        dm snapshot: separate out exception store interface
        dm mpath: move trigger_event to system workqueue
        dm: add name and uuid to sysfs
        dm table: rework reference counting
        dm: support barriers on simple devices
        dm request: extend target interface
        dm request: add caches
        dm ioctl: allow dm_copy_name_and_uuid to return only one field
        dm log: ensure log bitmap fits on log device
        dm log: move region_size validation
        dm log: avoid reinitialising io_req on every operation
        dm: consolidate target deregistration error handling
        dm raid1: fix error count
        dm log: fix dm_io_client leak on error paths
        dm snapshot: change yield to msleep
        dm table: drop reference at unbind
      238c6d54
    • Jonathan Brassow's avatar
      dm snapshot: extend exception store functions · a159c1ac
      Jonathan Brassow authored
      Supply dm_add_exception as a callback to the read_metadata function.
      Add a status function ready for a later patch and name the functions
      consistently.
      Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      a159c1ac
    • Alasdair G Kergon's avatar
      dm snapshot: split out exception store implementations · 4db6bfe0
      Alasdair G Kergon authored
      Move the existing snapshot exception store implementations out into
      separate files.  Later patches will place these behind a new
      interface in preparation for alternative implementations.
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      4db6bfe0
    • Jonathan Brassow's avatar
      dm snapshot: rename struct exception_store · 1ae25f9c
      Jonathan Brassow authored
      Rename struct exception_store to dm_exception_store.
      Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      1ae25f9c
    • Jonathan Brassow's avatar
      dm snapshot: separate out exception store interface · aea53d92
      Jonathan Brassow authored
      Pull structures that bridge the gap between snapshot and
      exception store out of dm-snap.h and put them in a new
      .h file - dm-exception-store.h.  This file will define the
      API for new exception stores.
      
      Ultimately, dm-snap.h is unnecessary, since only dm-snap.c
      should be using it.
      Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      aea53d92
    • Alasdair G Kergon's avatar
      dm mpath: move trigger_event to system workqueue · fe9cf30e
      Alasdair G Kergon authored
      The same workqueue is used both for sending uevents and processing queued I/O.
      Deadlock has been reported in RHEL5 when sending a uevent was blocked waiting
      for the queued I/O to be processed.  Use scheduled_work() for the asynchronous
      uevents instead.
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      fe9cf30e
    • Milan Broz's avatar
      dm: add name and uuid to sysfs · 784aae73
      Milan Broz authored
      Implement simple read-only sysfs entry for device-mapper block device.
      
      This patch adds a simple sysfs directory named "dm" under block device
      properties and implements
      	- name attribute (string containing mapped device name)
      	- uuid attribute (string containing UUID, or empty string if not set)
      
      The kobject is embedded in mapped_device struct, so no additional
      memory allocation is needed for initializing sysfs entry.
      
      During the processing of sysfs attribute we need to lock mapped device
      which is done by a new function dm_get_from_kobj, which returns the md
      associated with kobject and increases the usage count.
      
      Each 'show attribute' function is responsible for its own locking.
      Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      784aae73
    • Mikulas Patocka's avatar
      dm table: rework reference counting · d5816876
      Mikulas Patocka authored
      Rework table reference counting.
      
      The existing code uses a reference counter. When the last reference is
      dropped and the counter reaches zero, the table destructor is called.
      Table reference counters are acquired/released from upcalls from other
      kernel code (dm_any_congested, dm_merge_bvec, dm_unplug_all).
      If the reference counter reaches zero in one of the upcalls, the table
      destructor is called from almost random kernel code.
      
      This leads to various problems:
      * dm_any_congested being called under a spinlock, which calls the
        destructor, which calls some sleeping function.
      * the destructor attempting to take a lock that is already taken by the
        same process.
      * stale reference from some other kernel code keeps the table
        constructed, which keeps some devices open, even after successful
        return from "dmsetup remove". This can confuse lvm and prevent closing
        of underlying devices or reusing device minor numbers.
      
      The patch changes reference counting so that the table destructor can be
      called only at predetermined places.
      
      The table has always exactly one reference from either mapped_device->map
      or hash_cell->new_map. After this patch, this reference is not counted
      in table->holders.  A pair of dm_create_table/dm_destroy_table functions
      is used for table creation/destruction.
      
      Temporary references from the other code increase table->holders. A pair
      of dm_table_get/dm_table_put functions is used to manipulate it.
      
      When the table is about to be destroyed, we wait for table->holders to
      reach 0. Then, we call the table destructor.  We use active waiting with
      msleep(1), because the situation happens rarely (to one user in 5 years)
      and removing the device isn't performance-critical task: the user doesn't
      care if it takes one tick more or not.
      
      This way, the destructor is called only at specific points
      (dm_table_destroy function) and the above problems associated with lazy
      destruction can't happen.
      
      Finally remove the temporary protection added to dm_any_congested().
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      d5816876
    • Andi Kleen's avatar
      dm: support barriers on simple devices · ab4c1424
      Andi Kleen authored
      Implement barrier support for single device DM devices
      
      This patch implements barrier support in DM for the common case of dm linear
      just remapping a single underlying device. In this case we can safely
      pass the barrier through because there can be no reordering between
      devices.
      
       NB. Any DM device might cease to support barriers if it gets
           reconfigured so code must continue to allow for a possible
           -EOPNOTSUPP on every barrier bio submitted.  - agk
      Signed-off-by: default avatarAndi Kleen <ak@suse.de>
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      ab4c1424
    • Kiyoshi Ueda's avatar
      dm request: extend target interface · 7d76345d
      Kiyoshi Ueda authored
      This patch adds the following target interfaces for request-based dm.
      
        map_rq    : for mapping a request
      
        rq_end_io : for finishing a request
      
        busy      : for avoiding performance regression from bio-based dm.
                    Target can tell dm core not to map requests now, and
                    that may help requests in the block layer queue to be
                    bigger by I/O merging.
                    In bio-based dm, this behavior is done by device
                    drivers managing the block layer queue.
                    But in request-based dm, dm core has to do that
                    since dm core manages the block layer queue.
      Signed-off-by: default avatarKiyoshi Ueda <k-ueda@ct.jp.nec.com>
      Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      7d76345d
    • Kiyoshi Ueda's avatar
      dm request: add caches · 8fbf26ad
      Kiyoshi Ueda authored
      This patch prepares some kmem_caches for request-based dm.
      Signed-off-by: default avatarKiyoshi Ueda <k-ueda@ct.jp.nec.com>
      Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      8fbf26ad
    • Milan Broz's avatar
      dm ioctl: allow dm_copy_name_and_uuid to return only one field · 23d39f63
      Milan Broz authored
      Allow NULL buffer in dm_copy_name_and_uuid if you only want to return one of
      the fields.
      
      (Required by a following patch that adds these fields to sysfs.)
      Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
      Reviewed-by: default avatarAlasdair G Kergon <agk@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      23d39f63
    • Milan Broz's avatar
      dm log: ensure log bitmap fits on log device · ac1f0ac2
      Milan Broz authored
      Check that the log bitmap will fit within the log device.
      Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      ac1f0ac2
    • Milan Broz's avatar
      dm log: move region_size validation · 2045e88e
      Milan Broz authored
      Move log size validation from mirror target to log constructor.
      
      Removed PAGE_SIZE restriction we no longer think necessary.
      Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      2045e88e
    • Takahiro Yasui's avatar
      dm log: avoid reinitialising io_req on every operation · 6f3af01c
      Takahiro Yasui authored
      rw_header function updates three members of io_req data every time
      when I/O is processed. bi_rw and notify.fn are never modified once
      they get initialized, and so they can be set in advance.
      
      header_to_disk() can also be pulled out of write_header() since only one
      caller needs it and write_header() can be replaced by rw_header()
      directly.
      Signed-off-by: default avatarTakahiro Yasui <tyasui@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      6f3af01c
    • Mikulas Patocka's avatar
      dm: consolidate target deregistration error handling · 10d3bd09
      Mikulas Patocka authored
      Change dm_unregister_target to return void and use BUG() for error
      reporting.
      
      dm_unregister_target can only fail because of programming bug in the
      target driver. It can't fail because of user's behavior or disk errors.
      
      This patch changes unregister_target to return void and use BUG if
      someone tries to unregister non-registered target or unregister target
      that is in use.
      
      This patch removes code duplication (testing of error codes in all dm
      targets) and reports bugs in just one place, in dm_unregister_target. In
      some target drivers, these return codes were ignored, which could lead
      to a situation where bugs could be missed.
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      10d3bd09
    • Jonathan Brassow's avatar
      dm raid1: fix error count · d460c65a
      Jonathan Brassow authored
      Always increase the error count when I/O on a leg of a mirror fails.
      
      The error count is used to decide whether to select an alternative
      mirror leg.  If the target doesn't use the "handle_errors" feature, the
      error count is not updated and the bio can get requeued forever by the
      read callback.
      
      Fix it by increasing error_count before the handle_errors feature
      checking.
      
      Cc: stable@kernel.org
      Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
      Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      d460c65a