01 Feb, 2011

1 commit

  • ocfs2_quota_wq is not depended upon during memory reclaim and, with
    cmwq, there's no reason to use a dedicated workqueue. Drop
    ocfs2_quota_wq and use system_wq instead. dqi_sync_work is already
    sync canceled on quota disable and no further synchronization is
    necessary.

    This change makes ocfs2_quota_setup/shutdown() noops. Both functions
    removed.

    Signed-off-by: Tejun Heo
    Cc: Mark Fasheh
    Cc: Joel Becker

    Tejun Heo
     

22 May, 2010

4 commits

  • commit_dqblk() can write quota info to global file. That is actually a bad
    thing to do because if we are just modifying local quota file, we are not
    prepared (do not hold proper locks, do not have transaction credits) to do
    a modification of the global quota file. So do not use commit_dqblk() and
    instead call our writing function directly.

    Acked-by: Joel Becker
    Signed-off-by: Jan Kara

    Jan Kara
     
  • OCFS2 had three issues with quota locking:
    a) When reading dquot from global quota file, we started a transaction while
    holding dqio_mutex which is prone to deadlocks because other paths do it
    the other way around
    b) During ocfs2_sync_dquot we were not protected against concurrent writers
    on the same node. Because we first copy data to local buffer, a race
    could happen resulting in old data being written to global quota file and
    thus causing quota inconsistency after a crash.
    c) ip_alloc_sem of quota files was acquired while a transaction is started
    in ocfs2_quota_write which can deadlock because we first get ip_alloc_sem
    and then start a transaction when extending quota files.

    We fix the problem a) by pulling all necessary code to ocfs2_acquire_dquot
    and ocfs2_release_dquot. Thus we no longer depend on generic dquot_acquire
    to do the locking and can force proper lock ordering.

    Problems b) and c) are fixed by locking i_mutex and ip_alloc_sem of
    global quota file in ocfs2_lock_global_qf and removing ip_alloc_sem from
    ocfs2_quota_read and ocfs2_quota_write.

    Acked-by: Joel Becker
    Signed-off-by: Jan Kara

    Jan Kara
     
  • The position of global quota file info does not change. So we do not have
    to do logical -> physical block translation every time we reread it from
    disk. Thus we can also avoid taking ip_alloc_sem.

    Acked-by: Joel Becker
    Signed-off-by: Jan Kara

    Jan Kara
     
  • There is no need to map offset of local dquot structure to on disk block
    in each quota write. It is enough to map it just once and store the physical
    block number in quota structure in memory. Moreover this simplifies locking
    as we do not have to take ip_alloc_sem from quota write path.

    Acked-by: Joel Becker
    Signed-off-by: Jan Kara

    Jan Kara
     

10 Dec, 2009

1 commit


22 Sep, 2009

1 commit


24 Jul, 2009

1 commit

  • syncjiff is just a converted value of syncms. Some places which
    are updating syncms forgot to update syncjiff as well. Since the
    conversion is just a simple division / multiplication and it does
    not happen frequently, just remove the syncjiff field to avoid
    forgotten conversions.

    Signed-off-by: Jan Kara
    Signed-off-by: Joel Becker

    Jan Kara
     

06 Jan, 2009

4 commits

  • ocfs2_bread() has become ocfs2_read_virt_blocks(), with a prototype to
    match ocfs2_read_blocks(). The quota code, converting from
    ocfs2_bread(), wraps the call to ocfs2_read_virt_blocks() in
    ocfs2_read_quota_block(). Unfortunately, the prototype of
    ocfs2_read_quota_block() matches the old prototype of ocfs2_bread().

    The problem is that ocfs2_bread() returned the buffer head, and callers
    assumed that a NULL pointer was indicative of error. It wasn't. This
    is why ocfs2_bread() took an int*err argument as well.

    The new prototype of ocfs2_read_virt_blocks() avoids this error handling
    confusion. Let's change ocfs2_read_quota_block() to match.

    Signed-off-by: Joel Becker
    Acked-by: Jan Kara
    Signed-off-by: Mark Fasheh

    Joel Becker
     
  • Implement functions for recovery after a crash. Functions just
    read local quota file and sync info to global quota file.

    Signed-off-by: Jan Kara
    Signed-off-by: Mark Fasheh

    Jan Kara
     
  • This patch creates a work queue for periodic syncing of locally cached quota
    information to the global quota files. We constantly queue a delayed work
    item, to get the periodic behavior.

    Signed-off-by: Mark Fasheh
    Acked-by: Jan Kara

    Mark Fasheh
     
  • For each quota type each node has local quota file. In this file it stores
    changes users have made to disk usage via this node. Once in a while this
    information is synced to global file (and thus with other nodes) so that
    limits enforcement at least aproximately works.

    Global quota files contain all the information about usage and limits. It's
    mostly handled by the generic VFS code (which implements a trie of structures
    inside a quota file). We only have to provide functions to convert structures
    from on-disk format to in-memory one. We also have to provide wrappers for
    various quota functions starting transactions and acquiring necessary cluster
    locks before the actual IO is really started.

    Signed-off-by: Jan Kara
    Signed-off-by: Mark Fasheh

    Jan Kara