1. 15 Jul, 2009 2 commits
  2. 08 Jul, 2009 37 commits
  3. 07 Jul, 2009 1 commit
    • Jiaying Zhang's avatar
      quota: Fix possible deadlock during parallel quotaon and quotaoff · d01730d7
      Jiaying Zhang authored
      The following test script triggers a deadlock on ext2 filesystem:
      while true; do quotaon /dev/hda >&/dev/null; usleep $RANDOM; done &
      while true; do quotaoff /dev/hda >&/dev/null; usleep $RANDOM; done &
      
      I found there is a potential deadlock between quotaon and quotaoff (or
      quotasync). Basically, all of quotactl operations need to be protected by
      dqonoff_mutex. vfs_quota_off and vfs_quota_sync also call sb->s_op->quota_write
      that needs to grab the i_mutex of the quota file.  But in vfs_quota_on_inode
      (called from quotaon operation), the current code tries to grab  the i_mutex of
      the quota file first before getting quonoff_mutex.
      
      Reverse the order in which we take locks in vfs_quota_on_inode().
      
      Jan Kara: Changed changelog to be more readable, made lockdep happy with
        I_MUTEX_QUOTA.
      Signed-off-by: default avatarJiaying Zhang <jiayingz@google.com>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      d01730d7