cvs commit: src/sys/ufs/ffs ffs_softdep.c

[Don Lewis]

truckman    2005-10-08 05:57:40 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_5)
    sys/ufs/ffs          ffs_softdep.c 
  Log:
  MFC ffs_softdep.c 1.185 - Schedule update of parent directory's link count
                            after rmdir()
  
  Original commit message:
    truckman    2005-09-29 21:50:26 UTC
  
      FreeBSD src repository
  
      Modified files:
        sys/ufs/ffs          ffs_softdep.c
      Log:
      After a rmdir()ed directory has been truncated, force an update of
      the directory's inode after queuing the dirrem that will decrement
      the parent directory's link count.  This will force the update of
      the parent directory's actual link to actually be scheduled.  Without
      this change the parent directory's actual link count would not be
      updated until ufs_inactive() cleared the inode of the newly removed
      directory, which might be deferred indefinitely.  ufs_inactive()
      will not be called as long as any process holds a reference to the
      removed directory, and ufs_inactive() will not clear the inode if
      the link count is non-zero, which could be the result of an earlier
      system crash.
  
      If a background fsck is run before the update of the parent directory's
      actual link count has been performed, or at least scheduled by
      putting the dirrem on the leaf directory's inodedep id_bufwait list,
      fsck will corrupt the file system by decrementing the parent
      directory's effective link count, which was previously correct
      because it already took the removal of the leaf directory into
      account, and setting the actual link count to the same value as the
      effective link count after the dangling, removed, leaf directory
      has been removed.  This happens because fsck acts based on the
      actual link count, which will be too high when fsck creates the
      file system snapshot that it references.
  
      This change has the fortunate side effect of more quickly cleaning
      up the large number dirrem structures that linger for an extended
      time after the removal of a large directory tree.  It also fixes a
      potential problem with the shutdown of the syncer thread timing out
      if the system is rebooted immediately after removing a large directory
      tree.
  
      Submitted by:   tegge
      MFC after:      3 days
  
      Revision  Changes    Path
      1.185     +2 -0      src/sys/ufs/ffs/ffs_softdep.c
  
  Submitted by:   tegge
  
  Revision   Changes    Path
  1.156.2.7  +2 -0      src/sys/ufs/ffs/ffs_softdep.c