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

[Don Lewis]

On 29 Sep, Don Lewis wrote:
> 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

This may fix the "panic: handle_written_inodeblock: live inodedep"
problem.