• Ian Kent's avatar
    autofs: fix lockref lookup · 6b6751f7
    Ian Kent authored
    
    
    autofs needs to be able to see private data dentry flags for its dentrys
    that are being created but not yet hashed and for its dentrys that have
    been rmdir()ed but not yet freed.  It needs to do this so it can block
    processes in these states until a status has been returned to indicate
    the given operation is complete.
    
    It does this by keeping two lists, active and expring, of dentrys in
    this state and uses ->d_release() to keep them stable while it checks
    the reference count to determine if they should be used.
    
    But with the recent lockref changes dentrys being freed sometimes don't
    transition to a reference count of 0 before being freed so autofs can
    occassionally use a dentry that is invalid which can lead to a panic.
    Signed-off-by: default avatarIan Kent <raven@themaw.net>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    6b6751f7
root.c 23.2 KB