ocfs2: fix deadlock issue when taking inode lock at vfs entry points

Commit 743b5f1434f5 ("ocfs2: take inode lock in ocfs2_iop_set/get_acl()")
results in a deadlock, as the author "Tariq Saeed" realized shortly
after the patch was merged.  The discussion happened here

  https://oss.oracle.com/pipermail/ocfs2-devel/2015-September/011085.html

The reason why taking cluster inode lock at vfs entry points opens up a
self deadlock window, is explained in the previous patch of this series.

So far, we have seen two different code paths that have this issue.

1. do_sys_open
     may_open
      inode_permission
       ocfs2_permission
        ocfs2_inode_lock() <=== take PR
         generic_permission
          get_acl
           ocfs2_iop_get_acl
            ocfs2_inode_lock() <=== take PR

2. fchmod|fchmodat
    chmod_common
     notify_change
      ocfs2_setattr <=== take EX
       posix_acl_chmod
        get_acl
         ocfs2_iop_get_acl <=== take PR
        ocfs2_iop_set_acl <=== take EX

Fixes them by adding the tracking logic (in the previous patch) for these
funcs above, ocfs2_permission(), ocfs2_iop_[set|get]_acl(),
ocfs2_setattr().

Link: http://lkml.kernel.org/r/20170117100948.11657-3-zren@suse.com
Signed-off-by: Eric Ren <zren@suse.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions