From: Al Viro Date: Fri, 18 Mar 2011 12:55:38 +0000 (-0400) Subject: change the locking order for namespace_sem X-Git-Tag: v2.6.39-rc1~419^2~3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b12cea9198fa99ffd3de1776c323bc7464d26b44;p=pandora-kernel.git change the locking order for namespace_sem Have it nested inside ->i_mutex. Instead of using follow_down() under namespace_sem, followed by grabbing i_mutex and checking that mountpoint to be is not dead, do the following: grab i_mutex check that it's not dead grab namespace_sem see if anything is mounted there if not, we've won otherwise drop locks put_path on what we had replace with what's mounted retry everything with new mountpoint to be New helper (lock_mount()) does that. do_add_mount(), do_move_mount(), do_loopback() and pivot_root() switched to it; in case of the last two that eliminates a race we used to have - original code didn't do follow_down(). Signed-off-by: Al Viro --- Reading git-diff-tree failed