vfs pathname lookup: Add LOOKUP_AUTOMOUNT flag
authorLinus Torvalds <torvalds@linux-foundation.org>
Tue, 27 Sep 2011 00:44:55 +0000 (17:44 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 27 Sep 2011 00:44:55 +0000 (17:44 -0700)
commitd94c177beeb4469cd4f6e83354ab0223353e98ed
tree0ce1b8a3d9d35afd3df533ce58eb8d1f2f401f81
parent858b1814b89d043a3866299c258ccdc27eb2538c
vfs pathname lookup: Add LOOKUP_AUTOMOUNT flag

Since we've now turned around and made LOOKUP_FOLLOW *not* force an
automount, we want to add the ability to force an automount event on
lookup even if we don't happen to have one of the other flags that force
it implicitly (LOOKUP_OPEN, LOOKUP_DIRECTORY, LOOKUP_PARENT..)

Most cases will never want to use this, since you'd normally want to
delay automounting as long as possible, which usually implies
LOOKUP_OPEN (when we open a file or directory, we really cannot avoid
the automount any more).

But Trond argued sufficiently forcefully that at a minimum bind mounting
a file and quotactl will want to force the automount lookup.  Some other
cases (like nfs_follow_remote_path()) could use it too, although
LOOKUP_DIRECTORY would work there as well.

This commit just adds the flag and logic, no users yet, though.  It also
doesn't actually touch the LOOKUP_NO_AUTOMOUNT flag that is related, and
was made irrelevant by the same change that made us not follow on
LOOKUP_FOLLOW.

Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/namei.c
include/linux/namei.h