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authorLinus Torvalds <torvalds@linux-foundation.org>2011-09-26 17:44:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-09-26 17:44:55 -0700
commitd94c177beeb4469cd4f6e83354ab0223353e98ed (patch)
tree0ce1b8a3d9d35afd3df533ce58eb8d1f2f401f81
parent858b1814b89d043a3866299c258ccdc27eb2538c (diff)
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>
-rw-r--r--fs/namei.c2
-rw-r--r--include/linux/namei.h1
2 files changed, 2 insertions, 1 deletions
diff --git a/fs/namei.c b/fs/namei.c
index f4788365ea22..09606fd83d57 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -739,7 +739,7 @@ static int follow_automount(struct path *path, unsigned flags,
* of the daemon to instantiate them before they can be used.
*/
if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
- LOOKUP_OPEN | LOOKUP_CREATE)) &&
+ LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
path->dentry->d_inode)
return -EISDIR;
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 76fe2c62ae71..e13dac7caab2 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -48,6 +48,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
*/
#define LOOKUP_FOLLOW 0x0001
#define LOOKUP_DIRECTORY 0x0002
+#define LOOKUP_AUTOMOUNT 0x0004
#define LOOKUP_PARENT 0x0010
#define LOOKUP_REVAL 0x0020