Autofs may set the DCACHE_NEED_AUTOMOUNT flag on negative dentries. These
need attention from the automounter daemon regardless of the LOOKUP_FOLLOW flag.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Acked-by: Ian Kent <raven@xxxxxxxxxx>
---
fs/namei.c | 27 +++++++++++++++++++--------
1 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 0223c41..93e221e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -777,18 +777,29 @@ static int follow_automount(struct path *path, unsigned flags,
if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_CONTINUE))
return -EISDIR; /* we actually want to stop here */
- /* We want to mount if someone is trying to open/create a file of any
- * type under the mountpoint, wants to traverse through the mountpoint
- * or wants to open the mounted directory.
- *
- * We don't want to mount if someone's just doing a stat and they've
+ /* We don't want to mount if someone's just doing a stat and they've
* set AT_SYMLINK_NOFOLLOW - unless they're stat'ing a directory and
* appended a '/' to the name.
*/
- if (!(flags & LOOKUP_FOLLOW) &&
- !(flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY |
- LOOKUP_OPEN | LOOKUP_CREATE)))
+ if (!(flags & LOOKUP_FOLLOW)) {
+ /* We do, however, want to mount if someone wants to open or
+ * create a file of any type under the mountpoint, wants to
+ * traverse through the mountpoint or wants to open the mounted
+ * directory.
+ */
+ if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY |
+ LOOKUP_OPEN | LOOKUP_CREATE))
+ goto need_automount;
+
+ /* Also, autofs may mark negative dentries as being automount
+ * points. These will need the attentions of the daemon to
+ * instantiate them before they can be used.
+ */
+ if (!path->dentry->d_inode)
+ goto need_automount;
return -EISDIR;
+ }
+need_automount:
current->total_link_count++;
if (current->total_link_count >= 40)
--
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