| Date | Wed, 09 Nov 2011 13:27:31 -0800 | From | Greg KH <> | Subject | [129/262] VFS: Fix automount for negative autofs dentries |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: David Howells <dhowells@redhat.com>
commit 5a30d8a2b8ddd5102c440c7e5a7c8e1fd729c818 upstream. [ backport for 3.0.x: LOOKUP_PARENT => LOOKUP_CONTINUE by Chuck Ebbert <cebbert@redhat.com> ]
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@redhat.com> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Chuck Ebbert <cebbert@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/namei.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-)
--- a/fs/namei.c +++ b/fs/namei.c @@ -781,19 +781,25 @@ static int follow_automount(struct path 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 * 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))) - return -EISDIR; - + 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. + * 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 (!(flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY | + LOOKUP_OPEN | LOOKUP_CREATE)) && + path->dentry->d_inode) + return -EISDIR; + } current->total_link_count++; if (current->total_link_count >= 40) return -ELOOP;
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