From 936ad9094462578953042d3395b973f1c9e6fa95 Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Wed, 2 May 2012 07:19:09 -0400 Subject: [PATCH] cifs - check S_AUTOMOUNT in revalidate When revalidating a dentry, if the inode wasn't known to be a dfs entry when the dentry was instantiated, such as when created via ->readdir(), the DCACHE_NEED_AUTOMOUNT flag needs to be set on the dentry in ->d_revalidate(). The false return from cifs_d_revalidate(), due to the inode now being marked with the S_AUTOMOUNT flag, might not invalidate the dentry if there is a concurrent unlazy path walk. This is because the dentry reference count will be at least 2 in this case causing d_invalidate() to return EBUSY. So the asumption that the dentry will be discarded then correctly instantiated via ->lookup() might not hold. Signed-off-by: Ian Kent Reviewed-by: Jeff Layton Cc: Steve French Cc: linux-cifs@vger.kernel.org Signed-off-by: Steve French --- fs/cifs/dir.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index d172c8ed9017..ec4e9a2a12f8 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -668,12 +668,19 @@ cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd) return 0; else { /* - * Forcibly invalidate automounting directory inodes - * (remote DFS directories) so to have them - * instantiated again for automount + * If the inode wasn't known to be a dfs entry when + * the dentry was instantiated, such as when created + * via ->readdir(), it needs to be set now since the + * attributes will have been updated by + * cifs_revalidate_dentry(). */ - if (IS_AUTOMOUNT(direntry->d_inode)) - return 0; + if (IS_AUTOMOUNT(direntry->d_inode) && + !(direntry->d_flags & DCACHE_NEED_AUTOMOUNT)) { + spin_lock(&direntry->d_lock); + direntry->d_flags |= DCACHE_NEED_AUTOMOUNT; + spin_unlock(&direntry->d_lock); + } + return 1; } }