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authorIan Kent <raven@themaw.net>2012-05-02 07:19:09 -0400
committerSteve French <sfrench@us.ibm.com>2012-05-03 13:49:47 -0500
commit936ad9094462578953042d3395b973f1c9e6fa95 (patch)
tree22d52c9a2489768a9d70d95ef1a99c78185698c3 /fs
parent58fa015f611b51e1f501b048bc5ac263c78852f0 (diff)
downloadlinux-linaro-stable-936ad9094462578953042d3395b973f1c9e6fa95.tar.gz
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 <raven@themaw.net> Reviewed-by: Jeff Layton <jlayton@redhat.com> Cc: Steve French <smfrench@gmail.com> Cc: linux-cifs@vger.kernel.org Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/dir.c17
1 files 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;
}
}