[PATCH] fuse: check directory aliasing in mkdir

Check the created directory inode for aliases in the mkdir() method.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 9 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index c045cc70c749..3a47247a889e 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -74,6 +74,19 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
         return 1;
 }
 
+static int dir_alias(struct inode *inode)
+{
+        if (S_ISDIR(inode->i_mode)) {
+                /* Don't allow creating an alias to a directory  */
+                struct dentry *alias = d_find_alias(inode);
+                if (alias) {
+                        dput(alias);
+                        return 1;
+                }
+        }
+        return 0;
+}
+
 static struct dentry_operations fuse_dentry_operations = {
         .d_revalidate   = fuse_dentry_revalidate,
 };
@@ -263,7 +276,7 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
         fuse_put_request(fc, req);
 
         /* Don't allow userspace to do really stupid things... */
-        if ((inode->i_mode ^ mode) & S_IFMT) {
+        if (((inode->i_mode ^ mode) & S_IFMT) || dir_alias(inode)) {
                 iput(inode);
                 return -EIO;
         }
@@ -874,14 +887,9 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
         err = fuse_lookup_iget(dir, entry, &inode);
         if (err)
                 return ERR_PTR(err);
-        if (inode && S_ISDIR(inode->i_mode)) {
-                /* Don't allow creating an alias to a directory  */
-                struct dentry *alias = d_find_alias(inode);
-                if (alias) {
-                        dput(alias);
-                        iput(inode);
-                        return ERR_PTR(-EIO);
-                }
+        if (inode && dir_alias(inode)) {
+                iput(inode);
+                return ERR_PTR(-EIO);
         }
         d_add(entry, inode);
         return NULL;