vfs: do_last(): separate O_CREAT specific code

Check O_CREAT on the slow lookup paths where necessary.  This allows the rest to
be shared with plain open.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 17 insertions, 16 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 68742e3cb98d..12ed29712b4e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2274,22 +2274,23 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
                         inode = path->dentry->d_inode;
                 }
                 goto finish_lookup;
-        }
-
-        /* create side of things */
-        /*
-         * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED has been
-         * cleared when we got to the last component we are about to look up
-         */
-        error = complete_walk(nd);
-        if (error)
-                return ERR_PTR(error);
+        } else {
+                /* create side of things */
+                /*
+                 * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED
+                 * has been cleared when we got to the last component we are
+                 * about to look up
+                 */
+                error = complete_walk(nd);
+                if (error)
+                        return ERR_PTR(error);
 
-        audit_inode(pathname, dir);
-        error = -EISDIR;
-        /* trailing slashes? */
-        if (nd->last.name[nd->last.len])
-                goto exit;
+                audit_inode(pathname, dir);
+                error = -EISDIR;
+                /* trailing slashes? */
+                if (nd->last.name[nd->last.len])
+                        goto exit;
+        }
 
 retry_lookup:
         mutex_lock(&dir->d_inode->i_mutex);
@@ -2305,7 +2306,7 @@ retry_lookup:
         path->mnt = nd->path.mnt;
 
         /* Negative dentry, just create the file */
-        if (!dentry->d_inode) {
+        if (!dentry->d_inode && (open_flag & O_CREAT)) {
                 umode_t mode = op->mode;
                 if (!IS_POSIXACL(dir->d_inode))
                         mode &= ~current_umask();