namei: split off filename_lookupat() with LOOKUP_PARENT

new functions: filename_parentat() and path_parentat() resp.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index 51e2214..6f95bc9 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2034,7 +2034,7 @@ static int path_lookupat(int dfd, const struct filename *name,
         * be able to complete).
         */
        err = path_init(dfd, name, flags, nd);
-       if (!err && !(flags & LOOKUP_PARENT)) {
+       if (!err) {
                while ((err = lookup_last(nd)) > 0) {
                        err = trailing_symlink(nd);
                        if (err)
@@ -2074,6 +2074,35 @@ static int filename_lookup(int dfd, struct filename *name,
        return retval;
 }
 
+/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
+static int path_parentat(int dfd, const struct filename *name,
+                               unsigned int flags, struct nameidata *nd)
+{
+       int err = path_init(dfd, name, flags | LOOKUP_PARENT, nd);
+       if (!err)
+               err = complete_walk(nd);
+       path_cleanup(nd);
+       return err;
+}
+
+static int filename_parentat(int dfd, struct filename *name,
+                               unsigned int flags, struct nameidata *nd)
+{
+       int retval;
+       struct nameidata *saved_nd = set_nameidata(nd);
+
+       retval = path_parentat(dfd, name, flags | LOOKUP_RCU, nd);
+       if (unlikely(retval == -ECHILD))
+               retval = path_parentat(dfd, name, flags, nd);
+       if (unlikely(retval == -ESTALE))
+               retval = path_parentat(dfd, name, flags | LOOKUP_REVAL, nd);
+
+       if (likely(!retval))
+               audit_inode(name, nd->path.dentry, LOOKUP_PARENT);
+       restore_nameidata(saved_nd);
+       return retval;
+}
+
 /* does lookup, returns the object with parent locked */
 struct dentry *kern_path_locked(const char *name, struct path *path)
 {
@@ -2085,7 +2114,7 @@ struct dentry *kern_path_locked(const char *name, struct path *path)
        if (IS_ERR(filename))
                return ERR_CAST(filename);
 
-       err = filename_lookup(AT_FDCWD, filename, LOOKUP_PARENT, &nd);
+       err = filename_parentat(AT_FDCWD, filename, 0, &nd);
        if (err) {
                d = ERR_PTR(err);
                goto out;
@@ -2255,7 +2284,7 @@ user_path_parent(int dfd, const char __user *path,
        if (IS_ERR(s))
                return s;
 
-       error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, &nd);
+       error = filename_parentat(dfd, s, flags, &nd);
        if (error) {
                putname(s);
                return ERR_PTR(error);
@@ -3344,7 +3373,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
         */
        lookup_flags &= LOOKUP_REVAL;
 
-       error = filename_lookup(dfd, name, LOOKUP_PARENT|lookup_flags, &nd);
+       error = filename_parentat(dfd, name, lookup_flags, &nd);
        if (error)
                return ERR_PTR(error);