namei: pass the struct path to store the result down into path_lookupat()

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

1 files changed, 34 insertions, 38 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 177934c79a04..f4c9c0774b26 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2086,8 +2086,8 @@ static inline int lookup_last(struct nameidata *nd)
 }
 
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int path_lookupat(int dfd, const struct filename *name,
-                                unsigned int flags, struct nameidata *nd)
+static int path_lookupat(int dfd, const struct filename *name, unsigned flags,
+                         struct nameidata *nd, struct path *path)
 {
         const char *s = path_init(dfd, name, flags, nd);
         int err;
@@ -2108,27 +2108,31 @@ static int path_lookupat(int dfd, const struct filename *name,
         if (!err && nd->flags & LOOKUP_DIRECTORY)
                 if (!d_can_lookup(nd->path.dentry))
                         err = -ENOTDIR;
-        if (err)
-                terminate_walk(nd);
-
+        if (!err) {
+                *path = nd->path;
+                nd->path.mnt = NULL;
+                nd->path.dentry = NULL;
+        }
+        terminate_walk(nd);
         path_cleanup(nd);
         return err;
 }
 
-static int filename_lookup(int dfd, struct filename *name,
-                                unsigned int flags, struct nameidata *nd)
+static int filename_lookup(int dfd, struct filename *name, unsigned flags,
+                           struct nameidata *nd, struct path *path)
 {
         int retval;
         struct nameidata *saved_nd = set_nameidata(nd);
 
-        retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd);
+        retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd, path);
         if (unlikely(retval == -ECHILD))
-                retval = path_lookupat(dfd, name, flags, nd);
+                retval = path_lookupat(dfd, name, flags, nd, path);
         if (unlikely(retval == -ESTALE))
-                retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd);
+                retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL,
+                                       nd, path); 
 
         if (likely(!retval))
-                audit_inode(name, nd->path.dentry, flags & LOOKUP_PARENT);
+                audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
         restore_nameidata(saved_nd);
         return retval;
 }
@@ -2209,10 +2213,8 @@ int kern_path(const char *name, unsigned int flags, struct path *path)
         int res = PTR_ERR(filename);
 
         if (!IS_ERR(filename)) {
-                res = filename_lookup(AT_FDCWD, filename, flags, &nd);
+                res = filename_lookup(AT_FDCWD, filename, flags, &nd, path);
                 putname(filename);
-                if (!res)
-                        *path = nd.path;
         }
         return res;
 }
@@ -2241,9 +2243,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
                 nd.root.dentry = dentry;
                 nd.root.mnt = mnt;
                 err = filename_lookup(AT_FDCWD, filename,
-                                      flags | LOOKUP_ROOT, &nd);
-                if (!err)
-                        *path = nd.path;
+                                      flags | LOOKUP_ROOT, &nd, path);
                 putname(filename);
         }
         return err;
@@ -2311,10 +2311,8 @@ int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
 
                 BUG_ON(flags & LOOKUP_PARENT);
 
-                err = filename_lookup(dfd, tmp, flags, &nd);
+                err = filename_lookup(dfd, tmp, flags, &nd, path);
                 putname(tmp);
-                if (!err)
-                        *path = nd.path;
         }
         return err;
 }
@@ -3261,44 +3259,42 @@ static int do_tmpfile(int dfd, struct filename *pathname,
                 struct file *file, int *opened)
 {
         static const struct qstr name = QSTR_INIT("/", 1);
-        struct dentry *dentry, *child;
+        struct dentry *child;
         struct inode *dir;
+        struct path path;
         int error = path_lookupat(dfd, pathname,
-                                  flags | LOOKUP_DIRECTORY, nd);
+                                  flags | LOOKUP_DIRECTORY, nd, &path);
         if (unlikely(error))
                 return error;
-        error = mnt_want_write(nd->path.mnt);
+        error = mnt_want_write(path.mnt);
         if (unlikely(error))
                 goto out;
+        dir = path.dentry->d_inode;
         /* we want directory to be writable */
-        error = inode_permission(nd->inode, MAY_WRITE | MAY_EXEC);
+        error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
         if (error)
                 goto out2;
-        dentry = nd->path.dentry;
-        dir = dentry->d_inode;
         if (!dir->i_op->tmpfile) {
                 error = -EOPNOTSUPP;
                 goto out2;
         }
-        child = d_alloc(dentry, &name);
+        child = d_alloc(path.dentry, &name);
         if (unlikely(!child)) {
                 error = -ENOMEM;
                 goto out2;
         }
-        nd->flags &= ~LOOKUP_DIRECTORY;
-        nd->flags |= op->intent;
-        dput(nd->path.dentry);
-        nd->path.dentry = child;
-        error = dir->i_op->tmpfile(dir, nd->path.dentry, op->mode);
+        dput(path.dentry);
+        path.dentry = child;
+        error = dir->i_op->tmpfile(dir, child, op->mode);
         if (error)
                 goto out2;
-        audit_inode(pathname, nd->path.dentry, 0);
+        audit_inode(pathname, child, 0);
         /* Don't check for other permissions, the inode was just created */
-        error = may_open(&nd->path, MAY_OPEN, op->open_flag);
+        error = may_open(&path, MAY_OPEN, op->open_flag);
         if (error)
                 goto out2;
-        file->f_path.mnt = nd->path.mnt;
-        error = finish_open(file, nd->path.dentry, NULL, opened);
+        file->f_path.mnt = path.mnt;
+        error = finish_open(file, child, NULL, opened);
         if (error)
                 goto out2;
         error = open_check_o_direct(file);
@@ -3311,9 +3307,9 @@ static int do_tmpfile(int dfd, struct filename *pathname,
                 spin_unlock(&inode->i_lock);
         }
 out2:
-        mnt_drop_write(nd->path.mnt);
+        mnt_drop_write(path.mnt);
 out:
-        path_put(&nd->path);
+        path_put(&path);
         return error;
 }