new helpers: file_removexattr(), filename_removexattr()

switch path_removexattrat() and fremovexattr(2) to those

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/xattr.c b/fs/xattr.c
index 988ea737ae7e9b0e45204b24c4b2d3229d5c5c79..b76911b23293fabbe99a6c67abb05c9c4ae06ce0 100644 (file)
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -957,23 +957,33 @@ removexattr(struct mnt_idmap *idmap, struct dentry *d, const char *name)
        return vfs_removexattr(idmap, d, name);
 }
 
-static int path_removexattr(const char __user *pathname,
-                           const char __user *name, unsigned int lookup_flags)
+static int file_removexattr(struct file *f, struct xattr_name *kname)
+{
+       int error = mnt_want_write_file(f);
+
+       if (!error) {
+               audit_file(f);
+               error = removexattr(file_mnt_idmap(f),
+                                   f->f_path.dentry, kname->name);
+               mnt_drop_write_file(f);
+       }
+       return error;
+}
+
+/* unconditionally consumes filename */
+static int filename_removexattr(int dfd, struct filename *filename,
+                               unsigned int lookup_flags, struct xattr_name *kname)
 {
        struct path path;
        int error;
-       struct xattr_name kname;
 
-       error = import_xattr_name(&kname, name);
-       if (error)
-               return error;
 retry:
-       error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
+       error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
        if (error)
-               return error;
+               goto out;
        error = mnt_want_write(path.mnt);
        if (!error) {
-               error = removexattr(mnt_idmap(path.mnt), path.dentry, kname.name);
+               error = removexattr(mnt_idmap(path.mnt), path.dentry, kname->name);
                mnt_drop_write(path.mnt);
        }
        path_put(&path);
@@ -981,9 +991,24 @@ retry:
                lookup_flags |= LOOKUP_REVAL;
                goto retry;
        }
+out:
+       putname(filename);
        return error;
 }
 
+static int path_removexattr(const char __user *pathname,
+                           const char __user *name, unsigned int lookup_flags)
+{
+       struct xattr_name kname;
+       int error;
+
+       error = import_xattr_name(&kname, name);
+       if (error)
+               return error;
+       return filename_removexattr(AT_FDCWD, getname(pathname), lookup_flags,
+                                   &kname);
+}
+
 SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
                const char __user *, name)
 {
@@ -1004,19 +1029,11 @@ SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
 
        if (fd_empty(f))
                return -EBADF;
-       audit_file(fd_file(f));
 
        error = import_xattr_name(&kname, name);
        if (error)
                return error;
-
-       error = mnt_want_write_file(fd_file(f));
-       if (!error) {
-               error = removexattr(file_mnt_idmap(fd_file(f)),
-                                   fd_file(f)->f_path.dentry, kname.name);
-               mnt_drop_write_file(fd_file(f));
-       }
-       return error;
+       return file_removexattr(fd_file(f), &kname);
 }
 
 int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name)