mark struct file that had write access grabbed by open()

new flag in ->f_mode - FMODE_WRITER.  Set by do_dentry_open() in case
when it has grabbed write access, checked by __fput() to decide whether
it wants to drop the sucker.  Allows to stop bothering with mnt_clone_write()
in alloc_file(), along with fewer special_file() checks.

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

1 files changed, 1 insertions, 3 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index a66aff5bd3fe..20e8696c31a7 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -414,9 +414,7 @@ EXPORT_SYMBOL_GPL(mnt_clone_write);
  */
 int __mnt_want_write_file(struct file *file)
 {
-        struct inode *inode = file_inode(file);
-
-        if (!(file->f_mode & FMODE_WRITE) || special_file(inode->i_mode))
+        if (!(file->f_mode & FMODE_WRITER))
                 return __mnt_want_write(file->f_path.mnt);
         else
                 return mnt_clone_write(file->f_path.mnt);