1 files changed, 14 insertions, 0 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 3f73eb1f195a..71efc7000226 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -199,6 +199,17 @@ int init_file(struct file *file, struct vfsmount *mnt, struct dentry *dentry,
         file->f_mapping = dentry->d_inode->i_mapping;
         file->f_mode = mode;
         file->f_op = fop;
+
+        /*
+         * These mounts don't really matter in practice
+         * for r/o bind mounts.  They aren't userspace-
+         * visible.  We do this for consistency, and so
+         * that we can do debugging checks at __fput()
+         */
+        if ((mode & FMODE_WRITE) && !special_file(dentry->d_inode->i_mode)) {
+                error = mnt_want_write(mnt);
+                WARN_ON(error);
+        }
         return error;
 }
 EXPORT_SYMBOL(init_file);
@@ -221,10 +232,13 @@ EXPORT_SYMBOL(fput);
  */
 void drop_file_write_access(struct file *file)
 {
+        struct vfsmount *mnt = file->f_path.mnt;
         struct dentry *dentry = file->f_path.dentry;
         struct inode *inode = dentry->d_inode;
 
         put_write_access(inode);
+        if (!special_file(inode->i_mode))
+                mnt_drop_write(mnt);
 }
 EXPORT_SYMBOL_GPL(drop_file_write_access);