[PATCH] r/o bind mounts: write count for file_update_time()

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 6f6250c08ce6..27ee1af50d02 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1250,10 +1250,13 @@ void file_update_time(struct file *file)
         struct inode *inode = file->f_path.dentry->d_inode;
         struct timespec now;
         int sync_it = 0;
+        int err;
 
         if (IS_NOCMTIME(inode))
                 return;
-        if (IS_RDONLY(inode))
+
+        err = mnt_want_write(file->f_path.mnt);
+        if (err)
                 return;
 
         now = current_fs_time(inode->i_sb);
@@ -1274,6 +1277,7 @@ void file_update_time(struct file *file)
 
         if (sync_it)
                 mark_inode_dirty_sync(inode);
+        mnt_drop_write(file->f_path.mnt);
 }
 
 EXPORT_SYMBOL(file_update_time);