[PATCH] r/o bind mounts: write counts for truncate()

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>

diff --git a/fs/open.c b/fs/open.c
index e2df8fd1eb0b329e51eb887f968da9404a5652db..4d690e33446f854f960645a1b57258e133dd5e11 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -244,21 +244,21 @@ static long do_sys_truncate(const char __user * path, loff_t length)
        if (!S_ISREG(inode->i_mode))
                goto dput_and_out;
 
-       error = vfs_permission(&nd, MAY_WRITE);
+       error = mnt_want_write(nd.path.mnt);
        if (error)
                goto dput_and_out;
 
-       error = -EROFS;
-       if (IS_RDONLY(inode))
-               goto dput_and_out;
+       error = vfs_permission(&nd, MAY_WRITE);
+       if (error)
+               goto mnt_drop_write_and_out;
 
        error = -EPERM;
        if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
-               goto dput_and_out;
+               goto mnt_drop_write_and_out;
 
        error = get_write_access(inode);
        if (error)
-               goto dput_and_out;
+               goto mnt_drop_write_and_out;
 
        /*
         * Make sure that there are no leases.  get_write_access() protects
@@ -276,6 +276,8 @@ static long do_sys_truncate(const char __user * path, loff_t length)
 
 put_write_and_out:
        put_write_access(inode);
+mnt_drop_write_and_out:
+       mnt_drop_write(nd.path.mnt);
 dput_and_out:
        path_put(&nd.path);
 out: