[PATCH 23/30] r/o bind mounts: write counts for truncate()

[Dave Hansen <haveblue@us.ibm.com>]

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>
---

 linux-2.6.git-dave/fs/open.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff -puN fs/open.c~r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate fs/open.c
--- linux-2.6.git/fs/open.c~r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate	2008-02-15 13:25:55.000000000 -0800
+++ linux-2.6.git-dave/fs/open.c	2008-02-15 13:25:55.000000000 -0800
@@ -244,21 +244,21 @@ static long do_sys_truncate(const char _
 	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 _
 
 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:
_