[PATCH] r/o bind mounts: elevate write count for rmdir and unlink.

Elevate the write count during the vfs_rmdir() and vfs_unlink().

[AV: merged rmdir and unlink parts, added missing pieces in nfsd]

Acked-by: Serge Hallyn <serue@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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 1 deletions

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 60f7a27f7a9e..34262c11f480 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -742,8 +742,11 @@ asmlinkage long sys_mq_unlink(const char __user *u_name)
         inode = dentry->d_inode;
         if (inode)
                 atomic_inc(&inode->i_count);
-
+        err = mnt_want_write(mqueue_mnt);
+        if (err)
+                goto out_err;
         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
+        mnt_drop_write(mqueue_mnt);
 out_err:
         dput(dentry);