[PATCH] VFS: Permit filesystem to perform statfs with a known root dentry

Give the statfs superblock operation a dentry pointer rather than a superblock
pointer.

This complements the get_sb() patch.  That reduced the significance of
sb->s_root, allowing NFS to place a fake root there.  However, NFS does
require a dentry to use as a target for the statfs operation.  This permits
the root in the vfsmount to be used instead.

linux/mount.h has been added where necessary to make allyesconfig build
successfully.

Interest has also been expressed for use with the FUSE and XFS filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 524915dfda64..093efba4d9b6 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1903,13 +1903,13 @@ static int selinux_sb_kern_mount(struct super_block *sb, void *data)
         return superblock_has_perm(current, sb, FILESYSTEM__MOUNT, &ad);
 }
 
-static int selinux_sb_statfs(struct super_block *sb)
+static int selinux_sb_statfs(struct dentry *dentry)
 {
         struct avc_audit_data ad;
 
         AVC_AUDIT_DATA_INIT(&ad,FS);
-        ad.u.fs.dentry = sb->s_root;
-        return superblock_has_perm(current, sb, FILESYSTEM__GETATTR, &ad);
+        ad.u.fs.dentry = dentry->d_sb->s_root;
+        return superblock_has_perm(current, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
 }
 
 static int selinux_mount(char * dev_name,