[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, 5 insertions, 5 deletions

diff --git a/arch/parisc/hpux/sys_hpux.c b/arch/parisc/hpux/sys_hpux.c
index 05273ccced0e..cb69727027ae 100644
--- a/arch/parisc/hpux/sys_hpux.c
+++ b/arch/parisc/hpux/sys_hpux.c
@@ -145,7 +145,7 @@ static int hpux_ustat(dev_t dev, struct hpux_ustat __user *ubuf)
         s = user_get_super(dev);
         if (s == NULL)
                 goto out;
-        err = vfs_statfs(s, &sbuf);
+        err = vfs_statfs(s->s_root, &sbuf);
         drop_super(s);
         if (err)
                 goto out;
@@ -186,12 +186,12 @@ struct hpux_statfs {
      int16_t f_pad;
 };
 
-static int vfs_statfs_hpux(struct super_block *sb, struct hpux_statfs *buf)
+static int vfs_statfs_hpux(struct dentry *dentry, struct hpux_statfs *buf)
 {
         struct kstatfs st;
         int retval;
         
-        retval = vfs_statfs(sb, &st);
+        retval = vfs_statfs(dentry, &st);
         if (retval)
                 return retval;
 
@@ -219,7 +219,7 @@ asmlinkage long hpux_statfs(const char __user *path,
         error = user_path_walk(path, &nd);
         if (!error) {
                 struct hpux_statfs tmp;
-                error = vfs_statfs_hpux(nd.dentry->d_inode->i_sb, &tmp);
+                error = vfs_statfs_hpux(nd.dentry, &tmp);
                 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
                         error = -EFAULT;
                 path_release(&nd);
@@ -237,7 +237,7 @@ asmlinkage long hpux_fstatfs(unsigned int fd, struct hpux_statfs __user * buf)
         file = fget(fd);
         if (!file)
                 goto out;
-        error = vfs_statfs_hpux(file->f_dentry->d_inode->i_sb, &tmp);
+        error = vfs_statfs_hpux(file->f_dentry, &tmp);
         if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
                 error = -EFAULT;
         fput(file);