[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>

2 files changed, 2 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index de3998f15f10..5446a0861d1d 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1310,7 +1310,7 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         if ((bmval0 & (FATTR4_WORD0_FILES_FREE | FATTR4_WORD0_FILES_TOTAL)) ||
             (bmval1 & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
                        FATTR4_WORD1_SPACE_TOTAL))) {
-                status = vfs_statfs(dentry->d_inode->i_sb, &statfs);
+                status = vfs_statfs(dentry, &statfs);
                 if (status)
                         goto out_nfserr;
         }
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 1d65f13f458c..245eaa1fb59b 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1737,7 +1737,7 @@ int
 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat)
 {
         int err = fh_verify(rqstp, fhp, 0, MAY_NOP);
-        if (!err && vfs_statfs(fhp->fh_dentry->d_inode->i_sb,stat))
+        if (!err && vfs_statfs(fhp->fh_dentry,stat))
                 err = nfserr_io;
         return err;
 }