[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>

3 files changed, 6 insertions, 6 deletions

diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index 4a37c2bbfa3f..506ff87c1d4b 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -48,7 +48,7 @@
 
 static void smb_delete_inode(struct inode *);
 static void smb_put_super(struct super_block *);
-static int  smb_statfs(struct super_block *, struct kstatfs *);
+static int  smb_statfs(struct dentry *, struct kstatfs *);
 static int  smb_show_options(struct seq_file *, struct vfsmount *);
 
 static kmem_cache_t *smb_inode_cachep;
@@ -641,13 +641,13 @@ out_no_server:
 }
 
 static int
-smb_statfs(struct super_block *sb, struct kstatfs *buf)
+smb_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         int result;
         
         lock_kernel();
 
-        result = smb_proc_dskattr(sb, buf);
+        result = smb_proc_dskattr(dentry, buf);
 
         unlock_kernel();
 
diff --git a/fs/smbfs/proc.c b/fs/smbfs/proc.c
index b1b878b81730..c3495059889d 100644
--- a/fs/smbfs/proc.c
+++ b/fs/smbfs/proc.c
@@ -3226,9 +3226,9 @@ smb_proc_settime(struct dentry *dentry, struct smb_fattr *fattr)
 }
 
 int
-smb_proc_dskattr(struct super_block *sb, struct kstatfs *attr)
+smb_proc_dskattr(struct dentry *dentry, struct kstatfs *attr)
 {
-        struct smb_sb_info *server = SMB_SB(sb);
+        struct smb_sb_info *server = SMB_SB(dentry->d_sb);
         int result;
         char *p;
         long unit;
diff --git a/fs/smbfs/proto.h b/fs/smbfs/proto.h
index 47664597e6b1..972ed7dad388 100644
--- a/fs/smbfs/proto.h
+++ b/fs/smbfs/proto.h
@@ -29,7 +29,7 @@ extern int smb_proc_getattr(struct dentry *dir, struct smb_fattr *fattr);
 extern int smb_proc_setattr(struct dentry *dir, struct smb_fattr *fattr);
 extern int smb_proc_setattr_unix(struct dentry *d, struct iattr *attr, unsigned int major, unsigned int minor);
 extern int smb_proc_settime(struct dentry *dentry, struct smb_fattr *fattr);
-extern int smb_proc_dskattr(struct super_block *sb, struct kstatfs *attr);
+extern int smb_proc_dskattr(struct dentry *dentry, struct kstatfs *attr);
 extern int smb_proc_read_link(struct smb_sb_info *server, struct dentry *d, char *buffer, int len);
 extern int smb_proc_symlink(struct smb_sb_info *server, struct dentry *d, const char *oldpath);
 extern int smb_proc_link(struct smb_sb_info *server, struct dentry *dentry, struct dentry *new_dentry);