[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, 5 insertions, 5 deletions

diff --git a/fs/coda/inode.c b/fs/coda/inode.c
index cba70201567d..87f1dc8aa24b 100644
--- a/fs/coda/inode.c
+++ b/fs/coda/inode.c
@@ -36,7 +36,7 @@
 /* VFS super_block ops */
 static void coda_clear_inode(struct inode *);
 static void coda_put_super(struct super_block *);
-static int coda_statfs(struct super_block *sb, struct kstatfs *buf);
+static int coda_statfs(struct dentry *dentry, struct kstatfs *buf);
 
 static kmem_cache_t * coda_inode_cachep;
 
@@ -278,13 +278,13 @@ struct inode_operations coda_file_inode_operations = {
         .setattr        = coda_setattr,
 };
 
-static int coda_statfs(struct super_block *sb, struct kstatfs *buf)
+static int coda_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         int error;
         
         lock_kernel();
 
-        error = venus_statfs(sb, buf);
+        error = venus_statfs(dentry, buf);
 
         unlock_kernel();
 
diff --git a/fs/coda/upcall.c b/fs/coda/upcall.c
index 1bae99650a91..b040eba13a7d 100644
--- a/fs/coda/upcall.c
+++ b/fs/coda/upcall.c
@@ -611,7 +611,7 @@ int venus_pioctl(struct super_block *sb, struct CodaFid *fid,
         return error;
 }
 
-int venus_statfs(struct super_block *sb, struct kstatfs *sfs) 
+int venus_statfs(struct dentry *dentry, struct kstatfs *sfs)
 { 
         union inputArgs *inp;
         union outputArgs *outp;
@@ -620,7 +620,7 @@ int venus_statfs(struct super_block *sb, struct kstatfs *sfs)
         insize = max_t(unsigned int, INSIZE(statfs), OUTSIZE(statfs));
         UPARG(CODA_STATFS);
 
-        error = coda_upcall(coda_sbp(sb), insize, &outsize, inp);
+        error = coda_upcall(coda_sbp(dentry->d_sb), insize, &outsize, inp);
         
         if (!error) {
                 sfs->f_blocks = outp->coda_statfs.stat.f_blocks;