[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>

4 files changed, 14 insertions, 14 deletions

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 31afe3d91ac6..e15dcf4f3dcd 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -244,7 +244,7 @@ do_osf_statfs(struct dentry * dentry, struct osf_statfs __user *buffer,
 	      unsigned long bufsiz)
 {
 	struct kstatfs linux_stat;
-	int error = vfs_statfs(dentry->d_inode->i_sb, &linux_stat);
+	int error = vfs_statfs(dentry, &linux_stat);
 	if (!error)
 		error = linux_to_osf_statfs(&linux_stat, buffer, bufsiz);
 	return error;	
diff --git a/arch/mips/kernel/sysirix.c b/arch/mips/kernel/sysirix.c
index 5407b784cd01..19e1ef43eb4b 100644
--- a/arch/mips/kernel/sysirix.c
+++ b/arch/mips/kernel/sysirix.c
@@ -694,7 +694,7 @@ asmlinkage int irix_statfs(const char __user *path,
 	if (error)
 		goto out;
 
-	error = vfs_statfs(nd.dentry->d_inode->i_sb, &kbuf);
+	error = vfs_statfs(nd.dentry, &kbuf);
 	if (error)
 		goto dput_and_out;
 
@@ -732,7 +732,7 @@ asmlinkage int irix_fstatfs(unsigned int fd, struct irix_statfs __user *buf)
 		goto out;
 	}
 
-	error = vfs_statfs(file->f_dentry->d_inode->i_sb, &kbuf);
+	error = vfs_statfs(file->f_dentry, &kbuf);
 	if (error)
 		goto out_f;
 
@@ -1360,7 +1360,7 @@ asmlinkage int irix_statvfs(char __user *fname, struct irix_statvfs __user *buf)
 	error = user_path_walk(fname, &nd);
 	if (error)
 		goto out;
-	error = vfs_statfs(nd.dentry->d_inode->i_sb, &kbuf);
+	error = vfs_statfs(nd.dentry, &kbuf);
 	if (error)
 		goto dput_and_out;
 
@@ -1406,7 +1406,7 @@ asmlinkage int irix_fstatvfs(int fd, struct irix_statvfs __user *buf)
 		error = -EBADF;
 		goto out;
 	}
-	error = vfs_statfs(file->f_dentry->d_inode->i_sb, &kbuf);
+	error = vfs_statfs(file->f_dentry, &kbuf);
 	if (error)
 		goto out_f;
 
@@ -1611,7 +1611,7 @@ asmlinkage int irix_statvfs64(char __user *fname, struct irix_statvfs64 __user *
 	error = user_path_walk(fname, &nd);
 	if (error)
 		goto out;
-	error = vfs_statfs(nd.dentry->d_inode->i_sb, &kbuf);
+	error = vfs_statfs(nd.dentry, &kbuf);
 	if (error)
 		goto dput_and_out;
 
@@ -1658,7 +1658,7 @@ asmlinkage int irix_fstatvfs64(int fd, struct irix_statvfs __user *buf)
 		error = -EBADF;
 		goto out;
 	}
-	error = vfs_statfs(file->f_dentry->d_inode->i_sb, &kbuf);
+	error = vfs_statfs(file->f_dentry, &kbuf);
 	if (error)
 		goto out_f;
 
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);
diff --git a/arch/sparc64/solaris/fs.c b/arch/sparc64/solaris/fs.c
index 4885ca6cbc77..0f0eb6aa1c40 100644
--- a/arch/sparc64/solaris/fs.c
+++ b/arch/sparc64/solaris/fs.c
@@ -356,7 +356,7 @@ static int report_statvfs(struct vfsmount *mnt, struct inode *inode, u32 buf)
 	int error;
 	struct sol_statvfs __user *ss = A(buf);
 
-	error = vfs_statfs(mnt->mnt_sb, &s);
+	error = vfs_statfs(mnt->mnt_root, &s);
 	if (!error) {
 		const char *p = mnt->mnt_sb->s_type->name;
 		int i = 0;
@@ -392,7 +392,7 @@ static int report_statvfs64(struct vfsmount *mnt, struct inode *inode, u32 buf)
 	int error;
 	struct sol_statvfs64 __user *ss = A(buf);
 			
-	error = vfs_statfs(mnt->mnt_sb, &s);
+	error = vfs_statfs(mnt->mnt_root, &s);
 	if (!error) {
 		const char *p = mnt->mnt_sb->s_type->name;
 		int i = 0;