[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>
diff --git a/include/linux/coda_psdev.h b/include/linux/coda_psdev.h
index d539262..98f6c52 100644
--- a/include/linux/coda_psdev.h
+++ b/include/linux/coda_psdev.h
@@ -70,7 +70,7 @@
unsigned int cmd, struct PioctlData *data);
int coda_downcall(int opcode, union outputArgs *out, struct super_block *sb);
int venus_fsync(struct super_block *sb, struct CodaFid *fid);
-int venus_statfs(struct super_block *sb, struct kstatfs *sfs);
+int venus_statfs(struct dentry *dentry, struct kstatfs *sfs);
/* messages between coda filesystem in kernel and Venus */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3e50dd2..c823a38 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1096,7 +1096,7 @@
int (*sync_fs)(struct super_block *sb, int wait);
void (*write_super_lockfs) (struct super_block *);
void (*unlockfs) (struct super_block *);
- int (*statfs) (struct super_block *, struct kstatfs *);
+ int (*statfs) (struct dentry *, struct kstatfs *);
int (*remount_fs) (struct super_block *, int *, char *);
void (*clear_inode) (struct inode *);
void (*umount_begin) (struct super_block *);
@@ -1325,7 +1325,7 @@
extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
struct vfsmount *);
-extern int vfs_statfs(struct super_block *, struct kstatfs *);
+extern int vfs_statfs(struct dentry *, struct kstatfs *);
/* /sys/fs */
extern struct subsystem fs_subsys;
@@ -1746,7 +1746,7 @@
extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
extern int dcache_readdir(struct file *, void *, filldir_t);
extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
-extern int simple_statfs(struct super_block *, struct kstatfs *);
+extern int simple_statfs(struct dentry *, struct kstatfs *);
extern int simple_link(struct dentry *, struct inode *, struct dentry *);
extern int simple_unlink(struct inode *, struct dentry *);
extern int simple_rmdir(struct inode *, struct dentry *);
diff --git a/include/linux/mount.h b/include/linux/mount.h
index b7472ae..60718f1 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -17,6 +17,11 @@
#include <linux/spinlock.h>
#include <asm/atomic.h>
+struct super_block;
+struct vfsmount;
+struct dentry;
+struct namespace;
+
#define MNT_NOSUID 0x01
#define MNT_NODEV 0x02
#define MNT_NOEXEC 0x04
diff --git a/include/linux/security.h b/include/linux/security.h
index 47722d3..383c320 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -171,9 +171,9 @@
* Deallocate and clear the sb->s_security field.
* @sb contains the super_block structure to be modified.
* @sb_statfs:
- * Check permission before obtaining filesystem statistics for the @sb
- * filesystem.
- * @sb contains the super_block structure for the filesystem.
+ * Check permission before obtaining filesystem statistics for the @mnt
+ * mountpoint.
+ * @dentry is a handle on the superblock for the filesystem.
* Return 0 if permission is granted.
* @sb_mount:
* Check permission before an object specified by @dev_name is mounted on
@@ -1127,7 +1127,7 @@
int (*sb_copy_data)(struct file_system_type *type,
void *orig, void *copy);
int (*sb_kern_mount) (struct super_block *sb, void *data);
- int (*sb_statfs) (struct super_block * sb);
+ int (*sb_statfs) (struct dentry *dentry);
int (*sb_mount) (char *dev_name, struct nameidata * nd,
char *type, unsigned long flags, void *data);
int (*sb_check_sb) (struct vfsmount * mnt, struct nameidata * nd);
@@ -1450,9 +1450,9 @@
return security_ops->sb_kern_mount (sb, data);
}
-static inline int security_sb_statfs (struct super_block *sb)
+static inline int security_sb_statfs (struct dentry *dentry)
{
- return security_ops->sb_statfs (sb);
+ return security_ops->sb_statfs (dentry);
}
static inline int security_sb_mount (char *dev_name, struct nameidata *nd,
@@ -2162,7 +2162,7 @@
return 0;
}
-static inline int security_sb_statfs (struct super_block *sb)
+static inline int security_sb_statfs (struct dentry *dentry)
{
return 0;
}