vfs: new helper - vfs_ustat()

... and bury user_get_super()/statfs_by_dentry() - they are
purely internal now.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 15 insertions, 16 deletions

diff --git a/fs/compat.c b/fs/compat.c
index c98787536bb8..9db5a6076610 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -342,16 +342,9 @@ asmlinkage long compat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct c
  */
 asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u)
 {
-        struct super_block *sb;
         struct compat_ustat tmp;
         struct kstatfs sbuf;
-        int err;
-
-        sb = user_get_super(new_decode_dev(dev));
-        if (!sb)
-                return -EINVAL;
-        err = statfs_by_dentry(sb->s_root, &sbuf);
-        drop_super(sb);
+        int err = vfs_ustat(new_decode_dev(dev), &sbuf);
         if (err)
                 return err;
 
diff --git a/fs/internal.h b/fs/internal.h
index 839d3f9e9173..7b1cb1528ac2 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -78,6 +78,7 @@ extern int do_remount_sb(struct super_block *, int, void *, int);
 extern bool grab_super_passive(struct super_block *sb);
 extern struct dentry *mount_fs(struct file_system_type *,
                                int, const char *, void *);
+extern struct super_block *user_get_super(dev_t);
 
 /*
  * open.c
diff --git a/fs/statfs.c b/fs/statfs.c
index 9cf04a118965..2aa6a22e0be2 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -7,6 +7,7 @@
 #include <linux/statfs.h>
 #include <linux/security.h>
 #include <linux/uaccess.h>
+#include "internal.h"
 
 static int flags_by_mnt(int mnt_flags)
 {
@@ -45,7 +46,7 @@ static int calculate_f_flags(struct vfsmount *mnt)
                 flags_by_sb(mnt->mnt_sb->s_flags);
 }
 
-int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
+static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
 {
         int retval;
 
@@ -205,19 +206,23 @@ SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user
         return error;
 }
 
-SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
+int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
 {
-        struct super_block *s;
-        struct ustat tmp;
-        struct kstatfs sbuf;
+        struct super_block *s = user_get_super(dev);
         int err;
-
-        s = user_get_super(new_decode_dev(dev));
         if (!s)
                 return -EINVAL;
 
-        err = statfs_by_dentry(s->s_root, &sbuf);
+        err = statfs_by_dentry(s->s_root, sbuf);
         drop_super(s);
+        return err;
+}
+
+SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
+{
+        struct ustat tmp;
+        struct kstatfs sbuf;
+        int err = vfs_ustat(new_decode_dev(dev), &sbuf);
         if (err)
                 return err;