sysfs: Basic support for multiple super blocks

Add all of the necessary bioler plate to support
multiple superblocks in sysfs.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 776137828dcaf6587bed86fb7cf16c7a3c89ffe0..db0b1f2138af94e58dd6e8796863c08d1955b52d 100644 (file)
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -72,16 +72,70 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
        return 0;
 }
 
+static int sysfs_test_super(struct super_block *sb, void *data)
+{
+       struct sysfs_super_info *sb_info = sysfs_info(sb);
+       struct sysfs_super_info *info = data;
+       int found = 1;
+       return found;
+}
+
+static int sysfs_set_super(struct super_block *sb, void *data)
+{
+       int error;
+       error = set_anon_super(sb, data);
+       if (!error)
+               sb->s_fs_info = data;
+       return error;
+}
+
 static int sysfs_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
-       return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
+       struct sysfs_super_info *info;
+       struct super_block *sb;
+       int error;
+
+       error = -ENOMEM;
+       info = kzalloc(sizeof(*info), GFP_KERNEL);
+       if (!info)
+               goto out;
+       sb = sget(fs_type, sysfs_test_super, sysfs_set_super, info);
+       if (IS_ERR(sb) || sb->s_fs_info != info)
+               kfree(info);
+       if (IS_ERR(sb)) {
+               kfree(info);
+               error = PTR_ERR(sb);
+               goto out;
+       }
+       if (!sb->s_root) {
+               sb->s_flags = flags;
+               error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
+               if (error) {
+                       deactivate_locked_super(sb);
+                       goto out;
+               }
+               sb->s_flags |= MS_ACTIVE;
+       }
+
+       simple_set_mnt(mnt, sb);
+       error = 0;
+out:
+       return error;
+}
+
+static void sysfs_kill_sb(struct super_block *sb)
+{
+       struct sysfs_super_info *info = sysfs_info(sb);
+
+       kill_anon_super(sb);
+       kfree(info);
 }
 
 static struct file_system_type sysfs_fs_type = {
        .name           = "sysfs",
        .get_sb         = sysfs_get_sb,
-       .kill_sb        = kill_anon_super,
+       .kill_sb        = sysfs_kill_sb,
 };
 
 int __init sysfs_init(void)

diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 30f5a44fb5d3a074b36c6c4520e40e5aa79cdf9c..030a39dbb02c7b8578109065f45cf4170adabe65 100644 (file)
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -114,6 +114,9 @@ struct sysfs_addrm_cxt {
 /*
  * mount.c
  */
+struct sysfs_super_info {
+};
+#define sysfs_info(SB) ((struct sysfs_super_info *)(SB->s_fs_info))
 extern struct sysfs_dirent sysfs_root;
 extern struct kmem_cache *sysfs_dir_cachep;