--- ./include/linux/fs.h.sbrace 2004-09-14 13:33:55.835241408 +0400
+++ ./include/linux/fs.h 2004-09-14 13:33:20.065679208 +0400
@@ -1129,6 +1129,7 @@ struct super_block *sget(struct file_sys
struct super_block *get_sb_pseudo(struct file_system_type *, char *,
struct super_operations *ops, unsigned long);
int __put_super(struct super_block *sb);
+int __put_super_and_need_restart(struct super_block *sb);
void unnamed_dev_init(void);
/* Alas, no aliases. Too much hassle with bringing module.h everywhere */
--- ./fs/super.c.sbrace 2004-08-14 14:55:22.000000000 +0400
+++ ./fs/super.c 2004-09-14 13:20:22.365907544 +0400
@@ -116,6 +116,27 @@ int __put_super(struct super_block *sb)
return ret;
}
+/*
+ * Drop a superblock's refcount.
+ * Returns non-zero if the superblock is about to be destroyed and
+ * at least is already removed from super_blocks list, so if we are
+ * making a loop through super blocks then we need to restart.
+ * The caller must hold sb_lock.
+ */
+int __put_super_and_need_restart(struct super_block *sb)
+{
+ /* check for race with generic_shutdown_super() */
+ if (list_empty(&sb->s_list)) {
+ /* super block is removed, need to restart... */
+ __put_super(sb);
+ return 1;
+ }
+ /* can't be the last, since s_list is still in use */
+ sb->s_count--;
+ BUG_ON(sb->s_count == 0);
+ return 0;
+}
+
/**
* put_super - drop a temporary reference to superblock
* @s: superblock in question
@@ -229,7 +250,8 @@ void generic_shutdown_super(struct super
unlock_super(sb);
}
spin_lock(&sb_lock);
- list_del(&sb->s_list);
+ /* should be initialized for __put_super_and_need_restart() */
+ list_del_init(&sb->s_list);
list_del(&sb->s_instances);
spin_unlock(&sb_lock);
up_write(&sb->s_umount);
@@ -282,7 +304,7 @@ retry:
}
s->s_type = type;
strlcpy(s->s_id, type->name, sizeof(s->s_id));
- list_add(&s->s_list, super_blocks.prev);
+ list_add_tail(&s->s_list, &super_blocks);
list_add(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(type);
--- ./fs/fs-writeback.c.sbrace 2004-08-14 14:56:24.000000000 +0400
+++ ./fs/fs-writeback.c 2004-09-14 13:53:44.258573600 +0400
@@ -412,7 +412,7 @@ restart:
up_read(&sb->s_umount);
}
spin_lock(&sb_lock);
- if (__put_super(sb))
+ if (__put_super_and_need_restart(sb))
goto restart;
}
if (wbc->nr_to_write <= 0)