async: make the final inode deletion an asynchronous event

this makes "rm -rf" on a (names cached) kernel tree go from
11.6 to 8.6 seconds on an ext3 filesystem

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/super.c b/fs/super.c
index ddba069d7a99..cb20744ec789 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -38,6 +38,7 @@
 #include <linux/kobject.h>
 #include <linux/mutex.h>
 #include <linux/file.h>
+#include <linux/async.h>
 #include <asm/uaccess.h>
 #include "internal.h"
 
@@ -71,6 +72,7 @@ static struct super_block *alloc_super(struct file_system_type *type)
                 INIT_HLIST_HEAD(&s->s_anon);
                 INIT_LIST_HEAD(&s->s_inodes);
                 INIT_LIST_HEAD(&s->s_dentry_lru);
+                INIT_LIST_HEAD(&s->s_async_list);
                 init_rwsem(&s->s_umount);
                 mutex_init(&s->s_lock);
                 lockdep_set_class(&s->s_umount, &type->s_umount_key);
@@ -289,11 +291,18 @@ void generic_shutdown_super(struct super_block *sb)
 {
         const struct super_operations *sop = sb->s_op;
 
+
         if (sb->s_root) {
                 shrink_dcache_for_umount(sb);
                 fsync_super(sb);
                 lock_super(sb);
                 sb->s_flags &= ~MS_ACTIVE;
+
+                /*
+                 * wait for asynchronous fs operations to finish before going further
+                 */
+                async_synchronize_full_special(&sb->s_async_list);
+
                 /* bad name - it should be evict_inodes() */
                 invalidate_inodes(sb);
                 lock_kernel();
@@ -449,6 +458,7 @@ void sync_filesystems(int wait)
                 if (sb->s_flags & MS_RDONLY)
                         continue;
                 sb->s_need_sync_fs = 1;
+                async_synchronize_full_special(&sb->s_async_list);
         }
 
 restart: