1 files changed, 33 insertions, 0 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index c77b848c3d43..f5f8b15a6e40 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -547,6 +547,39 @@ repeat:
         return err;
 }
 
+void do_thaw_all(unsigned long unused)
+{
+        struct super_block *sb;
+        char b[BDEVNAME_SIZE];
+
+        spin_lock(&sb_lock);
+restart:
+        list_for_each_entry(sb, &super_blocks, s_list) {
+                sb->s_count++;
+                spin_unlock(&sb_lock);
+                down_read(&sb->s_umount);
+                while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))
+                        printk(KERN_WARNING "Emergency Thaw on %s\n",
+                               bdevname(sb->s_bdev, b));
+                up_read(&sb->s_umount);
+                spin_lock(&sb_lock);
+                if (__put_super_and_need_restart(sb))
+                        goto restart;
+        }
+        spin_unlock(&sb_lock);
+        printk(KERN_WARNING "Emergency Thaw complete\n");
+}
+
+/**
+ * emergency_thaw_all -- forcibly thaw every frozen filesystem
+ *
+ * Used for emergency unfreeze of all filesystems via SysRq
+ */
+void emergency_thaw_all(void)
+{
+        pdflush_operation(do_thaw_all, 0);
+}
+
 /**
  * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers
  * @mapping: the mapping which wants those buffers written