1 files changed, 58 insertions, 7 deletions

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index d6204d1ac47f..83088d96e6c4 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -1599,10 +1599,43 @@ xlog_recover_add_to_trans(
 }
 
 /*
- * Sort the log items in the transaction. Cancelled buffers need
- * to be put first so they are processed before any items that might
- * modify the buffers. If they are cancelled, then the modifications
- * don't need to be replayed.
+ * Sort the log items in the transaction.
+ *
+ * The ordering constraints are defined by the inode allocation and unlink
+ * behaviour. The rules are:
+ *
+ *      1. Every item is only logged once in a given transaction. Hence it
+ *         represents the last logged state of the item. Hence ordering is
+ *         dependent on the order in which operations need to be performed so
+ *         required initial conditions are always met.
+ *
+ *      2. Cancelled buffers are recorded in pass 1 in a separate table and
+ *         there's nothing to replay from them so we can simply cull them
+ *         from the transaction. However, we can't do that until after we've
+ *         replayed all the other items because they may be dependent on the
+ *         cancelled buffer and replaying the cancelled buffer can remove it
+ *         form the cancelled buffer table. Hence they have tobe done last.
+ *
+ *      3. Inode allocation buffers must be replayed before inode items that
+ *         read the buffer and replay changes into it.
+ *
+ *      4. Inode unlink buffers must be replayed after inode items are replayed.
+ *         This ensures that inodes are completely flushed to the inode buffer
+ *         in a "free" state before we remove the unlinked inode list pointer.
+ *
+ * Hence the ordering needs to be inode allocation buffers first, inode items
+ * second, inode unlink buffers third and cancelled buffers last.
+ *
+ * But there's a problem with that - we can't tell an inode allocation buffer
+ * apart from a regular buffer, so we can't separate them. We can, however,
+ * tell an inode unlink buffer from the others, and so we can separate them out
+ * from all the other buffers and move them to last.
+ *
+ * Hence, 4 lists, in order from head to tail:
+ *      - buffer_list for all buffers except cancelled/inode unlink buffers
+ *      - item_list for all non-buffer items
+ *      - inode_buffer_list for inode unlink buffers
+ *      - cancel_list for the cancelled buffers
  */
 STATIC int
 xlog_recover_reorder_trans(
@@ -1612,6 +1645,10 @@ xlog_recover_reorder_trans(
 {
         xlog_recover_item_t     *item, *n;
         LIST_HEAD(sort_list);
+        LIST_HEAD(cancel_list);
+        LIST_HEAD(buffer_list);
+        LIST_HEAD(inode_buffer_list);
+        LIST_HEAD(inode_list);
 
         list_splice_init(&trans->r_itemq, &sort_list);
         list_for_each_entry_safe(item, n, &sort_list, ri_list) {
@@ -1619,12 +1656,18 @@ xlog_recover_reorder_trans(
 
                 switch (ITEM_TYPE(item)) {
                 case XFS_LI_BUF:
-                        if (!(buf_f->blf_flags & XFS_BLF_CANCEL)) {
+                        if (buf_f->blf_flags & XFS_BLF_CANCEL) {
                                 trace_xfs_log_recover_item_reorder_head(log,
                                                         trans, item, pass);
-                                list_move(&item->ri_list, &trans->r_itemq);
+                                list_move(&item->ri_list, &cancel_list);
                                 break;
                         }
+                        if (buf_f->blf_flags & XFS_BLF_INODE_BUF) {
+                                list_move(&item->ri_list, &inode_buffer_list);
+                                break;
+                        }
+                        list_move_tail(&item->ri_list, &buffer_list);
+                        break;
                 case XFS_LI_INODE:
                 case XFS_LI_DQUOT:
                 case XFS_LI_QUOTAOFF:
@@ -1632,7 +1675,7 @@ xlog_recover_reorder_trans(
                 case XFS_LI_EFI:
                         trace_xfs_log_recover_item_reorder_tail(log,
                                                         trans, item, pass);
-                        list_move_tail(&item->ri_list, &trans->r_itemq);
+                        list_move_tail(&item->ri_list, &inode_list);
                         break;
                 default:
                         xfs_warn(log->l_mp,
@@ -1643,6 +1686,14 @@ xlog_recover_reorder_trans(
                 }
         }
         ASSERT(list_empty(&sort_list));
+        if (!list_empty(&buffer_list))
+                list_splice(&buffer_list, &trans->r_itemq);
+        if (!list_empty(&inode_list))
+                list_splice_tail(&inode_list, &trans->r_itemq);
+        if (!list_empty(&inode_buffer_list))
+                list_splice_tail(&inode_buffer_list, &trans->r_itemq);
+        if (!list_empty(&cancel_list))
+                list_splice_tail(&cancel_list, &trans->r_itemq);
         return 0;
 }