Btrfs: Avoid superfluous tree-log writeout

We allow two log transactions at a time, but use same flag
to mark dirty tree-log btree blocks. So we may flush dirty
blocks belonging to newer log transaction when committing a
log transaction. This patch fixes the issue by using two
flags to mark dirty tree-log btree blocks.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index c207e8c32c9..b7b22c344b6 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -354,7 +354,7 @@ int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
  * those extents are sent to disk but does not wait on them
  */
 int btrfs_write_marked_extents(struct btrfs_root *root,
-                               struct extent_io_tree *dirty_pages)
+                               struct extent_io_tree *dirty_pages, int mark)
 {
         int ret;
         int err = 0;
@@ -367,7 +367,7 @@ int btrfs_write_marked_extents(struct btrfs_root *root,
 
         while (1) {
                 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
-                                            EXTENT_DIRTY);
+                                            mark);
                 if (ret)
                         break;
                 while (start <= end) {
@@ -413,7 +413,7 @@ int btrfs_write_marked_extents(struct btrfs_root *root,
  * on all the pages and clear them from the dirty pages state tree
  */
 int btrfs_wait_marked_extents(struct btrfs_root *root,
-                              struct extent_io_tree *dirty_pages)
+                              struct extent_io_tree *dirty_pages, int mark)
 {
         int ret;
         int err = 0;
@@ -425,12 +425,12 @@ int btrfs_wait_marked_extents(struct btrfs_root *root,
         unsigned long index;
 
         while (1) {
-                ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
-                                            EXTENT_DIRTY);
+                ret = find_first_extent_bit(dirty_pages, start, &start, &end,
+                                            mark);
                 if (ret)
                         break;
 
-                clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
+                clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
                 while (start <= end) {
                         index = start >> PAGE_CACHE_SHIFT;
                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
@@ -460,13 +460,13 @@ int btrfs_wait_marked_extents(struct btrfs_root *root,
  * those extents are on disk for transaction or log commit
  */
 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
-                                        struct extent_io_tree *dirty_pages)
+                                struct extent_io_tree *dirty_pages, int mark)
 {
         int ret;
         int ret2;
 
-        ret = btrfs_write_marked_extents(root, dirty_pages);
-        ret2 = btrfs_wait_marked_extents(root, dirty_pages);
+        ret = btrfs_write_marked_extents(root, dirty_pages, mark);
+        ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
         return ret || ret2;
 }
 
@@ -479,7 +479,8 @@ int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
                 return filemap_write_and_wait(btree_inode->i_mapping);
         }
         return btrfs_write_and_wait_marked_extents(root,
-                                           &trans->transaction->dirty_pages);
+                                           &trans->transaction->dirty_pages,
+                                           EXTENT_DIRTY);
 }
 
 /*