Btrfs: improve the noflush reservation

In some places(such as: evicting inode), we just can not flush the reserved
space of delalloc, flushing the delayed directory index and delayed inode
is OK, but we don't try to flush those things and just go back when there is
no enough space to be reserved. This patch fixes this problem.

We defined 3 types of the flush operations: NO_FLUSH, FLUSH_LIMIT and FLUSH_ALL.
If we can in the transaction, we should not flush anything, or the deadlock
would happen, so use NO_FLUSH. If we flushing the reserved space of delalloc
would cause deadlock, use FLUSH_LIMIT. In the other cases, FLUSH_ALL is used,
and we will flush all things.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index b1a1c929ba80..d26f67a59e36 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -434,8 +434,9 @@ int btrfs_save_ino_cache(struct btrfs_root *root,
          * 3 items for pre-allocation
          */
         trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 8);
-        ret = btrfs_block_rsv_add_noflush(root, trans->block_rsv,
-                                          trans->bytes_reserved);
+        ret = btrfs_block_rsv_add(root, trans->block_rsv,
+                                  trans->bytes_reserved,
+                                  BTRFS_RESERVE_NO_FLUSH);
         if (ret)
                 goto out;
         trace_btrfs_space_reservation(root->fs_info, "ino_cache",