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, 8 insertions, 4 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 776f0aa128fc..242d6de4d8eb 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2074,7 +2074,8 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
                 BUG_ON(IS_ERR(trans));
                 trans->block_rsv = rc->block_rsv;
 
-                ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved);
+                ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
+                                             BTRFS_RESERVE_FLUSH_ALL);
                 if (ret) {
                         BUG_ON(ret != -EAGAIN);
                         ret = btrfs_commit_transaction(trans, root);
@@ -2184,7 +2185,8 @@ int prepare_to_merge(struct reloc_control *rc, int err)
 again:
         if (!err) {
                 num_bytes = rc->merging_rsv_size;
-                ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
+                ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
+                                          BTRFS_RESERVE_FLUSH_ALL);
                 if (ret)
                         err = ret;
         }
@@ -2459,7 +2461,8 @@ static int reserve_metadata_space(struct btrfs_trans_handle *trans,
         num_bytes = calcu_metadata_size(rc, node, 1) * 2;
 
         trans->block_rsv = rc->block_rsv;
-        ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
+        ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
+                                  BTRFS_RESERVE_FLUSH_ALL);
         if (ret) {
                 if (ret == -EAGAIN)
                         rc->commit_transaction = 1;
@@ -3685,7 +3688,8 @@ int prepare_to_relocate(struct reloc_control *rc)
          * is no reservation in transaction handle.
          */
         ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
-                                  rc->extent_root->nodesize * 256);
+                                  rc->extent_root->nodesize * 256,
+                                  BTRFS_RESERVE_FLUSH_ALL);
         if (ret)
                 return ret;