Btrfs: don't use global block reservation for inode cache truncation
It is very likely that there are lots of subvolumes/snapshots in the filesystem,
so if we use global block reservation to do inode cache truncation, we may hog
all the free space that is reserved in global rsv. So it is better that we do
the free space reservation for inode cache truncation by ourselves.
Cc: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 9818d4a..2c66ddb 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -429,11 +429,12 @@
num_bytes = trans->bytes_reserved;
/*
* 1 item for inode item insertion if need
- * 3 items for inode item update (in the worst case)
+ * 4 items for inode item update (in the worst case)
+ * 1 items for slack space if we need do truncation
* 1 item for free space object
* 3 items for pre-allocation
*/
- trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 8);
+ trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10);
ret = btrfs_block_rsv_add(root, trans->block_rsv,
trans->bytes_reserved,
BTRFS_RESERVE_NO_FLUSH);