From: Josef Bacik <josef@toxicpanda.com>
Date: Tue, 21 Jul 2020 10:22:23 -0400
Subject: btrfs: add flushing states for handling data reservations
Git-commit: 058e6d1d267fe9c7e072533d2e1469d93aec3ec7
Patch-mainline: v5.10-rc1
References: bsc#1135481

Currently the way we do data reservations is by seeing if we have enough
space in our space_info.  If we do not and we're a normal inode we'll

1) Attempt to force a chunk allocation until we can't anymore.
2) If that fails we'll flush delalloc, then commit the transaction, then
   run the delayed iputs.

If we are a free space inode we're only allowed to force a chunk
allocation.  In order to use the normal flushing mechanism we need to
encode this into a flush state array for normal inodes.  Since both will
start with allocating chunks until the space info is full there is no
need to add this as a flush state, this will be handled specially.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/ctree.h      |    2 ++
 fs/btrfs/space-info.c |    6 ++++++
 2 files changed, 8 insertions(+)

--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2562,6 +2562,8 @@ enum btrfs_reserve_flush_enum {
 	BTRFS_RESERVE_FLUSH_LIMIT,
 	BTRFS_RESERVE_FLUSH_EVICT,
 	BTRFS_RESERVE_FLUSH_ALL,
+	BTRFS_RESERVE_FLUSH_DATA,
+	BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE,
 	BTRFS_RESERVE_FLUSH_ALL_STEAL,
 };
 
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -892,6 +892,12 @@ static const enum btrfs_flush_state evic
 	COMMIT_TRANS,
 };
 
+static const enum btrfs_flush_state data_flush_states[] = {
+	FLUSH_DELALLOC_WAIT,
+	COMMIT_TRANS,
+	RUN_DELAYED_IPUTS,
+};
+
 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
 				struct btrfs_space_info *space_info,
 				struct reserve_ticket *ticket,