[PATCH 1/8] btrfs: quit early if the fs has no RAID56 support for raid56 related checks

[Christoph Hellwig <hch@lst.de>]

From: Qu Wenruo <wqu@suse.com>

The following functions do special handling for RAID56 chunks:

- btrfs_is_parity_mirror()
  Check if the range is in RAID56 chunks.

- btrfs_full_stripe_len()
  Either return sectorsize for non-RAID56 profiles or full stripe length
  for RAID56 chunks.

But if a filesystem without any RAID56 chunks, it will not have RAID56
incompt flags, and we can skip the chunk tree looking up completely.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/volumes.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 58f3eece8a48c..0819db46dbc42 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5769,6 +5769,9 @@ unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
 	struct map_lookup *map;
 	unsigned long len = fs_info->sectorsize;
 
+	if (!btrfs_fs_incompat(fs_info, RAID56))
+		return len;
+
 	em = btrfs_get_chunk_map(fs_info, logical, len);
 
 	if (!WARN_ON(IS_ERR(em))) {
@@ -5786,6 +5789,9 @@ int btrfs_is_parity_mirror(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 	struct map_lookup *map;
 	int ret = 0;
 
+	if (!btrfs_fs_incompat(fs_info, RAID56))
+		return 0;
+
 	em = btrfs_get_chunk_map(fs_info, logical, len);
 
 	if(!WARN_ON(IS_ERR(em))) {
-- 
2.30.2