[PATCH 2/5] btrfs: push the NODATASUM check into btrfs_lookup_bio_sums

[Josef Bacik <josef@toxicpanda.com>]

When we move to being able to handle NULL csum_roots it'll be cleaner to
just check in btrfs_lookup_bio_sums instead of at all of the caller
locations, so push the NODATASUM check into it as well so it's unified.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/compression.c | 14 +++++---------
 fs/btrfs/file-item.c   |  3 +++
 fs/btrfs/inode.c       | 12 +++++++++---
 3 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index eeface30facd..7e1eb57b923c 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -722,11 +722,9 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 			 */
 			refcount_inc(&cb->pending_bios);
 
-			if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
-				ret = btrfs_lookup_bio_sums(inode, comp_bio,
-							    (u64)-1, sums);
-				BUG_ON(ret); /* -ENOMEM */
-			}
+			ret = btrfs_lookup_bio_sums(inode, comp_bio, (u64)-1,
+						    sums);
+			BUG_ON(ret); /* -ENOMEM */
 
 			nr_sectors = DIV_ROUND_UP(comp_bio->bi_iter.bi_size,
 						  fs_info->sectorsize);
@@ -751,10 +749,8 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 	ret = btrfs_bio_wq_end_io(fs_info, comp_bio, BTRFS_WQ_ENDIO_DATA);
 	BUG_ON(ret); /* -ENOMEM */
 
-	if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
-		ret = btrfs_lookup_bio_sums(inode, comp_bio, (u64)-1, sums);
-		BUG_ON(ret); /* -ENOMEM */
-	}
+	ret = btrfs_lookup_bio_sums(inode, comp_bio, (u64)-1, sums);
+	BUG_ON(ret); /* -ENOMEM */
 
 	ret = btrfs_map_bio(fs_info, comp_bio, mirror_num);
 	if (ret) {
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 8f4f2bd6d9b9..8083d71d6af6 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -272,6 +272,9 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
 	int count = 0;
 	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 
+	if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
+		return BLK_STS_OK;
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return BLK_STS_RESOURCE;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d526833b5ec0..d262944c4297 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2202,7 +2202,12 @@ blk_status_t btrfs_submit_data_bio(struct inode *inode, struct bio *bio,
 							   mirror_num,
 							   bio_flags);
 			goto out;
-		} else if (!skip_sum) {
+		} else {
+			/*
+			 * Lookup bio sums does extra checks around whether we
+			 * need to csum or not, which is why we ignore skip_sum
+			 * here.
+			 */
 			ret = btrfs_lookup_bio_sums(inode, bio, (u64)-1, NULL);
 			if (ret)
 				goto out;
@@ -7781,7 +7786,6 @@ static blk_qc_t btrfs_submit_direct(struct inode *inode, struct iomap *iomap,
 		struct bio *dio_bio, loff_t file_offset)
 {
 	const bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
-	const bool csum = !(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM);
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	const bool raid56 = (btrfs_data_alloc_profile(fs_info) &
 			     BTRFS_BLOCK_GROUP_RAID56_MASK);
@@ -7808,10 +7812,12 @@ static blk_qc_t btrfs_submit_direct(struct inode *inode, struct iomap *iomap,
 		return BLK_QC_T_NONE;
 	}
 
-	if (!write && csum) {
+	if (!write) {
 		/*
 		 * Load the csums up front to reduce csum tree searches and
 		 * contention when submitting bios.
+		 *
+		 * If we have csums disabled this will do nothing.
 		 */
 		status = btrfs_lookup_bio_sums(inode, dio_bio, file_offset,
 					       dip->csums);
-- 
2.26.2