Re: [RFC PATCH v3 04/12] btrfs: get rid of trivial __btrfs_lookup_bio_sums() wrappers

On Tue, Nov 26, 2019 at 03:56:31PM +0200, Nikolay Borisov wrote:

On 20.11.19 г. 20:24 ч., Omar Sandoval wrote:

quoted

From: Omar Sandoval <redacted>

Currently, we have two wrappers for __btrfs_lookup_bio_sums():
btrfs_lookup_bio_sums_dio(), which is used for direct I/O, and
btrfs_lookup_bio_sums(), which is used everywhere else. The only
difference is that the _dio variant looks up csums starting at the given
offset instead of using the page index, which isn't actually direct
I/O-specific. Let's clean up the signature and return value of
__btrfs_lookup_bio_sums(), rename it to btrfs_lookup_bio_sums(), and get
rid of the trivial helpers.

Signed-off-by: Omar Sandoval <redacted>

Overall looks good but 2 nits, see below.

In any case:

Reviewed-by: Nikolay Borisov <redacted>

Thanks!

quoted

---
 fs/btrfs/compression.c |  4 ++--
 fs/btrfs/ctree.h       |  4 +---
 fs/btrfs/file-item.c   | 35 +++++++++++++++++------------------
 fs/btrfs/inode.c       |  6 +++---
 4 files changed, 23 insertions(+), 26 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index b05b361e2062..4df6f0c58dc9 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c

@@ -660,7 +660,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 
 			if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
 				ret = btrfs_lookup_bio_sums(inode, comp_bio,
-							    sums);
+							    false, 0, sums);
 				BUG_ON(ret); /* -ENOMEM */
 			}
 

@@ -689,7 +689,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 	BUG_ON(ret); /* -ENOMEM */
 
 	if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
-		ret = btrfs_lookup_bio_sums(inode, comp_bio, sums);
+		ret = btrfs_lookup_bio_sums(inode, comp_bio, false, 0, sums);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index fe2b8765d9e6..4bc40bf49b0e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h

@@ -2787,9 +2787,7 @@ struct btrfs_dio_private;
 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 		    struct btrfs_fs_info *fs_info, u64 bytenr, u64 len);
 blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
-				   u8 *dst);
-blk_status_t btrfs_lookup_bio_sums_dio(struct inode *inode, struct bio *bio,
-			      u64 logical_offset);
+				   bool at_offset, u64 offset, u8 *dst);
 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root,
 			     u64 objectid, u64 pos,

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 1a599f50837b..a87c40502267 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c

@@ -148,8 +148,21 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-static blk_status_t __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
-				   u64 logical_offset, u8 *dst, int dio)
+/**
+ * btrfs_lookup_bio_sums - Look up checksums for a bio.
+ * @inode: inode that the bio is for.
+ * @bio: bio embedded in btrfs_io_bio.
+ * @at_offset: If true, look up checksums for the extent at @c offset.

nit: that @c is an editing artifact?

Oops, I mixed up kernel-doc with Doxygen. Fixed, thanks.

On the other hand rather than
having an explicit bool signifying whether we want a specific offset
can't we simply check if offset is != 0 ?

Zero is a perfectly valid offset to have an extent at, but we could do
(u64)-1 instead. I'm not sure what's cleaner.