[PATCH v2 1/8] btrfs: remove the alignment checks in end_bbio_data_read

[Qu Wenruo <wqu@suse.com>]

From: Christoph Hellwig <hch@lst.de>

end_bbio_data_read() checks that each iterated folio fragment is aligned
and justifies that with block drivers advancing the bio.  But block
driver only advance bi_iter, while end_bbio_data_read() uses
bio_for_each_folio_all() to iterate the immutable bi_io_vec array that
can't be changed by drivers at all.

Furthermore btrfs has already did the alignment check of the file
offset inside submit_one_sector(), and the size is fixed to fs block
size, there is no need to re-do the alignment check again inside the
endio function.

So just remove the unnecessary alignment check along with the incorrect
comment.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/extent_io.c | 27 +++------------------------
 1 file changed, 3 insertions(+), 24 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 5f08615b334f..f2fafad1add0 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -499,43 +499,22 @@ static void end_bbio_data_read(struct btrfs_bio *bbio)
 	struct btrfs_fs_info *fs_info = bbio->fs_info;
 	struct bio *bio = &bbio->bio;
 	struct folio_iter fi;
-	const u32 sectorsize = fs_info->sectorsize;
 
 	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_folio_all(fi, &bbio->bio) {
 		bool uptodate = !bio->bi_status;
 		struct folio *folio = fi.folio;
 		struct inode *inode = folio->mapping->host;
-		u64 start;
-		u64 end;
-		u32 len;
+		u64 start = folio_pos(folio) + fi.offset;
 
 		btrfs_debug(fs_info,
 			"%s: bi_sector=%llu, err=%d, mirror=%u",
 			__func__, bio->bi_iter.bi_sector, bio->bi_status,
 			bbio->mirror_num);
 
-		/*
-		 * We always issue full-sector reads, but if some block in a
-		 * folio fails to read, blk_update_request() will advance
-		 * bv_offset and adjust bv_len to compensate.  Print a warning
-		 * for unaligned offsets, and an error if they don't add up to
-		 * a full sector.
-		 */
-		if (!IS_ALIGNED(fi.offset, sectorsize))
-			btrfs_err(fs_info,
-		"partial page read in btrfs with offset %zu and length %zu",
-				  fi.offset, fi.length);
-		else if (!IS_ALIGNED(fi.offset + fi.length, sectorsize))
-			btrfs_info(fs_info,
-		"incomplete page read with offset %zu and length %zu",
-				   fi.offset, fi.length);
-
-		start = folio_pos(folio) + fi.offset;
-		end = start + fi.length - 1;
-		len = fi.length;
 
 		if (likely(uptodate)) {
+			u64 end = start + fi.length - 1;
 			loff_t i_size = i_size_read(inode);
 
 			/*
@@ -560,7 +539,7 @@ static void end_bbio_data_read(struct btrfs_bio *bbio)
 		}
 
 		/* Update page status and unlock. */
-		end_folio_read(folio, uptodate, start, len);
+		end_folio_read(folio, uptodate, start, fi.length);
 	}
 	bio_put(bio);
 }
-- 
2.49.0