btrfs: give struct btrfs_bio a real end_io handler

Currently btrfs_bio end I/O handling is a bit of a mess.  The bi_end_io
handler and bi_private pointer of the embedded struct bio are both used
to handle the completion of the high-level btrfs_bio and for the I/O
completion for the low-level device that the embedded bio ends up being
sent to.

To support this bi_end_io and bi_private are saved into the
btrfs_io_context structure and then restored after the bio sent to the
underlying device has completed the actual I/O.

Untangle this by adding an end I/O handler and private data to struct
btrfs_bio for the high-level btrfs_bio based completions, and leave the
actual bio bi_end_io handler and bi_private pointer entirely to the
low-level device I/O.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 17 insertions, 24 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index a7f8a09601c9..1c77de3239bc 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -152,9 +152,7 @@ static void finish_compressed_bio_read(struct compressed_bio *cb)
 	}
 
 	/* Do io completion on the original bio */
-	if (cb->status != BLK_STS_OK)
-		cb->orig_bio->bi_status = cb->status;
-	bio_endio(cb->orig_bio);
+	btrfs_bio_end_io(btrfs_bio(cb->orig_bio), cb->status);
 
 	/* Finally free the cb struct */
 	kfree(cb->compressed_pages);
@@ -166,16 +164,15 @@ static void finish_compressed_bio_read(struct compressed_bio *cb)
  * before decompressing it into the original bio and freeing the uncompressed
  * pages.
  */
-static void end_compressed_bio_read(struct bio *bio)
+static void end_compressed_bio_read(struct btrfs_bio *bbio)
 {
-	struct compressed_bio *cb = bio->bi_private;
+	struct compressed_bio *cb = bbio->private;
 	struct inode *inode = cb->inode;
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct btrfs_inode *bi = BTRFS_I(inode);
 	bool csum = !(bi->flags & BTRFS_INODE_NODATASUM) &&
 		    !test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state);
-	blk_status_t status = bio->bi_status;
-	struct btrfs_bio *bbio = btrfs_bio(bio);
+	blk_status_t status = bbio->bio.bi_status;
 	struct bvec_iter iter;
 	struct bio_vec bv;
 	u32 offset;
@@ -209,7 +206,7 @@ static void end_compressed_bio_read(struct bio *bio)
 	if (refcount_dec_and_test(&cb->pending_ios))
 		finish_compressed_bio_read(cb);
 	btrfs_bio_free_csum(bbio);
-	bio_put(bio);
+	bio_put(&bbio->bio);
 }
 
 /*
@@ -301,20 +298,20 @@ static void btrfs_finish_compressed_write_work(struct work_struct *work)
  * This also calls the writeback end hooks for the file pages so that metadata
  * and checksums can be updated in the file.
  */
-static void end_compressed_bio_write(struct bio *bio)
+static void end_compressed_bio_write(struct btrfs_bio *bbio)
 {
-	struct compressed_bio *cb = bio->bi_private;
+	struct compressed_bio *cb = bbio->private;
 
-	if (bio->bi_status)
-		cb->status = bio->bi_status;
+	if (bbio->bio.bi_status)
+		cb->status = bbio->bio.bi_status;
 
 	if (refcount_dec_and_test(&cb->pending_ios)) {
 		struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb);
 
-		btrfs_record_physical_zoned(cb->inode, cb->start, bio);
+		btrfs_record_physical_zoned(cb->inode, cb->start, &bbio->bio);
 		queue_work(fs_info->compressed_write_workers, &cb->write_end_work);
 	}
-	bio_put(bio);
+	bio_put(&bbio->bio);
 }
 
 /*
@@ -335,7 +332,8 @@ static void end_compressed_bio_write(struct bio *bio)
 
 
 static struct bio *alloc_compressed_bio(struct compressed_bio *cb, u64 disk_bytenr,
-					blk_opf_t opf, bio_end_io_t endio_func,
+					blk_opf_t opf,
+					btrfs_bio_end_io_t endio_func,
 					u64 *next_stripe_start)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb);
@@ -344,10 +342,8 @@ static struct bio *alloc_compressed_bio(struct compressed_bio *cb, u64 disk_byte
 	struct bio *bio;
 	int ret;
 
-	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf);
+	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, endio_func, cb);
 	bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
-	bio->bi_private = cb;
-	bio->bi_end_io = endio_func;
 
 	em = btrfs_get_chunk_map(fs_info, disk_bytenr, fs_info->sectorsize);
 	if (IS_ERR(em)) {
@@ -476,8 +472,7 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
 			if (!skip_sum) {
 				ret = btrfs_csum_one_bio(inode, bio, start, true);
 				if (ret) {
-					bio->bi_status = ret;
-					bio_endio(bio);
+					btrfs_bio_end_io(btrfs_bio(bio), ret);
 					break;
 				}
 			}
@@ -797,8 +792,7 @@ void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 
 			ret = btrfs_lookup_bio_sums(inode, comp_bio, NULL);
 			if (ret) {
-				comp_bio->bi_status = ret;
-				bio_endio(comp_bio);
+				btrfs_bio_end_io(btrfs_bio(comp_bio), ret);
 				break;
 			}
 
@@ -824,8 +818,7 @@ fail:
 	kfree(cb);
 out:
 	free_extent_map(em);
-	bio->bi_status = ret;
-	bio_endio(bio);
+	btrfs_bio_end_io(btrfs_bio(bio), ret);
 	return;
 }