btrfs: split zone append bios in btrfs_submit_bio

The current btrfs zoned device support is a little cumbersome in the data
I/O path as it requires the callers to not issue I/O larger than the
supported ZONE_APPEND size of the underlying device.  This leads to a lot
of extra accounting.  Instead change btrfs_submit_bio so that it can take
write bios of arbitrary size and form from the upper layers, and just
split them internally to the ZONE_APPEND queue limits.  Then remove all
the upper layer warts catering to limited write sized on zoned devices,
including the extra refcount in the compressed_bio.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-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, 15 insertions, 57 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 34c044501f8a..e2816b86311a 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -896,7 +896,6 @@ static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
 	u32 real_size;
 	const sector_t sector = disk_bytenr >> SECTOR_SHIFT;
 	bool contig = false;
-	int ret;
 
 	ASSERT(bio);
 	/* The limit should be calculated when bio_ctrl->bio is allocated */
@@ -945,12 +944,7 @@ static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
 	if (real_size == 0)
 		return 0;
 
-	if (bio_op(bio) == REQ_OP_ZONE_APPEND)
-		ret = bio_add_zone_append_page(bio, page, real_size, pg_offset);
-	else
-		ret = bio_add_page(bio, page, real_size, pg_offset);
-
-	return ret;
+	return bio_add_page(bio, page, real_size, pg_offset);
 }
 
 static void calc_bio_boundaries(struct btrfs_bio_ctrl *bio_ctrl,
@@ -965,7 +959,7 @@ static void calc_bio_boundaries(struct btrfs_bio_ctrl *bio_ctrl,
 	 * them.
 	 */
 	if (bio_ctrl->compress_type == BTRFS_COMPRESS_NONE &&
-	    bio_op(bio_ctrl->bio) == REQ_OP_ZONE_APPEND) {
+	    btrfs_use_zone_append(inode, logical)) {
 		ordered = btrfs_lookup_ordered_extent(inode, file_offset);
 		if (ordered) {
 			bio_ctrl->len_to_oe_boundary = min_t(u32, U32_MAX,
@@ -979,16 +973,14 @@ static void calc_bio_boundaries(struct btrfs_bio_ctrl *bio_ctrl,
 	bio_ctrl->len_to_oe_boundary = U32_MAX;
 }
 
-static int alloc_new_bio(struct btrfs_inode *inode,
-			 struct btrfs_bio_ctrl *bio_ctrl,
-			 struct writeback_control *wbc,
-			 blk_opf_t opf,
-			 u64 disk_bytenr, u32 offset, u64 file_offset,
-			 enum btrfs_compression_type compress_type)
+static void alloc_new_bio(struct btrfs_inode *inode,
+			  struct btrfs_bio_ctrl *bio_ctrl,
+			  struct writeback_control *wbc, blk_opf_t opf,
+			  u64 disk_bytenr, u32 offset, u64 file_offset,
+			  enum btrfs_compression_type compress_type)
 {
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	struct bio *bio;
-	int ret;
 
 	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, inode, bio_ctrl->end_io_func,
 			      NULL);
@@ -1006,40 +998,14 @@ static int alloc_new_bio(struct btrfs_inode *inode,
 
 	if (wbc) {
 		/*
-		 * For Zone append we need the correct block_device that we are
-		 * going to write to set in the bio to be able to respect the
-		 * hardware limitation.  Look it up here:
+		 * Pick the last added device to support cgroup writeback.  For
+		 * multi-device file systems this means blk-cgroup policies have
+		 * to always be set on the last added/replaced device.
+		 * This is a bit odd but has been like that for a long time.
 		 */
-		if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
-			struct btrfs_device *dev;
-
-			dev = btrfs_zoned_get_device(fs_info, disk_bytenr,
-						     fs_info->sectorsize);
-			if (IS_ERR(dev)) {
-				ret = PTR_ERR(dev);
-				goto error;
-			}
-
-			bio_set_dev(bio, dev->bdev);
-		} else {
-			/*
-			 * Otherwise pick the last added device to support
-			 * cgroup writeback.  For multi-device file systems this
-			 * means blk-cgroup policies have to always be set on the
-			 * last added/replaced device.  This is a bit odd but has
-			 * been like that for a long time.
-			 */
-			bio_set_dev(bio, fs_info->fs_devices->latest_dev->bdev);
-		}
+		bio_set_dev(bio, fs_info->fs_devices->latest_dev->bdev);
 		wbc_init_bio(wbc, bio);
-	} else {
-		ASSERT(bio_op(bio) != REQ_OP_ZONE_APPEND);
 	}
-	return 0;
-error:
-	bio_ctrl->bio = NULL;
-	btrfs_bio_end_io(btrfs_bio(bio), errno_to_blk_status(ret));
-	return ret;
 }
 
 /*
@@ -1065,7 +1031,6 @@ static int submit_extent_page(blk_opf_t opf,
 			      enum btrfs_compression_type compress_type,
 			      bool force_bio_submit)
 {
-	int ret = 0;
 	struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
 	unsigned int cur = pg_offset;
 
@@ -1085,12 +1050,9 @@ static int submit_extent_page(blk_opf_t opf,
 
 		/* Allocate new bio if needed */
 		if (!bio_ctrl->bio) {
-			ret = alloc_new_bio(inode, bio_ctrl, wbc, opf,
-					    disk_bytenr, offset,
-					    page_offset(page) + cur,
-					    compress_type);
-			if (ret < 0)
-				return ret;
+			alloc_new_bio(inode, bio_ctrl, wbc, opf, disk_bytenr,
+				      offset, page_offset(page) + cur,
+				      compress_type);
 		}
 		/*
 		 * We must go through btrfs_bio_add_page() to ensure each
@@ -1647,10 +1609,6 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
 		 * find_next_dirty_byte() are all exclusive
 		 */
 		iosize = min(min(em_end, end + 1), dirty_range_end) - cur;
-
-		if (btrfs_use_zone_append(inode, em->block_start))
-			op = REQ_OP_ZONE_APPEND;
-
 		free_extent_map(em);
 		em = NULL;