btrfs: move ordered_extent internal sanity checks into btrfs_split_ordered_extent

Move the three checks that are about ordered extent internal sanity
checking into btrfs_split_ordered_extent instead of doing them in the
higher level btrfs_extract_ordered_extent routine.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -2646,18 +2646,6 @@ blk_status_t btrfs_extract_ordered_extent(struct btrfs_bio *bbio)
 	if (ordered->disk_num_bytes == len)
 		goto out;
 
-	/* We cannot split once end_bio'd ordered extent */
-	if (WARN_ON_ONCE(ordered->bytes_left != ordered->disk_num_bytes)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	/* We cannot split a compressed ordered extent */
-	if (WARN_ON_ONCE(ordered->disk_num_bytes != ordered->num_bytes)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	ordered_end = ordered->disk_bytenr + ordered->disk_num_bytes;
 	/* bio must be in one ordered extent */
 	if (WARN_ON_ONCE(start < ordered->disk_bytenr || end > ordered_end)) {
@@ -2665,12 +2653,6 @@ blk_status_t btrfs_extract_ordered_extent(struct btrfs_bio *bbio)
 		goto out;
 	}
 
-	/* Checksum list should be empty */
-	if (WARN_ON_ONCE(!list_empty(&ordered->list))) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	file_len = ordered->num_bytes;
 	pre = start - ordered->disk_bytenr;
 	post = ordered_end - end;

fs/btrfs/ordered-data.c

@@ -1149,6 +1149,16 @@ int btrfs_split_ordered_extent(struct btrfs_ordered_extent *ordered, u64 pre,
 
 	trace_btrfs_ordered_extent_split(BTRFS_I(inode), ordered);
 
+	/* We cannot split once ordered extent is past end_bio. */
+	if (WARN_ON_ONCE(ordered->bytes_left != ordered->disk_num_bytes))
+		return -EINVAL;
+	/* We cannot split a compressed ordered extent. */
+	if (WARN_ON_ONCE(ordered->disk_num_bytes != ordered->num_bytes))
+		return -EINVAL;
+	/* Checksum list should be empty. */
+	if (WARN_ON_ONCE(!list_empty(&ordered->list)))
+		return -EINVAL;
+
 	spin_lock_irq(&tree->lock);
 	/* Remove from tree once */
 	node = &ordered->rb_node;