bcachefs: Fix read retry path for indirect extents

In the read path, for retry of indirect extents to work we need to
differentiate between the location in the btree the read was for, vs.
the location where we found the data. This patch adds that plumbing to
bch_read_bio.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 25 insertions, 21 deletions

diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index b402fc2e51d6..425502f7b1b8 100644
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -1627,8 +1627,8 @@ static void bch2_read_retry_nodecode(struct bch_fs *c, struct bch_read_bio *rbio
 	bch2_bkey_buf_init(&sk);
 	bch2_trans_init(&trans, c, 0, 0);
 
-	iter = bch2_trans_get_iter(&trans, BTREE_ID_extents,
-				   rbio->pos, BTREE_ITER_SLOTS);
+	iter = bch2_trans_get_iter(&trans, rbio->data_btree,
+				   rbio->read_pos, BTREE_ITER_SLOTS);
 retry:
 	rbio->bio.bi_status = 0;
 
@@ -1642,14 +1642,17 @@ retry:
 
 	if (!bch2_bkey_matches_ptr(c, k,
 				   rbio->pick.ptr,
-				   rbio->pos.offset -
+				   rbio->data_pos.offset -
 				   rbio->pick.crc.offset)) {
 		/* extent we wanted to read no longer exists: */
 		rbio->hole = true;
 		goto out;
 	}
 
-	ret = __bch2_read_extent(&trans, rbio, bvec_iter, k, 0, failed, flags);
+	ret = __bch2_read_extent(&trans, rbio, bvec_iter,
+				 rbio->read_pos,
+				 rbio->data_btree,
+				 k, 0, failed, flags);
 	if (ret == READ_RETRY)
 		goto retry;
 	if (ret)
@@ -1671,7 +1674,7 @@ static void bch2_rbio_retry(struct work_struct *work)
 	struct bch_fs *c	= rbio->c;
 	struct bvec_iter iter	= rbio->bvec_iter;
 	unsigned flags		= rbio->flags;
-	u64 inode		= rbio->pos.inode;
+	u64 inode		= rbio->read_pos.inode;
 	struct bch_io_failures failed = { .nr = 0 };
 
 	trace_read_retry(&rbio->bio);
@@ -1719,7 +1722,7 @@ static int __bch2_rbio_narrow_crcs(struct btree_trans *trans,
 				   struct bch_read_bio *rbio)
 {
 	struct bch_fs *c = rbio->c;
-	u64 data_offset = rbio->pos.offset - rbio->pick.crc.offset;
+	u64 data_offset = rbio->data_pos.offset - rbio->pick.crc.offset;
 	struct bch_extent_crc_unpacked new_crc;
 	struct btree_iter *iter = NULL;
 	struct bkey_i *new;
@@ -1729,7 +1732,7 @@ static int __bch2_rbio_narrow_crcs(struct btree_trans *trans,
 	if (crc_is_compressed(rbio->pick.crc))
 		return 0;
 
-	iter = bch2_trans_get_iter(trans, BTREE_ID_extents, rbio->pos,
+	iter = bch2_trans_get_iter(trans, rbio->data_btree, rbio->data_pos,
 				   BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 	k = bch2_btree_iter_peek_slot(iter);
 	if ((ret = bkey_err(k)))
@@ -1862,14 +1865,14 @@ csum_err:
 		return;
 	}
 
-	bch2_dev_inum_io_error(ca, rbio->pos.inode, (u64) rbio->bvec_iter.bi_sector,
+	bch2_dev_inum_io_error(ca, rbio->read_pos.inode, (u64) rbio->bvec_iter.bi_sector,
 		"data checksum error: expected %0llx:%0llx got %0llx:%0llx (type %u)",
 		rbio->pick.crc.csum.hi, rbio->pick.crc.csum.lo,
 		csum.hi, csum.lo, crc.csum_type);
 	bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
 	return;
 decompression_err:
-	bch_err_inum_ratelimited(c, rbio->pos.inode,
+	bch_err_inum_ratelimited(c, rbio->read_pos.inode,
 				 "decompression error");
 	bch2_rbio_error(rbio, READ_ERR, BLK_STS_IOERR);
 	return;
@@ -1892,13 +1895,9 @@ static void bch2_read_endio(struct bio *bio)
 	if (!rbio->split)
 		rbio->bio.bi_end_io = rbio->end_io;
 
-	/*
-	 * XXX: rbio->pos is not what we want here when reading from indirect
-	 * extents
-	 */
 	if (bch2_dev_inum_io_err_on(bio->bi_status, ca,
-				    rbio->pos.inode,
-				    rbio->pos.offset,
+				    rbio->read_pos.inode,
+				    rbio->read_pos.offset,
 				    "data read error: %s",
 			       bch2_blk_status_to_str(bio->bi_status))) {
 		bch2_rbio_error(rbio, READ_RETRY_AVOID, bio->bi_status);
@@ -1963,7 +1962,8 @@ err:
 }
 
 int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
-		       struct bvec_iter iter, struct bkey_s_c k,
+		       struct bvec_iter iter, struct bpos read_pos,
+		       enum btree_id data_btree, struct bkey_s_c k,
 		       unsigned offset_into_extent,
 		       struct bch_io_failures *failed, unsigned flags)
 {
@@ -1973,7 +1973,7 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 	struct bch_dev *ca;
 	struct promote_op *promote = NULL;
 	bool bounce = false, read_full = false, narrow_crcs = false;
-	struct bpos pos = bkey_start_pos(k.k);
+	struct bpos data_pos = bkey_start_pos(k.k);
 	int pick_ret;
 
 	if (bkey_extent_is_inline_data(k.k)) {
@@ -2049,7 +2049,7 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 			 pick.crc.offset ||
 			 offset_into_extent));
 
-		pos.offset += offset_into_extent;
+		data_pos.offset += offset_into_extent;
 		pick.ptr.offset += pick.crc.offset +
 			offset_into_extent;
 		offset_into_extent		= 0;
@@ -2123,7 +2123,9 @@ get_bio:
 	/* XXX: only initialize this if needed */
 	rbio->devs_have		= bch2_bkey_devs(k);
 	rbio->pick		= pick;
-	rbio->pos		= pos;
+	rbio->read_pos		= read_pos;
+	rbio->data_btree	= data_btree;
+	rbio->data_pos		= data_pos;
 	rbio->version		= k.k->version;
 	rbio->promote		= promote;
 	INIT_WORK(&rbio->work, NULL);
@@ -2249,6 +2251,7 @@ retry:
 				   BTREE_ITER_SLOTS);
 	while (1) {
 		unsigned bytes, sectors, offset_into_extent;
+		enum btree_id data_btree = BTREE_ID_extents;
 
 		bch2_btree_iter_set_pos(iter,
 				POS(inode, bvec_iter.bi_sector));
@@ -2264,7 +2267,7 @@ retry:
 
 		bch2_bkey_buf_reassemble(&sk, c, k);
 
-		ret = bch2_read_indirect_extent(&trans,
+		ret = bch2_read_indirect_extent(&trans, &data_btree,
 					&offset_into_extent, &sk);
 		if (ret)
 			goto err;
@@ -2289,7 +2292,8 @@ retry:
 		if (bvec_iter.bi_size == bytes)
 			flags |= BCH_READ_LAST_FRAGMENT;
 
-		ret = __bch2_read_extent(&trans, rbio, bvec_iter, k,
+		ret = __bch2_read_extent(&trans, rbio, bvec_iter, iter->pos,
+					 data_btree, k,
 					 offset_into_extent, failed, flags);
 		switch (ret) {
 		case READ_RETRY: