[PATCH 21/22] dm-verity-fec: log target_block instead of index_in_region

[Eric Biggers <ebiggers@kernel.org>]

The log message for a FEC error or correction includes the data device
name and index_in_region as the context.  Although the result of FEC
(for a particular dm-verity instance) is expected to be the same for a
given index_in_region, index_in_region does not uniquely identify the
actual target block that is being corrected.  Since that value
(target_block) is likely more useful, log it instead.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 drivers/md/dm-verity-fec.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
index 59ff3d58f49df..fbe01f809aca3 100644
--- a/drivers/md/dm-verity-fec.c
+++ b/drivers/md/dm-verity-fec.c
@@ -47,12 +47,13 @@ static inline u8 *fec_buffer_rs_message(struct dm_verity *v,
 /*
  * Decode all RS codewords whose message bytes were loaded into fio->bufs.  Copy
  * the corrected bytes into fio->output starting from out_pos.
  */
 static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
-			   struct dm_verity_fec_io *fio, u64 index_in_region,
-			   int target_region, unsigned int out_pos, int neras)
+			   struct dm_verity_fec_io *fio, u64 target_block,
+			   unsigned int target_region, u64 index_in_region,
+			   unsigned int out_pos, int neras)
 {
 	int r = 0, corrected = 0, res;
 	struct dm_buffer *buf;
 	unsigned int n, i, j, parity_pos, to_copy;
 	uint16_t par_buf[DM_VERITY_FEC_MAX_ROOTS];
@@ -73,11 +74,11 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
 	parity_block >>= v->data_dev_block_bits;
 	par = dm_bufio_read_with_ioprio(v->fec->bufio, parity_block, &buf,
 					bio->bi_ioprio);
 	if (IS_ERR(par)) {
 		DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
-		      v->data_dev->name, index_in_region, parity_block,
+		      v->data_dev->name, target_block, parity_block,
 		      PTR_ERR(par));
 		return PTR_ERR(par);
 	}
 
 	/*
@@ -103,11 +104,11 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
 			par = dm_bufio_read_with_ioprio(v->fec->bufio,
 							parity_block, &buf,
 							bio->bi_ioprio);
 			if (IS_ERR(par)) {
 				DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
-				      v->data_dev->name, index_in_region,
+				      v->data_dev->name, target_block,
 				      parity_block, PTR_ERR(par));
 				return PTR_ERR(par);
 			}
 			for (; j < v->fec->roots; j++)
 				par_buf[j] = par[parity_pos++];
@@ -129,14 +130,14 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
 done:
 	dm_bufio_release(buf);
 
 	if (r < 0 && neras)
 		DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",
-			    v->data_dev->name, index_in_region, r);
+			    v->data_dev->name, target_block, r);
 	else if (r == 0 && corrected > 0)
 		DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",
-			     v->data_dev->name, index_in_region, corrected);
+			     v->data_dev->name, target_block, corrected);
 
 	return r;
 }
 
 /*
@@ -155,11 +156,12 @@ static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io,
 /*
  * Read data blocks that are part of the RS block and deinterleave as much as
  * fits into buffers. Check for erasure locations if @neras is non-NULL.
  */
 static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
-			 u64 index_in_region, unsigned int out_pos, int *neras)
+			 u64 target_block, u64 index_in_region,
+			 unsigned int out_pos, int *neras)
 {
 	bool is_zero;
 	int i, j;
 	struct dm_buffer *buf;
 	struct dm_bufio_client *bufio;
@@ -199,11 +201,11 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
 		}
 
 		bbuf = dm_bufio_read_with_ioprio(bufio, block, &buf, bio->bi_ioprio);
 		if (IS_ERR(bbuf)) {
 			DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",
-				     v->data_dev->name, index_in_region, block,
+				     v->data_dev->name, target_block, block,
 				     PTR_ERR(bbuf));
 
 			/* assume the block is corrupted */
 			if (neras && *neras <= v->fec->roots)
 				fio->erasures[(*neras)++] = i;
@@ -324,17 +326,17 @@ static int fec_decode(struct dm_verity *v, struct dm_verity_io *io,
 		return -EIO;
 
 	for (out_pos = 0; out_pos < v->fec->block_size;) {
 		fec_init_bufs(v, fio);
 
-		r = fec_read_bufs(v, io, index_in_region, out_pos,
+		r = fec_read_bufs(v, io, target_block, index_in_region, out_pos,
 				  use_erasures ? &neras : NULL);
 		if (unlikely(r < 0))
 			return r;
 
-		r = fec_decode_bufs(v, io, fio, index_in_region, target_region,
-				    out_pos, neras);
+		r = fec_decode_bufs(v, io, fio, target_block, target_region,
+				    index_in_region, out_pos, neras);
 		if (r < 0)
 			return r;
 
 		out_pos += fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS;
 	}
@@ -344,11 +346,11 @@ static int fec_decode(struct dm_verity *v, struct dm_verity_io *io,
 	if (unlikely(r < 0))
 		return r;
 
 	if (memcmp(io->tmp_digest, want_digest, v->digest_size)) {
 		DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)",
-			    v->data_dev->name, index_in_region, neras);
+			    v->data_dev->name, target_block, neras);
 		return -EILSEQ;
 	}
 
 	return 0;
 }
-- 
2.52.0