[PATCH] Adds check for rand_seed during verify phase.

[Juan Casse <jcasse@xxxxxxxxxxxx>]

Improve data integrity checking of header (meta) data.
verify_header() will now return an additional error:
"verify: bad header rand seed ..."
The addition of the check of rand_seed helps detect stale data from
previous fio runs.
This patch also disambiguates the different data mismatches by returning
different error codes from verify_header().

Signed-off-by: Juan Casse <jcasse@xxxxxxxxxxxx>
Reviewed-by: Grant Grundler <grundler@xxxxxxxxxxxx>
---
 verify.c | 45 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 36 insertions(+), 9 deletions(-)

diff --git a/verify.c b/verify.c
index 9e88d61..957613c 100644
--- a/verify.c
+++ b/verify.c
@@ -644,18 +644,17 @@ static int verify_header(struct io_u *io_u, struct verify_header *hdr)
 	uint32_t crc;
 
 	if (hdr->magic != FIO_HDR_MAGIC)
-		return 0;
-	if (hdr->len > io_u->buflen) {
-		log_err("fio: verify header exceeds buffer length (%u > %lu)\n", hdr->len, io_u->buflen);
-		return 0;
-	}
+		return 1;
+	if (hdr->len > io_u->buflen)
+		return 2;
+	if (hdr->rand_seed != io_u->rand_seed)
+		return 3;
 
 	crc = fio_crc32c(p, offsetof(struct verify_header, crc32));
 	if (crc == hdr->crc32)
-		return 1;
-
+		return 0;
 	log_err("fio: verify header crc %x, calculated %x\n", hdr->crc32, crc);
-	return 0;
+	return 4;
 }
 
 int verify_io_u(struct thread_data *td, struct io_u *io_u)
@@ -692,13 +691,41 @@ int verify_io_u(struct thread_data *td, struct io_u *io_u)
 			memswp(p, p + td->o.verify_offset, header_size);
 		hdr = p;
 
-		if (!verify_header(io_u, hdr)) {
+		ret = verify_header(io_u, hdr);
+		switch (ret) {
+		case 0:
+			break;
+		case 1:
 			log_err("verify: bad magic header %x, wanted %x at "
 				"file %s offset %llu, length %u\n",
 				hdr->magic, FIO_HDR_MAGIC,
 				io_u->file->file_name,
 				io_u->offset + hdr_num * hdr->len, hdr->len);
 			return EILSEQ;
+			break;
+		case 2:
+			log_err("fio: verify header exceeds buffer length (%u "
+				"> %lu)\n", hdr->len, io_u->buflen);
+			return EILSEQ;
+			break;
+		case 3:
+			log_err("verify: bad header rand_seed %"PRIu64
+				", wanted %"PRIu64" at file %s offset %llu, "
+				"length %u\n",
+				hdr->rand_seed, io_u->rand_seed,
+				io_u->file->file_name,
+				io_u->offset + hdr_num * hdr->len, hdr->len);
+			return EILSEQ;
+			break;
+		case 4:
+			return EILSEQ;
+			break;
+		default:
+			log_err("verify: unknown header error at file %s "
+			"offset %llu, length %u\n",
+			io_u->file->file_name,
+			io_u->offset + hdr_num * hdr->len, hdr->len);
+			return EILSEQ;
 		}
 
 		if (td->o.verify != VERIFY_NONE)
-- 
1.7.12.4

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