libceph: dump osdmap and enhance output on decode errors

Dump osdmap in hex on both full and incremental decode errors, to make
it easier to match the contents with error offset.  dout() map epoch
and max_osd value on success.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

net/ceph/osdmap.c

@@ -690,6 +690,7 @@ struct ceph_osdmap *osdmap_decode(void **p, void *end)
 	u16 version;
 	u32 len, max, i;
 	int err = -EINVAL;
+	u32 epoch = 0;
 	void *start = *p;
 	struct ceph_pg_pool_info *pi;
 
@@ -714,7 +715,7 @@ struct ceph_osdmap *osdmap_decode(void **p, void *end)
 
 	ceph_decode_need(p, end, 2*sizeof(u64)+6*sizeof(u32), bad);
 	ceph_decode_copy(p, &map->fsid, sizeof(map->fsid));
-	map->epoch = ceph_decode_32(p);
+	epoch = map->epoch = ceph_decode_32(p);
 	ceph_decode_copy(p, &map->created, sizeof(map->created));
 	ceph_decode_copy(p, &map->modified, sizeof(map->modified));
 
@@ -814,14 +815,18 @@ struct ceph_osdmap *osdmap_decode(void **p, void *end)
 		goto bad;
 	}
 
-	/* ignore the rest of the map */
+	/* ignore the rest */
 	*p = end;
 
-	dout("osdmap_decode done %p %p\n", *p, end);
+	dout("full osdmap epoch %d max_osd %d\n", map->epoch, map->max_osd);
 	return map;
 
 bad:
-	dout("osdmap_decode fail err %d\n", err);
+	pr_err("corrupt full osdmap (%d) epoch %d off %d (%p of %p-%p)\n",
+	       err, epoch, (int)(*p - start), *p, start, end);
+	print_hex_dump(KERN_DEBUG, "osdmap: ",
+		       DUMP_PREFIX_OFFSET, 16, 1,
+		       start, end - start, true);
 	ceph_osdmap_destroy(map);
 	return ERR_PTR(err);
 }
@@ -845,6 +850,8 @@ struct ceph_osdmap *osdmap_apply_incremental(void **p, void *end,
 	int err = -EINVAL;
 	u16 version;
 
+	dout("%s %p to %p len %d\n", __func__, *p, end, (int)(end - *p));
+
 	ceph_decode_16_safe(p, end, version, bad);
 	if (version != 6) {
 		pr_warning("got unknown v %d != 6 of inc osdmap\n", version);
@@ -1032,11 +1039,13 @@ struct ceph_osdmap *osdmap_apply_incremental(void **p, void *end,
 
 	/* ignore the rest */
 	*p = end;
+
+	dout("inc osdmap epoch %d max_osd %d\n", map->epoch, map->max_osd);
 	return map;
 
 bad:
-	pr_err("corrupt inc osdmap epoch %d off %d (%p of %p-%p)\n",
-	       epoch, (int)(*p - start), *p, start, end);
+	pr_err("corrupt inc osdmap (%d) epoch %d off %d (%p of %p-%p)\n",
+	       err, epoch, (int)(*p - start), *p, start, end);
 	print_hex_dump(KERN_DEBUG, "osdmap: ",
 		       DUMP_PREFIX_OFFSET, 16, 1,
 		       start, end - start, true);