Add BUF_TRACKING and FULL_BUF_TRACKING buffer debugging

Upstream the BUF_TRACKING and FULL_BUF_TRACKING buffer debugging code.
This can be handy in tracking down what code touched hung bios and bufs
last. The full history is especially useful, but adds enough bloat that
it shouldn't be enabled in release builds.

Function names (or arbitrary string constants) are tracked in a
fixed-size ring in bufs. Bios gain a pointer to the upper buf for
tracking. SCSI CCBs gain a pointer to the upper bio for tracking.

Reviewed by:	markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D8366

4 files changed, 43 insertions, 0 deletions

diff --git a/sys/cam/cam_ccb.h b/sys/cam/cam_ccb.h
index 9ec266e84cc1..b638ab1dba9f 100644
--- a/sys/cam/cam_ccb.h
+++ b/sys/cam/cam_ccb.h
@@ -744,6 +744,9 @@ struct ccb_scsiio {
 #define		CAM_TAG_ACTION_NONE	0x00
 	u_int	   tag_id;		/* tag id from initator (target mode) */
 	u_int	   init_id;		/* initiator id of who selected */
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+	struct bio *bio;		/* Associated bio */
+#endif
 };
 
 static __inline uint8_t *
@@ -1335,6 +1338,9 @@ cam_fill_csio(struct ccb_scsiio *csio, u_int32_t retries,
 	csio->sense_len = sense_len;
 	csio->cdb_len = cdb_len;
 	csio->tag_action = tag_action;
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+	csio->bio = NULL;
+#endif
 }
 
 static __inline void
diff --git a/sys/cam/cam_periph.c b/sys/cam/cam_periph.c
index 942a6c30376f..ae4134504b9c 100644
--- a/sys/cam/cam_periph.c
+++ b/sys/cam/cam_periph.c
@@ -1427,6 +1427,11 @@ camperiphscsisenseerror(union ccb *ccb, union ccb **orig,
 	union ccb *orig_ccb = ccb;
 	int error, recoveryccb;
 
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+	if (ccb->ccb_h.func_code == XPT_SCSI_IO && ccb->csio.bio != NULL)
+		biotrack(ccb->csio.bio, __func__);
+#endif
+
 	periph = xpt_path_periph(ccb->ccb_h.path);
 	recoveryccb = (ccb->ccb_h.cbfcnp == camperiphdone);
 	if ((periph->flags & CAM_PERIPH_RECOVERY_INPROG) && !recoveryccb) {
diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
index cfca7807c781..34018052ed60 100644
--- a/sys/cam/cam_xpt.c
+++ b/sys/cam/cam_xpt.c
@@ -31,6 +31,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/bio.h>
 #include <sys/bus.h>
 #include <sys/systm.h>
 #include <sys/types.h>
@@ -4471,6 +4472,12 @@ xpt_done(union ccb *done_ccb)
 	struct cam_doneq *queue;
 	int	run, hash;
 
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+	if (done_ccb->ccb_h.func_code == XPT_SCSI_IO &&
+	    done_ccb->csio.bio != NULL)
+		biotrack(done_ccb->csio.bio, __func__);
+#endif
+
 	CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE,
 	    ("xpt_done: func= %#x %s status %#x\n",
 		done_ccb->ccb_h.func_code,
@@ -5189,6 +5196,16 @@ xpt_done_process(struct ccb_hdr *ccb_h)
 	struct cam_devq *devq;
 	struct mtx *mtx = NULL;
 
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+	struct ccb_scsiio *csio;
+
+	if (ccb_h->func_code == XPT_SCSI_IO) {
+		csio = &((union ccb *)ccb_h)->csio;
+		if (csio->bio != NULL)
+			biotrack(csio->bio, __func__);
+	}
+#endif
+
 	if (ccb_h->flags & CAM_HIGH_POWER) {
 		struct highpowerlist	*hphead;
 		struct cam_ed		*device;
diff --git a/sys/cam/scsi/scsi_da.c b/sys/cam/scsi/scsi_da.c
index 977ac8d6252b..16d8ef7b07ca 100644
--- a/sys/cam/scsi/scsi_da.c
+++ b/sys/cam/scsi/scsi_da.c
@@ -2949,6 +2949,8 @@ more:
 			void *data_ptr;
 			int rw_op;
 
+			biotrack(bp, __func__);
+
 			if (bp->bio_cmd == BIO_WRITE) {
 				softc->flags |= DA_FLAG_DIRTY;
 				rw_op = SCSI_RW_WRITE;
@@ -2976,6 +2978,9 @@ more:
 					/*dxfer_len*/ bp->bio_bcount,
 					/*sense_len*/SSD_FULL_SIZE,
 					da_default_timeout * 1000);
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+			start_ccb->csio.bio = bp;
+#endif
 			break;
 		}
 		case BIO_FLUSH:
@@ -4008,6 +4013,10 @@ dadone(struct cam_periph *periph, union ccb *done_ccb)
 	CAM_DEBUG(periph->path, CAM_DEBUG_TRACE, ("dadone\n"));
 
 	csio = &done_ccb->csio;
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+	if (csio->bio != NULL)
+		biotrack(csio->bio, __func__);
+#endif
 	state = csio->ccb_h.ccb_state & DA_CCB_TYPE_MASK;
 	switch (state) {
 	case DA_CCB_BUFFER_IO:
@@ -4106,6 +4115,7 @@ dadone(struct cam_periph *periph, union ccb *done_ccb)
 			}
 		}
 
+		biotrack(bp, __func__);
 		LIST_REMOVE(&done_ccb->ccb_h, periph_links.le);
 		if (LIST_EMPTY(&softc->pending_ccbs))
 			softc->flags |= DA_FLAG_WAS_OTAG;
@@ -5219,6 +5229,11 @@ daerror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
 	struct cam_periph *periph;
 	int error, error_code, sense_key, asc, ascq;
 
+#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
+	if (ccb->csio.bio != NULL)
+		biotrack(ccb->csio.bio, __func__);
+#endif
+
 	periph = xpt_path_periph(ccb->ccb_h.path);
 	softc = (struct da_softc *)periph->softc;