Synchronize device cache on close only if there were some write operations.

While these operations are not really needed otherwise, at least for SCSI
they may cause extra errors if some other initiator holds write exclusive
reservation on the LUN (SYNCHRONIZE CACHE handled as "write" operation).

2 files changed, 24 insertions, 10 deletions

diff --git a/sys/cam/ata/ata_da.c b/sys/cam/ata/ata_da.c
index 6e9c462..3dac0ac 100644
--- a/sys/cam/ata/ata_da.c
+++ b/sys/cam/ata/ata_da.c
@@ -86,7 +86,8 @@ typedef enum {
 	ADA_FLAG_SCTX_INIT	= 0x0200,
 	ADA_FLAG_CAN_CFA        = 0x0400,
 	ADA_FLAG_CAN_POWERMGT   = 0x0800,
-	ADA_FLAG_CAN_DMA48	= 0x1000
+	ADA_FLAG_CAN_DMA48	= 0x1000,
+	ADA_FLAG_DIRTY		= 0x2000
 } ada_flags;
 
 typedef enum {
@@ -602,6 +603,7 @@ adaclose(struct disk *dp)
 	struct	cam_periph *periph;
 	struct	ada_softc *softc;
 	union ccb *ccb;
+	int error;
 
 	periph = (struct cam_periph *)dp->d_drv1;
 	cam_periph_lock(periph);
@@ -617,7 +619,8 @@ adaclose(struct disk *dp)
 	    ("adaclose\n"));
 
 	/* We only sync the cache if the drive is capable of it. */
-	if ((softc->flags & ADA_FLAG_CAN_FLUSHCACHE) != 0 &&
+	if ((softc->flags & ADA_FLAG_DIRTY) != 0 &&
+	    (softc->flags & ADA_FLAG_CAN_FLUSHCACHE) != 0 &&
 	    (periph->flags & CAM_PERIPH_INVALID) == 0) {
 
 		ccb = cam_periph_getccb(periph, CAM_PRIORITY_NORMAL);
@@ -634,11 +637,13 @@ adaclose(struct disk *dp)
 			ata_48bit_cmd(&ccb->ataio, ATA_FLUSHCACHE48, 0, 0, 0);
 		else
 			ata_28bit_cmd(&ccb->ataio, ATA_FLUSHCACHE, 0, 0, 0);
-		cam_periph_runccb(ccb, adaerror, /*cam_flags*/0,
+		error = cam_periph_runccb(ccb, adaerror, /*cam_flags*/0,
 		    /*sense_flags*/0, softc->disk->d_devstat);
 
-		if ((ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP)
+		if (error != 0)
 			xpt_print(periph->path, "Synchronize cache failed\n");
+		else
+			softc->flags &= ~ADA_FLAG_DIRTY;
 		xpt_release_ccb(ccb);
 	}
 
@@ -1479,8 +1484,10 @@ adastart(struct cam_periph *periph, union ccb *start_ccb)
 			tag_code = 1;
 		}
 		switch (bp->bio_cmd) {
-		case BIO_READ:
 		case BIO_WRITE:
+			softc->flags |= ADA_FLAG_DIRTY;
+			/* FALLTHROUGH */
+		case BIO_READ:
 		{
 			uint64_t lba = bp->bio_pblkno;
 			uint16_t count = bp->bio_bcount / softc->params.secsize;
diff --git a/sys/cam/scsi/scsi_da.c b/sys/cam/scsi/scsi_da.c
index ae80b65..8d0f35e 100644
--- a/sys/cam/scsi/scsi_da.c
+++ b/sys/cam/scsi/scsi_da.c
@@ -89,7 +89,8 @@ typedef enum {
 	DA_FLAG_OPEN		= 0x100,
 	DA_FLAG_SCTX_INIT	= 0x200,
 	DA_FLAG_CAN_RC16	= 0x400,
-	DA_FLAG_PROBED		= 0x800		
+	DA_FLAG_PROBED		= 0x800,
+	DA_FLAG_DIRTY		= 0x1000
 } da_flags;
 
 typedef enum {
@@ -1237,6 +1238,7 @@ daclose(struct disk *dp)
 {
 	struct	cam_periph *periph;
 	struct	da_softc *softc;
+	int error;
 
 	periph = (struct cam_periph *)dp->d_drv1;
 	cam_periph_lock(periph);
@@ -1251,8 +1253,9 @@ daclose(struct disk *dp)
 	CAM_DEBUG(periph->path, CAM_DEBUG_TRACE | CAM_DEBUG_PERIPH,
 	    ("daclose\n"));
 
-	if ((softc->quirks & DA_Q_NO_SYNC_CACHE) == 0
-	 && (softc->flags & DA_FLAG_PACK_INVALID) == 0) {
+	if ((softc->flags & DA_FLAG_DIRTY) != 0 &&
+	    (softc->quirks & DA_Q_NO_SYNC_CACHE) == 0 &&
+	    (softc->flags & DA_FLAG_PACK_INVALID) == 0) {
 		union	ccb *ccb;
 
 		ccb = cam_periph_getccb(periph, CAM_PRIORITY_NORMAL);
@@ -1266,9 +1269,11 @@ daclose(struct disk *dp)
 				       SSD_FULL_SIZE,
 				       5 * 60 * 1000);
 
-		cam_periph_runccb(ccb, daerror, /*cam_flags*/0,
+		error = cam_periph_runccb(ccb, daerror, /*cam_flags*/0,
 				  /*sense_flags*/SF_RETRY_UA | SF_QUIET_IR,
 				  softc->disk->d_devstat);
+		if (error == 0)
+			softc->flags &= ~DA_FLAG_DIRTY;
 		xpt_release_ccb(ccb);
 
 	}
@@ -2240,8 +2245,10 @@ skipstate:
 		}
 
 		switch (bp->bio_cmd) {
-		case BIO_READ:
 		case BIO_WRITE:
+			softc->flags |= DA_FLAG_DIRTY;
+			/* FALLTHROUGH */
+		case BIO_READ:
 			scsi_read_write(&start_ccb->csio,
 					/*retries*/da_retry_count,
 					/*cbfcnp*/dadone,