[PATCH] st: Fix MTMKPART to work with newer drives

[PATCH] st: Fix MTMKPART to work with newer drives

[Kai Makisara]

[-- Attachment #1: Type: text/plain, Size: 9629 bytes --]

Change the MTMKPART operation of the MTIOCTOP ioctl so that it works also with
current drives (LTO-5/6, etc.). Send a separate FORMAT MEDIUM command if the
partition mode page indicates that this is required. Use LOAD to position the
tape at the beginning of tape.

The operation is extended so that if the argument is negative, its absolute
value specifies the size of partition 0, which is the physically first
partition of the tape.

Signed-off-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Tested-by: Shane M Seymour <shane.seymour@hpe.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
---
 Documentation/scsi/st.txt |   15 ++--
 drivers/scsi/st.c         |  122 ++++++++++++++++++++++++++++++++----
 2 files changed, 121 insertions(+), 16 deletions(-)

--- a/drivers/scsi/st.c	2015-12-21 18:54:05.068882001 +0200
+++ b/drivers/scsi/st.c	2016-02-09 20:57:52.614816514 +0200
@@ -9,7 +9,7 @@
    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
    Michael Schaefer, J"org Weule, and Eric Youngdale.
 
-   Copyright 1992 - 2010 Kai Makisara
+   Copyright 1992 - 2016 Kai Makisara
    email Kai.Makisara@kolumbus.fi
 
    Some small formal changes - aeb, 950809
@@ -17,7 +17,7 @@
    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  */
 
-static const char *verstr = "20101219";
+static const char *verstr = "20160209";
 
 #include <linux/module.h>
 
@@ -3296,7 +3296,10 @@ static int switch_partition(struct scsi_
 #define PP_OFF_RESERVED        7
 
 #define PP_BIT_IDP             0x20
+#define PP_BIT_FDP             0x80
 #define PP_MSK_PSUM_MB         0x10
+#define PP_MSK_PSUM_UNITS      0x18
+#define PP_MSK_POFM            0x04
 
 /* Get the number of partitions on the tape. As a side effect reads the
    mode page into the tape buffer. */
@@ -3322,6 +3325,29 @@ static int nbr_partitions(struct scsi_ta
 }
 
 
+static int format_medium(struct scsi_tape *STp, int format)
+{
+	int result = 0;
+	int timeout = STp->long_timeout;
+	unsigned char scmd[MAX_COMMAND_SIZE];
+	struct st_request *SRpnt;
+
+	memset(scmd, 0, MAX_COMMAND_SIZE);
+	scmd[0] = FORMAT_UNIT;
+	scmd[2] = format;
+	if (STp->immediate) {
+		scmd[1] |= 1;		/* Don't wait for completion */
+		timeout = STp->device->request_queue->rq_timeout;
+	}
+	DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
+	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
+			   timeout, MAX_RETRIES, 1);
+	if (!SRpnt)
+		result = STp->buffer->syscall_result;
+	return result;
+}
+
+
 /* Partition the tape into two partitions if size > 0 or one partition if
    size == 0.
 
@@ -3340,11 +3366,16 @@ static int nbr_partitions(struct scsi_ta
    and 10 when 1 partition is defined (information from Eric Lee Green). This is
    is acceptable also to some other old drives and enforced if the first partition
    size field is used for the first additional partition size.
+
+   For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
  */
 static int partition_tape(struct scsi_tape *STp, int size)
 {
 	int result;
+	int target_partition;
+	bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
 	int pgo, psd_cnt, psdo;
+	int psum = PP_MSK_PSUM_MB, units = 0;
 	unsigned char *bp;
 
 	result = read_mode_page(STp, PART_PAGE, 0);
@@ -3352,6 +3383,12 @@ static int partition_tape(struct scsi_ta
 		DEBC_printk(STp, "Can't read partition mode page.\n");
 		return result;
 	}
+	target_partition = 1;
+	if (size < 0) {
+		target_partition = 0;
+		size = -size;
+	}
+
 	/* The mode page is in the buffer. Let's modify it and write it. */
 	bp = (STp->buffer)->b_data;
 	pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
@@ -3359,9 +3396,52 @@ static int partition_tape(struct scsi_ta
 		    bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
 
 	psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
+
+	if (scsi3) {
+		needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
+		if (needs_format && size == 0) {
+			/* No need to write the mode page when clearing
+			 *  partitioning
+			 */
+			DEBC_printk(STp, "Formatting tape with one partition.\n");
+			result = format_medium(STp, 0);
+			goto out;
+		}
+		if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
+			psd_cnt = 2;
+		if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
+			/* Use units scaling for large partitions if the device
+			 * suggests it and no precision lost. Required for IBM
+			 * TS1140/50 drives that don't support MB units.
+			 */
+			if (size >= 1000 && (size % 1000) == 0) {
+				size /= 1000;
+				psum = PP_MSK_PSUM_UNITS;
+				units = 9; /* GB */
+			}
+		}
+		/* Try it anyway if too large to specify in MB */
+		if (psum == PP_MSK_PSUM_MB && size >= 65534) {
+			size /= 1000;
+			psum = PP_MSK_PSUM_UNITS;
+			units = 9;  /* GB */
+		}
+	}
+
+	if (size >= 65535 ||  /* Does not fit into two bytes */
+	    (target_partition == 0 && psd_cnt < 2)) {
+		result = -EINVAL;
+		goto out;
+	}
+
 	psdo = pgo + PART_PAGE_FIXED_LENGTH;
-	if (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS]) {
-		bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest of the tape */
+	/* The second condition is for HP DDS which use only one partition size
+	 * descriptor
+	 */
+	if (target_partition > 0 &&
+	    (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
+	     bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
+		bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
 		psdo += 2;
 	}
 	memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
@@ -3370,7 +3450,7 @@ static int partition_tape(struct scsi_ta
 		    psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
 		    bp[pgo + PP_OFF_NBR_ADD_PARTS]);
 
-	if (size <= 0) {
+	if (size == 0) {
 		bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
 		if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
@@ -3378,22 +3458,37 @@ static int partition_tape(struct scsi_ta
 	} else {
 		bp[psdo] = (size >> 8) & 0xff;
 		bp[psdo + 1] = size & 0xff;
+		if (target_partition == 0)
+			bp[psdo + 2] = bp[psdo + 3] = 0xff;
 		bp[pgo + 3] = 1;
 		if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
-		DEBC_printk(STp, "Formatting tape with two partitions "
-			    "(1 = %d MB).\n", size);
+		DEBC_printk(STp,
+			    "Formatting tape with two partitions (%i = %d MB).\n",
+			    target_partition, units > 0 ? size * 1000 : size);
 	}
 	bp[pgo + PP_OFF_PART_UNITS] = 0;
 	bp[pgo + PP_OFF_RESERVED] = 0;
-	bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | PP_MSK_PSUM_MB;
+	if (size != 1 || units != 0) {
+		bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
+			(bp[pgo + PP_OFF_FLAGS] & 0x07);
+		bp[pgo + PP_OFF_PART_UNITS] = units;
+	} else
+		bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
+			(bp[pgo + PP_OFF_FLAGS] & 0x1f);
+	bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
 
 	result = write_mode_page(STp, PART_PAGE, 1);
+
+	if (!result && needs_format)
+		result = format_medium(STp, 1);
+
 	if (result) {
 		st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
 		result = (-EIO);
 	}
 
+out:
 	return result;
 }
 \f
@@ -3570,8 +3665,13 @@ static long st_ioctl(struct file *file,
 				retval = (-EINVAL);
 				goto out;
 			}
-			if ((i = st_int_ioctl(STp, MTREW, 0)) < 0 ||
-			    (i = partition_tape(STp, mtc.mt_count)) < 0) {
+			i = do_load_unload(STp, file, 1);
+			if (i < 0) {
+				retval = i;
+				goto out;
+			}
+			i = partition_tape(STp, mtc.mt_count);
+			if (i < 0) {
 				retval = i;
 				goto out;
 			}
@@ -3581,7 +3681,7 @@ static long st_ioctl(struct file *file,
 				STp->ps[i].last_block_valid = 0;
 			}
 			STp->partition = STp->new_partition = 0;
-			STp->nbr_partitions = 1;	/* Bad guess ?-) */
+			STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
 			STps->drv_block = STps->drv_file = 0;
 			retval = 0;
 			goto out;
--- a/Documentation/scsi/st.txt	2015-11-24 21:50:56.594913001 +0200
+++ b/Documentation/scsi/st.txt	2016-02-09 21:54:16.778547621 +0200
@@ -2,7 +2,7 @@ This file contains brief information abo
 The driver is currently maintained by Kai Mäkisara (email
 Kai.Makisara@kolumbus.fi)
 
-Last modified: Sun Aug 29 18:25:47 2010 by kai.makisara
+Last modified: Tue Feb  9 21:54:16 2016 by kai.makisara
 
 
 BASICS
@@ -408,10 +408,15 @@ MTSETPART Moves the tape to the partitio
 	specified by MTSEEK. MTSETPART is inactive unless
 	MT_ST_CAN_PARTITIONS set.
 MTMKPART Formats the tape with one partition (argument zero) or two
-	partitions (the argument gives in megabytes the size of
-	partition 1 that is physically the first partition of the
-	tape). The drive has to support partitions with size specified
-	by the initiator. Inactive unless MT_ST_CAN_PARTITIONS set.
+	partitions (argument non-zero). If the argument is positive,
+	it specifies the size of partition 1 in megabytes. For DDS
+	drives and several early drives this is the physically first
+	partition of the tape. If the argument is negative, its absolute
+	value specifies the size of partition 0 in megabytes. This is
+	the physically first partition of many later drives, like the
+	LTO drives from LTO-5 upwards. The drive has to support partitions
+	with size specified by the initiator. Inactive unless
+	MT_ST_CAN_PARTITIONS set.
 MTSETDRVBUFFER
 	Is used for several purposes. The command is obtained from count
         with mask MT_SET_OPTIONS, the low order bits are used as argument.

Re: [PATCH] st: Fix MTMKPART to work with newer drives

[Martin K. Petersen]

>>>>> "Kai" == Kai Makisara <Kai.Makisara@kolumbus.fi> writes:

Kai> Change the MTMKPART operation of the MTIOCTOP ioctl so that it
Kai> works also with current drives (LTO-5/6, etc.). Send a separate
Kai> FORMAT MEDIUM command if the partition mode page indicates that
Kai> this is required. Use LOAD to position the tape at the beginning of
Kai> tape.

Kai> The operation is extended so that if the argument is negative, its
Kai> absolute value specifies the size of partition 0, which is the
Kai> physically first partition of the tape.

Applied to 4.6/scsi-queue.

-- 
Martin K. Petersen	Oracle Linux Engineering