[SCSI] st: add MTWEOFI to write filemarks without flushing drive buffer (3e51d3c9) · Commits · 戴 / test

Documentation/scsi/st.txt

+14 −1

Original line number	Diff line number	Diff line
		@@ -2,7 +2,7 @@ This file contains brief information about the SCSI tape driver.
		The driver is currently maintained by Kai Mäkisara (email
		Kai.Makisara@kolumbus.fi)

		Last modified: Sun Feb 24 21:59:07 2008 by kai.makisara
		Last modified: Sun Aug 29 18:25:47 2010 by kai.makisara


		BASICS
		@@ -85,6 +85,17 @@ writing and the last operation has been a write. Two filemarks can be
		optionally written. In both cases end of data is signified by
		returning zero bytes for two consecutive reads.

		Writing filemarks without the immediate bit set in the SCSI command block acts
		as a synchronization point, i.e., all remaining data form the drive buffers is
		written to tape before the command returns. This makes sure that write errors
		are caught at that point, but this takes time. In some applications, several
		consecutive files must be written fast. The MTWEOFI operation can be used to
		write the filemarks without flushing the drive buffer. Writing filemark at
		close() is always flushing the drive buffers. However, if the previous
		operation is MTWEOFI, close() does not write a filemark. This can be used if
		the program wants to close/open the tape device between files and wants to
		skip waiting.

		If rewind, offline, bsf, or seek is done and previous tape operation was
		write, a filemark is written before moving tape.

		@@ -301,6 +312,8 @@ MTBSR Space backward over count records.
		MTFSS Space forward over count setmarks.
		MTBSS Space backward over count setmarks.
		MTWEOF Write count filemarks.
		MTWEOFI Write count filemarks with immediate bit set (i.e., does not
		wait until data is on tape)
		MTWSM Write count setmarks.
		MTREW Rewind tape.
		MTOFFL Set device off line (often rewind plus eject).

drivers/scsi/st.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -9,7 +9,7 @@
		Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
		Michael Schaefer, J"org Weule, and Eric Youngdale.

		Copyright 1992 - 2008 Kai Makisara
		Copyright 1992 - 2010 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 = "20081215";
		static const char *verstr = "20100829";

		#include <linux/module.h>

		@@ -2696,18 +2696,21 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
		}
		break;
		case MTWEOF:
		case MTWEOFI:
		case MTWSM:
		if (STp->write_prot)
		return (-EACCES);
		cmd[0] = WRITE_FILEMARKS;
		if (cmd_in == MTWSM)
		cmd[1] = 2;
		if (cmd_in == MTWEOFI)
		cmd[1] \|= 1;
		cmd[2] = (arg >> 16);
		cmd[3] = (arg >> 8);
		cmd[4] = arg;
		timeout = STp->device->request_queue->rq_timeout;
		DEBC(
		if (cmd_in == MTWEOF)
		if (cmd_in != MTWSM)
		printk(ST_DEB_MSG "%s: Writing %d filemarks.\n", name,
		cmd[2] * 65536 + cmd[3] * 256 + cmd[4]);
		else
		@@ -2883,8 +2886,8 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
		else if (chg_eof)
		STps->eof = ST_NOEOF;

		if (cmd_in == MTWEOF)
		STps->rw = ST_IDLE;
		if (cmd_in == MTWEOF \|\| cmd_in == MTWEOFI)
		STps->rw = ST_IDLE; /* prevent automatic WEOF at close */
		} else { /* SCSI command was not completely successful. Don't return
		from this block without releasing the SCSI command block! */
		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
		@@ -2901,7 +2904,7 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
		else
		undone = 0;

		if (cmd_in == MTWEOF &&
		if ((cmd_in == MTWEOF \|\| cmd_in == MTWEOFI) &&
		cmdstatp->have_sense &&
		(cmdstatp->flags & SENSE_EOM)) {
		if (cmdstatp->sense_hdr.sense_key == NO_SENSE \|\|

include/linux/mtio.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -63,6 +63,7 @@ struct mtop {
		#define MTCOMPRESSION 32/* control compression with SCSI mode page 15 */
		#define MTSETPART 33 /* Change the active tape partition */
		#define MTMKPART 34 /* Format the tape with one or two partitions */
		#define MTWEOFI 35 /* write an end-of-file record (mark) in immediate mode */

		/* structure for MTIOCGET - mag tape get status command */

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