patch-2.1.66 linux/drivers/char/ftape/lowlevel/ftape-write.c

• Lines: 338
• Date: Tue Nov 25 14:45:27 1997
• Orig file: v2.1.65/linux/drivers/char/ftape/lowlevel/ftape-write.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.65/linux/drivers/char/ftape/lowlevel/ftape-write.c linux/drivers/char/ftape/lowlevel/ftape-write.c
@@ -0,0 +1,337 @@
+/*
+ *      Copyright (C) 1993-1995 Bas Laarhoven,
+ *                (C) 1996-1997 Claus-Justus Heine.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; see the file COPYING.  If not, write to
+ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ *
+ * $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-write.c,v $
+ * $Revision: 1.3.4.1 $
+ * $Date: 1997/11/14 18:07:04 $
+ *
+ *      This file contains the writing code
+ *      for the QIC-117 floppy-tape driver for Linux.
+ */
+
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <asm/segment.h>
+
+#include <linux/ftape.h>
+#include <linux/qic117.h>
+#include "../lowlevel/ftape-tracing.h"
+#include "../lowlevel/ftape-write.h"
+#include "../lowlevel/ftape-read.h"
+#include "../lowlevel/ftape-io.h"
+#include "../lowlevel/ftape-ctl.h"
+#include "../lowlevel/ftape-rw.h"
+#include "../lowlevel/ftape-ecc.h"
+#include "../lowlevel/ftape-bsm.h"
+#include "../lowlevel/fdc-isr.h"
+
+/*      Global vars.
+ */
+
+/*      Local vars.
+ */
+static int last_write_failed = 0;
+
+void ftape_zap_write_buffers(void)
+{
+	int i;
+
+	for (i = 0; i < ft_nr_buffers; ++i) {
+		ft_buffer[i]->status = done;
+	}
+	ftape_reset_buffer();
+}
+
+static int copy_and_gen_ecc(void *destination, 
+			    const void *source,
+			    const SectorMap bad_sector_map)
+{
+	int result;
+	struct memory_segment mseg;
+	int bads = count_ones(bad_sector_map);
+	TRACE_FUN(ft_t_any);
+
+	if (bads > 0) {
+		TRACE(ft_t_noise, "bad sectors in map: %d", bads);
+	}
+	if (bads + 3 >= FT_SECTORS_PER_SEGMENT) {
+		TRACE(ft_t_noise, "empty segment");
+		mseg.blocks = 0; /* skip entire segment */
+		result = 0;      /* nothing written */
+	} else {
+		mseg.blocks = FT_SECTORS_PER_SEGMENT - bads;
+		mseg.data = destination;
+		memcpy(mseg.data, source, (mseg.blocks - 3) * FT_SECTOR_SIZE);
+		result = ftape_ecc_set_segment_parity(&mseg);
+		if (result < 0) {
+			TRACE(ft_t_err, "ecc_set_segment_parity failed");
+		} else {
+			result = (mseg.blocks - 3) * FT_SECTOR_SIZE;
+		}
+	}
+	TRACE_EXIT result;
+}
+
+
+int ftape_start_writing(const ft_write_mode_t mode)
+{
+	buffer_struct *head = ftape_get_buffer(ft_queue_head);
+	int segment_id = head->segment_id;
+	int result;
+	buffer_state_enum wanted_state = (mode == FT_WR_DELETE
+					  ? deleting
+					  : writing);
+	TRACE_FUN(ft_t_flow);
+
+	if ((ft_driver_state != wanted_state) || head->status != waiting) {
+		TRACE_EXIT 0;
+	}
+	ftape_setup_new_segment(head, segment_id, 1);
+	if (mode == FT_WR_SINGLE) {
+		/* stop tape instead of pause */
+		head->next_segment = 0;
+	}
+	ftape_calc_next_cluster(head); /* prepare */
+	head->status = ft_driver_state; /* either writing or deleting */
+	if (ft_runner_status == idle) {
+		TRACE(ft_t_noise,
+		      "starting runner for segment %d", segment_id);
+		TRACE_CATCH(ftape_start_tape(segment_id,head->sector_offset),);
+	} else {
+		TRACE(ft_t_noise, "runner not idle, not starting tape");
+	}
+	/* go */
+	result = fdc_setup_read_write(head, (mode == FT_WR_DELETE
+					     ? FDC_WRITE_DELETED : FDC_WRITE));
+	ftape_set_state(wanted_state); /* should not be necessary */
+	TRACE_EXIT result;
+}
+
+/*  Wait until all data is actually written to tape.
+ *  
+ *  There is a problem: when the tape runs into logical EOT, then this
+ *  failes. We need to restart the runner in this case.
+ */
+int ftape_loop_until_writes_done(void)
+{
+	buffer_struct *head;
+	TRACE_FUN(ft_t_flow);
+
+	while ((ft_driver_state == writing || ft_driver_state == deleting) && 
+	       ftape_get_buffer(ft_queue_head)->status != done) {
+		/* set the runner status to idle if at lEOT */
+		TRACE_CATCH(ftape_handle_logical_eot(),	last_write_failed = 1);
+		/* restart the tape if necessary */
+		if (ft_runner_status == idle) {
+			TRACE(ft_t_noise, "runner is idle, restarting");
+			if (ft_driver_state == deleting) {
+				TRACE_CATCH(ftape_start_writing(FT_WR_DELETE),
+					    last_write_failed = 1);
+			} else {
+				TRACE_CATCH(ftape_start_writing(FT_WR_MULTI),
+					    last_write_failed = 1);
+			}
+		}
+		TRACE(ft_t_noise, "tail: %d, head: %d", 
+		      ftape_buffer_id(ft_queue_tail),
+		      ftape_buffer_id(ft_queue_head));
+		TRACE_CATCH(fdc_interrupt_wait(5 * FT_SECOND),
+			    last_write_failed = 1);
+		head = ftape_get_buffer(ft_queue_head);
+		if (head->status == error) {
+			/* Allow escape from loop when signaled !
+			 */
+			FT_SIGNAL_EXIT(_DONT_BLOCK);
+			if (head->hard_error_map != 0) {
+				/*  Implement hard write error recovery here
+				 */
+			}
+			/* retry this one */
+			head->status = waiting;
+			if (ft_runner_status == aborting) {
+				ftape_dumb_stop();
+			}
+			if (ft_runner_status != idle) {
+				TRACE_ABORT(-EIO, ft_t_err,
+					    "unexpected state: "
+					    "ft_runner_status != idle");
+			}
+			ftape_start_writing(ft_driver_state == deleting
+					    ? FT_WR_MULTI : FT_WR_DELETE);
+		}
+		TRACE(ft_t_noise, "looping until writes done");
+	}
+	ftape_set_state(idle);
+	TRACE_EXIT 0;
+}
+
+/*      Write given segment from buffer at address to tape.
+ */
+static int write_segment(const int segment_id,
+			 const void *address, 
+			 const ft_write_mode_t write_mode)
+{
+	int bytes_written = 0;
+	buffer_struct *tail;
+	buffer_state_enum wanted_state = (write_mode == FT_WR_DELETE
+					  ? deleting : writing);
+	TRACE_FUN(ft_t_flow);
+
+	TRACE(ft_t_noise, "segment_id = %d", segment_id);
+	if (ft_driver_state != wanted_state) {
+		if (ft_driver_state == deleting ||
+		    wanted_state == deleting) {
+			TRACE_CATCH(ftape_loop_until_writes_done(),);
+		}
+		TRACE(ft_t_noise, "calling ftape_abort_operation");
+		TRACE_CATCH(ftape_abort_operation(),);
+		ftape_zap_write_buffers();
+		ftape_set_state(wanted_state);
+	}
+	/*    if all buffers full we'll have to wait...
+	 */
+	ftape_wait_segment(wanted_state);
+	tail = ftape_get_buffer(ft_queue_tail);
+	switch(tail->status) {
+	case done:
+		ft_history.defects += count_ones(tail->hard_error_map);
+		break;
+	case waiting:
+		/* this could happen with multiple EMPTY_SEGMENTs, but
+		 * shouldn't happen any more as we re-start the runner even
+		 * with an empty segment.
+		 */
+		bytes_written = -EAGAIN;
+		break;
+	case error:
+		/*  setup for a retry
+		 */
+		tail->status = waiting;
+		bytes_written = -EAGAIN; /* force retry */
+		if (tail->hard_error_map != 0) {
+			TRACE(ft_t_warn, 
+			      "warning: %d hard error(s) in written segment",
+			      count_ones(tail->hard_error_map));
+			TRACE(ft_t_noise, "hard_error_map = 0x%08lx", 
+			      (long)tail->hard_error_map);
+			/*  Implement hard write error recovery here
+			 */
+		}
+		break;
+	default:
+		TRACE_ABORT(-EIO, ft_t_err,
+			    "wait for empty segment failed, tail status: %d",
+			    tail->status);
+	}
+	/*    should runner stop ?
+	 */
+	if (ft_runner_status == aborting) {
+		buffer_struct *head = ftape_get_buffer(ft_queue_head);
+		if (head->status == wanted_state) {
+			head->status = done; /* ???? */
+		}
+		/*  don't call abort_operation(), we don't want to zap
+		 *  the dma buffers
+		 */
+		TRACE_CATCH(ftape_dumb_stop(),);
+	} else {
+		/*  If just passed last segment on tape: wait for BOT
+		 *  or EOT mark. Sets ft_runner_status to idle if at lEOT
+		 *  and successful 
+		 */
+		TRACE_CATCH(ftape_handle_logical_eot(),);
+	}
+	if (tail->status == done) {
+		/* now at least one buffer is empty, fill it with our
+		 * data.  skip bad sectors and generate ecc.
+		 * copy_and_gen_ecc return nr of bytes written, range
+		 * 0..29 Kb inclusive!  
+		 *
+		 * Empty segments are handled inside coyp_and_gen_ecc()
+		 */
+		if (write_mode != FT_WR_DELETE) {
+			TRACE_CATCH(bytes_written = copy_and_gen_ecc(
+				tail->address, address,
+				ftape_get_bad_sector_entry(segment_id)),);
+		}
+		tail->segment_id = segment_id;
+		tail->status = waiting;
+		tail = ftape_next_buffer(ft_queue_tail);
+	}
+	/*  Start tape only if all buffers full or flush mode.
+	 *  This will give higher probability of streaming.
+	 */
+	if (ft_runner_status != running && 
+	    ((tail->status == waiting &&
+	      ftape_get_buffer(ft_queue_head) == tail) ||
+	     write_mode != FT_WR_ASYNC)) {
+		TRACE_CATCH(ftape_start_writing(write_mode),);
+	}
+	TRACE_EXIT bytes_written;
+}
+
+/*  Write as much as fits from buffer to the given segment on tape
+ *  and handle retries.
+ *  Return the number of bytes written (>= 0), or:
+ *      -EIO          write failed
+ *      -EINTR        interrupted by signal
+ *      -ENOSPC       device full
+ */
+int ftape_write_segment(const int segment_id,
+			const void *buffer, 
+			const ft_write_mode_t flush)
+{
+	int retry = 0;
+	int result;
+	TRACE_FUN(ft_t_flow);
+
+	ft_history.used |= 2;
+	if (segment_id >= ft_tracks_per_tape*ft_segments_per_track) {
+		/* tape full */
+		TRACE_ABORT(-ENOSPC, ft_t_err,
+			    "invalid segment id: %d (max %d)", 
+			    segment_id, 
+			    ft_tracks_per_tape * ft_segments_per_track -1);
+	}
+	for (;;) {
+		if ((result = write_segment(segment_id, buffer, flush)) >= 0) {
+			if (result == 0) { /* empty segment */
+				TRACE(ft_t_noise,
+				      "empty segment, nothing written");
+			}
+			TRACE_EXIT result;
+		}
+		if (result == -EAGAIN) {
+			if (++retry > 100) { /* give up */
+				TRACE_ABORT(-EIO, ft_t_err,
+				      "write failed, >100 retries in segment");
+			}
+			TRACE(ft_t_warn, "write error, retry %d (%d)",
+			      retry,
+			      ftape_get_buffer(ft_queue_tail)->segment_id);
+		} else {
+			TRACE_ABORT(result, ft_t_err,
+				    "write_segment failed, error: %d", result);
+		}
+		/* Allow escape from loop when signaled !
+		 */
+		FT_SIGNAL_EXIT(_DONT_BLOCK);
+	}
+}