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

• Lines: 497
• Date: Tue Nov 25 14:45:28 1997
• Orig file: v2.1.65/linux/drivers/char/ftape/zftape/zftape-write.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.65/linux/drivers/char/ftape/zftape/zftape-write.c linux/drivers/char/ftape/zftape/zftape-write.c
@@ -0,0 +1,496 @@
+/*
+ *      Copyright (C) 1996, 1997 Claus 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/zftape/zftape-write.c,v $
+ * $Revision: 1.3 $
+ * $Date: 1997/11/06 00:50:29 $
+ *
+ *      This file contains the writing code
+ *      for the QIC-117 floppy-tape driver for Linux.
+ */
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#ifdef CONFIG_KERNELD
+#include <linux/kerneld.h>
+#endif
+
+#include <linux/zftape.h>
+
+#if LINUX_VERSION_CODE >= KERNEL_VER(2,1,6)
+#include <asm/uaccess.h>
+#else
+#include <asm/segment.h>
+#endif
+
+#include "../zftape/zftape-init.h"
+#include "../zftape/zftape-eof.h"
+#include "../zftape/zftape-ctl.h"
+#include "../zftape/zftape-write.h"
+#include "../zftape/zftape-read.h"
+#include "../zftape/zftape-rw.h"
+#include "../zftape/zftape-vtbl.h"
+
+/*      Global vars.
+ */
+
+/*      Local vars.
+ */
+static int last_write_failed = 0;
+static int need_flush = 0;
+
+void zft_prevent_flush(void)
+{
+	need_flush = 0;
+}
+
+static int zft_write_header_segments(__u8* buffer)
+{
+	int header_1_ok = 0;
+	int header_2_ok = 0;
+	unsigned int time_stamp;
+	TRACE_FUN(ft_t_noise);
+	
+	TRACE_CATCH(ftape_abort_operation(),);
+	ftape_seek_to_bot();    /* prevents extra rewind */
+	if (GET4(buffer, 0) != FT_HSEG_MAGIC) {
+		TRACE_ABORT(-EIO, ft_t_err,
+			    "wrong header signature found, aborting");
+	} 
+	/*   Be optimistic: */
+	PUT4(buffer, FT_SEG_CNT,
+	     zft_written_segments + GET4(buffer, FT_SEG_CNT) + 2);
+	if ((time_stamp = zft_get_time()) != 0) {
+		PUT4(buffer, FT_WR_DATE, time_stamp);
+		if (zft_label_changed) {
+			PUT4(buffer, FT_LABEL_DATE, time_stamp);
+		}
+	}
+	TRACE(ft_t_noise,
+	      "writing first header segment %d", ft_header_segment_1);
+	header_1_ok = zft_verify_write_segments(ft_header_segment_1, 
+						buffer, FT_SEGMENT_SIZE,
+						zft_deblock_buf) >= 0;
+	TRACE(ft_t_noise,
+	      "writing second header segment %d", ft_header_segment_2);
+	header_2_ok = zft_verify_write_segments(ft_header_segment_2, 
+						buffer, FT_SEGMENT_SIZE,
+						zft_deblock_buf) >= 0;
+	if (!header_1_ok) {
+		TRACE(ft_t_warn, "Warning: "
+		      "update of first header segment failed");
+	}
+	if (!header_2_ok) {
+		TRACE(ft_t_warn, "Warning: "
+		      "update of second header segment failed");
+	}
+	if (!header_1_ok && !header_2_ok) {
+		TRACE_ABORT(-EIO, ft_t_err, "Error: "
+		      "update of both header segments failed.");
+	}
+	TRACE_EXIT 0;
+}
+
+int zft_update_header_segments(void)
+{
+	TRACE_FUN(ft_t_noise);
+	
+	/*  must NOT use zft_write_protected, as it also includes the
+	 *  file access mode. But we also want to update when soft
+	 *  write protection is enabled (O_RDONLY)
+	 */
+	if (ft_write_protected || zft_old_ftape) {
+		TRACE_ABORT(0, ft_t_noise, "Tape set read-only: no update");
+	} 
+	if (!zft_header_read) {
+		TRACE_ABORT(0, ft_t_noise, "Nothing to update");
+	}
+	if (!zft_header_changed) {
+		zft_header_changed = zft_written_segments > 0;
+	}
+	if (!zft_header_changed && !zft_volume_table_changed) {
+		TRACE_ABORT(0, ft_t_noise, "Nothing to update");
+	}
+	TRACE(ft_t_noise, "Updating header segments");
+	if (ftape_get_status()->fti_state == writing) {
+		TRACE_CATCH(ftape_loop_until_writes_done(),);
+	}
+	TRACE_CATCH(ftape_abort_operation(),);
+	
+	zft_deblock_segment = -1; /* invalidate the cache */
+	if (zft_header_changed) {
+		TRACE_CATCH(zft_write_header_segments(zft_hseg_buf),);
+	}
+	if (zft_volume_table_changed) {
+		TRACE_CATCH(zft_update_volume_table(ft_first_data_segment),);
+	}
+	zft_header_changed =
+		zft_volume_table_changed = 
+		zft_label_changed        =
+		zft_written_segments     = 0;
+	TRACE_CATCH(ftape_abort_operation(),);
+	ftape_seek_to_bot();
+	TRACE_EXIT 0;
+}
+
+static int read_merge_buffer(int seg_pos, __u8 *buffer, int offset, int seg_sz)
+{
+	int result = 0;
+	const ft_trace_t old_tracing = TRACE_LEVEL;
+	TRACE_FUN(ft_t_flow);
+	
+	if (zft_qic_mode) {
+		/*  writing in the middle of a volume is NOT allowed
+		 *
+		 */
+		TRACE(ft_t_noise, "No need to read a segment");
+		memset(buffer + offset, 0, seg_sz - offset);
+		TRACE_EXIT 0;
+	}
+	TRACE(ft_t_any, "waiting");
+	ftape_start_writing(FT_WR_MULTI);
+	TRACE_CATCH(ftape_loop_until_writes_done(),);
+	
+	TRACE(ft_t_noise, "trying to read segment %d from offset %d",
+	      seg_pos, offset);
+	SET_TRACE_LEVEL(ft_t_bug);
+	result = zft_fetch_segment_fraction(seg_pos, buffer, 
+					    FT_RD_SINGLE,
+					    offset, seg_sz - offset);
+	SET_TRACE_LEVEL(old_tracing);
+	if (result != (seg_sz - offset)) {
+		TRACE(ft_t_noise, "Ignore error: read_segment() result: %d",
+		      result);
+		memset(buffer + offset, 0, seg_sz - offset);
+	}
+	TRACE_EXIT 0;
+}
+
+/* flush the write buffer to tape and write an eof-marker at the
+ * current position if not in raw mode.  This function always
+ * positions the tape before the eof-marker.  _ftape_close() should
+ * then advance to the next segment.
+ *
+ * the parameter "finish_volume" describes whether to position before
+ * or after the possibly created file-mark. We always position after
+ * the file-mark when called from ftape_close() and a flush was needed
+ * (that is ftape_write() was the last tape operation before calling
+ * ftape_flush) But we always position before the file-mark when this
+ * function get's called from outside ftape_close() 
+ */
+int zft_flush_buffers(void)
+{
+	int result;
+	int data_remaining;
+	int this_segs_size;
+	TRACE_FUN(ft_t_flow);
+
+	TRACE(ft_t_data_flow,
+	      "entered, ftape_state = %d", ftape_get_status()->fti_state);
+	if (ftape_get_status()->fti_state != writing && !need_flush) {
+		TRACE_ABORT(0, ft_t_noise, "no need for flush");
+	}
+	zft_io_state = zft_idle; /*  triggers some initializations for the
+				  *  read and write routines 
+				  */
+	if (last_write_failed) {
+		ftape_abort_operation();
+		TRACE_EXIT -EIO;
+	}
+	TRACE(ft_t_noise, "flushing write buffers");
+	this_segs_size = zft_get_seg_sz(zft_pos.seg_pos);
+	if (this_segs_size == zft_pos.seg_byte_pos) {
+		zft_pos.seg_pos ++;
+		data_remaining = zft_pos.seg_byte_pos = 0;
+	} else {
+		data_remaining = zft_pos.seg_byte_pos;
+	}
+	/* If there is any data not written to tape yet, append zero's
+	 * up to the end of the sector (if using compression) or merge
+	 * it with the data existing on the tape Then write the
+	 * segment(s) to tape.
+	 */
+	TRACE(ft_t_noise, "Position:\n"
+	      KERN_INFO "seg_pos  : %d\n"
+	      KERN_INFO "byte pos : %d\n"
+	      KERN_INFO "remaining: %d",
+	      zft_pos.seg_pos, zft_pos.seg_byte_pos, data_remaining);
+	if (data_remaining > 0) {
+		do {
+			this_segs_size = zft_get_seg_sz(zft_pos.seg_pos);
+			if (this_segs_size > data_remaining) {
+				TRACE_CATCH(read_merge_buffer(zft_pos.seg_pos,
+							      zft_deblock_buf,
+							      data_remaining,
+							      this_segs_size),
+					    last_write_failed = 1);
+			}
+			result = ftape_write_segment(zft_pos.seg_pos, 
+						     zft_deblock_buf,
+						     FT_WR_MULTI);
+			if (result != this_segs_size) {
+				TRACE(ft_t_err, "flush buffers failed");
+				zft_pos.tape_pos    -= zft_pos.seg_byte_pos;
+				zft_pos.seg_byte_pos = 0;
+
+				last_write_failed = 1;
+				TRACE_EXIT result;
+			}
+			zft_written_segments ++;
+			TRACE(ft_t_data_flow,
+			      "flush, moved out buffer: %d", result);
+			/* need next segment for more data (empty segments?)
+			 */
+			if (result < data_remaining) { 
+				if (result > 0) {       
+					/* move remainder to buffer beginning 
+					 */
+					memmove(zft_deblock_buf, 
+						zft_deblock_buf + result,
+						FT_SEGMENT_SIZE - result);
+				}
+			} 
+			data_remaining -= result;
+			zft_pos.seg_pos ++;
+		} while (data_remaining > 0);
+		TRACE(ft_t_any, "result: %d", result);
+		zft_deblock_segment = --zft_pos.seg_pos;
+		if (data_remaining == 0) {  /* first byte next segment */
+			zft_pos.seg_byte_pos = this_segs_size;
+		} else { /* after data previous segment, data_remaining < 0 */
+			zft_pos.seg_byte_pos = data_remaining + result;
+		}
+	} else {
+		TRACE(ft_t_noise, "zft_deblock_buf empty");
+		zft_pos.seg_pos --;
+		zft_pos.seg_byte_pos = zft_get_seg_sz (zft_pos.seg_pos);
+		ftape_start_writing(FT_WR_MULTI);
+	}
+	TRACE(ft_t_any, "waiting");
+	if ((result = ftape_loop_until_writes_done()) < 0) {
+		/* that's really bad. What to to with zft_tape_pos? 
+		 */
+		TRACE(ft_t_err, "flush buffers failed");
+	}
+	TRACE(ft_t_any, "zft_seg_pos: %d, zft_seg_byte_pos: %d",
+	      zft_pos.seg_pos, zft_pos.seg_byte_pos);
+	last_write_failed  =
+		need_flush = 0;
+	TRACE_EXIT result;
+}
+
+/* return-value: the number of bytes removed from the user-buffer
+ *
+ * out: 
+ *      int *write_cnt: how much actually has been moved to the
+ *                      zft_deblock_buf
+ *      int req_len  : MUST NOT BE CHANGED, except at EOT, in 
+ *                      which case it may be adjusted
+ * in : 
+ *      char *buff        : the user buffer
+ *      int buf_pos_write : copy of buf_len_wr int
+ *      this_segs_size    : the size in bytes of the actual segment
+ *                          char
+ *      *zft_deblock_buf   : zft_deblock_buf
+ */
+static int zft_simple_write(int *cnt,
+			    __u8 *dst_buf, const int seg_sz,
+			    const __u8 *src_buf, const int req_len, 
+			    const zft_position *pos,const zft_volinfo *volume)
+{
+	int space_left;
+	TRACE_FUN(ft_t_flow);
+
+	/* volume->size holds the tape capacity while volume is open */
+	if (pos->tape_pos + volume->blk_sz > volume->size) {
+		TRACE_EXIT -ENOSPC;
+	}
+	/*  remaining space in this segment, NOT zft_deblock_buf
+	 */
+	space_left = seg_sz - pos->seg_byte_pos;
+	*cnt = req_len < space_left ? req_len : space_left;
+#if LINUX_VERSION_CODE > KERNEL_VER(2,1,3)
+	if (copy_from_user(dst_buf + pos->seg_byte_pos, src_buf, *cnt) != 0) {
+		TRACE_EXIT -EFAULT;
+	}
+#else
+	TRACE_CATCH(verify_area(VERIFY_READ, src_buf, *cnt),);
+	memcpy_fromfs(dst_buf + pos->seg_byte_pos, src_buf, *cnt);
+#endif
+	TRACE_EXIT *cnt;
+}
+
+static int check_write_access(int req_len,
+			      const zft_volinfo **volume,
+			      zft_position *pos,
+			      const unsigned int blk_sz)
+{
+	int result;
+	TRACE_FUN(ft_t_flow);
+
+	if ((req_len % zft_blk_sz) != 0) {
+		TRACE_ABORT(-EINVAL, ft_t_info,
+			    "write-count %d must be multiple of block-size %d",
+			    req_len, blk_sz);
+	}
+	if (zft_io_state == zft_writing) {
+		/*  all other error conditions have been checked earlier
+		 */
+		TRACE_EXIT 0;
+	}
+	zft_io_state = zft_idle;
+	TRACE_CATCH(zft_check_write_access(pos),);
+	/*  If we haven't read the header segment yet, do it now.
+	 *  This will verify the configuration, get the bad sector
+	 *  table and read the volume table segment 
+	 */
+	if (!zft_header_read) {
+		TRACE_CATCH(zft_read_header_segments(),);
+	}
+	/*  fine. Now the tape is either at BOT or at EOD,
+	 *  Write start of volume now
+	 */
+	TRACE_CATCH(zft_open_volume(pos, blk_sz, zft_use_compression),);
+	*volume = zft_find_volume(pos->seg_pos);
+	DUMP_VOLINFO(ft_t_noise, "", *volume);
+	zft_just_before_eof = 0;
+	/* now merge with old data if neccessary */
+	if (!zft_qic_mode && pos->seg_byte_pos != 0){
+		result = zft_fetch_segment(pos->seg_pos,
+					   zft_deblock_buf,
+					   FT_RD_SINGLE);
+		if (result < 0) {
+			if (result == -EINTR || result == -ENOSPC) {
+				TRACE_EXIT result;
+			}
+			TRACE(ft_t_noise, 
+			      "ftape_read_segment() result: %d. "
+			      "This might be normal when using "
+			      "a newly\nformatted tape", result);
+			memset(zft_deblock_buf, '\0', pos->seg_byte_pos);
+		}
+	}
+	zft_io_state = zft_writing;
+	TRACE_EXIT 0;
+}
+
+static int fill_deblock_buf(__u8 *dst_buf, const int seg_sz,
+			    zft_position *pos, const zft_volinfo *volume,
+			    const char *usr_buf, const int req_len)
+{
+	int cnt = 0;
+	int result = 0;
+	TRACE_FUN(ft_t_flow);
+
+	if (seg_sz == 0) {
+		TRACE_ABORT(0, ft_t_data_flow, "empty segment");
+	}
+	TRACE(ft_t_data_flow, "\n"
+	      KERN_INFO "remaining req_len: %d\n"
+	      KERN_INFO "          buf_pos: %d", 
+	      req_len, pos->seg_byte_pos);
+	/* zft_deblock_buf will not contain a valid segment any longer */
+	zft_deblock_segment = -1;
+	if (zft_use_compression) {
+		TRACE_CATCH(zft_cmpr_lock(1 /* try to load */),);
+		TRACE_CATCH(result= (*zft_cmpr_ops->write)(&cnt,
+							   dst_buf, seg_sz,
+							   usr_buf, req_len,
+							   pos, volume),);
+	} else {
+		TRACE_CATCH(result= zft_simple_write(&cnt,
+						     dst_buf, seg_sz,
+						     usr_buf, req_len,
+						     pos, volume),);
+	}
+	pos->volume_pos   += result;
+	pos->seg_byte_pos += cnt;
+	pos->tape_pos     += cnt;
+	TRACE(ft_t_data_flow, "\n"
+	      KERN_INFO "removed from user-buffer : %d bytes.\n"
+	      KERN_INFO "copied to zft_deblock_buf: %d bytes.\n"
+	      KERN_INFO "zft_tape_pos             : " LL_X " bytes.",
+	      result, cnt, LL(pos->tape_pos));
+	TRACE_EXIT result;
+}
+
+
+/*  called by the kernel-interface routine "zft_write()"
+ */
+int _zft_write(const char* buff, int req_len)
+{
+	int result = 0;
+	int written = 0;
+	int write_cnt;
+	int seg_sz;
+	static const zft_volinfo *volume = NULL;
+	TRACE_FUN(ft_t_flow);
+	
+	zft_resid         = req_len;	
+	last_write_failed = 1; /* reset to 0 when successful */
+	/* check if write is allowed 
+	 */
+	TRACE_CATCH(check_write_access(req_len, &volume,&zft_pos,zft_blk_sz),);
+	while (req_len > 0) {
+		/* Allow us to escape from this loop with a signal !
+		 */
+		FT_SIGNAL_EXIT(_DONT_BLOCK);
+		seg_sz = zft_get_seg_sz(zft_pos.seg_pos);
+		if ((write_cnt = fill_deblock_buf(zft_deblock_buf,
+						  seg_sz,
+						  &zft_pos,
+						  volume,
+						  buff,
+						  req_len)) < 0) {
+			zft_resid -= written;
+			if (write_cnt == -ENOSPC) {
+				/* leave the remainder to flush_buffers()
+				 */
+				TRACE(ft_t_info, "No space left on device");
+				last_write_failed = 0;
+				if (!need_flush) {
+					need_flush = written > 0;
+				}
+				TRACE_EXIT written > 0 ? written : -ENOSPC;
+			} else {
+				TRACE_EXIT result;
+			}
+		}
+		if (zft_pos.seg_byte_pos == seg_sz) {
+			TRACE_CATCH(ftape_write_segment(zft_pos.seg_pos, 
+							zft_deblock_buf,
+							FT_WR_ASYNC),
+				    zft_resid -= written);
+			zft_written_segments ++;
+			zft_pos.seg_byte_pos =  0;
+			zft_deblock_segment  = zft_pos.seg_pos;
+			++zft_pos.seg_pos;
+		}
+		written += write_cnt;
+		buff    += write_cnt;
+		req_len -= write_cnt;
+	} /* while (req_len > 0) */
+	TRACE(ft_t_data_flow, "remaining in blocking buffer: %d",
+	       zft_pos.seg_byte_pos);
+	TRACE(ft_t_data_flow, "just written bytes: %d", written);
+	last_write_failed = 0;
+	zft_resid -= written;
+	need_flush = need_flush || written > 0;
+	TRACE_EXIT written;               /* bytes written */
+}