1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
484 lines
14 KiB
C
484 lines
14 KiB
C
/*
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* Copyright (C) 1996, 1997 Claus Heine
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Source: /homes/cvs/ftape-stacked/ftape/zftape/zftape-write.c,v $
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* $Revision: 1.3 $
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* $Date: 1997/11/06 00:50:29 $
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*
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* This file contains the writing code
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* for the QIC-117 floppy-tape driver for Linux.
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*/
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/zftape.h>
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#include <asm/uaccess.h>
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#include "../zftape/zftape-init.h"
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#include "../zftape/zftape-eof.h"
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#include "../zftape/zftape-ctl.h"
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#include "../zftape/zftape-write.h"
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#include "../zftape/zftape-read.h"
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#include "../zftape/zftape-rw.h"
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#include "../zftape/zftape-vtbl.h"
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/* Global vars.
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*/
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/* Local vars.
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*/
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static int last_write_failed;
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static int need_flush;
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void zft_prevent_flush(void)
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{
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need_flush = 0;
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}
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static int zft_write_header_segments(__u8* buffer)
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{
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int header_1_ok = 0;
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int header_2_ok = 0;
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unsigned int time_stamp;
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TRACE_FUN(ft_t_noise);
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TRACE_CATCH(ftape_abort_operation(),);
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ftape_seek_to_bot(); /* prevents extra rewind */
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if (GET4(buffer, 0) != FT_HSEG_MAGIC) {
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TRACE_ABORT(-EIO, ft_t_err,
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"wrong header signature found, aborting");
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}
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/* Be optimistic: */
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PUT4(buffer, FT_SEG_CNT,
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zft_written_segments + GET4(buffer, FT_SEG_CNT) + 2);
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if ((time_stamp = zft_get_time()) != 0) {
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PUT4(buffer, FT_WR_DATE, time_stamp);
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if (zft_label_changed) {
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PUT4(buffer, FT_LABEL_DATE, time_stamp);
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}
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}
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TRACE(ft_t_noise,
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"writing first header segment %d", ft_header_segment_1);
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header_1_ok = zft_verify_write_segments(ft_header_segment_1,
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buffer, FT_SEGMENT_SIZE,
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zft_deblock_buf) >= 0;
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TRACE(ft_t_noise,
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"writing second header segment %d", ft_header_segment_2);
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header_2_ok = zft_verify_write_segments(ft_header_segment_2,
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buffer, FT_SEGMENT_SIZE,
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zft_deblock_buf) >= 0;
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if (!header_1_ok) {
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TRACE(ft_t_warn, "Warning: "
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"update of first header segment failed");
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}
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if (!header_2_ok) {
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TRACE(ft_t_warn, "Warning: "
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"update of second header segment failed");
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}
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if (!header_1_ok && !header_2_ok) {
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TRACE_ABORT(-EIO, ft_t_err, "Error: "
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"update of both header segments failed.");
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}
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TRACE_EXIT 0;
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}
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int zft_update_header_segments(void)
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{
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TRACE_FUN(ft_t_noise);
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/* must NOT use zft_write_protected, as it also includes the
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* file access mode. But we also want to update when soft
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* write protection is enabled (O_RDONLY)
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*/
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if (ft_write_protected || zft_old_ftape) {
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TRACE_ABORT(0, ft_t_noise, "Tape set read-only: no update");
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}
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if (!zft_header_read) {
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TRACE_ABORT(0, ft_t_noise, "Nothing to update");
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}
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if (!zft_header_changed) {
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zft_header_changed = zft_written_segments > 0;
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}
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if (!zft_header_changed && !zft_volume_table_changed) {
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TRACE_ABORT(0, ft_t_noise, "Nothing to update");
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}
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TRACE(ft_t_noise, "Updating header segments");
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if (ftape_get_status()->fti_state == writing) {
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TRACE_CATCH(ftape_loop_until_writes_done(),);
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}
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TRACE_CATCH(ftape_abort_operation(),);
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zft_deblock_segment = -1; /* invalidate the cache */
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if (zft_header_changed) {
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TRACE_CATCH(zft_write_header_segments(zft_hseg_buf),);
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}
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if (zft_volume_table_changed) {
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TRACE_CATCH(zft_update_volume_table(ft_first_data_segment),);
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}
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zft_header_changed =
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zft_volume_table_changed =
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zft_label_changed =
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zft_written_segments = 0;
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TRACE_CATCH(ftape_abort_operation(),);
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ftape_seek_to_bot();
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TRACE_EXIT 0;
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}
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static int read_merge_buffer(int seg_pos, __u8 *buffer, int offset, int seg_sz)
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{
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int result = 0;
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const ft_trace_t old_tracing = TRACE_LEVEL;
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TRACE_FUN(ft_t_flow);
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if (zft_qic_mode) {
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/* writing in the middle of a volume is NOT allowed
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*
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*/
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TRACE(ft_t_noise, "No need to read a segment");
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memset(buffer + offset, 0, seg_sz - offset);
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TRACE_EXIT 0;
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}
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TRACE(ft_t_any, "waiting");
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ftape_start_writing(FT_WR_MULTI);
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TRACE_CATCH(ftape_loop_until_writes_done(),);
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TRACE(ft_t_noise, "trying to read segment %d from offset %d",
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seg_pos, offset);
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SET_TRACE_LEVEL(ft_t_bug);
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result = zft_fetch_segment_fraction(seg_pos, buffer,
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FT_RD_SINGLE,
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offset, seg_sz - offset);
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SET_TRACE_LEVEL(old_tracing);
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if (result != (seg_sz - offset)) {
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TRACE(ft_t_noise, "Ignore error: read_segment() result: %d",
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result);
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memset(buffer + offset, 0, seg_sz - offset);
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}
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TRACE_EXIT 0;
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}
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/* flush the write buffer to tape and write an eof-marker at the
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* current position if not in raw mode. This function always
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* positions the tape before the eof-marker. _ftape_close() should
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* then advance to the next segment.
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*
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* the parameter "finish_volume" describes whether to position before
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* or after the possibly created file-mark. We always position after
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* the file-mark when called from ftape_close() and a flush was needed
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* (that is ftape_write() was the last tape operation before calling
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* ftape_flush) But we always position before the file-mark when this
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* function get's called from outside ftape_close()
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*/
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int zft_flush_buffers(void)
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{
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int result;
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int data_remaining;
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int this_segs_size;
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TRACE_FUN(ft_t_flow);
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TRACE(ft_t_data_flow,
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"entered, ftape_state = %d", ftape_get_status()->fti_state);
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if (ftape_get_status()->fti_state != writing && !need_flush) {
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TRACE_ABORT(0, ft_t_noise, "no need for flush");
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}
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zft_io_state = zft_idle; /* triggers some initializations for the
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* read and write routines
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*/
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if (last_write_failed) {
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ftape_abort_operation();
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TRACE_EXIT -EIO;
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}
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TRACE(ft_t_noise, "flushing write buffers");
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this_segs_size = zft_get_seg_sz(zft_pos.seg_pos);
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if (this_segs_size == zft_pos.seg_byte_pos) {
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zft_pos.seg_pos ++;
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data_remaining = zft_pos.seg_byte_pos = 0;
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} else {
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data_remaining = zft_pos.seg_byte_pos;
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}
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/* If there is any data not written to tape yet, append zero's
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* up to the end of the sector (if using compression) or merge
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* it with the data existing on the tape Then write the
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* segment(s) to tape.
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*/
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TRACE(ft_t_noise, "Position:\n"
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KERN_INFO "seg_pos : %d\n"
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KERN_INFO "byte pos : %d\n"
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KERN_INFO "remaining: %d",
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zft_pos.seg_pos, zft_pos.seg_byte_pos, data_remaining);
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if (data_remaining > 0) {
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do {
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this_segs_size = zft_get_seg_sz(zft_pos.seg_pos);
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if (this_segs_size > data_remaining) {
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TRACE_CATCH(read_merge_buffer(zft_pos.seg_pos,
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zft_deblock_buf,
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data_remaining,
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this_segs_size),
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last_write_failed = 1);
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}
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result = ftape_write_segment(zft_pos.seg_pos,
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zft_deblock_buf,
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FT_WR_MULTI);
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if (result != this_segs_size) {
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TRACE(ft_t_err, "flush buffers failed");
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zft_pos.tape_pos -= zft_pos.seg_byte_pos;
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zft_pos.seg_byte_pos = 0;
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last_write_failed = 1;
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TRACE_EXIT result;
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}
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zft_written_segments ++;
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TRACE(ft_t_data_flow,
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"flush, moved out buffer: %d", result);
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/* need next segment for more data (empty segments?)
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*/
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if (result < data_remaining) {
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if (result > 0) {
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/* move remainder to buffer beginning
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*/
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memmove(zft_deblock_buf,
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zft_deblock_buf + result,
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FT_SEGMENT_SIZE - result);
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}
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}
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data_remaining -= result;
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zft_pos.seg_pos ++;
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} while (data_remaining > 0);
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TRACE(ft_t_any, "result: %d", result);
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zft_deblock_segment = --zft_pos.seg_pos;
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if (data_remaining == 0) { /* first byte next segment */
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zft_pos.seg_byte_pos = this_segs_size;
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} else { /* after data previous segment, data_remaining < 0 */
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zft_pos.seg_byte_pos = data_remaining + result;
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}
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} else {
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TRACE(ft_t_noise, "zft_deblock_buf empty");
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zft_pos.seg_pos --;
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zft_pos.seg_byte_pos = zft_get_seg_sz (zft_pos.seg_pos);
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ftape_start_writing(FT_WR_MULTI);
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}
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TRACE(ft_t_any, "waiting");
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if ((result = ftape_loop_until_writes_done()) < 0) {
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/* that's really bad. What to to with zft_tape_pos?
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*/
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TRACE(ft_t_err, "flush buffers failed");
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}
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TRACE(ft_t_any, "zft_seg_pos: %d, zft_seg_byte_pos: %d",
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zft_pos.seg_pos, zft_pos.seg_byte_pos);
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last_write_failed =
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need_flush = 0;
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TRACE_EXIT result;
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}
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/* return-value: the number of bytes removed from the user-buffer
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*
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* out:
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* int *write_cnt: how much actually has been moved to the
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* zft_deblock_buf
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* int req_len : MUST NOT BE CHANGED, except at EOT, in
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* which case it may be adjusted
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* in :
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* char *buff : the user buffer
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* int buf_pos_write : copy of buf_len_wr int
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* this_segs_size : the size in bytes of the actual segment
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* char
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* *zft_deblock_buf : zft_deblock_buf
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*/
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static int zft_simple_write(int *cnt,
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__u8 *dst_buf, const int seg_sz,
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const __u8 __user *src_buf, const int req_len,
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const zft_position *pos,const zft_volinfo *volume)
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{
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int space_left;
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TRACE_FUN(ft_t_flow);
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/* volume->size holds the tape capacity while volume is open */
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if (pos->tape_pos + volume->blk_sz > volume->size) {
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TRACE_EXIT -ENOSPC;
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}
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/* remaining space in this segment, NOT zft_deblock_buf
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*/
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space_left = seg_sz - pos->seg_byte_pos;
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*cnt = req_len < space_left ? req_len : space_left;
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if (copy_from_user(dst_buf + pos->seg_byte_pos, src_buf, *cnt) != 0) {
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TRACE_EXIT -EFAULT;
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}
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TRACE_EXIT *cnt;
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}
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static int check_write_access(int req_len,
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const zft_volinfo **volume,
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zft_position *pos,
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const unsigned int blk_sz)
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{
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int result;
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TRACE_FUN(ft_t_flow);
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if ((req_len % zft_blk_sz) != 0) {
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TRACE_ABORT(-EINVAL, ft_t_info,
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"write-count %d must be multiple of block-size %d",
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req_len, blk_sz);
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}
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if (zft_io_state == zft_writing) {
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/* all other error conditions have been checked earlier
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*/
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TRACE_EXIT 0;
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}
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zft_io_state = zft_idle;
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TRACE_CATCH(zft_check_write_access(pos),);
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/* If we haven't read the header segment yet, do it now.
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* This will verify the configuration, get the bad sector
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* table and read the volume table segment
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*/
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if (!zft_header_read) {
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TRACE_CATCH(zft_read_header_segments(),);
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}
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/* fine. Now the tape is either at BOT or at EOD,
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* Write start of volume now
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*/
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TRACE_CATCH(zft_open_volume(pos, blk_sz, zft_use_compression),);
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*volume = zft_find_volume(pos->seg_pos);
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DUMP_VOLINFO(ft_t_noise, "", *volume);
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zft_just_before_eof = 0;
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/* now merge with old data if necessary */
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if (!zft_qic_mode && pos->seg_byte_pos != 0){
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result = zft_fetch_segment(pos->seg_pos,
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zft_deblock_buf,
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FT_RD_SINGLE);
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if (result < 0) {
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if (result == -EINTR || result == -ENOSPC) {
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TRACE_EXIT result;
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}
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TRACE(ft_t_noise,
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"ftape_read_segment() result: %d. "
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"This might be normal when using "
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"a newly\nformatted tape", result);
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memset(zft_deblock_buf, '\0', pos->seg_byte_pos);
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}
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}
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zft_io_state = zft_writing;
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TRACE_EXIT 0;
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}
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static int fill_deblock_buf(__u8 *dst_buf, const int seg_sz,
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zft_position *pos, const zft_volinfo *volume,
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const char __user *usr_buf, const int req_len)
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{
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int cnt = 0;
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int result = 0;
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TRACE_FUN(ft_t_flow);
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if (seg_sz == 0) {
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TRACE_ABORT(0, ft_t_data_flow, "empty segment");
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}
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TRACE(ft_t_data_flow, "\n"
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KERN_INFO "remaining req_len: %d\n"
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KERN_INFO " buf_pos: %d",
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req_len, pos->seg_byte_pos);
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/* zft_deblock_buf will not contain a valid segment any longer */
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zft_deblock_segment = -1;
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if (zft_use_compression) {
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TRACE_CATCH(zft_cmpr_lock(1 /* try to load */),);
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TRACE_CATCH(result= (*zft_cmpr_ops->write)(&cnt,
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dst_buf, seg_sz,
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usr_buf, req_len,
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pos, volume),);
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} else {
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TRACE_CATCH(result= zft_simple_write(&cnt,
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dst_buf, seg_sz,
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usr_buf, req_len,
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pos, volume),);
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}
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pos->volume_pos += result;
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pos->seg_byte_pos += cnt;
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pos->tape_pos += cnt;
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TRACE(ft_t_data_flow, "\n"
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KERN_INFO "removed from user-buffer : %d bytes.\n"
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KERN_INFO "copied to zft_deblock_buf: %d bytes.\n"
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KERN_INFO "zft_tape_pos : " LL_X " bytes.",
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result, cnt, LL(pos->tape_pos));
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TRACE_EXIT result;
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}
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/* called by the kernel-interface routine "zft_write()"
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*/
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int _zft_write(const char __user *buff, int req_len)
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{
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int result = 0;
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int written = 0;
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int write_cnt;
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int seg_sz;
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static const zft_volinfo *volume = NULL;
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TRACE_FUN(ft_t_flow);
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zft_resid = req_len;
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last_write_failed = 1; /* reset to 0 when successful */
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/* check if write is allowed
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*/
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TRACE_CATCH(check_write_access(req_len, &volume,&zft_pos,zft_blk_sz),);
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while (req_len > 0) {
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/* Allow us to escape from this loop with a signal !
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*/
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FT_SIGNAL_EXIT(_DONT_BLOCK);
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seg_sz = zft_get_seg_sz(zft_pos.seg_pos);
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if ((write_cnt = fill_deblock_buf(zft_deblock_buf,
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seg_sz,
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&zft_pos,
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volume,
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buff,
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req_len)) < 0) {
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zft_resid -= written;
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if (write_cnt == -ENOSPC) {
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/* leave the remainder to flush_buffers()
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*/
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TRACE(ft_t_info, "No space left on device");
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last_write_failed = 0;
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if (!need_flush) {
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need_flush = written > 0;
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}
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TRACE_EXIT written > 0 ? written : -ENOSPC;
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} else {
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TRACE_EXIT result;
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}
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}
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if (zft_pos.seg_byte_pos == seg_sz) {
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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 */
|
|
}
|