diff options
Diffstat (limited to 'drivers/char/ftape/zftape/zftape-read.c')
| -rw-r--r-- | drivers/char/ftape/zftape/zftape-read.c | 377 |
1 files changed, 0 insertions, 377 deletions
diff --git a/drivers/char/ftape/zftape/zftape-read.c b/drivers/char/ftape/zftape/zftape-read.c deleted file mode 100644 index 214bf03dce687b..00000000000000 --- a/drivers/char/ftape/zftape/zftape-read.c +++ /dev/null @@ -1,377 +0,0 @@ -/* - * Copyright (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/zftape/zftape-read.c,v $ - * $Revision: 1.2 $ - * $Date: 1997/10/05 19:19:06 $ - * - * This file contains the high level reading code - * for the QIC-117 floppy-tape driver for Linux. - */ - -#include <linux/errno.h> -#include <linux/mm.h> - -#include <linux/zftape.h> - -#include <asm/uaccess.h> - -#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. - */ -int zft_just_before_eof; - -/* Local vars. - */ -static int buf_len_rd; - -void zft_zap_read_buffers(void) -{ - buf_len_rd = 0; -} - -int zft_read_header_segments(void) -{ - TRACE_FUN(ft_t_flow); - - zft_header_read = 0; - TRACE_CATCH(zft_vmalloc_once(&zft_hseg_buf, FT_SEGMENT_SIZE),); - TRACE_CATCH(ftape_read_header_segment(zft_hseg_buf),); - TRACE(ft_t_info, "Segments written since first format: %d", - (int)GET4(zft_hseg_buf, FT_SEG_CNT)); - zft_qic113 = (ft_format_code != fmt_normal && - ft_format_code != fmt_1100ft && - ft_format_code != fmt_425ft); - TRACE(ft_t_info, "ft_first_data_segment: %d, ft_last_data_segment: %d", - ft_first_data_segment, ft_last_data_segment); - zft_capacity = zft_get_capacity(); - zft_old_ftape = zft_ftape_validate_label(&zft_hseg_buf[FT_LABEL]); - if (zft_old_ftape) { - TRACE(ft_t_info, -"Found old ftaped tape, emulating eof marks, entering read-only mode"); - zft_ftape_extract_file_marks(zft_hseg_buf); - TRACE_CATCH(zft_fake_volume_headers(zft_eof_map, - zft_nr_eof_marks),); - } else { - /* the specs say that the volume table must be - * initialized with zeroes during formatting, so it - * MUST be readable, i.e. contain vaid ECC - * information. - */ - TRACE_CATCH(ftape_read_segment(ft_first_data_segment, - zft_deblock_buf, - FT_RD_SINGLE),); - TRACE_CATCH(zft_extract_volume_headers(zft_deblock_buf),); - } - zft_header_read = 1; - zft_set_flags(zft_unit); - zft_reset_position(&zft_pos); - TRACE_EXIT 0; -} - -int zft_fetch_segment_fraction(const unsigned int segment, void *buffer, - const ft_read_mode_t read_mode, - const unsigned int start, - const unsigned int size) -{ - int seg_sz; - TRACE_FUN(ft_t_flow); - - if (segment == zft_deblock_segment) { - TRACE(ft_t_data_flow, - "re-using segment %d already in deblock buffer", - segment); - seg_sz = zft_get_seg_sz(segment); - if (start > seg_sz) { - TRACE_ABORT(-EINVAL, ft_t_bug, - "trying to read beyond end of segment:\n" - KERN_INFO "seg_sz : %d\n" - KERN_INFO "start : %d\n" - KERN_INFO "segment: %d", - seg_sz, start, segment); - } - if ((start + size) > seg_sz) { - TRACE_EXIT seg_sz - start; - } - TRACE_EXIT size; - } - seg_sz = ftape_read_segment_fraction(segment, buffer, read_mode, - start, size); - TRACE(ft_t_data_flow, "segment %d, result %d", segment, seg_sz); - if ((int)seg_sz >= 0 && start == 0 && size == FT_SEGMENT_SIZE) { - /* this implicitly assumes that we are always called with - * buffer == zft_deblock_buf - */ - zft_deblock_segment = segment; - } else { - zft_deblock_segment = -1; - } - TRACE_EXIT seg_sz; -} - -/* - * out: - * - * int *read_cnt: the number of bytes we removed from the - * zft_deblock_buf (result) - * - * int *to_do : the remaining size of the read-request. Is changed. - * - * in: - * - * char *buff : buff is the address of the upper part of the user - * buffer, that hasn't been filled with data yet. - * int buf_pos_read: copy of buf_pos_rd - * int buf_len_read: copy of buf_len_rd - * char *zft_deblock_buf: ftape_zft_deblock_buf - * - * returns the amount of data actually copied to the user-buffer - * - * to_do MUST NOT SHRINK except to indicate an EOT. In this case to_do - * has to be set to 0. We cannot return -ENOSPC, because we return the - * amount of data actually * copied to the user-buffer - */ -static int zft_simple_read (int *read_cnt, - __u8 __user *dst_buf, - const int to_do, - const __u8 *src_buf, - const int seg_sz, - const zft_position *pos, - const zft_volinfo *volume) -{ - TRACE_FUN(ft_t_flow); - - if (seg_sz - pos->seg_byte_pos < to_do) { - *read_cnt = seg_sz - pos->seg_byte_pos; - } else { - *read_cnt = to_do; - } - if (copy_to_user(dst_buf, - src_buf + pos->seg_byte_pos, *read_cnt) != 0) { - TRACE_EXIT -EFAULT; - } - TRACE(ft_t_noise, "nr bytes just read: %d", *read_cnt); - TRACE_EXIT *read_cnt; -} - -/* req_len: gets clipped due to EOT of EOF. - * req_clipped: is a flag indicating whether req_len was clipped or not - * volume: contains information on current volume (blk_sz etc.) - */ -static int check_read_access(int *req_len, - const zft_volinfo **volume, - int *req_clipped, - const zft_position *pos) -{ - static __s64 remaining; - static int eod; - TRACE_FUN(ft_t_flow); - - if (zft_io_state != zft_reading) { - if (zft_offline) { /* offline includes no_tape */ - TRACE_ABORT(-ENXIO, ft_t_warn, - "tape is offline or no cartridge"); - } - if (!ft_formatted) { - TRACE_ABORT(-EACCES, - ft_t_warn, "tape is not formatted"); - } - /* now enter defined state, read header segment if not - * already done and flush write buffers - */ - TRACE_CATCH(zft_def_idle_state(),); - zft_io_state = zft_reading; - if (zft_tape_at_eod(pos)) { - eod = 1; - TRACE_EXIT 1; - } - eod = 0; - *volume = zft_find_volume(pos->seg_pos); - /* get the space left until EOF */ - remaining = zft_check_for_eof(*volume, pos); - buf_len_rd = 0; - TRACE(ft_t_noise, "remaining: " LL_X ", vol_no: %d", - LL(remaining), (*volume)->count); - } else if (zft_tape_at_eod(pos)) { - if (++eod > 2) { - TRACE_EXIT -EIO; /* st.c also returns -EIO */ - } else { - TRACE_EXIT 1; - } - } - if ((*req_len % (*volume)->blk_sz) != 0) { - /* this message is informational only. The user gets the - * proper return value - */ - TRACE_ABORT(-EINVAL, ft_t_info, - "req_len %d not a multiple of block size %d", - *req_len, (*volume)->blk_sz); - } - /* As GNU tar doesn't accept partial read counts when the - * multiple volume flag is set, we make sure to return the - * requested amount of data. Except, of course, at the end of - * the tape or file mark. - */ - remaining -= *req_len; - if (remaining <= 0) { - TRACE(ft_t_noise, - "clipped request from %d to %d.", - *req_len, (int)(*req_len + remaining)); - *req_len += remaining; - *req_clipped = 1; - } else { - *req_clipped = 0; - } - TRACE_EXIT 0; -} - -/* this_segs_size: the current segment's size. - * buff: the USER-SPACE buffer provided by the calling function. - * req_len: how much data should be read at most. - * volume: contains information on current volume (blk_sz etc.) - */ -static int empty_deblock_buf(__u8 __user *usr_buf, const int req_len, - const __u8 *src_buf, const int seg_sz, - zft_position *pos, - const zft_volinfo *volume) -{ - int cnt; - int result = 0; - TRACE_FUN(ft_t_flow); - - TRACE(ft_t_data_flow, "this_segs_size: %d", seg_sz); - if (zft_use_compression && volume->use_compression) { - TRACE_CATCH(zft_cmpr_lock(1 /* try to load */),); - TRACE_CATCH(result= (*zft_cmpr_ops->read)(&cnt, - usr_buf, req_len, - src_buf, seg_sz, - pos, volume),); - } else { - TRACE_CATCH(result= zft_simple_read (&cnt, - usr_buf, req_len, - src_buf, seg_sz, - pos, volume),); - } - pos->volume_pos += result; - pos->tape_pos += cnt; - pos->seg_byte_pos += cnt; - buf_len_rd -= cnt; /* remaining bytes in buffer */ - TRACE(ft_t_data_flow, "buf_len_rd: %d, cnt: %d", buf_len_rd, cnt); - if(pos->seg_byte_pos >= seg_sz) { - pos->seg_pos++; - pos->seg_byte_pos = 0; - } - TRACE(ft_t_data_flow, "bytes moved out of deblock-buffer: %d", cnt); - TRACE_EXIT result; -} - - -/* note: we store the segment id of the segment that is inside the - * deblock buffer. This spares a lot of ftape_read_segment()s when we - * use small block-sizes. The block-size may be 1kb (SECTOR_SIZE). In - * this case a MTFSR 28 maybe still inside the same segment. - */ -int _zft_read(char __user *buff, int req_len) -{ - int req_clipped; - int result = 0; - int bytes_read = 0; - static unsigned int seg_sz = 0; - static const zft_volinfo *volume = NULL; - TRACE_FUN(ft_t_flow); - - zft_resid = req_len; - result = check_read_access(&req_len, &volume, - &req_clipped, &zft_pos); - switch(result) { - case 0: - break; /* nothing special */ - case 1: - TRACE(ft_t_noise, "EOD reached"); - TRACE_EXIT 0; /* EOD */ - default: - TRACE_ABORT(result, ft_t_noise, - "check_read_access() failed with result %d", - result); - TRACE_EXIT result; - } - while (req_len > 0) { - /* Allow escape from this loop on signal ! - */ - FT_SIGNAL_EXIT(_DONT_BLOCK); - /* buf_len_rd == 0 means that we need to read a new - * segment. - */ - if (buf_len_rd == 0) { - while((result = zft_fetch_segment(zft_pos.seg_pos, - zft_deblock_buf, - FT_RD_AHEAD)) == 0) { - zft_pos.seg_pos ++; - zft_pos.seg_byte_pos = 0; - } - if (result < 0) { - zft_resid -= bytes_read; - TRACE_ABORT(result, ft_t_noise, - "zft_fetch_segment(): %d", - result); - } - seg_sz = result; - buf_len_rd = seg_sz - zft_pos.seg_byte_pos; - } - TRACE_CATCH(result = empty_deblock_buf(buff, - req_len, - zft_deblock_buf, - seg_sz, - &zft_pos, - volume), - zft_resid -= bytes_read); - TRACE(ft_t_data_flow, "bytes just read: %d", result); - bytes_read += result; /* what we got so far */ - buff += result; /* index in user-buffer */ - req_len -= result; /* what's left from req_len */ - } /* while (req_len > 0) */ - if (req_clipped) { - TRACE(ft_t_data_flow, - "maybe partial count because of eof mark"); - if (zft_just_before_eof && bytes_read == 0) { - /* req_len was > 0, but user didn't get - * anything the user has read in the eof-mark - */ - zft_move_past_eof(&zft_pos); - ftape_abort_operation(); - } else { - /* don't skip to the next file before the user - * tried to read a second time past EOF Just - * mark that we are at EOF and maybe decrement - * zft_seg_pos to stay in the same volume; - */ - zft_just_before_eof = 1; - zft_position_before_eof(&zft_pos, volume); - TRACE(ft_t_noise, "just before eof"); - } - } - zft_resid -= result; /* for MTSTATUS */ - TRACE_EXIT bytes_read; -} |