zftape-vtbl.c

linux-2.6.15.6

/*
 *      Copyright (c) 1995-1997 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-vtbl.c,v $
 * $Revision: 1.7.6.1 $
 * $Date: 1997/11/24 13:48:31 $
 *
 *      This file defines a volume table as defined in various QIC
 *      standards.
 * 
 *      This is a minimal implementation, just allowing ordinary DOS
 *      :( prgrams to identify the cartridge as used.
 */

#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/slab.h>

#include <linux/zftape.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"

#define ZFT_CMAP_HACK /* leave this defined to hide the compression map */

/*
 *  global variables 
 */
int zft_qic_mode   = 1; /* use the vtbl */
int zft_old_ftape; /* prevents old ftaped tapes to be overwritten */
int zft_volume_table_changed; /* for write_header_segments() */

/*
 *  private variables (only exported for inline functions)
 */
LIST_HEAD(zft_vtbl);

/*  We could also allocate these dynamically when extracting the volume table
 *  sizeof(zft_volinfo) is about 32 or something close to that
 */
static zft_volinfo  tape_vtbl;
static zft_volinfo  eot_vtbl;
static zft_volinfo *cur_vtbl;

static inline void zft_new_vtbl_entry(void)
{
	struct list_head *tmp = &zft_last_vtbl->node;
	zft_volinfo *new = zft_kmalloc(sizeof(zft_volinfo));

	list_add(&new->node, tmp);
	new->count = zft_eom_vtbl->count ++;
}

void zft_free_vtbl(void)
{
	for (;;) {
		struct list_head *tmp = zft_vtbl.prev;
		zft_volinfo *vtbl;

		if (tmp == &zft_vtbl)
			break;
		list_del(tmp);
		vtbl = list_entry(tmp, zft_volinfo, node);
		zft_kfree(vtbl, sizeof(zft_volinfo));
	}
	INIT_LIST_HEAD(&zft_vtbl);
	cur_vtbl = NULL;
}

/*  initialize vtbl, called by ftape_new_cartridge()
 */
void zft_init_vtbl(void)
{ 
	zft_volinfo *new;

	zft_free_vtbl();
	
	/*  Create the two dummy vtbl entries
	 */
	new = zft_kmalloc(sizeof(zft_volinfo));
	list_add(&new->node, &zft_vtbl);
	new = zft_kmalloc(sizeof(zft_volinfo));
	list_add(&new->node, &zft_vtbl);
	zft_head_vtbl->end_seg   = ft_first_data_segment;
	zft_head_vtbl->blk_sz    = zft_blk_sz;
	zft_head_vtbl->count     = -1;
	zft_eom_vtbl->start_seg  = ft_first_data_segment + 1;
	zft_eom_vtbl->end_seg    = ft_last_data_segment + 1;
	zft_eom_vtbl->blk_sz     = zft_blk_sz;
	zft_eom_vtbl->count      = 0;

	/*  Reset the pointer for zft_find_volume()
	 */
	cur_vtbl = zft_eom_vtbl;

	/* initialize the dummy vtbl entries for zft_qic_mode == 0
	 */
	eot_vtbl.start_seg       = ft_last_data_segment + 1;
	eot_vtbl.end_seg         = ft_last_data_segment + 1;
	eot_vtbl.blk_sz          = zft_blk_sz;
	eot_vtbl.count           = -1;
	tape_vtbl.start_seg = ft_first_data_segment;
	tape_vtbl.end_seg   = ft_last_data_segment;
	tape_vtbl.blk_sz    = zft_blk_sz;
	tape_vtbl.size      = zft_capacity;
	tape_vtbl.count     = 0;
}

/* check for a valid VTBL signature. 
 */
static int vtbl_signature_valid(__u8 signature[4])
{
	const char *vtbl_ids[] = VTBL_IDS; /* valid signatures */
	int j;
	
	for (j = 0; 
	     (j < NR_ITEMS(vtbl_ids)) && (memcmp(signature, vtbl_ids[j], 4) != 0);
	     j++);
	return j < NR_ITEMS(vtbl_ids);
}

/* We used to store the block-size of the volume in the volume-label,
 * using the keyword "blocksize". The blocksize written to the
 * volume-label is in bytes.
 *
 * We use this now only for compatibility with old zftape version. We
 * store the blocksize directly as binary number in the vendor
 * extension part of the volume entry.
 */
static int check_volume_label(const char *label, int *blk_sz)
{ 
	int valid_format;
	char *blocksize;
	TRACE_FUN(ft_t_flow);
	
	TRACE(ft_t_noise, "called with \"%s\" / \"%s\"", label, ZFT_VOL_NAME);
	if (strncmp(label, ZFT_VOL_NAME, strlen(ZFT_VOL_NAME)) != 0) {
		*blk_sz = 1; /* smallest block size that we allow */
		valid_format = 0;
	} else {
		TRACE(ft_t_noise, "got old style zftape vtbl entry");
		/* get the default blocksize */
		/* use the kernel strstr()   */
		blocksize= strstr(label, " blocksize ");
		if (blocksize) {
			blocksize += strlen(" blocksize ");
			for(*blk_sz= 0; 
			    *blocksize >= '0' && *blocksize <= '9'; 
			    blocksize++) {
				*blk_sz *= 10;
				*blk_sz += *blocksize - '0';
			}
			if (*blk_sz > ZFT_MAX_BLK_SZ) {
				*blk_sz= 1;
				valid_format= 0;
			} else {
				valid_format = 1;
			}
		} else {
			*blk_sz= 1;
			valid_format= 0;
		}
	}
	TRACE_EXIT valid_format;
}

/*   check for a zftape volume
 */
static int check_volume(__u8 *entry, zft_volinfo *volume)
{
	TRACE_FUN(ft_t_flow);
	
	if(strncmp(&entry[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG,
		   strlen(ZFTAPE_SIG)) == 0) {
		TRACE(ft_t_noise, "got new style zftape vtbl entry");
		volume->blk_sz = GET2(entry, VTBL_EXT+EXT_ZFTAPE_BLKSZ);
		volume->qic113 = entry[VTBL_EXT+EXT_ZFTAPE_QIC113];
		TRACE_EXIT 1;
	} else {
		TRACE_EXIT check_volume_label(&entry[VTBL_DESC], &volume->blk_sz);
	}
}


/* create zftape specific vtbl entry, the volume bounds are inserted
 * in the calling function, zft_create_volume_headers()
 */
static void create_zft_volume(__u8 *entry, zft_volinfo *vtbl)
{
	TRACE_FUN(ft_t_flow);

	memset(entry, 0, VTBL_SIZE);
	memcpy(&entry[VTBL_SIG], VTBL_ID, 4);
	sprintf(&entry[VTBL_DESC], ZFT_VOL_NAME" %03d", vtbl->count);
	entry[VTBL_FLAGS] = (VTBL_FL_NOT_VERIFIED | VTBL_FL_SEG_SPANNING);
	entry[VTBL_M_NO] = 1; /* multi_cartridge_count */
	strcpy(&entry[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG);
	PUT2(entry, VTBL_EXT+EXT_ZFTAPE_BLKSZ, vtbl->blk_sz);
	if (zft_qic113) {
		PUT8(entry, VTBL_DATA_SIZE, vtbl->size);
		entry[VTBL_CMPR] = VTBL_CMPR_UNREG; 
		if (vtbl->use_compression) { /* use compression: */
			entry[VTBL_CMPR] |= VTBL_CMPR_USED;
		}
		entry[VTBL_EXT+EXT_ZFTAPE_QIC113] = 1;
	} else {
		PUT4(entry, VTBL_DATA_SIZE, vtbl->size);
		entry[VTBL_K_CMPR] = VTBL_CMPR_UNREG; 
		if (vtbl->use_compression) { /* use compression: */
			entry[VTBL_K_CMPR] |= VTBL_CMPR_USED;
		}
	}
	if (ft_format_code == fmt_big) {
		/* SCSI like vtbl, store the number of used
		 * segments as 4 byte value 
		 */
		PUT4(entry, VTBL_SCSI_SEGS, vtbl->end_seg-vtbl->start_seg + 1);
	} else {
		/* normal, QIC-80MC like vtbl 
		 */
		PUT2(entry, VTBL_START, vtbl->start_seg);
		PUT2(entry, VTBL_END, vtbl->end_seg);
	}
	TRACE_EXIT;
}

/* this one creates the volume headers for each volume. It is assumed
 * that buffer already contains the old volume-table, so that vtbl
 * entries without the zft_volume flag set can savely be ignored.
 */
static void zft_create_volume_headers(__u8 *buffer)
{   
	__u8 *entry;
	struct list_head *tmp;
	zft_volinfo *vtbl;
	TRACE_FUN(ft_t_flow);
	
#ifdef ZFT_CMAP_HACK
	if((strncmp(&buffer[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG,
		    strlen(ZFTAPE_SIG)) == 0) && 
	   buffer[VTBL_EXT+EXT_ZFTAPE_CMAP] != 0) {
		TRACE(ft_t_noise, "deleting cmap volume");
		memmove(buffer, buffer + VTBL_SIZE,
			FT_SEGMENT_SIZE - VTBL_SIZE);
	}
#endif
	entry = buffer;
	for (tmp = zft_head_vtbl->node.next;
	     tmp != &zft_eom_vtbl->node;
	     tmp = tmp->next) {
		vtbl = list_entry(tmp, zft_volinfo, node);
		/* we now fill in the values only for newly created volumes.
		 */
		if (vtbl->new_volume) {
			create_zft_volume(entry, vtbl);
			vtbl->new_volume = 0; /* clear the flag */
		}
		
		DUMP_VOLINFO(ft_t_noise, &entry[VTBL_DESC], vtbl);
		entry += VTBL_SIZE;
	}
	memset(entry, 0, FT_SEGMENT_SIZE - zft_eom_vtbl->count * VTBL_SIZE);
	TRACE_EXIT;
}

/*  write volume table to tape. Calls zft_create_volume_headers()
 */
int zft_update_volume_table(unsigned int segment)
{
	int result = 0;
	__u8 *verify_buf = NULL;
	TRACE_FUN(ft_t_flow);

	TRACE_CATCH(result = ftape_read_segment(ft_first_data_segment, 
						zft_deblock_buf,
						FT_RD_SINGLE),);
	zft_create_volume_headers(zft_deblock_buf);
	TRACE(ft_t_noise, "writing volume table segment %d", segment);
	if (zft_vmalloc_once(&verify_buf, FT_SEGMENT_SIZE) == 0) {
		TRACE_CATCH(zft_verify_write_segments(segment, 
						      zft_deblock_buf, result,
						      verify_buf),
			    zft_vfree(&verify_buf, FT_SEGMENT_SIZE));
		zft_vfree(&verify_buf, FT_SEGMENT_SIZE);
	} else {
		TRACE_CATCH(ftape_write_segment(segment, zft_deblock_buf, 
						FT_WR_SINGLE),);
	}
	TRACE_EXIT 0;
}

/* non zftape volumes are handled in raw mode. Thus we need to
 * calculate the raw amount of data contained in those segments.  
 */
static void extract_alien_volume(__u8 *entry, zft_volinfo *vtbl)
{
	TRACE_FUN(ft_t_flow);

	vtbl->size  = (zft_calc_tape_pos(zft_last_vtbl->end_seg+1) -
		       zft_calc_tape_pos(zft_last_vtbl->start_seg));
	vtbl->use_compression = 0;
	vtbl->qic113 = zft_qic113;
	if (vtbl->qic113) {
		TRACE(ft_t_noise, 
		      "Fake alien volume's size from " LL_X " to " LL_X, 
		      LL(GET8(entry, VTBL_DATA_SIZE)), LL(vtbl->size));
	} else {
		TRACE(ft_t_noise,
		      "Fake alien volume's size from %d to " LL_X, 
		      (int)GET4(entry, VTBL_DATA_SIZE), LL(vtbl->size));
	}
	TRACE_EXIT;
}


/* extract an zftape specific volume
 */
static void extract_zft_volume(__u8 *entry, zft_volinfo *vtbl)
{
	TRACE_FUN(ft_t_flow);

	if (vtbl->qic113) {
		vtbl->size = GET8(entry, VTBL_DATA_SIZE);
		vtbl->use_compression = 
			(entry[VTBL_CMPR] & VTBL_CMPR_USED) != 0; 
	} else {
		vtbl->size = GET4(entry, VTBL_DATA_SIZE);
		if (entry[VTBL_K_CMPR] & VTBL_CMPR_UNREG) {
			vtbl->use_compression = 
				(entry[VTBL_K_CMPR] & VTBL_CMPR_USED) != 0;
		} else if (entry[VTBL_CMPR] & VTBL_CMPR_UNREG) {
			vtbl->use_compression = 
				(entry[VTBL_CMPR] & VTBL_CMPR_USED) != 0; 
		} else {
			TRACE(ft_t_warn, "Geeh! There is something wrong:\n"
			      KERN_INFO "QIC compression (Rev = K): %x\n"
			      KERN_INFO "QIC compression (Rev > K): %x",
			      entry[VTBL_K_CMPR], entry[VTBL_CMPR]);
		}
	}
	TRACE_EXIT;
}

/* extract the volume table from buffer. "buffer" must already contain
 * the vtbl-segment 
 */
int zft_extract_volume_headers(__u8 *buffer)
{                            
        __u8 *entry;
	TRACE_FUN(ft_t_flow);
	
	zft_init_vtbl();
	entry = buffer;
#ifdef ZFT_CMAP_HACK
	if ((strncmp(&entry[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG,
		     strlen(ZFTAPE_SIG)) == 0) &&
	    entry[VTBL_EXT+EXT_ZFTAPE_CMAP] != 0) {
		TRACE(ft_t_noise, "ignoring cmap volume");
		entry += VTBL_SIZE;