diff options
Diffstat (limited to 'drivers/char/ftape/compressor/zftape-compress.c')
| -rw-r--r-- | drivers/char/ftape/compressor/zftape-compress.c | 1203 |
1 files changed, 0 insertions, 1203 deletions
diff --git a/drivers/char/ftape/compressor/zftape-compress.c b/drivers/char/ftape/compressor/zftape-compress.c deleted file mode 100644 index 65ffc0be3df..00000000000 --- a/drivers/char/ftape/compressor/zftape-compress.c +++ /dev/null @@ -1,1203 +0,0 @@ -/* - * Copyright (C) 1994-1997 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. - - * - * This file implements a "generic" interface between the * - * zftape-driver and a compression-algorithm. The * - * compression-algorithm currently used is a LZ77. I use the * - * implementation lzrw3 by Ross N. Williams (Renaissance * - * Software). The compression program itself is in the file - * lzrw3.c * and lzrw3.h. To adopt another compression algorithm - * the functions * zft_compress() and zft_uncompress() must be - * changed * appropriately. See below. - */ - -#include <linux/errno.h> -#include <linux/mm.h> -#include <linux/module.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 "../compressor/zftape-compress.h" -#include "../zftape/zftape-vtbl.h" -#include "../compressor/lzrw3.h" - -/* - * global variables - */ - -/* I handle the allocation of this buffer as a special case, because - * it's size varies depending on the tape length inserted. - */ - -/* local variables - */ -static void *zftc_wrk_mem = NULL; -static __u8 *zftc_buf = NULL; -static void *zftc_scratch_buf = NULL; - -/* compression statistics - */ -static unsigned int zftc_wr_uncompressed = 0; -static unsigned int zftc_wr_compressed = 0; -static unsigned int zftc_rd_uncompressed = 0; -static unsigned int zftc_rd_compressed = 0; - -/* forward */ -static int zftc_write(int *write_cnt, - __u8 *dst_buf, const int seg_sz, - const __u8 __user *src_buf, const int req_len, - const zft_position *pos, const zft_volinfo *volume); -static int zftc_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); -static int zftc_seek(unsigned int new_block_pos, - zft_position *pos, const zft_volinfo *volume, - __u8 *buffer); -static void zftc_lock (void); -static void zftc_reset (void); -static void zftc_cleanup(void); -static void zftc_stats (void); - -/* compressed segment. This conforms to QIC-80-MC, Revision K. - * - * Rev. K applies to tapes with `fixed length format' which is - * indicated by format code 2,3 and 5. See below for format code 4 and 6 - * - * 2 bytes: offset of compression segment structure - * 29k > offset >= 29k-18: data from previous segment ens in this - * segment and no compressed block starts - * in this segment - * offset == 0: data from previous segment occupies entire - * segment and continues in next segment - * n bytes: remainder from previous segment - * - * Rev. K: - * 4 bytes: 4 bytes: files set byte offset - * Post Rev. K and QIC-3020/3020: - * 8 bytes: 8 bytes: files set byte offset - * 2 bytes: byte count N (amount of data following) - * bit 15 is set if data is compressed, bit 15 is not - * set if data is uncompressed - * N bytes: data (as much as specified in the byte count) - * 2 bytes: byte count N_1 of next cluster - * N_1 bytes: data of next cluset - * 2 bytes: byte count N_2 of next cluster - * N_2 bytes: ... - * - * Note that the `N' byte count accounts only for the bytes that in the - * current segment if the cluster spans to the next segment. - */ - -typedef struct -{ - int cmpr_pos; /* actual position in compression buffer */ - int cmpr_sz; /* what is left in the compression buffer - * when copying the compressed data to the - * deblock buffer - */ - unsigned int first_block; /* location of header information in - * this segment - */ - unsigned int count; /* amount of data of current block - * contained in current segment - */ - unsigned int offset; /* offset in current segment */ - unsigned int spans:1; /* might continue in next segment */ - unsigned int uncmpr; /* 0x8000 if this block contains - * uncompressed data - */ - __s64 foffs; /* file set byte offset, same as in - * compression map segment - */ -} cmpr_info; - -static cmpr_info cseg; /* static data. Must be kept uptodate and shared by - * read, write and seek functions - */ - -#define DUMP_CMPR_INFO(level, msg, info) \ - TRACE(level, msg "\n" \ - KERN_INFO "cmpr_pos : %d\n" \ - KERN_INFO "cmpr_sz : %d\n" \ - KERN_INFO "first_block: %d\n" \ - KERN_INFO "count : %d\n" \ - KERN_INFO "offset : %d\n" \ - KERN_INFO "spans : %d\n" \ - KERN_INFO "uncmpr : 0x%04x\n" \ - KERN_INFO "foffs : " LL_X, \ - (info)->cmpr_pos, (info)->cmpr_sz, (info)->first_block, \ - (info)->count, (info)->offset, (info)->spans == 1, \ - (info)->uncmpr, LL((info)->foffs)) - -/* dispatch compression segment info, return error code - * - * afterwards, cseg->offset points to start of data of the NEXT - * compressed block, and cseg->count contains the amount of data - * left in the actual compressed block. cseg->spans is set to 1 if - * the block is continued in the following segment. Otherwise it is - * set to 0. - */ -static int get_cseg (cmpr_info *cinfo, const __u8 *buff, - const unsigned int seg_sz, - const zft_volinfo *volume) -{ - TRACE_FUN(ft_t_flow); - - cinfo->first_block = GET2(buff, 0); - if (cinfo->first_block == 0) { /* data spans to next segment */ - cinfo->count = seg_sz - sizeof(__u16); - cinfo->offset = seg_sz; - cinfo->spans = 1; - } else { /* cluster definetely ends in this segment */ - if (cinfo->first_block > seg_sz) { - /* data corrupted */ - TRACE_ABORT(-EIO, ft_t_err, "corrupted data:\n" - KERN_INFO "segment size: %d\n" - KERN_INFO "first block : %d", - seg_sz, cinfo->first_block); - } - cinfo->count = cinfo->first_block - sizeof(__u16); - cinfo->offset = cinfo->first_block; - cinfo->spans = 0; - } - /* now get the offset the first block should have in the - * uncompressed data stream. - * - * For this magic `18' refer to CRF-3 standard or QIC-80MC, - * Rev. K. - */ - if ((seg_sz - cinfo->offset) > 18) { - if (volume->qic113) { /* > revision K */ - TRACE(ft_t_data_flow, "New QIC-113 compliance"); - cinfo->foffs = GET8(buff, cinfo->offset); - cinfo->offset += sizeof(__s64); - } else { - TRACE(/* ft_t_data_flow */ ft_t_noise, "pre QIC-113 version"); - cinfo->foffs = (__s64)GET4(buff, cinfo->offset); - cinfo->offset += sizeof(__u32); - } - } - if (cinfo->foffs > volume->size) { - TRACE_ABORT(-EIO, ft_t_err, "Inconsistency:\n" - KERN_INFO "offset in current volume: %d\n" - KERN_INFO "size of current volume : %d", - (int)(cinfo->foffs>>10), (int)(volume->size>>10)); - } - if (cinfo->cmpr_pos + cinfo->count > volume->blk_sz) { - TRACE_ABORT(-EIO, ft_t_err, "Inconsistency:\n" - KERN_INFO "block size : %d\n" - KERN_INFO "data record: %d", - volume->blk_sz, cinfo->cmpr_pos + cinfo->count); - } - DUMP_CMPR_INFO(ft_t_noise /* ft_t_any */, "", cinfo); - TRACE_EXIT 0; -} - -/* This one is called, when a new cluster starts in same segment. - * - * Note: if this is the first cluster in the current segment, we must - * not check whether there are more than 18 bytes available because - * this have already been done in get_cseg() and there may be less - * than 18 bytes available due to header information. - * - */ -static void get_next_cluster(cmpr_info *cluster, const __u8 *buff, - const int seg_sz, const int finish) -{ - TRACE_FUN(ft_t_flow); - - if (seg_sz - cluster->offset > 18 || cluster->foffs != 0) { - cluster->count = GET2(buff, cluster->offset); - cluster->uncmpr = cluster->count & 0x8000; - cluster->count -= cluster->uncmpr; - cluster->offset += sizeof(__u16); - cluster->foffs = 0; - if ((cluster->offset + cluster->count) < seg_sz) { - cluster->spans = 0; - } else if (cluster->offset + cluster->count == seg_sz) { - cluster->spans = !finish; - } else { - /* either an error or a volume written by an - * old version. If this is a data error, then we'll - * catch it later. - */ - TRACE(ft_t_data_flow, "Either error or old volume"); - cluster->spans = 1; - cluster->count = seg_sz - cluster->offset; - } - } else { - cluster->count = 0; - cluster->spans = 0; - cluster->foffs = 0; - } - DUMP_CMPR_INFO(ft_t_noise /* ft_t_any */ , "", cluster); - TRACE_EXIT; -} - -static void zftc_lock(void) -{ -} - -/* this function is needed for zftape_reset_position in zftape-io.c - */ -static void zftc_reset(void) -{ - TRACE_FUN(ft_t_flow); - - memset((void *)&cseg, '\0', sizeof(cseg)); - zftc_stats(); - TRACE_EXIT; -} - -static int cmpr_mem_initialized = 0; -static unsigned int alloc_blksz = 0; - -static int zft_allocate_cmpr_mem(unsigned int blksz) -{ - TRACE_FUN(ft_t_flow); - - if (cmpr_mem_initialized && blksz == alloc_blksz) { - TRACE_EXIT 0; - } - TRACE_CATCH(zft_vmalloc_once(&zftc_wrk_mem, CMPR_WRK_MEM_SIZE), - zftc_cleanup()); - TRACE_CATCH(zft_vmalloc_always(&zftc_buf, blksz + CMPR_OVERRUN), - zftc_cleanup()); - alloc_blksz = blksz; - TRACE_CATCH(zft_vmalloc_always(&zftc_scratch_buf, blksz+CMPR_OVERRUN), - zftc_cleanup()); - cmpr_mem_initialized = 1; - TRACE_EXIT 0; -} - -static void zftc_cleanup(void) -{ - TRACE_FUN(ft_t_flow); - - zft_vfree(&zftc_wrk_mem, CMPR_WRK_MEM_SIZE); - zft_vfree(&zftc_buf, alloc_blksz + CMPR_OVERRUN); - zft_vfree(&zftc_scratch_buf, alloc_blksz + CMPR_OVERRUN); - cmpr_mem_initialized = alloc_blksz = 0; - TRACE_EXIT; -} - -/***************************************************************************** - * * - * The following two functions "ftape_compress()" and * - * "ftape_uncompress()" are the interface to the actual compression * - * algorithm (i.e. they are calling the "compress()" function from * - * the lzrw3 package for now). These routines could quite easily be * - * changed to adopt another compression algorithm instead of lzrw3, * - * which currently is used. * - * * - *****************************************************************************/ - -/* called by zft_compress_write() to perform the compression. Must - * return the size of the compressed data. - * - * NOTE: The size of the compressed data should not exceed the size of - * the uncompressed data. Most compression algorithms have means - * to store data unchanged if the "compressed" data amount would - * exceed the original one. Mostly this is done by storing some - * flag-bytes in front of the compressed data to indicate if it - * is compressed or not. Thus the worst compression result - * length is the original length plus those flag-bytes. - * - * We don't want that, as the QIC-80 standard provides a means - * of marking uncompressed blocks by simply setting bit 15 of - * the compressed block's length. Thus a compessed block can - * have at most a length of 2^15-1 bytes. The QIC-80 standard - * restricts the block-length even further, allowing only 29k - - * 6 bytes. - * - * Currently, the maximum blocksize used by zftape is 28k. - * - * In short: don't exceed the length of the input-package, set - * bit 15 of the compressed size to 1 if you have copied data - * instead of compressing it. - */ -static int zft_compress(__u8 *in_buffer, unsigned int in_sz, __u8 *out_buffer) -{ - __s32 compressed_sz; - TRACE_FUN(ft_t_flow); - - - lzrw3_compress(COMPRESS_ACTION_COMPRESS, zftc_wrk_mem, - in_buffer, in_sz, out_buffer, &compressed_sz); - if (TRACE_LEVEL >= ft_t_info) { - /* the compiler will optimize this away when - * compiled with NO_TRACE_AT_ALL option - */ - TRACE(ft_t_data_flow, "\n" - KERN_INFO "before compression: %d bytes\n" - KERN_INFO "after compresison : %d bytes", - in_sz, - (int)(compressed_sz < 0 - ? -compressed_sz : compressed_sz)); - /* for statistical purposes - */ - zftc_wr_compressed += (compressed_sz < 0 - ? -compressed_sz : compressed_sz); - zftc_wr_uncompressed += in_sz; - } - TRACE_EXIT (int)compressed_sz; -} - -/* called by zft_compress_read() to decompress the data. Must - * return the size of the decompressed data for sanity checks - * (compared with zft_blk_sz) - * - * NOTE: Read the note for zft_compress() above! If bit 15 of the - * parameter in_sz is set, then the data in in_buffer isn't - * compressed, which must be handled by the un-compression - * algorithm. (I changed lzrw3 to handle this.) - * - * The parameter max_out_sz is needed to prevent buffer overruns when - * uncompressing corrupt data. - */ -static unsigned int zft_uncompress(__u8 *in_buffer, - int in_sz, - __u8 *out_buffer, - unsigned int max_out_sz) -{ - TRACE_FUN(ft_t_flow); - - lzrw3_compress(COMPRESS_ACTION_DECOMPRESS, zftc_wrk_mem, - in_buffer, (__s32)in_sz, - out_buffer, (__u32 *)&max_out_sz); - - if (TRACE_LEVEL >= ft_t_info) { - TRACE(ft_t_data_flow, "\n" - KERN_INFO "before decompression: %d bytes\n" - KERN_INFO "after decompression : %d bytes", - in_sz < 0 ? -in_sz : in_sz,(int)max_out_sz); - /* for statistical purposes - */ - zftc_rd_compressed += in_sz < 0 ? -in_sz : in_sz; - zftc_rd_uncompressed += max_out_sz; - } - TRACE_EXIT (unsigned int)max_out_sz; -} - -/* print some statistics about the efficiency of the compression to - * the kernel log - */ -static void zftc_stats(void) -{ - TRACE_FUN(ft_t_flow); - - if (TRACE_LEVEL < ft_t_info) { - TRACE_EXIT; - } - if (zftc_wr_uncompressed != 0) { - if (zftc_wr_compressed > (1<<14)) { - TRACE(ft_t_info, "compression statistics (writing):\n" - KERN_INFO " compr./uncmpr. : %3d %%", - (((zftc_wr_compressed>>10) * 100) - / (zftc_wr_uncompressed>>10))); - } else { - TRACE(ft_t_info, "compression statistics (writing):\n" - KERN_INFO " compr./uncmpr. : %3d %%", - ((zftc_wr_compressed * 100) - / zftc_wr_uncompressed)); - } - } - if (zftc_rd_uncompressed != 0) { - if (zftc_rd_compressed > (1<<14)) { - TRACE(ft_t_info, "compression statistics (reading):\n" - KERN_INFO " compr./uncmpr. : %3d %%", - (((zftc_rd_compressed>>10) * 100) - / (zftc_rd_uncompressed>>10))); - } else { - TRACE(ft_t_info, "compression statistics (reading):\n" - KERN_INFO " compr./uncmpr. : %3d %%", - ((zftc_rd_compressed * 100) - / zftc_rd_uncompressed)); - } - } - /* only print it once: */ - zftc_wr_uncompressed = - zftc_wr_compressed = - zftc_rd_uncompressed = - zftc_rd_compressed = 0; - TRACE_EXIT; -} - -/* start new compressed block - */ -static int start_new_cseg(cmpr_info *cluster, - char *dst_buf, - const zft_position *pos, - const unsigned int blk_sz, - const char *src_buf, - const int this_segs_sz, - const int qic113) -{ - int size_left; - int cp_cnt; - int buf_pos; - TRACE_FUN(ft_t_flow); - - size_left = this_segs_sz - sizeof(__u16) - cluster->cmpr_sz; - TRACE(ft_t_data_flow,"\n" - KERN_INFO "segment size : %d\n" - KERN_INFO "compressed_sz: %d\n" - KERN_INFO "size_left : %d", - this_segs_sz, cluster->cmpr_sz, size_left); - if (size_left > 18) { /* start a new cluseter */ - cp_cnt = cluster->cmpr_sz; - cluster->cmpr_sz = 0; - buf_pos = cp_cnt + sizeof(__u16); - PUT2(dst_buf, 0, buf_pos); - - if (qic113) { - __s64 foffs = pos->volume_pos; - if (cp_cnt) foffs += (__s64)blk_sz; - - TRACE(ft_t_data_flow, "new style QIC-113 header"); - PUT8(dst_buf, buf_pos, foffs); - buf_pos += sizeof(__s64); - } else { - __u32 foffs = (__u32)pos->volume_pos; - if (cp_cnt) foffs += (__u32)blk_sz; - - TRACE(ft_t_data_flow, "old style QIC-80MC header"); - PUT4(dst_buf, buf_pos, foffs); - buf_pos += sizeof(__u32); - } - } else if (size_left >= 0) { - cp_cnt = cluster->cmpr_sz; - cluster->cmpr_sz = 0; - buf_pos = cp_cnt + sizeof(__u16); - PUT2(dst_buf, 0, buf_pos); - /* zero unused part of segment. */ - memset(dst_buf + buf_pos, '\0', size_left); - buf_pos = this_segs_sz; - } else { /* need entire segment and more space */ - PUT2(dst_buf, 0, 0); - cp_cnt = this_segs_sz - sizeof(__u16); - cluster->cmpr_sz -= cp_cnt; - buf_pos = this_segs_sz; - } - memcpy(dst_buf + sizeof(__u16), src_buf + cluster->cmpr_pos, cp_cnt); - cluster->cmpr_pos += cp_cnt; - TRACE_EXIT buf_pos; -} - -/* return-value: the number of bytes removed from the user-buffer - * `src_buf' or error code - * - * int *write_cnt : how much actually has been moved to the - * dst_buf. Need not be initialized when - * function returns with an error code - * (negativ return value) - * __u8 *dst_buf : kernel space buffer where the has to be - * copied to. The contents of this buffers - * goes to a specific segment. - * const int seg_sz : the size of the segment dst_buf will be - * copied to. - * const zft_position *pos : struct containing the coordinates in - * the current volume (byte position, - * segment id of current segment etc) - * const zft_volinfo *volume: information about the current volume, - * size etc. - * const __u8 *src_buf : user space buffer that contains the - * data the user wants to be written to - * tape. - * const int req_len : the amount of data the user wants to be - * written to tape. - */ -static int zftc_write(int *write_cnt, - __u8 *dst_buf, const int seg_sz, - const __u8 __user *src_buf, const int req_len, - const zft_position *pos, const zft_volinfo *volume) -{ - int req_len_left = req_len; - int result; - int len_left; - int buf_pos_write = pos->seg_byte_pos; - TRACE_FUN(ft_t_flow); - - /* Note: we do not unlock the module because - * there are some values cached in that `cseg' variable. We - * don't don't want to use this information when being - * unloaded by kerneld even when the tape is full or when we - * cannot allocate enough memory. - */ - if (pos->tape_pos > (volume->size-volume->blk_sz-ZFT_CMPR_OVERHEAD)) { - TRACE_EXIT -ENOSPC; - } - if (zft_allocate_cmpr_mem(volume->blk_sz) < 0) { - /* should we unlock the module? But it shouldn't - * be locked anyway ... - */ - TRACE_EXIT -ENOMEM; - } - if (buf_pos_write == 0) { /* fill a new segment */ - *write_cnt = buf_pos_write = start_new_cseg(&cseg, - dst_buf, - pos, - volume->blk_sz, - zftc_buf, - seg_sz, - volume->qic113); - if (cseg.cmpr_sz == 0 && cseg.cmpr_pos != 0) { - req_len_left -= result = volume->blk_sz; - cseg.cmpr_pos = 0; - } else { - result = 0; - } - } else { - *write_cnt = result = 0; - } - - len_left = seg_sz - buf_pos_write; - while ((req_len_left > 0) && (len_left > 18)) { - /* now we have some size left for a new compressed - * block. We know, that the compression buffer is - * empty (else there wouldn't be any space left). - */ - if (copy_from_user(zftc_scratch_buf, src_buf + result, - volume->blk_sz) != 0) { - TRACE_EXIT -EFAULT; - } - req_len_left -= volume->blk_sz; - cseg.cmpr_sz = zft_compress(zftc_scratch_buf, volume->blk_sz, - zftc_buf); - if (cseg.cmpr_sz < 0) { - cseg.uncmpr = 0x8000; - cseg.cmpr_sz = -cseg.cmpr_sz; - } else { - cseg.uncmpr = 0; - } - /* increment "result" iff we copied the entire - * compressed block to the zft_deblock_buf - */ - len_left -= sizeof(__u16); - if (len_left >= cseg.cmpr_sz) { - len_left -= cseg.count = cseg.cmpr_sz; - cseg.cmpr_pos = cseg.cmpr_sz = 0; - result += volume->blk_sz; - } else { - cseg.cmpr_sz -= - cseg.cmpr_pos = - cseg.count = len_left; - len_left = 0; - } - PUT2(dst_buf, buf_pos_write, cseg.uncmpr | cseg.count); - buf_pos_write += sizeof(__u16); - memcpy(dst_buf + buf_pos_write, zftc_buf, cseg.count); - buf_pos_write += cseg.count; - *write_cnt += cseg.count + sizeof(__u16); - FT_SIGNAL_EXIT(_DONT_BLOCK); - } - /* erase the remainder of the segment if less than 18 bytes - * left (18 bytes is due to the QIC-80 standard) - */ - if (len_left <= 18) { - memset(dst_buf + buf_pos_write, '\0', len_left); - (*write_cnt) += len_left; - } - TRACE(ft_t_data_flow, "returning %d", result); - TRACE_EXIT result; -} - -/* 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. - * - * 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 from _ftape_read() - * int buf_len_read : copy of buf_len_rd from _ftape_read() - * char *zft_deblock_buf: zft_deblock_buf - * unsigned short blk_sz: the block size valid for this volume, may differ - * from zft_blk_sz. - * int finish: if != 0 means that this is the last segment belonging - * to this volume - * returns the amount of data actually copied to the user-buffer - * - * to_do MUST NOT SHRINK except to indicate an EOF. In this case *to_do has to - * be set to 0 - */ -static int zftc_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) -{ - int uncompressed_sz; - int result = 0; - int remaining = to_do; - TRACE_FUN(ft_t_flow); - - TRACE_CATCH(zft_allocate_cmpr_mem(volume->blk_sz),); - if (pos->seg_byte_pos == 0) { - /* new segment just read - */ - TRACE_CATCH(get_cseg(&cseg, src_buf, seg_sz, volume), - *read_cnt = 0); - memcpy(zftc_buf + cseg.cmpr_pos, src_buf + sizeof(__u16), - cseg.count); - cseg.cmpr_pos += cseg.count; - *read_cnt = cseg.offset; - DUMP_CMPR_INFO(ft_t_noise /* ft_t_any */, "", &cseg); - } else { - *read_cnt = 0; - } - /* loop and uncompress until user buffer full or - * deblock-buffer empty - */ - TRACE(ft_t_data_flow, "compressed_sz: %d, compos : %d, *read_cnt: %d", - cseg.cmpr_sz, cseg.cmpr_pos, *read_cnt); - while ((cseg.spans == 0) && (remaining > 0)) { - if (cseg.cmpr_pos != 0) { /* cmpr buf is not empty */ - uncompressed_sz = - zft_uncompress(zftc_buf, - cseg.uncmpr == 0x8000 ? - -cseg.cmpr_pos : cseg.cmpr_pos, - zftc_scratch_buf, - volume->blk_sz); - if (uncompressed_sz != volume->blk_sz) { - *read_cnt = 0; - TRACE_ABORT(-EIO, ft_t_warn, - "Uncompressed blk (%d) != blk size (%d)", - uncompressed_sz, volume->blk_sz); - } - if (copy_to_user(dst_buf + result, - zftc_scratch_buf, - uncompressed_sz) != 0 ) { - TRACE_EXIT -EFAULT; - } - remaining -= uncompressed_sz; - result += uncompressed_sz; - cseg.cmpr_pos = 0; - } - if (remaining > 0) { - get_next_cluster(&cseg, src_buf, seg_sz, - volume->end_seg == pos->seg_pos); - if (cseg.count != 0) { - memcpy(zftc_buf, src_buf + cseg.offset, - cseg.count); - cseg.cmpr_pos = cseg.count; - cseg.offset += cseg.count; - *read_cnt += cseg.count + sizeof(__u16); - } else { - remaining = 0; - } - } - TRACE(ft_t_data_flow, "\n" - KERN_INFO "compressed_sz: %d\n" - KERN_INFO "compos : %d\n" - KERN_INFO "*read_cnt : %d", - cseg.cmpr_sz, cseg.cmpr_pos, *read_cnt); - } - if (seg_sz - cseg.offset <= 18) { - *read_cnt += seg_sz - cseg.offset; - TRACE(ft_t_data_flow, "expanding read cnt to: %d", *read_cnt); - } - TRACE(ft_t_data_flow, "\n" - KERN_INFO "segment size : %d\n" - KERN_INFO "read count : %d\n" - KERN_INFO "buf_pos_read : %d\n" - KERN_INFO "remaining : %d", - seg_sz, *read_cnt, pos->seg_byte_pos, - seg_sz - *read_cnt - pos->seg_byte_pos); - TRACE(ft_t_data_flow, "returning: %d", result); - TRACE_EXIT result; -} - -/* seeks to the new data-position. Reads sometimes a segment. - * - * start_seg and end_seg give the boundaries of the current volume - * blk_sz is the blk_sz of the current volume as stored in the - * volume label - * - * We don't allow blocksizes less than 1024 bytes, therefore we don't need - * a 64 bit argument for new_block_pos. - */ - -static int seek_in_segment(const unsigned int to_do, cmpr_info *c_info, - const char *src_buf, const int seg_sz, - const int seg_pos, const zft_volinfo *volume); -static int slow_seek_forward_until_error(const unsigned int distance, - cmpr_info *c_info, zft_position *pos, - const zft_volinfo *volume, __u8 *buf); -static int search_valid_segment(unsigned int segment, - const unsigned int end_seg, - const unsigned int max_foffs, - zft_position *pos, cmpr_info *c_info, - const zft_volinfo *volume, __u8 *buf); -static int slow_seek_forward(unsigned int dest, cmpr_info *c_info, - zft_position *pos, const zft_volinfo *volume, - __u8 *buf); -static int compute_seg_pos(unsigned int dest, zft_position *pos, - const zft_volinfo *volume); - -#define ZFT_SLOW_SEEK_THRESHOLD 10 /* segments */ -#define ZFT_FAST_SEEK_MAX_TRIALS 10 /* times */ -#define ZFT_FAST_SEEK_BACKUP 10 /* segments */ - -static int zftc_seek(unsigned int new_block_pos, - zft_position *pos, const zft_volinfo *volume, __u8 *buf) -{ - unsigned int dest; - int limit; - int distance; - int result = 0; - int seg_dist; - int new_seg; - int old_seg = 0; - int fast_seek_trials = 0; - TRACE_FUN(ft_t_flow); - - if (new_block_pos == 0) { - pos->seg_pos = volume->start_seg; - pos->seg_byte_pos = 0; - pos->volume_pos = 0; - zftc_reset(); - TRACE_EXIT 0; - } - dest = new_block_pos * (volume->blk_sz >> 10); - distance = dest - (pos->volume_pos >> 10); - while (distance != 0) { - seg_dist = compute_seg_pos(dest, pos, volume); - TRACE(ft_t_noise, "\n" - KERN_INFO "seg_dist: %d\n" - KERN_INFO "distance: %d\n" - KERN_INFO "dest : %d\n" - KERN_INFO "vpos : %d\n" - KERN_INFO "seg_pos : %d\n" - KERN_INFO "trials : %d", - seg_dist, distance, dest, - (unsigned int)(pos->volume_pos>>10), pos->seg_pos, - fast_seek_trials); - if (distance > 0) { - if (seg_dist < 0) { - TRACE(ft_t_bug, "BUG: distance %d > 0, " - "segment difference %d < 0", - distance, seg_dist); - result = -EIO; - break; - } - new_seg = pos->seg_pos + seg_dist; - if (new_seg > volume->end_seg) { - new_seg = volume->end_seg; - } - if (old_seg == new_seg || /* loop */ - seg_dist <= ZFT_SLOW_SEEK_THRESHOLD || - fast_seek_trials >= ZFT_FAST_SEEK_MAX_TRIALS) { - TRACE(ft_t_noise, "starting slow seek:\n" - KERN_INFO "fast seek failed too often: %s\n" - KERN_INFO "near target position : %s\n" - KERN_INFO "looping between two segs : %s", - (fast_seek_trials >= - ZFT_FAST_SEEK_MAX_TRIALS) - ? "yes" : "no", - (seg_dist <= ZFT_SLOW_SEEK_THRESHOLD) - ? "yes" : "no", - (old_seg == new_seg) - ? "yes" : "no"); - result = slow_seek_forward(dest, &cseg, - pos, volume, buf); - break; - } - old_seg = new_seg; - limit = volume->end_seg; - fast_seek_trials ++; - for (;;) { - result = search_valid_segment(new_seg, limit, - volume->size, - pos, &cseg, - volume, buf); - if (result == 0 || result == -EINTR) { - break; - } - if (new_seg == volume->start_seg) { - result = -EIO; /* set errror - * condition - */ - break; - } - limit = new_seg; - new_seg -= ZFT_FAST_SEEK_BACKUP; - if (new_seg < volume->start_seg) { - new_seg = volume->start_seg; - } - } - if (result < 0) { - TRACE(ft_t_warn, - "Couldn't find a readable segment"); - break; - } - } else /* if (distance < 0) */ { - if (seg_dist > 0) { - TRACE(ft_t_bug, "BUG: distance %d < 0, " - "segment difference %d >0", - distance, seg_dist); - result = -EIO; - break; - } - new_seg = pos->seg_pos + seg_dist; - if (fast_seek_trials > 0 && seg_dist == 0) { - /* this avoids sticking to the same - * segment all the time. On the other hand: - * if we got here for the first time, and the - * deblock_buffer still contains a valid - * segment, then there is no need to skip to - * the previous segment if the desired position - * is inside this segment. - */ - new_seg --; - } - if (new_seg < volume->start_seg) { - new_seg = volume->start_seg; - } - limit = pos->seg_pos; - fast_seek_trials ++; - for (;;) { - result = search_valid_segment(new_seg, limit, - pos->volume_pos, - pos, &cseg, - volume, buf); - if (result == 0 || result == -EINTR) { - break; - } - if (new_seg == volume->start_seg) { - result = -EIO; /* set errror - * condition - */ - break; - } - limit = new_seg; - new_seg -= ZFT_FAST_SEEK_BACKUP; - if (new_seg < volume->start_seg) { - new_seg = volume->start_seg; - } - } - if (result < 0) { - TRACE(ft_t_warn, - "Couldn't find a readable segment"); - break; - } - } - distance = dest - (pos->volume_pos >> 10); - } - TRACE_EXIT result; -} - - -/* advance inside the given segment at most to_do bytes. - * of kilobytes moved - */ - -static int seek_in_segment(const unsigned int to_do, - cmpr_info *c_info, - const char *src_buf, - const int seg_sz, - const int seg_pos, - const zft_volinfo *volume) -{ - int result = 0; - int blk_sz = volume->blk_sz >> 10; - int remaining = to_do; - TRACE_FUN(ft_t_flow); - - if (c_info->offset == 0) { - /* new segment just read - */ - TRACE_CATCH(get_cseg(c_info, src_buf, seg_sz, volume),); - c_info->cmpr_pos += c_info->count; - DUMP_CMPR_INFO(ft_t_noise, "", c_info); - } - /* loop and uncompress until user buffer full or - * deblock-buffer empty - */ - TRACE(ft_t_noise, "compressed_sz: %d, compos : %d", - c_info->cmpr_sz, c_info->cmpr_pos); - while (c_info->spans == 0 && remaining > 0) { - if (c_info->cmpr_pos != 0) { /* cmpr buf is not empty */ - result += blk_sz; - remaining -= blk_sz; - c_info->cmpr_pos = 0; - } - if (remaining > 0) { - get_next_cluster(c_info, src_buf, seg_sz, - volume->end_seg == seg_pos); - if (c_info->count != 0) { - c_info->cmpr_pos = c_info->count; - c_info->offset += c_info->count; - } else { - break; - } - } - /* Allow escape from this loop on signal! - */ - FT_SIGNAL_EXIT(_DONT_BLOCK); - DUMP_CMPR_INFO(ft_t_noise, "", c_info); - TRACE(ft_t_noise, "to_do: %d", remaining); - } - if (seg_sz - c_info->offset <= 18) { - c_info->offset = seg_sz; - } - TRACE(ft_t_noise, "\n" - KERN_INFO "segment size : %d\n" - KERN_INFO "buf_pos_read : %d\n" - KERN_INFO "remaining : %d", - seg_sz, c_info->offset, - seg_sz - c_info->offset); - TRACE_EXIT result; -} - -static int slow_seek_forward_until_error(const unsigned int distance, - cmpr_info *c_info, - zft_position *pos, - const zft_volinfo *volume, - __u8 *buf) -{ - unsigned int remaining = distance; - int seg_sz; - int seg_pos; - int result; - TRACE_FUN(ft_t_flow); - - seg_pos = pos->seg_pos; - do { - TRACE_CATCH(seg_sz = zft_fetch_segment(seg_pos, buf, - FT_RD_AHEAD),); - /* now we have the contents of the actual segment in - * the deblock buffer - */ - TRACE_CATCH(result = seek_in_segment(remaining, c_info, buf, - seg_sz, seg_pos,volume),); - remaining -= result; - pos->volume_pos += result<<10; - pos->seg_pos = seg_pos; - pos->seg_byte_pos = c_info->offset; - seg_pos ++; - if (seg_pos <= volume->end_seg && c_info->offset == seg_sz) { - pos->seg_pos ++; - pos->seg_byte_pos = 0; - c_info->offset = 0; - } - /* Allow escape from this loop on signal! - */ - FT_SIGNAL_EXIT(_DONT_BLOCK); - TRACE(ft_t_noise, "\n" - KERN_INFO "remaining: %d\n" - KERN_INFO "seg_pos: %d\n" - KERN_INFO "end_seg: %d\n" - KERN_INFO "result: %d", - remaining, seg_pos, volume->end_seg, result); - } while (remaining > 0 && seg_pos <= volume->end_seg); - TRACE_EXIT 0; -} - -/* return segment id of next segment containing valid data, -EIO otherwise - */ -static int search_valid_segment(unsigned int segment, - const unsigned int end_seg, - const unsigned int max_foffs, - zft_position *pos, - cmpr_info *c_info, - const zft_volinfo *volume, - __u8 *buf) -{ - cmpr_info tmp_info; - int seg_sz; - TRACE_FUN(ft_t_flow); - - memset(&tmp_info, 0, sizeof(cmpr_info)); - while (segment <= end_seg) { - FT_SIGNAL_EXIT(_DONT_BLOCK); - TRACE(ft_t_noise, - "Searching readable segment between %d and %d", - segment, end_seg); - seg_sz = zft_fetch_segment(segment, buf, FT_RD_AHEAD); - if ((seg_sz > 0) && - (get_cseg (&tmp_info, buf, seg_sz, volume) >= 0) && - (tmp_info.foffs != 0 || segment == volume->start_seg)) { - if ((tmp_info.foffs>>10) > max_foffs) { - TRACE_ABORT(-EIO, ft_t_noise, "\n" - KERN_INFO "cseg.foff: %d\n" - KERN_INFO "dest : %d", - (int)(tmp_info.foffs >> 10), - max_foffs); - } - DUMP_CMPR_INFO(ft_t_noise, "", &tmp_info); - *c_info = tmp_info; - pos->seg_pos = segment; - pos->volume_pos = c_info->foffs; - pos->seg_byte_pos = c_info->offset; - TRACE(ft_t_noise, "found segment at %d", segment); - TRACE_EXIT 0; - } - segment++; - } - TRACE_EXIT -EIO; -} - -static int slow_seek_forward(unsigned int dest, - cmpr_info *c_info, - zft_position *pos, - const zft_volinfo *volume, - __u8 *buf) -{ - unsigned int distance; - int result = 0; - TRACE_FUN(ft_t_flow); - - distance = dest - (pos->volume_pos >> 10); - while ((distance > 0) && - (result = slow_seek_forward_until_error(distance, - c_info, - pos, - volume, - buf)) < 0) { - if (result == -EINTR) { - break; - } - TRACE(ft_t_noise, "seg_pos: %d", pos->seg_pos); - /* the failing segment is either pos->seg_pos or - * pos->seg_pos + 1. There is no need to further try - * that segment, because ftape_read_segment() already - * has tried very much to read it. So we start with - * following segment, which is pos->seg_pos + 1 - */ - if(search_valid_segment(pos->seg_pos+1, volume->end_seg, dest, - pos, c_info, - volume, buf) < 0) { - TRACE(ft_t_noise, "search_valid_segment() failed"); - result = -EIO; - break; - } - distance = dest - (pos->volume_pos >> 10); - result = 0; - TRACE(ft_t_noise, "segment: %d", pos->seg_pos); - /* found valid segment, retry the seek */ - } - TRACE_EXIT result; -} - -static int compute_seg_pos(const unsigned int dest, - zft_position *pos, - const zft_volinfo *volume) -{ - int segment; - int distance = dest - (pos->volume_pos >> 10); - unsigned int raw_size; - unsigned int virt_size; - unsigned int factor; - TRACE_FUN(ft_t_flow); - - if (distance >= 0) { - raw_size = volume->end_seg - pos->seg_pos + 1; - virt_size = ((unsigned int)(volume->size>>10) - - (unsigned int)(pos->volume_pos>>10) - + FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS - 1); - virt_size /= FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS; - if (virt_size == 0 || raw_size == 0) { - TRACE_EXIT 0; - } - if (raw_size >= (1<<25)) { - factor = raw_size/(virt_size>>7); - } else { - factor = (raw_size<<7)/virt_size; - } - segment = distance/(FT_SECTORS_PER_SEGMENT-FT_ECC_SECTORS); - segment = (segment * factor)>>7; - } else { - raw_size = pos->seg_pos - volume->start_seg + 1; - virt_size = ((unsigned int)(pos->volume_pos>>10) - + FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS - 1); - virt_size /= FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS; - if (virt_size == 0 || raw_size == 0) { - TRACE_EXIT 0; - } - if (raw_size >= (1<<25)) { - factor = raw_size/(virt_size>>7); - } else { - factor = (raw_size<<7)/virt_size; - } - segment = distance/(FT_SECTORS_PER_SEGMENT-FT_ECC_SECTORS); - } - TRACE(ft_t_noise, "factor: %d/%d", factor, 1<<7); - TRACE_EXIT segment; -} - -static struct zft_cmpr_ops cmpr_ops = { - zftc_write, - zftc_read, - zftc_seek, - zftc_lock, - zftc_reset, - zftc_cleanup -}; - -int zft_compressor_init(void) -{ - TRACE_FUN(ft_t_flow); - -#ifdef MODULE - printk(KERN_INFO "zftape compressor v1.00a 970514 for " FTAPE_VERSION "\n"); - if (TRACE_LEVEL >= ft_t_info) { - printk( -KERN_INFO "(c) 1997 Claus-Justus Heine (claus@momo.math.rwth-aachen.de)\n" -KERN_INFO "Compressor for zftape (lzrw3 algorithm)\n"); - } -#else /* !MODULE */ - /* print a short no-nonsense boot message */ - printk(KERN_INFO "zftape compressor v1.00a 970514\n"); - printk(KERN_INFO "For use with " FTAPE_VERSION "\n"); -#endif /* MODULE */ - TRACE(ft_t_info, "zft_compressor_init @ 0x%p", zft_compressor_init); - TRACE(ft_t_info, "installing compressor for zftape ..."); - TRACE_CATCH(zft_cmpr_register(&cmpr_ops),); - TRACE_EXIT 0; -} - -#ifdef MODULE - -MODULE_AUTHOR( - "(c) 1996, 1997 Claus-Justus Heine (claus@momo.math.rwth-aachen.de"); -MODULE_DESCRIPTION( -"Compression routines for zftape. Uses the lzrw3 algorithm by Ross Williams"); -MODULE_LICENSE("GPL"); - -/* Called by modules package when installing the driver - */ -int init_module(void) -{ - return zft_compressor_init(); -} - -#endif /* MODULE */ |