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-rw-r--r--drivers/char/ftape/compressor/zftape-compress.c1203
1 files changed, 1203 insertions, 0 deletions
diff --git a/drivers/char/ftape/compressor/zftape-compress.c b/drivers/char/ftape/compressor/zftape-compress.c
new file mode 100644
index 00000000000..220a227e606
--- /dev/null
+++ b/drivers/char/ftape/compressor/zftape-compress.c
@@ -0,0 +1,1203 @@
+/*
+ * 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("zftape compressor v1.00a 970514\n");
+ printk("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 */