| 1 |
62 |
marcus.erl |
/* -*- linux-c -*- ------------------------------------------------------- *
|
| 2 |
|
|
*
|
| 3 |
|
|
* Copyright 2001 H. Peter Anvin - All Rights Reserved
|
| 4 |
|
|
*
|
| 5 |
|
|
* This program is free software; you can redistribute it and/or modify
|
| 6 |
|
|
* it under the terms of the GNU General Public License as published by
|
| 7 |
|
|
* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
|
| 8 |
|
|
* USA; either version 2 of the License, or (at your option) any later
|
| 9 |
|
|
* version; incorporated herein by reference.
|
| 10 |
|
|
*
|
| 11 |
|
|
* ----------------------------------------------------------------------- */
|
| 12 |
|
|
|
| 13 |
|
|
/*
|
| 14 |
|
|
* linux/fs/isofs/compress.c
|
| 15 |
|
|
*
|
| 16 |
|
|
* Transparent decompression of files on an iso9660 filesystem
|
| 17 |
|
|
*/
|
| 18 |
|
|
|
| 19 |
|
|
#include <linux/module.h>
|
| 20 |
|
|
#include <linux/init.h>
|
| 21 |
|
|
|
| 22 |
|
|
#include <linux/vmalloc.h>
|
| 23 |
|
|
#include <linux/zlib.h>
|
| 24 |
|
|
|
| 25 |
|
|
#include "isofs.h"
|
| 26 |
|
|
#include "zisofs.h"
|
| 27 |
|
|
|
| 28 |
|
|
/* This should probably be global. */
|
| 29 |
|
|
static char zisofs_sink_page[PAGE_CACHE_SIZE];
|
| 30 |
|
|
|
| 31 |
|
|
/*
|
| 32 |
|
|
* This contains the zlib memory allocation and the mutex for the
|
| 33 |
|
|
* allocation; this avoids failures at block-decompression time.
|
| 34 |
|
|
*/
|
| 35 |
|
|
static void *zisofs_zlib_workspace;
|
| 36 |
|
|
static DEFINE_MUTEX(zisofs_zlib_lock);
|
| 37 |
|
|
|
| 38 |
|
|
/*
|
| 39 |
|
|
* When decompressing, we typically obtain more than one page
|
| 40 |
|
|
* per reference. We inject the additional pages into the page
|
| 41 |
|
|
* cache as a form of readahead.
|
| 42 |
|
|
*/
|
| 43 |
|
|
static int zisofs_readpage(struct file *file, struct page *page)
|
| 44 |
|
|
{
|
| 45 |
|
|
struct inode *inode = file->f_path.dentry->d_inode;
|
| 46 |
|
|
struct address_space *mapping = inode->i_mapping;
|
| 47 |
|
|
unsigned int maxpage, xpage, fpage, blockindex;
|
| 48 |
|
|
unsigned long offset;
|
| 49 |
|
|
unsigned long blockptr, blockendptr, cstart, cend, csize;
|
| 50 |
|
|
struct buffer_head *bh, *ptrbh[2];
|
| 51 |
|
|
unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
|
| 52 |
|
|
unsigned int bufshift = ISOFS_BUFFER_BITS(inode);
|
| 53 |
|
|
unsigned long bufmask = bufsize - 1;
|
| 54 |
|
|
int err = -EIO;
|
| 55 |
|
|
int i;
|
| 56 |
|
|
unsigned int header_size = ISOFS_I(inode)->i_format_parm[0];
|
| 57 |
|
|
unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
|
| 58 |
|
|
/* unsigned long zisofs_block_size = 1UL << zisofs_block_shift; */
|
| 59 |
|
|
unsigned int zisofs_block_page_shift = zisofs_block_shift-PAGE_CACHE_SHIFT;
|
| 60 |
|
|
unsigned long zisofs_block_pages = 1UL << zisofs_block_page_shift;
|
| 61 |
|
|
unsigned long zisofs_block_page_mask = zisofs_block_pages-1;
|
| 62 |
|
|
struct page *pages[zisofs_block_pages];
|
| 63 |
|
|
unsigned long index = page->index;
|
| 64 |
|
|
int indexblocks;
|
| 65 |
|
|
|
| 66 |
|
|
/* We have already been given one page, this is the one
|
| 67 |
|
|
we must do. */
|
| 68 |
|
|
xpage = index & zisofs_block_page_mask;
|
| 69 |
|
|
pages[xpage] = page;
|
| 70 |
|
|
|
| 71 |
|
|
/* The remaining pages need to be allocated and inserted */
|
| 72 |
|
|
offset = index & ~zisofs_block_page_mask;
|
| 73 |
|
|
blockindex = offset >> zisofs_block_page_shift;
|
| 74 |
|
|
maxpage = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
|
| 75 |
|
|
maxpage = min(zisofs_block_pages, maxpage-offset);
|
| 76 |
|
|
|
| 77 |
|
|
for ( i = 0 ; i < maxpage ; i++, offset++ ) {
|
| 78 |
|
|
if ( i != xpage ) {
|
| 79 |
|
|
pages[i] = grab_cache_page_nowait(mapping, offset);
|
| 80 |
|
|
}
|
| 81 |
|
|
page = pages[i];
|
| 82 |
|
|
if ( page ) {
|
| 83 |
|
|
ClearPageError(page);
|
| 84 |
|
|
kmap(page);
|
| 85 |
|
|
}
|
| 86 |
|
|
}
|
| 87 |
|
|
|
| 88 |
|
|
/* This is the last page filled, plus one; used in case of abort. */
|
| 89 |
|
|
fpage = 0;
|
| 90 |
|
|
|
| 91 |
|
|
/* Find the pointer to this specific chunk */
|
| 92 |
|
|
/* Note: we're not using isonum_731() here because the data is known aligned */
|
| 93 |
|
|
/* Note: header_size is in 32-bit words (4 bytes) */
|
| 94 |
|
|
blockptr = (header_size + blockindex) << 2;
|
| 95 |
|
|
blockendptr = blockptr + 4;
|
| 96 |
|
|
|
| 97 |
|
|
indexblocks = ((blockptr^blockendptr) >> bufshift) ? 2 : 1;
|
| 98 |
|
|
ptrbh[0] = ptrbh[1] = NULL;
|
| 99 |
|
|
|
| 100 |
|
|
if ( isofs_get_blocks(inode, blockptr >> bufshift, ptrbh, indexblocks) != indexblocks ) {
|
| 101 |
|
|
if ( ptrbh[0] ) brelse(ptrbh[0]);
|
| 102 |
|
|
printk(KERN_DEBUG "zisofs: Null buffer on reading block table, inode = %lu, block = %lu\n",
|
| 103 |
|
|
inode->i_ino, blockptr >> bufshift);
|
| 104 |
|
|
goto eio;
|
| 105 |
|
|
}
|
| 106 |
|
|
ll_rw_block(READ, indexblocks, ptrbh);
|
| 107 |
|
|
|
| 108 |
|
|
bh = ptrbh[0];
|
| 109 |
|
|
if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
|
| 110 |
|
|
printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
|
| 111 |
|
|
inode->i_ino, blockptr >> bufshift);
|
| 112 |
|
|
if ( ptrbh[1] )
|
| 113 |
|
|
brelse(ptrbh[1]);
|
| 114 |
|
|
goto eio;
|
| 115 |
|
|
}
|
| 116 |
|
|
cstart = le32_to_cpu(*(__le32 *)(bh->b_data + (blockptr & bufmask)));
|
| 117 |
|
|
|
| 118 |
|
|
if ( indexblocks == 2 ) {
|
| 119 |
|
|
/* We just crossed a block boundary. Switch to the next block */
|
| 120 |
|
|
brelse(bh);
|
| 121 |
|
|
bh = ptrbh[1];
|
| 122 |
|
|
if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
|
| 123 |
|
|
printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
|
| 124 |
|
|
inode->i_ino, blockendptr >> bufshift);
|
| 125 |
|
|
goto eio;
|
| 126 |
|
|
}
|
| 127 |
|
|
}
|
| 128 |
|
|
cend = le32_to_cpu(*(__le32 *)(bh->b_data + (blockendptr & bufmask)));
|
| 129 |
|
|
brelse(bh);
|
| 130 |
|
|
|
| 131 |
|
|
if (cstart > cend)
|
| 132 |
|
|
goto eio;
|
| 133 |
|
|
|
| 134 |
|
|
csize = cend-cstart;
|
| 135 |
|
|
|
| 136 |
|
|
if (csize > deflateBound(1UL << zisofs_block_shift))
|
| 137 |
|
|
goto eio;
|
| 138 |
|
|
|
| 139 |
|
|
/* Now page[] contains an array of pages, any of which can be NULL,
|
| 140 |
|
|
and the locks on which we hold. We should now read the data and
|
| 141 |
|
|
release the pages. If the pages are NULL the decompressed data
|
| 142 |
|
|
for that particular page should be discarded. */
|
| 143 |
|
|
|
| 144 |
|
|
if ( csize == 0 ) {
|
| 145 |
|
|
/* This data block is empty. */
|
| 146 |
|
|
|
| 147 |
|
|
for ( fpage = 0 ; fpage < maxpage ; fpage++ ) {
|
| 148 |
|
|
if ( (page = pages[fpage]) != NULL ) {
|
| 149 |
|
|
memset(page_address(page), 0, PAGE_CACHE_SIZE);
|
| 150 |
|
|
|
| 151 |
|
|
flush_dcache_page(page);
|
| 152 |
|
|
SetPageUptodate(page);
|
| 153 |
|
|
kunmap(page);
|
| 154 |
|
|
unlock_page(page);
|
| 155 |
|
|
if ( fpage == xpage )
|
| 156 |
|
|
err = 0; /* The critical page */
|
| 157 |
|
|
else
|
| 158 |
|
|
page_cache_release(page);
|
| 159 |
|
|
}
|
| 160 |
|
|
}
|
| 161 |
|
|
} else {
|
| 162 |
|
|
/* This data block is compressed. */
|
| 163 |
|
|
z_stream stream;
|
| 164 |
|
|
int bail = 0, left_out = -1;
|
| 165 |
|
|
int zerr;
|
| 166 |
|
|
int needblocks = (csize + (cstart & bufmask) + bufmask) >> bufshift;
|
| 167 |
|
|
int haveblocks;
|
| 168 |
|
|
struct buffer_head *bhs[needblocks+1];
|
| 169 |
|
|
struct buffer_head **bhptr;
|
| 170 |
|
|
|
| 171 |
|
|
/* Because zlib is not thread-safe, do all the I/O at the top. */
|
| 172 |
|
|
|
| 173 |
|
|
blockptr = cstart >> bufshift;
|
| 174 |
|
|
memset(bhs, 0, (needblocks+1)*sizeof(struct buffer_head *));
|
| 175 |
|
|
haveblocks = isofs_get_blocks(inode, blockptr, bhs, needblocks);
|
| 176 |
|
|
ll_rw_block(READ, haveblocks, bhs);
|
| 177 |
|
|
|
| 178 |
|
|
bhptr = &bhs[0];
|
| 179 |
|
|
bh = *bhptr++;
|
| 180 |
|
|
|
| 181 |
|
|
/* First block is special since it may be fractional.
|
| 182 |
|
|
We also wait for it before grabbing the zlib
|
| 183 |
|
|
mutex; odds are that the subsequent blocks are
|
| 184 |
|
|
going to come in in short order so we don't hold
|
| 185 |
|
|
the zlib mutex longer than necessary. */
|
| 186 |
|
|
|
| 187 |
|
|
if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
|
| 188 |
|
|
printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
|
| 189 |
|
|
fpage, xpage, csize);
|
| 190 |
|
|
goto b_eio;
|
| 191 |
|
|
}
|
| 192 |
|
|
stream.next_in = bh->b_data + (cstart & bufmask);
|
| 193 |
|
|
stream.avail_in = min(bufsize-(cstart & bufmask), csize);
|
| 194 |
|
|
csize -= stream.avail_in;
|
| 195 |
|
|
|
| 196 |
|
|
stream.workspace = zisofs_zlib_workspace;
|
| 197 |
|
|
mutex_lock(&zisofs_zlib_lock);
|
| 198 |
|
|
|
| 199 |
|
|
zerr = zlib_inflateInit(&stream);
|
| 200 |
|
|
if ( zerr != Z_OK ) {
|
| 201 |
|
|
if ( err && zerr == Z_MEM_ERROR )
|
| 202 |
|
|
err = -ENOMEM;
|
| 203 |
|
|
printk(KERN_DEBUG "zisofs: zisofs_inflateInit returned %d\n",
|
| 204 |
|
|
zerr);
|
| 205 |
|
|
goto z_eio;
|
| 206 |
|
|
}
|
| 207 |
|
|
|
| 208 |
|
|
while ( !bail && fpage < maxpage ) {
|
| 209 |
|
|
page = pages[fpage];
|
| 210 |
|
|
if ( page )
|
| 211 |
|
|
stream.next_out = page_address(page);
|
| 212 |
|
|
else
|
| 213 |
|
|
stream.next_out = (void *)&zisofs_sink_page;
|
| 214 |
|
|
stream.avail_out = PAGE_CACHE_SIZE;
|
| 215 |
|
|
|
| 216 |
|
|
while ( stream.avail_out ) {
|
| 217 |
|
|
int ao, ai;
|
| 218 |
|
|
if ( stream.avail_in == 0 && left_out ) {
|
| 219 |
|
|
if ( !csize ) {
|
| 220 |
|
|
printk(KERN_WARNING "zisofs: ZF read beyond end of input\n");
|
| 221 |
|
|
bail = 1;
|
| 222 |
|
|
break;
|
| 223 |
|
|
} else {
|
| 224 |
|
|
bh = *bhptr++;
|
| 225 |
|
|
if ( !bh ||
|
| 226 |
|
|
(wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
|
| 227 |
|
|
/* Reached an EIO */
|
| 228 |
|
|
printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
|
| 229 |
|
|
fpage, xpage, csize);
|
| 230 |
|
|
|
| 231 |
|
|
bail = 1;
|
| 232 |
|
|
break;
|
| 233 |
|
|
}
|
| 234 |
|
|
stream.next_in = bh->b_data;
|
| 235 |
|
|
stream.avail_in = min(csize,bufsize);
|
| 236 |
|
|
csize -= stream.avail_in;
|
| 237 |
|
|
}
|
| 238 |
|
|
}
|
| 239 |
|
|
ao = stream.avail_out; ai = stream.avail_in;
|
| 240 |
|
|
zerr = zlib_inflate(&stream, Z_SYNC_FLUSH);
|
| 241 |
|
|
left_out = stream.avail_out;
|
| 242 |
|
|
if ( zerr == Z_BUF_ERROR && stream.avail_in == 0 )
|
| 243 |
|
|
continue;
|
| 244 |
|
|
if ( zerr != Z_OK ) {
|
| 245 |
|
|
/* EOF, error, or trying to read beyond end of input */
|
| 246 |
|
|
if ( err && zerr == Z_MEM_ERROR )
|
| 247 |
|
|
err = -ENOMEM;
|
| 248 |
|
|
if ( zerr != Z_STREAM_END )
|
| 249 |
|
|
printk(KERN_DEBUG "zisofs: zisofs_inflate returned %d, inode = %lu, index = %lu, fpage = %d, xpage = %d, avail_in = %d, avail_out = %d, ai = %d, ao = %d\n",
|
| 250 |
|
|
zerr, inode->i_ino, index,
|
| 251 |
|
|
fpage, xpage,
|
| 252 |
|
|
stream.avail_in, stream.avail_out,
|
| 253 |
|
|
ai, ao);
|
| 254 |
|
|
bail = 1;
|
| 255 |
|
|
break;
|
| 256 |
|
|
}
|
| 257 |
|
|
}
|
| 258 |
|
|
|
| 259 |
|
|
if ( stream.avail_out && zerr == Z_STREAM_END ) {
|
| 260 |
|
|
/* Fractional page written before EOF. This may
|
| 261 |
|
|
be the last page in the file. */
|
| 262 |
|
|
memset(stream.next_out, 0, stream.avail_out);
|
| 263 |
|
|
stream.avail_out = 0;
|
| 264 |
|
|
}
|
| 265 |
|
|
|
| 266 |
|
|
if ( !stream.avail_out ) {
|
| 267 |
|
|
/* This page completed */
|
| 268 |
|
|
if ( page ) {
|
| 269 |
|
|
flush_dcache_page(page);
|
| 270 |
|
|
SetPageUptodate(page);
|
| 271 |
|
|
kunmap(page);
|
| 272 |
|
|
unlock_page(page);
|
| 273 |
|
|
if ( fpage == xpage )
|
| 274 |
|
|
err = 0; /* The critical page */
|
| 275 |
|
|
else
|
| 276 |
|
|
page_cache_release(page);
|
| 277 |
|
|
}
|
| 278 |
|
|
fpage++;
|
| 279 |
|
|
}
|
| 280 |
|
|
}
|
| 281 |
|
|
zlib_inflateEnd(&stream);
|
| 282 |
|
|
|
| 283 |
|
|
z_eio:
|
| 284 |
|
|
mutex_unlock(&zisofs_zlib_lock);
|
| 285 |
|
|
|
| 286 |
|
|
b_eio:
|
| 287 |
|
|
for ( i = 0 ; i < haveblocks ; i++ ) {
|
| 288 |
|
|
if ( bhs[i] )
|
| 289 |
|
|
brelse(bhs[i]);
|
| 290 |
|
|
}
|
| 291 |
|
|
}
|
| 292 |
|
|
|
| 293 |
|
|
eio:
|
| 294 |
|
|
|
| 295 |
|
|
/* Release any residual pages, do not SetPageUptodate */
|
| 296 |
|
|
while ( fpage < maxpage ) {
|
| 297 |
|
|
page = pages[fpage];
|
| 298 |
|
|
if ( page ) {
|
| 299 |
|
|
flush_dcache_page(page);
|
| 300 |
|
|
if ( fpage == xpage )
|
| 301 |
|
|
SetPageError(page);
|
| 302 |
|
|
kunmap(page);
|
| 303 |
|
|
unlock_page(page);
|
| 304 |
|
|
if ( fpage != xpage )
|
| 305 |
|
|
page_cache_release(page);
|
| 306 |
|
|
}
|
| 307 |
|
|
fpage++;
|
| 308 |
|
|
}
|
| 309 |
|
|
|
| 310 |
|
|
/* At this point, err contains 0 or -EIO depending on the "critical" page */
|
| 311 |
|
|
return err;
|
| 312 |
|
|
}
|
| 313 |
|
|
|
| 314 |
|
|
const struct address_space_operations zisofs_aops = {
|
| 315 |
|
|
.readpage = zisofs_readpage,
|
| 316 |
|
|
/* No sync_page operation supported? */
|
| 317 |
|
|
/* No bmap operation supported */
|
| 318 |
|
|
};
|
| 319 |
|
|
|
| 320 |
|
|
int __init zisofs_init(void)
|
| 321 |
|
|
{
|
| 322 |
|
|
zisofs_zlib_workspace = vmalloc(zlib_inflate_workspacesize());
|
| 323 |
|
|
if ( !zisofs_zlib_workspace )
|
| 324 |
|
|
return -ENOMEM;
|
| 325 |
|
|
|
| 326 |
|
|
return 0;
|
| 327 |
|
|
}
|
| 328 |
|
|
|
| 329 |
|
|
void zisofs_cleanup(void)
|
| 330 |
|
|
{
|
| 331 |
|
|
vfree(zisofs_zlib_workspace);
|
| 332 |
|
|
}
|
