[net-next-2.6.git] / fs / isofs / compress.c

/* -*- linux-c -*- ------------------------------------------------------- *
 *   
 *   Copyright 2001 H. Peter Anvin - All Rights Reserved
 *
 *   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, Inc., 675 Mass Ave, Cambridge MA 02139,
 *   USA; either version 2 of the License, or (at your option) any later
 *   version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

/*
 * linux/fs/isofs/compress.c
 *
 * Transparent decompression of files on an iso9660 filesystem
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>

#include <linux/vmalloc.h>
#include <linux/zlib.h>

#include "isofs.h"
#include "zisofs.h"

/* This should probably be global. */
static char zisofs_sink_page[PAGE_CACHE_SIZE];

/*
 * This contains the zlib memory allocation and the mutex for the
 * allocation; this avoids failures at block-decompression time.
 */
static void *zisofs_zlib_workspace;
static struct semaphore zisofs_zlib_semaphore;

/*
 * When decompressing, we typically obtain more than one page
 * per reference.  We inject the additional pages into the page
 * cache as a form of readahead.
 */
static int zisofs_readpage(struct file *file, struct page *page)
{
	struct inode *inode = file->f_dentry->d_inode;
	struct address_space *mapping = inode->i_mapping;
	unsigned int maxpage, xpage, fpage, blockindex;
	unsigned long offset;
	unsigned long blockptr, blockendptr, cstart, cend, csize;
	struct buffer_head *bh, *ptrbh[2];
	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	unsigned int bufshift = ISOFS_BUFFER_BITS(inode);
	unsigned long bufmask  = bufsize - 1;
	int err = -EIO;
	int i;
	unsigned int header_size = ISOFS_I(inode)->i_format_parm[0];
	unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
	/* unsigned long zisofs_block_size = 1UL << zisofs_block_shift; */
	unsigned int zisofs_block_page_shift = zisofs_block_shift-PAGE_CACHE_SHIFT;
	unsigned long zisofs_block_pages = 1UL << zisofs_block_page_shift;
	unsigned long zisofs_block_page_mask = zisofs_block_pages-1;
	struct page *pages[zisofs_block_pages];
	unsigned long index = page->index;
	int indexblocks;

	/* We have already been given one page, this is the one
	   we must do. */
	xpage = index & zisofs_block_page_mask;
	pages[xpage] = page;
 
	/* The remaining pages need to be allocated and inserted */
	offset = index & ~zisofs_block_page_mask;
	blockindex = offset >> zisofs_block_page_shift;
	maxpage = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
	maxpage = min(zisofs_block_pages, maxpage-offset);

	for ( i = 0 ; i < maxpage ; i++, offset++ ) {
		if ( i != xpage ) {
			pages[i] = grab_cache_page_nowait(mapping, offset);
		}
		page = pages[i];
		if ( page ) {
			ClearPageError(page);
			kmap(page);
		}
	}

	/* This is the last page filled, plus one; used in case of abort. */
	fpage = 0;

	/* Find the pointer to this specific chunk */
	/* Note: we're not using isonum_731() here because the data is known aligned */
	/* Note: header_size is in 32-bit words (4 bytes) */
	blockptr = (header_size + blockindex) << 2;
	blockendptr = blockptr + 4;

	indexblocks = ((blockptr^blockendptr) >> bufshift) ? 2 : 1;
	ptrbh[0] = ptrbh[1] = NULL;

	if ( isofs_get_blocks(inode, blockptr >> bufshift, ptrbh, indexblocks) != indexblocks ) {
		if ( ptrbh[0] ) brelse(ptrbh[0]);
		printk(KERN_DEBUG "zisofs: Null buffer on reading block table, inode = %lu, block = %lu\n",
		       inode->i_ino, blockptr >> bufshift);
		goto eio;
	}
	ll_rw_block(READ, indexblocks, ptrbh);

	bh = ptrbh[0];
	if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
		printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
		       inode->i_ino, blockptr >> bufshift);
		if ( ptrbh[1] )
			brelse(ptrbh[1]);
		goto eio;
	}
	cstart = le32_to_cpu(*(__le32 *)(bh->b_data + (blockptr & bufmask)));

	if ( indexblocks == 2 ) {
		/* We just crossed a block boundary.  Switch to the next block */
		brelse(bh);
		bh = ptrbh[1];
		if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
			printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
			       inode->i_ino, blockendptr >> bufshift);
			goto eio;
		}
	}
	cend = le32_to_cpu(*(__le32 *)(bh->b_data + (blockendptr & bufmask)));
	brelse(bh);

	if (cstart > cend)
		goto eio;
		
	csize = cend-cstart;

	if (csize > deflateBound(1UL << zisofs_block_shift))
		goto eio;

	/* Now page[] contains an array of pages, any of which can be NULL,
	   and the locks on which we hold.  We should now read the data and
	   release the pages.  If the pages are NULL the decompressed data
	   for that particular page should be discarded. */
	
	if ( csize == 0 ) {
		/* This data block is empty. */

		for ( fpage = 0 ; fpage < maxpage ; fpage++ ) {
			if ( (page = pages[fpage]) != NULL ) {
				memset(page_address(page), 0, PAGE_CACHE_SIZE);
				
				flush_dcache_page(page);
				SetPageUptodate(page);
				kunmap(page);
				unlock_page(page);
				if ( fpage == xpage )
					err = 0; /* The critical page */
				else
					page_cache_release(page);
			}
		}
	} else {
		/* This data block is compressed. */
		z_stream stream;
		int bail = 0, left_out = -1;
		int zerr;
		int needblocks = (csize + (cstart & bufmask) + bufmask) >> bufshift;
		int haveblocks;
		struct buffer_head *bhs[needblocks+1];
		struct buffer_head **bhptr;

		/* Because zlib is not thread-safe, do all the I/O at the top. */

		blockptr = cstart >> bufshift;
		memset(bhs, 0, (needblocks+1)*sizeof(struct buffer_head *));
		haveblocks = isofs_get_blocks(inode, blockptr, bhs, needblocks);
		ll_rw_block(READ, haveblocks, bhs);

		bhptr = &bhs[0];
		bh = *bhptr++;

		/* First block is special since it may be fractional.
		   We also wait for it before grabbing the zlib
		   semaphore; odds are that the subsequent blocks are
		   going to come in in short order so we don't hold
		   the zlib semaphore longer than necessary. */

		if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
			printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
			       fpage, xpage, csize);
			goto b_eio;
		}
		stream.next_in  = bh->b_data + (cstart & bufmask);
		stream.avail_in = min(bufsize-(cstart & bufmask), csize);
		csize -= stream.avail_in;

		stream.workspace = zisofs_zlib_workspace;
		down(&zisofs_zlib_semaphore);
		
		zerr = zlib_inflateInit(&stream);
		if ( zerr != Z_OK ) {
			if ( err && zerr == Z_MEM_ERROR )
				err = -ENOMEM;
			printk(KERN_DEBUG "zisofs: zisofs_inflateInit returned %d\n",
			       zerr);
			goto z_eio;
		}

		while ( !bail && fpage < maxpage ) {
			page = pages[fpage];
			if ( page )
				stream.next_out = page_address(page);
			else
				stream.next_out = (void *)&zisofs_sink_page;
			stream.avail_out = PAGE_CACHE_SIZE;

			while ( stream.avail_out ) {
				int ao, ai;
				if ( stream.avail_in == 0 && left_out ) {
					if ( !csize ) {
						printk(KERN_WARNING "zisofs: ZF read beyond end of input\n");
						bail = 1;
						break;
					} else {
						bh = *bhptr++;
						if ( !bh ||
						     (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
							/* Reached an EIO */
 							printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
							       fpage, xpage, csize);
							       
							bail = 1;
							break;
						}
						stream.next_in = bh->b_data;
						stream.avail_in = min(csize,bufsize);
						csize -= stream.avail_in;
					}
				}
				ao = stream.avail_out;  ai = stream.avail_in;
				zerr = zlib_inflate(&stream, Z_SYNC_FLUSH);
				left_out = stream.avail_out;
				if ( zerr == Z_BUF_ERROR && stream.avail_in == 0 )
					continue;
				if ( zerr != Z_OK ) {
					/* EOF, error, or trying to read beyond end of input */
					if ( err && zerr == Z_MEM_ERROR )
						err = -ENOMEM;
					if ( zerr != Z_STREAM_END )
						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",
						       zerr, inode->i_ino, index,
						       fpage, xpage,
						       stream.avail_in, stream.avail_out,
						       ai, ao);
					bail = 1;
					break;
				}
			}

			if ( stream.avail_out && zerr == Z_STREAM_END ) {
				/* Fractional page written before EOF.  This may
				   be the last page in the file. */
				memset(stream.next_out, 0, stream.avail_out);
				stream.avail_out = 0;
			}

			if ( !stream.avail_out ) {
				/* This page completed */
				if ( page ) {
					flush_dcache_page(page);
					SetPageUptodate(page);
					kunmap(page);
					unlock_page(page);
					if ( fpage == xpage )
						err = 0; /* The critical page */
					else
						page_cache_release(page);
				}
				fpage++;
			}
		}
		zlib_inflateEnd(&stream);

	z_eio:
		up(&zisofs_zlib_semaphore);

	b_eio:
		for ( i = 0 ; i < haveblocks ; i++ ) {
			if ( bhs[i] )
				brelse(bhs[i]);
		}
	}

eio:

	/* Release any residual pages, do not SetPageUptodate */
	while ( fpage < maxpage ) {
		page = pages[fpage];
		if ( page ) {
			flush_dcache_page(page);
			if ( fpage == xpage )
				SetPageError(page);
			kunmap(page);
			unlock_page(page);
			if ( fpage != xpage )
				page_cache_release(page);
		}
		fpage++;
	}			

	/* At this point, err contains 0 or -EIO depending on the "critical" page */
	return err;
}

const struct address_space_operations zisofs_aops = {
	.readpage = zisofs_readpage,
	/* No sync_page operation supported? */
	/* No bmap operation supported */
};

static int initialized;

int __init zisofs_init(void)
{
	if ( initialized ) {
		printk("zisofs_init: called more than once\n");
		return 0;
	}

	zisofs_zlib_workspace = vmalloc(zlib_inflate_workspacesize());
	if ( !zisofs_zlib_workspace )
		return -ENOMEM;
	init_MUTEX(&zisofs_zlib_semaphore);

	initialized = 1;
	return 0;
}

void zisofs_cleanup(void)
{
	if ( !initialized ) {
		printk("zisofs_cleanup: called without initialization\n");
		return;
	}

	vfree(zisofs_zlib_workspace);
	initialized = 0;
}
Commit	Line	Data
1da177e4 LT	1	/* -- 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/config.h>
	20	#include <linux/module.h>
1da177e4	21	#include <linux/init.h>
94f2f715	22
1da177e4 LT	23	#include <linux/vmalloc.h>
1da177e4 LT	24	#include <linux/zlib.h>
1da177e4	25
94f2f715	26	#include "isofs.h"
1da177e4 LT	27	#include "zisofs.h"
	28
	29	/* This should probably be global. */
	30	static char zisofs_sink_page[PAGE_CACHE_SIZE];
	31
	32	/*
	33	* This contains the zlib memory allocation and the mutex for the
	34	* allocation; this avoids failures at block-decompression time.
	35	*/
	36	static void *zisofs_zlib_workspace;
	37	static struct semaphore zisofs_zlib_semaphore;
	38
	39	/*
	40	* When decompressing, we typically obtain more than one page
	41	* per reference. We inject the additional pages into the page
	42	* cache as a form of readahead.
	43	*/
	44	static int zisofs_readpage(struct file file, struct page page)
	45	{
	46	struct inode *inode = file->f_dentry->d_inode;
	47	struct address_space *mapping = inode->i_mapping;
	48	unsigned int maxpage, xpage, fpage, blockindex;
	49	unsigned long offset;
	50	unsigned long blockptr, blockendptr, cstart, cend, csize;
	51	struct buffer_head bh, ptrbh[2];
	52	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	53	unsigned int bufshift = ISOFS_BUFFER_BITS(inode);
	54	unsigned long bufmask = bufsize - 1;
	55	int err = -EIO;
	56	int i;
	57	unsigned int header_size = ISOFS_I(inode)->i_format_parm[0];
	58	unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
	59	/* unsigned long zisofs_block_size = 1UL << zisofs_block_shift; */
	60	unsigned int zisofs_block_page_shift = zisofs_block_shift-PAGE_CACHE_SHIFT;
	61	unsigned long zisofs_block_pages = 1UL << zisofs_block_page_shift;
	62	unsigned long zisofs_block_page_mask = zisofs_block_pages-1;
	63	struct page *pages[zisofs_block_pages];
	64	unsigned long index = page->index;
	65	int indexblocks;
	66
	67	/* We have already been given one page, this is the one
	68	we must do. */
	69	xpage = index & zisofs_block_page_mask;
	70	pages[xpage] = page;
	71
	72	/* The remaining pages need to be allocated and inserted */
	73	offset = index & ~zisofs_block_page_mask;
	74	blockindex = offset >> zisofs_block_page_shift;
	75	maxpage = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
	76	maxpage = min(zisofs_block_pages, maxpage-offset);
	77
	78	for ( i = 0 ; i < maxpage ; i++, offset++ ) {
	79	if ( i != xpage ) {
	80	pages[i] = grab_cache_page_nowait(mapping, offset);
	81	}
	82	page = pages[i];
	83	if ( page ) {
	84	ClearPageError(page);
	85	kmap(page);
	86	}
	87	}
	88
	89	/* This is the last page filled, plus one; used in case of abort. */
	90	fpage = 0;
91
92	/* Find the pointer to this specific chunk */
93	/* Note: we're not using isonum_731() here because the data is known aligned */
94	/* Note: header_size is in 32-bit words (4 bytes) */
95	blockptr = (header_size + blockindex) << 2;
96	blockendptr = blockptr + 4;
97
98	indexblocks = ((blockptr^blockendptr) >> bufshift) ? 2 : 1;
99	ptrbh[0] = ptrbh[1] = NULL;
100
101	if ( isofs_get_blocks(inode, blockptr >> bufshift, ptrbh, indexblocks) != indexblocks ) {
102	if ( ptrbh[0] ) brelse(ptrbh[0]);
103	printk(KERN_DEBUG "zisofs: Null buffer on reading block table, inode = %lu, block = %lu\n",
104	inode->i_ino, blockptr >> bufshift);
105	goto eio;
106	}
107	ll_rw_block(READ, indexblocks, ptrbh);
108
109	bh = ptrbh[0];
110	if ( !bh \|\| (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
111	printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
112	inode->i_ino, blockptr >> bufshift);
113	if ( ptrbh[1] )
114	brelse(ptrbh[1]);
115	goto eio;
116	}
117	cstart = le32_to_cpu((__le32 )(bh->b_data + (blockptr & bufmask)));
118
119	if ( indexblocks == 2 ) {
120	/* We just crossed a block boundary. Switch to the next block */
121	brelse(bh);
122	bh = ptrbh[1];
123	if ( !bh \|\| (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
124	printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
125	inode->i_ino, blockendptr >> bufshift);
126	goto eio;
127	}
128	}
129	cend = le32_to_cpu((__le32 )(bh->b_data + (blockendptr & bufmask)));
130	brelse(bh);
131
fab5a60a LT	132	if (cstart > cend)
	133	goto eio;
	134
1da177e4 LT	135	csize = cend-cstart;
1da177e4 LT	136
fab5a60a LT	137	if (csize > deflateBound(1UL << zisofs_block_shift))
	138	goto eio;
	139
1da177e4 LT	140	/* Now page[] contains an array of pages, any of which can be NULL,
	141	and the locks on which we hold. We should now read the data and
	142	release the pages. If the pages are NULL the decompressed data
	143	for that particular page should be discarded. */
	144
	145	if ( csize == 0 ) {
	146	/* This data block is empty. */
	147
	148	for ( fpage = 0 ; fpage < maxpage ; fpage++ ) {
	149	if ( (page = pages[fpage]) != NULL ) {
	150	memset(page_address(page), 0, PAGE_CACHE_SIZE);
	151
	152	flush_dcache_page(page);
	153	SetPageUptodate(page);
	154	kunmap(page);
	155	unlock_page(page);
	156	if ( fpage == xpage )
	157	err = 0; /* The critical page */
	158	else
	159	page_cache_release(page);
	160	}
	161	}
	162	} else {
	163	/* This data block is compressed. */
	164	z_stream stream;
	165	int bail = 0, left_out = -1;
	166	int zerr;
	167	int needblocks = (csize + (cstart & bufmask) + bufmask) >> bufshift;
	168	int haveblocks;
	169	struct buffer_head *bhs[needblocks+1];
	170	struct buffer_head **bhptr;
	171
	172	/* Because zlib is not thread-safe, do all the I/O at the top. */
	173
	174	blockptr = cstart >> bufshift;
	175	memset(bhs, 0, (needblocks+1)sizeof(struct buffer_head ));
	176	haveblocks = isofs_get_blocks(inode, blockptr, bhs, needblocks);
	177	ll_rw_block(READ, haveblocks, bhs);
	178
	179	bhptr = &bhs[0];
	180	bh = *bhptr++;
	181
	182	/* First block is special since it may be fractional.
	183	We also wait for it before grabbing the zlib
	184	semaphore; odds are that the subsequent blocks are
	185	going to come in in short order so we don't hold
	186	the zlib semaphore longer than necessary. */
	187
	188	if ( !bh \|\| (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
	189	printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
	190	fpage, xpage, csize);
	191	goto b_eio;
	192	}
	193	stream.next_in = bh->b_data + (cstart & bufmask);
	194	stream.avail_in = min(bufsize-(cstart & bufmask), csize);
	195	csize -= stream.avail_in;
	196
	197	stream.workspace = zisofs_zlib_workspace;
	198	down(&zisofs_zlib_semaphore);
	199
	200	zerr = zlib_inflateInit(&stream);
	201	if ( zerr != Z_OK ) {
	202	if ( err && zerr == Z_MEM_ERROR )
	203	err = -ENOMEM;
204	printk(KERN_DEBUG "zisofs: zisofs_inflateInit returned %d\n",
205	zerr);
206	goto z_eio;
207	}
208
209	while ( !bail && fpage < maxpage ) {
210	page = pages[fpage];
211	if ( page )
212	stream.next_out = page_address(page);
213	else
214	stream.next_out = (void *)&zisofs_sink_page;
215	stream.avail_out = PAGE_CACHE_SIZE;
216
217	while ( stream.avail_out ) {
218	int ao, ai;
219	if ( stream.avail_in == 0 && left_out ) {
220	if ( !csize ) {
221	printk(KERN_WARNING "zisofs: ZF read beyond end of input\n");
222	bail = 1;
223	break;
224	} else {
225	bh = *bhptr++;
226	if ( !bh \|\|
227	(wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
228	/* Reached an EIO */
229	printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
230	fpage, xpage, csize);
231
232	bail = 1;
233	break;
234	}
235	stream.next_in = bh->b_data;
236	stream.avail_in = min(csize,bufsize);
237	csize -= stream.avail_in;
238	}
239	}
240	ao = stream.avail_out; ai = stream.avail_in;
241	zerr = zlib_inflate(&stream, Z_SYNC_FLUSH);
242	left_out = stream.avail_out;
243	if ( zerr == Z_BUF_ERROR && stream.avail_in == 0 )
244	continue;
245	if ( zerr != Z_OK ) {
246	/* EOF, error, or trying to read beyond end of input */
247	if ( err && zerr == Z_MEM_ERROR )
248	err = -ENOMEM;
249	if ( zerr != Z_STREAM_END )
250	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",
251	zerr, inode->i_ino, index,
252	fpage, xpage,
253	stream.avail_in, stream.avail_out,
254	ai, ao);
255	bail = 1;
256	break;
257	}
258	}
259
260	if ( stream.avail_out && zerr == Z_STREAM_END ) {
261	/* Fractional page written before EOF. This may
262	be the last page in the file. */
263	memset(stream.next_out, 0, stream.avail_out);
264	stream.avail_out = 0;
265	}
266
267	if ( !stream.avail_out ) {
268	/* This page completed */
269	if ( page ) {
270	flush_dcache_page(page);
271	SetPageUptodate(page);
272	kunmap(page);
273	unlock_page(page);
274	if ( fpage == xpage )
275	err = 0; /* The critical page */
276	else
277	page_cache_release(page);
278	}
279	fpage++;
280	}
281	}
282	zlib_inflateEnd(&stream);
283
284	z_eio:
285	up(&zisofs_zlib_semaphore);
286
287	b_eio:
288	for ( i = 0 ; i < haveblocks ; i++ ) {
289	if ( bhs[i] )
290	brelse(bhs[i]);
291	}
292	}
293
294	eio:
295
296	/* Release any residual pages, do not SetPageUptodate */
297	while ( fpage < maxpage ) {
298	page = pages[fpage];
299	if ( page ) {
300	flush_dcache_page(page);
301	if ( fpage == xpage )
302	SetPageError(page);
303	kunmap(page);
304	unlock_page(page);
305	if ( fpage != xpage )
306	page_cache_release(page);
307	}
308	fpage++;
309	}
310
311	/* At this point, err contains 0 or -EIO depending on the "critical" page */
312	return err;
313	}
314
f5e54d6e	315	const struct address_space_operations zisofs_aops = {
1da177e4 LT	316	.readpage = zisofs_readpage,
	317	/* No sync_page operation supported? */
	318	/* No bmap operation supported */
	319	};
	320
	321	static int initialized;
	322
	323	int __init zisofs_init(void)
	324	{
	325	if ( initialized ) {
	326	printk("zisofs_init: called more than once\n");
	327	return 0;
	328	}
	329
	330	zisofs_zlib_workspace = vmalloc(zlib_inflate_workspacesize());
	331	if ( !zisofs_zlib_workspace )
	332	return -ENOMEM;
	333	init_MUTEX(&zisofs_zlib_semaphore);
	334
	335	initialized = 1;
	336	return 0;
	337	}
	338
	339	void zisofs_cleanup(void)
	340	{
	341	if ( !initialized ) {
	342	printk("zisofs_cleanup: called without initialization\n");
	343	return;
	344	}
	345
	346	vfree(zisofs_zlib_workspace);
	347	initialized = 0;
	348	}