1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2008 Oracle. All rights reserved.
5 * Based on jffs2 zlib code:
6 * Copyright © 2001-2007 Red Hat, Inc.
7 * Created by David Woodhouse <dwmw2@infradead.org>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/zlib.h>
13 #include <linux/zutil.h>
15 #include <linux/init.h>
16 #include <linux/err.h>
17 #include <linux/sched.h>
18 #include <linux/pagemap.h>
19 #include <linux/bio.h>
20 #include <linux/refcount.h>
21 #include "compression.h"
23 /* workspace buffer size for s390 zlib hardware support */
24 #define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
29 unsigned int buf_size;
30 struct list_head list;
34 static struct workspace_manager wsm;
36 struct list_head *zlib_get_workspace(unsigned int level)
38 struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
39 struct workspace *workspace = list_entry(ws, struct workspace, list);
41 workspace->level = level;
46 void zlib_free_workspace(struct list_head *ws)
48 struct workspace *workspace = list_entry(ws, struct workspace, list);
50 kvfree(workspace->strm.workspace);
51 kfree(workspace->buf);
55 struct list_head *zlib_alloc_workspace(unsigned int level)
57 struct workspace *workspace;
60 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
62 return ERR_PTR(-ENOMEM);
64 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
65 zlib_inflate_workspacesize());
66 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
67 workspace->level = level;
68 workspace->buf = NULL;
70 * In case of s390 zlib hardware support, allocate lager workspace
71 * buffer. If allocator fails, fall back to a single page buffer.
73 if (zlib_deflate_dfltcc_enabled()) {
74 workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
75 __GFP_NOMEMALLOC | __GFP_NORETRY |
76 __GFP_NOWARN | GFP_NOIO);
77 workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
79 if (!workspace->buf) {
80 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
81 workspace->buf_size = PAGE_SIZE;
83 if (!workspace->strm.workspace || !workspace->buf)
86 INIT_LIST_HEAD(&workspace->list);
88 return &workspace->list;
90 zlib_free_workspace(&workspace->list);
91 return ERR_PTR(-ENOMEM);
94 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
95 u64 start, struct page **pages, unsigned long *out_pages,
96 unsigned long *total_in, unsigned long *total_out)
98 struct workspace *workspace = list_entry(ws, struct workspace, list);
103 struct page *in_page = NULL;
104 struct page *out_page = NULL;
105 unsigned long bytes_left;
106 unsigned int in_buf_pages;
107 unsigned long len = *total_out;
108 unsigned long nr_dest_pages = *out_pages;
109 const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
115 if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
116 pr_warn("BTRFS: deflateInit failed\n");
121 workspace->strm.total_in = 0;
122 workspace->strm.total_out = 0;
124 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
125 if (out_page == NULL) {
129 cpage_out = kmap(out_page);
133 workspace->strm.next_in = workspace->buf;
134 workspace->strm.avail_in = 0;
135 workspace->strm.next_out = cpage_out;
136 workspace->strm.avail_out = PAGE_SIZE;
138 while (workspace->strm.total_in < len) {
140 * Get next input pages and copy the contents to
141 * the workspace buffer if required.
143 if (workspace->strm.avail_in == 0) {
144 bytes_left = len - workspace->strm.total_in;
145 in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
146 workspace->buf_size / PAGE_SIZE);
147 if (in_buf_pages > 1) {
150 for (i = 0; i < in_buf_pages; i++) {
155 in_page = find_get_page(mapping,
156 start >> PAGE_SHIFT);
157 data_in = kmap(in_page);
158 memcpy(workspace->buf + i * PAGE_SIZE,
162 workspace->strm.next_in = workspace->buf;
168 in_page = find_get_page(mapping,
169 start >> PAGE_SHIFT);
170 data_in = kmap(in_page);
172 workspace->strm.next_in = data_in;
174 workspace->strm.avail_in = min(bytes_left,
175 (unsigned long) workspace->buf_size);
178 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
180 pr_debug("BTRFS: deflate in loop returned %d\n",
182 zlib_deflateEnd(&workspace->strm);
187 /* we're making it bigger, give up */
188 if (workspace->strm.total_in > 8192 &&
189 workspace->strm.total_in <
190 workspace->strm.total_out) {
194 /* we need another page for writing out. Test this
195 * before the total_in so we will pull in a new page for
196 * the stream end if required
198 if (workspace->strm.avail_out == 0) {
200 if (nr_pages == nr_dest_pages) {
205 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
206 if (out_page == NULL) {
210 cpage_out = kmap(out_page);
211 pages[nr_pages] = out_page;
213 workspace->strm.avail_out = PAGE_SIZE;
214 workspace->strm.next_out = cpage_out;
217 if (workspace->strm.total_in >= len)
219 if (workspace->strm.total_out > max_out)
222 workspace->strm.avail_in = 0;
224 * Call deflate with Z_FINISH flush parameter providing more output
225 * space but no more input data, until it returns with Z_STREAM_END.
227 while (ret != Z_STREAM_END) {
228 ret = zlib_deflate(&workspace->strm, Z_FINISH);
229 if (ret == Z_STREAM_END)
231 if (ret != Z_OK && ret != Z_BUF_ERROR) {
232 zlib_deflateEnd(&workspace->strm);
235 } else if (workspace->strm.avail_out == 0) {
236 /* get another page for the stream end */
238 if (nr_pages == nr_dest_pages) {
243 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
244 if (out_page == NULL) {
248 cpage_out = kmap(out_page);
249 pages[nr_pages] = out_page;
251 workspace->strm.avail_out = PAGE_SIZE;
252 workspace->strm.next_out = cpage_out;
255 zlib_deflateEnd(&workspace->strm);
257 if (workspace->strm.total_out >= workspace->strm.total_in) {
263 *total_out = workspace->strm.total_out;
264 *total_in = workspace->strm.total_in;
266 *out_pages = nr_pages;
277 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
279 struct workspace *workspace = list_entry(ws, struct workspace, list);
281 int wbits = MAX_WBITS;
283 size_t total_out = 0;
284 unsigned long page_in_index = 0;
285 size_t srclen = cb->compressed_len;
286 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
287 unsigned long buf_start;
288 struct page **pages_in = cb->compressed_pages;
289 u64 disk_start = cb->start;
290 struct bio *orig_bio = cb->orig_bio;
292 data_in = kmap(pages_in[page_in_index]);
293 workspace->strm.next_in = data_in;
294 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
295 workspace->strm.total_in = 0;
297 workspace->strm.total_out = 0;
298 workspace->strm.next_out = workspace->buf;
299 workspace->strm.avail_out = workspace->buf_size;
301 /* If it's deflate, and it's got no preset dictionary, then
302 we can tell zlib to skip the adler32 check. */
303 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
304 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
305 !(((data_in[0]<<8) + data_in[1]) % 31)) {
307 wbits = -((data_in[0] >> 4) + 8);
308 workspace->strm.next_in += 2;
309 workspace->strm.avail_in -= 2;
312 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
313 pr_warn("BTRFS: inflateInit failed\n");
314 kunmap(pages_in[page_in_index]);
317 while (workspace->strm.total_in < srclen) {
318 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
319 if (ret != Z_OK && ret != Z_STREAM_END)
322 buf_start = total_out;
323 total_out = workspace->strm.total_out;
325 /* we didn't make progress in this inflate call, we're done */
326 if (buf_start == total_out)
329 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
330 total_out, disk_start,
337 workspace->strm.next_out = workspace->buf;
338 workspace->strm.avail_out = workspace->buf_size;
340 if (workspace->strm.avail_in == 0) {
342 kunmap(pages_in[page_in_index]);
344 if (page_in_index >= total_pages_in) {
348 data_in = kmap(pages_in[page_in_index]);
349 workspace->strm.next_in = data_in;
350 tmp = srclen - workspace->strm.total_in;
351 workspace->strm.avail_in = min(tmp,
355 if (ret != Z_STREAM_END)
360 zlib_inflateEnd(&workspace->strm);
362 kunmap(pages_in[page_in_index]);
364 zero_fill_bio(orig_bio);
368 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
369 struct page *dest_page, unsigned long start_byte, size_t srclen,
372 struct workspace *workspace = list_entry(ws, struct workspace, list);
374 int wbits = MAX_WBITS;
375 unsigned long bytes_left;
376 unsigned long total_out = 0;
377 unsigned long pg_offset = 0;
380 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
381 bytes_left = destlen;
383 workspace->strm.next_in = data_in;
384 workspace->strm.avail_in = srclen;
385 workspace->strm.total_in = 0;
387 workspace->strm.next_out = workspace->buf;
388 workspace->strm.avail_out = workspace->buf_size;
389 workspace->strm.total_out = 0;
390 /* If it's deflate, and it's got no preset dictionary, then
391 we can tell zlib to skip the adler32 check. */
392 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
393 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
394 !(((data_in[0]<<8) + data_in[1]) % 31)) {
396 wbits = -((data_in[0] >> 4) + 8);
397 workspace->strm.next_in += 2;
398 workspace->strm.avail_in -= 2;
401 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
402 pr_warn("BTRFS: inflateInit failed\n");
406 while (bytes_left > 0) {
407 unsigned long buf_start;
408 unsigned long buf_offset;
411 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
412 if (ret != Z_OK && ret != Z_STREAM_END)
415 buf_start = total_out;
416 total_out = workspace->strm.total_out;
418 if (total_out == buf_start) {
423 if (total_out <= start_byte)
426 if (total_out > start_byte && buf_start < start_byte)
427 buf_offset = start_byte - buf_start;
431 bytes = min(PAGE_SIZE - pg_offset,
432 PAGE_SIZE - (buf_offset % PAGE_SIZE));
433 bytes = min(bytes, bytes_left);
435 kaddr = kmap_atomic(dest_page);
436 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
437 kunmap_atomic(kaddr);
442 workspace->strm.next_out = workspace->buf;
443 workspace->strm.avail_out = workspace->buf_size;
446 if (ret != Z_STREAM_END && bytes_left != 0)
451 zlib_inflateEnd(&workspace->strm);
454 * this should only happen if zlib returned fewer bytes than we
455 * expected. btrfs_get_block is responsible for zeroing from the
456 * end of the inline extent (destlen) to the end of the page
458 if (pg_offset < destlen) {
459 kaddr = kmap_atomic(dest_page);
460 memset(kaddr + pg_offset, 0, destlen - pg_offset);
461 kunmap_atomic(kaddr);
466 const struct btrfs_compress_op btrfs_zlib_compress = {
467 .workspace_manager = &wsm,
469 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL,