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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (C) 2008 Oracle. All rights reserved.
- *
- * Based on jffs2 zlib code:
- * Copyright © 2001-2007 Red Hat, Inc.
- * Created by David Woodhouse <dwmw2@infradead.org>
- */
- #include <linux/kernel.h>
- #include <linux/slab.h>
- #include <linux/zlib.h>
- #include <linux/zutil.h>
- #include <linux/mm.h>
- #include <linux/init.h>
- #include <linux/err.h>
- #include <linux/sched.h>
- #include <linux/pagemap.h>
- #include <linux/bio.h>
- #include <linux/refcount.h>
- #include "compression.h"
- /* workspace buffer size for s390 zlib hardware support */
- #define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
- struct workspace {
- z_stream strm;
- char *buf;
- unsigned int buf_size;
- struct list_head list;
- int level;
- };
- static struct workspace_manager wsm;
- struct list_head *zlib_get_workspace(unsigned int level)
- {
- struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
- struct workspace *workspace = list_entry(ws, struct workspace, list);
- workspace->level = level;
- return ws;
- }
- void zlib_free_workspace(struct list_head *ws)
- {
- struct workspace *workspace = list_entry(ws, struct workspace, list);
- kvfree(workspace->strm.workspace);
- kfree(workspace->buf);
- kfree(workspace);
- }
- struct list_head *zlib_alloc_workspace(unsigned int level)
- {
- struct workspace *workspace;
- int workspacesize;
- workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
- if (!workspace)
- return ERR_PTR(-ENOMEM);
- workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
- zlib_inflate_workspacesize());
- workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
- workspace->level = level;
- workspace->buf = NULL;
- /*
- * In case of s390 zlib hardware support, allocate lager workspace
- * buffer. If allocator fails, fall back to a single page buffer.
- */
- if (zlib_deflate_dfltcc_enabled()) {
- workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
- __GFP_NOMEMALLOC | __GFP_NORETRY |
- __GFP_NOWARN | GFP_NOIO);
- workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
- }
- if (!workspace->buf) {
- workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- workspace->buf_size = PAGE_SIZE;
- }
- if (!workspace->strm.workspace || !workspace->buf)
- goto fail;
- INIT_LIST_HEAD(&workspace->list);
- return &workspace->list;
- fail:
- zlib_free_workspace(&workspace->list);
- return ERR_PTR(-ENOMEM);
- }
- int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
- u64 start, struct page **pages, unsigned long *out_pages,
- unsigned long *total_in, unsigned long *total_out)
- {
- struct workspace *workspace = list_entry(ws, struct workspace, list);
- int ret;
- char *data_in;
- char *cpage_out;
- int nr_pages = 0;
- struct page *in_page = NULL;
- struct page *out_page = NULL;
- unsigned long bytes_left;
- unsigned int in_buf_pages;
- unsigned long len = *total_out;
- unsigned long nr_dest_pages = *out_pages;
- const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
- *out_pages = 0;
- *total_out = 0;
- *total_in = 0;
- if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
- pr_warn("BTRFS: deflateInit failed\n");
- ret = -EIO;
- goto out;
- }
- workspace->strm.total_in = 0;
- workspace->strm.total_out = 0;
- out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
- if (out_page == NULL) {
- ret = -ENOMEM;
- goto out;
- }
- cpage_out = kmap(out_page);
- pages[0] = out_page;
- nr_pages = 1;
- workspace->strm.next_in = workspace->buf;
- workspace->strm.avail_in = 0;
- workspace->strm.next_out = cpage_out;
- workspace->strm.avail_out = PAGE_SIZE;
- while (workspace->strm.total_in < len) {
- /*
- * Get next input pages and copy the contents to
- * the workspace buffer if required.
- */
- if (workspace->strm.avail_in == 0) {
- bytes_left = len - workspace->strm.total_in;
- in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
- workspace->buf_size / PAGE_SIZE);
- if (in_buf_pages > 1) {
- int i;
- for (i = 0; i < in_buf_pages; i++) {
- if (in_page) {
- kunmap(in_page);
- put_page(in_page);
- }
- in_page = find_get_page(mapping,
- start >> PAGE_SHIFT);
- data_in = kmap(in_page);
- memcpy(workspace->buf + i * PAGE_SIZE,
- data_in, PAGE_SIZE);
- start += PAGE_SIZE;
- }
- workspace->strm.next_in = workspace->buf;
- } else {
- if (in_page) {
- kunmap(in_page);
- put_page(in_page);
- }
- in_page = find_get_page(mapping,
- start >> PAGE_SHIFT);
- data_in = kmap(in_page);
- start += PAGE_SIZE;
- workspace->strm.next_in = data_in;
- }
- workspace->strm.avail_in = min(bytes_left,
- (unsigned long) workspace->buf_size);
- }
- ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
- if (ret != Z_OK) {
- pr_debug("BTRFS: deflate in loop returned %d\n",
- ret);
- zlib_deflateEnd(&workspace->strm);
- ret = -EIO;
- goto out;
- }
- /* we're making it bigger, give up */
- if (workspace->strm.total_in > 8192 &&
- workspace->strm.total_in <
- workspace->strm.total_out) {
- ret = -E2BIG;
- goto out;
- }
- /* we need another page for writing out. Test this
- * before the total_in so we will pull in a new page for
- * the stream end if required
- */
- if (workspace->strm.avail_out == 0) {
- kunmap(out_page);
- if (nr_pages == nr_dest_pages) {
- out_page = NULL;
- ret = -E2BIG;
- goto out;
- }
- out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
- if (out_page == NULL) {
- ret = -ENOMEM;
- goto out;
- }
- cpage_out = kmap(out_page);
- pages[nr_pages] = out_page;
- nr_pages++;
- workspace->strm.avail_out = PAGE_SIZE;
- workspace->strm.next_out = cpage_out;
- }
- /* we're all done */
- if (workspace->strm.total_in >= len)
- break;
- if (workspace->strm.total_out > max_out)
- break;
- }
- workspace->strm.avail_in = 0;
- /*
- * Call deflate with Z_FINISH flush parameter providing more output
- * space but no more input data, until it returns with Z_STREAM_END.
- */
- while (ret != Z_STREAM_END) {
- ret = zlib_deflate(&workspace->strm, Z_FINISH);
- if (ret == Z_STREAM_END)
- break;
- if (ret != Z_OK && ret != Z_BUF_ERROR) {
- zlib_deflateEnd(&workspace->strm);
- ret = -EIO;
- goto out;
- } else if (workspace->strm.avail_out == 0) {
- /* get another page for the stream end */
- kunmap(out_page);
- if (nr_pages == nr_dest_pages) {
- out_page = NULL;
- ret = -E2BIG;
- goto out;
- }
- out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
- if (out_page == NULL) {
- ret = -ENOMEM;
- goto out;
- }
- cpage_out = kmap(out_page);
- pages[nr_pages] = out_page;
- nr_pages++;
- workspace->strm.avail_out = PAGE_SIZE;
- workspace->strm.next_out = cpage_out;
- }
- }
- zlib_deflateEnd(&workspace->strm);
- if (workspace->strm.total_out >= workspace->strm.total_in) {
- ret = -E2BIG;
- goto out;
- }
- ret = 0;
- *total_out = workspace->strm.total_out;
- *total_in = workspace->strm.total_in;
- out:
- *out_pages = nr_pages;
- if (out_page)
- kunmap(out_page);
- if (in_page) {
- kunmap(in_page);
- put_page(in_page);
- }
- return ret;
- }
- int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
- {
- struct workspace *workspace = list_entry(ws, struct workspace, list);
- int ret = 0, ret2;
- int wbits = MAX_WBITS;
- char *data_in;
- size_t total_out = 0;
- unsigned long page_in_index = 0;
- size_t srclen = cb->compressed_len;
- unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
- unsigned long buf_start;
- struct page **pages_in = cb->compressed_pages;
- u64 disk_start = cb->start;
- struct bio *orig_bio = cb->orig_bio;
- data_in = kmap(pages_in[page_in_index]);
- workspace->strm.next_in = data_in;
- workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
- workspace->strm.total_in = 0;
- workspace->strm.total_out = 0;
- workspace->strm.next_out = workspace->buf;
- workspace->strm.avail_out = workspace->buf_size;
- /* If it's deflate, and it's got no preset dictionary, then
- we can tell zlib to skip the adler32 check. */
- if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
- ((data_in[0] & 0x0f) == Z_DEFLATED) &&
- !(((data_in[0]<<8) + data_in[1]) % 31)) {
- wbits = -((data_in[0] >> 4) + 8);
- workspace->strm.next_in += 2;
- workspace->strm.avail_in -= 2;
- }
- if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
- pr_warn("BTRFS: inflateInit failed\n");
- kunmap(pages_in[page_in_index]);
- return -EIO;
- }
- while (workspace->strm.total_in < srclen) {
- ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
- if (ret != Z_OK && ret != Z_STREAM_END)
- break;
- buf_start = total_out;
- total_out = workspace->strm.total_out;
- /* we didn't make progress in this inflate call, we're done */
- if (buf_start == total_out)
- break;
- ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
- total_out, disk_start,
- orig_bio);
- if (ret2 == 0) {
- ret = 0;
- goto done;
- }
- workspace->strm.next_out = workspace->buf;
- workspace->strm.avail_out = workspace->buf_size;
- if (workspace->strm.avail_in == 0) {
- unsigned long tmp;
- kunmap(pages_in[page_in_index]);
- page_in_index++;
- if (page_in_index >= total_pages_in) {
- data_in = NULL;
- break;
- }
- data_in = kmap(pages_in[page_in_index]);
- workspace->strm.next_in = data_in;
- tmp = srclen - workspace->strm.total_in;
- workspace->strm.avail_in = min(tmp,
- PAGE_SIZE);
- }
- }
- if (ret != Z_STREAM_END)
- ret = -EIO;
- else
- ret = 0;
- done:
- zlib_inflateEnd(&workspace->strm);
- if (data_in)
- kunmap(pages_in[page_in_index]);
- if (!ret)
- zero_fill_bio(orig_bio);
- return ret;
- }
- int zlib_decompress(struct list_head *ws, unsigned char *data_in,
- struct page *dest_page, unsigned long start_byte, size_t srclen,
- size_t destlen)
- {
- struct workspace *workspace = list_entry(ws, struct workspace, list);
- int ret = 0;
- int wbits = MAX_WBITS;
- unsigned long bytes_left;
- unsigned long total_out = 0;
- unsigned long pg_offset = 0;
- char *kaddr;
- destlen = min_t(unsigned long, destlen, PAGE_SIZE);
- bytes_left = destlen;
- workspace->strm.next_in = data_in;
- workspace->strm.avail_in = srclen;
- workspace->strm.total_in = 0;
- workspace->strm.next_out = workspace->buf;
- workspace->strm.avail_out = workspace->buf_size;
- workspace->strm.total_out = 0;
- /* If it's deflate, and it's got no preset dictionary, then
- we can tell zlib to skip the adler32 check. */
- if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
- ((data_in[0] & 0x0f) == Z_DEFLATED) &&
- !(((data_in[0]<<8) + data_in[1]) % 31)) {
- wbits = -((data_in[0] >> 4) + 8);
- workspace->strm.next_in += 2;
- workspace->strm.avail_in -= 2;
- }
- if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
- pr_warn("BTRFS: inflateInit failed\n");
- return -EIO;
- }
- while (bytes_left > 0) {
- unsigned long buf_start;
- unsigned long buf_offset;
- unsigned long bytes;
- ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
- if (ret != Z_OK && ret != Z_STREAM_END)
- break;
- buf_start = total_out;
- total_out = workspace->strm.total_out;
- if (total_out == buf_start) {
- ret = -EIO;
- break;
- }
- if (total_out <= start_byte)
- goto next;
- if (total_out > start_byte && buf_start < start_byte)
- buf_offset = start_byte - buf_start;
- else
- buf_offset = 0;
- bytes = min(PAGE_SIZE - pg_offset,
- PAGE_SIZE - (buf_offset % PAGE_SIZE));
- bytes = min(bytes, bytes_left);
- kaddr = kmap_atomic(dest_page);
- memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
- kunmap_atomic(kaddr);
- pg_offset += bytes;
- bytes_left -= bytes;
- next:
- workspace->strm.next_out = workspace->buf;
- workspace->strm.avail_out = workspace->buf_size;
- }
- if (ret != Z_STREAM_END && bytes_left != 0)
- ret = -EIO;
- else
- ret = 0;
- zlib_inflateEnd(&workspace->strm);
- /*
- * this should only happen if zlib returned fewer bytes than we
- * expected. btrfs_get_block is responsible for zeroing from the
- * end of the inline extent (destlen) to the end of the page
- */
- if (pg_offset < destlen) {
- kaddr = kmap_atomic(dest_page);
- memset(kaddr + pg_offset, 0, destlen - pg_offset);
- kunmap_atomic(kaddr);
- }
- return ret;
- }
- const struct btrfs_compress_op btrfs_zlib_compress = {
- .workspace_manager = &wsm,
- .max_level = 9,
- .default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
- };
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