diff options
Diffstat (limited to 'fs/btrfs/zlib.c')
| -rw-r--r-- | fs/btrfs/zlib.c | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c new file mode 100644 index 000000000..94d06a76e --- /dev/null +++ b/fs/btrfs/zlib.c @@ -0,0 +1,456 @@ +// 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 = kvzalloc(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 = NULL; + 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); + if (out_page == NULL) { + ret = -ENOMEM; + goto out; + } + cpage_out = page_address(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 (data_in) { + kunmap_local(data_in); + put_page(in_page); + } + in_page = find_get_page(mapping, + start >> PAGE_SHIFT); + data_in = kmap_local_page(in_page); + memcpy(workspace->buf + i * PAGE_SIZE, + data_in, PAGE_SIZE); + start += PAGE_SIZE; + } + workspace->strm.next_in = workspace->buf; + } else { + if (data_in) { + kunmap_local(data_in); + put_page(in_page); + } + in_page = find_get_page(mapping, + start >> PAGE_SHIFT); + data_in = kmap_local_page(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) { + if (nr_pages == nr_dest_pages) { + ret = -E2BIG; + goto out; + } + out_page = alloc_page(GFP_NOFS); + if (out_page == NULL) { + ret = -ENOMEM; + goto out; + } + cpage_out = page_address(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 */ + if (nr_pages == nr_dest_pages) { + ret = -E2BIG; + goto out; + } + out_page = alloc_page(GFP_NOFS); + if (out_page == NULL) { + ret = -ENOMEM; + goto out; + } + cpage_out = page_address(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 (data_in) { + kunmap_local(data_in); + 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; + + data_in = kmap_local_page(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_local(data_in); + 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, + total_out - buf_start, cb, buf_start); + 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_local(data_in); + page_in_index++; + if (page_in_index >= total_pages_in) { + data_in = NULL; + break; + } + data_in = kmap_local_page(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_local(data_in); + if (!ret) + zero_fill_bio(cb->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; + + 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); + + memcpy_to_page(dest_page, pg_offset, + workspace->buf + buf_offset, bytes); + + 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) { + memzero_page(dest_page, pg_offset, destlen - pg_offset); + } + return ret; +} + +const struct btrfs_compress_op btrfs_zlib_compress = { + .workspace_manager = &wsm, + .max_level = 9, + .default_level = BTRFS_ZLIB_DEFAULT_LEVEL, +}; |