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fs/btrfs/zlib.c
10.5 KB
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/* * Copyright (C) 2008 Oracle. 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 v2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. * * 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/vmalloc.h> #include <linux/init.h> #include <linux/err.h> #include <linux/sched.h> #include <linux/pagemap.h> #include <linux/bio.h> |
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#include "compression.h" |
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struct workspace { |
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z_stream strm; |
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char *buf; struct list_head list; }; |
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static void zlib_free_workspace(struct list_head *ws) { struct workspace *workspace = list_entry(ws, struct workspace, list); |
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vfree(workspace->strm.workspace); |
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kfree(workspace->buf); kfree(workspace); } static struct list_head *zlib_alloc_workspace(void) |
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{ struct workspace *workspace; |
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int workspacesize; |
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workspace = kzalloc(sizeof(*workspace), GFP_NOFS); |
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if (!workspace) return ERR_PTR(-ENOMEM); |
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workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL), zlib_inflate_workspacesize()); workspace->strm.workspace = vmalloc(workspacesize); |
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workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS); |
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if (!workspace->strm.workspace || !workspace->buf) |
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goto fail; |
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INIT_LIST_HEAD(&workspace->list); |
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return &workspace->list; fail: zlib_free_workspace(&workspace->list); return ERR_PTR(-ENOMEM); |
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} |
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static int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, u64 start, unsigned long len, struct page **pages, unsigned long nr_dest_pages, unsigned long *out_pages, unsigned long *total_in, unsigned long *total_out, unsigned long max_out) |
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{ |
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struct workspace *workspace = list_entry(ws, struct workspace, list); |
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int ret; |
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char *data_in; char *cpage_out; int nr_pages = 0; struct page *in_page = NULL; struct page *out_page = NULL; |
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unsigned long bytes_left; *out_pages = 0; *total_out = 0; *total_in = 0; |
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if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) { |
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printk(KERN_WARNING "BTRFS: deflateInit failed "); |
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ret = -EIO; |
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goto out; } |
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workspace->strm.total_in = 0; workspace->strm.total_out = 0; |
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in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT); data_in = kmap(in_page); out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); |
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if (out_page == NULL) { |
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ret = -ENOMEM; |
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goto out; } |
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cpage_out = kmap(out_page); pages[0] = out_page; nr_pages = 1; |
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workspace->strm.next_in = data_in; workspace->strm.next_out = cpage_out; workspace->strm.avail_out = PAGE_CACHE_SIZE; workspace->strm.avail_in = min(len, PAGE_CACHE_SIZE); |
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while (workspace->strm.total_in < len) { ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH); |
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if (ret != Z_OK) { |
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printk(KERN_DEBUG "BTRFS: deflate in loop returned %d ", |
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ret); |
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zlib_deflateEnd(&workspace->strm); |
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ret = -EIO; |
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goto out; } /* we're making it bigger, give up */ |
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if (workspace->strm.total_in > 8192 && workspace->strm.total_in < workspace->strm.total_out) { |
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ret = -E2BIG; |
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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 */ |
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if (workspace->strm.avail_out == 0) { |
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kunmap(out_page); if (nr_pages == nr_dest_pages) { out_page = NULL; |
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ret = -E2BIG; |
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goto out; } out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); |
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if (out_page == NULL) { |
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ret = -ENOMEM; |
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goto out; } |
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cpage_out = kmap(out_page); pages[nr_pages] = out_page; nr_pages++; |
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workspace->strm.avail_out = PAGE_CACHE_SIZE; workspace->strm.next_out = cpage_out; |
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} /* we're all done */ |
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if (workspace->strm.total_in >= len) |
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break; /* we've read in a full page, get a new one */ |
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if (workspace->strm.avail_in == 0) { if (workspace->strm.total_out > max_out) |
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break; |
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bytes_left = len - workspace->strm.total_in; |
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kunmap(in_page); page_cache_release(in_page); start += PAGE_CACHE_SIZE; in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT); data_in = kmap(in_page); |
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workspace->strm.avail_in = min(bytes_left, |
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PAGE_CACHE_SIZE); |
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workspace->strm.next_in = data_in; |
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} } |
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workspace->strm.avail_in = 0; ret = zlib_deflate(&workspace->strm, Z_FINISH); zlib_deflateEnd(&workspace->strm); |
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if (ret != Z_STREAM_END) { |
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ret = -EIO; |
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goto out; } |
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if (workspace->strm.total_out >= workspace->strm.total_in) { |
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ret = -E2BIG; |
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goto out; } ret = 0; |
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*total_out = workspace->strm.total_out; *total_in = workspace->strm.total_in; |
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out: *out_pages = nr_pages; if (out_page) kunmap(out_page); if (in_page) { kunmap(in_page); page_cache_release(in_page); } |
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return ret; } |
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static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, u64 disk_start, struct bio_vec *bvec, int vcnt, size_t srclen) |
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{ |
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struct workspace *workspace = list_entry(ws, struct workspace, list); |
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int ret = 0, ret2; |
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int wbits = MAX_WBITS; |
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char *data_in; size_t total_out = 0; |
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unsigned long page_in_index = 0; unsigned long page_out_index = 0; |
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unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_CACHE_SIZE); |
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unsigned long buf_start; |
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unsigned long pg_offset; |
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data_in = kmap(pages_in[page_in_index]); |
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workspace->strm.next_in = data_in; workspace->strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE); workspace->strm.total_in = 0; |
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workspace->strm.total_out = 0; workspace->strm.next_out = workspace->buf; workspace->strm.avail_out = PAGE_CACHE_SIZE; |
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pg_offset = 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); |
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workspace->strm.next_in += 2; workspace->strm.avail_in -= 2; |
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} |
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if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { |
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printk(KERN_WARNING "BTRFS: inflateInit failed "); |
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return -EIO; |
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} |
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while (workspace->strm.total_in < srclen) { ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); |
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if (ret != Z_OK && ret != Z_STREAM_END) |
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break; |
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buf_start = total_out; |
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total_out = workspace->strm.total_out; |
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/* we didn't make progress in this inflate call, we're done */ if (buf_start == total_out) |
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break; |
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ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, total_out, disk_start, bvec, vcnt, &page_out_index, &pg_offset); if (ret2 == 0) { ret = 0; goto done; |
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} |
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workspace->strm.next_out = workspace->buf; workspace->strm.avail_out = PAGE_CACHE_SIZE; |
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if (workspace->strm.avail_in == 0) { |
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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]); |
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workspace->strm.next_in = data_in; tmp = srclen - workspace->strm.total_in; workspace->strm.avail_in = min(tmp, |
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PAGE_CACHE_SIZE); } } |
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if (ret != Z_STREAM_END) |
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ret = -EIO; |
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else |
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ret = 0; |
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done: |
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zlib_inflateEnd(&workspace->strm); |
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if (data_in) kunmap(pages_in[page_in_index]); |
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if (!ret) btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset); |
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return ret; } |
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static 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) |
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{ |
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struct workspace *workspace = list_entry(ws, struct workspace, list); |
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int ret = 0; int wbits = MAX_WBITS; |
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unsigned long bytes_left; |
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unsigned long total_out = 0; |
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unsigned long pg_offset = 0; |
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char *kaddr; |
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destlen = min_t(unsigned long, destlen, PAGE_SIZE); bytes_left = destlen; |
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workspace->strm.next_in = data_in; workspace->strm.avail_in = srclen; workspace->strm.total_in = 0; |
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workspace->strm.next_out = workspace->buf; workspace->strm.avail_out = PAGE_CACHE_SIZE; workspace->strm.total_out = 0; |
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/* 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); |
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workspace->strm.next_in += 2; workspace->strm.avail_in -= 2; |
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} |
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if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { |
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printk(KERN_WARNING "BTRFS: inflateInit failed "); |
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return -EIO; |
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} |
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while (bytes_left > 0) { |
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unsigned long buf_start; unsigned long buf_offset; unsigned long bytes; |
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ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); |
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if (ret != Z_OK && ret != Z_STREAM_END) |
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break; |
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buf_start = total_out; |
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total_out = workspace->strm.total_out; |
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if (total_out == buf_start) { |
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ret = -EIO; |
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break; } |
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if (total_out <= start_byte) |
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goto next; |
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if (total_out > start_byte && buf_start < start_byte) |
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buf_offset = start_byte - buf_start; |
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else |
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buf_offset = 0; |
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bytes = min(PAGE_CACHE_SIZE - pg_offset, PAGE_CACHE_SIZE - buf_offset); bytes = min(bytes, bytes_left); |
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kaddr = kmap_atomic(dest_page); |
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memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes); |
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kunmap_atomic(kaddr); |
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pg_offset += bytes; bytes_left -= bytes; next: |
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workspace->strm.next_out = workspace->buf; workspace->strm.avail_out = PAGE_CACHE_SIZE; |
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} |
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if (ret != Z_STREAM_END && bytes_left != 0) |
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ret = -EIO; |
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else |
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ret = 0; |
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zlib_inflateEnd(&workspace->strm); |
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/* * 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); } |
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return ret; } |
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const struct btrfs_compress_op btrfs_zlib_compress = { |
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.alloc_workspace = zlib_alloc_workspace, .free_workspace = zlib_free_workspace, .compress_pages = zlib_compress_pages, .decompress_biovec = zlib_decompress_biovec, .decompress = zlib_decompress, }; |