/* * Copyright (c) 2016-present, Facebook, Inc. * 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. */ #include <linux/bio.h> #include <linux/err.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/refcount.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/zstd.h> #include "compression.h" #define ZSTD_BTRFS_MAX_WINDOWLOG 17 #define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG) #define ZSTD_BTRFS_DEFAULT_LEVEL 3 static ZSTD_parameters zstd_get_btrfs_parameters(size_t src_len) { ZSTD_parameters params = ZSTD_getParams(ZSTD_BTRFS_DEFAULT_LEVEL, src_len, 0); if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG) params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG; WARN_ON(src_len > ZSTD_BTRFS_MAX_INPUT); return params; } struct workspace { void *mem; size_t size; char *buf; struct list_head list; }; static void zstd_free_workspace(struct list_head *ws) { struct workspace *workspace = list_entry(ws, struct workspace, list); kvfree(workspace->mem); kfree(workspace->buf); kfree(workspace); } static struct list_head *zstd_alloc_workspace(void) { ZSTD_parameters params = zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT); struct workspace *workspace; workspace = kzalloc(sizeof(*workspace), GFP_KERNEL); if (!workspace) return ERR_PTR(-ENOMEM); workspace->size = max_t(size_t, ZSTD_CStreamWorkspaceBound(params.cParams), ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT)); workspace->mem = kvmalloc(workspace->size, GFP_KERNEL); workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!workspace->mem || !workspace->buf) goto fail; INIT_LIST_HEAD(&workspace->list); return &workspace->list; fail: zstd_free_workspace(&workspace->list); return ERR_PTR(-ENOMEM); } static int zstd_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); ZSTD_CStream *stream; int ret = 0; int nr_pages = 0; struct page *in_page = NULL; /* The current page to read */ struct page *out_page = NULL; /* The current page to write to */ ZSTD_inBuffer in_buf = { NULL, 0, 0 }; ZSTD_outBuffer out_buf = { NULL, 0, 0 }; unsigned long tot_in = 0; unsigned long tot_out = 0; unsigned long len = *total_out; const unsigned long nr_dest_pages = *out_pages; unsigned long max_out = nr_dest_pages * PAGE_SIZE; ZSTD_parameters params = zstd_get_btrfs_parameters(len); *out_pages = 0; *total_out = 0; *total_in = 0; /* Initialize the stream */ stream = ZSTD_initCStream(params, len, workspace->mem, workspace->size); if (!stream) { pr_warn("BTRFS: ZSTD_initCStream failed\n"); ret = -EIO; goto out; } /* map in the first page of input data */ in_page = find_get_page(mapping, start >> PAGE_SHIFT); in_buf.src = kmap(in_page); in_buf.pos = 0; in_buf.size = min_t(size_t, len, PAGE_SIZE); /* Allocate and map in the output buffer */ out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (out_page == NULL) { ret = -ENOMEM; goto out; } pages[nr_pages++] = out_page; out_buf.dst = kmap(out_page); out_buf.pos = 0; out_buf.size = min_t(size_t, max_out, PAGE_SIZE); while (1) { size_t ret2; ret2 = ZSTD_compressStream(stream, &out_buf, &in_buf); if (ZSTD_isError(ret2)) { pr_debug("BTRFS: ZSTD_compressStream returned %d\n", ZSTD_getErrorCode(ret2)); ret = -EIO; goto out; } /* Check to see if we are making it bigger */ if (tot_in + in_buf.pos > 8192 && tot_in + in_buf.pos < tot_out + out_buf.pos) { ret = -E2BIG; goto out; } /* We've reached the end of our output range */ if (out_buf.pos >= max_out) { tot_out += out_buf.pos; ret = -E2BIG; goto out; } /* Check if we need more output space */ if (out_buf.pos == out_buf.size) { tot_out += PAGE_SIZE; max_out -= PAGE_SIZE; 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; } pages[nr_pages++] = out_page; out_buf.dst = kmap(out_page); out_buf.pos = 0; out_buf.size = min_t(size_t, max_out, PAGE_SIZE); } /* We've reached the end of the input */ if (in_buf.pos >= len) { tot_in += in_buf.pos; break; } /* Check if we need more input */ if (in_buf.pos == in_buf.size) { tot_in += PAGE_SIZE; kunmap(in_page); put_page(in_page); start += PAGE_SIZE; len -= PAGE_SIZE; in_page = find_get_page(mapping, start >> PAGE_SHIFT); in_buf.src = kmap(in_page); in_buf.pos = 0; in_buf.size = min_t(size_t, len, PAGE_SIZE); } } while (1) { size_t ret2; ret2 = ZSTD_endStream(stream, &out_buf); if (ZSTD_isError(ret2)) { pr_debug("BTRFS: ZSTD_endStream returned %d\n", ZSTD_getErrorCode(ret2)); ret = -EIO; goto out; } if (ret2 == 0) { tot_out += out_buf.pos; break; } if (out_buf.pos >= max_out) { tot_out += out_buf.pos; ret = -E2BIG; goto out; } tot_out += PAGE_SIZE; max_out -= PAGE_SIZE; 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; } pages[nr_pages++] = out_page; out_buf.dst = kmap(out_page); out_buf.pos = 0; out_buf.size = min_t(size_t, max_out, PAGE_SIZE); } if (tot_out >= tot_in) { ret = -E2BIG; goto out; } ret = 0; *total_in = tot_in; *total_out = tot_out; out: *out_pages = nr_pages; /* Cleanup */ if (in_page) { kunmap(in_page); put_page(in_page); } if (out_page) kunmap(out_page); return ret; } static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) { struct workspace *workspace = list_entry(ws, struct workspace, list); struct page **pages_in = cb->compressed_pages; u64 disk_start = cb->start; struct bio *orig_bio = cb->orig_bio; size_t srclen = cb->compressed_len; ZSTD_DStream *stream; int ret = 0; unsigned long page_in_index = 0; unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); unsigned long buf_start; unsigned long total_out = 0; ZSTD_inBuffer in_buf = { NULL, 0, 0 }; ZSTD_outBuffer out_buf = { NULL, 0, 0 }; stream = ZSTD_initDStream( ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size); if (!stream) { pr_debug("BTRFS: ZSTD_initDStream failed\n"); ret = -EIO; goto done; } in_buf.src = kmap(pages_in[page_in_index]); in_buf.pos = 0; in_buf.size = min_t(size_t, srclen, PAGE_SIZE); out_buf.dst = workspace->buf; out_buf.pos = 0; out_buf.size = PAGE_SIZE; while (1) { size_t ret2; ret2 = ZSTD_decompressStream(stream, &out_buf, &in_buf); if (ZSTD_isError(ret2)) { pr_debug("BTRFS: ZSTD_decompressStream returned %d\n", ZSTD_getErrorCode(ret2)); ret = -EIO; goto done; } buf_start = total_out; total_out += out_buf.pos; out_buf.pos = 0; ret = btrfs_decompress_buf2page(out_buf.dst, buf_start, total_out, disk_start, orig_bio); if (ret == 0) break; if (in_buf.pos >= srclen) break; /* Check if we've hit the end of a frame */ if (ret2 == 0) break; if (in_buf.pos == in_buf.size) { kunmap(pages_in[page_in_index++]); if (page_in_index >= total_pages_in) { in_buf.src = NULL; ret = -EIO; goto done; } srclen -= PAGE_SIZE; in_buf.src = kmap(pages_in[page_in_index]); in_buf.pos = 0; in_buf.size = min_t(size_t, srclen, PAGE_SIZE); } } ret = 0; zero_fill_bio(orig_bio); done: if (in_buf.src) kunmap(pages_in[page_in_index]); return ret; } static int zstd_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); ZSTD_DStream *stream; int ret = 0; size_t ret2; ZSTD_inBuffer in_buf = { NULL, 0, 0 }; ZSTD_outBuffer out_buf = { NULL, 0, 0 }; unsigned long total_out = 0; unsigned long pg_offset = 0; char *kaddr; stream = ZSTD_initDStream( ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size); if (!stream) { pr_warn("BTRFS: ZSTD_initDStream failed\n"); ret = -EIO; goto finish; } destlen = min_t(size_t, destlen, PAGE_SIZE); in_buf.src = data_in; in_buf.pos = 0; in_buf.size = srclen; out_buf.dst = workspace->buf; out_buf.pos = 0; out_buf.size = PAGE_SIZE; ret2 = 1; while (pg_offset < destlen && in_buf.pos < in_buf.size) { unsigned long buf_start; unsigned long buf_offset; unsigned long bytes; /* Check if the frame is over and we still need more input */ if (ret2 == 0) { pr_debug("BTRFS: ZSTD_decompressStream ended early\n"); ret = -EIO; goto finish; } ret2 = ZSTD_decompressStream(stream, &out_buf, &in_buf); if (ZSTD_isError(ret2)) { pr_debug("BTRFS: ZSTD_decompressStream returned %d\n", ZSTD_getErrorCode(ret2)); ret = -EIO; goto finish; } buf_start = total_out; total_out += out_buf.pos; out_buf.pos = 0; if (total_out <= start_byte) continue; if (total_out > start_byte && buf_start < start_byte) buf_offset = start_byte - buf_start; else buf_offset = 0; bytes = min_t(unsigned long, destlen - pg_offset, out_buf.size - buf_offset); kaddr = kmap_atomic(dest_page); memcpy(kaddr + pg_offset, out_buf.dst + buf_offset, bytes); kunmap_atomic(kaddr); pg_offset += bytes; } ret = 0; finish: 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_zstd_compress = { .alloc_workspace = zstd_alloc_workspace, .free_workspace = zstd_free_workspace, .compress_pages = zstd_compress_pages, .decompress_bio = zstd_decompress_bio, .decompress = zstd_decompress, };