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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /fs/btrfs/lzo.c | |
parent | Initial commit. (diff) | |
download | linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/btrfs/lzo.c')
-rw-r--r-- | fs/btrfs/lzo.c | 489 |
1 files changed, 489 insertions, 0 deletions
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c new file mode 100644 index 000000000..aa9cd11f4 --- /dev/null +++ b/fs/btrfs/lzo.c @@ -0,0 +1,489 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2008 Oracle. All rights reserved. + */ + +#include <linux/kernel.h> +#include <linux/slab.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/lzo.h> +#include <linux/refcount.h> +#include "compression.h" + +#define LZO_LEN 4 + +/* + * Btrfs LZO compression format + * + * Regular and inlined LZO compressed data extents consist of: + * + * 1. Header + * Fixed size. LZO_LEN (4) bytes long, LE32. + * Records the total size (including the header) of compressed data. + * + * 2. Segment(s) + * Variable size. Each segment includes one segment header, followed by data + * payload. + * One regular LZO compressed extent can have one or more segments. + * For inlined LZO compressed extent, only one segment is allowed. + * One segment represents at most one page of uncompressed data. + * + * 2.1 Segment header + * Fixed size. LZO_LEN (4) bytes long, LE32. + * Records the total size of the segment (not including the header). + * Segment header never crosses page boundary, thus it's possible to + * have at most 3 padding zeros at the end of the page. + * + * 2.2 Data Payload + * Variable size. Size up limit should be lzo1x_worst_compress(PAGE_SIZE) + * which is 4419 for a 4KiB page. + * + * Example: + * Page 1: + * 0 0x2 0x4 0x6 0x8 0xa 0xc 0xe 0x10 + * 0x0000 | Header | SegHdr 01 | Data payload 01 ... | + * ... + * 0x0ff0 | SegHdr N | Data payload N ... |00| + * ^^ padding zeros + * Page 2: + * 0x1000 | SegHdr N+1| Data payload N+1 ... | + */ + +struct workspace { + void *mem; + void *buf; /* where decompressed data goes */ + void *cbuf; /* where compressed data goes */ + struct list_head list; +}; + +static struct workspace_manager wsm; + +void lzo_free_workspace(struct list_head *ws) +{ + struct workspace *workspace = list_entry(ws, struct workspace, list); + + kvfree(workspace->buf); + kvfree(workspace->cbuf); + kvfree(workspace->mem); + kfree(workspace); +} + +struct list_head *lzo_alloc_workspace(unsigned int level) +{ + struct workspace *workspace; + + workspace = kzalloc(sizeof(*workspace), GFP_KERNEL); + if (!workspace) + return ERR_PTR(-ENOMEM); + + workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL); + workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL); + workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL); + if (!workspace->mem || !workspace->buf || !workspace->cbuf) + goto fail; + + INIT_LIST_HEAD(&workspace->list); + + return &workspace->list; +fail: + lzo_free_workspace(&workspace->list); + return ERR_PTR(-ENOMEM); +} + +static inline void write_compress_length(char *buf, size_t len) +{ + __le32 dlen; + + dlen = cpu_to_le32(len); + memcpy(buf, &dlen, LZO_LEN); +} + +static inline size_t read_compress_length(const char *buf) +{ + __le32 dlen; + + memcpy(&dlen, buf, LZO_LEN); + return le32_to_cpu(dlen); +} + +int lzo_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 = 0; + 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 long len = *total_out; + unsigned long nr_dest_pages = *out_pages; + const unsigned long max_out = nr_dest_pages * PAGE_SIZE; + size_t in_len; + size_t out_len; + char *buf; + unsigned long tot_in = 0; + unsigned long tot_out = 0; + unsigned long pg_bytes_left; + unsigned long out_offset; + unsigned long bytes; + + *out_pages = 0; + *total_out = 0; + *total_in = 0; + + in_page = find_get_page(mapping, start >> PAGE_SHIFT); + data_in = kmap(in_page); + + /* + * store the size of all chunks of compressed data in + * the first 4 bytes + */ + out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); + if (out_page == NULL) { + ret = -ENOMEM; + goto out; + } + cpage_out = kmap(out_page); + out_offset = LZO_LEN; + tot_out = LZO_LEN; + pages[0] = out_page; + nr_pages = 1; + pg_bytes_left = PAGE_SIZE - LZO_LEN; + + /* compress at most one page of data each time */ + in_len = min(len, PAGE_SIZE); + while (tot_in < len) { + ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf, + &out_len, workspace->mem); + if (ret != LZO_E_OK) { + pr_debug("BTRFS: lzo in loop returned %d\n", + ret); + ret = -EIO; + goto out; + } + + /* store the size of this chunk of compressed data */ + write_compress_length(cpage_out + out_offset, out_len); + tot_out += LZO_LEN; + out_offset += LZO_LEN; + pg_bytes_left -= LZO_LEN; + + tot_in += in_len; + tot_out += out_len; + + /* copy bytes from the working buffer into the pages */ + buf = workspace->cbuf; + while (out_len) { + bytes = min_t(unsigned long, pg_bytes_left, out_len); + + memcpy(cpage_out + out_offset, buf, bytes); + + out_len -= bytes; + pg_bytes_left -= bytes; + buf += bytes; + out_offset += bytes; + + /* + * we need another page for writing out. + * + * Note if there's less than 4 bytes left, we just + * skip to a new page. + */ + if ((out_len == 0 && pg_bytes_left < LZO_LEN) || + pg_bytes_left == 0) { + if (pg_bytes_left) { + memset(cpage_out + out_offset, 0, + pg_bytes_left); + tot_out += pg_bytes_left; + } + + /* we're done, don't allocate new page */ + if (out_len == 0 && tot_in >= len) + break; + + 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; + + pg_bytes_left = PAGE_SIZE; + out_offset = 0; + } + } + + /* we're making it bigger, give up */ + if (tot_in > 8192 && tot_in < tot_out) { + ret = -E2BIG; + goto out; + } + + /* we're all done */ + if (tot_in >= len) + break; + + if (tot_out > max_out) + break; + + bytes_left = len - tot_in; + kunmap(in_page); + put_page(in_page); + + start += PAGE_SIZE; + in_page = find_get_page(mapping, start >> PAGE_SHIFT); + data_in = kmap(in_page); + in_len = min(bytes_left, PAGE_SIZE); + } + + if (tot_out >= tot_in) { + ret = -E2BIG; + goto out; + } + + /* store the size of all chunks of compressed data */ + cpage_out = kmap(pages[0]); + write_compress_length(cpage_out, tot_out); + + kunmap(pages[0]); + + ret = 0; + *total_out = tot_out; + *total_in = tot_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 lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) +{ + struct workspace *workspace = list_entry(ws, struct workspace, list); + int ret = 0, ret2; + char *data_in; + 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; + unsigned long buf_offset = 0; + unsigned long bytes; + unsigned long working_bytes; + size_t in_len; + size_t out_len; + const size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE); + unsigned long in_offset; + unsigned long in_page_bytes_left; + unsigned long tot_in; + unsigned long tot_out; + unsigned long tot_len; + char *buf; + bool may_late_unmap, need_unmap; + struct page **pages_in = cb->compressed_pages; + u64 disk_start = cb->start; + struct bio *orig_bio = cb->orig_bio; + + data_in = kmap(pages_in[0]); + tot_len = read_compress_length(data_in); + /* + * Compressed data header check. + * + * The real compressed size can't exceed the maximum extent length, and + * all pages should be used (whole unused page with just the segment + * header is not possible). If this happens it means the compressed + * extent is corrupted. + */ + if (tot_len > min_t(size_t, BTRFS_MAX_COMPRESSED, srclen) || + tot_len < srclen - PAGE_SIZE) { + ret = -EUCLEAN; + goto done; + } + + tot_in = LZO_LEN; + in_offset = LZO_LEN; + in_page_bytes_left = PAGE_SIZE - LZO_LEN; + + tot_out = 0; + + while (tot_in < tot_len) { + in_len = read_compress_length(data_in + in_offset); + in_page_bytes_left -= LZO_LEN; + in_offset += LZO_LEN; + tot_in += LZO_LEN; + + /* + * Segment header check. + * + * The segment length must not exceed the maximum LZO + * compression size, nor the total compressed size. + */ + if (in_len > max_segment_len || tot_in + in_len > tot_len) { + ret = -EUCLEAN; + goto done; + } + + tot_in += in_len; + working_bytes = in_len; + may_late_unmap = need_unmap = false; + + /* fast path: avoid using the working buffer */ + if (in_page_bytes_left >= in_len) { + buf = data_in + in_offset; + bytes = in_len; + may_late_unmap = true; + goto cont; + } + + /* copy bytes from the pages into the working buffer */ + buf = workspace->cbuf; + buf_offset = 0; + while (working_bytes) { + bytes = min(working_bytes, in_page_bytes_left); + + memcpy(buf + buf_offset, data_in + in_offset, bytes); + buf_offset += bytes; +cont: + working_bytes -= bytes; + in_page_bytes_left -= bytes; + in_offset += bytes; + + /* check if we need to pick another page */ + if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN) + || in_page_bytes_left == 0) { + tot_in += in_page_bytes_left; + + if (working_bytes == 0 && tot_in >= tot_len) + break; + + if (page_in_index + 1 >= total_pages_in) { + ret = -EIO; + goto done; + } + + if (may_late_unmap) + need_unmap = true; + else + kunmap(pages_in[page_in_index]); + + data_in = kmap(pages_in[++page_in_index]); + + in_page_bytes_left = PAGE_SIZE; + in_offset = 0; + } + } + + out_len = max_segment_len; + ret = lzo1x_decompress_safe(buf, in_len, workspace->buf, + &out_len); + if (need_unmap) + kunmap(pages_in[page_in_index - 1]); + if (ret != LZO_E_OK) { + pr_warn("BTRFS: decompress failed\n"); + ret = -EIO; + break; + } + + buf_start = tot_out; + tot_out += out_len; + + ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, + tot_out, disk_start, orig_bio); + if (ret2 == 0) + break; + } +done: + kunmap(pages_in[page_in_index]); + if (!ret) + zero_fill_bio(orig_bio); + return ret; +} + +int lzo_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); + size_t in_len; + size_t out_len; + size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE); + int ret = 0; + char *kaddr; + unsigned long bytes; + + if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2) + return -EUCLEAN; + + in_len = read_compress_length(data_in); + if (in_len != srclen) + return -EUCLEAN; + data_in += LZO_LEN; + + in_len = read_compress_length(data_in); + if (in_len != srclen - LZO_LEN * 2) { + ret = -EUCLEAN; + goto out; + } + data_in += LZO_LEN; + + out_len = PAGE_SIZE; + ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len); + if (ret != LZO_E_OK) { + pr_warn("BTRFS: decompress failed!\n"); + ret = -EIO; + goto out; + } + + if (out_len < start_byte) { + ret = -EIO; + goto out; + } + + /* + * the caller is already checking against PAGE_SIZE, but lets + * move this check closer to the memcpy/memset + */ + destlen = min_t(unsigned long, destlen, PAGE_SIZE); + bytes = min_t(unsigned long, destlen, out_len - start_byte); + + kaddr = kmap_atomic(dest_page); + memcpy(kaddr, workspace->buf + start_byte, bytes); + + /* + * btrfs_getblock is doing a zero on the tail of the page too, + * but this will cover anything missing from the decompressed + * data. + */ + if (bytes < destlen) + memset(kaddr+bytes, 0, destlen-bytes); + kunmap_atomic(kaddr); +out: + return ret; +} + +const struct btrfs_compress_op btrfs_lzo_compress = { + .workspace_manager = &wsm, + .max_level = 1, + .default_level = 1, +}; |