| // 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" |
| #include "ctree.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 sector 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 sector boundary, thus it's possible to |
| * have at most 3 padding zeros at the end of the sector. |
| * |
| * 2.2 Data Payload |
| * Variable size. Size up limit should be lzo1x_worst_compress(sectorsize) |
| * which is 4419 for a 4KiB sectorsize. |
| * |
| * Example with 4K sectorsize: |
| * 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); |
| } |
| |
| /* |
| * Will do: |
| * |
| * - Write a segment header into the destination |
| * - Copy the compressed buffer into the destination |
| * - Make sure we have enough space in the last sector to fit a segment header |
| * If not, we will pad at most (LZO_LEN (4)) - 1 bytes of zeros. |
| * |
| * Will allocate new pages when needed. |
| */ |
| static int copy_compressed_data_to_page(char *compressed_data, |
| size_t compressed_size, |
| struct page **out_pages, |
| unsigned long max_nr_page, |
| u32 *cur_out, |
| const u32 sectorsize) |
| { |
| u32 sector_bytes_left; |
| u32 orig_out; |
| struct page *cur_page; |
| char *kaddr; |
| |
| if ((*cur_out / PAGE_SIZE) >= max_nr_page) |
| return -E2BIG; |
| |
| /* |
| * We never allow a segment header crossing sector boundary, previous |
| * run should ensure we have enough space left inside the sector. |
| */ |
| ASSERT((*cur_out / sectorsize) == (*cur_out + LZO_LEN - 1) / sectorsize); |
| |
| cur_page = out_pages[*cur_out / PAGE_SIZE]; |
| /* Allocate a new page */ |
| if (!cur_page) { |
| cur_page = alloc_page(GFP_NOFS); |
| if (!cur_page) |
| return -ENOMEM; |
| out_pages[*cur_out / PAGE_SIZE] = cur_page; |
| } |
| |
| kaddr = kmap(cur_page); |
| write_compress_length(kaddr + offset_in_page(*cur_out), |
| compressed_size); |
| *cur_out += LZO_LEN; |
| |
| orig_out = *cur_out; |
| |
| /* Copy compressed data */ |
| while (*cur_out - orig_out < compressed_size) { |
| u32 copy_len = min_t(u32, sectorsize - *cur_out % sectorsize, |
| orig_out + compressed_size - *cur_out); |
| |
| kunmap(cur_page); |
| |
| if ((*cur_out / PAGE_SIZE) >= max_nr_page) |
| return -E2BIG; |
| |
| cur_page = out_pages[*cur_out / PAGE_SIZE]; |
| /* Allocate a new page */ |
| if (!cur_page) { |
| cur_page = alloc_page(GFP_NOFS); |
| if (!cur_page) |
| return -ENOMEM; |
| out_pages[*cur_out / PAGE_SIZE] = cur_page; |
| } |
| kaddr = kmap(cur_page); |
| |
| memcpy(kaddr + offset_in_page(*cur_out), |
| compressed_data + *cur_out - orig_out, copy_len); |
| |
| *cur_out += copy_len; |
| } |
| |
| /* |
| * Check if we can fit the next segment header into the remaining space |
| * of the sector. |
| */ |
| sector_bytes_left = round_up(*cur_out, sectorsize) - *cur_out; |
| if (sector_bytes_left >= LZO_LEN || sector_bytes_left == 0) |
| goto out; |
| |
| /* The remaining size is not enough, pad it with zeros */ |
| memset(kaddr + offset_in_page(*cur_out), 0, |
| sector_bytes_left); |
| *cur_out += sector_bytes_left; |
| |
| out: |
| kunmap(cur_page); |
| return 0; |
| } |
| |
| 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); |
| const u32 sectorsize = btrfs_sb(mapping->host->i_sb)->sectorsize; |
| struct page *page_in = NULL; |
| char *sizes_ptr; |
| const unsigned long max_nr_page = *out_pages; |
| int ret = 0; |
| /* Points to the file offset of input data */ |
| u64 cur_in = start; |
| /* Points to the current output byte */ |
| u32 cur_out = 0; |
| u32 len = *total_out; |
| |
| ASSERT(max_nr_page > 0); |
| *out_pages = 0; |
| *total_out = 0; |
| *total_in = 0; |
| |
| /* |
| * Skip the header for now, we will later come back and write the total |
| * compressed size |
| */ |
| cur_out += LZO_LEN; |
| while (cur_in < start + len) { |
| char *data_in; |
| const u32 sectorsize_mask = sectorsize - 1; |
| u32 sector_off = (cur_in - start) & sectorsize_mask; |
| u32 in_len; |
| size_t out_len; |
| |
| /* Get the input page first */ |
| if (!page_in) { |
| page_in = find_get_page(mapping, cur_in >> PAGE_SHIFT); |
| ASSERT(page_in); |
| } |
| |
| /* Compress at most one sector of data each time */ |
| in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off); |
| ASSERT(in_len); |
| data_in = kmap(page_in); |
| ret = lzo1x_1_compress(data_in + |
| offset_in_page(cur_in), in_len, |
| workspace->cbuf, &out_len, |
| workspace->mem); |
| kunmap(page_in); |
| if (ret < 0) { |
| pr_debug("BTRFS: lzo in loop returned %d\n", ret); |
| ret = -EIO; |
| goto out; |
| } |
| |
| ret = copy_compressed_data_to_page(workspace->cbuf, out_len, |
| pages, max_nr_page, |
| &cur_out, sectorsize); |
| if (ret < 0) |
| goto out; |
| |
| cur_in += in_len; |
| |
| /* |
| * Check if we're making it bigger after two sectors. And if |
| * it is so, give up. |
| */ |
| if (cur_in - start > sectorsize * 2 && cur_in - start < cur_out) { |
| ret = -E2BIG; |
| goto out; |
| } |
| |
| /* Check if we have reached page boundary */ |
| if (IS_ALIGNED(cur_in, PAGE_SIZE)) { |
| put_page(page_in); |
| page_in = NULL; |
| } |
| } |
| |
| /* Store the size of all chunks of compressed data */ |
| sizes_ptr = kmap_local_page(pages[0]); |
| write_compress_length(sizes_ptr, cur_out); |
| kunmap_local(sizes_ptr); |
| |
| ret = 0; |
| *total_out = cur_out; |
| *total_in = cur_in - start; |
| out: |
| if (page_in) |
| put_page(page_in); |
| *out_pages = DIV_ROUND_UP(cur_out, PAGE_SIZE); |
| return ret; |
| } |
| |
| /* |
| * Copy the compressed segment payload into @dest. |
| * |
| * For the payload there will be no padding, just need to do page switching. |
| */ |
| static void copy_compressed_segment(struct compressed_bio *cb, |
| char *dest, u32 len, u32 *cur_in) |
| { |
| u32 orig_in = *cur_in; |
| |
| while (*cur_in < orig_in + len) { |
| char *kaddr; |
| struct page *cur_page; |
| u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in), |
| orig_in + len - *cur_in); |
| |
| ASSERT(copy_len); |
| cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE]; |
| |
| kaddr = kmap(cur_page); |
| memcpy(dest + *cur_in - orig_in, |
| kaddr + offset_in_page(*cur_in), |
| copy_len); |
| kunmap(cur_page); |
| |
| *cur_in += copy_len; |
| } |
| } |
| |
| int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) |
| { |
| struct workspace *workspace = list_entry(ws, struct workspace, list); |
| const struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb); |
| const u32 sectorsize = fs_info->sectorsize; |
| char *kaddr; |
| int ret; |
| /* Compressed data length, can be unaligned */ |
| u32 len_in; |
| /* Offset inside the compressed data */ |
| u32 cur_in = 0; |
| /* Bytes decompressed so far */ |
| u32 cur_out = 0; |
| |
| kaddr = kmap(cb->compressed_pages[0]); |
| len_in = read_compress_length(kaddr); |
| kunmap(cb->compressed_pages[0]); |
| cur_in += LZO_LEN; |
| |
| /* |
| * LZO header length check |
| * |
| * The total length should not exceed the maximum extent length, |
| * and all sectors should be used. |
| * If this happens, it means the compressed extent is corrupted. |
| */ |
| if (len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) || |
| round_up(len_in, sectorsize) < cb->compressed_len) { |
| btrfs_err(fs_info, |
| "invalid lzo header, lzo len %u compressed len %u", |
| len_in, cb->compressed_len); |
| return -EUCLEAN; |
| } |
| |
| /* Go through each lzo segment */ |
| while (cur_in < len_in) { |
| struct page *cur_page; |
| /* Length of the compressed segment */ |
| u32 seg_len; |
| u32 sector_bytes_left; |
| size_t out_len = lzo1x_worst_compress(sectorsize); |
| |
| /* |
| * We should always have enough space for one segment header |
| * inside current sector. |
| */ |
| ASSERT(cur_in / sectorsize == |
| (cur_in + LZO_LEN - 1) / sectorsize); |
| cur_page = cb->compressed_pages[cur_in / PAGE_SIZE]; |
| ASSERT(cur_page); |
| kaddr = kmap(cur_page); |
| seg_len = read_compress_length(kaddr + offset_in_page(cur_in)); |
| kunmap(cur_page); |
| cur_in += LZO_LEN; |
| |
| /* Copy the compressed segment payload into workspace */ |
| copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in); |
| |
| /* Decompress the data */ |
| ret = lzo1x_decompress_safe(workspace->cbuf, seg_len, |
| workspace->buf, &out_len); |
| if (ret != LZO_E_OK) { |
| btrfs_err(fs_info, "failed to decompress"); |
| ret = -EIO; |
| goto out; |
| } |
| |
| /* Copy the data into inode pages */ |
| ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out); |
| cur_out += out_len; |
| |
| /* All data read, exit */ |
| if (ret == 0) |
| goto out; |
| ret = 0; |
| |
| /* Check if the sector has enough space for a segment header */ |
| sector_bytes_left = sectorsize - (cur_in % sectorsize); |
| if (sector_bytes_left >= LZO_LEN) |
| continue; |
| |
| /* Skip the padding zeros */ |
| cur_in += sector_bytes_left; |
| } |
| out: |
| if (!ret) |
| zero_fill_bio(cb->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_local_page(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_local(kaddr); |
| out: |
| return ret; |
| } |
| |
| const struct btrfs_compress_op btrfs_lzo_compress = { |
| .workspace_manager = &wsm, |
| .max_level = 1, |
| .default_level = 1, |
| }; |