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-rw-r--r--fs/btrfs/lzo.c494
1 files changed, 494 insertions, 0 deletions
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
new file mode 100644
index 000000000..89bc5f825
--- /dev/null
+++ b/fs/btrfs/lzo.c
@@ -0,0 +1,494 @@
+// 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 ... |
+ */
+
+#define WORKSPACE_BUF_LENGTH (lzo1x_worst_compress(PAGE_SIZE))
+#define WORKSPACE_CBUF_LENGTH (lzo1x_worst_compress(PAGE_SIZE))
+
+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(WORKSPACE_BUF_LENGTH, GFP_KERNEL);
+ workspace->cbuf = kvmalloc(WORKSPACE_CBUF_LENGTH, 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_local_page(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_local(kaddr);
+
+ 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_local_page(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_local(kaddr);
+ 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_local_page(page_in);
+ ret = lzo1x_1_compress(data_in +
+ offset_in_page(cur_in), in_len,
+ workspace->cbuf, &out_len,
+ workspace->mem);
+ kunmap_local(data_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) {
+ 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];
+
+ memcpy_from_page(dest + *cur_in - orig_in, cur_page,
+ offset_in_page(*cur_in), copy_len);
+
+ *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_local_page(cb->compressed_pages[0]);
+ len_in = read_compress_length(kaddr);
+ kunmap_local(kaddr);
+ 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_local_page(cur_page);
+ seg_len = read_compress_length(kaddr + offset_in_page(cur_in));
+ kunmap_local(kaddr);
+ cur_in += LZO_LEN;
+
+ if (seg_len > WORKSPACE_CBUF_LENGTH) {
+ /*
+ * seg_len shouldn't be larger than we have allocated
+ * for workspace->cbuf
+ */
+ btrfs_err(fs_info, "unexpectedly large lzo segment len %u",
+ seg_len);
+ ret = -EIO;
+ goto out;
+ }
+
+ /* 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 = WORKSPACE_BUF_LENGTH;
+ 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,
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-12 17:25:10 +0000