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-rw-r--r--fs/btrfs/lzo.c499
1 files changed, 499 insertions, 0 deletions
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
new file mode 100644
index 000000000..b6a4cc178
--- /dev/null
+++ b/fs/btrfs/lzo.c
@@ -0,0 +1,499 @@
+// 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, followd 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 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);
+}
+
+static struct list_head *lzo_alloc_workspace(void)
+{
+ 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);
+}
+
+static 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;
+}
+
+static 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;
+}
+
+static 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;
+}
+
+static void lzo_set_level(struct list_head *ws, unsigned int type)
+{
+}
+
+const struct btrfs_compress_op btrfs_lzo_compress = {
+ .alloc_workspace = lzo_alloc_workspace,
+ .free_workspace = lzo_free_workspace,
+ .compress_pages = lzo_compress_pages,
+ .decompress_bio = lzo_decompress_bio,
+ .decompress = lzo_decompress,
+ .set_level = lzo_set_level,
+};
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