Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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,
+};