--- /dev/null
+/*
+ * Copyright (C) 2008 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.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 "compression.h"
+
+#define LZO_LEN 4
+
+struct workspace {
+ void *mem;
+ void *buf; /* where compressed data goes */
+ void *cbuf; /* where decompressed data goes */
+ struct list_head list;
+};
+
+static void lzo_free_workspace(struct list_head *ws)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+
+ vfree(workspace->buf);
+ vfree(workspace->cbuf);
+ vfree(workspace->mem);
+ kfree(workspace);
+}
+
+static struct list_head *lzo_alloc_workspace(void)
+{
+ struct workspace *workspace;
+
+ workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
+ if (!workspace)
+ return ERR_PTR(-ENOMEM);
+
+ workspace->mem = vmalloc(LZO1X_MEM_COMPRESS);
+ workspace->buf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
+ workspace->cbuf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
+ 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(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, unsigned long len,
+ struct page **pages,
+ unsigned long nr_dest_pages,
+ unsigned long *out_pages,
+ unsigned long *total_in,
+ unsigned long *total_out,
+ unsigned long max_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;
+
+ 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_CACHE_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_CACHE_SIZE - LZO_LEN;
+
+ /* compress at most one page of data each time */
+ in_len = min(len, PAGE_CACHE_SIZE);
+ while (tot_in < len) {
+ ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
+ &out_len, workspace->mem);
+ if (ret != LZO_E_OK) {
+ printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
+ ret);
+ ret = -1;
+ 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 = -1;
+ 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_CACHE_SIZE;
+ out_offset = 0;
+ }
+ }
+
+ /* we're making it bigger, give up */
+ if (tot_in > 8192 && tot_in < tot_out)
+ 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);
+ page_cache_release(in_page);
+
+ start += PAGE_CACHE_SIZE;
+ in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
+ data_in = kmap(in_page);
+ in_len = min(bytes_left, PAGE_CACHE_SIZE);
+ }
+
+ if (tot_out > tot_in)
+ 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);
+ page_cache_release(in_page);
+ }
+
+ return ret;
+}
+
+static int lzo_decompress_biovec(struct list_head *ws,
+ struct page **pages_in,
+ u64 disk_start,
+ struct bio_vec *bvec,
+ int vcnt,
+ size_t srclen)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ int ret = 0;
+ char *data_in;
+ unsigned long page_bytes_left;
+ unsigned long page_in_index = 0;
+ unsigned long page_out_index = 0;
+ struct page *page_out;
+ unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
+ PAGE_CACHE_SIZE;
+ unsigned long buf_start;
+ unsigned long buf_offset = 0;
+ unsigned long bytes;
+ unsigned long working_bytes;
+ unsigned long pg_offset;
+ unsigned long start_byte;
+ unsigned long current_buf_start;
+ char *kaddr;
+
+ size_t in_len;
+ size_t out_len;
+ unsigned long in_offset;
+ unsigned long in_page_bytes_left;
+ unsigned long tot_in;
+ unsigned long tot_out;
+ unsigned long tot_len;
+ char *buf;
+
+ data_in = kmap(pages_in[0]);
+ tot_len = read_compress_length(data_in);
+
+ tot_in = LZO_LEN;
+ in_offset = LZO_LEN;
+ tot_len = min_t(size_t, srclen, tot_len);
+ in_page_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
+
+ tot_out = 0;
+ page_out = bvec[0].bv_page;
+ page_bytes_left = PAGE_CACHE_SIZE;
+ pg_offset = 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;
+
+ tot_in += in_len;
+ working_bytes = in_len;
+
+ /* fast path: avoid using the working buffer */
+ if (in_page_bytes_left >= in_len) {
+ buf = data_in + in_offset;
+ bytes = in_len;
+ 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;
+
+ kunmap(pages_in[page_in_index]);
+ page_in_index++;
+ if (page_in_index >= total_pages_in) {
+ ret = -1;
+ data_in = NULL;
+ goto done;
+ }
+ data_in = kmap(pages_in[page_in_index]);
+
+ in_page_bytes_left = PAGE_CACHE_SIZE;
+ in_offset = 0;
+ }
+ }
+
+ out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
+ ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
+ &out_len);
+ if (ret != LZO_E_OK) {
+ printk(KERN_WARNING "btrfs decompress failed\n");
+ ret = -1;
+ break;
+ }
+
+ /*
+ * buf start is the byte offset we're of the start of
+ * our workspace buffer
+ */
+ buf_start = tot_out;
+
+ /* tot_out is the last byte of the workspace buffer */
+ tot_out += out_len;
+
+ working_bytes = tot_out - buf_start;
+
+ /*
+ * start_byte is the first byte of the page we're currently
+ * copying into relative to the start of the compressed data.
+ */
+ start_byte = page_offset(page_out) - disk_start;
+
+ if (working_bytes == 0) {
+ /* we didn't make progress in this inflate
+ * call, we're done
+ */
+ break;
+ }
+
+ /* we haven't yet hit data corresponding to this page */
+ if (tot_out <= start_byte)
+ continue;
+
+ /*
+ * the start of the data we care about is offset into
+ * the middle of our working buffer
+ */
+ if (tot_out > start_byte && buf_start < start_byte) {
+ buf_offset = start_byte - buf_start;
+ working_bytes -= buf_offset;
+ } else {
+ buf_offset = 0;
+ }
+ current_buf_start = buf_start;
+
+ /* copy bytes from the working buffer into the pages */
+ while (working_bytes > 0) {
+ bytes = min(PAGE_CACHE_SIZE - pg_offset,
+ PAGE_CACHE_SIZE - buf_offset);
+ bytes = min(bytes, working_bytes);
+ kaddr = kmap_atomic(page_out, KM_USER0);
+ memcpy(kaddr + pg_offset, workspace->buf + buf_offset,
+ bytes);
+ kunmap_atomic(kaddr, KM_USER0);
+ flush_dcache_page(page_out);
+
+ pg_offset += bytes;
+ page_bytes_left -= bytes;
+ buf_offset += bytes;
+ working_bytes -= bytes;
+ current_buf_start += bytes;
+
+ /* check if we need to pick another page */
+ if (page_bytes_left == 0) {
+ page_out_index++;
+ if (page_out_index >= vcnt) {
+ ret = 0;
+ goto done;
+ }
+
+ page_out = bvec[page_out_index].bv_page;
+ pg_offset = 0;
+ page_bytes_left = PAGE_CACHE_SIZE;
+ start_byte = page_offset(page_out) - disk_start;
+
+ /*
+ * make sure our new page is covered by this
+ * working buffer
+ */
+ if (tot_out <= start_byte)
+ break;
+
+ /* the next page in the biovec might not
+ * be adjacent to the last page, but it
+ * might still be found inside this working
+ * buffer. bump our offset pointer
+ */
+ if (tot_out > start_byte &&
+ current_buf_start < start_byte) {
+ buf_offset = start_byte - buf_start;
+ working_bytes = tot_out - start_byte;
+ current_buf_start = buf_start +
+ buf_offset;
+ }
+ }
+ }
+ }
+done:
+ if (data_in)
+ kunmap(pages_in[page_in_index]);
+ 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 tot_len;
+ int ret = 0;
+ char *kaddr;
+ unsigned long bytes;
+
+ BUG_ON(srclen < LZO_LEN);
+
+ tot_len = read_compress_length(data_in);
+ data_in += LZO_LEN;
+
+ in_len = read_compress_length(data_in);
+ data_in += LZO_LEN;
+
+ out_len = PAGE_CACHE_SIZE;
+ ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
+ if (ret != LZO_E_OK) {
+ printk(KERN_WARNING "btrfs decompress failed!\n");
+ ret = -1;
+ goto out;
+ }
+
+ if (out_len < start_byte) {
+ ret = -1;
+ goto out;
+ }
+
+ bytes = min_t(unsigned long, destlen, out_len - start_byte);
+
+ kaddr = kmap_atomic(dest_page, KM_USER0);
+ memcpy(kaddr, workspace->buf + start_byte, bytes);
+ kunmap_atomic(kaddr, KM_USER0);
+out:
+ return ret;
+}
+
+struct btrfs_compress_op btrfs_lzo_compress = {
+ .alloc_workspace = lzo_alloc_workspace,
+ .free_workspace = lzo_free_workspace,
+ .compress_pages = lzo_compress_pages,
+ .decompress_biovec = lzo_decompress_biovec,
+ .decompress = lzo_decompress,
+};
git.openpandora.org / pandora-kernel.git / commitdiff