return le32_to_cpu(dlen);
}
- write_compress_length(page_address(cur_page) + offset_in_page(*cur_out),
+ /*
+ * 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,
+ u32 *cur_out,
+ const u32 sectorsize)
+ {
+ u32 sector_bytes_left;
+ u32 orig_out;
+ struct page *cur_page;
++ char *kaddr;
+
+ /*
+ * 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;
+ }
+
- memcpy(page_address(cur_page) + offset_in_page(*cur_out),
++ 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);
+ 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);
+
- return 0;
++ 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)
- memset(page_address(cur_page) + offset_in_page(*cur_out), 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;
int ret = 0;
- char *data_in;
- char *cpage_out, *sizes_ptr;
- 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;
+ /* 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;
*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
+ * Skip the header for now, we will later come back and write the total
+ * compressed size
*/
- out_page = alloc_page(GFP_NOFS);
- 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);
+ 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);
- ret = lzo1x_1_compress(page_address(page_in) +
++ 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;
}
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;
+ /* 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 */
+ /* Store the size of all chunks of compressed data */
- write_compress_length(page_address(pages[0]), cur_out);
+ sizes_ptr = kmap_local_page(pages[0]);
- write_compress_length(sizes_ptr, tot_out);
++ write_compress_length(sizes_ptr, cur_out);
+ kunmap_local(sizes_ptr);
ret = 0;
- *total_out = tot_out;
- *total_in = tot_in;
+ *total_out = cur_out;
+ *total_in = cur_in - start;
out:
- *out_pages = nr_pages;
- if (out_page)
- kunmap(out_page);
-
- if (in_page) {
- kunmap(in_page);
- put_page(in_page);
- }
-
+ *out_pages = DIV_ROUND_UP(cur_out, PAGE_SIZE);
return ret;
}
git.samba.org / sfrench / cifs-2.6.git / commitdiff