btrfs: Extract duplicate decompress code
Add a common function to copy decompressed data from working buffer
to bio pages.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 9a3e693..f5ec2d4 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -218,24 +218,16 @@
size_t srclen)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
- int ret = 0;
+ int ret = 0, ret2;
int wbits = MAX_WBITS;
char *data_in;
size_t total_out = 0;
- 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;
- unsigned long bytes;
- unsigned long working_bytes;
unsigned long pg_offset;
- unsigned long start_byte;
- unsigned long current_buf_start;
- char *kaddr;
data_in = kmap(pages_in[page_in_index]);
workspace->inf_strm.next_in = data_in;
@@ -245,8 +237,6 @@
workspace->inf_strm.total_out = 0;
workspace->inf_strm.next_out = workspace->buf;
workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
- page_out = bvec[page_out_index].bv_page;
- page_bytes_left = PAGE_CACHE_SIZE;
pg_offset = 0;
/* If it's deflate, and it's got no preset dictionary, then
@@ -268,100 +258,23 @@
ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END)
break;
- /*
- * buf start is the byte offset we're of the start of
- * our workspace buffer
- */
- buf_start = total_out;
- /* total_out is the last byte of the workspace buffer */
+ buf_start = total_out;
total_out = workspace->inf_strm.total_out;
- working_bytes = total_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
- */
- if (ret != Z_STREAM_END)
- ret = -1;
+ /* we didn't make progress in this inflate call, we're done */
+ if (buf_start == total_out)
break;
+
+ ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
+ total_out, disk_start,
+ bvec, vcnt,
+ &page_out_index, &pg_offset);
+ if (ret2 == 0) {
+ ret = 0;
+ goto done;
}
- /* we haven't yet hit data corresponding to this page */
- if (total_out <= start_byte)
- goto next;
-
- /*
- * the start of the data we care about is offset into
- * the middle of our working buffer
- */
- if (total_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 (total_out <= start_byte)
- goto next;
-
- /* 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 (total_out > start_byte &&
- current_buf_start < start_byte) {
- buf_offset = start_byte - buf_start;
- working_bytes = total_out - start_byte;
- current_buf_start = buf_start +
- buf_offset;
- }
- }
- }
-next:
workspace->inf_strm.next_out = workspace->buf;
workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;