From 3a39c18d63fec35f49df577d4b2a4e29c2212f22 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 8 Nov 2010 15:22:19 +0800 Subject: btrfs: Extract duplicate decompress code Add a common function to copy decompressed data from working buffer to bio pages. Signed-off-by: Li Zefan --- fs/btrfs/zlib.c | 111 ++++++-------------------------------------------------- 1 file changed, 12 insertions(+), 99 deletions(-) (limited to 'fs/btrfs/zlib.c') 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 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, 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 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, 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 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, 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; - } - /* 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; - } - } + 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; } -next: + workspace->inf_strm.next_out = workspace->buf; workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; -- cgit v1.1