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/lzo.c | 101 ++++----------------------------------------------------- 1 file changed, 6 insertions(+), 95 deletions(-) (limited to 'fs/btrfs/lzo.c') diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index 523b144e2aec..cc9b450399df 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -260,12 +260,10 @@ static int lzo_decompress_biovec(struct list_head *ws, size_t srclen) { struct workspace *workspace = list_entry(ws, struct workspace, list); - int ret = 0; + int ret = 0, ret2; 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; @@ -273,9 +271,6 @@ static int lzo_decompress_biovec(struct list_head *ws, 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; @@ -295,8 +290,6 @@ static int lzo_decompress_biovec(struct list_head *ws, 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) { @@ -359,97 +352,15 @@ cont: 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 - */ + ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, + tot_out, disk_start, + bvec, vcnt, + &page_out_index, &pg_offset); + if (ret2 == 0) 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) -- cgit v1.2.3