From 2f19cad94cee3c9bd52d0c9ca584ef506302fb7c Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Sun, 30 Nov 2014 08:56:33 -0500 Subject: btrfs: zero out left over bytes after processing compression streams Don Bailey noticed that our page zeroing for compression at end-io time isn't complete. This reworks a patch from Linus to push the zeroing into the zlib and lzo specific functions instead of trying to handle the corners inside btrfs_decompress_buf2page Signed-off-by: Chris Mason Reviewed-by: Josef Bacik Reported-by: Don A. Bailey cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds --- fs/btrfs/lzo.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'fs/btrfs/lzo.c') diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index 78285f30909e..617553cdb7d3 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -373,6 +373,8 @@ cont: } done: kunmap(pages_in[page_in_index]); + if (!ret) + btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset); return ret; } @@ -410,10 +412,23 @@ static int lzo_decompress(struct list_head *ws, unsigned char *data_in, goto out; } + /* + * the caller is already checking against PAGE_SIZE, but lets + * move this check closer to the memcpy/memset + */ + destlen = min_t(unsigned long, destlen, PAGE_SIZE); bytes = min_t(unsigned long, destlen, out_len - start_byte); kaddr = kmap_atomic(dest_page); memcpy(kaddr, workspace->buf + start_byte, bytes); + + /* + * btrfs_getblock is doing a zero on the tail of the page too, + * but this will cover anything missing from the decompressed + * data. + */ + if (bytes < destlen) + memset(kaddr+bytes, 0, destlen-bytes); kunmap_atomic(kaddr); out: return ret; -- cgit v1.2.3