From b3ad7f39fd8561d68d1147907b38a7aad6b1828b Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Thu, 31 Aug 2023 19:29:58 +0800 Subject: erofs: ensure that the post-EOF tails are all zeroed commit e4c1cf523d820730a86cae2c6d55924833b6f7ac upstream. This was accidentally fixed up in commit e4c1cf523d82 but we can't take the full change due to other dependancy issues, so here is just the actual bugfix that is needed. [Background] keltargw reported an issue [1] that with mmaped I/Os, sometimes the tail of the last page (after file ends) is not filled with zeroes. The root cause is that such tail page could be wrongly selected for inplace I/Os so the zeroed part will then be filled with compressed data instead of zeroes. A simple fix is to avoid doing inplace I/Os for such tail parts, actually that was already fixed upstream in commit e4c1cf523d82 ("erofs: tidy up z_erofs_do_read_page()") by accident. [1] https://lore.kernel.org/r/3ad8b469-25db-a297-21f9-75db2d6ad224@linux.alibaba.com Reported-by: keltargw Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support") Signed-off-by: Gao Xiang Signed-off-by: Greg Kroah-Hartman --- fs/erofs/zdata.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs') diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index c247b1bf57cc..f6536b224586 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -716,6 +716,8 @@ hitted: cur = end - min_t(erofs_off_t, offset + end - map->m_la, end); if (!(map->m_flags & EROFS_MAP_MAPPED)) { zero_user_segment(page, cur, end); + ++spiltted; + tight = false; goto next_part; } -- cgit v1.2.3