Hi Weiwen, On Mon, Jan 18, 2021 at 08:39:45PM +0800, Hu Weiwen wrote: > When __erofs_battach() is called on an buffer block of which > (bb->buffers.off % EROFS_BLKSIZ == 0), `tail_blkaddr' will not be > updated correctly. This bug can be reproduced by: > > mkdir bug-repo > head -c 4032 /dev/urandom > bug-repo/1 > head -c 4095 /dev/urandom > bug-repo/2 > head -c 12345 /dev/urandom > bug-repo/3 # arbitrary size > mkfs.erofs -Eforce-inode-compact bug-repo.erofs.img bug-repo > > Then mount this image and see that file `3' in the image is different > from `bug-repo/3'. > > This patch fix this by: > > * Don't inline tail-end data in this case, since the tail-end data will > be in a different block from inode. > * Correctly handle `battach' in this case. >
I will evaluate this condition later, yet if you have some interest and extra time, could you also help on writing a regression testcase for this, so we can look after such regression in case of the future code changes? This is also an ongoing work for the next erofs-utils release, see: https://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git/ Thanks, Gao Xiang
