From: yangerkun yangerkun@huawei.com

hulk inclusion category: bugfix bugzilla: 109297 CVE: NA ---------------------------

Our testcase(briefly described as fsstress on dm thin-provisioning which ext4 see volume size with 100G but actual size 10G) trigger a hungtask bug since ext4_writepages fall into a infinite loop:

static int ext4_writepages(xxx) { ... while (!done && mpd.first_page <= mpd.last_page) { ... ret = mpage_prepare_extent_to_map(&mpd); if (!ret) { ... ret = mpage_map_and_submit_extent(handle, &mpd,&give_up_on_write); <----- will return -ENOSPC ... } ... if (ret == -ENOSPC && sbi->s_journal) { <------ we cannot break since we will get ENOSPC forever jbd2_journal_force_commit_nested(sbi->s_journal); ret = 0; continue; } ... } }

Got ENOSPC with follow stack: ... ext4_ext_map_blocks ext4_ext_convert_to_initialized ext4_ext_zeroout ext4_issue_zeroout ... submit_bio_wait <-- bio to thinpool will return ENOSPC

Actually the ENOSPC from thin-provisioning means that a EIO from block device. We need convert the err as EIO to stop confuse ext4.

Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/ext4/inode.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 6b6b94ebbcb85..b809d383cc5ae 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -427,6 +427,9 @@ int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk, if (ret > 0) ret = 0;

+ if (ret == -ENOSPC) + ret = -EIO; + return ret; }