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 'df22291ff0fd ("ext4: Retry block allocation if we have free blocks left")' add the logic to retry block allcate since we may get free block after we commit a transaction. But the ENOSPC from thin-provisioning will confuse ext4, and lead the upper infinite loop. Fix it by convert the err to EIO. Signed-off-by: yangerkun <yangerkun@xxxxxxxxxx> --- fs/ext4/inode.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 038aebd7eb2f..d9ded699a88c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -428,6 +428,9 @@ 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; } -- 2.31.1