Re: [PATCH] ext4: stop return ENOSPC from ext4_issue_zeroout

On Mon, Aug 16, 2021 at 12:05:45PM +0200, Jan Kara wrote:

Yes, that looks indeed better. I'd note that even splitting extent may fail
due to ENOSPC on thin-provisioned storage but the chances are *much* lower.

Indeed, any kind of metadata update (updating an inode atime, creating
a new inode, deleting a directory entry, etc.) can fail due to ENOSPC
on thin-provision storage, leading to a potentially corrupted file
system since some writes will succeed, while others won't --- and
that's not a scenario that's super well tested, nor is there much we
can do other than remounting the file system read/only or forcing a
reboot.

But at least we won't throw the kernel into an infinite loop, which is
what yangerkun was reporting...

					- Ted