On Wed, Jan 18, 2017 at 1:02 PM, Darrick J. Wong <darrick.wong@xxxxxxxxxx> wrote: > On Wed, Jan 18, 2017 at 03:39:17PM -0500, Jeff Moyer wrote: >> Jan Kara <jack@xxxxxxx> writes: >> >> > On Tue 17-01-17 15:14:21, Vishal Verma wrote: >> >> Your note on the online repair does raise another tangentially related >> >> topic. Currently, if there are badblocks, writes via the bio submission >> >> path will clear the error (if the hardware is able to remap the bad >> >> locations). However, if the filesystem is mounted eith DAX, even >> >> non-mmap operations - read() and write() will go through the dax paths >> >> (dax_do_io()). We haven't found a good/agreeable way to perform >> >> error-clearing in this case. So currently, if a dax mounted filesystem >> >> has badblocks, the only way to clear those badblocks is to mount it >> >> without DAX, and overwrite/zero the bad locations. This is a pretty >> >> terrible user experience, and I'm hoping this can be solved in a better >> >> way. >> > >> > Please remind me, what is the problem with DAX code doing necessary work to >> > clear the error when it gets EIO from memcpy on write? >> >> You won't get an MCE for a store; only loads generate them. >> >> Won't fallocate FL_ZERO_RANGE clear bad blocks when mounted with -o dax? > > Not necessarily; XFS usually implements this by punching out the range > and then reallocating it as unwritten blocks. > That does clear the error because the unwritten blocks are zeroed and errors cleared when they become allocated again. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
