On Wed 17-08-16 10:11:02, Ross Zwisler wrote:
> Currently when doing a DAX hole punch with ext4 we fail to do a writeback.
> This is because the logic around filemap_write_and_wait_range() in
> ext4_punch_hole() only looks for dirty page cache pages in the radix tree,
> not for dirty DAX exceptional entries.
>
> Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Thanks. The patch looks correct, you can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Although why don't we just simplify the test below to
mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)? After all the mapping should
not have the dirty tag set if there are no pages / no entries?
Honza
> @@ -3919,7 +3919,9 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
> * Write out all dirty pages to avoid race conditions
> * Then release them.
> */
> - if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
> + if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
> + ((!dax_mapping(mapping) && mapping->nrpages) ||
> + (dax_mapping(mapping) && mapping->nrexceptional))) {
> ret = filemap_write_and_wait_range(mapping, offset,
> offset + length - 1);
> if (ret)
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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