Messages in this thread | | | Date | Mon, 14 Jun 2021 14:28:14 +0100 | From | Matthew Wilcox <> | Subject | Re: [PATCH 2/3] afs: Fix afs_write_end() to handle short writes |
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On Mon, Jun 14, 2021 at 02:20:25PM +0100, David Howells wrote: > Fix afs_write_end() to correctly handle a short copy into the intended > write region of the page. Two things are necessary: > > (1) If the page is not up to date, then we should just return 0 > (ie. indicating a zero-length copy). The loop in > generic_perform_write() will go around again, possibly breaking up the > iterator into discrete chunks.
Does this actually work? What about the situation where you're reading the last page of a file and thus (almost) always reading fewer bytes than a PAGE_SIZE?
> This is analogous to commit b9de313cf05fe08fa59efaf19756ec5283af672a > for ceph. > > (2) The page should not have been set uptodate if it wasn't completely set > up by netfs_write_begin() (this will be fixed in the next page), so we > need to set PG_uptodate here in such a case.
s/page/patch/
and you have a really bad habit of breaking the layering and referring to PG_foo. Please just refer to PageFoo. Filesystems shouldn't care what the implementation of PageFoo is.
> + len = min_t(size_t, len, thp_size(page) - from); > + if (!PageUptodate(page)) { > + if (copied < len) { > + copied = 0; > + goto out; > + } > + > + SetPageUptodate(page); > + }
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