afs: Fix afs_write_end() to handle short writes
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[1]. This is analogous to commit b9de313c 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 patch), so we need to set uptodate here in such a case. Also remove the assertion that was checking that the page was set uptodate since it's now set uptodate if it wasn't already a few lines above. The assertion was from when uptodate was set elsewhere. Changes: v3: Remove the handling of len exceeding the end of the page. Fixes: 3003bbd0 ("afs: Use the netfs_write_begin() helper") Reported-by:Jeff Layton <jlayton@kernel.org> Signed-off-by:
David Howells <dhowells@redhat.com> Acked-by:
Jeff Layton <jlayton@kernel.org> Reviewed-by:
Matthew Wilcox (Oracle) <willy@infradead.org> cc: Al Viro <viro@zeniv.linux.org.uk> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YMwVp268KTzTf8cN@zeniv-ca.linux.org.uk/ [1] Link: https://lore.kernel.org/r/162367682522.460125.5652091227576721609.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162391825688.1173366.3437507255136307904.stgit@warthog.procyon.org.uk/ # v2
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