From cdbf8897cb09b7baf2b8a7e78051a35a872b01d5 Mon Sep 17 00:00:00 2001 From: Ross Zwisler Date: Sun, 29 Jul 2018 16:59:16 -0400 Subject: dax: dax_layout_busy_page() warn on !exceptional Inodes using DAX should only ever have exceptional entries in their page caches. Make this clear by warning if the iteration in dax_layout_busy_page() ever sees a non-exceptional entry, and by adding a comment for the pagevec_release() call which only deals with struct page pointers. Signed-off-by: Ross Zwisler Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara --- fs/dax.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/dax.c b/fs/dax.c index 641192808bb6..897b51e41d8f 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -566,7 +566,8 @@ struct page *dax_layout_busy_page(struct address_space *mapping) if (index >= end) break; - if (!radix_tree_exceptional_entry(pvec_ent)) + if (WARN_ON_ONCE( + !radix_tree_exceptional_entry(pvec_ent))) continue; xa_lock_irq(&mapping->i_pages); @@ -578,6 +579,13 @@ struct page *dax_layout_busy_page(struct address_space *mapping) if (page) break; } + + /* + * We don't expect normal struct page entries to exist in our + * tree, but we keep these pagevec calls so that this code is + * consistent with the common pattern for handling pagevecs + * throughout the kernel. + */ pagevec_remove_exceptionals(&pvec); pagevec_release(&pvec); index++; -- cgit v1.2.3