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authorRoss Zwisler <ross.zwisler@linux.intel.com>2018-07-29 16:59:16 -0400
committerTheodore Ts'o <tytso@mit.edu>2018-07-29 16:59:16 -0400
commitcdbf8897cb09b7baf2b8a7e78051a35a872b01d5 (patch)
tree948dc77af5c5b9627fbe8b6fd3eb56e48556f1ef
parent0694f8c39f113bcdb759a7f84981a69bf5d7161d (diff)
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 <ross.zwisler@linux.intel.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/dax.c10
1 files changed, 9 insertions, 1 deletions
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++;