mm/readahead: Handle ractl nr_pages being modified
Filesystems are not currently permitted to modify the number of pages
in the ractl. An upcoming patch to add readahead_expand() changes that
rule, so remove the check and resync the loop counter after every call
to the filesystem.
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20210420200116.3715790-1-willy@infradead.org/
Link: https://lore.kernel.org/r/20210421170923.4005574-1-willy@infradead.org/ # v2
diff --git a/mm/readahead.c b/mm/readahead.c
index 2088569..5b423ec 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -198,8 +198,6 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
for (i = 0; i < nr_to_read; i++) {
struct page *page = xa_load(&mapping->i_pages, index + i);
- BUG_ON(index + i != ractl->_index + ractl->_nr_pages);
-
if (page && !xa_is_value(page)) {
/*
* Page already present? Kick off the current batch
@@ -210,6 +208,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
* not worth getting one just for that.
*/
read_pages(ractl, &page_pool, true);
+ i = ractl->_index + ractl->_nr_pages - index - 1;
continue;
}
@@ -223,6 +222,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
gfp_mask) < 0) {
put_page(page);
read_pages(ractl, &page_pool, true);
+ i = ractl->_index + ractl->_nr_pages - index - 1;
continue;
}
if (i == nr_to_read - lookahead_size)