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read_pages bug?

PATCH Nick Piggin 1 participant 1 message Apr 30, 2006

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Memory management Page cache
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Nick Piggin

author
#0 lore raw

Speaking of read_pages(), doesn't the AOP_TRUNCATED_PAGE case cause a dangling page which can't get cleaned up because it is not on the lru (and the file has presumably already been truncated)?

(also, let's not worry about pretending we propogate errors)

Signature · 1 line
SUSE Labs, Novell Inc.
mm/readahead.c +8 -15
Index: linux-2.6/mm/readahead.c
===================================================================
@@ -164,16 +164,15 @@ int read_cache_pages(struct address_spac
 
 EXPORT_SYMBOL(read_cache_pages);
 
-static int read_pages(struct address_space *mapping, struct file *filp,
+static void read_pages(struct address_space *mapping, struct file *filp,
 		struct list_head *pages, unsigned nr_pages)
 {
 	unsigned page_idx;
 	struct pagevec lru_pvec;
-	int ret;
 
 	if (mapping->a_ops->readpages) {
-		ret = mapping->a_ops->readpages(filp, mapping, pages, nr_pages);
-		goto out;
+		mapping->a_ops->readpages(filp, mapping, pages, nr_pages);
+		return;
 	}
 
 	pagevec_init(&lru_pvec, 0);

@@ -182,19 +181,13 @@ static int read_pages(struct address_spa
 		list_del(&page->lru);
 		if (!add_to_page_cache(page, mapping,
 					page->index, GFP_KERNEL)) {
-			ret = mapping->a_ops->readpage(filp, page);
-			if (ret != AOP_TRUNCATED_PAGE) {
-				if (!pagevec_add(&lru_pvec, page))
-					__pagevec_lru_add(&lru_pvec);
-				continue;
-			} /* else fall through to release */
-		}
-		page_cache_release(page);
+			mapping->a_ops->readpage(filp, page);
+			if (!pagevec_add(&lru_pvec, page))
+				__pagevec_lru_add(&lru_pvec);
+		} else
+			page_cache_release(page);
 	}
 	pagevec_lru_add(&lru_pvec);
-	ret = 0;
-out:
-	return ret;
 }
 
 /*