From: David Howells <dhowells@redhat.com>

Cause read_cache_pages() to release page-private data on a page for which
add_to_page_cache() fails or the filler function fails.  This permits pages
with caching references associated with them to be cleaned up.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 mm/readahead.c |   21 +++++++++++++++++++--
 1 files changed, 19 insertions(+), 2 deletions(-)

diff -puN mm/readahead.c~fs-cache-release-page-private-in-failed-readahead mm/readahead.c
--- devel/mm/readahead.c~fs-cache-release-page-private-in-failed-readahead	2006-05-12 11:37:04.000000000 -0700
+++ devel-akpm/mm/readahead.c	2006-05-12 11:37:04.000000000 -0700
@@ -14,6 +14,7 @@
 #include <linux/blkdev.h>
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
+#include <linux/buffer_head.h>
 
 void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 {
@@ -118,6 +119,22 @@ static inline unsigned long get_next_ra_
 
 #define list_to_page(head) (list_entry((head)->prev, struct page, lru))
 
+/*
+ * see if a page needs releasing upon read_cache_pages() failure
+ */
+static inline void read_cache_pages_release_page(struct address_space *mapping,
+						 struct page *page)
+{
+	if (PagePrivate(page)) {
+		page->mapping = mapping;
+		SetPageLocked(page);
+		try_to_release_page(page, GFP_KERNEL);
+		page->mapping = NULL;
+	}
+
+	page_cache_release(page);
+}
+
 /**
  * read_cache_pages - populate an address space with some pages, and
  * 			start reads against them.
@@ -142,7 +159,7 @@ int read_cache_pages(struct address_spac
 		page = list_to_page(pages);
 		list_del(&page->lru);
 		if (add_to_page_cache(page, mapping, page->index, GFP_KERNEL)) {
-			page_cache_release(page);
+			read_cache_pages_release_page(mapping, page);
 			continue;
 		}
 		ret = filler(data, page);
@@ -154,7 +171,7 @@ int read_cache_pages(struct address_spac
 
 				victim = list_to_page(pages);
 				list_del(&victim->lru);
-				page_cache_release(victim);
+				read_cache_pages_release_page(mapping, victim);
 			}
 			break;
 		}
_