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authorDavid Howells <dhowells@redhat.com>2009-04-03 16:42:35 +0100
committerDavid Howells <dhowells@redhat.com>2009-04-03 16:42:35 +0100
commit03fb3d2af96c2783c3a5bc03f3d984cf422f0e69 (patch)
tree6618f82f8be26ba2c7ac38d6e6e16befc8e1140f
parent8f0aa2f25b31ba27db84259141e52ee6ec0d2820 (diff)
downloadconfigs-03fb3d2af96c2783c3a5bc03f3d984cf422f0e69.tar.gz
FS-Cache: Release page->private after failed readahead
The attached patch causes read_cache_pages() to release page-private data on a page for which add_to_page_cache() fails. If the filler function fails, then the problematic page is left attached to the pagecache (with appropriate flags set, one presumes) and the remaining to-be-attached pages are invalidated and discarded. This permits pages with caching references associated with them to be cleaned up. The invalidatepage() address space op is called (indirectly) to do the honours. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
-rw-r--r--include/linux/page-flags.h2
-rw-r--r--mm/readahead.c39
2 files changed, 38 insertions, 3 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 61df1779b2a..9d99e7471ad 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -182,7 +182,7 @@ static inline int TestClearPage##uname(struct page *page) { return 0; }
struct page; /* forward declaration */
-TESTPAGEFLAG(Locked, locked)
+TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked)
PAGEFLAG(Error, error)
PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
diff --git a/mm/readahead.c b/mm/readahead.c
index 9ce303d4b81..6be927569cf 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -31,6 +31,41 @@ EXPORT_SYMBOL_GPL(file_ra_state_init);
#define list_to_page(head) (list_entry((head)->prev, struct page, lru))
+/*
+ * see if a page needs releasing upon read_cache_pages() failure
+ * - the caller of read_cache_pages() may have set PG_private before calling,
+ * such as the NFS fs marking pages that are cached locally on disk, thus we
+ * need to give the fs a chance to clean up in the event of an error
+ */
+static void read_cache_pages_invalidate_page(struct address_space *mapping,
+ struct page *page)
+{
+ if (PagePrivate(page)) {
+ if (!trylock_page(page))
+ BUG();
+ page->mapping = mapping;
+ do_invalidatepage(page, 0);
+ page->mapping = NULL;
+ unlock_page(page);
+ }
+ page_cache_release(page);
+}
+
+/*
+ * release a list of pages, invalidating them first if need be
+ */
+static void read_cache_pages_invalidate_pages(struct address_space *mapping,
+ struct list_head *pages)
+{
+ struct page *victim;
+
+ while (!list_empty(pages)) {
+ victim = list_to_page(pages);
+ list_del(&victim->lru);
+ read_cache_pages_invalidate_page(mapping, victim);
+ }
+}
+
/**
* read_cache_pages - populate an address space with some pages & start reads against them
* @mapping: the address_space
@@ -52,14 +87,14 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
list_del(&page->lru);
if (add_to_page_cache_lru(page, mapping,
page->index, GFP_KERNEL)) {
- page_cache_release(page);
+ read_cache_pages_invalidate_page(mapping, page);
continue;
}
page_cache_release(page);
ret = filler(data, page);
if (unlikely(ret)) {
- put_pages_list(pages);
+ read_cache_pages_invalidate_pages(mapping, pages);
break;
}
task_io_account_read(PAGE_CACHE_SIZE);