The patch titled
FS-Cache: Release page->private in failed readahead
has been added to the -mm tree. Its filename is
fs-cache-release-page-private-in-failed-readahead.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: FS-Cache: Release page->private in failed readahead
From: David Howells <dhowells@xxxxxxxxxx>
The attached patch causes 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.
Further changes [try #9] that have been made:
(*) The try_to_release_page() is called instead of calling the releasepage()
op directly.
(*) The page is locked before try_to_release_page() is called.
(*) The call to try_to_release_page() and page_cache_release() have been
abstracted out into a helper function as this bit of code occurs twice..
Further changes [try #10] that have been made:
(*) The comment header on the helper function is much expanded. This states
why there's a need to call the releasepage() op in the event of an error.
(*) BUG() if the page is already locked when we try and lock it.
(*) Don't set the page mapping pointer until we've locked the page.
(*) The page is unlocked after try_to_release_page() is called.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
diff -puN mm/readahead.c~fs-cache-release-page-private-in-failed-readahead mm/readahead.c
--- a/mm/readahead.c~fs-cache-release-page-private-in-failed-readahead
+++ a/mm/readahead.c
@@ -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 +119,26 @@ 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
+ * - 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_release_page(struct address_space *mapping,
+ struct page *page)
+{
+ if (PagePrivate(page)) {
+ if (TestSetPageLocked(page))
+ BUG();
+ page->mapping = mapping;
+ try_to_release_page(page, GFP_KERNEL);
+ page->mapping = NULL;
+ unlock_page(page);
+ }
+ page_cache_release(page);
+}
+
/**
* read_cache_pages - populate an address space with some pages & start reads against them
* @mapping: the address_space
@@ -141,7 +162,7 @@ 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);
@@ -153,7 +174,7 @@ 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;
}
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
git-gfs2.patch
git-nfs.patch
binfmt_elf-consistently-use-loff_t.patch
afs-add-lock-annotations-to-afs_proc_cell_servers_startstop.patch
fs-cache-provide-a-filesystem-specific-syncable-page-bit.patch
fs-cache-generic-filesystem-caching-facility.patch
fs-cache-release-page-private-in-failed-readahead.patch
fs-cache-make-kafs-use-fs-cache.patch
nfs-use-local-caching.patch
fs-cache-cachefiles-ia64-missing-copy_page-export.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem.patch
autofs-make-sure-all-dentries-refs-are-released-before-calling-kill_anon_super.patch
vfs-destroy-the-dentries-contributed-by-a-superblock-on-unmounting.patch
ecryptfs-get_sb_dev-fix.patch
reiser4-get_sb_dev-fix.patch
mutex-subsystem-synchro-test-module.patch
-
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