---

yaml
---
r: 45479
b: refs/heads/master
c: e3db769
h: refs/heads/master
i:
  45477: ad68513
  45475: beb9c3b
  45471: 0635de8
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 07031e14c1127fc7e1a5b98dfcc59f434e025104
+refs/heads/master: e3db7691e9f3dff3289f64e3d98583e28afe03db

trunk/Documentation/filesystems/Locking

@@ -171,6 +171,7 @@ prototypes:
 	int (*releasepage) (struct page *, int);
 	int (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
 			loff_t offset, unsigned long nr_segs);
+	int (*launder_page) (struct page *);
 
 locking rules:
 	All except set_page_dirty may block
@@ -188,6 +189,7 @@ bmap:			yes
 invalidatepage:		no	yes
 releasepage:		no	yes
 direct_IO:		no
+launder_page:		no	yes
 
 	->prepare_write(), ->commit_write(), ->sync_page() and ->readpage()
 may be called from the request handler (/dev/loop).
@@ -281,6 +283,12 @@ buffers from the page in preparation for freeing it.  It returns zero to
 indicate that the buffers are (or may be) freeable.  If ->releasepage is zero,
 the kernel assumes that the fs has no private interest in the buffers.
 
+	->launder_page() may be called prior to releasing a page if
+it is still found to be dirty. It returns zero if the page was successfully
+cleaned, or an error value if not. Note that in order to prevent the page
+getting mapped back in and redirtied, it needs to be kept locked
+across the entire operation.
+
 	Note: currently almost all instances of address_space methods are
 using BKL for internal serialization and that's one of the worst sources
 of contention. Normally they are calling library functions (in fs/buffer.c)

trunk/fs/nfs/file.c

@@ -315,14 +315,13 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
 
 static int nfs_release_page(struct page *page, gfp_t gfp)
 {
-	/*
-	 * Avoid deadlock on nfs_wait_on_request().
-	 */
-	if (!(gfp & __GFP_FS))
-		return 0;
-	/* Hack... Force nfs_wb_page() to write out the page */
-	SetPageDirty(page);
-	return !nfs_wb_page(page->mapping->host, page);
+	/* If PagePrivate() is set, then the page is not freeable */
+	return 0;
+}
+
+static int nfs_launder_page(struct page *page)
+{
+	return nfs_wb_page(page->mapping->host, page);
 }
 
 const struct address_space_operations nfs_file_aops = {
@@ -338,6 +337,7 @@ const struct address_space_operations nfs_file_aops = {
 #ifdef CONFIG_NFS_DIRECTIO
 	.direct_IO = nfs_direct_IO,
 #endif
+	.launder_page = nfs_launder_page,
 };
 
 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,

trunk/include/linux/fs.h

@@ -426,6 +426,7 @@ struct address_space_operations {
 	/* migrate the contents of a page to the specified target */
 	int (*migratepage) (struct address_space *,
 			struct page *, struct page *);
+	int (*launder_page) (struct page *);
 };
 
 struct backing_dev_info;

trunk/mm/truncate.c

@@ -341,6 +341,15 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
 	return 0;
 }
 
+static int do_launder_page(struct address_space *mapping, struct page *page)
+{
+	if (!PageDirty(page))
+		return 0;
+	if (page->mapping != mapping || mapping->a_ops->launder_page == NULL)
+		return 0;
+	return mapping->a_ops->launder_page(page);
+}
+
 /**
  * invalidate_inode_pages2_range - remove range of pages from an address_space
  * @mapping: the address_space
@@ -405,7 +414,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 					  PAGE_CACHE_SIZE, 0);
 				}
 			}
-			if (!invalidate_complete_page2(mapping, page))
+			ret = do_launder_page(mapping, page);
+			if (ret == 0 && !invalidate_complete_page2(mapping, page))
 				ret = -EIO;
 			unlock_page(page);
 		}