[PATCH 29/45] writeback: fix the shmem AOP_WRITEPAGE_ACTIVATE case

[Wu Fengguang]

When shmem returns AOP_WRITEPAGE_ACTIVATE, the inode pages cannot be
synced in the near future. So write_cache_pages shall stop writting this
inode, and shmem shall increase pages_skipped to instruct VFS not to
busy retry.

CC: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---

---
 mm/page-writeback.c |   23 +++++++++++------------
 mm/shmem.c          |    1 +
 2 files changed, 12 insertions(+), 12 deletions(-)

--- linux.orig/mm/page-writeback.c	2009-10-06 23:39:28.000000000 +0800
+++ linux/mm/page-writeback.c	2009-10-06 23:39:29.000000000 +0800
@@ -851,19 +851,18 @@ continue_unlock:
 				if (ret == AOP_WRITEPAGE_ACTIVATE) {
 					unlock_page(page);
 					ret = 0;
-				} else {
-					/*
-					 * done_index is set past this page,
-					 * so media errors will not choke
-					 * background writeout for the entire
-					 * file. This has consequences for
-					 * range_cyclic semantics (ie. it may
-					 * not be suitable for data integrity
-					 * writeout).
-					 */
-					done = 1;
-					break;
 				}
+				/*
+				 * done_index is set past this page,
+				 * so media errors will not choke
+				 * background writeout for the entire
+				 * file. This has consequences for
+				 * range_cyclic semantics (ie. it may
+				 * not be suitable for data integrity
+				 * writeout).
+				 */
+				done = 1;
+				break;
  			}
 
 			if (nr_to_write > 0) {
--- linux.orig/mm/shmem.c	2009-10-06 23:37:40.000000000 +0800
+++ linux/mm/shmem.c	2009-10-06 23:39:29.000000000 +0800
@@ -1103,6 +1103,7 @@ unlock:
 	 */
 	swapcache_free(swap, NULL);
 redirty:
+	wbc->pages_skipped++;
 	set_page_dirty(page);
 	if (wbc->for_reclaim)
 		return AOP_WRITEPAGE_ACTIVATE;	/* Return with page locked */


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/