Fix the time ordering bug re-introduced by
writeback-fix-periodic-superblock-dirty-inode-flushing.patch.
It works by never move not-yet-expired dirty inodes from s_dirty to s_io,
*only to* move them back. The move-inodes-back-and-forth thing is a mess.
Cc: Ken Chen <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Fengguang Wu <[email protected]>
---
fs/fs-writeback.c | 40 ++++++++++++++++++++++------------------
1 file changed, 22 insertions(+), 18 deletions(-)
--- linux-2.6.23-rc2-mm2.orig/fs/fs-writeback.c
+++ linux-2.6.23-rc2-mm2/fs/fs-writeback.c
@@ -172,6 +172,23 @@ static void requeue_io(struct inode *ino
}
/*
+ * Queue expired dirty inodes for io.
+ */
+static void queue_io(struct super_block *sb,
+ unsigned long *older_than_this)
+{
+ while (!list_empty(&sb->s_dirty)) {
+ struct inode *inode = list_entry(sb->s_dirty.prev,
+ struct inode, i_list);
+ /* Was this inode dirtied too recently? */
+ if (older_than_this &&
+ time_after(inode->dirtied_when, *older_than_this))
+ break;
+ list_move(&inode->i_list, &sb->s_io);
+ }
+}
+
+/*
* Write a single inode's dirty pages and inode data out to disk.
* If `wait' is set, wait on the writeout.
*
@@ -295,10 +312,10 @@ __writeback_single_inode(struct inode *i
/*
* We're skipping this inode because it's locked, and we're not
- * doing writeback-for-data-integrity. Move it to the head of
- * s_dirty so that writeback can proceed with the other inodes
- * on s_io. We'll have another go at writing back this inode
- * when the s_dirty iodes get moved back onto s_io.
+ * doing writeback-for-data-integrity. Move it to s_more_io so
+ * that writeback can proceed with the other inodes on s_io.
+ * We'll have another go at writing back this inode when we
+ * completed a full scan of s_io.
*/
requeue_io(inode);
@@ -362,10 +379,8 @@ __writeback_single_inode(struct inode *i
static void
sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
{
- const unsigned long start = jiffies; /* livelock avoidance */
-
if (!wbc->for_kupdate || list_empty(&sb->s_io))
- list_splice_init(&sb->s_dirty, &sb->s_io);
+ queue_io(sb, wbc->older_than_this);
while (!list_empty(&sb->s_io)) {
struct inode *inode = list_entry(sb->s_io.prev,
@@ -406,17 +421,6 @@ sync_sb_inodes(struct super_block *sb, s
continue; /* blockdev has wrong queue */
}
- /* Was this inode dirtied after sync_sb_inodes was called? */
- if (time_after(inode->dirtied_when, start))
- break;
-
- /* Was this inode dirtied too recently? */
- if (wbc->older_than_this && time_after(inode->dirtied_when,
- *wbc->older_than_this)) {
- list_splice_init(&sb->s_io, sb->s_dirty.prev);
- break;
- }
-
/* Is another pdflush already flushing this queue? */
if (current_is_pdflush() && !writeback_acquire(bdi))
break;
--