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-rw-r--r--fs/fs-writeback.c26
1 files changed, 22 insertions, 4 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index f81f9e71871..eed48063990 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -196,7 +196,7 @@ static void redirty_tail(struct inode *inode)
struct inode *tail_inode;
tail_inode = list_entry(sb->s_dirty.next, struct inode, i_list);
- if (!time_after_eq(inode->dirtied_when,
+ if (time_before(inode->dirtied_when,
tail_inode->dirtied_when))
inode->dirtied_when = jiffies;
}
@@ -220,6 +220,21 @@ static void inode_sync_complete(struct inode *inode)
wake_up_bit(&inode->i_state, __I_SYNC);
}
+static bool inode_dirtied_after(struct inode *inode, unsigned long t)
+{
+ bool ret = time_after(inode->dirtied_when, t);
+#ifndef CONFIG_64BIT
+ /*
+ * For inodes being constantly redirtied, dirtied_when can get stuck.
+ * It _appears_ to be in the future, but is actually in distant past.
+ * This test is necessary to prevent such wrapped-around relative times
+ * from permanently stopping the whole pdflush writeback.
+ */
+ ret = ret && time_before_eq(inode->dirtied_when, jiffies);
+#endif
+ return ret;
+}
+
/*
* Move expired dirty inodes from @delaying_queue to @dispatch_queue.
*/
@@ -231,7 +246,7 @@ static void move_expired_inodes(struct list_head *delaying_queue,
struct inode *inode = list_entry(delaying_queue->prev,
struct inode, i_list);
if (older_than_this &&
- time_after(inode->dirtied_when, *older_than_this))
+ inode_dirtied_after(inode, *older_than_this))
break;
list_move(&inode->i_list, dispatch_queue);
}
@@ -492,8 +507,11 @@ void generic_sync_sb_inodes(struct super_block *sb,
continue; /* blockdev has wrong queue */
}
- /* Was this inode dirtied after sync_sb_inodes was called? */
- if (time_after(inode->dirtied_when, start))
+ /*
+ * Was this inode dirtied after sync_sb_inodes was called?
+ * This keeps sync from extra jobs and livelock.
+ */
+ if (inode_dirtied_after(inode, start))
break;
/* Is another pdflush already flushing this queue? */