Re: [PATCH 1/4] fs: do not drop inode_lock in dispose_list

[Christoph Hellwig <hch@lst.de>]

On Mon, Oct 25, 2010 at 04:46:11PM +1100, Dave Chinner wrote:
> Not sure whether it's my merge, something in Al's tree series or
> something brought in from the post-2.6.36 tree, but it goes splat
> pretty quickly (xfstest 013) with:

That's because the version of the separate wb and lru lists patch that
Al took from your tree was missing various deletions from the wb list.

Below is the fix I sent him, not sure why it didn't make it to the list:

Index: linux-2.6/fs/inode.c
===================================================================
--- linux-2.6.orig/fs/inode.c	2010-10-24 16:30:07.592253652 +0200
+++ linux-2.6/fs/inode.c	2010-10-24 16:31:31.132003756 +0200
@@ -509,8 +509,14 @@ static int invalidate_list(struct list_h
 			continue;
 		}
 
-		list_move(&inode->i_lru, dispose);
 		inode->i_state |= I_FREEING;
+
+		/*
+		 * Move the inode off the IO lists and LRU once I_FREEING is
+		 * set so that it won't get moved back on there if it is dirty.
+		 */
+		list_move(&inode->i_lru, dispose);
+		list_del_init(&inode->i_wb_list);
 		if (!(inode->i_state & (I_DIRTY | I_SYNC)))
 			percpu_counter_dec(&nr_inodes_unused);
 	}
@@ -620,9 +626,15 @@ static void prune_icache(int nr_to_scan)
 			if (!can_unuse(inode))
 				continue;
 		}
-		list_move(&inode->i_lru, &freeable);
 		WARN_ON(inode->i_state & I_NEW);
 		inode->i_state |= I_FREEING;
+
+		/*
+		 * Move the inode off the IO lists and LRU once I_FREEING is
+		 * set so that it won't get moved back on there if it is dirty.
+		 */
+		list_move(&inode->i_lru, &freeable);
+		list_del_init(&inode->i_wb_list);
 		percpu_counter_dec(&nr_inodes_unused);
 	}
 	if (current_is_kswapd())
@@ -1343,16 +1355,16 @@ static void iput_final(struct inode *ino
 		inode->i_state &= ~I_WILL_FREE;
 		__remove_inode_hash(inode);
 	}
-	list_del_init(&inode->i_wb_list);
+
 	WARN_ON(inode->i_state & I_NEW);
 	inode->i_state |= I_FREEING;
 
 	/*
-	 * After we delete the inode from the LRU here, we avoid moving dirty
-	 * inodes back onto the LRU now because I_FREEING is set and hence
-	 * writeback_single_inode() won't move the inode around.
+	 * Move the inode off the IO lists and LRU once I_FREEING is
+	 * set so that it won't get moved back on there if it is dirty.
 	 */
 	inode_lru_list_del(inode);
+	list_del_init(&inode->i_wb_list);
 
 	__inode_sb_list_del(inode);
 	spin_unlock(&inode_lock);