[PATCH] skip I_CLEAR state inodes

[Wu Fengguang <fengguang.wu@intel.com>]

Add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and
add_dquot_ref().

clear_inode() will switch inode state from I_FREEING to I_CLEAR,
and do so _outside_ of inode_lock. So any I_FREEING testing is
incomplete without the testing of I_CLEAR.

Masayoshi MIZUMA first discovered the bug in drop_pagecache_sb() and
Jan Kara reminds fixing the other two cases. Thanks!

Reported-by: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 fs/dquot.c        |    2 +-
 fs/drop_caches.c  |    2 +-
 fs/fs-writeback.c |    3 ++-
 3 files changed, 4 insertions(+), 3 deletions(-)

--- mm.orig/fs/drop_caches.c
+++ mm/fs/drop_caches.c
@@ -18,7 +18,7 @@ static void drop_pagecache_sb(struct sup
 
 	spin_lock(&inode_lock);
 	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-		if (inode->i_state & (I_FREEING|I_WILL_FREE))
+		if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
 			continue;
 		if (inode->i_mapping->nrpages == 0)
 			continue;
--- mm.orig/fs/fs-writeback.c
+++ mm/fs/fs-writeback.c
@@ -538,7 +538,8 @@ void generic_sync_sb_inodes(struct super
 		list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
 			struct address_space *mapping;
 
-			if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+			if (inode->i_state &
+					(I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
 				continue;
 			mapping = inode->i_mapping;
 			if (mapping->nrpages == 0)
--- mm.orig/fs/dquot.c
+++ mm/fs/dquot.c
@@ -793,7 +793,7 @@ static void add_dquot_ref(struct super_b
 			continue;
 		if (!dqinit_needed(inode, type))
 			continue;
-		if (inode->i_state & (I_FREEING|I_WILL_FREE))
+		if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
 			continue;
 
 		__iget(inode);