Re: [PATCH][RESEND for 2.6.29-rc8-mm1] skip I_CLEAR state inodes

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 30 Mar 2009 15:18:24 +0800
Wu Fengguang <fengguang.wu@intel.com> wrote:

> 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 a coupled testing of I_CLEAR.
> 
> So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and
> add_dquot_ref().
> 
> Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara
> reminds fixing the other two cases.

ok...

But what is the user-visible consequence of this?  You cc'ed
stable@kernel.org so I assume it's serious.  People will want to know
what problem we're fixing!

> 
> --- 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|I_NEW))
> +		if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
>  			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/quota/dquot.c
> +++ mm/fs/quota/dquot.c
> @@ -823,7 +823,7 @@ static void add_dquot_ref(struct super_b
>  
>  	spin_lock(&inode_lock);
>  	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
> -		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;
>  		if (!atomic_read(&inode->i_writecount))
>  			continue;