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

From: Andrew Morton
Date: Tue Mar 31 2009 - 19:49:40 EST


On Mon, 30 Mar 2009 15:18:24 +0800
Wu Fengguang <fengguang.wu@xxxxxxxxx> 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@xxxxxxxxxx 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;
--
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