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Date: Wed, 11 Dec 2019 09:42:04 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Jaegeuk Kim <jaegeuk@...nel.org>
CC: <linux-kernel@...r.kernel.org>,
<linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH 6/6] f2fs: set I_LINKABLE early to avoid wrong
access by vfs
On 2019/12/11 9:31, Jaegeuk Kim wrote:
> On 12/11, Chao Yu wrote:
>> On 2019/12/11 9:21, Jaegeuk Kim wrote:
>>> On 12/10, Chao Yu wrote:
>>>> On 2019/12/10 6:23, Jaegeuk Kim wrote:
>>>>> This patch moves setting I_LINKABLE early in rename2(whiteout) to avoid the
>>>>> below warning.
>>>>>
>>>>> [ 3189.163385] WARNING: CPU: 3 PID: 59523 at fs/inode.c:358 inc_nlink+0x32/0x40
>>>>> [ 3189.246979] Call Trace:
>>>>> [ 3189.248707] f2fs_init_inode_metadata+0x2d6/0x440 [f2fs]
>>>>> [ 3189.251399] f2fs_add_inline_entry+0x162/0x8c0 [f2fs]
>>>>> [ 3189.254010] f2fs_add_dentry+0x69/0xe0 [f2fs]
>>>>> [ 3189.256353] f2fs_do_add_link+0xc5/0x100 [f2fs]
>>>>> [ 3189.258774] f2fs_rename2+0xabf/0x1010 [f2fs]
>>>>> [ 3189.261079] vfs_rename+0x3f8/0xaa0
>>>>> [ 3189.263056] ? tomoyo_path_rename+0x44/0x60
>>>>> [ 3189.265283] ? do_renameat2+0x49b/0x550
>>>>> [ 3189.267324] do_renameat2+0x49b/0x550
>>>>> [ 3189.269316] __x64_sys_renameat2+0x20/0x30
>>>>> [ 3189.271441] do_syscall_64+0x5a/0x230
>>>>> [ 3189.273410] entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>>>> [ 3189.275848] RIP: 0033:0x7f270b4d9a49
>>>>>
>>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>>>>> ---
>>>>> fs/f2fs/namei.c | 27 +++++++++++++--------------
>>>>> 1 file changed, 13 insertions(+), 14 deletions(-)
>>>>>
>>>>> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
>>>>> index a1c507b0b4ac..5d9584281935 100644
>>>>> --- a/fs/f2fs/namei.c
>>>>> +++ b/fs/f2fs/namei.c
>>>>> @@ -797,6 +797,7 @@ static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry,
>>>>>
>>>>> if (whiteout) {
>>>>> f2fs_i_links_write(inode, false);
>>>>> + inode->i_state |= I_LINKABLE;
>>>>> *whiteout = inode;
>>>>> } else {
>>>>> d_tmpfile(dentry, inode);
>>>>> @@ -867,6 +868,12 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>>> F2FS_I(old_dentry->d_inode)->i_projid)))
>>>>> return -EXDEV;
>>>>>
>>>>> + if (flags & RENAME_WHITEOUT) {
>>>>> + err = f2fs_create_whiteout(old_dir, &whiteout);
>>>>> + if (err)
>>>>> + return err;
>>>>> + }
>>>>
>>>> To record quota info correctly, we need to create whiteout inode after
>>>> dquot_initialize(old_dir)?
>>>
>>> __f2fs_tmpfile() will do it.
>>
>> Okay.
>>
>> Any comments on below question?
>>
>>>
>>>>
>>>>> +
>>>>> err = dquot_initialize(old_dir);
>>>>> if (err)
>>>>> goto out;
>>>>> @@ -898,17 +905,11 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>>> }
>>>>> }
>>>>>
>>>>> - if (flags & RENAME_WHITEOUT) {
>>>>> - err = f2fs_create_whiteout(old_dir, &whiteout);
>>>>> - if (err)
>>>>> - goto out_dir;
>>>>> - }
>>>>> -
>>>>> if (new_inode) {
>>>>>
>>>>> err = -ENOTEMPTY;
>>>>> if (old_dir_entry && !f2fs_empty_dir(new_inode))
>>>>> - goto out_whiteout;
>>>>> + goto out_dir;
>>>>>
>>>>> err = -ENOENT;
>>>>> new_entry = f2fs_find_entry(new_dir, &new_dentry->d_name,
>>>>> @@ -916,7 +917,7 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>>> if (!new_entry) {
>>>>> if (IS_ERR(new_page))
>>>>> err = PTR_ERR(new_page);
>>>>> - goto out_whiteout;
>>>>> + goto out_dir;
>>>>> }
>>>>>
>>>>> f2fs_balance_fs(sbi, true);
>>>>> @@ -948,7 +949,7 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>>> err = f2fs_add_link(new_dentry, old_inode);
>>>>> if (err) {
>>>>> f2fs_unlock_op(sbi);
>>>>> - goto out_whiteout;
>>>>> + goto out_dir;
>>>>> }
>>>>>
>>>>> if (old_dir_entry)
>>>>> @@ -972,7 +973,7 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>>> if (IS_ERR(old_page))
>>>>> err = PTR_ERR(old_page);
>>>>> f2fs_unlock_op(sbi);
>>>>> - goto out_whiteout;
>>>>> + goto out_dir;
>>>>> }
>>>>> }
>>>>> }
>>>>> @@ -991,7 +992,6 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>>> f2fs_delete_entry(old_entry, old_page, old_dir, NULL);
>>>>>
>>>>> if (whiteout) {
>>>>> - whiteout->i_state |= I_LINKABLE;
>>>>> set_inode_flag(whiteout, FI_INC_LINK);
>>>>> err = f2fs_add_link(old_dentry, whiteout);
>>>>
>>>> [ 3189.256353] f2fs_do_add_link+0xc5/0x100 [f2fs]
>>>> [ 3189.258774] f2fs_rename2+0xabf/0x1010 [f2fs]
>>>>
>>>> Does the call stack point here? if so, we have set I_LINKABLE before
>>>> f2fs_add_link(), why the warning still be triggered?
>>
>> Am I missing something?
>
> Not sure exactly tho, I suspect some races before/after unlock_new_inode().
Alright, I doubt some races on whiteout->i_state updating, as we set I_LINKABLE
w/o holding inode.i_lock.
Could you have a try with holding i_lock?
Thanks,
>
>>
>> Thanks,
>>
>>>>
>>>> Thanks,
>>>>
>>>>> if (err)
>>>>> @@ -1027,15 +1027,14 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>>> f2fs_unlock_op(sbi);
>>>>> if (new_page)
>>>>> f2fs_put_page(new_page, 0);
>>>>> -out_whiteout:
>>>>> - if (whiteout)
>>>>> - iput(whiteout);
>>>>> out_dir:
>>>>> if (old_dir_entry)
>>>>> f2fs_put_page(old_dir_page, 0);
>>>>> out_old:
>>>>> f2fs_put_page(old_page, 0);
>>>>> out:
>>>>> + if (whiteout)
>>>>> + iput(whiteout);
>>>>> return err;
>>>>> }
>>>>>
>>>>>
>>> .
>>>
> .
>
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