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Groups > linux.kernel > #1603186 > unrolled thread

[PATCH] f2fs: protect free nid operation with cp_rwsem

Started byChao Yu <yuchao0@huawei.com>
First post2017-03-17 11:50 +0100
Last post2017-03-20 12:10 +0100
Articles 3 — 2 participants

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  [PATCH] f2fs: protect free nid operation with cp_rwsem Chao Yu <yuchao0@huawei.com> - 2017-03-17 11:50 +0100
    Re: [PATCH] f2fs: protect free nid operation with cp_rwsem Jaegeuk Kim <jaegeuk@kernel.org> - 2017-03-19 23:50 +0100
      Re: [PATCH] f2fs: protect free nid operation with cp_rwsem Chao Yu <yuchao0@huawei.com> - 2017-03-20 12:10 +0100

#1603186 — [PATCH] f2fs: protect free nid operation with cp_rwsem

FromChao Yu <yuchao0@huawei.com>
Date2017-03-17 11:50 +0100
Subject[PATCH] f2fs: protect free nid operation with cp_rwsem
Message-ID<tlXCj-535-31@gated-at.bofh.it>
- f2fs_balance_fs_bg
 - build_free_nids
  - __build_free_nids
   - scan_nat_page
    - add_free_nid
					- f2fs_create
					 - f2fs_new_inode
					  - alloc_nid
   - remove_free_nid

This patch uses cp_rwsem to protect free nid allocation/initialization
to avoid reusing allocated nid in above scenario.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/inode.c   | 2 ++
 fs/f2fs/segment.c | 5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 2520fa72b23f..f941410f994a 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -423,7 +423,9 @@ void f2fs_evict_inode(struct inode *inode)
 			add_ino_entry(sbi, inode->i_ino, UPDATE_INO);
 	}
 	if (is_inode_flag_set(inode, FI_FREE_NID)) {
+		f2fs_lock_op(sbi);
 		alloc_nid_failed(sbi, inode->i_ino);
+		f2fs_unlock_op(sbi);
 		clear_inode_flag(inode, FI_FREE_NID);
 	}
 	f2fs_bug_on(sbi, err &&
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 0bf024f62330..f85e1f443c99 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -426,8 +426,11 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
 
 	if (!available_free_memory(sbi, FREE_NIDS))
 		try_to_free_nids(sbi, MAX_FREE_NIDS);
-	else
+	else {
+		f2fs_lock_op(sbi);
 		build_free_nids(sbi, false, false);
+		f2fs_unlock_op(sbi);
+	}
 
 	if (!is_idle(sbi))
 		return;
-- 
2.8.2.295.g3f1c1d0

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#1604103

FromJaegeuk Kim <jaegeuk@kernel.org>
Date2017-03-19 23:50 +0100
Message-ID<tmRO9-3Wn-3@gated-at.bofh.it>
In reply to#1603186
Hi Chao,

On 03/17, Chao Yu wrote:
> - f2fs_balance_fs_bg
>  - build_free_nids
>   - __build_free_nids
>    - scan_nat_page
>     - add_free_nid
> 					- f2fs_create
> 					 - f2fs_new_inode
> 					  - alloc_nid
>    - remove_free_nid
> 
> This patch uses cp_rwsem to protect free nid allocation/initialization
> to avoid reusing allocated nid in above scenario.

It looks like description doesn't match to your change below?

Thanks,

> 
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
>  fs/f2fs/inode.c   | 2 ++
>  fs/f2fs/segment.c | 5 ++++-
>  2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index 2520fa72b23f..f941410f994a 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -423,7 +423,9 @@ void f2fs_evict_inode(struct inode *inode)
>  			add_ino_entry(sbi, inode->i_ino, UPDATE_INO);
>  	}
>  	if (is_inode_flag_set(inode, FI_FREE_NID)) {
> +		f2fs_lock_op(sbi);
>  		alloc_nid_failed(sbi, inode->i_ino);
> +		f2fs_unlock_op(sbi);
>  		clear_inode_flag(inode, FI_FREE_NID);
>  	}
>  	f2fs_bug_on(sbi, err &&
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0bf024f62330..f85e1f443c99 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -426,8 +426,11 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
>  
>  	if (!available_free_memory(sbi, FREE_NIDS))
>  		try_to_free_nids(sbi, MAX_FREE_NIDS);
> -	else
> +	else {
> +		f2fs_lock_op(sbi);
>  		build_free_nids(sbi, false, false);
> +		f2fs_unlock_op(sbi);
> +	}
>  
>  	if (!is_idle(sbi))
>  		return;
> -- 
> 2.8.2.295.g3f1c1d0

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#1604376

FromChao Yu <yuchao0@huawei.com>
Date2017-03-20 12:10 +0100
Message-ID<tn3mi-3Qx-23@gated-at.bofh.it>
In reply to#1604103
Hi Jaegeuk,

On 2017/3/20 6:44, Jaegeuk Kim wrote:
> Hi Chao,
> 
> On 03/17, Chao Yu wrote:
>> - f2fs_balance_fs_bg
>>  - build_free_ni
>>   - __build_free_nids
>>    - scan_nat_page
>>     - add_free_nid
>> 					- f2fs_create
>> 					 - f2fs_new_inode
>> 					  - alloc_nid
>>    - remove_free_nid
>>
>> This patch uses cp_rwsem to protect free nid allocation/initialization
>> to avoid reusing allocated nid in above scenario.
> 
> It looks like description doesn't match to your change below?

It looks like the problem will not happen because on_build_free_nids will stop
alloc_nid stealing one allocated nid while building free nids. Please ignore
this patch, sorry.

I found another potential case, could you please check that one?

Thanks,

> 
> Thanks,
> 
>>
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>>  fs/f2fs/inode.c   | 2 ++
>>  fs/f2fs/segment.c | 5 ++++-
>>  2 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>> index 2520fa72b23f..f941410f994a 100644
>> --- a/fs/f2fs/inode.c
>> +++ b/fs/f2fs/inode.c
>> @@ -423,7 +423,9 @@ void f2fs_evict_inode(struct inode *inode)
>>  			add_ino_entry(sbi, inode->i_ino, UPDATE_INO);
>>  	}
>>  	if (is_inode_flag_set(inode, FI_FREE_NID)) {
>> +		f2fs_lock_op(sbi);
>>  		alloc_nid_failed(sbi, inode->i_ino);
>> +		f2fs_unlock_op(sbi);
>>  		clear_inode_flag(inode, FI_FREE_NID);
>>  	}
>>  	f2fs_bug_on(sbi, err &&
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 0bf024f62330..f85e1f443c99 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -426,8 +426,11 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
>>  
>>  	if (!available_free_memory(sbi, FREE_NIDS))
>>  		try_to_free_nids(sbi, MAX_FREE_NIDS);
>> -	else
>> +	else {
>> +		f2fs_lock_op(sbi);
>>  		build_free_nids(sbi, false, false);
>> +		f2fs_unlock_op(sbi);
>> +	}
>>  
>>  	if (!is_idle(sbi))
>>  		return;
>> -- 
>> 2.8.2.295.g3f1c1d0
> 
> .
> 

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