* [f2fs-dev] [PATCH] f2fs: fix to update user block counts in block_operations()
@ 2024-06-06 9:54 Chao Yu
2024-06-24 17:53 ` Jaegeuk Kim
0 siblings, 1 reply; 3+ messages in thread
From: Chao Yu @ 2024-06-06 9:54 UTC (permalink / raw)
To: jaegeuk; +Cc: linux-kernel, linux-f2fs-devel
Commit 59c9081bc86e ("f2fs: allow write page cache when writting cp")
allows write() to write data to page cache during checkpoint, so block
count fields like .total_valid_block_count, .alloc_valid_block_count
and .rf_node_block_count may encounter race condition as below:
CP Thread A
- write_checkpoint
- block_operations
- f2fs_down_write(&sbi->node_change)
- __prepare_cp_block
: ckpt->valid_block_count = .total_valid_block_count
- f2fs_up_write(&sbi->node_change)
- write
- f2fs_preallocate_blocks
- f2fs_map_blocks(,F2FS_GET_BLOCK_PRE_AIO)
- f2fs_map_lock
- f2fs_down_read(&sbi->node_change)
- f2fs_reserve_new_blocks
- inc_valid_block_count
: percpu_counter_add(&sbi->alloc_valid_block_count, count)
: sbi->total_valid_block_count += count
- f2fs_up_read(&sbi->node_change)
- do_checkpoint
: sbi->last_valid_block_count = sbi->total_valid_block_count
: percpu_counter_set(&sbi->alloc_valid_block_count, 0)
: percpu_counter_set(&sbi->rf_node_block_count, 0)
- fsync
- need_do_checkpoint
- f2fs_space_for_roll_forward
: alloc_valid_block_count was reset to zero,
so, it may missed last data during checkpoint
Let's change to update .total_valid_block_count, .alloc_valid_block_count
and .rf_node_block_count in block_operations(), then their access can be
protected by .node_change and .cp_rwsem lock, so that it can avoid above
race condition.
Fixes: 59c9081bc86e ("f2fs: allow write page cache when writting cp")
Cc: Yunlei He <heyunlei@oppo.com>
Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/f2fs/checkpoint.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 66eaad591b60..010bbd5af211 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1298,6 +1298,12 @@ static int block_operations(struct f2fs_sb_info *sbi)
* dirty node blocks and some checkpoint values by block allocation.
*/
__prepare_cp_block(sbi);
+
+ /* update user_block_counts */
+ sbi->last_valid_block_count = sbi->total_valid_block_count;
+ percpu_counter_set(&sbi->alloc_valid_block_count, 0);
+ percpu_counter_set(&sbi->rf_node_block_count, 0);
+
f2fs_up_write(&sbi->node_change);
return err;
}
@@ -1575,11 +1581,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
start_blk += NR_CURSEG_NODE_TYPE;
}
- /* update user_block_counts */
- sbi->last_valid_block_count = sbi->total_valid_block_count;
- percpu_counter_set(&sbi->alloc_valid_block_count, 0);
- percpu_counter_set(&sbi->rf_node_block_count, 0);
-
/* Here, we have one bio having CP pack except cp pack 2 page */
f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
/* Wait for all dirty meta pages to be submitted for IO */
--
2.40.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [f2fs-dev] [PATCH] f2fs: fix to update user block counts in block_operations()
2024-06-06 9:54 [f2fs-dev] [PATCH] f2fs: fix to update user block counts in block_operations() Chao Yu
@ 2024-06-24 17:53 ` Jaegeuk Kim
2024-06-25 1:14 ` Chao Yu
0 siblings, 1 reply; 3+ messages in thread
From: Jaegeuk Kim @ 2024-06-24 17:53 UTC (permalink / raw)
To: Chao Yu; +Cc: linux-kernel, linux-f2fs-devel
On 06/06, Chao Yu wrote:
> Commit 59c9081bc86e ("f2fs: allow write page cache when writting cp")
> allows write() to write data to page cache during checkpoint, so block
> count fields like .total_valid_block_count, .alloc_valid_block_count
> and .rf_node_block_count may encounter race condition as below:
>
> CP Thread A
> - write_checkpoint
> - block_operations
> - f2fs_down_write(&sbi->node_change)
> - __prepare_cp_block
> : ckpt->valid_block_count = .total_valid_block_count
> - f2fs_up_write(&sbi->node_change)
> - write
> - f2fs_preallocate_blocks
> - f2fs_map_blocks(,F2FS_GET_BLOCK_PRE_AIO)
> - f2fs_map_lock
> - f2fs_down_read(&sbi->node_change)
> - f2fs_reserve_new_blocks
> - inc_valid_block_count
> : percpu_counter_add(&sbi->alloc_valid_block_count, count)
> : sbi->total_valid_block_count += count
> - f2fs_up_read(&sbi->node_change)
> - do_checkpoint
> : sbi->last_valid_block_count = sbi->total_valid_block_count
> : percpu_counter_set(&sbi->alloc_valid_block_count, 0)
> : percpu_counter_set(&sbi->rf_node_block_count, 0)
> - fsync
> - need_do_checkpoint
> - f2fs_space_for_roll_forward
> : alloc_valid_block_count was reset to zero,
> so, it may missed last data during checkpoint
>
> Let's change to update .total_valid_block_count, .alloc_valid_block_count
> and .rf_node_block_count in block_operations(), then their access can be
> protected by .node_change and .cp_rwsem lock, so that it can avoid above
> race condition.
>
> Fixes: 59c9081bc86e ("f2fs: allow write page cache when writting cp")
> Cc: Yunlei He <heyunlei@oppo.com>
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> fs/f2fs/checkpoint.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 66eaad591b60..010bbd5af211 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -1298,6 +1298,12 @@ static int block_operations(struct f2fs_sb_info *sbi)
> * dirty node blocks and some checkpoint values by block allocation.
> */
> __prepare_cp_block(sbi);
> +
> + /* update user_block_counts */
> + sbi->last_valid_block_count = sbi->total_valid_block_count;
> + percpu_counter_set(&sbi->alloc_valid_block_count, 0);
> + percpu_counter_set(&sbi->rf_node_block_count, 0);
Need to add this in __prepare_cp_block()?
> +
> f2fs_up_write(&sbi->node_change);
> return err;
> }
> @@ -1575,11 +1581,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> start_blk += NR_CURSEG_NODE_TYPE;
> }
>
> - /* update user_block_counts */
> - sbi->last_valid_block_count = sbi->total_valid_block_count;
> - percpu_counter_set(&sbi->alloc_valid_block_count, 0);
> - percpu_counter_set(&sbi->rf_node_block_count, 0);
> -
> /* Here, we have one bio having CP pack except cp pack 2 page */
> f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
> /* Wait for all dirty meta pages to be submitted for IO */
> --
> 2.40.1
>
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [f2fs-dev] [PATCH] f2fs: fix to update user block counts in block_operations()
2024-06-24 17:53 ` Jaegeuk Kim
@ 2024-06-25 1:14 ` Chao Yu
0 siblings, 0 replies; 3+ messages in thread
From: Chao Yu @ 2024-06-25 1:14 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel
On 2024/6/25 1:53, Jaegeuk Kim wrote:
> On 06/06, Chao Yu wrote:
>> Commit 59c9081bc86e ("f2fs: allow write page cache when writting cp")
>> allows write() to write data to page cache during checkpoint, so block
>> count fields like .total_valid_block_count, .alloc_valid_block_count
>> and .rf_node_block_count may encounter race condition as below:
>>
>> CP Thread A
>> - write_checkpoint
>> - block_operations
>> - f2fs_down_write(&sbi->node_change)
>> - __prepare_cp_block
>> : ckpt->valid_block_count = .total_valid_block_count
>> - f2fs_up_write(&sbi->node_change)
>> - write
>> - f2fs_preallocate_blocks
>> - f2fs_map_blocks(,F2FS_GET_BLOCK_PRE_AIO)
>> - f2fs_map_lock
>> - f2fs_down_read(&sbi->node_change)
>> - f2fs_reserve_new_blocks
>> - inc_valid_block_count
>> : percpu_counter_add(&sbi->alloc_valid_block_count, count)
>> : sbi->total_valid_block_count += count
>> - f2fs_up_read(&sbi->node_change)
>> - do_checkpoint
>> : sbi->last_valid_block_count = sbi->total_valid_block_count
>> : percpu_counter_set(&sbi->alloc_valid_block_count, 0)
>> : percpu_counter_set(&sbi->rf_node_block_count, 0)
>> - fsync
>> - need_do_checkpoint
>> - f2fs_space_for_roll_forward
>> : alloc_valid_block_count was reset to zero,
>> so, it may missed last data during checkpoint
>>
>> Let's change to update .total_valid_block_count, .alloc_valid_block_count
>> and .rf_node_block_count in block_operations(), then their access can be
>> protected by .node_change and .cp_rwsem lock, so that it can avoid above
>> race condition.
>>
>> Fixes: 59c9081bc86e ("f2fs: allow write page cache when writting cp")
>> Cc: Yunlei He <heyunlei@oppo.com>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>> fs/f2fs/checkpoint.c | 11 ++++++-----
>> 1 file changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index 66eaad591b60..010bbd5af211 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -1298,6 +1298,12 @@ static int block_operations(struct f2fs_sb_info *sbi)
>> * dirty node blocks and some checkpoint values by block allocation.
>> */
>> __prepare_cp_block(sbi);
>> +
>> + /* update user_block_counts */
>> + sbi->last_valid_block_count = sbi->total_valid_block_count;
>> + percpu_counter_set(&sbi->alloc_valid_block_count, 0);
>> + percpu_counter_set(&sbi->rf_node_block_count, 0);
>
> Need to add this in __prepare_cp_block()?
Fine to me, will update in v2.
Thanks,
>
>> +
>> f2fs_up_write(&sbi->node_change);
>> return err;
>> }
>> @@ -1575,11 +1581,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>> start_blk += NR_CURSEG_NODE_TYPE;
>> }
>>
>> - /* update user_block_counts */
>> - sbi->last_valid_block_count = sbi->total_valid_block_count;
>> - percpu_counter_set(&sbi->alloc_valid_block_count, 0);
>> - percpu_counter_set(&sbi->rf_node_block_count, 0);
>> -
>> /* Here, we have one bio having CP pack except cp pack 2 page */
>> f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
>> /* Wait for all dirty meta pages to be submitted for IO */
>> --
>> 2.40.1
>>
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-06-06 9:54 [f2fs-dev] [PATCH] f2fs: fix to update user block counts in block_operations() Chao Yu
2024-06-24 17:53 ` Jaegeuk Kim
2024-06-25 1:14 ` Chao Yu
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