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* [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
       [not found] <CGME20211101054217epcas1p3c695f37ab925f47156bd45e3adb5ed94@epcas1p3.samsung.com>
@ 2021-11-01  5:42   ` Hyeong-Jun Kim
  0 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  5:42 UTC (permalink / raw)
  To: Jaegeuk Kim, Chao Yu; +Cc: Hyeong-Jun Kim, linux-f2fs-devel, linux-kernel

Encrypted pages during GC are read and cached in META_MAPPING.
However, due to cached pages in META_MAPPING, there is an issue where
newly written pages are lost by IPU or DIO writes.

Thread A                              Thread B
- f2fs_gc(): blk 0x10 -> 0x20 (a)
                                      - IPU or DIO write on blk 0x20 (b)
- f2fs_gc(): blk 0x20 -> 0x30 (c)

(a) page for blk 0x20 is cached in META_MAPPING and page for blk 0x10
    is invalidated from META_MAPPING.
(b) write new data to blk 0x200 using IPU or DIO, but outdated data
    still remains in META_MAPPING.
(c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page in
    META_MAPPING. In conclusion, the newly written data in (b) is lost.

To address this issue, invalidating pages in META_MAPPING before IPU or
DIO write.

Signed-off-by: Hyeong-Jun Kim <hj514.kim@samsung.com>
---
 fs/f2fs/data.c    | 2 ++
 fs/f2fs/segment.c | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 74e1a350c1d8..9f754aaef558 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 		 */
 		f2fs_wait_on_block_writeback_range(inode,
 						map->m_pblk, map->m_len);
+		invalidate_mapping_pages(META_MAPPING(sbi),
+						map->m_pblk, map->m_pblk);
 
 		if (map->m_multidev_dio) {
 			block_t blk_addr = map->m_pblk;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 526423fe84ce..f57c55190f9e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct f2fs_io_info *fio)
 		goto drop_bio;
 	}
 
+	invalidate_mapping_pages(META_MAPPING(fio->sbi),
+				fio->new_blkaddr, fio->new_blkaddr);
+
 	stat_inc_inplace_blocks(fio->sbi);
 
 	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 << F2FS_IPU_NOCACHE)))
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 14+ messages in thread
* [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
@ 2021-11-01  5:42   ` Hyeong-Jun Kim
  0 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  5:42 UTC (permalink / raw)
  To: Jaegeuk Kim, Chao Yu; +Cc: linux-kernel, linux-f2fs-devel

Encrypted pages during GC are read and cached in META_MAPPING.
However, due to cached pages in META_MAPPING, there is an issue where
newly written pages are lost by IPU or DIO writes.

Thread A                              Thread B
- f2fs_gc(): blk 0x10 -> 0x20 (a)
                                      - IPU or DIO write on blk 0x20 (b)
- f2fs_gc(): blk 0x20 -> 0x30 (c)

(a) page for blk 0x20 is cached in META_MAPPING and page for blk 0x10
    is invalidated from META_MAPPING.
(b) write new data to blk 0x200 using IPU or DIO, but outdated data
    still remains in META_MAPPING.
(c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page in
    META_MAPPING. In conclusion, the newly written data in (b) is lost.

To address this issue, invalidating pages in META_MAPPING before IPU or
DIO write.

Signed-off-by: Hyeong-Jun Kim <hj514.kim@samsung.com>
---
 fs/f2fs/data.c    | 2 ++
 fs/f2fs/segment.c | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 74e1a350c1d8..9f754aaef558 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 		 */
 		f2fs_wait_on_block_writeback_range(inode,
 						map->m_pblk, map->m_len);
+		invalidate_mapping_pages(META_MAPPING(sbi),
+						map->m_pblk, map->m_pblk);
 
 		if (map->m_multidev_dio) {
 			block_t blk_addr = map->m_pblk;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 526423fe84ce..f57c55190f9e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct f2fs_io_info *fio)
 		goto drop_bio;
 	}
 
+	invalidate_mapping_pages(META_MAPPING(fio->sbi),
+				fio->new_blkaddr, fio->new_blkaddr);
+
 	stat_inc_inplace_blocks(fio->sbi);
 
 	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 << F2FS_IPU_NOCACHE)))
-- 
2.25.1



_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

^ permalink raw reply related	[flat|nested] 14+ messages in thread
* Re: [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
  2021-11-01  5:42   ` [f2fs-dev] " Hyeong-Jun Kim
@ 2021-11-01  6:28     ` Chao Yu
  -1 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2021-11-01  6:28 UTC (permalink / raw)
  To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel

On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> Encrypted pages during GC are read and cached in META_MAPPING.
> However, due to cached pages in META_MAPPING, there is an issue where
> newly written pages are lost by IPU or DIO writes.
> 
> Thread A                              Thread B
> - f2fs_gc(): blk 0x10 -> 0x20 (a)
>                                        - IPU or DIO write on blk 0x20 (b)
> - f2fs_gc(): blk 0x20 -> 0x30 (c)
> 
> (a) page for blk 0x20 is cached in META_MAPPING and page for blk 0x10
>      is invalidated from META_MAPPING.
> (b) write new data to blk 0x200 using IPU or DIO, but outdated data
>      still remains in META_MAPPING.
> (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page in
>      META_MAPPING. In conclusion, the newly written data in (b) is lost.

In c), f2fs_gc() will readahead encrypted block from disk via ra_data_block() anyway,
not matter cached encrypted page of meta inode is uptodate or not, so it's safe, right?

Am I missing anything?

Thanks,

> 
> To address this issue, invalidating pages in META_MAPPING before IPU or
> DIO write.
> 
> Signed-off-by: Hyeong-Jun Kim <hj514.kim@samsung.com>
> ---
>   fs/f2fs/data.c    | 2 ++
>   fs/f2fs/segment.c | 3 +++
>   2 files changed, 5 insertions(+)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 74e1a350c1d8..9f754aaef558 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>   		 */
>   		f2fs_wait_on_block_writeback_range(inode,
>   						map->m_pblk, map->m_len);
> +		invalidate_mapping_pages(META_MAPPING(sbi),
> +						map->m_pblk, map->m_pblk);
>   
>   		if (map->m_multidev_dio) {
>   			block_t blk_addr = map->m_pblk;
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 526423fe84ce..f57c55190f9e 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct f2fs_io_info *fio)
>   		goto drop_bio;
>   	}
>   
> +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> +				fio->new_blkaddr, fio->new_blkaddr);
> +
>   	stat_inc_inplace_blocks(fio->sbi);
>   
>   	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 << F2FS_IPU_NOCACHE)))
> 

^ permalink raw reply	[flat|nested] 14+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
@ 2021-11-01  6:28     ` Chao Yu
  0 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2021-11-01  6:28 UTC (permalink / raw)
  To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel

On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> Encrypted pages during GC are read and cached in META_MAPPING.
> However, due to cached pages in META_MAPPING, there is an issue where
> newly written pages are lost by IPU or DIO writes.
> 
> Thread A                              Thread B
> - f2fs_gc(): blk 0x10 -> 0x20 (a)
>                                        - IPU or DIO write on blk 0x20 (b)
> - f2fs_gc(): blk 0x20 -> 0x30 (c)
> 
> (a) page for blk 0x20 is cached in META_MAPPING and page for blk 0x10
>      is invalidated from META_MAPPING.
> (b) write new data to blk 0x200 using IPU or DIO, but outdated data
>      still remains in META_MAPPING.
> (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page in
>      META_MAPPING. In conclusion, the newly written data in (b) is lost.

In c), f2fs_gc() will readahead encrypted block from disk via ra_data_block() anyway,
not matter cached encrypted page of meta inode is uptodate or not, so it's safe, right?

Am I missing anything?

Thanks,

> 
> To address this issue, invalidating pages in META_MAPPING before IPU or
> DIO write.
> 
> Signed-off-by: Hyeong-Jun Kim <hj514.kim@samsung.com>
> ---
>   fs/f2fs/data.c    | 2 ++
>   fs/f2fs/segment.c | 3 +++
>   2 files changed, 5 insertions(+)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 74e1a350c1d8..9f754aaef558 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>   		 */
>   		f2fs_wait_on_block_writeback_range(inode,
>   						map->m_pblk, map->m_len);
> +		invalidate_mapping_pages(META_MAPPING(sbi),
> +						map->m_pblk, map->m_pblk);
>   
>   		if (map->m_multidev_dio) {
>   			block_t blk_addr = map->m_pblk;
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 526423fe84ce..f57c55190f9e 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct f2fs_io_info *fio)
>   		goto drop_bio;
>   	}
>   
> +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> +				fio->new_blkaddr, fio->new_blkaddr);
> +
>   	stat_inc_inplace_blocks(fio->sbi);
>   
>   	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 << F2FS_IPU_NOCACHE)))
> 


_______________________________________________
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] 14+ messages in thread
* Re: [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
  2021-11-01  6:28     ` [f2fs-dev] " Chao Yu
@ 2021-11-01  7:09       ` Hyeong-Jun Kim
  -1 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  7:09 UTC (permalink / raw)
  To: Chao Yu, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel

On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
> On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> > Encrypted pages during GC are read and cached in META_MAPPING.
> > However, due to cached pages in META_MAPPING, there is an issue
> > where
> > newly written pages are lost by IPU or DIO writes.
> > 
> > Thread A                              Thread B
> > - f2fs_gc(): blk 0x10 -> 0x20 (a)
> >                                        - IPU or DIO write on blk
> > 0x20 (b)
> > - f2fs_gc(): blk 0x20 -> 0x30 (c)
> > 
> > (a) page for blk 0x20 is cached in META_MAPPING and page for blk
> > 0x10
> >      is invalidated from META_MAPPING.
> > (b) write new data to blk 0x200 using IPU or DIO, but outdated data
> >      still remains in META_MAPPING.
> > (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page
> > in
> >      META_MAPPING. In conclusion, the newly written data in (b) is
> > lost.
> 
> In c), f2fs_gc() will readahead encrypted block from disk via
> ra_data_block() anyway,
> not matter cached encrypted page of meta inode is uptodate or not, so
> it's safe, right?
Right, 
However, if DIO write is performed between phase 3 and phase 4 of
f2fs_gc(),
the cached page of meta_mapping will be out-dated, though it read data
from 
disk via ra_data_block() in phase 3.

What do you think?

Thanks,
> 
> Am I missing anything?
> 
> Thanks,
> 
> > To address this issue, invalidating pages in META_MAPPING before
> > IPU or
> > DIO write.
> > 
> > Signed-off-by: Hyeong-Jun Kim <
> > hj514.kim@samsung.com
> > >
> > ---
> >   fs/f2fs/data.c    | 2 ++
> >   fs/f2fs/segment.c | 3 +++
> >   2 files changed, 5 insertions(+)
> > 
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 74e1a350c1d8..9f754aaef558 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
> > struct f2fs_map_blocks *map,
> >   		 */
> >   		f2fs_wait_on_block_writeback_range(inode,
> >   						map->m_pblk, map-
> > >m_len);
> > +		invalidate_mapping_pages(META_MAPPING(sbi),
> > +						map->m_pblk, map-
> > >m_pblk);
> >   
> >   		if (map->m_multidev_dio) {
> >   			block_t blk_addr = map->m_pblk;
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 526423fe84ce..f57c55190f9e 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
> > f2fs_io_info *fio)
> >   		goto drop_bio;
> >   	}
> >   
> > +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> > +				fio->new_blkaddr, fio->new_blkaddr);
> > +
> >   	stat_inc_inplace_blocks(fio->sbi);
> >   
> >   	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
> > F2FS_IPU_NOCACHE)))
> > 
> 
> 


^ permalink raw reply	[flat|nested] 14+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
@ 2021-11-01  7:09       ` Hyeong-Jun Kim
  0 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  7:09 UTC (permalink / raw)
  To: Chao Yu, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel

On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
> On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> > Encrypted pages during GC are read and cached in META_MAPPING.
> > However, due to cached pages in META_MAPPING, there is an issue
> > where
> > newly written pages are lost by IPU or DIO writes.
> > 
> > Thread A                              Thread B
> > - f2fs_gc(): blk 0x10 -> 0x20 (a)
> >                                        - IPU or DIO write on blk
> > 0x20 (b)
> > - f2fs_gc(): blk 0x20 -> 0x30 (c)
> > 
> > (a) page for blk 0x20 is cached in META_MAPPING and page for blk
> > 0x10
> >      is invalidated from META_MAPPING.
> > (b) write new data to blk 0x200 using IPU or DIO, but outdated data
> >      still remains in META_MAPPING.
> > (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page
> > in
> >      META_MAPPING. In conclusion, the newly written data in (b) is
> > lost.
> 
> In c), f2fs_gc() will readahead encrypted block from disk via
> ra_data_block() anyway,
> not matter cached encrypted page of meta inode is uptodate or not, so
> it's safe, right?
Right, 
However, if DIO write is performed between phase 3 and phase 4 of
f2fs_gc(),
the cached page of meta_mapping will be out-dated, though it read data
from 
disk via ra_data_block() in phase 3.

What do you think?

Thanks,
> 
> Am I missing anything?
> 
> Thanks,
> 
> > To address this issue, invalidating pages in META_MAPPING before
> > IPU or
> > DIO write.
> > 
> > Signed-off-by: Hyeong-Jun Kim <
> > hj514.kim@samsung.com
> > >
> > ---
> >   fs/f2fs/data.c    | 2 ++
> >   fs/f2fs/segment.c | 3 +++
> >   2 files changed, 5 insertions(+)
> > 
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 74e1a350c1d8..9f754aaef558 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
> > struct f2fs_map_blocks *map,
> >   		 */
> >   		f2fs_wait_on_block_writeback_range(inode,
> >   						map->m_pblk, map-
> > >m_len);
> > +		invalidate_mapping_pages(META_MAPPING(sbi),
> > +						map->m_pblk, map-
> > >m_pblk);
> >   
> >   		if (map->m_multidev_dio) {
> >   			block_t blk_addr = map->m_pblk;
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 526423fe84ce..f57c55190f9e 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
> > f2fs_io_info *fio)
> >   		goto drop_bio;
> >   	}
> >   
> > +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> > +				fio->new_blkaddr, fio->new_blkaddr);
> > +
> >   	stat_inc_inplace_blocks(fio->sbi);
> >   
> >   	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
> > F2FS_IPU_NOCACHE)))
> > 
> 
> 



_______________________________________________
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] 14+ messages in thread
* Re: [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
  2021-11-01  7:09       ` [f2fs-dev] " Hyeong-Jun Kim
@ 2021-11-01  7:12         ` Chao Yu
  -1 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2021-11-01  7:12 UTC (permalink / raw)
  To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel

On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
> On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
>> On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
>>> Encrypted pages during GC are read and cached in META_MAPPING.
>>> However, due to cached pages in META_MAPPING, there is an issue
>>> where
>>> newly written pages are lost by IPU or DIO writes.
>>>
>>> Thread A                              Thread B
>>> - f2fs_gc(): blk 0x10 -> 0x20 (a)
>>>                                         - IPU or DIO write on blk
>>> 0x20 (b)
>>> - f2fs_gc(): blk 0x20 -> 0x30 (c)
>>>
>>> (a) page for blk 0x20 is cached in META_MAPPING and page for blk
>>> 0x10
>>>       is invalidated from META_MAPPING.
>>> (b) write new data to blk 0x200 using IPU or DIO, but outdated data
>>>       still remains in META_MAPPING.
>>> (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page
>>> in
>>>       META_MAPPING. In conclusion, the newly written data in (b) is
>>> lost.
>>
>> In c), f2fs_gc() will readahead encrypted block from disk via
>> ra_data_block() anyway,
>> not matter cached encrypted page of meta inode is uptodate or not, so
>> it's safe, right?
> Right,
> However, if DIO write is performed between phase 3 and phase 4 of
> f2fs_gc(),
> the cached page of meta_mapping will be out-dated, though it read data
> from
> disk via ra_data_block() in phase 3.
> 
> What do you think?

Due to i_gc_rwsem lock coverage, the race condition should not happen right now?

Thanks,

> 
> Thanks,
>>
>> Am I missing anything?
>>
>> Thanks,
>>
>>> To address this issue, invalidating pages in META_MAPPING before
>>> IPU or
>>> DIO write.
>>>
>>> Signed-off-by: Hyeong-Jun Kim <
>>> hj514.kim@samsung.com
>>>>
>>> ---
>>>    fs/f2fs/data.c    | 2 ++
>>>    fs/f2fs/segment.c | 3 +++
>>>    2 files changed, 5 insertions(+)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 74e1a350c1d8..9f754aaef558 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
>>> struct f2fs_map_blocks *map,
>>>    		 */
>>>    		f2fs_wait_on_block_writeback_range(inode,
>>>    						map->m_pblk, map-
>>>> m_len);
>>> +		invalidate_mapping_pages(META_MAPPING(sbi),
>>> +						map->m_pblk, map-
>>>> m_pblk);
>>>    
>>>    		if (map->m_multidev_dio) {
>>>    			block_t blk_addr = map->m_pblk;
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 526423fe84ce..f57c55190f9e 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
>>> f2fs_io_info *fio)
>>>    		goto drop_bio;
>>>    	}
>>>    
>>> +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
>>> +				fio->new_blkaddr, fio->new_blkaddr);
>>> +
>>>    	stat_inc_inplace_blocks(fio->sbi);
>>>    
>>>    	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
>>> F2FS_IPU_NOCACHE)))
>>>
>>
>>
> 

^ permalink raw reply	[flat|nested] 14+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
@ 2021-11-01  7:12         ` Chao Yu
  0 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2021-11-01  7:12 UTC (permalink / raw)
  To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel

On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
> On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
>> On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
>>> Encrypted pages during GC are read and cached in META_MAPPING.
>>> However, due to cached pages in META_MAPPING, there is an issue
>>> where
>>> newly written pages are lost by IPU or DIO writes.
>>>
>>> Thread A                              Thread B
>>> - f2fs_gc(): blk 0x10 -> 0x20 (a)
>>>                                         - IPU or DIO write on blk
>>> 0x20 (b)
>>> - f2fs_gc(): blk 0x20 -> 0x30 (c)
>>>
>>> (a) page for blk 0x20 is cached in META_MAPPING and page for blk
>>> 0x10
>>>       is invalidated from META_MAPPING.
>>> (b) write new data to blk 0x200 using IPU or DIO, but outdated data
>>>       still remains in META_MAPPING.
>>> (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page
>>> in
>>>       META_MAPPING. In conclusion, the newly written data in (b) is
>>> lost.
>>
>> In c), f2fs_gc() will readahead encrypted block from disk via
>> ra_data_block() anyway,
>> not matter cached encrypted page of meta inode is uptodate or not, so
>> it's safe, right?
> Right,
> However, if DIO write is performed between phase 3 and phase 4 of
> f2fs_gc(),
> the cached page of meta_mapping will be out-dated, though it read data
> from
> disk via ra_data_block() in phase 3.
> 
> What do you think?

Due to i_gc_rwsem lock coverage, the race condition should not happen right now?

Thanks,

> 
> Thanks,
>>
>> Am I missing anything?
>>
>> Thanks,
>>
>>> To address this issue, invalidating pages in META_MAPPING before
>>> IPU or
>>> DIO write.
>>>
>>> Signed-off-by: Hyeong-Jun Kim <
>>> hj514.kim@samsung.com
>>>>
>>> ---
>>>    fs/f2fs/data.c    | 2 ++
>>>    fs/f2fs/segment.c | 3 +++
>>>    2 files changed, 5 insertions(+)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 74e1a350c1d8..9f754aaef558 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
>>> struct f2fs_map_blocks *map,
>>>    		 */
>>>    		f2fs_wait_on_block_writeback_range(inode,
>>>    						map->m_pblk, map-
>>>> m_len);
>>> +		invalidate_mapping_pages(META_MAPPING(sbi),
>>> +						map->m_pblk, map-
>>>> m_pblk);
>>>    
>>>    		if (map->m_multidev_dio) {
>>>    			block_t blk_addr = map->m_pblk;
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 526423fe84ce..f57c55190f9e 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
>>> f2fs_io_info *fio)
>>>    		goto drop_bio;
>>>    	}
>>>    
>>> +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
>>> +				fio->new_blkaddr, fio->new_blkaddr);
>>> +
>>>    	stat_inc_inplace_blocks(fio->sbi);
>>>    
>>>    	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
>>> F2FS_IPU_NOCACHE)))
>>>
>>
>>
> 


_______________________________________________
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] 14+ messages in thread
* Re: [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
  2021-11-01  7:12         ` [f2fs-dev] " Chao Yu
@ 2021-11-01  7:23           ` Hyeong-Jun Kim
  -1 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  7:23 UTC (permalink / raw)
  To: Chao Yu, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel

On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote:
> On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
> > On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
> > > On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> > > > Encrypted pages during GC are read and cached in META_MAPPING.
> > > > However, due to cached pages in META_MAPPING, there is an issue
> > > > where
> > > > newly written pages are lost by IPU or DIO writes.
> > > > 
> > > > Thread A                              Thread B
> > > > - f2fs_gc(): blk 0x10 -> 0x20 (a)
> > > >                                         - IPU or DIO write on
> > > > blk
> > > > 0x20 (b)
> > > > - f2fs_gc(): blk 0x20 -> 0x30 (c)
> > > > 
> > > > (a) page for blk 0x20 is cached in META_MAPPING and page for
> > > > blk
> > > > 0x10
> > > >       is invalidated from META_MAPPING.
> > > > (b) write new data to blk 0x200 using IPU or DIO, but outdated
> > > > data
> > > >       still remains in META_MAPPING.
> > > > (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached
> > > > page
> > > > in
> > > >       META_MAPPING. In conclusion, the newly written data in
> > > > (b) is
> > > > lost.
> > > 
> > > In c), f2fs_gc() will readahead encrypted block from disk via
> > > ra_data_block() anyway,
> > > not matter cached encrypted page of meta inode is uptodate or
> > > not, so
> > > it's safe, right?
> > 
> > Right,
> > However, if DIO write is performed between phase 3 and phase 4 of
> > f2fs_gc(),
> > the cached page of meta_mapping will be out-dated, though it read
> > data
> > from
> > disk via ra_data_block() in phase 3.
> > 
> > What do you think?
> 
> Due to i_gc_rwsem lock coverage, the race condition should not happen
> right now?
> 
- Thread A                                       - Thread B
/* phase 3 */
down_write(i_gc_rwsem)
ra_data_block()
up_write(i_gc_rwsem)
                                                       
 f2fs_direct_IO() : 
                                                       
 down_read(i_gc_rwsem)
                                                       
 __blockdev_direct_IO()
                                                           ...
                                                         
 get_ddata_block_dio_write()
                                                           ...
                                                         
 f2fs_dio_submit_bio()
                                                       
 up_read(i_gc_rwsem)
/* phase 4 */
down_write(i_gc_rwsem)
move_data_block()
up_write(i_gc_rwsem)

It looks, i_gc_rwsem could not protect page update between phase 3 and
4.

Am I missing anything?

Thanks

> Thanks,
> 
> > Thanks,
> > > Am I missing anything?
> > > 
> > > Thanks,
> > > 
> > > > To address this issue, invalidating pages in META_MAPPING
> > > > before
> > > > IPU or
> > > > DIO write.
> > > > 
> > > > Signed-off-by: Hyeong-Jun Kim <
> > > > hj514.kim@samsung.com
> > > > 
> > > > 
> > > > ---
> > > >    fs/f2fs/data.c    | 2 ++
> > > >    fs/f2fs/segment.c | 3 +++
> > > >    2 files changed, 5 insertions(+)
> > > > 
> > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > > index 74e1a350c1d8..9f754aaef558 100644
> > > > --- a/fs/f2fs/data.c
> > > > +++ b/fs/f2fs/data.c
> > > > @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
> > > > struct f2fs_map_blocks *map,
> > > >    		 */
> > > >    		f2fs_wait_on_block_writeback_range(inode,
> > > >    						map->m_pblk,
> > > > map-
> > > > > m_len);
> > > > 
> > > > +		invalidate_mapping_pages(META_MAPPING(sbi),
> > > > +						map->m_pblk,
> > > > map-
> > > > > m_pblk);
> > > > 
> > > >    
> > > >    		if (map->m_multidev_dio) {
> > > >    			block_t blk_addr = map->m_pblk;
> > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > index 526423fe84ce..f57c55190f9e 100644
> > > > --- a/fs/f2fs/segment.c
> > > > +++ b/fs/f2fs/segment.c
> > > > @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
> > > > f2fs_io_info *fio)
> > > >    		goto drop_bio;
> > > >    	}
> > > >    
> > > > +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> > > > +				fio->new_blkaddr, fio-
> > > > >new_blkaddr);
> > > > +
> > > >    	stat_inc_inplace_blocks(fio->sbi);
> > > >    
> > > >    	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
> > > > F2FS_IPU_NOCACHE)))
> > > > 
> > > 
> > > 
> 
> 


^ permalink raw reply	[flat|nested] 14+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
@ 2021-11-01  7:23           ` Hyeong-Jun Kim
  0 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  7:23 UTC (permalink / raw)
  To: Chao Yu, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel

On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote:
> On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
> > On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
> > > On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> > > > Encrypted pages during GC are read and cached in META_MAPPING.
> > > > However, due to cached pages in META_MAPPING, there is an issue
> > > > where
> > > > newly written pages are lost by IPU or DIO writes.
> > > > 
> > > > Thread A                              Thread B
> > > > - f2fs_gc(): blk 0x10 -> 0x20 (a)
> > > >                                         - IPU or DIO write on
> > > > blk
> > > > 0x20 (b)
> > > > - f2fs_gc(): blk 0x20 -> 0x30 (c)
> > > > 
> > > > (a) page for blk 0x20 is cached in META_MAPPING and page for
> > > > blk
> > > > 0x10
> > > >       is invalidated from META_MAPPING.
> > > > (b) write new data to blk 0x200 using IPU or DIO, but outdated
> > > > data
> > > >       still remains in META_MAPPING.
> > > > (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached
> > > > page
> > > > in
> > > >       META_MAPPING. In conclusion, the newly written data in
> > > > (b) is
> > > > lost.
> > > 
> > > In c), f2fs_gc() will readahead encrypted block from disk via
> > > ra_data_block() anyway,
> > > not matter cached encrypted page of meta inode is uptodate or
> > > not, so
> > > it's safe, right?
> > 
> > Right,
> > However, if DIO write is performed between phase 3 and phase 4 of
> > f2fs_gc(),
> > the cached page of meta_mapping will be out-dated, though it read
> > data
> > from
> > disk via ra_data_block() in phase 3.
> > 
> > What do you think?
> 
> Due to i_gc_rwsem lock coverage, the race condition should not happen
> right now?
> 
- Thread A                                       - Thread B
/* phase 3 */
down_write(i_gc_rwsem)
ra_data_block()
up_write(i_gc_rwsem)
                                                       
 f2fs_direct_IO() : 
                                                       
 down_read(i_gc_rwsem)
                                                       
 __blockdev_direct_IO()
                                                           ...
                                                         
 get_ddata_block_dio_write()
                                                           ...
                                                         
 f2fs_dio_submit_bio()
                                                       
 up_read(i_gc_rwsem)
/* phase 4 */
down_write(i_gc_rwsem)
move_data_block()
up_write(i_gc_rwsem)

It looks, i_gc_rwsem could not protect page update between phase 3 and
4.

Am I missing anything?

Thanks

> Thanks,
> 
> > Thanks,
> > > Am I missing anything?
> > > 
> > > Thanks,
> > > 
> > > > To address this issue, invalidating pages in META_MAPPING
> > > > before
> > > > IPU or
> > > > DIO write.
> > > > 
> > > > Signed-off-by: Hyeong-Jun Kim <
> > > > hj514.kim@samsung.com
> > > > 
> > > > 
> > > > ---
> > > >    fs/f2fs/data.c    | 2 ++
> > > >    fs/f2fs/segment.c | 3 +++
> > > >    2 files changed, 5 insertions(+)
> > > > 
> > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > > index 74e1a350c1d8..9f754aaef558 100644
> > > > --- a/fs/f2fs/data.c
> > > > +++ b/fs/f2fs/data.c
> > > > @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
> > > > struct f2fs_map_blocks *map,
> > > >    		 */
> > > >    		f2fs_wait_on_block_writeback_range(inode,
> > > >    						map->m_pblk,
> > > > map-
> > > > > m_len);
> > > > 
> > > > +		invalidate_mapping_pages(META_MAPPING(sbi),
> > > > +						map->m_pblk,
> > > > map-
> > > > > m_pblk);
> > > > 
> > > >    
> > > >    		if (map->m_multidev_dio) {
> > > >    			block_t blk_addr = map->m_pblk;
> > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > index 526423fe84ce..f57c55190f9e 100644
> > > > --- a/fs/f2fs/segment.c
> > > > +++ b/fs/f2fs/segment.c
> > > > @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
> > > > f2fs_io_info *fio)
> > > >    		goto drop_bio;
> > > >    	}
> > > >    
> > > > +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> > > > +				fio->new_blkaddr, fio-
> > > > >new_blkaddr);
> > > > +
> > > >    	stat_inc_inplace_blocks(fio->sbi);
> > > >    
> > > >    	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
> > > > F2FS_IPU_NOCACHE)))
> > > > 
> > > 
> > > 
> 
> 



_______________________________________________
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] 14+ messages in thread
* Re: [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
  2021-11-01  7:23           ` [f2fs-dev] " Hyeong-Jun Kim
@ 2021-11-01  8:11             ` Chao Yu
  -1 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2021-11-01  8:11 UTC (permalink / raw)
  To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel

On 2021/11/1 15:23, Hyeong-Jun Kim wrote:
> On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote:
>> On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
>>> On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
>>>> On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
>>>>> Encrypted pages during GC are read and cached in META_MAPPING.
>>>>> However, due to cached pages in META_MAPPING, there is an issue
>>>>> where
>>>>> newly written pages are lost by IPU or DIO writes.
>>>>>
>>>>> Thread A                              Thread B
>>>>> - f2fs_gc(): blk 0x10 -> 0x20 (a)
>>>>>                                          - IPU or DIO write on
>>>>> blk
>>>>> 0x20 (b)
>>>>> - f2fs_gc(): blk 0x20 -> 0x30 (c)
>>>>>
>>>>> (a) page for blk 0x20 is cached in META_MAPPING and page for
>>>>> blk
>>>>> 0x10
>>>>>        is invalidated from META_MAPPING.
>>>>> (b) write new data to blk 0x200 using IPU or DIO, but outdated
>>>>> data
>>>>>        still remains in META_MAPPING.
>>>>> (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached
>>>>> page
>>>>> in
>>>>>        META_MAPPING. In conclusion, the newly written data in
>>>>> (b) is
>>>>> lost.
>>>>
>>>> In c), f2fs_gc() will readahead encrypted block from disk via
>>>> ra_data_block() anyway,
>>>> not matter cached encrypted page of meta inode is uptodate or
>>>> not, so
>>>> it's safe, right?
>>>
>>> Right,
>>> However, if DIO write is performed between phase 3 and phase 4 of
>>> f2fs_gc(),
>>> the cached page of meta_mapping will be out-dated, though it read
>>> data
>>> from
>>> disk via ra_data_block() in phase 3.
>>>
>>> What do you think?
>>
>> Due to i_gc_rwsem lock coverage, the race condition should not happen
>> right now?
>>
> - Thread A                                       - Thread B
> /* phase 3 */
> down_write(i_gc_rwsem)
> ra_data_block()
> up_write(i_gc_rwsem)
>                                                         
>   f2fs_direct_IO() :
>                                                         
>   down_read(i_gc_rwsem)
>                                                         
>   __blockdev_direct_IO()
>                                                             ...
>                                                           
>   get_ddata_block_dio_write()
>                                                             ...
>                                                           
>   f2fs_dio_submit_bio()
>                                                         
>   up_read(i_gc_rwsem)
> /* phase 4 */
> down_write(i_gc_rwsem)
> move_data_block()
> up_write(i_gc_rwsem)
> 
> It looks, i_gc_rwsem could not protect page update between phase 3 and
> 4.
> 
> Am I missing anything?

It looks you're right, there is a hole in between readahead and movepage functions...

Could you please update the race condition description? and add a tag as below to fix
stable kernel as well:

Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")

Thanks,

> 
> Thanks
> 
>> Thanks,
>>
>>> Thanks,
>>>> Am I missing anything?
>>>>
>>>> Thanks,
>>>>
>>>>> To address this issue, invalidating pages in META_MAPPING
>>>>> before
>>>>> IPU or
>>>>> DIO write.
>>>>>
>>>>> Signed-off-by: Hyeong-Jun Kim <
>>>>> hj514.kim@samsung.com
>>>>>
>>>>>
>>>>> ---
>>>>>     fs/f2fs/data.c    | 2 ++
>>>>>     fs/f2fs/segment.c | 3 +++
>>>>>     2 files changed, 5 insertions(+)
>>>>>
>>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>>> index 74e1a350c1d8..9f754aaef558 100644
>>>>> --- a/fs/f2fs/data.c
>>>>> +++ b/fs/f2fs/data.c
>>>>> @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
>>>>> struct f2fs_map_blocks *map,
>>>>>     		 */
>>>>>     		f2fs_wait_on_block_writeback_range(inode,
>>>>>     						map->m_pblk,
>>>>> map-
>>>>>> m_len);
>>>>>
>>>>> +		invalidate_mapping_pages(META_MAPPING(sbi),
>>>>> +						map->m_pblk,
>>>>> map-
>>>>>> m_pblk);
>>>>>
>>>>>     
>>>>>     		if (map->m_multidev_dio) {
>>>>>     			block_t blk_addr = map->m_pblk;
>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>>> index 526423fe84ce..f57c55190f9e 100644
>>>>> --- a/fs/f2fs/segment.c
>>>>> +++ b/fs/f2fs/segment.c
>>>>> @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
>>>>> f2fs_io_info *fio)
>>>>>     		goto drop_bio;
>>>>>     	}
>>>>>     
>>>>> +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
>>>>> +				fio->new_blkaddr, fio-
>>>>>> new_blkaddr);
>>>>> +
>>>>>     	stat_inc_inplace_blocks(fio->sbi);
>>>>>     
>>>>>     	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
>>>>> F2FS_IPU_NOCACHE)))
>>>>>
>>>>
>>>>
>>
>>
> 

^ permalink raw reply	[flat|nested] 14+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
@ 2021-11-01  8:11             ` Chao Yu
  0 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2021-11-01  8:11 UTC (permalink / raw)
  To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel

On 2021/11/1 15:23, Hyeong-Jun Kim wrote:
> On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote:
>> On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
>>> On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
>>>> On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
>>>>> Encrypted pages during GC are read and cached in META_MAPPING.
>>>>> However, due to cached pages in META_MAPPING, there is an issue
>>>>> where
>>>>> newly written pages are lost by IPU or DIO writes.
>>>>>
>>>>> Thread A                              Thread B
>>>>> - f2fs_gc(): blk 0x10 -> 0x20 (a)
>>>>>                                          - IPU or DIO write on
>>>>> blk
>>>>> 0x20 (b)
>>>>> - f2fs_gc(): blk 0x20 -> 0x30 (c)
>>>>>
>>>>> (a) page for blk 0x20 is cached in META_MAPPING and page for
>>>>> blk
>>>>> 0x10
>>>>>        is invalidated from META_MAPPING.
>>>>> (b) write new data to blk 0x200 using IPU or DIO, but outdated
>>>>> data
>>>>>        still remains in META_MAPPING.
>>>>> (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached
>>>>> page
>>>>> in
>>>>>        META_MAPPING. In conclusion, the newly written data in
>>>>> (b) is
>>>>> lost.
>>>>
>>>> In c), f2fs_gc() will readahead encrypted block from disk via
>>>> ra_data_block() anyway,
>>>> not matter cached encrypted page of meta inode is uptodate or
>>>> not, so
>>>> it's safe, right?
>>>
>>> Right,
>>> However, if DIO write is performed between phase 3 and phase 4 of
>>> f2fs_gc(),
>>> the cached page of meta_mapping will be out-dated, though it read
>>> data
>>> from
>>> disk via ra_data_block() in phase 3.
>>>
>>> What do you think?
>>
>> Due to i_gc_rwsem lock coverage, the race condition should not happen
>> right now?
>>
> - Thread A                                       - Thread B
> /* phase 3 */
> down_write(i_gc_rwsem)
> ra_data_block()
> up_write(i_gc_rwsem)
>                                                         
>   f2fs_direct_IO() :
>                                                         
>   down_read(i_gc_rwsem)
>                                                         
>   __blockdev_direct_IO()
>                                                             ...
>                                                           
>   get_ddata_block_dio_write()
>                                                             ...
>                                                           
>   f2fs_dio_submit_bio()
>                                                         
>   up_read(i_gc_rwsem)
> /* phase 4 */
> down_write(i_gc_rwsem)
> move_data_block()
> up_write(i_gc_rwsem)
> 
> It looks, i_gc_rwsem could not protect page update between phase 3 and
> 4.
> 
> Am I missing anything?

It looks you're right, there is a hole in between readahead and movepage functions...

Could you please update the race condition description? and add a tag as below to fix
stable kernel as well:

Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")

Thanks,

> 
> Thanks
> 
>> Thanks,
>>
>>> Thanks,
>>>> Am I missing anything?
>>>>
>>>> Thanks,
>>>>
>>>>> To address this issue, invalidating pages in META_MAPPING
>>>>> before
>>>>> IPU or
>>>>> DIO write.
>>>>>
>>>>> Signed-off-by: Hyeong-Jun Kim <
>>>>> hj514.kim@samsung.com
>>>>>
>>>>>
>>>>> ---
>>>>>     fs/f2fs/data.c    | 2 ++
>>>>>     fs/f2fs/segment.c | 3 +++
>>>>>     2 files changed, 5 insertions(+)
>>>>>
>>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>>> index 74e1a350c1d8..9f754aaef558 100644
>>>>> --- a/fs/f2fs/data.c
>>>>> +++ b/fs/f2fs/data.c
>>>>> @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
>>>>> struct f2fs_map_blocks *map,
>>>>>     		 */
>>>>>     		f2fs_wait_on_block_writeback_range(inode,
>>>>>     						map->m_pblk,
>>>>> map-
>>>>>> m_len);
>>>>>
>>>>> +		invalidate_mapping_pages(META_MAPPING(sbi),
>>>>> +						map->m_pblk,
>>>>> map-
>>>>>> m_pblk);
>>>>>
>>>>>     
>>>>>     		if (map->m_multidev_dio) {
>>>>>     			block_t blk_addr = map->m_pblk;
>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>>> index 526423fe84ce..f57c55190f9e 100644
>>>>> --- a/fs/f2fs/segment.c
>>>>> +++ b/fs/f2fs/segment.c
>>>>> @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
>>>>> f2fs_io_info *fio)
>>>>>     		goto drop_bio;
>>>>>     	}
>>>>>     
>>>>> +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
>>>>> +				fio->new_blkaddr, fio-
>>>>>> new_blkaddr);
>>>>> +
>>>>>     	stat_inc_inplace_blocks(fio->sbi);
>>>>>     
>>>>>     	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
>>>>> F2FS_IPU_NOCACHE)))
>>>>>
>>>>
>>>>
>>
>>
> 


_______________________________________________
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] 14+ messages in thread
* Re: [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
  2021-11-01  8:11             ` [f2fs-dev] " Chao Yu
@ 2021-11-01  8:38               ` Hyeong-Jun Kim
  -1 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  8:38 UTC (permalink / raw)
  To: Chao Yu, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel

On Mon, 2021-11-01 at 16:11 +0800, Chao Yu wrote:
> On 2021/11/1 15:23, Hyeong-Jun Kim wrote:
> > On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote:
> > > On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
> > > > On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
> > > > > On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> > > > > > Encrypted pages during GC are read and cached in
> > > > > > META_MAPPING.
> > > > > > However, due to cached pages in META_MAPPING, there is an
> > > > > > issue
> > > > > > where
> > > > > > newly written pages are lost by IPU or DIO writes.
> > > > > > 
> > > > > > Thread A                              Thread B
> > > > > > - f2fs_gc(): blk 0x10 -> 0x20 (a)
> > > > > >                                          - IPU or DIO write
> > > > > > on
> > > > > > blk
> > > > > > 0x20 (b)
> > > > > > - f2fs_gc(): blk 0x20 -> 0x30 (c)
> > > > > > 
> > > > > > (a) page for blk 0x20 is cached in META_MAPPING and page
> > > > > > for
> > > > > > blk
> > > > > > 0x10
> > > > > >        is invalidated from META_MAPPING.
> > > > > > (b) write new data to blk 0x200 using IPU or DIO, but
> > > > > > outdated
> > > > > > data
> > > > > >        still remains in META_MAPPING.
> > > > > > (c) f2fs_gc() try to move blk from 0x20 to 0x30 using
> > > > > > cached
> > > > > > page
> > > > > > in
> > > > > >        META_MAPPING. In conclusion, the newly written data
> > > > > > in
> > > > > > (b) is
> > > > > > lost.
> > > > > 
> > > > > In c), f2fs_gc() will readahead encrypted block from disk via
> > > > > ra_data_block() anyway,
> > > > > not matter cached encrypted page of meta inode is uptodate or
> > > > > not, so
> > > > > it's safe, right?
> > > > 
> > > > Right,
> > > > However, if DIO write is performed between phase 3 and phase 4
> > > > of
> > > > f2fs_gc(),
> > > > the cached page of meta_mapping will be out-dated, though it
> > > > read
> > > > data
> > > > from
> > > > disk via ra_data_block() in phase 3.
> > > > 
> > > > What do you think?
> > > 
> > > Due to i_gc_rwsem lock coverage, the race condition should not
> > > happen
> > > right now?
> > > 
> > 
> > - Thread A                                       - Thread B
> > /* phase 3 */
> > down_write(i_gc_rwsem)
> > ra_data_block()
> > up_write(i_gc_rwsem)
> >                                                         
> >   f2fs_direct_IO() :
> >                                                         
> >   down_read(i_gc_rwsem)
> >                                                         
> >   __blockdev_direct_IO()
> >                                                             ...
> >                                                           
> >   get_ddata_block_dio_write()
> >                                                             ...
> >                                                           
> >   f2fs_dio_submit_bio()
> >                                                         
> >   up_read(i_gc_rwsem)
> > /* phase 4 */
> > down_write(i_gc_rwsem)
> > move_data_block()
> > up_write(i_gc_rwsem)
> > 
> > It looks, i_gc_rwsem could not protect page update between phase 3
> > and
> > 4.
> > 
> > Am I missing anything?
> 
> It looks you're right, there is a hole in between readahead and
> movepage functions...
> 
> Could you please update the race condition description? and add a tag
> as below to fix
> stable kernel as well:
> 
> Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")
> 
> Thanks,
Thank for your comment.
I will send Patch v2 with new description.

Thanks,
> 
> > Thanks
> > 
> > > Thanks,
> > > 
> > > > Thanks,
> > > > > Am I missing anything?
> > > > > 
> > > > > Thanks,
> > > > > 
> > > > > > To address this issue, invalidating pages in META_MAPPING
> > > > > > before
> > > > > > IPU or
> > > > > > DIO write.
> > > > > > 
> > > > > > Signed-off-by: Hyeong-Jun Kim <
> > > > > > hj514.kim@samsung.com
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > > ---
> > > > > >     fs/f2fs/data.c    | 2 ++
> > > > > >     fs/f2fs/segment.c | 3 +++
> > > > > >     2 files changed, 5 insertions(+)
> > > > > > 
> > > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > > > > index 74e1a350c1d8..9f754aaef558 100644
> > > > > > --- a/fs/f2fs/data.c
> > > > > > +++ b/fs/f2fs/data.c
> > > > > > @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode
> > > > > > *inode,
> > > > > > struct f2fs_map_blocks *map,
> > > > > >     		 */
> > > > > >     		f2fs_wait_on_block_writeback_range(inod
> > > > > > e,
> > > > > >     						map-
> > > > > > >m_pblk,
> > > > > > map-
> > > > > > > m_len);
> > > > > > 
> > > > > > +		invalidate_mapping_pages(META_MAPPING(sbi),
> > > > > > +						map->m_pblk,
> > > > > > map-
> > > > > > > m_pblk);
> > > > > > 
> > > > > >     
> > > > > >     		if (map->m_multidev_dio) {
> > > > > >     			block_t blk_addr = map->m_pblk;
> > > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > > index 526423fe84ce..f57c55190f9e 100644
> > > > > > --- a/fs/f2fs/segment.c
> > > > > > +++ b/fs/f2fs/segment.c
> > > > > > @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
> > > > > > f2fs_io_info *fio)
> > > > > >     		goto drop_bio;
> > > > > >     	}
> > > > > >     
> > > > > > +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> > > > > > +				fio->new_blkaddr, fio-
> > > > > > > new_blkaddr);
> > > > > > 
> > > > > > +
> > > > > >     	stat_inc_inplace_blocks(fio->sbi);
> > > > > >     
> > > > > >     	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
> > > > > > F2FS_IPU_NOCACHE)))
> > > > > > 
> > > > > 
> > > > > 
> > > 
> > > 
> 
> 


^ permalink raw reply	[flat|nested] 14+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write
@ 2021-11-01  8:38               ` Hyeong-Jun Kim
  0 siblings, 0 replies; 14+ messages in thread
From: Hyeong-Jun Kim @ 2021-11-01  8:38 UTC (permalink / raw)
  To: Chao Yu, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel

On Mon, 2021-11-01 at 16:11 +0800, Chao Yu wrote:
> On 2021/11/1 15:23, Hyeong-Jun Kim wrote:
> > On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote:
> > > On 2021/11/1 15:09, Hyeong-Jun Kim wrote:
> > > > On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote:
> > > > > On 2021/11/1 13:42, Hyeong-Jun Kim wrote:
> > > > > > Encrypted pages during GC are read and cached in
> > > > > > META_MAPPING.
> > > > > > However, due to cached pages in META_MAPPING, there is an
> > > > > > issue
> > > > > > where
> > > > > > newly written pages are lost by IPU or DIO writes.
> > > > > > 
> > > > > > Thread A                              Thread B
> > > > > > - f2fs_gc(): blk 0x10 -> 0x20 (a)
> > > > > >                                          - IPU or DIO write
> > > > > > on
> > > > > > blk
> > > > > > 0x20 (b)
> > > > > > - f2fs_gc(): blk 0x20 -> 0x30 (c)
> > > > > > 
> > > > > > (a) page for blk 0x20 is cached in META_MAPPING and page
> > > > > > for
> > > > > > blk
> > > > > > 0x10
> > > > > >        is invalidated from META_MAPPING.
> > > > > > (b) write new data to blk 0x200 using IPU or DIO, but
> > > > > > outdated
> > > > > > data
> > > > > >        still remains in META_MAPPING.
> > > > > > (c) f2fs_gc() try to move blk from 0x20 to 0x30 using
> > > > > > cached
> > > > > > page
> > > > > > in
> > > > > >        META_MAPPING. In conclusion, the newly written data
> > > > > > in
> > > > > > (b) is
> > > > > > lost.
> > > > > 
> > > > > In c), f2fs_gc() will readahead encrypted block from disk via
> > > > > ra_data_block() anyway,
> > > > > not matter cached encrypted page of meta inode is uptodate or
> > > > > not, so
> > > > > it's safe, right?
> > > > 
> > > > Right,
> > > > However, if DIO write is performed between phase 3 and phase 4
> > > > of
> > > > f2fs_gc(),
> > > > the cached page of meta_mapping will be out-dated, though it
> > > > read
> > > > data
> > > > from
> > > > disk via ra_data_block() in phase 3.
> > > > 
> > > > What do you think?
> > > 
> > > Due to i_gc_rwsem lock coverage, the race condition should not
> > > happen
> > > right now?
> > > 
> > 
> > - Thread A                                       - Thread B
> > /* phase 3 */
> > down_write(i_gc_rwsem)
> > ra_data_block()
> > up_write(i_gc_rwsem)
> >                                                         
> >   f2fs_direct_IO() :
> >                                                         
> >   down_read(i_gc_rwsem)
> >                                                         
> >   __blockdev_direct_IO()
> >                                                             ...
> >                                                           
> >   get_ddata_block_dio_write()
> >                                                             ...
> >                                                           
> >   f2fs_dio_submit_bio()
> >                                                         
> >   up_read(i_gc_rwsem)
> > /* phase 4 */
> > down_write(i_gc_rwsem)
> > move_data_block()
> > up_write(i_gc_rwsem)
> > 
> > It looks, i_gc_rwsem could not protect page update between phase 3
> > and
> > 4.
> > 
> > Am I missing anything?
> 
> It looks you're right, there is a hole in between readahead and
> movepage functions...
> 
> Could you please update the race condition description? and add a tag
> as below to fix
> stable kernel as well:
> 
> Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")
> 
> Thanks,
Thank for your comment.
I will send Patch v2 with new description.

Thanks,
> 
> > Thanks
> > 
> > > Thanks,
> > > 
> > > > Thanks,
> > > > > Am I missing anything?
> > > > > 
> > > > > Thanks,
> > > > > 
> > > > > > To address this issue, invalidating pages in META_MAPPING
> > > > > > before
> > > > > > IPU or
> > > > > > DIO write.
> > > > > > 
> > > > > > Signed-off-by: Hyeong-Jun Kim <
> > > > > > hj514.kim@samsung.com
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > > ---
> > > > > >     fs/f2fs/data.c    | 2 ++
> > > > > >     fs/f2fs/segment.c | 3 +++
> > > > > >     2 files changed, 5 insertions(+)
> > > > > > 
> > > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > > > > index 74e1a350c1d8..9f754aaef558 100644
> > > > > > --- a/fs/f2fs/data.c
> > > > > > +++ b/fs/f2fs/data.c
> > > > > > @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode
> > > > > > *inode,
> > > > > > struct f2fs_map_blocks *map,
> > > > > >     		 */
> > > > > >     		f2fs_wait_on_block_writeback_range(inod
> > > > > > e,
> > > > > >     						map-
> > > > > > >m_pblk,
> > > > > > map-
> > > > > > > m_len);
> > > > > > 
> > > > > > +		invalidate_mapping_pages(META_MAPPING(sbi),
> > > > > > +						map->m_pblk,
> > > > > > map-
> > > > > > > m_pblk);
> > > > > > 
> > > > > >     
> > > > > >     		if (map->m_multidev_dio) {
> > > > > >     			block_t blk_addr = map->m_pblk;
> > > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > > > index 526423fe84ce..f57c55190f9e 100644
> > > > > > --- a/fs/f2fs/segment.c
> > > > > > +++ b/fs/f2fs/segment.c
> > > > > > @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
> > > > > > f2fs_io_info *fio)
> > > > > >     		goto drop_bio;
> > > > > >     	}
> > > > > >     
> > > > > > +	invalidate_mapping_pages(META_MAPPING(fio->sbi),
> > > > > > +				fio->new_blkaddr, fio-
> > > > > > > new_blkaddr);
> > > > > > 
> > > > > > +
> > > > > >     	stat_inc_inplace_blocks(fio->sbi);
> > > > > >     
> > > > > >     	if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
> > > > > > F2FS_IPU_NOCACHE)))
> > > > > > 
> > > > > 
> > > > > 
> > > 
> > > 
> 
> 



_______________________________________________
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https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

^ permalink raw reply	[flat|nested] 14+ messages in thread
end of thread, other threads:[~2021-11-01  8:39 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <CGME20211101054217epcas1p3c695f37ab925f47156bd45e3adb5ed94@epcas1p3.samsung.com>
2021-11-01  5:42 ` [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write Hyeong-Jun Kim
2021-11-01  5:42   ` [f2fs-dev] " Hyeong-Jun Kim
2021-11-01  6:28   ` Chao Yu
2021-11-01  6:28     ` [f2fs-dev] " Chao Yu
2021-11-01  7:09     ` Hyeong-Jun Kim
2021-11-01  7:09       ` [f2fs-dev] " Hyeong-Jun Kim
2021-11-01  7:12       ` Chao Yu
2021-11-01  7:12         ` [f2fs-dev] " Chao Yu
2021-11-01  7:23         ` Hyeong-Jun Kim
2021-11-01  7:23           ` [f2fs-dev] " Hyeong-Jun Kim
2021-11-01  8:11           ` Chao Yu
2021-11-01  8:11             ` [f2fs-dev] " Chao Yu
2021-11-01  8:38             ` Hyeong-Jun Kim
2021-11-01  8:38               ` [f2fs-dev] " Hyeong-Jun Kim

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