Re: [f2fs-dev] [PATCH 1/4] f2fs: fix blkofs_end correctly in f2fs_migrate_blocks()

[Chao Yu <chao@kernel.org>]

On 2024/3/1 1:41, Daeho Jeong wrote:
> On Thu, Feb 29, 2024 at 2:11 AM Chao Yu <chao@kernel.org> wrote:
>>
>> Jaegeuk, Daeho,
>>
>> Any comments on this serials?
>>
>> Thanks,
> 
> No functional difference here, since start_blk is always aligned with
> the section address.

You're right.

> However, this is more clear in itself.

Thanks for the review!

One more thing is, I found that fallocate() on pinned file will preallocate
aligned w/ section-size which is about several hundred megabyte for ZUFS case,
since commit e1175f022911 ("f2fs: fix to align to section for fallocate() on
pinned file").

It looks not make sense, especially for logcat case which actually want to
preallocate 2MB space, so, what about reverting commit e1175f022911 and
looking for other solution to avoid GCing on fragmented pinned file.

What do you think?

Thanks,

> 
> Reviewed-by: Daeho Jeong <daehojeong@google.com>
> 
> Thanks,
> 
>>
>> On 2024/2/26 9:32, Chao Yu wrote:
>>> In f2fs_migrate_blocks(), when traversing blocks in last section,
>>> blkofs_end should be (start_blk + blkcnt - 1) % blk_per_sec, fix it.
>>>
>>> Signed-off-by: Chao Yu <chao@kernel.org>
>>> ---
>>>    fs/f2fs/data.c | 5 +++--
>>>    1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index c21b92f18463..0c728e82d936 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -3841,13 +3841,14 @@ static int f2fs_migrate_blocks(struct inode *inode, block_t start_blk,
>>>        struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>        unsigned int blkofs;
>>>        unsigned int blk_per_sec = BLKS_PER_SEC(sbi);
>>> +     unsigned int end_blk = start_blk + blkcnt - 1;
>>>        unsigned int secidx = start_blk / blk_per_sec;
>>>        unsigned int end_sec;
>>>        int ret = 0;
>>>
>>>        if (!blkcnt)
>>>                return 0;
>>> -     end_sec = secidx + (blkcnt - 1) / blk_per_sec;
>>> +     end_sec = end_blk / blk_per_sec;
>>>
>>>        f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>>>        filemap_invalidate_lock(inode->i_mapping);
>>> @@ -3857,7 +3858,7 @@ static int f2fs_migrate_blocks(struct inode *inode, block_t start_blk,
>>>
>>>        for (; secidx <= end_sec; secidx++) {
>>>                unsigned int blkofs_end = secidx == end_sec ?
>>> -                     (blkcnt - 1) % blk_per_sec : blk_per_sec - 1;
>>> +                             end_blk % blk_per_sec : blk_per_sec - 1;
>>>
>>>                f2fs_down_write(&sbi->pin_sem);
>>>
>>
>>
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