On 3/25/25 14:31, Zhiguo Niu wrote:
> Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
> 于2025年3月24日周一 19:36写道：
>>
>> This patch uses i_sem to protect access/update on f2fs_inode_info.flag
>> in finish_preallocate_blocks(), it avoids grabbing inode_lock() in
>> each open().
>>
>> Signed-off-by: Chao Yu <c...@kernel.org>
>> ---
>> fs/f2fs/file.c | 40 +++++++++++++++++++++++-----------------
>> 1 file changed, 23 insertions(+), 17 deletions(-)
>>
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index abbcbb5865a3..bb6ba3269de0 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -554,19 +554,24 @@ static int f2fs_file_mmap(struct file *file, struct
>> vm_area_struct *vma)
>>
>> static int finish_preallocate_blocks(struct inode *inode)
>> {
>> - int ret;
>> + int ret = 0;
>> + bool opened;
>>
>> - inode_lock(inode);
>> - if (is_inode_flag_set(inode, FI_OPENED_FILE)) {
>> - inode_unlock(inode);
>> + f2fs_down_read(&F2FS_I(inode)->i_sem);
>> + opened = is_inode_flag_set(inode, FI_OPENED_FILE);
>> + f2fs_up_read(&F2FS_I(inode)->i_sem);
>> + if (opened)
>> return 0;
>> - }
>>
>> - if (!file_should_truncate(inode)) {
>> - set_inode_flag(inode, FI_OPENED_FILE);
>> - inode_unlock(inode);
>> - return 0;
>> - }
>> + inode_lock(inode);
>> + f2fs_down_read(&F2FS_I(inode)->i_sem);
>> + opened = is_inode_flag_set(inode, FI_OPENED_FILE);
>> + f2fs_up_read(&F2FS_I(inode)->i_sem);
> Hi Chao,
> F2FS_I(inode)->i_sem is not needed for this judgment FI_OPENED_FILE area?
> because inode_lock has been hold and this is a write lock, if process
> A get inode_lock,
> other proccesses will be blocked inode_lock until inode_unlock with
> FI_OPENED_FILE been set?
> how do you think?
Zhiguo,
Agreed, let me update it. Thank you.
Thanks,
> thanks！
>> + if (opened)
>> + goto out_unlock;
>> +
>> + if (!file_should_truncate(inode))
>> + goto out_update;
>>
>> f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>> filemap_invalidate_lock(inode->i_mapping);
>> @@ -576,16 +581,17 @@ static int finish_preallocate_blocks(struct inode
>> *inode)
>>
>> filemap_invalidate_unlock(inode->i_mapping);
>> f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>> -
>> - if (!ret)
>> - set_inode_flag(inode, FI_OPENED_FILE);
>> -
>> - inode_unlock(inode);
>> if (ret)
>> - return ret;
>> + goto out_unlock;
>>
>> file_dont_truncate(inode);
>> - return 0;
>> +out_update:
>> + f2fs_down_write(&F2FS_I(inode)->i_sem);
>> + set_inode_flag(inode, FI_OPENED_FILE);
>> + f2fs_up_write(&F2FS_I(inode)->i_sem);
>> +out_unlock:
>> + inode_unlock(inode);
>> + return ret;
>> }
>>
>> static int f2fs_file_open(struct inode *inode, struct file *filp)
>> --
>> 2.48.1
>>
>>
>>
>> _______________________________________________
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>> Linux-f2fs-devel@lists.sourceforge.net
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