Re: [PATCH] ceph: set FMODE_CAN_ODIRECT instead of a dummy direct_IO method

[Christoph Hellwig <hch@lst.de>]

On Tue, Jun 13, 2023 at 08:57:42AM +0800, Xiubo Li wrote:
>> +	if (S_ISREG(inode->i_mode))
>> +		file->f_mode |= FMODE_CAN_ODIRECT;
>>   
>
> Shouldn't we do the same in 'ceph_atomic_open()' too ?

Yes, probably.  Or I really need to press ahead and move the flag
to file operations..

>> --- a/fs/ceph/file.c
>> +++ b/fs/ceph/file.c
>> @@ -368,6 +368,8 @@ int ceph_open(struct inode *inode, struct file *file)
>>   	flags = file->f_flags & ~(O_CREAT|O_EXCL);
>>   	if (S_ISDIR(inode->i_mode))
>>   		flags = O_DIRECTORY;  /* mds likes to know */
>> +	if (S_ISREG(inode->i_mode))
>
> BTW, the commit a2ad63daa88b ("VFS: add FMODE_CAN_ODIRECT file flag") 
> doesn't check the S_ISREG, and I couldn't see this commit and NFS confine 
> it to regular files, is that okay ?

It doesn't have to.  ->direct_IO was previously set only for regular
files (and block devices in the block code).  So it makes sense to do
the same for the flag.