[PATCH] vfs: only allow SETFLAGS to set DAX flag on files and dirs

[PATCH] vfs: only allow SETFLAGS to set DAX flag on files and dirs

[Jeffle Xu]

This is similar to commit dbc77f31e58b ("vfs: only allow FSSETXATTR to
set DAX flag on files and dirs").

Though the underlying filesystems may have filtered invalid flags, e.g.,
ext4_mask_flags() called in ext4_fileattr_set(), also check it in VFS
layer.

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
---
 fs/ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 1e2204fa9963..1fe73e148e2d 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -835,7 +835,7 @@ static int fileattr_set_prepare(struct inode *inode,
 	 * It is only valid to set the DAX flag on regular files and
 	 * directories on filesystems.
 	 */
-	if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
+	if ((fa->fsx_xflags & FS_XFLAG_DAX || fa->flags & FS_DAX_FL) &&
 	    !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
 		return -EINVAL;
 
-- 
2.27.0

Re: [PATCH] vfs: only allow SETFLAGS to set DAX flag on files and dirs

[Darrick J. Wong]

On Fri, Jul 16, 2021 at 02:19:51PM +0800, Jeffle Xu wrote:
> This is similar to commit dbc77f31e58b ("vfs: only allow FSSETXATTR to
> set DAX flag on files and dirs").
> 
> Though the underlying filesystems may have filtered invalid flags, e.g.,
> ext4_mask_flags() called in ext4_fileattr_set(), also check it in VFS
> layer.
> 
> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
> ---
>  fs/ioctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ioctl.c b/fs/ioctl.c
> index 1e2204fa9963..1fe73e148e2d 100644
> --- a/fs/ioctl.c
> +++ b/fs/ioctl.c
> @@ -835,7 +835,7 @@ static int fileattr_set_prepare(struct inode *inode,
>  	 * It is only valid to set the DAX flag on regular files and
>  	 * directories on filesystems.
>  	 */
> -	if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
> +	if ((fa->fsx_xflags & FS_XFLAG_DAX || fa->flags & FS_DAX_FL) &&

I thought we always had to surround flag tests with separate
parentheses...?

--D

>  	    !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
>  		return -EINVAL;
>  
> -- 
> 2.27.0
> 

Re: [PATCH] vfs: only allow SETFLAGS to set DAX flag on files and dirs

[JeffleXu]

On 7/17/21 12:20 AM, Darrick J. Wong wrote:
> On Fri, Jul 16, 2021 at 02:19:51PM +0800, Jeffle Xu wrote:
>> This is similar to commit dbc77f31e58b ("vfs: only allow FSSETXATTR to
>> set DAX flag on files and dirs").
>>
>> Though the underlying filesystems may have filtered invalid flags, e.g.,
>> ext4_mask_flags() called in ext4_fileattr_set(), also check it in VFS
>> layer.
>>
>> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
>> ---
>>  fs/ioctl.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/fs/ioctl.c b/fs/ioctl.c
>> index 1e2204fa9963..1fe73e148e2d 100644
>> --- a/fs/ioctl.c
>> +++ b/fs/ioctl.c
>> @@ -835,7 +835,7 @@ static int fileattr_set_prepare(struct inode *inode,
>>  	 * It is only valid to set the DAX flag on regular files and
>>  	 * directories on filesystems.
>>  	 */
>> -	if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
>> +	if ((fa->fsx_xflags & FS_XFLAG_DAX || fa->flags & FS_DAX_FL) &&
> 
> I thought we always had to surround flag tests with separate
> parentheses...?

Thanks.

The 'bitwise and' has a higher priority than 'logical or'. But for sure
I can add parentheses to make it more readable and precise.

-- 
Thanks,
Jeffle