2021-07-16 06:20:29

by Jingbo Xu

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

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 <[email protected]>
---
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

2021-07-16 16:20:57

by Darrick J. Wong

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

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 <[email protected]>
> ---
> 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
>

2021-07-19 01:48:07

by Jingbo Xu

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

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 <[email protected]>
>> ---
>> 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