2018-02-15 21:40:54

by Dave Jiang

Subject: [PATCH v5 3/3] xfs: reject removal of realtime flag when datadev doesn't support DAX

In a situation where the rt_dev is DAX and data_dev is not DAX, if the user
requests to remove the realtime flag via ioctl we can no longer support DAX
for that file. Dynamic changing of S_DAX on the inode is not supported due
to various complications in the existing implementation. Therefore until we
address the dynamic S_DAX change issues, we must disallow realtime flag
being removed.

Signed-off-by: Dave Jiang <[email protected]>
---
fs/xfs/xfs_ioctl.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 2c70a0a4f59f..59ec742de692 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1030,6 +1030,20 @@ xfs_ioctl_setattr_xflags(
{
struct xfs_mount *mp = ip->i_mount;
uint64_t di_flags2;
+ struct inode *inode = VFS_I(ip);
+ struct super_block *sb = inode->i_sb;
+
+ /*
+ * In the case that the inode is realtime, and we are trying to remove
+ * the realtime flag, and the rtdev supports DAX but the datadev does
+ * not support DAX, we can't allow the realtime flag to be removed
+ * since we do not support dynamic S_DAX flag removal yet.
+ */
+ if ((XFS_IS_REALTIME_INODE(ip)) &&
+ !(fa->fsx_xflags & FS_XFLAG_REALTIME) &&
+ bdev_dax_supported(mp->m_rtdev_targp->bt_bdev, sb->s_blocksize) &&
+ !bdev_dax_supported(mp->m_ddev_targp->bt_bdev, sb->s_blocksize))
+ return -ENOTSUPP;

/* Can't change realtime flag if any extents are allocated. */
if ((ip->i_d.di_nextents || ip->i_delayed_blks) &&

2018-02-15 21:47:13

by Christoph Hellwig

Subject: Re: [PATCH v5 3/3] xfs: reject removal of realtime flag when datadev doesn't support DAX

> + if ((XFS_IS_REALTIME_INODE(ip)) &&

No need for the inner braces.

Except for that the whole series looks fine to me.

2018-02-15 22:44:50

by Dave Jiang

Subject: Re: [PATCH v5 3/3] xfs: reject removal of realtime flag when datadev doesn't support DAX

On 02/15/2018 02:47 PM, Christoph Hellwig wrote:
>> + if ((XFS_IS_REALTIME_INODE(ip)) &&
>
> No need for the inner braces.

Ok I'll fix

>
> Except for that the whole series looks fine to me.
>

Can I add your reviewed-by? Thanks for reviewing.

2018-02-15 22:48:39

by Christoph Hellwig

Subject: Re: [PATCH v5 3/3] xfs: reject removal of realtime flag when datadev doesn't support DAX

On Thu, Feb 15, 2018 at 03:44:48PM -0700, Dave Jiang wrote:
> >
> > Except for that the whole series looks fine to me.
> >
>
> Can I add your reviewed-by? Thanks for reviewing.

Yes:

Reviewed-by: Christoph Hellwig <[email protected]>