On Fri, Sep 01, 2017 at 12:21:49AM -0700, Christoph Hellwig wrote:
> On Thu, Aug 31, 2017 at 12:57:29PM -0700, Darrick J. Wong wrote:
> > TBH I like this less because now the responsibility for checking valid
> > inputs is split between xfs_ioctl_setattr_xflags and xfs_set_diflags.
> > I'd rather increase the function count by one than morph the setting
> > function into check-and-set.
>
> I'm not worried about the function count - I'm worried about duplicating
> the information of which flags are stored in di_flags2. With this patch
> we have one point where we can naturally check this. In your patch
> we need another define that needs to be kept uptodate.
>
> If you are worried about the check and set we could move the set into
> the caller, but to me that doesn't seem any cleaner. Example attached
> below:
>
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 9c0c7a920304..511cd7c830ab 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -931,16 +931,15 @@ xfs_ioc_fsgetxattr(
> return 0;
> }
>
> -STATIC void
> -xfs_set_diflags(
> +STATIC unsigned int
> +xfs_flags2diflags(
> struct xfs_inode *ip,
> unsigned int xflags)
> {
> - unsigned int di_flags;
> - uint64_t di_flags2;
> -
> /* can't set PREALLOC this way, just preserve it */
> - di_flags = (ip->i_d.di_flags & XFS_DIFLAG_PREALLOC);
> + unsigned int di_flags =
> + (ip->i_d.di_flags & XFS_DIFLAG_PREALLOC);
ip->i_d.di_flags is uint16_t, so di_flags ought to match, right?
Otherwise, I guess this looks ok, want to send it as a real patch?
--D
> +
> if (xflags & FS_XFLAG_IMMUTABLE)
> di_flags |= XFS_DIFLAG_IMMUTABLE;
> if (xflags & FS_XFLAG_APPEND)
> @@ -970,19 +969,24 @@ xfs_set_diflags(
> if (xflags & FS_XFLAG_EXTSIZE)
> di_flags |= XFS_DIFLAG_EXTSIZE;
> }
> - ip->i_d.di_flags = di_flags;
>
> - /* diflags2 only valid for v3 inodes. */
> - if (ip->i_d.di_version < 3)
> - return;
> + return di_flags;
> +}
> +
> +STATIC uint64_t
> +xfs_flags2diflags2(
> + struct xfs_inode *ip,
> + unsigned int xflags)
> +{
> + uint64_t di_flags2 =
> + (ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK);
>
> - di_flags2 = (ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK);
> if (xflags & FS_XFLAG_DAX)
> di_flags2 |= XFS_DIFLAG2_DAX;
> if (xflags & FS_XFLAG_COWEXTSIZE)
> di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
>
> - ip->i_d.di_flags2 = di_flags2;
> + return di_flags2;
> }
>
> STATIC void
> @@ -1022,6 +1026,7 @@ xfs_ioctl_setattr_xflags(
> struct fsxattr *fa)
> {
> struct xfs_mount *mp = ip->i_mount;
> + uint64_t di_flags2;
>
> /* Can't change realtime flag if any extents are allocated. */
> if ((ip->i_d.di_nextents || ip->i_delayed_blks) &&
> @@ -1052,7 +1057,14 @@ xfs_ioctl_setattr_xflags(
> !capable(CAP_LINUX_IMMUTABLE))
> return -EPERM;
>
> - xfs_set_diflags(ip, fa->fsx_xflags);
> + /* diflags2 only valid for v3 inodes. */
> + di_flags2 = xfs_flags2diflags(ip, fa->fsx_xflags);
> + if (di_flags2 && ip->i_d.di_version < 3)
> + return -EINVAL;
> +
> + ip->i_d.di_flags = xfs_flags2diflags(ip, fa->fsx_xflags);
> + ip->i_d.di_flags2 = di_flags2;
> +
> xfs_diflags_to_linux(ip);
> xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
> xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
> --
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