On Tue, Jan 27, 2015 at 02:14:46PM +1100, Dave Chinner wrote:
> From: Iustin Pop <iustin@xxxxxxxxx>
>
> Currently, the ioctl handling code for XFS_IOC_FSSETXATTR treats all
> targets as regular files: it refuses to change the extent size if
> extents are allocated. This is wrong for directories, as there the
> extent size is only used as a default for children.
>
> The patch fixes this issue and improves validation of flag
> combinations:
>
> - only disallow extent size changes after extents have been allocated
> for regular files
> - only allow XFS_XFLAG_EXTSIZE for regular files
> - only allow XFS_XFLAG_EXTSZINHERIT for directories
> - automatically clear the flags if the extent size is zero
>
> Thanks to Dave Chinner for guidance on the proper fix for this issue.
>
> [dchinner: ported changes onto cleanup series. Makes changes clear
> and obvious.]
> [dchinner: added comments documenting validity checking rules.]
>
> Signed-off-by: Iustin Pop <iustin@xxxxxxxxx>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> fs/xfs/xfs_ioctl.c | 39 +++++++++++++++++++++++++--------------
> 1 file changed, 25 insertions(+), 14 deletions(-)
>
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 561d142..5d9dc69 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1098,6 +1098,20 @@ out_cancel:
> return ERR_PTR(error);
> }
>
> +/*
> + * extent size hint validation is somewhat cumbersome. Rules are:
> + *
> + * 1. extent size hint is only valid for directories and regular files
> + * 2. XFS_XFLAG_EXTSIZE is only valid for regular files
> + * 3. XFS_XFLAG_EXTSZINHERIT is only valid for directories.
> + * 4. can only be changed on regular files if no extents are allocated
> + * 5. can be changed on directories at any time
> + * 6. extsize hint of 0 turns off hints, clears inode flags.
> + * 7. Extent size must be a multiple of the appropriate block size.
> + * 8. for non-realtime files, the extent size hint must be limited
> + * to half the AG size to avoid alignment extending the extent beyond the
> + * limits of the AG.
> + */
> int
> xfs_ioctl_setattr_check_extsize(
> struct xfs_inode *ip,
> @@ -1105,20 +1119,17 @@ xfs_ioctl_setattr_check_extsize(
> {
> struct xfs_mount *mp = ip->i_mount;
>
> - /* Can't change extent size if any extents are allocated. */
> - if (ip->i_d.di_nextents &&
> + if ((fa->fsx_xflags & XFS_XFLAG_EXTSIZE) && !S_ISREG(ip->i_d.di_mode))
> + return -EINVAL;
> +
> + if ((fa->fsx_xflags & XFS_XFLAG_EXTSZINHERIT) &&
> + !S_ISDIR(ip->i_d.di_mode))
> + return -EINVAL;
> +
> + if (S_ISREG(ip->i_d.di_mode) && ip->i_d.di_nextents &&
> ((ip->i_d.di_extsize << mp->m_sb.sb_blocklog) != fa->fsx_extsize))
> return -EINVAL;
>
> - /*
> - * Extent size must be a multiple of the appropriate block size, if set
> - * at all. It must also be smaller than the maximum extent size
> - * supported by the filesystem.
> - *
> - * Also, for non-realtime files, limit the extent size hint to half the
> - * size of the AGs in the filesystem so alignment doesn't result in
> - * extents larger than an AG.
> - */
> if (fa->fsx_extsize != 0) {
> xfs_extlen_t size;
> xfs_fsblock_t extsize_fsb;
> @@ -1138,7 +1149,9 @@ xfs_ioctl_setattr_check_extsize(
>
> if (fa->fsx_extsize % size)
> return -EINVAL;
> - }
> + } else
> + fa->fsx_xflags &= ~(XFS_XFLAG_EXTSIZE | XFS_XFLAG_EXTSZINHERIT);
> +
> return 0;
> }
>
> @@ -1169,8 +1182,6 @@ xfs_ioctl_setattr_check_projid(
> return 0;
> }
>
> -
> -
> STATIC int
> xfs_ioctl_setattr(
> xfs_inode_t *ip,
> --
> 2.0.0
>
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