Commit 9b94fcc3 authored by Iustin Pop's avatar Iustin Pop Committed by Dave Chinner
Browse files

xfs: fix behaviour of XFS_IOC_FSSETXATTR on directories 



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: default avatarIustin Pop <iustin@k1024.org>
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 23bd0735

fs/xfs/xfs_ioctl.c

+25 −14
Original line number Diff line number Diff line
@@ -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,

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