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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: Iustin Pop <iustin@k1024.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Iustin Pop 2015-02-02 10:26:26 +11:00 committed by Dave Chinner
parent 23bd0735cf
commit 9b94fcc398
1 changed files with 25 additions and 14 deletions
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39
fs/xfs/xfs_ioctl.c
View File

@ -1098,6 +1098,20 @@ xfs_ioctl_setattr_get_trans(
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,