@@ -1008,7 +1008,7 @@ xfs_diflags_to_linux(
inode->i_flags |= S_NOATIME;
else
inode->i_flags &= ~S_NOATIME;
- if (xflags & FS_XFLAG_DAX)
+ if ((xflags & FS_XFLAG_DAX) || (ip->i_mount->m_flags & XFS_MOUNT_DAX))
inode->i_flags |= S_DAX;
else
inode->i_flags &= ~S_DAX;
@@ -1091,7 +1091,14 @@ xfs_ioctl_setattr_dax_invalidate(
return -EINVAL;
}
- /* If the DAX state is not changing, we have nothing to do here. */
+ /*
+ * If the DAX state is not changing, we have nothing to do here. If
+ * the DAX mount option was used we will update the DAX inode flag as
+ * the user requested but we will continue to use DAX for I/O and page
+ * faults regardless of how the inode flag is set.
+ */
+ if (ip->i_mount->m_flags & XFS_MOUNT_DAX)
+ return 0;
if ((fa->fsx_xflags & FS_XFLAG_DAX) && IS_DAX(inode))
return 0;
if (!(fa->fsx_xflags & FS_XFLAG_DAX) && !IS_DAX(inode))
The current code has an issue where the user can't reliably tell whether or not DAX is being used to service page faults and I/O when the DAX mount option is used. In this case each inode within the mounted filesystem starts with S_DAX set due to the mount option, but it can be cleared if someone touches the individual inode flag. For example: # mount | grep dax /dev/pmem0 on /mnt type xfs (rw,relatime,seclabel,attr2,dax,inode64,sunit=4096,swidth=4096,noquota) # touch /mnt/a /mnt/b # both files currently use DAX # xfs_io -c "lsattr" /mnt/* # neither has the DAX inode option set ----------e----- /mnt/a ----------e----- /mnt/b # xfs_io -c "chattr -x" /mnt/a # this clears S_DAX for /mnt/a # xfs_io -c "lsattr" /mnt/* ----------e----- /mnt/a ----------e----- /mnt/b We end up with both /mnt/a and /mnt/b looking identical from the point of view of the mount option and from lsattr, but one is using DAX and the other is not. Fix this by always doing DAX I/O when either the mount option is set or when the DAX inode flag is set. This means that DAX will always be used for all inodes on a filesystem mounted with -o dax, making the usage reliable and detectable. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> CC: stable@vger.kernel.org --- fs/xfs/xfs_ioctl.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)