On Mon, Apr 20, 2020 at 12:31:31PM +1000, Dave Chinner wrote: > On Tue, Apr 14, 2020 at 11:45:22PM -0700, ira.weiny@xxxxxxxxx wrote: > > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > We only support changing FS_XFLAG_DAX on directories. Files get their > > flag from the parent directory on creation only. So no data > > invalidation needs to happen. > > > > Alter the xfs_ioctl_setattr_dax_invalidate() to be > > xfs_ioctl_setattr_dax_validate(). xfs_ioctl_setattr_dax_validate() now > > validates that any FS_XFLAG_DAX change is ok. > > > > This also allows use to remove the join_flags logic. > > > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > --- > > Changes from V7: > > Use new flag_inode_dontcache() > > Skip don't cache if mount over ride is active. > > > > Changes from v6: > > Fix completely broken implementation and update commit message. > > Use the new VFS layer I_DONTCACHE to facilitate inode eviction > > and S_DAX changing on drop_caches > > > > Changes from v5: > > New patch > > --- > > fs/xfs/xfs_ioctl.c | 105 +++++++++------------------------------------ > > 1 file changed, 20 insertions(+), 85 deletions(-) > > > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > > index c6cd92ef4a05..75d4a830ef38 100644 > > --- a/fs/xfs/xfs_ioctl.c > > +++ b/fs/xfs/xfs_ioctl.c > > @@ -1145,63 +1145,28 @@ xfs_ioctl_setattr_xflags( > > } > > > > /* > > - * If we are changing DAX flags, we have to ensure the file is clean and any > > - * cached objects in the address space are invalidated and removed. This > > - * requires us to lock out other IO and page faults similar to a truncate > > - * operation. The locks need to be held until the transaction has been committed > > - * so that the cache invalidation is atomic with respect to the DAX flag > > - * manipulation. > > + * Mark inodes with a changing FS_XFLAG_DAX, I_DONTCACHE > > That describes what the code is doing, not why. I'll remove the comment. > > > */ > > -static int > > +static void > > xfs_ioctl_setattr_dax_invalidate( > > struct xfs_inode *ip, > > - struct fsxattr *fa, > > - int *join_flags) > > + struct fsxattr *fa) > > It's not an invalidation function anymore, so needs a name change. Done. > > > - if (!(fa->fsx_xflags & FS_XFLAG_DAX) && !IS_DAX(inode)) > > - return 0; > > + struct xfs_mount *mp = ip->i_mount; > > + struct inode *inode = VFS_I(ip); > > > > if (S_ISDIR(inode->i_mode)) > > - return 0; > > - > > - /* lock, flush and invalidate mapping in preparation for flag change */ > > - xfs_ilock(ip, XFS_MMAPLOCK_EXCL | XFS_IOLOCK_EXCL); > > - error = filemap_write_and_wait(inode->i_mapping); > > - if (error) > > - goto out_unlock; > > - error = invalidate_inode_pages2(inode->i_mapping); > > - if (error) > > - goto out_unlock; > > + return; > > > > - *join_flags = XFS_MMAPLOCK_EXCL | XFS_IOLOCK_EXCL; > > - return 0; > > - > > -out_unlock: > > - xfs_iunlock(ip, XFS_MMAPLOCK_EXCL | XFS_IOLOCK_EXCL); > > - return error; > > + if (mp->m_flags & XFS_MOUNT_DAX_ALWAYS || > > + mp->m_flags & XFS_MOUNT_DAX_NEVER) > > + return; > > if (mp->m_flags & (XFS_MOUNT_DAX_ALWAYS | XFS_MOUNT_DAX_NEVER)) > return; > > + if (((fa->fsx_xflags & FS_XFLAG_DAX) && > > + !(ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)) || > > + (!(fa->fsx_xflags & FS_XFLAG_DAX) && > > + (ip->i_d.di_flags2 & XFS_DIFLAG2_DAX))) > > + flag_inode_dontcache(inode); > > This doesn't set the XFS inode's "don't cache" flag, despite it > having one that serves exactly the same purpose. IOWs, if the XFS_IDONTCACHE > flag is now redundant, please replace it's current usage with this new flag > and get rid of the XFS inode flag. i.e. the only place we set XFS_IDONTCACHE > can be replaced with a call to this mark_inode_dontcache() call... I agree, and I would have removed XFS_IDONTCACHE, except I was not convinced that XFS_IDONTCACHE was redundant. Currently XFS_IDONTCACHE can be cleared if the inode is found in the cache and I was unable to convince myself that it would be ok to remove it. I mentioned this to Darrick in V7. https://lore.kernel.org/lkml/20200413194432.GD1649878@xxxxxxxxxxxxxxxxxxxxxxxxx/ What am I missing with this code? xfs_iget_cache_hit(): ... if (!(flags & XFS_IGET_INCORE)) xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE); ... Why is XFS_IDONTCACHE not 'sticky'? And why does xfs_iget_cache_hit() clear it rather than fail when XFS_IDONTCACHE is set? Ira > > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx
