On Wed, Apr 22, 2020 at 07:30:49AM +1000, Dave Chinner wrote: > On Tue, Apr 21, 2020 at 01:31:40PM -0700, Darrick J. Wong wrote: > > On Tue, Apr 21, 2020 at 12:17:52PM -0700, ira.weiny@xxxxxxxxx wrote: > > > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > > > Because of the separation of FS_XFLAG_DAX from S_DAX and the delayed > > > setting of S_DAX, data invalidation no longer needs to happen when > > > FS_XFLAG_DAX is changed. > > > > > > Change xfs_ioctl_setattr_dax_invalidate() to be > > > xfs_ioctl_dax_check_set_cache() and alter the code to reflect the new > > > functionality. > > > > > > Furthermore, we no longer need the locking so we remove the join_flags > > > logic. > > > > > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > > > --- > > > Changes from V8: > > > Change name of function to xfs_ioctl_dax_check_set_cache() > > > Update commit message > > > Fix bit manipulations > > > > > > 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 | 108 +++++++++------------------------------------ > > > 1 file changed, 20 insertions(+), 88 deletions(-) > > > > > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > > > index 104495ac187c..b87b571a6748 100644 > > > --- a/fs/xfs/xfs_ioctl.c > > > +++ b/fs/xfs/xfs_ioctl.c > > > @@ -1245,64 +1245,26 @@ xfs_ioctl_setattr_xflags( > > > return 0; > > > } > > > > > > -/* > > > - * 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. > > > - */ > > > -static int > > > -xfs_ioctl_setattr_dax_invalidate( > > > +static void > > > +xfs_ioctl_dax_check_set_cache( > > > > That's a ... strange name. Set cache on what? > > > > Oh, this is the function that sets I_DONTCACHE if an FS_XFLAG_DAX change > > could have an immediate effect on S_DAX (assuming no other users). What > > do you think of the following? > > > > /* > > * If a change to FS_XFLAG_DAX will result in an change to S_DAX > > * the next time the incore inode is initialized, set the VFS > > * I_DONTCACHE flag to try to hurry that along. > > */ > > static void > > xfs_ioctl_try_change_vfs_dax(...) > > That doesn't seem any better. This is a preparation function now, in > that it can't fail and doesn't change the outcome of the operation > being performed. So, IMO, calling it something like > xfs_ioctl_setattr_prepare_dax() would be a better name for it. But it does potentially (after a check) set I_DONTCACHE. What about? xfs_ioctl_dax_check_set_dontcache()? Ira > > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx
