xfs: introduce per-inode DAX enablement
Rather than just being able to turn DAX on and off via a mount
option, some applications may only want to enable DAX for certain
performance critical files in a filesystem.
This patch introduces a new inode flag to enable DAX in the v3 inode
di_flags2 field. It adds support for setting and clearing flags in
the di_flags2 field via the XFS_IOC_FSSETXATTR ioctl, and sets the
S_DAX inode flag appropriately when it is seen.
When this flag is set on a directory, it acts as an "inherit flag".
That is, inodes created in the directory will automatically inherit
the on-disk inode DAX flag, enabling administrators to set up
directory heirarchies that automatically use DAX. Setting this flag
on an empty root directory will make the entire filesystem use DAX
by default.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 94b35eb3..478d04e 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -945,6 +945,7 @@
unsigned int xflags)
{
unsigned int di_flags;
+ uint64_t di_flags2;
/* can't set PREALLOC this way, just preserve it */
di_flags = (ip->i_d.di_flags & XFS_DIFLAG_PREALLOC);
@@ -977,8 +978,18 @@
if (xflags & FS_XFLAG_EXTSIZE)
di_flags |= XFS_DIFLAG_EXTSIZE;
}
-
ip->i_d.di_flags = di_flags;
+
+ /* diflags2 only valid for v3 inodes. */
+ if (ip->i_d.di_version < 3)
+ return;
+
+ di_flags2 = 0;
+ if (xflags & FS_XFLAG_DAX)
+ di_flags2 |= XFS_DIFLAG2_DAX;
+
+ ip->i_d.di_flags2 = di_flags2;
+
}
STATIC void
@@ -1004,6 +1015,11 @@
inode->i_flags |= S_NOATIME;
else
inode->i_flags &= ~S_NOATIME;
+ if (xflags & FS_XFLAG_DAX)
+ inode->i_flags |= S_DAX;
+ else
+ inode->i_flags &= ~S_DAX;
+
}
static int