[RFC PATCH V2 04/12] fs/xfs: Clean up DAX support check

[ira . weiny]

From: Ira Weiny <ira.weiny@xxxxxxxxx>

Rather than open coding xfs_inode_supports_dax() in
xfs_ioctl_setattr_dax_invalidate() export xfs_inode_supports_dax() and
call it in preparation for swapping dax flags.

This also means updating xfs_inode_supports_dax() to return true for a
directory.

Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
 fs/xfs/xfs_ioctl.c | 16 +++-------------
 fs/xfs/xfs_iops.c  |  8 ++++++--
 fs/xfs/xfs_iops.h  |  2 ++
 3 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index fe37708cea8f..b5e00b67c297 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1176,23 +1176,13 @@ xfs_ioctl_setattr_dax_invalidate(
 	int			*join_flags)
 {
 	struct inode		*inode = VFS_I(ip);
-	struct super_block	*sb = inode->i_sb;
 	int			error;
 
 	*join_flags = 0;
 
-	/*
-	 * It is only valid to set the DAX flag on regular files and
-	 * directories on filesystems where the block size is equal to the page
-	 * size. On directories it serves as an inherited hint so we don't
-	 * have to check the device for dax support or flush pagecache.
-	 */
-	if (fa->fsx_xflags & FS_XFLAG_DAX) {
-		struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
-
-		if (!bdev_dax_supported(target->bt_bdev, sb->s_blocksize))
-			return -EINVAL;
-	}
+	if ((fa->fsx_xflags & FS_XFLAG_DAX) == FS_XFLAG_DAX &&
+	    !xfs_inode_supports_dax(ip))
+		return -EINVAL;
 
 	/* If the DAX state is not changing, we have nothing to do here. */
 	if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 0a0ea90259e9..d6843cdb51d0 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1244,14 +1244,18 @@ xfs_inode_mount_is_dax(
 }
 
 /* Figure out if this file actually supports DAX. */
-static bool
+bool
 xfs_inode_supports_dax(
 	struct xfs_inode	*ip)
 {
 	struct xfs_mount	*mp = ip->i_mount;
 
 	/* Only supported on non-reflinked files. */
-	if (!S_ISREG(VFS_I(ip)->i_mode) || xfs_is_reflink_inode(ip))
+	if (xfs_is_reflink_inode(ip))
+		return false;
+
+	/* Only supported on regular files and directories. */
+	if (!(S_ISREG(VFS_I(ip)->i_mode) || S_ISDIR(VFS_I(ip)->i_mode)))
 		return false;
 
 	/* Block size must match page size */
diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
index 4d24ff309f59..f24fec8de1d6 100644
--- a/fs/xfs/xfs_iops.h
+++ b/fs/xfs/xfs_iops.h
@@ -24,4 +24,6 @@ extern int xfs_setattr_nonsize(struct xfs_inode *ip, struct iattr *vap,
 extern int xfs_vn_setattr_nonsize(struct dentry *dentry, struct iattr *vap);
 extern int xfs_vn_setattr_size(struct dentry *dentry, struct iattr *vap);
 
+extern bool xfs_inode_supports_dax(struct xfs_inode *ip);
+
 #endif /* __XFS_IOPS_H__ */
-- 
2.21.0