[RFC][PATCH 2/4] xfs: support RENAME_VFS_DTYPE flag

[Amir Goldstein <amir73il@gmail.com>]

If caller provided the target dtype to use and indicated that with
rename() flag RENAME_VFS_DTYPE, use RENAME_DT_MODE(flags) instead
of inode->i_mode to determine the value of dtype to store in the
directory entry.

Adding this functionality to official xfs code will require to add
a new feature flag to xfs directry naming on-disk format.

Without that new feature flag, xfs_repair will report that custom
dtype as a warning and set it back to the dtype value according to mode.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/xfs/libxfs/xfs_dir2.c |  1 +
 fs/xfs/xfs_iops.c        | 11 ++++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
index 984530e..71c6b2b 100644
--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -49,6 +49,7 @@ const unsigned char xfs_dtype_to_ftype[DT_MAX] = {
 	[DT_FIFO]   = XFS_DIR3_FT_FIFO,
 	[DT_SOCK]   = XFS_DIR3_FT_SOCK,
 	[DT_LNK]    = XFS_DIR3_FT_SYMLINK,
+	[DT_WHT]    = XFS_DIR3_FT_WHT,
 };
 
 /*
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index d2da9ca..8574155 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -394,19 +394,24 @@ xfs_vn_rename(
 	unsigned int	flags)
 {
 	struct inode	*new_inode = d_inode(ndentry);
-	int		omode = 0;
+	int		omode = 0, nmode = 0;
 	struct xfs_name	oname;
 	struct xfs_name	nname;
 
-	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
+	if (flags & ~RENAME_VFS_MASK)
 		return -EINVAL;
 
 	/* if we are exchanging files, we need to set i_mode of both files */
 	if (flags & RENAME_EXCHANGE)
 		omode = d_inode(ndentry)->i_mode;
+	/* if requested, use provided dtype for target */
+	if (flags & RENAME_VFS_DTYPE)
+		nmode = RENAME_DT_MODE(flags);
+	else
+		nmode = d_inode(odentry)->i_mode;
 
 	xfs_dentry_to_name(&oname, odentry, omode);
-	xfs_dentry_to_name(&nname, ndentry, d_inode(odentry)->i_mode);
+	xfs_dentry_to_name(&nname, ndentry, nmode);
 
 	return xfs_rename(XFS_I(odir), &oname, XFS_I(d_inode(odentry)),
 			  XFS_I(ndir), &nname,
-- 
2.7.4