ufs_trunc_...indirect(): pass the array of indices instead of offsets

rather than bitslicing the offset just formed as sum of shifted indices,
pass the array of those indices itself.  NULL is used as equivalent
of "all zeroes" (== free the entire branch).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/ufs/inode.c

@@ -1069,7 +1069,7 @@ static void ufs_trunc_direct(struct inode *inode)
 }
 
 
-static void ufs_trunc_indirect(struct inode *inode, unsigned from, void *p)
+static void ufs_trunc_indirect(struct inode *inode, unsigned *offsets, void *p)
 {
 	struct super_block *sb = inode->i_sb;
 	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
@@ -1077,7 +1077,8 @@ static void ufs_trunc_indirect(struct inode *inode, unsigned from, void *p)
 	void *ind;
 	u64 tmp, frag_to_free = 0;
 	unsigned free_count = 0;
-	bool to_free = !from;
+	unsigned from = offsets ? *offsets : 0;
+	bool to_free = !offsets || !from;
 	unsigned i;
 
 	tmp = ufs_data_ptr_to_cpu(sb, p);
@@ -1134,16 +1135,15 @@ static void ufs_trunc_indirect(struct inode *inode, unsigned from, void *p)
 	ubh_brelse (ind_ubh);
 }
 
-static void ufs_trunc_dindirect(struct inode *inode, u64 offset, void *p)
+static void ufs_trunc_dindirect(struct inode *inode, unsigned *offsets, void *p)
 {
 	struct super_block *sb = inode->i_sb;
 	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
 	struct ufs_buffer_head *dind_bh;
 	u64 tmp;
 	void *dind;
-	bool free_it = !offset;
-	unsigned dindirect_block = offset >> uspi->s_apbshift;
-	unsigned from = offset & uspi->s_apbmask;
+	bool free_it = !offsets || !(offsets[0] || offsets[1]);
+	unsigned dindirect_block = offsets ? *offsets++ : 0;
 	unsigned i;
 
 	tmp = ufs_data_ptr_to_cpu(sb, p);
@@ -1157,12 +1157,12 @@ static void ufs_trunc_dindirect(struct inode *inode, u64 offset, void *p)
 		return;
 	}
 
-	for (i = dindirect_block ; i < uspi->s_apb ; i++, from = 0) {
+	for (i = dindirect_block ; i < uspi->s_apb ; i++, offsets = NULL) {
 		dind = ubh_get_data_ptr(uspi, dind_bh, i);
 		tmp = ufs_data_ptr_to_cpu(sb, dind);
 		if (!tmp)
 			continue;
-		ufs_trunc_indirect(inode, from, dind);
+		ufs_trunc_indirect(inode, offsets, dind);
 		ubh_mark_buffer_dirty(dind_bh);
 	}
 
@@ -1182,7 +1182,7 @@ static void ufs_trunc_dindirect(struct inode *inode, u64 offset, void *p)
 	ubh_brelse (dind_bh);
 }
 
-static void ufs_trunc_tindirect(struct inode *inode, u64 offset)
+static void ufs_trunc_tindirect(struct inode *inode, unsigned *offsets)
 {
 	struct super_block *sb = inode->i_sb;
 	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
@@ -1190,12 +1190,10 @@ static void ufs_trunc_tindirect(struct inode *inode, u64 offset)
 	struct ufs_buffer_head * tind_bh;
 	u64 tmp;
 	void *tind, *p;
-	bool free_it = !offset;
-	unsigned tindirect_block = offset >> uspi->s_2apbshift;
+	bool free_it = !offsets || !(offsets[0] || offsets[1] || offsets[2]);
+	unsigned tindirect_block = offsets ? *offsets++ : 0;
 	unsigned i;
 
-	offset -= tindirect_block << uspi->s_2apbshift;
-
 	p = ufs_get_direct_data_ptr(uspi, ufsi, UFS_TIND_BLOCK);
 	if (!(tmp = ufs_data_ptr_to_cpu(sb, p)))
 		return;
@@ -1207,9 +1205,9 @@ static void ufs_trunc_tindirect(struct inode *inode, u64 offset)
 		return;
 	}
 
-	for (i = tindirect_block ; i < uspi->s_apb ; i++, offset = 0) {
+	for (i = tindirect_block ; i < uspi->s_apb ; i++, offsets = NULL) {
 		tind = ubh_get_data_ptr(uspi, tind_bh, i);
-		ufs_trunc_dindirect(inode, offset, tind);
+		ufs_trunc_dindirect(inode, offsets, tind);
 		ubh_mark_buffer_dirty(tind_bh);
 	}
 	if (free_it) {
@@ -1310,30 +1308,26 @@ static void __ufs_truncate_blocks(struct inode *inode)
 	switch (depth) {
 	case 1:
 		ufs_trunc_direct(inode);
-		ufs_trunc_indirect(inode, 0,
+		ufs_trunc_indirect(inode, NULL,
 			   ufs_get_direct_data_ptr(uspi, ufsi, UFS_IND_BLOCK));
-		ufs_trunc_dindirect(inode, 0,
+		ufs_trunc_dindirect(inode, NULL,
 			    ufs_get_direct_data_ptr(uspi, ufsi, UFS_DIND_BLOCK));
-		ufs_trunc_tindirect(inode, 0);
+		ufs_trunc_tindirect(inode, NULL);
 		break;
 	case 2:
-		ufs_trunc_indirect(inode, offsets[1],
+		ufs_trunc_indirect(inode, offsets + 1,
 			   ufs_get_direct_data_ptr(uspi, ufsi, UFS_IND_BLOCK));
-		ufs_trunc_dindirect(inode, 0,
+		ufs_trunc_dindirect(inode, NULL,
 			    ufs_get_direct_data_ptr(uspi, ufsi, UFS_DIND_BLOCK));
-		ufs_trunc_tindirect(inode, 0);
+		ufs_trunc_tindirect(inode, NULL);
 		break;
 	case 3:
-		ufs_trunc_dindirect(inode,
-			    (offsets[1] << uspi->s_apbshift) + offsets[2],
+		ufs_trunc_dindirect(inode, offsets + 1,
 			    ufs_get_direct_data_ptr(uspi, ufsi, UFS_DIND_BLOCK));
-		ufs_trunc_tindirect(inode, 0);
+		ufs_trunc_tindirect(inode, NULL);
 		break;
 	case 4:
-		ufs_trunc_tindirect(inode,
-			   (offsets[1] << uspi->s_2apbshift) +
-			   (offsets[2] << uspi->s_apbshift) +
-			   offsets[3]);
+		ufs_trunc_tindirect(inode, offsets + 1);
 	}
 	ufsi->i_lastfrag = DIRECT_FRAGMENT;
 	mutex_unlock(&ufsi->truncate_mutex);