ufs_trunc_..indirect(): more massage towards unifying

Instead of manually checking that the array contains only zeroes,
find the position of the last non-zero (in __ufs_truncate(), where
we can conveniently do that) and use that to tell if there's
any non-zero in the array tail passed to ufs_trunc_...indirect().

The goal of all that clumsiness is to get fold these functions
together.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 26 insertions, 17 deletions

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 34d8dac4fe8b..e90266a221b8 100644
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -1069,7 +1069,7 @@ next1:
 }
 
 
-static void ufs_trunc_indirect(struct inode *inode, unsigned *offsets, void *p)
+static void ufs_trunc_indirect(struct inode *inode, unsigned *offsets, int depth2, void *p)
 {
         struct super_block *sb = inode->i_sb;
         struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
@@ -1078,7 +1078,7 @@ static void ufs_trunc_indirect(struct inode *inode, unsigned *offsets, void *p)
         u64 tmp, frag_to_free = 0;
         unsigned free_count = 0;
         unsigned from = offsets ? *offsets : 0;
-        bool to_free = !offsets || !from;
+        bool to_free = !offsets || !depth2;
         unsigned i;
 
         tmp = ufs_data_ptr_to_cpu(sb, p);
@@ -1135,14 +1135,14 @@ static void ufs_trunc_indirect(struct inode *inode, unsigned *offsets, void *p)
         ubh_brelse (ind_ubh);
 }
 
-static void ufs_trunc_dindirect(struct inode *inode, unsigned *offsets, void *p)
+static void ufs_trunc_dindirect(struct inode *inode, unsigned *offsets, int depth2, 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 = !offsets || !(offsets[0] || offsets[1]);
+        bool free_it = !offsets || !depth2;
         unsigned dindirect_block = offsets ? *offsets++ : 0;
         unsigned i;
 
@@ -1162,7 +1162,7 @@ static void ufs_trunc_dindirect(struct inode *inode, unsigned *offsets, void *p)
                 tmp = ufs_data_ptr_to_cpu(sb, dind);
                 if (!tmp)
                         continue;
-                ufs_trunc_indirect(inode, offsets, dind);
+                ufs_trunc_indirect(inode, offsets, depth2 - 1, dind);
                 ubh_mark_buffer_dirty(dind_bh);
         }
 
@@ -1182,7 +1182,7 @@ static void ufs_trunc_dindirect(struct inode *inode, unsigned *offsets, void *p)
         ubh_brelse (dind_bh);
 }
 
-static void ufs_trunc_tindirect(struct inode *inode, unsigned *offsets)
+static void ufs_trunc_tindirect(struct inode *inode, unsigned *offsets, int depth2)
 {
         struct super_block *sb = inode->i_sb;
         struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
@@ -1190,7 +1190,7 @@ static void ufs_trunc_tindirect(struct inode *inode, unsigned *offsets)
         struct ufs_buffer_head * tind_bh;
         u64 tmp;
         void *tind, *p;
-        bool free_it = !offsets || !(offsets[0] || offsets[1] || offsets[2]);
+        bool free_it = !offsets || !depth2;
         unsigned tindirect_block = offsets ? *offsets++ : 0;
         unsigned i;
 
@@ -1207,7 +1207,7 @@ static void ufs_trunc_tindirect(struct inode *inode, unsigned *offsets)
 
         for (i = tindirect_block ; i < uspi->s_apb ; i++, offsets = NULL) {
                 tind = ubh_get_data_ptr(uspi, tind_bh, i);
-                ufs_trunc_dindirect(inode, offsets, tind);
+                ufs_trunc_dindirect(inode, offsets, depth2 - 1, tind);
                 ubh_mark_buffer_dirty(tind_bh);
         }
         if (free_it) {
@@ -1303,31 +1303,40 @@ static void __ufs_truncate_blocks(struct inode *inode)
         struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
         unsigned offsets[4];
         int depth = ufs_block_to_path(inode, DIRECT_BLOCK, offsets);
+        int depth2;
+
+        if (!depth)
+                return;
+
+        /* find the last non-zero in offsets[] */
+        for (depth2 = depth - 1; depth2; depth2--)
+                if (offsets[depth2])
+                        break;
 
         mutex_lock(&ufsi->truncate_mutex);
         switch (depth) {
         case 1:
                 ufs_trunc_direct(inode);
-                ufs_trunc_indirect(inode, NULL,
+                ufs_trunc_indirect(inode, NULL, 0,
                            ufs_get_direct_data_ptr(uspi, ufsi, UFS_IND_BLOCK));
-                ufs_trunc_dindirect(inode, NULL,
+                ufs_trunc_dindirect(inode, NULL, 0,
                             ufs_get_direct_data_ptr(uspi, ufsi, UFS_DIND_BLOCK));
-                ufs_trunc_tindirect(inode, NULL);
+                ufs_trunc_tindirect(inode, NULL, 0);
                 break;
         case 2:
-                ufs_trunc_indirect(inode, offsets + 1,
+                ufs_trunc_indirect(inode, offsets + 1, depth2,
                            ufs_get_direct_data_ptr(uspi, ufsi, UFS_IND_BLOCK));
-                ufs_trunc_dindirect(inode, NULL,
+                ufs_trunc_dindirect(inode, NULL, 0,
                             ufs_get_direct_data_ptr(uspi, ufsi, UFS_DIND_BLOCK));
-                ufs_trunc_tindirect(inode, NULL);
+                ufs_trunc_tindirect(inode, NULL, 0);
                 break;
         case 3:
-                ufs_trunc_dindirect(inode, offsets + 1,
+                ufs_trunc_dindirect(inode, offsets + 1, depth2,
                             ufs_get_direct_data_ptr(uspi, ufsi, UFS_DIND_BLOCK));
-                ufs_trunc_tindirect(inode, NULL);
+                ufs_trunc_tindirect(inode, NULL, 0);
                 break;
         case 4:
-                ufs_trunc_tindirect(inode, offsets + 1);
+                ufs_trunc_tindirect(inode, offsets + 1, depth2);
         }
         ufsi->i_lastfrag = DIRECT_FRAGMENT;
         mutex_unlock(&ufsi->truncate_mutex);