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>

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 34d8dac4fe8b122fb98fac48263138feab26a670..e90266a221b8897521e2fb4ba5af55473877d256 100644 (file)
--- 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);