ufs_trunc_branch(): kill recursion

turn recursion into a pair of loops

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

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index dac81c318da71f4ca590f42d5a6990e67d72aa59..314caad56d8357f61dc8a391bc493d3f6351c6c6 100644 (file)
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -1124,34 +1124,14 @@ static void free_full_branch(struct inode *inode, int depth, void *p)
        mark_inode_dirty(inode);
 }
 
-static void ufs_trunc_branch(struct inode *inode, unsigned *offsets, int depth2, int depth, void *p)
+static void free_branch_tail(struct inode *inode, unsigned from, struct ufs_buffer_head *ubh, int depth)
 {
        struct super_block *sb = inode->i_sb;
        struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
-       struct ufs_inode_info *ufsi = UFS_I(inode);
-       struct ufs_buffer_head *ubh;
-       u64 tmp;
-       unsigned from = *offsets++;
        unsigned i;
 
-       tmp = ufs_data_ptr_to_cpu(sb, p);
-       if (!tmp)
-               return;
-       ubh = ubh_bread (sb, tmp, uspi->s_bsize);
-       if (!ubh) {
-               write_seqlock(&ufsi->meta_lock);
-               ufs_data_ptr_clear(uspi, p);
-               write_sequnlock(&ufsi->meta_lock);
-               return;
-       }
-
-       if (--depth2) {
-               void *ind = ubh_get_data_ptr(uspi, ubh, from++);
-               ufs_trunc_branch(inode, offsets, depth2, depth - 1, ind);
-               ubh_mark_buffer_dirty(ubh);
-       }
        if (--depth) {
-               for (i = from ; i < uspi->s_apb ; i++) {
+               for (i = from; i < uspi->s_apb ; i++) {
                        void *ind = ubh_get_data_ptr(uspi, ubh, i);
                        free_full_branch(inode, depth, ind);
                        ubh_mark_buffer_dirty(ubh);
@@ -1161,7 +1141,7 @@ static void ufs_trunc_branch(struct inode *inode, unsigned *offsets, int depth2,
 
                for (i = from; i < uspi->s_apb; i++) {
                        void *ind = ubh_get_data_ptr(uspi, ubh, i);
-                       tmp = ufs_data_ptr_to_cpu(sb, ind);
+                       u64 tmp = ufs_data_ptr_to_cpu(sb, ind);
                        if (!tmp)
                                continue;
 
@@ -1258,6 +1238,9 @@ static void __ufs_truncate_blocks(struct inode *inode)
        int depth = ufs_block_to_path(inode, DIRECT_BLOCK, offsets);
        int depth2;
        unsigned i;
+       struct ufs_buffer_head *ubh[3];
+       void *p;
+       u64 block;
 
        if (!depth)
                return;
@@ -1272,9 +1255,26 @@ static void __ufs_truncate_blocks(struct inode *inode)
                ufs_trunc_direct(inode);
                offsets[0] = UFS_IND_BLOCK;
        } else {
-               if (depth2)
-                       ufs_trunc_branch(inode, offsets + 1, depth2, depth - 1,
-                          ufs_get_direct_data_ptr(uspi, ufsi, offsets[0]++));
+               /* get the blocks that should be partially emptied */
+               p = ufs_get_direct_data_ptr(uspi, ufsi, offsets[0]);
+               for (i = 0; i < depth2; i++) {
+                       offsets[i]++;   /* next branch is fully freed */
+                       block = ufs_data_ptr_to_cpu(sb, p);
+                       if (!block)
+                               break;
+                       ubh[i] = ubh_bread(sb, block, uspi->s_bsize);
+                       if (!ubh[i]) {
+                               write_seqlock(&ufsi->meta_lock);
+                               ufs_data_ptr_clear(uspi, p);
+                               write_sequnlock(&ufsi->meta_lock);
+                               break;
+                       }
+                       p = ubh_get_data_ptr(uspi, ubh[i], offsets[i + 1]);
+               }
+               while (i--) {
+                       ubh_mark_buffer_dirty(ubh[i]);
+                       free_branch_tail(inode, offsets[i + 1], ubh[i], depth - i - 1);
+               }
        }
        for (i = offsets[0]; i <= UFS_TIND_BLOCK; i++) {
                free_full_branch(inode, i - UFS_IND_BLOCK + 1,