ufs: beginning of __ufs_truncate_block() massage

Use ufs_block_to_path() to find the cutoff path in the block pointers' tree.
For now just use the information about the depth (to bypass the fully
preserved subtrees); subsequent commits will use the information about actual
path.

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

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 4367218..afb0f32 100644 (file)
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -1336,14 +1336,22 @@ static void __ufs_truncate_blocks(struct inode *inode)
        struct ufs_inode_info *ufsi = UFS_I(inode);
        struct super_block *sb = inode->i_sb;
        struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
+       unsigned offsets[4];
+       int depth = ufs_block_to_path(inode, DIRECT_BLOCK, offsets);
 
        mutex_lock(&ufsi->truncate_mutex);
-       ufs_trunc_direct(inode);
-       ufs_trunc_indirect(inode, UFS_IND_BLOCK,
+       switch (depth) {
+       case 1:
+               ufs_trunc_direct(inode);
+       case 2:
+               ufs_trunc_indirect(inode, UFS_IND_BLOCK,
                           ufs_get_direct_data_ptr(uspi, ufsi, UFS_IND_BLOCK));
-       ufs_trunc_dindirect(inode, UFS_IND_BLOCK + uspi->s_apb,
+       case 3:
+               ufs_trunc_dindirect(inode, UFS_IND_BLOCK + uspi->s_apb,
                            ufs_get_direct_data_ptr(uspi, ufsi, UFS_DIND_BLOCK));
-       ufs_trunc_tindirect(inode);
+       case 4:
+               ufs_trunc_tindirect(inode);
+       }
        ufsi->i_lastfrag = DIRECT_FRAGMENT;
        mutex_unlock(&ufsi->truncate_mutex);
 }