libext2fs: ext2fs_extents_fix_parents() should not modify the handle location

Previously, ext2fs_extent_fix_parents() would only avoid modifying the
cursor location associated with the extent handle the cursor was
pointed at a leaf node in the extent tree.  This is because it saved
the starting logical block number of the current extent, but not the
"level" of the extent (where level 0 is the leaf node, level 1 is the
interior node which points at blocks containing leaf nodes, etc.)

Fix ext2fs_extent_fix_parents() so it is guaranteed to not change the
current extent in the handle even if the current extent is not at the
bottom of the tree.

Also add a fix_extent command to the tst_extents program to make it
easier to test this function.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c
index 95a0a86..c6716bc 100644 (file)
--- a/lib/ext2fs/extent.c
+++ b/lib/ext2fs/extent.c
@@ -709,9 +709,11 @@ errcode_t ext2fs_extent_goto(ext2_extent_handle_t handle,
 errcode_t ext2fs_extent_fix_parents(ext2_extent_handle_t handle)
 {
        int                             retval = 0;
+       int                             orig_height;
        blk64_t                         start;
        struct extent_path              *path;
        struct ext2fs_extent            extent;
+       struct ext2_extent_info         info;
 
        EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
 
@@ -732,6 +734,10 @@ errcode_t ext2fs_extent_fix_parents(ext2_extent_handle_t handle)
        /* modified node's start block */
        start = extent.e_lblk;
 
+       if ((retval = ext2fs_extent_get_info(handle, &info)))
+               return retval;
+       orig_height = info.max_depth - info.curr_level;
+
        /* traverse up until index not first, or startblk matches, or top */
        while (handle->level > 0 &&
               (path->left == path->entries - 1)) {
@@ -750,7 +756,7 @@ errcode_t ext2fs_extent_fix_parents(ext2_extent_handle_t handle)
        }
 
        /* put handle back to where we started */
-       retval = ext2fs_extent_goto(handle, start);
+       retval = extent_goto(handle, orig_height, start);
 done:
        return retval;
 }
@@ -1943,6 +1949,23 @@ void do_print_all(int argc, char **argv)
        }
 }
 
+void do_fix_parents(int argc, char **argv)
+{
+       struct ext2fs_extent    extent;
+       struct ext2_extent_info info;
+       errcode_t               retval;
+
+       if (common_extent_args_process(argc, argv, 1, 1, "fix_parents", "",
+                                      CHECK_FS_RW))
+               return;
+
+       retval = ext2fs_extent_fix_parents(current_handle);
+       if (retval) {
+               com_err(argv[0], retval, 0);
+               return;
+       }
+}
+
 void do_info(int argc, char **argv)
 {
        struct ext2fs_extent    extent;

diff --git a/lib/ext2fs/extent_dbg.ct b/lib/ext2fs/extent_dbg.ct
index d0571f4..c1d8033 100644 (file)
--- a/lib/ext2fs/extent_dbg.ct
+++ b/lib/ext2fs/extent_dbg.ct
@@ -55,6 +55,9 @@ request do_insert_node, "Insert node",
 request do_split_node, "Split node",
        split_node, split;
 
+request do_fix_parents, "Fix parents",
+       fix_parents, fixp;
+
 request do_set_bmap, "Set block mapping",
        set_bmap;