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
--- a/lib/ext2fs/extent.c
+++ b/lib/ext2fs/extent.c
@@ -709,9 +709,11 @@
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 @@
/* 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 @@
}
/* 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_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
--- a/lib/ext2fs/extent_dbg.ct
+++ b/lib/ext2fs/extent_dbg.ct
@@ -55,6 +55,9 @@
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;