From: Eric Sandeen <sandeen@redhat.com>
Date: Tue, 8 Apr 2008 03:00:59 +0000 (-0500)
Subject: Make extent_goto() deterministic when logical block not found
X-Git-Tag: v1.41-WIP-0427~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c21ed7705be908a5697095e597849804302edd21;p=thirdparty%2Fe2fsprogs.git

Make extent_goto() deterministic when logical block not found

Make sure that extent_goto() leaves us at the last extent
prior to the requested logical block, if the logical block
requested lands in a hole.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c
index 9f19e7b61..e7b7e8556 100644
--- a/lib/ext2fs/extent.c
+++ b/lib/ext2fs/extent.c
@@ -553,6 +553,12 @@ errcode_t ext2fs_extent_free_path(ext2_extent_path_t path)
 }
 #endif
 
+/*
+ * Go to the node at leaf_level which contains logical block blk.
+ *
+ * If "blk" has no mapping (hole) then handle is left at last
+ * extent before blk.
+ */
 static errcode_t extent_goto(ext2_extent_handle_t handle,
 			     int leaf_level, blk64_t blk)
 {
@@ -566,11 +572,16 @@ static errcode_t extent_goto(ext2_extent_handle_t handle,
 	dbg_print_extent("root", &extent);
 	while (1) {
 		if (handle->level - leaf_level == handle->max_depth) {
+			/* block is in this &extent */
 			if ((blk >= extent.e_lblk) &&
 			    (blk < extent.e_lblk + extent.e_len))
 				return 0;
-			if (blk < extent.e_lblk)
+			if (blk < extent.e_lblk) {
+				retval = ext2fs_extent_get(handle,
+							   EXT2_EXTENT_PREV_SIB,
+							   &extent);
 				return EXT2_ET_EXTENT_NOT_FOUND;
+			}
 			retval = ext2fs_extent_get(handle,
 						   EXT2_EXTENT_NEXT_SIB,
 						   &extent);