1From 79a7b5e1f387caf907ec88460cdb39b8364bfb0b Mon Sep 17 00:00:00 2001
2From: Theodore Ts'o <tytso@mit.edu>
3Date: Thu, 16 Mar 2023 22:57:10 -0400
4Subject: e2fsck: fix bad htree checksums in preen mode
5
6We attempt to fix directories which have a bad/corrupted htree index
7node by completely rebuilding the directory htree nodes.  Since this
8is a very safe thing to do and has no risk of losing directory
9entries, we've enabled this for preen mode.  Unfortunately, subsequent
10index nodes look like empty directory entries that fill the entire
11block --- without a checksum at the end of the directory.  So these
12nodes will be treated as a completely corrupted directory block, and
13this will *not* be fixed while in preen mode.
14
15So add code to treat an empty directory entry which covers the entire
16block as valid if the directory is already on the list of inodes to be
17rebuilt.
18
19Addresses-Gooogle-Bug: 178607853
20Signed-off-by: Theodore Ts'o <tytso@mit.edu>
21---
22 e2fsck/pass2.c | 16 ++++++++++++++--
23 1 file changed, 14 insertions(+), 2 deletions(-)
24
25diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
26index 287360943..2700e3409 100644
27--- a/e2fsck/pass2.c
28+++ b/e2fsck/pass2.c
29@@ -1341,7 +1341,18 @@ skip_checksum:
30 			    (rec_len < min_dir_len) ||
31 			    ((rec_len % 4) != 0) ||
32 			    ((ext2fs_dir_rec_len(ext2fs_dirent_name_len(dirent),
33-						 extended)) > rec_len)) {
34+						 extended)) > rec_len))
35+				problem = PR_2_DIR_CORRUPTED;
36+			if (problem) {
37+				if ((offset == 0) &&
38+				    (rec_len == fs->blocksize) &&
39+				    (dirent->inode == 0) &&
40+				    e2fsck_dir_will_be_rehashed(ctx, ino)) {
41+					problem = 0;
42+					max_block_size = fs->blocksize;
43+				}
44+			}
45+			if (problem) {
46 				if (fix_problem(ctx, PR_2_DIR_CORRUPTED,
47 						&cd->pctx)) {
48 #ifdef WORDS_BIGENDIAN
49@@ -1573,7 +1584,8 @@ skip_checksum:
50 		 */
51 		if (!(ctx->flags & E2F_FLAG_RESTART_LATER) &&
52 		    !(ext2fs_test_inode_bitmap2(ctx->inode_used_map,
53-						dirent->inode)))
54+						dirent->inode))
55+			)
56 			problem = PR_2_UNUSED_INODE;
57 
58 		if (problem) {
59-- 
60cgit 
61