From 458939e5d9441448f87d3a6d45c84e041ee14786 Mon Sep 17 00:00:00 2001
From: Andreas Dilger <adilger@dilger.ca>
Date: Fri, 22 Jun 2018 18:08:54 -0400
Subject: [PATCH 2/2] e2fsck: set dir_nlink feature if large dir exists
commit 1a8015773a9316ee90f713c275fb3a38731735e4
If there is a directory with more than EXT2_LINK_MAX (65000)
subdirectories, but the DIR_NLINK feature is not set in the
superblock, the feature should be set before continuing on
to change the on-disk directory link count to 1.
While most filesystems should have DIR_NLINK set (it was set
by default for all ext4 filesystems, and all kernels between
2.6.23 and 4.12 automatically set it if the directory link
count grew too large), it is possible that this flag is lost
due to disk corruption or for an upgraded filesystem. We no
longer want kernels to automatically enable features.
Addresses: https://bugzilla.kernel.org/show_bug.cgi?id=196405
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
e2fsck/pass4.c | 14 +++++++++++++-
e2fsck/problem.c | 5 +++++
e2fsck/problem.h | 3 +++
3 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/e2fsck/pass4.c b/e2fsck/pass4.c
index 21d93f0c..ad95227c 100644
--- a/e2fsck/pass4.c
+++ b/e2fsck/pass4.c
@@ -98,6 +98,7 @@ void e2fsck_pass4(e2fsck_t ctx)
#endif
struct problem_context pctx;
__u16 link_count, link_counted;
+ int dir_nlink_fs;
char *buf = 0;
dgrp_t group, maxgroup;
@@ -112,6 +113,9 @@ void e2fsck_pass4(e2fsck_t ctx)
if (!(ctx->options & E2F_OPT_PREEN))
fix_problem(ctx, PR_4_PASS_HEADER, &pctx);
+ dir_nlink_fs = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_DIR_NLINK);
+
group = 0;
maxgroup = fs->group_desc_count;
if (ctx->progress)
@@ -158,8 +162,16 @@ void e2fsck_pass4(e2fsck_t ctx)
&link_counted);
}
isdir = ext2fs_test_inode_bitmap2(ctx->inode_dir_map, i);
- if (isdir && (link_counted > EXT2_LINK_MAX))
+ if (isdir && (link_counted > EXT2_LINK_MAX)) {
+ if (!dir_nlink_fs &&
+ fix_problem(ctx, PR_4_DIR_NLINK_FEATURE, &pctx)) {
+ fs->super->s_feature_ro_compat |=
+ EXT4_FEATURE_RO_COMPAT_DIR_NLINK;
+ ext2fs_mark_super_dirty(fs);
+ dir_nlink_fs = 1;
+ }
link_counted = 1;
+ }
if (link_counted != link_count) {
e2fsck_read_inode(ctx, i, inode, "pass4");
pctx.ino = i;
diff --git a/e2fsck/problem.c b/e2fsck/problem.c
index c3ba631b..0210ff8f 100644
--- a/e2fsck/problem.c
+++ b/e2fsck/problem.c
@@ -1576,6 +1576,11 @@ static struct e2fsck_problem problem_table[] = {
"They @s the same!\n"),
PROMPT_NONE, 0 },
+ /* directory exceeds max links, but no DIR_NLINK feature in superblock*/
+ { PR_4_DIR_NLINK_FEATURE,
+ N_("@d exceeds max links, but no DIR_NLINK feature in @S.\n"),
+ PROMPT_FIX, 0 },
+
/* Pass 5 errors */
/* Pass 5: Checking group summary information */
diff --git a/e2fsck/problem.h b/e2fsck/problem.h
index cf2df8ce..5712de59 100644
--- a/e2fsck/problem.h
+++ b/e2fsck/problem.h
@@ -1040,6 +1040,9 @@ struct problem_context {
/* Update quota information if it is inconsistent */
#define PR_6_UPDATE_QUOTAS 0x060002
+/* directory exceeds max links, but no DIR_NLINK feature in superblock */
+#define PR_4_DIR_NLINK_FEATURE 0x040006
+
/*
* Function declarations
*/
--
2.20.1