+ ocfs2-validate-dr_fs_generation-of-dir-index-root-blocks.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: ocfs2: validate dr_fs_generation of dir index root blocks
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     ocfs2-validate-dr_fs_generation-of-dir-index-root-blocks.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-validate-dr_fs_generation-of-dir-index-root-blocks.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Joseph Qi <joseph.qi@linux.alibaba.com>
Subject: ocfs2: validate dr_fs_generation of dir index root blocks
Date: Sat, 5 Sep 2026 22:21:43 +0800

ocfs2_validate_dx_root() does not verify dr_fs_generation against the
superblock generation, unlike the extent and xattr block validators which
check h_fs_generation and xb_fs_generation respectively.  The field is
documented as "Must match super block".

Without the check, a stale dir index root block left on the device from
a previously formatted filesystem at the same physical block number can
pass validation as long as its signature, dr_blkno and checksum match.
Its index entries and suballocator information would then be used in
the new filesystem context.

Reject dir index root blocks whose dr_fs_generation does not match the
mounted filesystem, like the extent and xattr block validators do.

Link: https://lore.kernel.org/20260905142144.2869105-1-joseph.qi@linux.alibaba.com
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Heming Zhao <heming.zhao@suse.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ocfs2/dir.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/fs/ocfs2/dir.c~ocfs2-validate-dr_fs_generation-of-dir-index-root-blocks
+++ a/fs/ocfs2/dir.c
@@ -613,6 +613,14 @@ static int ocfs2_validate_dx_root(struct
 		goto bail;
 	}
 
+	if (le32_to_cpu(dx_root->dr_fs_generation) != OCFS2_SB(sb)->fs_generation) {
+		ret = ocfs2_error(sb,
+				  "Dir Index Root # %llu has an invalid dr_fs_generation of #%u\n",
+				  (unsigned long long)bh->b_blocknr,
+				  le32_to_cpu(dx_root->dr_fs_generation));
+		goto bail;
+	}
+
 	/*
 	 * Dir index root blocks are allocated from a per-slot suballocator,
 	 * so the slot must be in range.  Otherwise removing the index passes
_

Patches currently in -mm which might be from joseph.qi@linux.alibaba.com are

ocfs2-make-ocfs2_calc_xattr_init-return-void.patch
ocfs2-fix-deadlock-in-inline-data-truncate-transactions.patch
ocfs2-exit-recovery-thread-on-mount-error-path.patch
ocfs2-free-replay-slots-in-ocfs2_recovery_exit.patch
ocfs2-defer-suballocator-block-group-reclaim-to-workqueue.patch
ocfs2-restrict-ocfs2_invalid_slot-suballoc-slot-to-system-inodes.patch
ocfs2-validate-suballoc-bit-during-inode-read.patch
ocfs2-validate-suballoc-slot-and-bit-of-xattr-and-dir-index-blocks.patch
ocfs2-validate-suballoc-slot-and-bit-of-extent-and-refcount-blocks.patch
ocfs2-allow-xattr-bucket-entries-to-span-multiple-blocks.patch
ocfs2-reject-inconsistent-xattr-bucket-during-defrag.patch
ocfs2-skip-uninitialized-lockres-in-ocfs2_mark_lockres_freeing.patch
ocfs2-validate-dr_fs_generation-of-dir-index-root-blocks.patch
ocfs2-validate-dl_blkno-and-dl_fs_generation-of-dir-index-leaf-blocks.patch