linux-kernel - [PATCH] ext4: align max orphan file size with e2fsprogs limit

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Message-Id: <20251120134233.2994147-1-libaokun@huaweicloud.com>
Date: Thu, 20 Nov 2025 21:42:33 +0800
From: libaokun@...weicloud.com
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu,
	adilger.kernel@...ger.ca,
	jack@...e.cz,
	linux-kernel@...r.kernel.org,
	yi.zhang@...wei.com,
	yangerkun@...wei.com,
	libaokun1@...wei.com,
	libaokun@...weicloud.com
Subject: [PATCH] ext4: align max orphan file size with e2fsprogs limit

From: Baokun Li <libaokun1@...wei.com>

Kernel commit 0a6ce20c1564 ("ext4: verify orphan file size is not too big")
limits the maximum supported orphan file size to 8 << 20.

However, in e2fsprogs, the orphan file size is set to 32–512 filesystem
blocks when creating a filesystem.

With 64k block size, formatting an ext4 fs >32G gives an orphan file bigger
than the kernel allows, so mount prints an error and fails:

    EXT4-fs (vdb): orphan file too big: 8650752
    EXT4-fs (vdb): mount failed

To prevent this issue and allow previously created 64KB filesystems to
mount, we updates the maximum allowed orphan file size in the kernel to
512 filesystem blocks.

Fixes: 0a6ce20c1564 ("ext4: verify orphan file size is not too big")
Signed-off-by: Baokun Li <libaokun1@...wei.com>
---
 fs/ext4/orphan.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/orphan.c b/fs/ext4/orphan.c
index 82d5e7501455..fb57bba0d19d 100644
--- a/fs/ext4/orphan.c
+++ b/fs/ext4/orphan.c
@@ -8,6 +8,8 @@
 #include "ext4.h"
 #include "ext4_jbd2.h"
 
+#define EXT4_MAX_ORPHAN_FILE_BLOCKS 512
+
 static int ext4_orphan_file_add(handle_t *handle, struct inode *inode)
 {
 	int i, j, start;
@@ -588,7 +590,7 @@ int ext4_init_orphan_info(struct super_block *sb)
 	 * consuming absurd amounts of memory when pinning blocks of orphan
 	 * file in memory.
 	 */
-	if (inode->i_size > 8 << 20) {
+	if (inode->i_size > (EXT4_MAX_ORPHAN_FILE_BLOCKS << inode->i_blkbits)) {
 		ext4_msg(sb, KERN_ERR, "orphan file too big: %llu",
 			 (unsigned long long)inode->i_size);
 		ret = -EFSCORRUPTED;
-- 
2.46.1