linux-ext4 - [PATCH] ext4: skip inode expansion on readonly filesystems

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Message-ID: <20250923050202.1078052-1-kartikey406@gmail.com>
Date: Tue, 23 Sep 2025 10:32:02 +0530
From: Deepanshu Kartikey <kartikey406@...il.com>
To: syzbot+4c9d23743a2409b80293@...kaller.appspotmail.com
Cc: linux-ext4@...r.kernel.org,
	Deepanshu Kartikey <kartikey406@...il.com>
Subject: [PATCH] ext4: skip inode expansion on  readonly filesystems

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


Fix WARNING in ext4_xattr_block_set() during orphan cleanup on readonly
filesystems when debug_want_extra_isize mount option is used.
The issue occurs when ext4_try_to_expand_extra_isize() attempts to modify
inodes on readonly filesystems during orphan cleanup, leading to warnings
when encountering invalid xattr entries. Add a readonly check to skip
expansion in this case.

Reported-by: syzbot+4c9d23743a2409b80293@...kaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=4c9d23743a2409b80293
Signed-off-by: Deepanshu Kartikey <kartikey406@...il.com>
---
 fs/ext4/inode.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5b7a15db4953..ff51a4567c4f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -6345,7 +6345,8 @@ static int __ext4_expand_extra_isize(struct inode *inode,
 	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
 	struct ext4_inode_info *ei = EXT4_I(inode);
 	int error;
-
+	if (sb_rdonly(inode->i_sb))
+		return 0;
 	/* this was checked at iget time, but double check for good measure */
 	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
 	    (ei->i_extra_isize & 3)) {
@@ -6403,6 +6404,8 @@ static int ext4_try_to_expand_extra_isize(struct inode *inode,
 					  struct ext4_iloc iloc,
 					  handle_t *handle)
 {
+	if (sb_rdonly(inode->i_sb))
+		return 0;
 	int no_expand;
 	int error;
 
-- 
2.43.0