linux-ext4 - [PATCH -next] ext2: fix fs corruption when trying to remove a non-empty directory with IO error

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Message-ID: <20220615090010.1544152-1-yebin10@huawei.com>
Date:   Wed, 15 Jun 2022 17:00:10 +0800
From:   Ye Bin <yebin10@...wei.com>
To:     <jack@...e.cz>, <linux-ext4@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, Ye Bin <yebin10@...wei.com>
Subject: [PATCH -next] ext2: fix fs corruption when trying to remove a non-empty directory with IO error

We got issue as follows:
[home]# mount  /dev/sdd  test
[home]# cd test
[test]# ls
dir1  lost+found
[test]# rmdir  dir1
ext2_empty_dir: inject fault
[test]# ls
lost+found
[test]# cd ..
[home]# umount test
[home]# fsck.ext2 -fn  /dev/sdd
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Inode 4065, i_size is 0, should be 1024.  Fix? no

Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Unconnected directory inode 4065 (/???)
Connect to /lost+found? no

'..' in ... (4065) is / (2), should be <The NULL inode> (0).
Fix? no

Pass 4: Checking reference counts
Inode 2 ref count is 3, should be 4.  Fix? no

Inode 4065 ref count is 2, should be 3.  Fix? no

Pass 5: Checking group summary information

/dev/sdd: ********** WARNING: Filesystem still has errors **********

/dev/sdd: 14/128016 files (0.0% non-contiguous), 18477/512000 blocks

Reason is same with commit 7aab5c84a0f6. We can't assume directory
is empty when read directory entry failed.

Signed-off-by: Ye Bin <yebin10@...wei.com>
---
 fs/ext2/dir.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 3bd5772b401b..8f597753ac12 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -672,17 +672,14 @@ int ext2_empty_dir (struct inode * inode)
 	void *page_addr = NULL;
 	struct page *page = NULL;
 	unsigned long i, npages = dir_pages(inode);
-	int dir_has_error = 0;

 	for (i = 0; i < npages; i++) {
 		char *kaddr;
 		ext2_dirent * de;
-		page = ext2_get_page(inode, i, dir_has_error, &page_addr);
+		page = ext2_get_page(inode, i, 0, &page_addr);

-		if (IS_ERR(page)) {
-			dir_has_error = 1;
-			continue;
-		}
+		if (IS_ERR(page))
+			goto not_empty;

 		kaddr = page_addr;
 		de = (ext2_dirent *)kaddr;
-- 
2.31.1