Re: [PATCH 2/3] ext4: WANR_ON when detect abnormal 'i_reserved_data_blocks'

From: yebin (H)
Date: Mon Nov 21 2022 - 06:19:26 EST




On 2022/11/21 17:47, Jan Kara wrote:
On Thu 17-11-22 09:42:45, Ye Bin wrote:
From: Ye Bin <yebin10@xxxxxxxxxx>

If 'i_reserved_data_blocks' is not cleared which mean something wrong
with code, so emit WARN_ON to capture this abnormal closer to the first
scene.

Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
---
fs/ext4/super.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 63ef74eb8091..30885a6fe18b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1385,11 +1385,14 @@ static void ext4_destroy_inode(struct inode *inode)
dump_stack();
}
- if (EXT4_I(inode)->i_reserved_data_blocks)
- ext4_msg(inode->i_sb, KERN_ERR,
- "Inode %lu (%p): i_reserved_data_blocks (%u) not cleared!",
- inode->i_ino, EXT4_I(inode),
- EXT4_I(inode)->i_reserved_data_blocks);
+ if (EXT4_I(inode)->i_reserved_data_blocks) {
+ ext4_warning(inode->i_sb, "Inode %lu (%p): "
+ "i_reserved_data_blocks (%u) not cleared!",
+ inode->i_ino, EXT4_I(inode),
+ EXT4_I(inode)->i_reserved_data_blocks);
+
+ WARN_ON(1);
+ }
Hum, so I'd think that if this happens, the free space accounting is likely
wrong so we might as well just force the filesystem to error mode with
ext4_error() to force fsck? I also gives a good chance to various test
systems to detect there is some problem so we don't need the WARN_ON then?
What do others think?

Honza
Thanks for your advice, use ext4_error() maybe is suitable and also testable.