Re: [PATCH 0/3] show orphan file inode detail info

["Theodore Tso" <tytso@mit.edu>]

On Fri, Apr 03, 2026 at 04:25:04PM +0800, Ye Bin wrote:
> From: Ye Bin <yebin10@huawei.com>
> 
> In actual production environments, the issue of inconsistency between
> df and du is frequently encountered. In many cases, the cause of the
> problem can be identified through the use of lsof. However, when
> overlayfs is combined with project quota configuration, the issue becomes
> more complex and troublesome to diagnose. First, to determine the project
> ID, one needs to obtain orphaned nodes using `fsck.ext4 -fn /dev/xx`, and
> then retrieve file information through `debugfs`. However, the file names
> cannot always be obtained, and it is often unclear which files they are.
> To identify which files these are, one would need to use crash for online
> debugging or use kprobe to gather information incrementally. However, some
> customers in production environments do not agree to upload any tools, and
> online debugging might impact the business. There are also scenarios where
> files are opened in kernel mode, which do not generate file descriptors(fds),
> making it impossible to identify which files were deleted but still have
> references through lsof. This patchset adds a procfs interface to query
> information about orphaned nodes, which can assist in the analysis and
> localization of such issues.

There are some concens which were noted by Sashiko review, including
races with unmountings, a potential deadlock, and some issues relating
to long pathnames, and a TOCTOU race that might lead to a file system
erroneously being declared corrupted.  PTAL:

https://sashiko.dev/#/patchset/20260403082507.1882703-1-yebin%40huaweicloud.com

Thanks!

						- Ted