Re: [PATCH 5.10 2/5] kernfs: use VFS negative dentry caching

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
ℹ️ This is part 2/5 of a series
⚠️ Found follow-up fixes in mainline

The upstream commit SHA1 provided is correct: c7e7c04274b13f98f758fb69b03f2ab61976ea80

WARNING: Author mismatch between patch and upstream commit:
Backport author: Qingfang Deng<dqfext@gmail.com>
Commit author: Ian Kent<raven@themaw.net>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (exact SHA1)
6.1.y | Present (exact SHA1)
5.15.y | Present (exact SHA1)

Found fixes commits:
410d591a1954 kernfs: don't create a negative dentry if inactive node exists
df38d852c681 kernfs: also call kernfs_set_rev() for positive dentry

Note: The patch differs from the upstream commit:
---
1:  c7e7c04274b13 ! 1:  6ca146f13dc9d kernfs: use VFS negative dentry caching
    @@ Metadata
      ## Commit message ##
         kernfs: use VFS negative dentry caching
     
    +    Commit c7e7c04274b13f98f758fb69b03f2ab61976ea80 upstream.
    +
         If there are many lookups for non-existent paths these negative lookups
         can lead to a lot of overhead during path walks.
     
---

NOTE: These results are for this patch alone. Full series testing will be
performed when all parts are received.

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.15.y       |  Success    |  Success   |