Re: [PATCH v1 1/9] ext2: fix ext2_xattr_delete_inode() context analysis warning

[Timothy Day]

On Tue, 14 Jul 2026 00:56:56 +0200, Marco Elver wrote:
> Relatively certain statement expressions were once again the problem -
> this should fix it: https://github.com/llvm/llvm-project/pull/209330
>
> I haven't had time to test the Clang fix on  fs/ext2/xattr.c with
> context analysis enabled  (please do so if you already build Clang
> yourself, otherwise I might get to it in ~week).

The fix wasn't enough. The commit message on patch 1/9 omitted another
warning. On vanilla Clang 23, I see:

linux/fs/ext2/xattr.c:829:6: error: rw_semaphore 'EXT2_I().xattr_sem' is \
  not held on every path through here [-Werror,-Wthread-safety-analysis]
  829 |         if (WARN_ON_ONCE(!down_write_trylock(&EXT2_I(inode)->xattr_sem)))
      |             ^

and:

linux/fs/ext2/xattr.c:860:2: error: releasing rw_semaphore \
  'EXT2_I().xattr_sem' that was not held [-Werror,-Wthread-safety-analysis]
  860 |         up_write(&EXT2_I(inode)->xattr_sem);
      |         ^

If I apply your patch, it resolves the second warning but not the first.
I tried to generate a fix [1]. That branch has both your patch and my
fix applied. Those two changes combined fix both warnings. My fix
tries to add some special casing for tracking contexts acquired by
trylocks. It works, but I'm not very confident on the correctness.

About next steps, it seems like everyone is happy with the rest of the
series. But the first patch should be dropped in favor of a fix to Clang.

Should I submit a v2 with 1/9 omitted? When would we be safe to merge
the series? Once the fix is merged to Clang? Is there some kind of
periodic LLVM release we ought to wait for?

Tim Day

[1] https://github.com/tim-day-387/llvm-project/commits/thread-safety-trylock-rebranch/