Re: [PATCH] btrfs: remove dead assignment to dirid in btrfs_search_path_in_tree()

[Filipe Manana]

On Tue, Feb 17, 2026 at 10:18 AM Miquel Sabaté Solà <mssola@xxxxxxxxxx> wrote:
>
> Hello,
>
> Burenchev Evgenii @ 2026-02-16 16:16 GMT:
>
> > From ff2df73ba6483b0dc67b3ed89d2a43c49f1c2eb8 Mon Sep 17 00:00:00 2001
> > From: Evgenii Burenchev <eburenchev@xxxxxxxxxxxx>
> > Date: Mon, 16 Feb 2026 18:39:30 +0300
> > Subject: [PATCH] btrfs: remove dead assignment to dirid in
> >  btrfs_search_path_in_tree()
> >
> > After the introduction of btrfs_search_backwards(), the directory
> > traversal state in btrfs_search_path_in_tree() is fully maintained via
> > struct btrfs_key. The local variable 'dirid' is no longer used to control
> > the search and the assignment
> >
> >     dirid = key.objectid;
> >
> > has no observable effect and is dead code.
> >
> > Remove the unused assignment to avoid confusion and silence static
> > analysis warnings.
> >
> > No functional change.
> >
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> >
> > Signed-off-by: Evgenii Burenchev <eburenchev@xxxxxxxxxxxx>
> > ---
> >  fs/btrfs/ioctl.c | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> > index a6cc2d3b414c..292043b11207 100644
> > --- a/fs/btrfs/ioctl.c
> > +++ b/fs/btrfs/ioctl.c
> > @@ -1708,7 +1708,6 @@ static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
> >               btrfs_release_path(path);
> >               key.objectid = key.offset;
> >               key.offset = (u64)-1;
> > -             dirid = key.objectid;
> >       }
> >       memmove(name, ptr, total_len);
> >       name[total_len] = '\0';
>
> I would add a Fixes tag with the commit that made this assignment
> useless.

No. We add Fixes tags for patches we want to backport to stable
releases, things that fix a problem affecting users, like functional
bugs or performance regressions for example.
For cleanups, removing unnecessary code, we don't want a Fixes tag, as
that will trigger unnecessary backport overhead.

> As far as I can tell this is commit 98d377a0894e ("Btrfs: don't
> miss inode ref items in BTRFS_IOC_INO_LOOKUP"), which made the update
> inside of the loop of 'dirid' no longer needed. This way it's easier to
> track from where this was no longer needed and whether that's really the
> case.
>
> Other than that, and taking a quick look at this function, I can already
> tell that the 'ret' variable could be initialized to 0 in the beginning
> and make the last assignment to it (just before the "out" label) not
> needed. Hence, while we are at it, could you also remove that
> assignment?
>
> Cheers,
> Miquel