Re: [PATCH v3 0/3] cheaper MAY_EXEC handling for path lookup

Christian Brauner
2025-11-11T09:42:08Z

On Fri, 07 Nov 2025 15:21:46 +0100, Mateusz Guzik wrote:
> Commit message in patch 1 says it all.
>
> In short, MAY_WRITE checks are elided.
>
> This obsoletes the idea of pre-computing if perm checks are necessary as
> that turned out to be too hairy. The new code has 2 more branches per
> path component compared to that idea, but the perf difference for
> typical paths (< 6 components) was basically within noise. To be
> revisited if someone(tm) removes other slowdowns.
>
> [...]

Applied to the vfs-6.19.misc branch of the vfs/vfs.git tree.
Patches in the vfs-6.19.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.19.misc

[1/3] fs: speed up path lookup with cheaper handling of MAY_EXEC
https://git.kernel.org/vfs/vfs/c/5ecf656231cc
[2/3] btrfs: utilize IOP_FASTPERM_MAY_EXEC
https://git.kernel.org/vfs/vfs/c/d0231059c7f2
[3/3] fs: retire now stale MAY_WRITE predicts in inode_permission()