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Thu, 05 Mar 2026 23:26:48 -0800 (PST) From: Askar Safin To: brauner@kernel.org Cc: axboe@kernel.dk, jack@suse.cz, jannh@google.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, tj@kernel.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Subject: Re: [PATCH RFC DRAFT POC 00/11] fs,kthread: isolate all kthreads in nullfs Date: Fri, 6 Mar 2026 10:26:39 +0300 Message-ID: <20260306072639.1731059-1-safinaskar@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260303-work-kthread-nullfs-v1-0-87e559b94375@kernel.org> References: <20260303-work-kthread-nullfs-v1-0-87e559b94375@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Christian Brauner : > Instead of sharing fs_struct between kernel threads and pid 1 we give > pid a separate userspace_init_fs struct. You meant "we give pid 1 a separate" > The only remaining kernel tasks that actually share init's filesystem > state are usermodhelpers This sounds like usermodhelpers actually *share* init's fs_struct. This is false, otherwise usermodhelpers could just do "chdir" and change cwd of pid 1. So, please, rephrase this sentence. > Be aggressive about this: We simply reject operating on stale > fs_struct state by reverting userspace_init_fs to nullfs. I think in this case unshare should simply fail and return error to userspace. > PID 1 uses pid1_fs which points to the initramfs You meant userspace_init_fs, not pid1_fs. (pid1_fs is mentioned two times in cover letter. Also in comments in patch 06/11.) > `init_chroot_to_overmount()` at the start of `kernel_init()`) There is no function named "init_chroot_to_overmount". I hope you are not offended. I just did some proof-reading. -- Askar Safin