The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9392a27d88b9707145d713654eb26f0c29789e50 Mon Sep 17 00:00:00 2001

From: Jens Axboe axboe@kernel.dk Date: Thu, 6 Feb 2020 21:42:51 -0700 Subject: [PATCH] io-wq: add support for inheriting ->fs

Some work items need this for relative path lookup, make it available like the other inherited credentials/mm/etc.

Cc: stable@vger.kernel.org # 5.3+ Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/fs/io-wq.c b/fs/io-wq.c index cb60a42b9fdf..7ac4a8876a50 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -16,6 +16,7 @@ #include <linux/slab.h> #include <linux/kthread.h> #include <linux/rculist_nulls.h> +#include <linux/fs_struct.h>

#include "io-wq.h"

@@ -59,6 +60,7 @@ struct io_worker { const struct cred *cur_creds; const struct cred *saved_creds; struct files_struct *restore_files; + struct fs_struct *restore_fs; };

#if BITS_PER_LONG == 64 @@ -151,6 +153,9 @@ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker) task_unlock(current); }

+ if (current->fs != worker->restore_fs) + current->fs = worker->restore_fs; + /* * If we have an active mm, we need to drop the wq lock before unusing * it. If we do, return true and let the caller retry the idle loop. @@ -311,6 +316,7 @@ static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker)

worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING); worker->restore_files = current->files; + worker->restore_fs = current->fs; io_wqe_inc_running(wqe, worker); }

@@ -481,6 +487,8 @@ static void io_worker_handle_work(struct io_worker *worker) current->files = work->files; task_unlock(current); } + if (work->fs && current->fs != work->fs) + current->fs = work->fs; if (work->mm != worker->mm) io_wq_switch_mm(worker, work); if (worker->cur_creds != work->creds) diff --git a/fs/io-wq.h b/fs/io-wq.h index 50b3378febf2..f152ba677d8f 100644 --- a/fs/io-wq.h +++ b/fs/io-wq.h @@ -74,6 +74,7 @@ struct io_wq_work { struct files_struct *files; struct mm_struct *mm; const struct cred *creds; + struct fs_struct *fs; unsigned flags; };

@@ -81,10 +82,11 @@ struct io_wq_work { do { \ (work)->list.next = NULL; \ (work)->func = _func; \ - (work)->flags = 0; \ (work)->files = NULL; \ (work)->mm = NULL; \ (work)->creds = NULL; \ + (work)->fs = NULL; \ + (work)->flags = 0; \ } while (0) \

typedef void (get_work_fn)(struct io_wq_work *);