* [PATCH bpf-next 0/2] Support RENAME_EXCHANGE on bpffs
@ 2021-10-20 8:29 Lorenz Bauer
2021-10-20 8:29 ` [PATCH bpf-next 1/2] libfs: support RENAME_EXCHANGE in simple_rename() Lorenz Bauer
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Lorenz Bauer @ 2021-10-20 8:29 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
Cc: kernel-team, Lorenz Bauer, netdev, bpf
Add support for renameat2(RENAME_EXCHANGE) on bpffs. This is useful
for atomic upgrades of our sk_lookup control plane.
* Create a temporary directory on bpffs
* Migrate maps and pin them into temporary directory
* Load new sk_lookup BPF, attach it and pin the link into temp dir
* renameat2(temp dir, state dir, RENAME_EXCHANGE)
* rmdir temp dir
Due to the sk_lookup semantics this means we can never end up in a
situation where an upgrade breaks the existing control plane.
Lorenz Bauer (2):
libfs: support RENAME_EXCHANGE in simple_rename()
selftests: bpf: test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs
fs/libfs.c | 6 ++-
.../selftests/bpf/prog_tests/test_bpffs.c | 39 +++++++++++++++++++
2 files changed, 44 insertions(+), 1 deletion(-)
--
2.30.2
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH bpf-next 1/2] libfs: support RENAME_EXCHANGE in simple_rename()
2021-10-20 8:29 [PATCH bpf-next 0/2] Support RENAME_EXCHANGE on bpffs Lorenz Bauer
@ 2021-10-20 8:29 ` Lorenz Bauer
2021-10-20 8:29 ` [PATCH bpf-next 2/2] selftests: bpf: test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs Lorenz Bauer
2021-10-21 0:14 ` [PATCH bpf-next 0/2] Support RENAME_EXCHANGE " Alexei Starovoitov
2 siblings, 0 replies; 5+ messages in thread
From: Lorenz Bauer @ 2021-10-20 8:29 UTC (permalink / raw)
To: Alexander Viro, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
Cc: kernel-team, Lorenz Bauer, linux-fsdevel, linux-kernel, netdev, bpf
Allow atomic exchange via RENAME_EXCHANGE when using simple_rename.
This affects binderfs, ramfs, hubetlbfs and bpffs. There isn't much
to do except update the various *time fields.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
fs/libfs.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/libfs.c b/fs/libfs.c
index 51b4de3b3447..93c03d593749 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -455,9 +455,12 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
struct inode *inode = d_inode(old_dentry);
int they_are_dirs = d_is_dir(old_dentry);
- if (flags & ~RENAME_NOREPLACE)
+ if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;
+ if (flags & RENAME_EXCHANGE)
+ goto done;
+
if (!simple_empty(new_dentry))
return -ENOTEMPTY;
@@ -472,6 +475,7 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
inc_nlink(new_dir);
}
+done:
old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
--
2.30.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH bpf-next 2/2] selftests: bpf: test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs
2021-10-20 8:29 [PATCH bpf-next 0/2] Support RENAME_EXCHANGE on bpffs Lorenz Bauer
2021-10-20 8:29 ` [PATCH bpf-next 1/2] libfs: support RENAME_EXCHANGE in simple_rename() Lorenz Bauer
@ 2021-10-20 8:29 ` Lorenz Bauer
2021-10-20 21:43 ` Andrii Nakryiko
2021-10-21 0:14 ` [PATCH bpf-next 0/2] Support RENAME_EXCHANGE " Alexei Starovoitov
2 siblings, 1 reply; 5+ messages in thread
From: Lorenz Bauer @ 2021-10-20 8:29 UTC (permalink / raw)
To: Shuah Khan, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
Cc: kernel-team, Lorenz Bauer, linux-kselftest, netdev, bpf, linux-kernel
Add tests to exercise the behaviour of RENAME_EXCHANGE and RENAME_NOREPLACE
on bpffs. The former checks that after an exchange the inode of two
directories has changed. The latter checks that the source still exists
after a failed rename.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
.../selftests/bpf/prog_tests/test_bpffs.c | 39 +++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
index 172c999e523c..9c28ae9589bf 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#define _GNU_SOURCE
+#include <stdio.h>
#include <sched.h>
#include <sys/mount.h>
#include <sys/stat.h>
@@ -29,6 +30,7 @@ static int read_iter(char *file)
static int fn(void)
{
+ struct stat a, b;
int err, duration = 0;
err = unshare(CLONE_NEWNS);
@@ -67,6 +69,43 @@ static int fn(void)
err = read_iter(TDIR "/fs2/progs.debug");
if (CHECK(err, "reading " TDIR "/fs2/progs.debug", "failed\n"))
goto out;
+
+ err = mkdir(TDIR "/fs1/a", 0777);
+ if (CHECK(err, "creating " TDIR "/fs1/a", "failed\n"))
+ goto out;
+ err = mkdir(TDIR "/fs1/a/1", 0777);
+ if (CHECK(err, "creating " TDIR "/fs1/a/1", "failed\n"))
+ goto out;
+ err = mkdir(TDIR "/fs1/b", 0777);
+ if (CHECK(err, "creating " TDIR "/fs1/b", "failed\n"))
+ goto out;
+
+ /* Check that RENAME_EXCHANGE works. */
+ err = stat(TDIR "/fs1/a", &a);
+ if (CHECK(err, "stat(" TDIR "/fs1/a)", "failed\n"))
+ goto out;
+ err = renameat2(0, TDIR "/fs1/a", 0, TDIR "/fs1/b", RENAME_EXCHANGE);
+ if (CHECK(err, "renameat2(RENAME_EXCHANGE)", "failed\n"))
+ goto out;
+ err = stat(TDIR "/fs1/b", &b);
+ if (CHECK(err, "stat(" TDIR "/fs1/b)", "failed\n"))
+ goto out;
+ if (CHECK(a.st_ino != b.st_ino, "b should have a's inode", "failed\n"))
+ goto out;
+ err = access(TDIR "/fs1/b/1", F_OK);
+ if (CHECK(err, "access(" TDIR "/fs1/b/1)", "failed\n"))
+ goto out;
+
+ /* Check that RENAME_NOREPLACE works. */
+ err = renameat2(0, TDIR "/fs1/b", 0, TDIR "/fs1/a", RENAME_NOREPLACE);
+ if (CHECK(!err, "renameat2(RENAME_NOREPLACE)", "succeeded\n")) {
+ err = -EINVAL;
+ goto out;
+ }
+ err = access(TDIR "/fs1/b", F_OK);
+ if (CHECK(err, "access(" TDIR "/fs1/b)", "failed\n"))
+ goto out;
+
out:
umount(TDIR "/fs1");
umount(TDIR "/fs2");
--
2.30.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next 2/2] selftests: bpf: test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs
2021-10-20 8:29 ` [PATCH bpf-next 2/2] selftests: bpf: test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs Lorenz Bauer
@ 2021-10-20 21:43 ` Andrii Nakryiko
0 siblings, 0 replies; 5+ messages in thread
From: Andrii Nakryiko @ 2021-10-20 21:43 UTC (permalink / raw)
To: Lorenz Bauer
Cc: Shuah Khan, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
kernel-team, open list:KERNEL SELFTEST FRAMEWORK, Networking,
bpf, open list
On Wed, Oct 20, 2021 at 1:30 AM Lorenz Bauer <lmb@cloudflare.com> wrote:
>
> Add tests to exercise the behaviour of RENAME_EXCHANGE and RENAME_NOREPLACE
> on bpffs. The former checks that after an exchange the inode of two
> directories has changed. The latter checks that the source still exists
> after a failed rename.
>
> Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
> ---
> .../selftests/bpf/prog_tests/test_bpffs.c | 39 +++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
> index 172c999e523c..9c28ae9589bf 100644
> --- a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
> +++ b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0
> /* Copyright (c) 2020 Facebook */
> #define _GNU_SOURCE
> +#include <stdio.h>
> #include <sched.h>
> #include <sys/mount.h>
> #include <sys/stat.h>
> @@ -29,6 +30,7 @@ static int read_iter(char *file)
>
> static int fn(void)
> {
> + struct stat a, b;
> int err, duration = 0;
>
> err = unshare(CLONE_NEWNS);
> @@ -67,6 +69,43 @@ static int fn(void)
> err = read_iter(TDIR "/fs2/progs.debug");
> if (CHECK(err, "reading " TDIR "/fs2/progs.debug", "failed\n"))
> goto out;
> +
> + err = mkdir(TDIR "/fs1/a", 0777);
> + if (CHECK(err, "creating " TDIR "/fs1/a", "failed\n"))
> + goto out;
> + err = mkdir(TDIR "/fs1/a/1", 0777);
> + if (CHECK(err, "creating " TDIR "/fs1/a/1", "failed\n"))
> + goto out;
> + err = mkdir(TDIR "/fs1/b", 0777);
> + if (CHECK(err, "creating " TDIR "/fs1/b", "failed\n"))
> + goto out;
> +
> + /* Check that RENAME_EXCHANGE works. */
> + err = stat(TDIR "/fs1/a", &a);
> + if (CHECK(err, "stat(" TDIR "/fs1/a)", "failed\n"))
> + goto out;
> + err = renameat2(0, TDIR "/fs1/a", 0, TDIR "/fs1/b", RENAME_EXCHANGE);
> + if (CHECK(err, "renameat2(RENAME_EXCHANGE)", "failed\n"))
> + goto out;
> + err = stat(TDIR "/fs1/b", &b);
> + if (CHECK(err, "stat(" TDIR "/fs1/b)", "failed\n"))
> + goto out;
> + if (CHECK(a.st_ino != b.st_ino, "b should have a's inode", "failed\n"))
> + goto out;
> + err = access(TDIR "/fs1/b/1", F_OK);
> + if (CHECK(err, "access(" TDIR "/fs1/b/1)", "failed\n"))
> + goto out;
> +
> + /* Check that RENAME_NOREPLACE works. */
> + err = renameat2(0, TDIR "/fs1/b", 0, TDIR "/fs1/a", RENAME_NOREPLACE);
> + if (CHECK(!err, "renameat2(RENAME_NOREPLACE)", "succeeded\n")) {
> + err = -EINVAL;
> + goto out;
> + }
> + err = access(TDIR "/fs1/b", F_OK);
> + if (CHECK(err, "access(" TDIR "/fs1/b)", "failed\n"))
> + goto out;
> +
Please use ASSERT_xxx() for new code.
> out:
> umount(TDIR "/fs1");
> umount(TDIR "/fs2");
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next 0/2] Support RENAME_EXCHANGE on bpffs
2021-10-20 8:29 [PATCH bpf-next 0/2] Support RENAME_EXCHANGE on bpffs Lorenz Bauer
2021-10-20 8:29 ` [PATCH bpf-next 1/2] libfs: support RENAME_EXCHANGE in simple_rename() Lorenz Bauer
2021-10-20 8:29 ` [PATCH bpf-next 2/2] selftests: bpf: test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs Lorenz Bauer
@ 2021-10-21 0:14 ` Alexei Starovoitov
2 siblings, 0 replies; 5+ messages in thread
From: Alexei Starovoitov @ 2021-10-21 0:14 UTC (permalink / raw)
To: Lorenz Bauer
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
kernel-team, netdev, bpf
On Wed, Oct 20, 2021 at 09:29:54AM +0100, Lorenz Bauer wrote:
> Add support for renameat2(RENAME_EXCHANGE) on bpffs. This is useful
> for atomic upgrades of our sk_lookup control plane.
>
> * Create a temporary directory on bpffs
> * Migrate maps and pin them into temporary directory
> * Load new sk_lookup BPF, attach it and pin the link into temp dir
> * renameat2(temp dir, state dir, RENAME_EXCHANGE)
> * rmdir temp dir
>
> Due to the sk_lookup semantics this means we can never end up in a
> situation where an upgrade breaks the existing control plane.
That is a cool idea.
The selftest doesn't exercise all of this logic.
It's only testing that RENAME_EXCHANGE works on directories within bpffs.
Do we need a test for other types of paths?
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-10-21 0:14 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-10-20 8:29 [PATCH bpf-next 0/2] Support RENAME_EXCHANGE on bpffs Lorenz Bauer
2021-10-20 8:29 ` [PATCH bpf-next 1/2] libfs: support RENAME_EXCHANGE in simple_rename() Lorenz Bauer
2021-10-20 8:29 ` [PATCH bpf-next 2/2] selftests: bpf: test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs Lorenz Bauer
2021-10-20 21:43 ` Andrii Nakryiko
2021-10-21 0:14 ` [PATCH bpf-next 0/2] Support RENAME_EXCHANGE " Alexei Starovoitov
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