On Fri, Oct 09, 2020 at 02:28:19AM -0400, Dai Ngo wrote:
> NFS_FS=y as dependency of CONFIG_NFSD_V4_2_INTER_SSC still have
> build errors and some configs with NFSD=m to get NFS4ERR_STALE
> error when doing inter server copy.
>
> Added ops table in nfs_common for knfsd to access NFS client modules.
This looks like a good start, but I think it could be a lot simpler:
>
> Fixes: 3ac3711adb88 ("NFSD: Fix NFS server build errors")
> Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> ---
> changes from v2: fix 0-day build issues.
> ---
> fs/nfs/nfs4file.c | 40 +++++++++++--
> fs/nfs/nfs4super.c | 6 ++
> fs/nfs/super.c | 20 +++++++
> fs/nfs_common/Makefile | 1 +
> fs/nfs_common/nfs_ssc.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++
> fs/nfsd/Kconfig | 2 +-
> fs/nfsd/nfs4proc.c | 3 +-
> include/linux/nfs_ssc.h | 77 +++++++++++++++++++++++++
> 8 files changed, 289 insertions(+), 8 deletions(-)
> create mode 100644 fs/nfs_common/nfs_ssc.c
> create mode 100644 include/linux/nfs_ssc.h
>
> diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
> index fdfc77486ace..7d242fcb134a 100644
> --- a/fs/nfs/nfs4file.c
> +++ b/fs/nfs/nfs4file.c
> @@ -9,6 +9,7 @@
> #include <linux/falloc.h>
> #include <linux/mount.h>
> #include <linux/nfs_fs.h>
> +#include <linux/nfs_ssc.h>
> #include "delegation.h"
> #include "internal.h"
> #include "iostat.h"
> @@ -314,9 +315,8 @@ static loff_t nfs42_remap_file_range(struct file *src_file, loff_t src_off,
> static int read_name_gen = 1;
> #define SSC_READ_NAME_BODY "ssc_read_%d"
>
> -struct file *
> -nfs42_ssc_open(struct vfsmount *ss_mnt, struct nfs_fh *src_fh,
> - nfs4_stateid *stateid)
> +static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
> + struct nfs_fh *src_fh, nfs4_stateid *stateid)
> {
> struct nfs_fattr fattr;
> struct file *filep, *res;
> @@ -398,14 +398,42 @@ struct file *
> fput(filep);
> goto out_free_name;
> }
> -EXPORT_SYMBOL_GPL(nfs42_ssc_open);
> -void nfs42_ssc_close(struct file *filep)
> +
> +static void __nfs42_ssc_close(struct file *filep)
> {
> struct nfs_open_context *ctx = nfs_file_open_context(filep);
>
> ctx->state->flags = 0;
> }
> -EXPORT_SYMBOL_GPL(nfs42_ssc_close);
> +
> +static const struct nfs4_ssc_client_ops nfs4_ssc_clnt_ops_tbl = {
> + .sco_owner = THIS_MODULE,
> + .sco_open = __nfs42_ssc_open,
> + .sco_close = __nfs42_ssc_close,
> +};
> +
> +/**
> + * nfs42_ssc_register_ops - Wrapper to register NFS_V4 ops in nfs_common
> + *
> + * Return values:
> + * On success, returns 0
> + * %-EINVAL if validation check fails
> + */
> +int nfs42_ssc_register_ops(void)
> +{
> + return nfs42_ssc_register(&nfs4_ssc_clnt_ops_tbl);
> +}
> +
> +/**
> + * nfs42_ssc_unregister_ops - wrapper to un-register NFS_V4 ops in nfs_common
> + *
> + * Return values:
> + * None.
> + */
> +void nfs42_ssc_unregister_ops(void)
> +{
> + nfs42_ssc_unregister(&nfs4_ssc_clnt_ops_tbl);
> +}
> #endif /* CONFIG_NFS_V4_2 */
>
> const struct file_operations nfs4_file_operations = {
> diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c
> index 0c1ab846b83d..ed0c1f9fc890 100644
> --- a/fs/nfs/nfs4super.c
> +++ b/fs/nfs/nfs4super.c
> @@ -7,6 +7,7 @@
> #include <linux/mount.h>
> #include <linux/nfs4_mount.h>
> #include <linux/nfs_fs.h>
> +#include <linux/nfs_ssc.h>
> #include "delegation.h"
> #include "internal.h"
> #include "nfs4_fs.h"
> @@ -273,6 +274,10 @@ static int __init init_nfs_v4(void)
> err = nfs4_xattr_cache_init();
> if (err)
> goto out2;
> +
> + err = nfs42_ssc_register_ops();
> + if (err)
> + goto out2;
> #endif
>
> err = nfs4_register_sysctl();
> @@ -297,6 +302,7 @@ static void __exit exit_nfs_v4(void)
> unregister_nfs_version(&nfs_v4);
> #ifdef CONFIG_NFS_V4_2
> nfs4_xattr_cache_exit();
> + nfs42_ssc_unregister_ops();
> #endif
> nfs4_unregister_sysctl();
> nfs_idmap_quit();
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 7a70287f21a2..65636fef6a00 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -57,6 +57,7 @@
> #include <linux/rcupdate.h>
>
> #include <linux/uaccess.h>
> +#include <linux/nfs_ssc.h>
>
> #include "nfs4_fs.h"
> #include "callback.h"
> @@ -85,6 +86,11 @@
> };
> EXPORT_SYMBOL_GPL(nfs_sops);
>
> +static const struct nfs_ssc_client_ops nfs_ssc_clnt_ops_tbl = {
> + .sco_owner = THIS_MODULE,
> + .sco_sb_deactive = nfs_sb_deactive,
> +};
> +
> #if IS_ENABLED(CONFIG_NFS_V4)
> static int __init register_nfs4_fs(void)
> {
> @@ -106,6 +112,16 @@ static void unregister_nfs4_fs(void)
> }
> #endif
>
> +static int nfs_ssc_register_ops(void)
> +{
> + return nfs_ssc_register(&nfs_ssc_clnt_ops_tbl);
> +}
> +
> +static void nfs_ssc_unregister_ops(void)
> +{
> + nfs_ssc_unregister(&nfs_ssc_clnt_ops_tbl);
> +}
> +
> static struct shrinker acl_shrinker = {
> .count_objects = nfs_access_cache_count,
> .scan_objects = nfs_access_cache_scan,
> @@ -133,6 +149,9 @@ int __init register_nfs_fs(void)
> ret = register_shrinker(&acl_shrinker);
> if (ret < 0)
> goto error_3;
> + ret = nfs_ssc_register_ops();
> + if (ret < 0)
> + goto error_3;
> return 0;
> error_3:
> nfs_unregister_sysctl();
> @@ -152,6 +171,7 @@ void __exit unregister_nfs_fs(void)
> unregister_shrinker(&acl_shrinker);
> nfs_unregister_sysctl();
> unregister_nfs4_fs();
> + nfs_ssc_unregister_ops();
> unregister_filesystem(&nfs_fs_type);
> }
>
> diff --git a/fs/nfs_common/Makefile b/fs/nfs_common/Makefile
> index 4bebe834c009..fa82f5aaa6d9 100644
> --- a/fs/nfs_common/Makefile
> +++ b/fs/nfs_common/Makefile
> @@ -7,3 +7,4 @@ obj-$(CONFIG_NFS_ACL_SUPPORT) += nfs_acl.o
> nfs_acl-objs := nfsacl.o
>
> obj-$(CONFIG_GRACE_PERIOD) += grace.o
> +obj-$(CONFIG_GRACE_PERIOD) += nfs_ssc.o
> diff --git a/fs/nfs_common/nfs_ssc.c b/fs/nfs_common/nfs_ssc.c
> new file mode 100644
> index 000000000000..6d99a6d2d6b9
> --- /dev/null
> +++ b/fs/nfs_common/nfs_ssc.c
> @@ -0,0 +1,148 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * fs/nfs_common/nfs_ssc_comm.c
> + *
> + * Helper for knfsd's SSC to access ops in NFS client modules
> + *
> + * Author: Dai Ngo <dai.ngo@xxxxxxxxxx>
> + *
> + * Copyright (c) 2020, Oracle and/or its affiliates.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/fs.h>
> +#include <linux/nfs_ssc.h>
> +#include "../nfs/nfs4_fs.h"
> +
> +MODULE_LICENSE("GPL");
> +
> +/*
> + * NFS_FS
> + */
> +static void nfs_sb_deactive_def(struct super_block *sb);
> +
> +static struct nfs_ssc_client_ops nfs_ssc_clnt_ops_def = {
> + .sco_owner = THIS_MODULE,
> + .sco_sb_deactive = nfs_sb_deactive_def,
> +};
> +
> +/*
> + * NFS_V4
> + */
> +static struct file *nfs42_ssc_open_def(struct vfsmount *ss_mnt,
> + struct nfs_fh *src_fh, nfs4_stateid *stateid);
> +static void nfs42_ssc_close_def(struct file *filep);
> +
> +static struct nfs4_ssc_client_ops nfs4_ssc_clnt_ops_def = {
> + .sco_owner = THIS_MODULE,
> + .sco_open = nfs42_ssc_open_def,
> + .sco_close = nfs42_ssc_close_def,
> +};
> +
> +
> +struct nfs_ssc_client_ops_tbl nfs_ssc_client_tbl = {
> + .ssc_nfs4_ops = &nfs4_ssc_clnt_ops_def,
> + .ssc_nfs_ops = &nfs_ssc_clnt_ops_def
> +};
> +EXPORT_SYMBOL_GPL(nfs_ssc_client_tbl);
> +
> +
> +static struct file *nfs42_ssc_open_def(struct vfsmount *ss_mnt,
> + struct nfs_fh *src_fh, nfs4_stateid *stateid)
> +{
> + return ERR_PTR(-EIO);
> +}
> +
> +static void nfs42_ssc_close_def(struct file *filep)
> +{
> +}
I don't think we need any of these "_def" ops. We just shouldn't be
calling any of these ops in the case the operations aren't loaded.
> +
> +#ifdef CONFIG_NFS_V4_2
> +/**
> + * nfs42_ssc_register - install the NFS_V4 client ops in the nfs_ssc_client_tbl
> + * @ops: NFS_V4 ops to be installed
> + *
> + * Return values:
> + * On success, return 0
> + * %-EINVAL if validation check fails
> + */
> +int nfs42_ssc_register(const struct nfs4_ssc_client_ops *ops)
> +{
> + if (ops == NULL || ops->sco_open == NULL || ops->sco_close == NULL)
> + return -EINVAL;
This function only has one caller, and we know it won't do these things.
It's not worth the check and the error handling in the caller for
something so unlikely.
> + nfs_ssc_client_tbl.ssc_nfs4_ops = ops;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(nfs42_ssc_register);
> +
> +/**
> + * nfs42_ssc_unregister - uninstall the NFS_V4 client ops from
> + * the nfs_ssc_client_tbl
> + * @ops: ops to be uninstalled
> + *
> + * Return values:
> + * None
> + */
> +void nfs42_ssc_unregister(const struct nfs4_ssc_client_ops *ops)
> +{
> + if (nfs_ssc_client_tbl.ssc_nfs4_ops != ops)
> + return;
> +
> + nfs_ssc_client_tbl.ssc_nfs4_ops = &nfs4_ssc_clnt_ops_def;
> +}
> +EXPORT_SYMBOL_GPL(nfs42_ssc_unregister);
> +#endif /* CONFIG_NFS_V4_2 */
> +
> +/*
> + * NFS_FS
> + */
> +static void nfs_sb_deactive_def(struct super_block *sb)
> +{
> +}
> +
> +#ifdef CONFIG_NFS_V4_2
> +/**
> + * nfs_ssc_register - install the NFS_FS client ops in the nfs_ssc_client_tbl
> + * @ops: NFS_FS ops to be installed
> + *
> + * Return values:
> + * On success, return 0
> + * %-EINVAL if validation check fails
> + */
> +int nfs_ssc_register(const struct nfs_ssc_client_ops *ops)
> +{
> + if (ops == NULL || ops->sco_sb_deactive == NULL)
> + return -EINVAL;
Ditto, let's drop these checks.
> + nfs_ssc_client_tbl.ssc_nfs_ops = ops;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(nfs_ssc_register);
> +
> +/**
> + * nfs_ssc_unregister - uninstall the NFS_FS client ops from
> + * the nfs_ssc_client_tbl
> + * @ops: ops to be uninstalled
> + *
> + * Return values:
> + * None
> + */
> +void nfs_ssc_unregister(const struct nfs_ssc_client_ops *ops)
> +{
> + if (nfs_ssc_client_tbl.ssc_nfs_ops != ops)
> + return;
> + nfs_ssc_client_tbl.ssc_nfs_ops = &nfs_ssc_clnt_ops_def;
> +}
> +EXPORT_SYMBOL_GPL(nfs_ssc_unregister);
> +
> +#else
> +int nfs_ssc_register(const struct nfs_ssc_client_ops *ops)
> +{
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(nfs_ssc_register);
> +
> +void nfs_ssc_unregister(const struct nfs_ssc_client_ops *ops)
> +{
> +}
> +EXPORT_SYMBOL_GPL(nfs_ssc_unregister);
> +#endif /* CONFIG_NFS_V4_2 */
> diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
> index 99d2cae91bd6..f368f3215f88 100644
> --- a/fs/nfsd/Kconfig
> +++ b/fs/nfsd/Kconfig
> @@ -136,7 +136,7 @@ config NFSD_FLEXFILELAYOUT
>
> config NFSD_V4_2_INTER_SSC
> bool "NFSv4.2 inter server to server COPY"
> - depends on NFSD_V4 && NFS_V4_1 && NFS_V4_2 && NFS_FS=y
> + depends on NFSD_V4 && NFS_V4_1 && NFS_V4_2
> help
> This option enables support for NFSv4.2 inter server to
> server copy where the destination server calls the NFSv4.2
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index eaf50eafa935..84e10aef1417 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -38,6 +38,7 @@
> #include <linux/slab.h>
> #include <linux/kthread.h>
> #include <linux/sunrpc/addr.h>
> +#include <linux/nfs_ssc.h>
>
> #include "idmap.h"
> #include "cache.h"
> @@ -1247,7 +1248,7 @@ extern struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
> static void
> nfsd4_interssc_disconnect(struct vfsmount *ss_mnt)
> {
> - nfs_sb_deactive(ss_mnt->mnt_sb);
> + nfs_do_sb_deactive(ss_mnt->mnt_sb);
> mntput(ss_mnt);
> }
>
> diff --git a/include/linux/nfs_ssc.h b/include/linux/nfs_ssc.h
> new file mode 100644
> index 000000000000..45a763bd6b0b
> --- /dev/null
> +++ b/include/linux/nfs_ssc.h
> @@ -0,0 +1,77 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * include/linux/nfs_ssc.h
> + *
> + * Author: Dai Ngo <dai.ngo@xxxxxxxxxx>
> + *
> + * Copyright (c) 2020, Oracle and/or its affiliates.
> + */
> +
> +#include <linux/nfs_fs.h>
> +
> +extern struct nfs_ssc_client_ops_tbl nfs_ssc_client_tbl;
> +
> +/*
> + * NFS_V4
> + */
> +struct nfs4_ssc_client_ops {
> + struct module *sco_owner;
> + struct file *(*sco_open)(struct vfsmount *ss_mnt,
> + struct nfs_fh *src_fh, nfs4_stateid *stateid);
> + void (*sco_close)(struct file *filep);
> +};
> +
> +/*
> + * NFS_FS
> + */
> +struct nfs_ssc_client_ops {
> + struct module *sco_owner;
> + void (*sco_sb_deactive)(struct super_block *sb);
> +};
> +
> +struct nfs_ssc_client_ops_tbl {
> + const struct nfs4_ssc_client_ops *ssc_nfs4_ops;
> + const struct nfs_ssc_client_ops *ssc_nfs_ops;
> +};
> +
> +extern int nfs42_ssc_register_ops(void);
> +extern void nfs42_ssc_unregister_ops(void);
> +
> +extern int nfs42_ssc_register(const struct nfs4_ssc_client_ops *ops);
> +extern void nfs42_ssc_unregister(const struct nfs4_ssc_client_ops *ops);
> +
> +#ifdef CONFIG_NFSD_V4_2_INTER_SSC
> +static inline struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
> + struct nfs_fh *src_fh, nfs4_stateid *stateid)
> +{
> + struct file *file;
> +
> + if (!try_module_get(nfs_ssc_client_tbl.ssc_nfs4_ops->sco_owner))
> + return ERR_PTR(-EIO);
The module load already happened back when we did the get_fs_type in
nfsd4_interssc_connect(), and it's not going away at this point (or
there's something already terribly wrong with ss_mnt).
So I don't think we need any try_module_get()s or module_put()s.
--b.
> + file = (*nfs_ssc_client_tbl.ssc_nfs4_ops->sco_open)(ss_mnt, src_fh, stateid);
> + module_put(nfs_ssc_client_tbl.ssc_nfs4_ops->sco_owner);
> + return file;
> +}
> +
> +static inline void nfs42_ssc_close(struct file *filep)
> +{
> + if (!try_module_get(nfs_ssc_client_tbl.ssc_nfs4_ops->sco_owner))
> + return;
> + (*nfs_ssc_client_tbl.ssc_nfs4_ops->sco_close)(filep);
> + module_put(nfs_ssc_client_tbl.ssc_nfs4_ops->sco_owner);
> +}
> +#endif
> +
> +/*
> + * NFS_FS
> + */
> +extern int nfs_ssc_register(const struct nfs_ssc_client_ops *ops);
> +extern void nfs_ssc_unregister(const struct nfs_ssc_client_ops *ops);
> +
> +static inline void nfs_do_sb_deactive(struct super_block *sb)
> +{
> + if (!try_module_get(nfs_ssc_client_tbl.ssc_nfs_ops->sco_owner))
> + return;
> + (*nfs_ssc_client_tbl.ssc_nfs_ops->sco_sb_deactive)(sb);
> + module_put(nfs_ssc_client_tbl.ssc_nfs_ops->sco_owner);
> +}
> --
> 1.8.3.1
