[PATCH 23/24] afs: Implement namespacing [ver #7]

From: David Howells
Date: Thu Apr 19 2018 - 09:34:01 EST

Implement namespacing within AFS, but don't yet let mounts occur outside
the init namespace. An additional patch will be required propagate the
network namespace across automounts.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

fs/afs/cell.c | 4 +-
fs/afs/internal.h | 36 ++++++++++++---------
fs/afs/main.c | 33 ++++++++++++++++----
fs/afs/proc.c | 89 +++++++++++++++++++++++++++++++++++------------------
fs/afs/super.c | 58 +++++++++++++++++++++++++----------
5 files changed, 149 insertions(+), 71 deletions(-)

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index fdf4c36cff79..a98a8a3d5544 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -528,7 +528,7 @@ static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
NULL, 0,
cell, 0, true);
#endif
- ret = afs_proc_cell_setup(net, cell);
+ ret = afs_proc_cell_setup(cell);
if (ret < 0)
return ret;
spin_lock(&net->proc_cells_lock);
@@ -544,7 +544,7 @@ static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
{
_enter("%s", cell->name);

- afs_proc_cell_remove(net, cell);
+ afs_proc_cell_remove(cell);

spin_lock(&net->proc_cells_lock);
list_del_init(&cell->proc_link);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 0266730b3ad7..a5161c0ae3ab 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -22,6 +22,8 @@
#include <linux/backing-dev.h>
#include <linux/uuid.h>
#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/sock.h>
#include <net/af_rxrpc.h>

#include "afs.h"
@@ -192,7 +194,7 @@ struct afs_read {
* - there's one superblock per volume
*/
struct afs_super_info {
- struct afs_net *net; /* Network namespace */
+ struct net *net_ns; /* Network namespace */
struct afs_cell *cell; /* The cell in which the volume resides */
struct afs_volume *volume; /* volume record */
bool dyn_root; /* True if dynamic root */
@@ -221,6 +223,7 @@ struct afs_sysnames {
* AFS network namespace record.
*/
struct afs_net {
+ struct net *net; /* Backpointer to the owning net namespace */
struct afs_uuid uuid;
bool live; /* F if this namespace is being removed */

@@ -283,7 +286,6 @@ struct afs_net {
};

extern const char afs_init_sysname[];
-extern struct afs_net __afs_net;// Dummy AFS network namespace; TODO: replace with real netns

enum afs_cell_state {
AFS_CELL_UNSET,
@@ -790,34 +792,36 @@ extern int afs_drop_inode(struct inode *);
* main.c
*/
extern struct workqueue_struct *afs_wq;
+extern int afs_net_id;

-static inline struct afs_net *afs_d2net(struct dentry *dentry)
+static inline struct afs_net *afs_net(struct net *net)
{
- return &__afs_net;
+ return net_generic(net, afs_net_id);
}

-static inline struct afs_net *afs_i2net(struct inode *inode)
+static inline struct afs_net *afs_sb2net(struct super_block *sb)
{
- return &__afs_net;
+ return afs_net(AFS_FS_S(sb)->net_ns);
}

-static inline struct afs_net *afs_v2net(struct afs_vnode *vnode)
+static inline struct afs_net *afs_d2net(struct dentry *dentry)
{
- return &__afs_net;
+ return afs_sb2net(dentry->d_sb);
}

-static inline struct afs_net *afs_sock2net(struct sock *sk)
+static inline struct afs_net *afs_i2net(struct inode *inode)
{
- return &__afs_net;
+ return afs_sb2net(inode->i_sb);
}

-static inline struct afs_net *afs_get_net(struct afs_net *net)
+static inline struct afs_net *afs_v2net(struct afs_vnode *vnode)
{
- return net;
+ return afs_i2net(&vnode->vfs_inode);
}

-static inline void afs_put_net(struct afs_net *net)
+static inline struct afs_net *afs_sock2net(struct sock *sk)
{
+ return net_generic(sock_net(sk), afs_net_id);
}

static inline void __afs_stat(atomic_t *s)
@@ -852,8 +856,8 @@ extern int afs_get_ipv4_interfaces(struct afs_interface *, size_t, bool);
*/
extern int __net_init afs_proc_init(struct afs_net *);
extern void __net_exit afs_proc_cleanup(struct afs_net *);
-extern int afs_proc_cell_setup(struct afs_net *, struct afs_cell *);
-extern void afs_proc_cell_remove(struct afs_net *, struct afs_cell *);
+extern int afs_proc_cell_setup(struct afs_cell *);
+extern void afs_proc_cell_remove(struct afs_cell *);
extern void afs_put_sysnames(struct afs_sysnames *);

/*
@@ -986,7 +990,7 @@ extern bool afs_annotate_server_list(struct afs_server_list *, struct afs_server
* super.c
*/
extern int __init afs_fs_init(void);
-extern void __exit afs_fs_exit(void);
+extern void afs_fs_exit(void);

/*
* vlclient.c
diff --git a/fs/afs/main.c b/fs/afs/main.c
index d7560168b3bf..7d2c1354e2ca 100644
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -15,6 +15,7 @@
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/random.h>
+#include <linux/proc_fs.h>
#define CREATE_TRACE_POINTS
#include "internal.h"

@@ -32,7 +33,7 @@ module_param(rootcell, charp, 0);
MODULE_PARM_DESC(rootcell, "root AFS cell name and VL server IP addr list");

struct workqueue_struct *afs_wq;
-struct afs_net __afs_net;
+static struct proc_dir_entry *afs_proc_symlink;

#if defined(CONFIG_ALPHA)
const char afs_init_sysname[] = "alpha_linux26";
@@ -67,11 +68,13 @@ const char afs_init_sysname[] = "unknown_linux26";
/*
* Initialise an AFS network namespace record.
*/
-static int __net_init afs_net_init(struct afs_net *net)
+static int __net_init afs_net_init(struct net *net_ns)
{
struct afs_sysnames *sysnames;
+ struct afs_net *net = afs_net(net_ns);
int ret;

+ net->net = net_ns;
net->live = true;
generate_random_uuid((unsigned char *)&net->uuid);

@@ -142,8 +145,10 @@ static int __net_init afs_net_init(struct afs_net *net)
/*
* Clean up and destroy an AFS network namespace record.
*/
-static void __net_exit afs_net_exit(struct afs_net *net)
+static void __net_exit afs_net_exit(struct net *net_ns)
{
+ struct afs_net *net = afs_net(net_ns);
+
net->live = false;
afs_cell_purge(net);
afs_purge_servers(net);
@@ -152,6 +157,13 @@ static void __net_exit afs_net_exit(struct afs_net *net)
afs_put_sysnames(net->sysnames);
}

+static struct pernet_operations afs_net_ops = {
+ .init = afs_net_init,
+ .exit = afs_net_exit,
+ .id = &afs_net_id,
+ .size = sizeof(struct afs_net),
+};
+
/*
* initialise the AFS client FS module
*/
@@ -178,7 +190,7 @@ static int __init afs_init(void)
goto error_cache;
#endif

- ret = afs_net_init(&__afs_net);
+ ret = register_pernet_subsys(&afs_net_ops);
if (ret < 0)
goto error_net;

@@ -187,10 +199,18 @@ static int __init afs_init(void)
if (ret < 0)
goto error_fs;

+ afs_proc_symlink = proc_symlink("fs/afs", NULL, "../self/net/afs");
+ if (IS_ERR(afs_proc_symlink)) {
+ ret = PTR_ERR(afs_proc_symlink);
+ goto error_proc;
+ }
+
return ret;

+error_proc:
+ afs_fs_exit();
error_fs:
- afs_net_exit(&__afs_net);
+ unregister_pernet_subsys(&afs_net_ops);
error_net:
#ifdef CONFIG_AFS_FSCACHE
fscache_unregister_netfs(&afs_cache_netfs);
@@ -219,8 +239,9 @@ static void __exit afs_exit(void)
{
printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 unregistering.\n");

+ proc_remove(afs_proc_symlink);
afs_fs_exit();
- afs_net_exit(&__afs_net);
+ unregister_pernet_subsys(&afs_net_ops);
#ifdef CONFIG_AFS_FSCACHE
fscache_unregister_netfs(&afs_cache_netfs);
#endif
diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index 839a22280606..cc7c48a5b743 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -17,14 +17,16 @@
#include <linux/uaccess.h>
#include "internal.h"

-static inline struct afs_net *afs_proc2net(struct file *f)
+static inline struct afs_net *afs_proc2net_get(struct file *f)
{
- return &__afs_net;
+ struct net *net_ns = get_proc_net(file_inode(f));
+
+ return net_ns ? afs_net(net_ns) : NULL;
}

static inline struct afs_net *afs_seq2net(struct seq_file *m)
{
- return &__afs_net; // TODO: use seq_file_net(m)
+ return afs_net(seq_file_net(m));
}

static int afs_proc_cells_open(struct inode *inode, struct file *file);
@@ -161,7 +163,7 @@ int afs_proc_init(struct afs_net *net)
{
_enter("");

- net->proc_afs = proc_mkdir("fs/afs", NULL);
+ net->proc_afs = proc_net_mkdir(net->net, "afs", net->net->proc_net);
if (!net->proc_afs)
goto error_dir;

@@ -196,16 +198,8 @@ void afs_proc_cleanup(struct afs_net *net)
*/
static int afs_proc_cells_open(struct inode *inode, struct file *file)
{
- struct seq_file *m;
- int ret;
-
- ret = seq_open(file, &afs_proc_cells_ops);
- if (ret < 0)
- return ret;
-
- m = file->private_data;
- m->private = PDE_DATA(inode);
- return 0;
+ return seq_open_net(inode, file, &afs_proc_cells_ops,
+ sizeof(struct seq_net_private));
}

/*
@@ -266,7 +260,8 @@ static int afs_proc_cells_show(struct seq_file *m, void *v)
static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
size_t size, loff_t *_pos)
{
- struct afs_net *net = afs_proc2net(file);
+ struct afs_net *net;
+ struct net *net_ns = NULL;
char *kbuf, *name, *args;
int ret;

@@ -305,6 +300,12 @@ static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
/* determine command to perform */
_debug("cmd=%s name=%s args=%s", kbuf, name, args);

+ ret = -ESTALE;
+ net_ns = get_proc_net(file_inode(file));
+ if (!net_ns)
+ goto done;
+ net = afs_net(net_ns);
+
if (strcmp(kbuf, "add") == 0) {
struct afs_cell *cell;

@@ -324,6 +325,7 @@ static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
ret = size;

done:
+ put_net(net_ns);
kfree(kbuf);
_leave(" = %d", ret);
return ret;
@@ -338,15 +340,24 @@ static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
size_t size, loff_t *_pos)
{
struct afs_cell *cell;
- struct afs_net *net = afs_proc2net(file);
+ struct afs_net *net;
+ struct net *net_ns = NULL;
unsigned int seq = 0;
char name[AFS_MAXCELLNAME + 1];
int len;

if (*_pos > 0)
return 0;
- if (!net->ws_cell)
- return 0;
+
+ net_ns = get_proc_net(file_inode(file));
+ if (!net_ns)
+ return -ESTALE;
+ net = afs_net(net_ns);
+
+ if (!net->ws_cell) {
+ len = 0;
+ goto out;
+ }

rcu_read_lock();
do {
@@ -362,14 +373,18 @@ static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
rcu_read_unlock();

if (!len)
- return 0;
+ goto out;

name[len++] = '\n';
if (len > size)
len = size;
- if (copy_to_user(buf, name, len) != 0)
- return -EFAULT;
+ if (copy_to_user(buf, name, len) != 0) {
+ len = -EFAULT;
+ goto out;
+ }
*_pos = 1;
+out:
+ put_net(net_ns);
return len;
}

@@ -381,7 +396,8 @@ static ssize_t afs_proc_rootcell_write(struct file *file,
const char __user *buf,
size_t size, loff_t *_pos)
{
- struct afs_net *net = afs_proc2net(file);
+ struct afs_net *net;
+ struct net *net_ns = NULL;
char *kbuf, *s;
int ret;

@@ -407,6 +423,12 @@ static ssize_t afs_proc_rootcell_write(struct file *file,
/* determine command to perform */
_debug("rootcell=%s", kbuf);

+ ret = -ESTALE;
+ net_ns = get_proc_net(file_inode(file));
+ if (!net_ns)
+ goto out;
+ net = afs_net(net_ns);
+
ret = afs_cell_init(net, kbuf);
if (ret >= 0)
ret = size; /* consume everything, always */
@@ -420,13 +442,14 @@ static ssize_t afs_proc_rootcell_write(struct file *file,
/*
* initialise /proc/fs/afs/<cell>/
*/
-int afs_proc_cell_setup(struct afs_net *net, struct afs_cell *cell)
+int afs_proc_cell_setup(struct afs_cell *cell)
{
struct proc_dir_entry *dir;
+ struct afs_net *net = cell->net;

_enter("%p{%s},%p", cell, cell->name, net->proc_afs);

- dir = proc_mkdir(cell->name, net->proc_afs);
+ dir = proc_net_mkdir(net->net, cell->name, net->proc_afs);
if (!dir)
goto error_dir;

@@ -449,12 +472,12 @@ int afs_proc_cell_setup(struct afs_net *net, struct afs_cell *cell)
/*
* remove /proc/fs/afs/<cell>/
*/
-void afs_proc_cell_remove(struct afs_net *net, struct afs_cell *cell)
+void afs_proc_cell_remove(struct afs_cell *cell)
{
- _enter("");
+ struct afs_net *net = cell->net;

+ _enter("");
remove_proc_subtree(cell->name, net->proc_afs);
-
_leave("");
}

@@ -471,7 +494,8 @@ static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file)
if (!cell)
return -ENOENT;

- ret = seq_open(file, &afs_proc_cell_volumes_ops);
+ ret = seq_open_net(inode, file, &afs_proc_cell_volumes_ops,
+ sizeof(struct seq_net_private));
if (ret < 0)
return ret;

@@ -560,7 +584,8 @@ static int afs_proc_cell_vlservers_open(struct inode *inode, struct file *file)
if (!cell)
return -ENOENT;

- ret = seq_open(file, &afs_proc_cell_vlservers_ops);
+ ret = seq_open_net(inode, file, &afs_proc_cell_vlservers_ops,
+ sizeof(struct seq_net_private));
if (ret<0)
return ret;

@@ -649,7 +674,8 @@ static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
*/
static int afs_proc_servers_open(struct inode *inode, struct file *file)
{
- return seq_open(file, &afs_proc_servers_ops);
+ return seq_open_net(inode, file, &afs_proc_servers_ops,
+ sizeof(struct seq_net_private));
}

/*
@@ -729,7 +755,8 @@ static int afs_proc_sysname_open(struct inode *inode, struct file *file)
struct seq_file *m;
int ret;

- ret = seq_open(file, &afs_proc_sysname_ops);
+ ret = seq_open_net(inode, file, &afs_proc_sysname_ops,
+ sizeof(struct seq_net_private));
if (ret < 0)
return ret;

diff --git a/fs/afs/super.c b/fs/afs/super.c
index 6ab0b79e061e..f56070a9c606 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -48,6 +48,8 @@ struct file_system_type afs_fs_type = {
};
MODULE_ALIAS_FS("afs");

+int afs_net_id;
+
static const struct super_operations afs_super_ops = {
.statfs = afs_statfs,
.alloc_inode = afs_alloc_inode,
@@ -117,7 +119,7 @@ int __init afs_fs_init(void)
/*
* clean up the filesystem
*/
-void __exit afs_fs_exit(void)
+void afs_fs_exit(void)
{
_enter("");

@@ -391,7 +393,7 @@ static int afs_test_super(struct super_block *sb, struct fs_context *fc)
struct afs_fs_context *ctx = container_of(fc, struct afs_fs_context, fc);
struct afs_super_info *as = AFS_FS_S(sb);

- return (as->net == ctx->net &&
+ return (as->net_ns == ctx->fc.net_ns &&
as->volume &&
as->volume->vid == ctx->volume->vid);
}
@@ -477,7 +479,7 @@ static struct afs_super_info *afs_alloc_sbi(struct afs_fs_context *ctx)

as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (as) {
- as->net = afs_get_net(ctx->net);
+ as->net_ns = get_net(ctx->fc.net_ns);
if (ctx->dyn_root) {
as->dyn_root = true;
} else {
@@ -492,8 +494,8 @@ static void afs_destroy_sbi(struct afs_super_info *as)
{
if (as) {
afs_put_volume(as->cell, as->volume);
- afs_put_cell(as->net, as->cell);
- afs_put_net(as->net);
+ afs_put_cell(afs_net(as->net_ns), as->cell);
+ put_net(as->net_ns);
kfree(as);
}
}
@@ -506,7 +508,8 @@ static void afs_kill_super(struct super_block *sb)
* deactivating the superblock.
*/
if (as->volume)
- afs_clear_callback_interests(as->net, as->volume->servers);
+ afs_clear_callback_interests(afs_net(as->net_ns),
+ as->volume->servers);
kill_anon_super(sb);
if (as->volume)
afs_deactivate_volume(as->volume);
@@ -574,7 +577,6 @@ static void afs_free_fc(struct fs_context *fc)

afs_put_volume(ctx->cell, ctx->volume);
afs_put_cell(ctx->net, ctx->cell);
- afs_put_net(ctx->net);
afs_destroy_sbi(ctx->as);
key_put(ctx->key);
}
@@ -595,19 +597,19 @@ static int afs_init_fs_context(struct fs_context *fc, struct super_block *src_sb
struct afs_fs_context *ctx = container_of(fc, struct afs_fs_context, fc);
struct afs_super_info *src_as;
struct afs_cell *cell;
+ struct net *net_ns;

if (current->nsproxy->net_ns != &init_net)
return -EINVAL;
+ ctx->type = AFSVL_ROVOL;

- if (src_sb) {
- src_as = AFS_FS_S(src_sb);
- if (src_as) {
- ctx->net = afs_get_net(src_as->net);
- ctx->cell = afs_get_cell(src_as->cell);
- ctx->volume = __afs_get_volume(src_as->volume);
- }
- } else {
- ctx->net = afs_get_net(&__afs_net);
+ switch (ctx->fc.purpose) {
+ case FS_CONTEXT_FOR_USER_MOUNT:
+ case FS_CONTEXT_FOR_KERNEL_MOUNT:
+ ctx->fc.net_ns = maybe_get_net(current->nsproxy->net_ns);
+ if (!ctx->fc.net_ns)
+ return -ESTALE;
+ ctx->net = afs_net(ctx->fc.net_ns);

/* Default to the workstation cell. */
rcu_read_lock();
@@ -616,6 +618,30 @@ static int afs_init_fs_context(struct fs_context *fc, struct super_block *src_sb
if (IS_ERR(cell))
cell = NULL;
ctx->cell = cell;
+ break;
+
+ case FS_CONTEXT_FOR_SUBMOUNT:
+ if (!src_sb)
+ return -EINVAL;
+
+ src_as = AFS_FS_S(src_sb);
+ ASSERT(src_as);
+
+ net_ns = maybe_get_net(src_as->net_ns);
+ if (!net_ns)
+ return -ESTALE;
+ ctx->fc.net_ns = net_ns;
+ ctx->net = afs_net(net_ns);
+ if (src_as->cell)
+ ctx->cell = afs_get_cell(src_as->cell);
+ if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) {
+ ctx->type = AFSVL_RWVOL;
+ ctx->force = true;
+ }
+ break;
+
+ case FS_CONTEXT_FOR_RECONFIGURE:
+ break;
}

ctx->fc.ops = &afs_context_ops;