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Manoj NaikTrond Myklebust
Manoj Naik
authored and
Trond Myklebust
committed
NFSv4: Ensure client submounts when following a referral
Set up mountpoint when hitting a referral on moved error by getting fs_locations. Signed-off-by: Manoj Naik <manoj@almaden.ibm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
1 parent 61f5164 commit 9cdb388

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2 files changed

+269
-3
lines changed

2 files changed

+269
-3
lines changed

‎fs/nfs/inode.c

Lines changed: 267 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -36,6 +36,8 @@
3636
#include <linux/mount.h>
3737
#include <linux/nfs_idmap.h>
3838
#include <linux/vfs.h>
39+
#include <linux/inet.h>
40+
#include <linux/nfs_xdr.h>
3941

4042
#include <asm/system.h>
4143
#include <asm/uaccess.h>
@@ -1714,6 +1716,10 @@ struct nfs_clone_mount {
17141716
const struct dentry *dentry;
17151717
struct nfs_fh *fh;
17161718
struct nfs_fattr *fattr;
1719+
char *hostname;
1720+
char *mnt_path;
1721+
struct sockaddr_in *addr;
1722+
rpc_authflavor_t authflavor;
17171723
};
17181724

17191725
static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data,
@@ -1724,17 +1730,19 @@ static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data,
17241730
struct nfs_server *parent = NFS_SB(data->sb);
17251731
struct super_block *sb = ERR_PTR(-EINVAL);
17261732
void *err = ERR_PTR(-ENOMEM);
1733+
char *hostname;
17271734
int len;
17281735

17291736
server = kmalloc(sizeof(struct nfs_server), GFP_KERNEL);
17301737
if (server == NULL)
17311738
goto out_err;
17321739
memcpy(server, parent, sizeof(*server));
1733-
len = strlen(parent->hostname) + 1;
1740+
hostname = (data->hostname != NULL) ? data->hostname : parent->hostname;
1741+
len = strlen(hostname) + 1;
17341742
server->hostname = kmalloc(len, GFP_KERNEL);
17351743
if (server->hostname == NULL)
17361744
goto free_server;
1737-
memcpy(server->hostname, parent->hostname, len);
1745+
memcpy(server->hostname, hostname, len);
17381746
if (rpciod_up() != 0)
17391747
goto free_hostname;
17401748

@@ -2458,7 +2466,8 @@ static inline void unregister_nfs4fs(void)
24582466
nfs_unregister_sysctl();
24592467
}
24602468
#else
2461-
#define nfs4_clone_client(a,b) ERR_PTR(-EINVAL)
2469+
#define nfs4_fill_sb(a,b) ERR_PTR(-EINVAL)
2470+
#define nfs4_fill_super(a,b) ERR_PTR(-EINVAL)
24622471
#define nfs4_init_once(nfsi) \
24632472
do { } while (0)
24642473
#define register_nfs4fs() (0)
@@ -2521,6 +2530,261 @@ struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
25212530
return mnt;
25222531
}
25232532

2533+
/* Check if fs_root is valid */
2534+
static inline char *nfs4_pathname_string(struct nfs4_pathname *pathname, char *buffer, ssize_t buflen)
2535+
{
2536+
char *end = buffer + buflen;
2537+
int n;
2538+
2539+
*--end = '\0';
2540+
buflen--;
2541+
2542+
n = pathname->ncomponents;
2543+
while (--n >= 0) {
2544+
struct nfs4_string *component = &pathname->components[n];
2545+
buflen -= component->len + 1;
2546+
if (buflen < 0)
2547+
goto Elong;
2548+
end -= component->len;
2549+
memcpy(end, component->data, component->len);
2550+
*--end = '/';
2551+
}
2552+
return end;
2553+
Elong:
2554+
return ERR_PTR(-ENAMETOOLONG);
2555+
}
2556+
2557+
/* Check if the string represents a "valid" IPv4 address */
2558+
static inline int valid_ipaddr4(const char *buf)
2559+
{
2560+
int rc, count, in[4];
2561+
2562+
rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
2563+
if (rc != 4)
2564+
return -EINVAL;
2565+
for (count = 0; count < 4; count++) {
2566+
if (in[count] > 255)
2567+
return -EINVAL;
2568+
}
2569+
return 0;
2570+
}
2571+
2572+
static struct super_block *nfs4_referral_sb(struct nfs_server *server, struct nfs_clone_mount *data)
2573+
{
2574+
struct super_block *sb = ERR_PTR(-ENOMEM);
2575+
int len;
2576+
2577+
len = strlen(data->mnt_path) + 1;
2578+
server->mnt_path = kmalloc(len, GFP_KERNEL);
2579+
if (server->mnt_path == NULL)
2580+
goto err;
2581+
memcpy(server->mnt_path, data->mnt_path, len);
2582+
memcpy(&server->addr, data->addr, sizeof(struct sockaddr_in));
2583+
2584+
sb = sget(&nfs4_fs_type, nfs4_compare_super, nfs_set_super, server);
2585+
if (IS_ERR(sb) || sb->s_root)
2586+
goto free_path;
2587+
return sb;
2588+
free_path:
2589+
kfree(server->mnt_path);
2590+
err:
2591+
server->mnt_path = NULL;
2592+
return sb;
2593+
}
2594+
2595+
static struct nfs_server *nfs4_referral_server(struct super_block *sb, struct nfs_clone_mount *data)
2596+
{
2597+
struct nfs_server *server = NFS_SB(sb);
2598+
struct rpc_timeout timeparms;
2599+
int proto, timeo, retrans;
2600+
void *err;
2601+
2602+
proto = IPPROTO_TCP;
2603+
/* Since we are following a referral and there may be alternatives,
2604+
set the timeouts and retries to low values */
2605+
timeo = 2;
2606+
retrans = 1;
2607+
nfs_init_timeout_values(&timeparms, proto, timeo, retrans);
2608+
2609+
server->client = nfs4_create_client(server, &timeparms, proto, data->authflavor);
2610+
if (IS_ERR((err = server->client)))
2611+
goto out_err;
2612+
2613+
sb->s_time_gran = 1;
2614+
sb->s_op = &nfs4_sops;
2615+
err = ERR_PTR(nfs_sb_init(sb, data->authflavor));
2616+
if (!IS_ERR(err))
2617+
return server;
2618+
out_err:
2619+
return (struct nfs_server *)err;
2620+
}
2621+
2622+
static struct super_block *nfs_referral_nfs4_sb(struct file_system_type *fs_type,
2623+
int flags, const char *dev_name, void *raw_data)
2624+
{
2625+
struct nfs_clone_mount *data = raw_data;
2626+
return nfs_clone_generic_sb(data, nfs4_referral_sb, nfs4_referral_server);
2627+
}
2628+
2629+
static struct file_system_type nfs_referral_nfs4_fs_type = {
2630+
.owner = THIS_MODULE,
2631+
.name = "nfs4",
2632+
.get_sb = nfs_referral_nfs4_sb,
2633+
.kill_sb = nfs4_kill_super,
2634+
.fs_flags = FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
2635+
};
2636+
2637+
/**
2638+
* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
2639+
* @mnt_parent - mountpoint of parent directory
2640+
* @dentry - parent directory
2641+
* @fspath - fs path returned in fs_locations
2642+
* @mntpath - mount path to new server
2643+
* @hostname - hostname of new server
2644+
* @addr - host addr of new server
2645+
*
2646+
*/
2647+
struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
2648+
const struct dentry *dentry, struct nfs4_fs_locations *locations)
2649+
{
2650+
struct vfsmount *mnt = ERR_PTR(-ENOENT);
2651+
struct nfs_clone_mount mountdata = {
2652+
.sb = mnt_parent->mnt_sb,
2653+
.dentry = dentry,
2654+
.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
2655+
};
2656+
char *page, *page2;
2657+
char *path, *fs_path;
2658+
char *devname;
2659+
int loc, s;
2660+
2661+
if (locations == NULL || locations->nlocations <= 0)
2662+
goto out;
2663+
2664+
dprintk("%s: referral at %s/%s\n", __FUNCTION__,
2665+
dentry->d_parent->d_name.name, dentry->d_name.name);
2666+
2667+
/* Ensure fs path is a prefix of current dentry path */
2668+
page = (char *) __get_free_page(GFP_USER);
2669+
if (page == NULL)
2670+
goto out;
2671+
page2 = (char *) __get_free_page(GFP_USER);
2672+
if (page2 == NULL)
2673+
goto out;
2674+
2675+
path = nfs4_path(dentry, page, PAGE_SIZE);
2676+
if (IS_ERR(path))
2677+
goto out_free;
2678+
2679+
fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
2680+
if (IS_ERR(fs_path))
2681+
goto out_free;
2682+
2683+
if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
2684+
dprintk("%s: path %s does not begin with fsroot %s\n", __FUNCTION__, path, fs_path);
2685+
goto out_free;
2686+
}
2687+
2688+
devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);
2689+
if (IS_ERR(devname)) {
2690+
mnt = (struct vfsmount *)devname;
2691+
goto out_free;
2692+
}
2693+
2694+
loc = 0;
2695+
while (loc < locations->nlocations && IS_ERR(mnt)) {
2696+
struct nfs4_fs_location *location = &locations->locations[loc];
2697+
char *mnt_path;
2698+
2699+
if (location == NULL || location->nservers <= 0 ||
2700+
location->rootpath.ncomponents == 0) {
2701+
loc++;
2702+
continue;
2703+
}
2704+
2705+
mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
2706+
if (IS_ERR(mnt_path)) {
2707+
loc++;
2708+
continue;
2709+
}
2710+
mountdata.mnt_path = mnt_path;
2711+
2712+
s = 0;
2713+
while (s < location->nservers) {
2714+
struct sockaddr_in addr = {};
2715+
2716+
if (location->servers[s].len <= 0 ||
2717+
valid_ipaddr4(location->servers[s].data) < 0) {
2718+
s++;
2719+
continue;
2720+
}
2721+
2722+
mountdata.hostname = location->servers[s].data;
2723+
addr.sin_addr.s_addr = in_aton(mountdata.hostname);
2724+
addr.sin_family = AF_INET;
2725+
addr.sin_port = htons(NFS_PORT);
2726+
mountdata.addr = &addr;
2727+
2728+
mnt = vfs_kern_mount(&nfs_referral_nfs4_fs_type, 0, devname, &mountdata);
2729+
if (!IS_ERR(mnt)) {
2730+
break;
2731+
}
2732+
s++;
2733+
}
2734+
loc++;
2735+
}
2736+
2737+
out_free:
2738+
free_page((unsigned long)page);
2739+
free_page((unsigned long)page2);
2740+
out:
2741+
dprintk("%s: done\n", __FUNCTION__);
2742+
return mnt;
2743+
}
2744+
2745+
/*
2746+
* nfs_do_refmount - handle crossing a referral on server
2747+
* @dentry - dentry of referral
2748+
* @nd - nameidata info
2749+
*
2750+
*/
2751+
struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
2752+
{
2753+
struct vfsmount *mnt = ERR_PTR(-ENOENT);
2754+
struct dentry *parent;
2755+
struct nfs4_fs_locations *fs_locations = NULL;
2756+
struct page *page;
2757+
int err;
2758+
2759+
/* BUG_ON(IS_ROOT(dentry)); */
2760+
dprintk("%s: enter\n", __FUNCTION__);
2761+
2762+
page = alloc_page(GFP_KERNEL);
2763+
if (page == NULL)
2764+
goto out;
2765+
2766+
fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
2767+
if (fs_locations == NULL)
2768+
goto out_free;
2769+
2770+
/* Get locations */
2771+
parent = dget_parent(dentry);
2772+
dprintk("%s: getting locations for %s/%s\n", __FUNCTION__, parent->d_name.name, dentry->d_name.name);
2773+
err = nfs4_proc_fs_locations(parent->d_inode, dentry, fs_locations, page);
2774+
dput(parent);
2775+
if (err != 0 || fs_locations->nlocations <= 0 ||
2776+
fs_locations->fs_path.ncomponents <= 0)
2777+
goto out_free;
2778+
2779+
mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
2780+
out_free:
2781+
__free_page(page);
2782+
kfree(fs_locations);
2783+
out:
2784+
dprintk("%s: done\n", __FUNCTION__);
2785+
return mnt;
2786+
}
2787+
25242788
extern int nfs_init_nfspagecache(void);
25252789
extern void nfs_destroy_nfspagecache(void);
25262790
extern int nfs_init_readpagecache(void);

‎include/linux/nfs_fs.h

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -317,6 +317,8 @@ extern struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
317317
const struct dentry *dentry,
318318
struct nfs_fh *fh,
319319
struct nfs_fattr *fattr);
320+
extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent,
321+
struct dentry *dentry);
320322

321323
/* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
322324
extern u32 root_nfs_parse_addr(char *name); /*__init*/

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