Skip to content

Commit

Permalink
NFSv4: Ensure client submounts when following a referral
Browse files Browse the repository at this point in the history 
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>
  • Loading branch information
Manoj Naik authored and Trond Myklebust committed Jun 9, 2006
1 parent 61f5164 commit 9cdb388
Show file tree
Hide file tree
Showing 2 changed files with 269 additions and 3 deletions.
270 changes: 267 additions & 3 deletions fs/nfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,8 @@
#include <linux/mount.h>
#include <linux/nfs_idmap.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include <linux/nfs_xdr.h>

#include <asm/system.h>
#include <asm/uaccess.h>
Expand Down Expand Up @@ -1714,6 +1716,10 @@ struct nfs_clone_mount {
const struct dentry *dentry;
struct nfs_fh *fh;
struct nfs_fattr *fattr;
char *hostname;
char *mnt_path;
struct sockaddr_in *addr;
rpc_authflavor_t authflavor;
};

static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data,
Expand All @@ -1724,17 +1730,19 @@ static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data,
struct nfs_server *parent = NFS_SB(data->sb);
struct super_block *sb = ERR_PTR(-EINVAL);
void *err = ERR_PTR(-ENOMEM);
char *hostname;
int len;

server = kmalloc(sizeof(struct nfs_server), GFP_KERNEL);
if (server == NULL)
goto out_err;
memcpy(server, parent, sizeof(*server));
len = strlen(parent->hostname) + 1;
hostname = (data->hostname != NULL) ? data->hostname : parent->hostname;
len = strlen(hostname) + 1;
server->hostname = kmalloc(len, GFP_KERNEL);
if (server->hostname == NULL)
goto free_server;
memcpy(server->hostname, parent->hostname, len);
memcpy(server->hostname, hostname, len);
if (rpciod_up() != 0)
goto free_hostname;

Expand Down Expand Up @@ -2458,7 +2466,8 @@ static inline void unregister_nfs4fs(void)
nfs_unregister_sysctl();
}
#else
#define nfs4_clone_client(a,b) ERR_PTR(-EINVAL)
#define nfs4_fill_sb(a,b) ERR_PTR(-EINVAL)
#define nfs4_fill_super(a,b) ERR_PTR(-EINVAL)
#define nfs4_init_once(nfsi) \
do { } while (0)
#define register_nfs4fs() (0)
Expand Down Expand Up @@ -2521,6 +2530,261 @@ struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
return mnt;
}

/* Check if fs_root is valid */
static inline char *nfs4_pathname_string(struct nfs4_pathname *pathname, char *buffer, ssize_t buflen)
{
char *end = buffer + buflen;
int n;

*--end = '\0';
buflen--;

n = pathname->ncomponents;
while (--n >= 0) {
struct nfs4_string *component = &pathname->components[n];
buflen -= component->len + 1;
if (buflen < 0)
goto Elong;
end -= component->len;
memcpy(end, component->data, component->len);
*--end = '/';
}
return end;
Elong:
return ERR_PTR(-ENAMETOOLONG);
}

/* Check if the string represents a "valid" IPv4 address */
static inline int valid_ipaddr4(const char *buf)
{
int rc, count, in[4];

rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
if (rc != 4)
return -EINVAL;
for (count = 0; count < 4; count++) {
if (in[count] > 255)
return -EINVAL;
}
return 0;
}

static struct super_block *nfs4_referral_sb(struct nfs_server *server, struct nfs_clone_mount *data)
{
struct super_block *sb = ERR_PTR(-ENOMEM);
int len;

len = strlen(data->mnt_path) + 1;
server->mnt_path = kmalloc(len, GFP_KERNEL);
if (server->mnt_path == NULL)
goto err;
memcpy(server->mnt_path, data->mnt_path, len);
memcpy(&server->addr, data->addr, sizeof(struct sockaddr_in));

sb = sget(&nfs4_fs_type, nfs4_compare_super, nfs_set_super, server);
if (IS_ERR(sb) || sb->s_root)
goto free_path;
return sb;
free_path:
kfree(server->mnt_path);
err:
server->mnt_path = NULL;
return sb;
}

static struct nfs_server *nfs4_referral_server(struct super_block *sb, struct nfs_clone_mount *data)
{
struct nfs_server *server = NFS_SB(sb);
struct rpc_timeout timeparms;
int proto, timeo, retrans;
void *err;

proto = IPPROTO_TCP;
/* Since we are following a referral and there may be alternatives,
set the timeouts and retries to low values */
timeo = 2;
retrans = 1;
nfs_init_timeout_values(&timeparms, proto, timeo, retrans);

server->client = nfs4_create_client(server, &timeparms, proto, data->authflavor);
if (IS_ERR((err = server->client)))
goto out_err;

sb->s_time_gran = 1;
sb->s_op = &nfs4_sops;
err = ERR_PTR(nfs_sb_init(sb, data->authflavor));
if (!IS_ERR(err))
return server;
out_err:
return (struct nfs_server *)err;
}

static struct super_block *nfs_referral_nfs4_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data)
{
struct nfs_clone_mount *data = raw_data;
return nfs_clone_generic_sb(data, nfs4_referral_sb, nfs4_referral_server);
}

static struct file_system_type nfs_referral_nfs4_fs_type = {
.owner = THIS_MODULE,
.name = "nfs4",
.get_sb = nfs_referral_nfs4_sb,
.kill_sb = nfs4_kill_super,
.fs_flags = FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};

/**
* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
* @mnt_parent - mountpoint of parent directory
* @dentry - parent directory
* @fspath - fs path returned in fs_locations
* @mntpath - mount path to new server
* @hostname - hostname of new server
* @addr - host addr of new server
*
*/
struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
const struct dentry *dentry, struct nfs4_fs_locations *locations)
{
struct vfsmount *mnt = ERR_PTR(-ENOENT);
struct nfs_clone_mount mountdata = {
.sb = mnt_parent->mnt_sb,
.dentry = dentry,
.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
};
char *page, *page2;
char *path, *fs_path;
char *devname;
int loc, s;

if (locations == NULL || locations->nlocations <= 0)
goto out;

dprintk("%s: referral at %s/%s\n", __FUNCTION__,
dentry->d_parent->d_name.name, dentry->d_name.name);

/* Ensure fs path is a prefix of current dentry path */
page = (char *) __get_free_page(GFP_USER);
if (page == NULL)
goto out;
page2 = (char *) __get_free_page(GFP_USER);
if (page2 == NULL)
goto out;

path = nfs4_path(dentry, page, PAGE_SIZE);
if (IS_ERR(path))
goto out_free;

fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
if (IS_ERR(fs_path))
goto out_free;

if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
dprintk("%s: path %s does not begin with fsroot %s\n", __FUNCTION__, path, fs_path);
goto out_free;
}

devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);
if (IS_ERR(devname)) {
mnt = (struct vfsmount *)devname;
goto out_free;
}

loc = 0;
while (loc < locations->nlocations && IS_ERR(mnt)) {
struct nfs4_fs_location *location = &locations->locations[loc];
char *mnt_path;

if (location == NULL || location->nservers <= 0 ||
location->rootpath.ncomponents == 0) {
loc++;
continue;
}

mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
if (IS_ERR(mnt_path)) {
loc++;
continue;
}
mountdata.mnt_path = mnt_path;

s = 0;
while (s < location->nservers) {
struct sockaddr_in addr = {};

if (location->servers[s].len <= 0 ||
valid_ipaddr4(location->servers[s].data) < 0) {
s++;
continue;
}

mountdata.hostname = location->servers[s].data;
addr.sin_addr.s_addr = in_aton(mountdata.hostname);
addr.sin_family = AF_INET;
addr.sin_port = htons(NFS_PORT);
mountdata.addr = &addr;

mnt = vfs_kern_mount(&nfs_referral_nfs4_fs_type, 0, devname, &mountdata);
if (!IS_ERR(mnt)) {
break;
}
s++;
}
loc++;
}

out_free:
free_page((unsigned long)page);
free_page((unsigned long)page2);
out:
dprintk("%s: done\n", __FUNCTION__);
return mnt;
}

/*
* nfs_do_refmount - handle crossing a referral on server
* @dentry - dentry of referral
* @nd - nameidata info
*
*/
struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
{
struct vfsmount *mnt = ERR_PTR(-ENOENT);
struct dentry *parent;
struct nfs4_fs_locations *fs_locations = NULL;
struct page *page;
int err;

/* BUG_ON(IS_ROOT(dentry)); */
dprintk("%s: enter\n", __FUNCTION__);

page = alloc_page(GFP_KERNEL);
if (page == NULL)
goto out;

fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
if (fs_locations == NULL)
goto out_free;

/* Get locations */
parent = dget_parent(dentry);
dprintk("%s: getting locations for %s/%s\n", __FUNCTION__, parent->d_name.name, dentry->d_name.name);
err = nfs4_proc_fs_locations(parent->d_inode, dentry, fs_locations, page);
dput(parent);
if (err != 0 || fs_locations->nlocations <= 0 ||
fs_locations->fs_path.ncomponents <= 0)
goto out_free;

mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
out_free:
__free_page(page);
kfree(fs_locations);
out:
dprintk("%s: done\n", __FUNCTION__);
return mnt;
}

extern int nfs_init_nfspagecache(void);
extern void nfs_destroy_nfspagecache(void);
extern int nfs_init_readpagecache(void);
Expand Down
2 changes: 2 additions & 0 deletions include/linux/nfs_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -317,6 +317,8 @@ extern struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
const struct dentry *dentry,
struct nfs_fh *fh,
struct nfs_fattr *fattr);
extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent,
struct dentry *dentry);

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

0 comments on commit 9cdb388

Please sign in to comment.