kernel-fxtec-pro1x/fs/nfsd/nfsctl.c
David Howells 454e2398be [PATCH] VFS: Permit filesystem to override root dentry on mount
Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.

The filesystem is then required to manually set the superblock and root dentry
pointers.  For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).

The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.

This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing.  In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.

The patch also makes the following changes:

 (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
     pointer argument and return an integer, so most filesystems have to change
     very little.

 (*) If one of the convenience function is not used, then get_sb() should
     normally call simple_set_mnt() to instantiate the vfsmount. This will
     always return 0, and so can be tail-called from get_sb().

 (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
     dcache upon superblock destruction rather than shrink_dcache_anon().

     This is required because the superblock may now have multiple trees that
     aren't actually bound to s_root, but that still need to be cleaned up. The
     currently called functions assume that the whole tree is rooted at s_root,
     and that anonymous dentries are not the roots of trees which results in
     dentries being left unculled.

     However, with the way NFS superblock sharing are currently set to be
     implemented, these assumptions are violated: the root of the filesystem is
     simply a dummy dentry and inode (the real inode for '/' may well be
     inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
     with child trees.

     [*] Anonymous until discovered from another tree.

 (*) The documentation has been adjusted, including the additional bit of
     changing ext2_* into foo_* in the documentation.

[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:45 -07:00

554 lines
13 KiB
C

/*
* linux/fs/nfsd/nfsctl.c
*
* Syscall interface to knfsd.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/linkage.h>
#include <linux/time.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/nfs.h>
#include <linux/nfsd_idmap.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/cache.h>
#include <linux/nfsd/xdr.h>
#include <linux/nfsd/syscall.h>
#include <linux/nfsd/interface.h>
#include <asm/uaccess.h>
unsigned int nfsd_versbits = ~0;
/*
* We have a single directory with 9 nodes in it.
*/
enum {
NFSD_Root = 1,
NFSD_Svc,
NFSD_Add,
NFSD_Del,
NFSD_Export,
NFSD_Unexport,
NFSD_Getfd,
NFSD_Getfs,
NFSD_List,
NFSD_Fh,
NFSD_Threads,
NFSD_Versions,
/*
* The below MUST come last. Otherwise we leave a hole in nfsd_files[]
* with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
*/
#ifdef CONFIG_NFSD_V4
NFSD_Leasetime,
NFSD_RecoveryDir,
#endif
};
/*
* write() for these nodes.
*/
static ssize_t write_svc(struct file *file, char *buf, size_t size);
static ssize_t write_add(struct file *file, char *buf, size_t size);
static ssize_t write_del(struct file *file, char *buf, size_t size);
static ssize_t write_export(struct file *file, char *buf, size_t size);
static ssize_t write_unexport(struct file *file, char *buf, size_t size);
static ssize_t write_getfd(struct file *file, char *buf, size_t size);
static ssize_t write_getfs(struct file *file, char *buf, size_t size);
static ssize_t write_filehandle(struct file *file, char *buf, size_t size);
static ssize_t write_threads(struct file *file, char *buf, size_t size);
static ssize_t write_versions(struct file *file, char *buf, size_t size);
#ifdef CONFIG_NFSD_V4
static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
#endif
static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Svc] = write_svc,
[NFSD_Add] = write_add,
[NFSD_Del] = write_del,
[NFSD_Export] = write_export,
[NFSD_Unexport] = write_unexport,
[NFSD_Getfd] = write_getfd,
[NFSD_Getfs] = write_getfs,
[NFSD_Fh] = write_filehandle,
[NFSD_Threads] = write_threads,
[NFSD_Versions] = write_versions,
#ifdef CONFIG_NFSD_V4
[NFSD_Leasetime] = write_leasetime,
[NFSD_RecoveryDir] = write_recoverydir,
#endif
};
static ssize_t nfsctl_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
{
ino_t ino = file->f_dentry->d_inode->i_ino;
char *data;
ssize_t rv;
if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])
return -EINVAL;
data = simple_transaction_get(file, buf, size);
if (IS_ERR(data))
return PTR_ERR(data);
rv = write_op[ino](file, data, size);
if (rv>0) {
simple_transaction_set(file, rv);
rv = size;
}
return rv;
}
static ssize_t nfsctl_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
{
if (! file->private_data) {
/* An attempt to read a transaction file without writing
* causes a 0-byte write so that the file can return
* state information
*/
ssize_t rv = nfsctl_transaction_write(file, buf, 0, pos);
if (rv < 0)
return rv;
}
return simple_transaction_read(file, buf, size, pos);
}
static const struct file_operations transaction_ops = {
.write = nfsctl_transaction_write,
.read = nfsctl_transaction_read,
.release = simple_transaction_release,
};
extern struct seq_operations nfs_exports_op;
static int exports_open(struct inode *inode, struct file *file)
{
return seq_open(file, &nfs_exports_op);
}
static const struct file_operations exports_operations = {
.open = exports_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
/*----------------------------------------------------------------------------*/
/*
* payload - write methods
* If the method has a response, the response should be put in buf,
* and the length returned. Otherwise return 0 or and -error.
*/
static ssize_t write_svc(struct file *file, char *buf, size_t size)
{
struct nfsctl_svc *data;
if (size < sizeof(*data))
return -EINVAL;
data = (struct nfsctl_svc*) buf;
return nfsd_svc(data->svc_port, data->svc_nthreads);
}
static ssize_t write_add(struct file *file, char *buf, size_t size)
{
struct nfsctl_client *data;
if (size < sizeof(*data))
return -EINVAL;
data = (struct nfsctl_client *)buf;
return exp_addclient(data);
}
static ssize_t write_del(struct file *file, char *buf, size_t size)
{
struct nfsctl_client *data;
if (size < sizeof(*data))
return -EINVAL;
data = (struct nfsctl_client *)buf;
return exp_delclient(data);
}
static ssize_t write_export(struct file *file, char *buf, size_t size)
{
struct nfsctl_export *data;
if (size < sizeof(*data))
return -EINVAL;
data = (struct nfsctl_export*)buf;
return exp_export(data);
}
static ssize_t write_unexport(struct file *file, char *buf, size_t size)
{
struct nfsctl_export *data;
if (size < sizeof(*data))
return -EINVAL;
data = (struct nfsctl_export*)buf;
return exp_unexport(data);
}
static ssize_t write_getfs(struct file *file, char *buf, size_t size)
{
struct nfsctl_fsparm *data;
struct sockaddr_in *sin;
struct auth_domain *clp;
int err = 0;
struct knfsd_fh *res;
if (size < sizeof(*data))
return -EINVAL;
data = (struct nfsctl_fsparm*)buf;
err = -EPROTONOSUPPORT;
if (data->gd_addr.sa_family != AF_INET)
goto out;
sin = (struct sockaddr_in *)&data->gd_addr;
if (data->gd_maxlen > NFS3_FHSIZE)
data->gd_maxlen = NFS3_FHSIZE;
res = (struct knfsd_fh*)buf;
exp_readlock();
if (!(clp = auth_unix_lookup(sin->sin_addr)))
err = -EPERM;
else {
err = exp_rootfh(clp, data->gd_path, res, data->gd_maxlen);
auth_domain_put(clp);
}
exp_readunlock();
if (err == 0)
err = res->fh_size + (int)&((struct knfsd_fh*)0)->fh_base;
out:
return err;
}
static ssize_t write_getfd(struct file *file, char *buf, size_t size)
{
struct nfsctl_fdparm *data;
struct sockaddr_in *sin;
struct auth_domain *clp;
int err = 0;
struct knfsd_fh fh;
char *res;
if (size < sizeof(*data))
return -EINVAL;
data = (struct nfsctl_fdparm*)buf;
err = -EPROTONOSUPPORT;
if (data->gd_addr.sa_family != AF_INET)
goto out;
err = -EINVAL;
if (data->gd_version < 2 || data->gd_version > NFSSVC_MAXVERS)
goto out;
res = buf;
sin = (struct sockaddr_in *)&data->gd_addr;
exp_readlock();
if (!(clp = auth_unix_lookup(sin->sin_addr)))
err = -EPERM;
else {
err = exp_rootfh(clp, data->gd_path, &fh, NFS_FHSIZE);
auth_domain_put(clp);
}
exp_readunlock();
if (err == 0) {
memset(res,0, NFS_FHSIZE);
memcpy(res, &fh.fh_base, fh.fh_size);
err = NFS_FHSIZE;
}
out:
return err;
}
static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
{
/* request is:
* domain path maxsize
* response is
* filehandle
*
* qword quoting is used, so filehandle will be \x....
*/
char *dname, *path;
int maxsize;
char *mesg = buf;
int len;
struct auth_domain *dom;
struct knfsd_fh fh;
if (buf[size-1] != '\n')
return -EINVAL;
buf[size-1] = 0;
dname = mesg;
len = qword_get(&mesg, dname, size);
if (len <= 0) return -EINVAL;
path = dname+len+1;
len = qword_get(&mesg, path, size);
if (len <= 0) return -EINVAL;
len = get_int(&mesg, &maxsize);
if (len)
return len;
if (maxsize < NFS_FHSIZE)
return -EINVAL;
if (maxsize > NFS3_FHSIZE)
maxsize = NFS3_FHSIZE;
if (qword_get(&mesg, mesg, size)>0)
return -EINVAL;
/* we have all the words, they are in buf.. */
dom = unix_domain_find(dname);
if (!dom)
return -ENOMEM;
len = exp_rootfh(dom, path, &fh, maxsize);
auth_domain_put(dom);
if (len)
return len;
mesg = buf; len = SIMPLE_TRANSACTION_LIMIT;
qword_addhex(&mesg, &len, (char*)&fh.fh_base, fh.fh_size);
mesg[-1] = '\n';
return mesg - buf;
}
extern int nfsd_nrthreads(void);
static ssize_t write_threads(struct file *file, char *buf, size_t size)
{
/* if size > 0, look for a number of threads and call nfsd_svc
* then write out number of threads as reply
*/
char *mesg = buf;
int rv;
if (size > 0) {
int newthreads;
rv = get_int(&mesg, &newthreads);
if (rv)
return rv;
if (newthreads <0)
return -EINVAL;
rv = nfsd_svc(2049, newthreads);
if (rv)
return rv;
}
sprintf(buf, "%d\n", nfsd_nrthreads());
return strlen(buf);
}
static ssize_t write_versions(struct file *file, char *buf, size_t size)
{
/*
* Format:
* [-/+]vers [-/+]vers ...
*/
char *mesg = buf;
char *vers, sign;
int len, num;
ssize_t tlen = 0;
char *sep;
if (size>0) {
if (nfsd_serv)
return -EBUSY;
if (buf[size-1] != '\n')
return -EINVAL;
buf[size-1] = 0;
vers = mesg;
len = qword_get(&mesg, vers, size);
if (len <= 0) return -EINVAL;
do {
sign = *vers;
if (sign == '+' || sign == '-')
num = simple_strtol((vers+1), NULL, 0);
else
num = simple_strtol(vers, NULL, 0);
switch(num) {
case 2:
case 3:
case 4:
if (sign != '-')
NFSCTL_VERSET(nfsd_versbits, num);
else
NFSCTL_VERUNSET(nfsd_versbits, num);
break;
default:
return -EINVAL;
}
vers += len + 1;
tlen += len;
} while ((len = qword_get(&mesg, vers, size)) > 0);
/* If all get turned off, turn them back on, as
* having no versions is BAD
*/
if ((nfsd_versbits & NFSCTL_VERALL)==0)
nfsd_versbits = NFSCTL_VERALL;
}
/* Now write current state into reply buffer */
len = 0;
sep = "";
for (num=2 ; num <= 4 ; num++)
if (NFSCTL_VERISSET(NFSCTL_VERALL, num)) {
len += sprintf(buf+len, "%s%c%d", sep,
NFSCTL_VERISSET(nfsd_versbits, num)?'+':'-',
num);
sep = " ";
}
len += sprintf(buf+len, "\n");
return len;
}
#ifdef CONFIG_NFSD_V4
extern time_t nfs4_leasetime(void);
static ssize_t write_leasetime(struct file *file, char *buf, size_t size)
{
/* if size > 10 seconds, call
* nfs4_reset_lease() then write out the new lease (seconds) as reply
*/
char *mesg = buf;
int rv;
if (size > 0) {
int lease;
rv = get_int(&mesg, &lease);
if (rv)
return rv;
if (lease < 10 || lease > 3600)
return -EINVAL;
nfs4_reset_lease(lease);
}
sprintf(buf, "%ld\n", nfs4_lease_time());
return strlen(buf);
}
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size)
{
char *mesg = buf;
char *recdir;
int len, status;
if (size > PATH_MAX || buf[size-1] != '\n')
return -EINVAL;
buf[size-1] = 0;
recdir = mesg;
len = qword_get(&mesg, recdir, size);
if (len <= 0)
return -EINVAL;
status = nfs4_reset_recoverydir(recdir);
return strlen(buf);
}
#endif
/*----------------------------------------------------------------------------*/
/*
* populating the filesystem.
*/
static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
{
static struct tree_descr nfsd_files[] = {
[NFSD_Svc] = {".svc", &transaction_ops, S_IWUSR},
[NFSD_Add] = {".add", &transaction_ops, S_IWUSR},
[NFSD_Del] = {".del", &transaction_ops, S_IWUSR},
[NFSD_Export] = {".export", &transaction_ops, S_IWUSR},
[NFSD_Unexport] = {".unexport", &transaction_ops, S_IWUSR},
[NFSD_Getfd] = {".getfd", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Getfs] = {".getfs", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_List] = {"exports", &exports_operations, S_IRUGO},
[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},
#ifdef CONFIG_NFSD_V4
[NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
#endif
/* last one */ {""}
};
return simple_fill_super(sb, 0x6e667364, nfsd_files);
}
static int nfsd_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_single(fs_type, flags, data, nfsd_fill_super, mnt);
}
static struct file_system_type nfsd_fs_type = {
.owner = THIS_MODULE,
.name = "nfsd",
.get_sb = nfsd_get_sb,
.kill_sb = kill_litter_super,
};
static int __init init_nfsd(void)
{
int retval;
printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n");
nfsd_stat_init(); /* Statistics */
nfsd_cache_init(); /* RPC reply cache */
nfsd_export_init(); /* Exports table */
nfsd_lockd_init(); /* lockd->nfsd callbacks */
nfs4_state_init(); /* NFSv4 locking state */
nfsd_idmap_init(); /* Name to ID mapping */
if (proc_mkdir("fs/nfs", NULL)) {
struct proc_dir_entry *entry;
entry = create_proc_entry("fs/nfs/exports", 0, NULL);
if (entry)
entry->proc_fops = &exports_operations;
}
retval = register_filesystem(&nfsd_fs_type);
if (retval) {
nfsd_export_shutdown();
nfsd_cache_shutdown();
remove_proc_entry("fs/nfs/exports", NULL);
remove_proc_entry("fs/nfs", NULL);
nfsd_stat_shutdown();
nfsd_lockd_shutdown();
}
return retval;
}
static void __exit exit_nfsd(void)
{
nfsd_export_shutdown();
nfsd_cache_shutdown();
remove_proc_entry("fs/nfs/exports", NULL);
remove_proc_entry("fs/nfs", NULL);
nfsd_stat_shutdown();
nfsd_lockd_shutdown();
nfsd_idmap_shutdown();
unregister_filesystem(&nfsd_fs_type);
}
MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
MODULE_LICENSE("GPL");
module_init(init_nfsd)
module_exit(exit_nfsd)