inode.c

Linux Kernel 2.6.9 for OMAP1710

/*
 *  linux/fs/nfs/inode.c
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 *  nfs inode and superblock handling functions
 *
 *  Modularised by Alan Cox <[e-mail]>, while hacking some
 *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
 *
 *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
 *  [e-mail]
 *
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>

#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/stats.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/lockd/bind.h>
#include <linux/smp_lock.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/nfs_idmap.h>
#include <linux/vfs.h>

#include <asm/system.h>
#include <asm/uaccess.h>

#include "delegation.h"

#define NFSDBG_FACILITY		NFSDBG_VFS
#define NFS_PARANOIA 1

/* Maximum number of readahead requests
 * FIXME: this should really be a sysctl so that users may tune it to suit
 *        their needs. People that do NFS over a slow network, might for
 *        instance want to reduce it to something closer to 1 for improved
 *        interactive response.
 */
#define NFS_MAX_READAHEAD	(RPC_DEF_SLOT_TABLE - 1)

static void nfs_invalidate_inode(struct inode *);
static int nfs_update_inode(struct inode *, struct nfs_fattr *, unsigned long);

static struct inode *nfs_alloc_inode(struct super_block *sb);
static void nfs_destroy_inode(struct inode *);
static int nfs_write_inode(struct inode *,int);
static void nfs_delete_inode(struct inode *);
static void nfs_clear_inode(struct inode *);
static void nfs_umount_begin(struct super_block *);
static int  nfs_statfs(struct super_block *, struct kstatfs *);
static int  nfs_show_options(struct seq_file *, struct vfsmount *);

static struct super_operations nfs_sops = { 
	.alloc_inode	= nfs_alloc_inode,
	.destroy_inode	= nfs_destroy_inode,
	.write_inode	= nfs_write_inode,
	.delete_inode	= nfs_delete_inode,
	.statfs		= nfs_statfs,
	.clear_inode	= nfs_clear_inode,
	.umount_begin	= nfs_umount_begin,
	.show_options	= nfs_show_options,
};

/*
 * RPC cruft for NFS
 */
struct rpc_stat			nfs_rpcstat = {
	.program		= &nfs_program
};
static struct rpc_version *	nfs_version[] = {
	NULL,
	NULL,
	&nfs_version2,
#if defined(CONFIG_NFS_V3)
	&nfs_version3,
#elif defined(CONFIG_NFS_V4)
	NULL,
#endif
#if defined(CONFIG_NFS_V4)
	&nfs_version4,
#endif
};

struct rpc_program		nfs_program = {
	.name			= "nfs",
	.number			= NFS_PROGRAM,
	.nrvers			= sizeof(nfs_version) / sizeof(nfs_version[0]),
	.version		= nfs_version,
	.stats			= &nfs_rpcstat,
	.pipe_dir_name		= "/nfs",
};

static inline unsigned long
nfs_fattr_to_ino_t(struct nfs_fattr *fattr)
{
	return nfs_fileid_to_ino_t(fattr->fileid);
}

static int
nfs_write_inode(struct inode *inode, int sync)
{
	int flags = sync ? FLUSH_WAIT : 0;
	int ret;

	ret = nfs_commit_inode(inode, 0, 0, flags);
	if (ret < 0)
		return ret;
	return 0;
}

static void
nfs_delete_inode(struct inode * inode)
{
	dprintk("NFS: delete_inode(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);

	nfs_wb_all(inode);
	/*
	 * The following should never happen...
	 */
	if (nfs_have_writebacks(inode)) {
		printk(KERN_ERR "nfs_delete_inode: inode %ld has pending RPC requests\n", inode->i_ino);
	}

	clear_inode(inode);
}

/*
 * For the moment, the only task for the NFS clear_inode method is to
 * release the mmap credential
 */
static void
nfs_clear_inode(struct inode *inode)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct rpc_cred *cred;

	nfs_wb_all(inode);
	BUG_ON (!list_empty(&nfsi->open_files));
	cred = nfsi->cache_access.cred;
	if (cred)
		put_rpccred(cred);
	BUG_ON(atomic_read(&nfsi->data_updates) != 0);
}

void
nfs_umount_begin(struct super_block *sb)
{
	struct nfs_server *server = NFS_SB(sb);
	struct rpc_clnt	*rpc;

	/* -EIO all pending I/O */
	if ((rpc = server->client) != NULL)
		rpc_killall_tasks(rpc);
}


static inline unsigned long
nfs_block_bits(unsigned long bsize, unsigned char *nrbitsp)
{
	/* make sure blocksize is a power of two */
	if ((bsize & (bsize - 1)) || nrbitsp) {
		unsigned char	nrbits;

		for (nrbits = 31; nrbits && !(bsize & (1 << nrbits)); nrbits--)
			;
		bsize = 1 << nrbits;
		if (nrbitsp)
			*nrbitsp = nrbits;
	}

	return bsize;
}

/*
 * Calculate the number of 512byte blocks used.
 */
static inline unsigned long
nfs_calc_block_size(u64 tsize)
{
	loff_t used = (tsize + 511) >> 9;
	return (used > ULONG_MAX) ? ULONG_MAX : used;
}

/*
 * Compute and set NFS server blocksize
 */
static inline unsigned long
nfs_block_size(unsigned long bsize, unsigned char *nrbitsp)
{
	if (bsize < 1024)
		bsize = NFS_DEF_FILE_IO_BUFFER_SIZE;
	else if (bsize >= NFS_MAX_FILE_IO_BUFFER_SIZE)
		bsize = NFS_MAX_FILE_IO_BUFFER_SIZE;

	return nfs_block_bits(bsize, nrbitsp);
}

/*
 * Obtain the root inode of the file system.
 */
static struct inode *
nfs_get_root(struct super_block *sb, struct nfs_fh *rootfh, struct nfs_fsinfo *fsinfo)
{
	struct nfs_server	*server = NFS_SB(sb);
	struct inode *rooti;
	int			error;

	error = server->rpc_ops->getroot(server, rootfh, fsinfo);
	if (error < 0) {
		dprintk("nfs_get_root: getattr error = %d\n", -error);
		return ERR_PTR(error);
	}

	rooti = nfs_fhget(sb, rootfh, fsinfo->fattr);
	if (!rooti)
		return ERR_PTR(-ENOMEM);
	return rooti;
}

/*
 * Do NFS version-independent mount processing, and sanity checking
 */
static int
nfs_sb_init(struct super_block *sb, rpc_authflavor_t authflavor)
{
	struct nfs_server	*server;
	struct inode		*root_inode;
	struct nfs_fattr	fattr;
	struct nfs_fsinfo	fsinfo = {
					.fattr = &fattr,
				};
	struct nfs_pathconf pathinfo = {
			.fattr = &fattr,
	};
	int no_root_error = 0;

	/* We probably want something more informative here */
	snprintf(sb->s_id, sizeof(sb->s_id), "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));

	server = NFS_SB(sb);

	sb->s_magic      = NFS_SUPER_MAGIC;

	root_inode = nfs_get_root(sb, &server->fh, &fsinfo);
	/* Did getting the root inode fail? */
	if (IS_ERR(root_inode)) {
		no_root_error = PTR_ERR(root_inode);
		goto out_no_root;
	}
	sb->s_root = d_alloc_root(root_inode);
	if (!sb->s_root) {
		no_root_error = -ENOMEM;
		goto out_no_root;
	}
	sb->s_root->d_op = server->rpc_ops->dentry_ops;

	/* Get some general file system info */
	if (server->namelen == 0 &&
	    server->rpc_ops->pathconf(server, &server->fh, &pathinfo) >= 0)
		server->namelen = pathinfo.max_namelen;
	/* Work out a lot of parameters */
	if (server->rsize == 0)
		server->rsize = nfs_block_size(fsinfo.rtpref, NULL);
	if (server->wsize == 0)
		server->wsize = nfs_block_size(fsinfo.wtpref, NULL);

	if (fsinfo.rtmax >= 512 && server->rsize > fsinfo.rtmax)
		server->rsize = nfs_block_size(fsinfo.rtmax, NULL);
	if (fsinfo.wtmax >= 512 && server->wsize > fsinfo.wtmax)
		server->wsize = nfs_block_size(fsinfo.wtmax, NULL);

	server->rpages = (server->rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
	if (server->rpages > NFS_READ_MAXIOV) {
		server->rpages = NFS_READ_MAXIOV;
		server->rsize = server->rpages << PAGE_CACHE_SHIFT;
	}

	server->wpages = (server->wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
        if (server->wpages > NFS_WRITE_MAXIOV) {
		server->wpages = NFS_WRITE_MAXIOV;
                server->wsize = server->wpages << PAGE_CACHE_SHIFT;
	}

	if (sb->s_blocksize == 0)
		sb->s_blocksize = nfs_block_bits(server->wsize,
							 &sb->s_blocksize_bits);
	server->wtmult = nfs_block_bits(fsinfo.wtmult, NULL);

	server->dtsize = nfs_block_size(fsinfo.dtpref, NULL);
	if (server->dtsize > PAGE_CACHE_SIZE)
		server->dtsize = PAGE_CACHE_SIZE;
	if (server->dtsize > server->rsize)
		server->dtsize = server->rsize;

	if (server->flags & NFS_MOUNT_NOAC) {
		server->acregmin = server->acregmax = 0;
		server->acdirmin = server->acdirmax = 0;
		sb->s_flags |= MS_SYNCHRONOUS;
	}
	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;

	sb->s_maxbytes = fsinfo.maxfilesize;
	if (sb->s_maxbytes > MAX_LFS_FILESIZE) 
		sb->s_maxbytes = MAX_LFS_FILESIZE; 

	/* We're airborne Set socket buffersize */
	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
	return 0;
	/* Yargs. It didn't work out. */
out_no_root:
	dprintk("nfs_sb_init: get root inode failed: errno %d\n", -no_root_error);
	if (!IS_ERR(root_inode))
		iput(root_inode);
	return no_root_error;
}

/*
 * Create an RPC client handle.
 */
static struct rpc_clnt *
nfs_create_client(struct nfs_server *server, const struct nfs_mount_data *data)
{
	struct rpc_timeout	timeparms;
	struct rpc_xprt		*xprt = NULL;
	struct rpc_clnt		*clnt = NULL;
	int			tcp   = (data->flags & NFS_MOUNT_TCP);

	/* Initialize timeout values */
	timeparms.to_initval = data->timeo * HZ / 10;
	timeparms.to_retries = data->retrans;
	timeparms.to_maxval  = tcp ? RPC_MAX_TCP_TIMEOUT : RPC_MAX_UDP_TIMEOUT;
	timeparms.to_exponential = 1;

	if (!timeparms.to_initval)
		timeparms.to_initval = (tcp ? 600 : 11) * HZ / 10;
	if (!timeparms.to_retries)
		timeparms.to_retries = 5;

	/* create transport and client */
	xprt = xprt_create_proto(tcp ? IPPROTO_TCP : IPPROTO_UDP,
				 &server->addr, &timeparms);
	if (IS_ERR(xprt)) {
		printk(KERN_WARNING "NFS: cannot create RPC transport.\n");
		return (struct rpc_clnt *)xprt;
	}
	clnt = rpc_create_client(xprt, server->hostname, &nfs_program,
				 server->rpc_ops->version, data->pseudoflavor);
	if (IS_ERR(clnt)) {
		printk(KERN_WARNING "NFS: cannot create RPC client.\n");
		goto out_fail;
	}

	clnt->cl_intr     = (server->flags & NFS_MOUNT_INTR) ? 1 : 0;
	clnt->cl_softrtry = (server->flags & NFS_MOUNT_SOFT) ? 1 : 0;
	clnt->cl_droppriv = (server->flags & NFS_MOUNT_BROKEN_SUID) ? 1 : 0;
	clnt->cl_chatty   = 1;

	return clnt;

out_fail:
	xprt_destroy(xprt);
	return clnt;
}

/*
 * The way this works is that the mount process passes a structure
 * in the data argument which contains the server's IP address
 * and the root file handle obtained from the server's mount
 * daemon. We stash these away in the private superblock fields.
 */
static int
nfs_fill_super(struct super_block *sb, struct nfs_mount_data *data, int silent)
{
	struct nfs_server	*server;
	rpc_authflavor_t	authflavor;

	server           = NFS_SB(sb);
	sb->s_blocksize_bits = 0;
	sb->s_blocksize = 0;
	if (data->bsize)
		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
	if (data->rsize)
		server->rsize = nfs_block_size(data->rsize, NULL);
	if (data->wsize)
		server->wsize = nfs_block_size(data->wsize, NULL);
	server->flags    = data->flags & NFS_MOUNT_FLAGMASK;

	server->acregmin = data->acregmin*HZ;
	server->acregmax = data->acregmax*HZ;
	server->acdirmin = data->acdirmin*HZ;
	server->acdirmax = data->acdirmax*HZ;

	/* Start lockd here, before we might error out */
	if (!(server->flags & NFS_MOUNT_NONLM))
		lockd_up();

	server->namelen  = data->namlen;
	server->hostname = kmalloc(strlen(data->hostname) + 1, GFP_KERNEL);
	if (!server->hostname)
		return -ENOMEM;
	strcpy(server->hostname, data->hostname);

	/* Check NFS protocol revision and initialize RPC op vector
	 * and file handle pool. */
	if (server->flags & NFS_MOUNT_VER3) {
#ifdef CONFIG_NFS_V3
		server->rpc_ops = &nfs_v3_clientops;
		server->caps |= NFS_CAP_READDIRPLUS;
		if (data->version < 4) {
			printk(KERN_NOTICE "NFS: NFSv3 not supported by mount program.\n");
			return -EIO;
		}
#else
		printk(KERN_NOTICE "NFS: NFSv3 not supported.\n");
		return -EIO;
#endif
	} else {
		server->rpc_ops = &nfs_v2_clientops;
	}

	/* Fill in pseudoflavor for mount version < 5 */
	if (!(data->flags & NFS_MOUNT_SECFLAVOUR))
		data->pseudoflavor = RPC_AUTH_UNIX;
	authflavor = data->pseudoflavor;	/* save for sb_init() */
	/* XXX maybe we want to add a server->pseudoflavor field */

	/* Create RPC client handles */
	server->client = nfs_create_client(server, data);
	if (IS_ERR(server->client))
		return PTR_ERR(server->client);
	/* RFC 2623, sec 2.3.2 */
	if (authflavor != RPC_AUTH_UNIX) {
		server->client_sys = rpc_clone_client(server->client);
		if (IS_ERR(server->client_sys))
			return PTR_ERR(server->client_sys);
		if (!rpcauth_create(RPC_AUTH_UNIX, server->client_sys))
			return -ENOMEM;
	} else {
		atomic_inc(&server->client->cl_count);
		server->client_sys = server->client;
	}

	if (server->flags & NFS_MOUNT_VER3) {
		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
			server->namelen = NFS3_MAXNAMLEN;
	} else {
		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
			server->namelen = NFS2_MAXNAMLEN;
	}

	sb->s_op = &nfs_sops;
	return nfs_sb_init(sb, authflavor);
}

static int
nfs_statfs(struct super_block *sb, struct kstatfs *buf)
{
	struct nfs_server *server = NFS_SB(sb);
	unsigned char blockbits;
	unsigned long blockres;
	struct nfs_fh *rootfh = NFS_FH(sb->s_root->d_inode);
	struct nfs_fattr fattr;
	struct nfs_fsstat res = {
			.fattr = &fattr,
	};
	int error;

	lock_kernel();

	error = server->rpc_ops->statfs(server, rootfh, &res);
	buf->f_type = NFS_SUPER_MAGIC;
	if (error < 0)
		goto out_err;