proc.c

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/*
 *  linux/fs/nfs/proc.c
 *
 *  Copyright (C) 1992, 1993, 1994  Rick Sladkey
 *
 *  OS-independent nfs remote procedure call functions
 *
 *  Tuned by Alan Cox <[e-mail]> for >3K buffers
 *  so at last we can have decent(ish) throughput off a 
 *  Sun server.
 *
 *  Coding optimized and cleaned up by Florian La Roche.
 *  Note: Error returns are optimized for NFS_OK, which isn't translated via
 *  nfs_stat_to_errno(), but happens to be already the right return code.
 *
 *  FixMe: We ought to define a sensible small max size for
 *  things like getattr that are tiny packets and use the
 *  old get_free_page stuff with it.
 *
 *  Also, the code currently doesn't check the size of the packet, when
 *  it decodes the packet.
 *
 *  Feel free to fix it and mail me the diffs if it worries you.
 */

/*
 * Defining NFS_PROC_DEBUG causes a lookup of a file named
 * "xyzzy" to toggle debugging.  Just cd to an NFS-mounted
 * filesystem and type 'ls xyzzy' to turn on debugging.
 */

#if 0
#define NFS_PROC_DEBUG
#endif

#include <linux/param.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/malloc.h>
#include <linux/nfs_fs.h>
#include <linux/utsname.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/in.h>
#include <linux/pagemap.h>

#include <asm/segment.h>

#ifdef NFS_PROC_DEBUG

static int proc_debug = 0;
#define PRINTK(format, args...) \
	do {						\
		if (proc_debug)				\
			printk(format , ## args);	\
	} while (0)

#else /* !NFS_PROC_DEBUG */

#define PRINTK(format, args...) do ; while (0)

#endif /* !NFS_PROC_DEBUG */

/* Mapping from NFS error code to "errno" error code. */
#define errno_NFSERR_IO EIO

static int *nfs_rpc_header(int *p, int procedure, int ruid);
static int *nfs_rpc_verify(int *p);
static int nfs_stat_to_errno(int stat);

/*
 * Our memory allocation and release functions.
 */
 
#define NFS_SLACK_SPACE		1024	/* Total overkill */ 
/* !!! Be careful, this constant is now also used in sock.c...
   We should easily convert to not using it anymore for most cases... */

static inline int *nfs_rpc_alloc(int size)
{
	int *i;

	while (!(i = (int *)kmalloc(size+NFS_SLACK_SPACE,GFP_NFS))) {
		schedule();
	}
	return i;
}

static inline void nfs_rpc_free(int *p)
{
	kfree((void *)p);
}

/*
 * Here are a bunch of xdr encode/decode functions that convert
 * between machine dependent and xdr data formats.
 */

#define QUADLEN(len) (((len) + 3) >> 2)

static inline int *xdr_encode_fhandle(int *p, struct nfs_fh *fhandle)
{
	*((struct nfs_fh *) p) = *fhandle;
	return p + QUADLEN(sizeof(*fhandle));
}

static inline int *xdr_decode_fhandle(int *p, struct nfs_fh *fhandle)
{
	*fhandle = *((struct nfs_fh *) p);
	return p + QUADLEN(sizeof(*fhandle));
}

static inline int *xdr_encode_string(int *p, const char *string)
{
	int len = strlen(string);
	int quadlen = QUADLEN(len);

	p[quadlen] = 0;
	*p++ = htonl(len);
	memcpy(p, string, len);
	return p + quadlen;
}

static inline int *xdr_decode_string(int *p, char *string, unsigned int maxlen)
{
	unsigned int len = ntohl(*p++);
	if (len > maxlen)
		return NULL;
	memcpy(string, p, len);
	string[len] = '\0';
	return p + QUADLEN(len);
}

static inline int *xdr_decode_string2(int *p, char **string, unsigned int *len,
			unsigned int maxlen)
{
	*len = ntohl(*p++);
	if (*len > maxlen)
		return NULL;
	*string = (char *) p;
	return p + QUADLEN(*len);
}


static inline int *xdr_encode_data(int *p, const char *data, int len)
{
	int quadlen = QUADLEN(len);
	
	p[quadlen] = 0;
	*p++ = htonl(len);
	memcpy_fromfs(p, data, len);
	return p + quadlen;
}

static inline int *xdr_decode_data(int *p, char *data, int *lenp, int maxlen)
{
	unsigned len = *lenp = ntohl(*p++);
	if (len > maxlen)
		return NULL;
	memcpy(data, p, len);
	return p + QUADLEN(len);
}

static int *xdr_decode_fattr(int *p, struct nfs_fattr *fattr)
{
	fattr->type = (enum nfs_ftype) ntohl(*p++);
	fattr->mode = ntohl(*p++);
	fattr->nlink = ntohl(*p++);
	fattr->uid = ntohl(*p++);
	fattr->gid = ntohl(*p++);
	fattr->size = ntohl(*p++);
	fattr->blocksize = ntohl(*p++);
	fattr->rdev = ntohl(*p++);
	fattr->blocks = ntohl(*p++);
	fattr->fsid = ntohl(*p++);
	fattr->fileid = ntohl(*p++);
	fattr->atime.seconds = ntohl(*p++);
	fattr->atime.useconds = ntohl(*p++);
	fattr->mtime.seconds = ntohl(*p++);
	fattr->mtime.useconds = ntohl(*p++);
	fattr->ctime.seconds = ntohl(*p++);
	fattr->ctime.useconds = ntohl(*p++);
	return p;
}

static int *xdr_encode_sattr(int *p, struct nfs_sattr *sattr)
{
	*p++ = htonl(sattr->mode);
	*p++ = htonl(sattr->uid);
	*p++ = htonl(sattr->gid);
	*p++ = htonl(sattr->size);
	*p++ = htonl(sattr->atime.seconds);
	*p++ = htonl(sattr->atime.useconds);
	*p++ = htonl(sattr->mtime.seconds);
	*p++ = htonl(sattr->mtime.useconds);
	return p;
}

static int *xdr_decode_entry(int *p, struct nfs_entry *entry)
{
	entry->fileid = ntohl(*p++);
	if (!(p = xdr_decode_string(p, entry->name, NFS_MAXNAMLEN)))
		return NULL;
	entry->cookie = ntohl(*p++);
	entry->eof = 0;
	return p;
}

static int *xdr_decode_fsinfo(int *p, struct nfs_fsinfo *res)
{
	res->tsize = ntohl(*p++);
	res->bsize = ntohl(*p++);
	res->blocks = ntohl(*p++);
	res->bfree = ntohl(*p++);
	res->bavail = ntohl(*p++);
	return p;
}

/*
 * One function for each procedure in the NFS protocol.
 */

int nfs_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
		     struct nfs_fattr *fattr)
{
	int *p, *p0;
	int status;
	int ruid = 0;

	PRINTK("NFS call  getattr\n");
	if (!(p0 = nfs_rpc_alloc(server->rsize)))
		return -EIO;
retry:
	p = nfs_rpc_header(p0, NFSPROC_GETATTR, ruid);
	p = xdr_encode_fhandle(p, fhandle);
	if ((status = nfs_rpc_call(server, p0, p, server->rsize)) < 0) {
		nfs_rpc_free(p0);
		return status;
	}
	if (!(p = nfs_rpc_verify(p0)))
		status = -errno_NFSERR_IO;
	else if ((status = ntohl(*p++)) == NFS_OK) {
		p = xdr_decode_fattr(p, fattr);
		PRINTK("NFS reply getattr\n");
		/* status = 0; */
	}
	else {
		if (!ruid && current->fsuid == 0 && current->uid != 0) {
			ruid = 1;
			goto retry;
		}
		PRINTK("NFS reply getattr failed = %d\n", status);
		status = -nfs_stat_to_errno(status);
	}
	nfs_rpc_free(p0);
	return status;
}

int nfs_proc_setattr(struct nfs_server *server, struct nfs_fh *fhandle,
		     struct nfs_sattr *sattr, struct nfs_fattr *fattr)
{
	int *p, *p0;
	int status;
	int ruid = 0;

	PRINTK("NFS call  setattr\n");
	if (!(p0 = nfs_rpc_alloc(server->wsize)))
		return -EIO;
retry:
	p = nfs_rpc_header(p0, NFSPROC_SETATTR, ruid);
	p = xdr_encode_fhandle(p, fhandle);
	p = xdr_encode_sattr(p, sattr);
	if ((status = nfs_rpc_call(server, p0, p, server->wsize)) < 0) {
		nfs_rpc_free(p0);
		return status;
	}
	if (!(p = nfs_rpc_verify(p0)))
		status = -errno_NFSERR_IO;
	else if ((status = ntohl(*p++)) == NFS_OK) {
		p = xdr_decode_fattr(p, fattr);
		PRINTK("NFS reply setattr\n");
		/* status = 0; */
	}
	else {
		if (!ruid && current->fsuid == 0 && current->uid != 0) {
			ruid = 1;
			goto retry;
		}
		PRINTK("NFS reply setattr failed = %d\n", status);
		status = -nfs_stat_to_errno(status);
	}
	nfs_rpc_free(p0);
	return status;
}

int nfs_proc_lookup(struct nfs_server *server, struct nfs_fh *dir, const char *name,
		    struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
	int *p, *p0;
	int status;
	int ruid = 0;

	PRINTK("NFS call  lookup %s\n", name);
#ifdef NFS_PROC_DEBUG
	if (!strcmp(name, "xyzzy"))
		proc_debug = 1 - proc_debug;
#endif
	if (!(p0 = nfs_rpc_alloc(server->rsize)))
		return -EIO;
retry:
	p = nfs_rpc_header(p0, NFSPROC_LOOKUP, ruid);
	p = xdr_encode_fhandle(p, dir);
	p = xdr_encode_string(p, name);
	if ((status = nfs_rpc_call(server, p0, p, server->rsize)) < 0) {
		nfs_rpc_free(p0);
		return status;
	}
	if (!(p = nfs_rpc_verify(p0)))
		status = -errno_NFSERR_IO;
	else if ((status = ntohl(*p++)) == NFS_OK) {
		p = xdr_decode_fhandle(p, fhandle);
		p = xdr_decode_fattr(p, fattr);
		PRINTK("NFS reply lookup\n");
		/* status = 0; */
	}
	else {
		if (!ruid && current->fsuid == 0 && current->uid != 0) {
			ruid = 1;
			goto retry;
		}
		PRINTK("NFS reply lookup failed = %d\n", status);
		status = -nfs_stat_to_errno(status);
	}
	nfs_rpc_free(p0);
	return status;
}

int nfs_proc_readlink(struct nfs_server *server, struct nfs_fh *fhandle,
		int **p0, char **string, unsigned int *len, unsigned int maxlen)
{
	int *p;
	int status, ruid = 0;

	PRINTK("NFS call  readlink\n");
	if (!(*p0 = nfs_rpc_alloc(server->rsize)))
		return -EIO;
retry:
	p = nfs_rpc_header(*p0, NFSPROC_READLINK, ruid);
	p = xdr_encode_fhandle(p, fhandle);
	if ((status = nfs_rpc_call(server, *p0, p, server->rsize)) < 0)
		return status;
	if (!(p = nfs_rpc_verify(*p0)))
		status = -errno_NFSERR_IO;
	else if ((status = ntohl(*p++)) == NFS_OK) {
		if (!(p = xdr_decode_string2(p, string, len, maxlen))) {
			printk("nfs_proc_readlink: giant pathname\n");
			status = -errno_NFSERR_IO;
		}
		else	/* status = 0, */
			PRINTK("NFS reply readlink\n");
	}
	else {
		if (!ruid && current->fsuid == 0 && current->uid != 0) {
			ruid = 1;
			goto retry;
		}
		PRINTK("NFS reply readlink failed = %d\n", status);
		status = -nfs_stat_to_errno(status);
	}
	return status;
}

int nfs_proc_read(struct nfs_server *server, struct nfs_fh *fhandle,
	  int offset, int count, char *data, struct nfs_fattr *fattr)
{
	int *p, *p0;
	int status;
	int ruid = 0;
	int len;

	PRINTK("NFS call  read %d @ %d\n", count, offset);
	if (!(p0 = nfs_rpc_alloc(server->rsize)))
		return -EIO;
retry:
	p = nfs_rpc_header(p0, NFSPROC_READ, ruid);
	p = xdr_encode_fhandle(p, fhandle);
	*p++ = htonl(offset);
	*p++ = htonl(count);
	*p++ = htonl(count); /* traditional, could be any value */
	if ((status = nfs_rpc_call(server, p0, p, server->rsize)) < 0) {
		nfs_rpc_free(p0);
		return status;
	}
	if (!(p = nfs_rpc_verify(p0)))
		status = -errno_NFSERR_IO;
	else if ((status = ntohl(*p++)) == NFS_OK) {
		p = xdr_decode_fattr(p, fattr);
		if (!(p = xdr_decode_data(p, data, &len, count))) {
			printk("nfs_proc_read: giant data size\n"); 
			status = -errno_NFSERR_IO;
		}
		else {
			status = len;
			PRINTK("NFS reply read %d\n", len);
		}
	}
	else {
		if (!ruid && current->fsuid == 0 && current->uid != 0) {
			ruid = 1;
			goto retry;
		}
		PRINTK("NFS reply read failed = %d\n", status);
		status = -nfs_stat_to_errno(status);
	}
	nfs_rpc_free(p0);
	return status;
}

int
nfs_proc_read_request(struct rpc_ioreq *req, struct nfs_server *server,
			struct nfs_fh *fh, unsigned long offset,
			unsigned long count, __u32 *buf)
{
	__u32	*p, *p0;
	int	len;

	PRINTK("NFS reqst read %ld @ %ld\n", count, offset);
	if (!(p0 = nfs_rpc_alloc(NFS_SLACK_SPACE)))
		return -EIO;

	p = nfs_rpc_header(p0, NFSPROC_READ, 0);
	p = xdr_encode_fhandle(p, fh);
	*p++ = htonl(offset);
	*p++ = htonl(count);
	*p++ = htonl(count); /* traditional, could be any value */
	req->rq_svec[0].iov_base = p0;
	req->rq_svec[0].iov_len  = (p - p0) << 2;
	req->rq_slen = (p - p0) << 2;
	req->rq_snr = 1;

	len = (6 + 1 + 17 + 1);		/* standard READ reply header */
	req->rq_rvec[0].iov_base = p0;
	req->rq_rvec[0].iov_len  = len << 2;
	req->rq_rvec[1].iov_base = buf;
	req->rq_rvec[1].iov_len  = count;
	req->rq_rvec[2].iov_base = p0 + len;		/* spill buffer */
	req->rq_rvec[2].iov_len  = (NFS_SLACK_SPACE - len) << 2;
	req->rq_rlen = count + NFS_SLACK_SPACE;
	req->rq_rnr = 3;

	req->rq_addr = &server->toaddr;
	req->rq_alen = sizeof(server->toaddr);

	return rpc_transmit(server->rsock, req);
}

int
nfs_proc_read_reply(struct rpc_ioreq *req, struct nfs_fattr *fattr)
{
	int		status;
	__u32		*p0, *p;
	int		count;

	p0 = (__u32 *) req->rq_rvec[0].iov_base;

	if (!(p = nfs_rpc_verify(p0))) {
		/* Tell the upper layers to retry */
		status = -EAGAIN;
		/* status = -errno_NFSERR_IO; */
	} else if ((status = ntohl(*p++)) == NFS_OK) {
		p = xdr_decode_fattr(p, fattr);
		count = ntohl(*p++);
		if (p != req->rq_rvec[2].iov_base) {
			/* unexpected RPC reply header size. punt.
			 * fixme: move iovec contents to align data
			 * on page boundary and adjust RPC header size
			 * guess. */
			status = -errno_NFSERR_IO;
			PRINTK("NFS reply read odd header size %d\n",
					(p - p0) << 2);
		} else {
			status = count;
			PRINTK("NFS reply read %d\n", count);
		}
	}
	else {
		PRINTK("NFS reply read failed = %d\n", status);
		status = -nfs_stat_to_errno(status);
	}
	nfs_rpc_free(p0);
	return status;
}

int nfs_proc_write(struct inode * inode, int offset,
		   int count, const char *data, struct nfs_fattr *fattr)
{
	int *p, *p0;
	int status;
	int ruid = 0;
	void * kdata;	/* address of kernel copy */
	struct nfs_server * server = NFS_SERVER(inode);
	struct nfs_fh *fhandle = NFS_FH(inode);

	PRINTK("NFS call  write %d @ %d\n", count, offset);
	if (!(p0 = nfs_rpc_alloc(server->wsize)))
		return -EIO;
retry:
	p = nfs_rpc_header(p0, NFSPROC_WRITE, ruid);
	p = xdr_encode_fhandle(p, fhandle);
	*p++ = htonl(offset); /* traditional, could be any value */
	*p++ = htonl(offset);
	*p++ = htonl(count); /* traditional, could be any value */
	kdata = (void *) (p+1);	/* start of data in RPC buffer */
	p = xdr_encode_data(p, data, count);
	if ((status = nfs_rpc_call(server, p0, p, server->wsize)) < 0) {
		nfs_rpc_free(p0);
		return status;
	}