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linux-stable/net/9p/protocol.c
Sripathi Kodi 7751bdb3a0 9p: readdir implementation for 9p2000.L 
This patch implements the kernel part of readdir() implementation for 9p2000.L

    Change from V3: Instead of inode, server now sends qids for each dirent

    SYNOPSIS

    size[4] Treaddir tag[2] fid[4] offset[8] count[4]
    size[4] Rreaddir tag[2] count[4] data[count]

    DESCRIPTION

    The readdir request asks the server to read the directory specified by 'fid'
    at an offset specified by 'offset' and return as many dirent structures as
    possible that fit into count bytes. Each dirent structure is laid out as
    follows.

            qid.type[1]
              the type of the file (directory, etc.), represented as a bit
              vector corresponding to the high 8 bits of the file's mode
              word.

            qid.vers[4]
              version number for given path

            qid.path[8]
              the file server's unique identification for the file

            offset[8]
              offset into the next dirent.

            type[1]
              type of this directory entry.

            name[256]
              name of this directory entry.

    This patch adds v9fs_dir_readdir_dotl() as the readdir() call for 9p2000.L.
    This function sends P9_TREADDIR command to the server. In response the server
    sends a buffer filled with dirent structures. This is different from the
    existing v9fs_dir_readdir() call which receives stat structures from the server.
    This results in significant speedup of readdir() on large directories.
    For example, doing 'ls >/dev/null' on a directory with 10000 files on my
    laptop takes 1.088 seconds with the existing code, but only takes 0.339 seconds
    with the new readdir.

Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2010-08-02 14:25:07 -05:00

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/*
* net/9p/protocol.c
*
* 9P Protocol Support Code
*
* Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
*
* Base on code from Anthony Liguori <aliguori@us.ibm.com>
* Copyright (C) 2008 by IBM, Corp.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "protocol.h"
#ifndef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#endif
#ifndef MAX
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
#endif
#ifndef offset_of
#define offset_of(type, memb) \
((unsigned long)(&((type *)0)->memb))
#endif
#ifndef container_of
#define container_of(obj, type, memb) \
((type *)(((char *)obj) - offset_of(type, memb)))
#endif
static int
p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
#ifdef CONFIG_NET_9P_DEBUG
void
p9pdu_dump(int way, struct p9_fcall *pdu)
{
int i, n;
u8 *data = pdu->sdata;
int datalen = pdu->size;
char buf[255];
int buflen = 255;
i = n = 0;
if (datalen > (buflen-16))
datalen = buflen-16;
while (i < datalen) {
n += scnprintf(buf + n, buflen - n, "%02x ", data[i]);
if (i%4 == 3)
n += scnprintf(buf + n, buflen - n, " ");
if (i%32 == 31)
n += scnprintf(buf + n, buflen - n, "\n");
i++;
}
n += scnprintf(buf + n, buflen - n, "\n");
if (way)
P9_DPRINTK(P9_DEBUG_PKT, "[[[(%d) %s\n", datalen, buf);
else
P9_DPRINTK(P9_DEBUG_PKT, "]]](%d) %s\n", datalen, buf);
}
#else
void
p9pdu_dump(int way, struct p9_fcall *pdu)
{
}
#endif
EXPORT_SYMBOL(p9pdu_dump);
void p9stat_free(struct p9_wstat *stbuf)
{
kfree(stbuf->name);
kfree(stbuf->uid);
kfree(stbuf->gid);
kfree(stbuf->muid);
kfree(stbuf->extension);
}
EXPORT_SYMBOL(p9stat_free);
static size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
{
size_t len = MIN(pdu->size - pdu->offset, size);
memcpy(data, &pdu->sdata[pdu->offset], len);
pdu->offset += len;
return size - len;
}
static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
{
size_t len = MIN(pdu->capacity - pdu->size, size);
memcpy(&pdu->sdata[pdu->size], data, len);
pdu->size += len;
return size - len;
}
static size_t
pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
{
size_t len = MIN(pdu->capacity - pdu->size, size);
int err = copy_from_user(&pdu->sdata[pdu->size], udata, len);
if (err)
printk(KERN_WARNING "pdu_write_u returning: %d\n", err);
pdu->size += len;
return size - len;
}
/*
b - int8_t
w - int16_t
d - int32_t
q - int64_t
s - string
S - stat
Q - qid
D - data blob (int32_t size followed by void *, results are not freed)
T - array of strings (int16_t count, followed by strings)
R - array of qids (int16_t count, followed by qids)
? - if optional = 1, continue parsing
*/
static int
p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
va_list ap)
{
const char *ptr;
int errcode = 0;
for (ptr = fmt; *ptr; ptr++) {
switch (*ptr) {
case 'b':{
int8_t *val = va_arg(ap, int8_t *);
if (pdu_read(pdu, val, sizeof(*val))) {
errcode = -EFAULT;
break;
}
}
break;
case 'w':{
int16_t *val = va_arg(ap, int16_t *);
__le16 le_val;
if (pdu_read(pdu, &le_val, sizeof(le_val))) {
errcode = -EFAULT;
break;
}
*val = le16_to_cpu(le_val);
}
break;
case 'd':{
int32_t *val = va_arg(ap, int32_t *);
__le32 le_val;
if (pdu_read(pdu, &le_val, sizeof(le_val))) {
errcode = -EFAULT;
break;
}
*val = le32_to_cpu(le_val);
}
break;
case 'q':{
int64_t *val = va_arg(ap, int64_t *);
__le64 le_val;
if (pdu_read(pdu, &le_val, sizeof(le_val))) {
errcode = -EFAULT;
break;
}
*val = le64_to_cpu(le_val);
}
break;
case 's':{
char **sptr = va_arg(ap, char **);
int16_t len;
int size;
errcode = p9pdu_readf(pdu, proto_version,
"w", &len);
if (errcode)
break;
size = MAX(len, 0);
*sptr = kmalloc(size + 1, GFP_KERNEL);
if (*sptr == NULL) {
errcode = -EFAULT;
break;
}
if (pdu_read(pdu, *sptr, size)) {
errcode = -EFAULT;
kfree(*sptr);
*sptr = NULL;
} else
(*sptr)[size] = 0;
}
break;
case 'Q':{
struct p9_qid *qid =
va_arg(ap, struct p9_qid *);
errcode = p9pdu_readf(pdu, proto_version, "bdq",
&qid->type, &qid->version,
&qid->path);
}
break;
case 'S':{
struct p9_wstat *stbuf =
va_arg(ap, struct p9_wstat *);
memset(stbuf, 0, sizeof(struct p9_wstat));
stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
-1;
errcode =
p9pdu_readf(pdu, proto_version,
"wwdQdddqssss?sddd",
&stbuf->size, &stbuf->type,
&stbuf->dev, &stbuf->qid,
&stbuf->mode, &stbuf->atime,
&stbuf->mtime, &stbuf->length,
&stbuf->name, &stbuf->uid,
&stbuf->gid, &stbuf->muid,
&stbuf->extension,
&stbuf->n_uid, &stbuf->n_gid,
&stbuf->n_muid);
if (errcode)
p9stat_free(stbuf);
}
break;
case 'D':{
int32_t *count = va_arg(ap, int32_t *);
void **data = va_arg(ap, void **);
errcode =
p9pdu_readf(pdu, proto_version, "d", count);
if (!errcode) {
*count =
MIN(*count,
pdu->size - pdu->offset);
*data = &pdu->sdata[pdu->offset];
}
}
break;
case 'T':{
int16_t *nwname = va_arg(ap, int16_t *);
char ***wnames = va_arg(ap, char ***);
errcode = p9pdu_readf(pdu, proto_version,
"w", nwname);
if (!errcode) {
*wnames =
kmalloc(sizeof(char *) * *nwname,
GFP_KERNEL);
if (!*wnames)
errcode = -ENOMEM;
}
if (!errcode) {
int i;
for (i = 0; i < *nwname; i++) {
errcode =
p9pdu_readf(pdu,
proto_version,
"s",
&(*wnames)[i]);
if (errcode)
break;
}
}
if (errcode) {
if (*wnames) {
int i;
for (i = 0; i < *nwname; i++)
kfree((*wnames)[i]);
}
kfree(*wnames);
*wnames = NULL;
}
}
break;
case 'R':{
int16_t *nwqid = va_arg(ap, int16_t *);
struct p9_qid **wqids =
va_arg(ap, struct p9_qid **);
*wqids = NULL;
errcode =
p9pdu_readf(pdu, proto_version, "w", nwqid);
if (!errcode) {
*wqids =
kmalloc(*nwqid *
sizeof(struct p9_qid),
GFP_KERNEL);
if (*wqids == NULL)
errcode = -ENOMEM;
}
if (!errcode) {
int i;
for (i = 0; i < *nwqid; i++) {
errcode =
p9pdu_readf(pdu,
proto_version,
"Q",
&(*wqids)[i]);
if (errcode)
break;
}
}
if (errcode) {
kfree(*wqids);
*wqids = NULL;
}
}
break;
case '?':
if ((proto_version != p9_proto_2000u) &&
(proto_version != p9_proto_2000L))
return 0;
break;
default:
BUG();
break;
}
if (errcode)
break;
}
return errcode;
}
int
p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
va_list ap)
{
const char *ptr;
int errcode = 0;
for (ptr = fmt; *ptr; ptr++) {
switch (*ptr) {
case 'b':{
int8_t val = va_arg(ap, int);
if (pdu_write(pdu, &val, sizeof(val)))
errcode = -EFAULT;
}
break;
case 'w':{
__le16 val = cpu_to_le16(va_arg(ap, int));
if (pdu_write(pdu, &val, sizeof(val)))
errcode = -EFAULT;
}
break;
case 'd':{
__le32 val = cpu_to_le32(va_arg(ap, int32_t));
if (pdu_write(pdu, &val, sizeof(val)))
errcode = -EFAULT;
}
break;
case 'q':{
__le64 val = cpu_to_le64(va_arg(ap, int64_t));
if (pdu_write(pdu, &val, sizeof(val)))
errcode = -EFAULT;
}
break;
case 's':{
const char *sptr = va_arg(ap, const char *);
int16_t len = 0;
if (sptr)
len = MIN(strlen(sptr), USHRT_MAX);
errcode = p9pdu_writef(pdu, proto_version,
"w", len);
if (!errcode && pdu_write(pdu, sptr, len))
errcode = -EFAULT;
}
break;
case 'Q':{
const struct p9_qid *qid =
va_arg(ap, const struct p9_qid *);
errcode =
p9pdu_writef(pdu, proto_version, "bdq",
qid->type, qid->version,
qid->path);
} break;
case 'S':{
const struct p9_wstat *stbuf =
va_arg(ap, const struct p9_wstat *);
errcode =
p9pdu_writef(pdu, proto_version,
"wwdQdddqssss?sddd",
stbuf->size, stbuf->type,
stbuf->dev, &stbuf->qid,
stbuf->mode, stbuf->atime,
stbuf->mtime, stbuf->length,
stbuf->name, stbuf->uid,
stbuf->gid, stbuf->muid,
stbuf->extension, stbuf->n_uid,
stbuf->n_gid, stbuf->n_muid);
} break;
case 'D':{
int32_t count = va_arg(ap, int32_t);
const void *data = va_arg(ap, const void *);
errcode = p9pdu_writef(pdu, proto_version, "d",
count);
if (!errcode && pdu_write(pdu, data, count))
errcode = -EFAULT;
}
break;
case 'U':{
int32_t count = va_arg(ap, int32_t);
const char __user *udata =
va_arg(ap, const void __user *);
errcode = p9pdu_writef(pdu, proto_version, "d",
count);
if (!errcode && pdu_write_u(pdu, udata, count))
errcode = -EFAULT;
}
break;
case 'T':{
int16_t nwname = va_arg(ap, int);
const char **wnames = va_arg(ap, const char **);
errcode = p9pdu_writef(pdu, proto_version, "w",
nwname);
if (!errcode) {
int i;
for (i = 0; i < nwname; i++) {
errcode =
p9pdu_writef(pdu,
proto_version,
"s",
wnames[i]);
if (errcode)
break;
}
}
}
break;
case 'R':{
int16_t nwqid = va_arg(ap, int);
struct p9_qid *wqids =
va_arg(ap, struct p9_qid *);
errcode = p9pdu_writef(pdu, proto_version, "w",
nwqid);
if (!errcode) {
int i;
for (i = 0; i < nwqid; i++) {
errcode =
p9pdu_writef(pdu,
proto_version,
"Q",
&wqids[i]);
if (errcode)
break;
}
}
}
break;
case '?':
if ((proto_version != p9_proto_2000u) &&
(proto_version != p9_proto_2000L))
return 0;
break;
default:
BUG();
break;
}
if (errcode)
break;
}
return errcode;
}
int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
va_end(ap);
return ret;
}
static int
p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
va_end(ap);
return ret;
}
int p9stat_read(char *buf, int len, struct p9_wstat *st, int proto_version)
{
struct p9_fcall fake_pdu;
int ret;
fake_pdu.size = len;
fake_pdu.capacity = len;
fake_pdu.sdata = buf;
fake_pdu.offset = 0;
ret = p9pdu_readf(&fake_pdu, proto_version, "S", st);
if (ret) {
P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
p9pdu_dump(1, &fake_pdu);
}
return ret;
}
EXPORT_SYMBOL(p9stat_read);
int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
{
return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
}
int p9pdu_finalize(struct p9_fcall *pdu)
{
int size = pdu->size;
int err;
pdu->size = 0;
err = p9pdu_writef(pdu, 0, "d", size);
pdu->size = size;
#ifdef CONFIG_NET_9P_DEBUG
if ((p9_debug_level & P9_DEBUG_PKT) == P9_DEBUG_PKT)
p9pdu_dump(0, pdu);
#endif
P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
pdu->id, pdu->tag);
return err;
}
void p9pdu_reset(struct p9_fcall *pdu)
{
pdu->offset = 0;
pdu->size = 0;
}
int p9dirent_read(char *buf, int len, struct p9_dirent *dirent,
int proto_version)
{
struct p9_fcall fake_pdu;
int ret;
char *nameptr;
fake_pdu.size = len;
fake_pdu.capacity = len;
fake_pdu.sdata = buf;
fake_pdu.offset = 0;
ret = p9pdu_readf(&fake_pdu, proto_version, "Qqbs", &dirent->qid,
&dirent->d_off, &dirent->d_type, &nameptr);
if (ret) {
P9_DPRINTK(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
p9pdu_dump(1, &fake_pdu);
goto out;
}
strcpy(dirent->d_name, nameptr);
out:
return fake_pdu.offset;
}
EXPORT_SYMBOL(p9dirent_read);
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