linux/fs/9p/vfs_inode.c
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   1/*
   2 *  linux/fs/9p/vfs_inode.c
   3 *
   4 * This file contains vfs inode ops for the 9P2000 protocol.
   5 *
   6 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8 *
   9 *  This program is free software; you can redistribute it and/or modify
  10 *  it under the terms of the GNU General Public License version 2
  11 *  as published by the Free Software Foundation.
  12 *
  13 *  This program is distributed in the hope that it will be useful,
  14 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 *  GNU General Public License for more details.
  17 *
  18 *  You should have received a copy of the GNU General Public License
  19 *  along with this program; if not, write to:
  20 *  Free Software Foundation
  21 *  51 Franklin Street, Fifth Floor
  22 *  Boston, MA  02111-1301  USA
  23 *
  24 */
  25
  26#include <linux/module.h>
  27#include <linux/errno.h>
  28#include <linux/fs.h>
  29#include <linux/file.h>
  30#include <linux/pagemap.h>
  31#include <linux/stat.h>
  32#include <linux/string.h>
  33#include <linux/inet.h>
  34#include <linux/namei.h>
  35#include <linux/idr.h>
  36#include <linux/sched.h>
  37#include <net/9p/9p.h>
  38#include <net/9p/client.h>
  39
  40#include "v9fs.h"
  41#include "v9fs_vfs.h"
  42#include "fid.h"
  43#include "cache.h"
  44
  45static const struct inode_operations v9fs_dir_inode_operations;
  46static const struct inode_operations v9fs_dir_inode_operations_ext;
  47static const struct inode_operations v9fs_file_inode_operations;
  48static const struct inode_operations v9fs_symlink_inode_operations;
  49
  50/**
  51 * unixmode2p9mode - convert unix mode bits to plan 9
  52 * @v9ses: v9fs session information
  53 * @mode: mode to convert
  54 *
  55 */
  56
  57static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
  58{
  59        int res;
  60        res = mode & 0777;
  61        if (S_ISDIR(mode))
  62                res |= P9_DMDIR;
  63        if (v9fs_extended(v9ses)) {
  64                if (S_ISLNK(mode))
  65                        res |= P9_DMSYMLINK;
  66                if (v9ses->nodev == 0) {
  67                        if (S_ISSOCK(mode))
  68                                res |= P9_DMSOCKET;
  69                        if (S_ISFIFO(mode))
  70                                res |= P9_DMNAMEDPIPE;
  71                        if (S_ISBLK(mode))
  72                                res |= P9_DMDEVICE;
  73                        if (S_ISCHR(mode))
  74                                res |= P9_DMDEVICE;
  75                }
  76
  77                if ((mode & S_ISUID) == S_ISUID)
  78                        res |= P9_DMSETUID;
  79                if ((mode & S_ISGID) == S_ISGID)
  80                        res |= P9_DMSETGID;
  81                if ((mode & S_ISVTX) == S_ISVTX)
  82                        res |= P9_DMSETVTX;
  83                if ((mode & P9_DMLINK))
  84                        res |= P9_DMLINK;
  85        }
  86
  87        return res;
  88}
  89
  90/**
  91 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
  92 * @v9ses: v9fs session information
  93 * @mode: mode to convert
  94 *
  95 */
  96
  97static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
  98{
  99        int res;
 100
 101        res = mode & 0777;
 102
 103        if ((mode & P9_DMDIR) == P9_DMDIR)
 104                res |= S_IFDIR;
 105        else if ((mode & P9_DMSYMLINK) && (v9fs_extended(v9ses)))
 106                res |= S_IFLNK;
 107        else if ((mode & P9_DMSOCKET) && (v9fs_extended(v9ses))
 108                 && (v9ses->nodev == 0))
 109                res |= S_IFSOCK;
 110        else if ((mode & P9_DMNAMEDPIPE) && (v9fs_extended(v9ses))
 111                 && (v9ses->nodev == 0))
 112                res |= S_IFIFO;
 113        else if ((mode & P9_DMDEVICE) && (v9fs_extended(v9ses))
 114                 && (v9ses->nodev == 0))
 115                res |= S_IFBLK;
 116        else
 117                res |= S_IFREG;
 118
 119        if (v9fs_extended(v9ses)) {
 120                if ((mode & P9_DMSETUID) == P9_DMSETUID)
 121                        res |= S_ISUID;
 122
 123                if ((mode & P9_DMSETGID) == P9_DMSETGID)
 124                        res |= S_ISGID;
 125
 126                if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
 127                        res |= S_ISVTX;
 128        }
 129
 130        return res;
 131}
 132
 133/**
 134 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 135 * @uflags: flags to convert
 136 * @extended: if .u extensions are active
 137 */
 138
 139int v9fs_uflags2omode(int uflags, int extended)
 140{
 141        int ret;
 142
 143        ret = 0;
 144        switch (uflags&3) {
 145        default:
 146        case O_RDONLY:
 147                ret = P9_OREAD;
 148                break;
 149
 150        case O_WRONLY:
 151                ret = P9_OWRITE;
 152                break;
 153
 154        case O_RDWR:
 155                ret = P9_ORDWR;
 156                break;
 157        }
 158
 159        if (uflags & O_TRUNC)
 160                ret |= P9_OTRUNC;
 161
 162        if (extended) {
 163                if (uflags & O_EXCL)
 164                        ret |= P9_OEXCL;
 165
 166                if (uflags & O_APPEND)
 167                        ret |= P9_OAPPEND;
 168        }
 169
 170        return ret;
 171}
 172
 173/**
 174 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 175 * @wstat: structure to initialize
 176 *
 177 */
 178
 179static void
 180v9fs_blank_wstat(struct p9_wstat *wstat)
 181{
 182        wstat->type = ~0;
 183        wstat->dev = ~0;
 184        wstat->qid.type = ~0;
 185        wstat->qid.version = ~0;
 186        *((long long *)&wstat->qid.path) = ~0;
 187        wstat->mode = ~0;
 188        wstat->atime = ~0;
 189        wstat->mtime = ~0;
 190        wstat->length = ~0;
 191        wstat->name = NULL;
 192        wstat->uid = NULL;
 193        wstat->gid = NULL;
 194        wstat->muid = NULL;
 195        wstat->n_uid = ~0;
 196        wstat->n_gid = ~0;
 197        wstat->n_muid = ~0;
 198        wstat->extension = NULL;
 199}
 200
 201#ifdef CONFIG_9P_FSCACHE
 202/**
 203 * v9fs_alloc_inode - helper function to allocate an inode
 204 * This callback is executed before setting up the inode so that we
 205 * can associate a vcookie with each inode.
 206 *
 207 */
 208
 209struct inode *v9fs_alloc_inode(struct super_block *sb)
 210{
 211        struct v9fs_cookie *vcookie;
 212        vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
 213                                                         GFP_KERNEL);
 214        if (!vcookie)
 215                return NULL;
 216
 217        vcookie->fscache = NULL;
 218        vcookie->qid = NULL;
 219        spin_lock_init(&vcookie->lock);
 220        return &vcookie->inode;
 221}
 222
 223/**
 224 * v9fs_destroy_inode - destroy an inode
 225 *
 226 */
 227
 228void v9fs_destroy_inode(struct inode *inode)
 229{
 230        kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
 231}
 232#endif
 233
 234/**
 235 * v9fs_get_inode - helper function to setup an inode
 236 * @sb: superblock
 237 * @mode: mode to setup inode with
 238 *
 239 */
 240
 241struct inode *v9fs_get_inode(struct super_block *sb, int mode)
 242{
 243        int err;
 244        struct inode *inode;
 245        struct v9fs_session_info *v9ses = sb->s_fs_info;
 246
 247        P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
 248
 249        inode = new_inode(sb);
 250        if (!inode) {
 251                P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
 252                return ERR_PTR(-ENOMEM);
 253        }
 254
 255        inode->i_mode = mode;
 256        inode->i_uid = current_fsuid();
 257        inode->i_gid = current_fsgid();
 258        inode->i_blocks = 0;
 259        inode->i_rdev = 0;
 260        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 261        inode->i_mapping->a_ops = &v9fs_addr_operations;
 262
 263        switch (mode & S_IFMT) {
 264        case S_IFIFO:
 265        case S_IFBLK:
 266        case S_IFCHR:
 267        case S_IFSOCK:
 268                if (!v9fs_extended(v9ses)) {
 269                        P9_DPRINTK(P9_DEBUG_ERROR,
 270                                   "special files without extended mode\n");
 271                        err = -EINVAL;
 272                        goto error;
 273                }
 274                init_special_inode(inode, inode->i_mode, inode->i_rdev);
 275                break;
 276        case S_IFREG:
 277                inode->i_op = &v9fs_file_inode_operations;
 278                inode->i_fop = &v9fs_file_operations;
 279                break;
 280        case S_IFLNK:
 281                if (!v9fs_extended(v9ses)) {
 282                        P9_DPRINTK(P9_DEBUG_ERROR,
 283                                   "extended modes used w/o 9P2000.u\n");
 284                        err = -EINVAL;
 285                        goto error;
 286                }
 287                inode->i_op = &v9fs_symlink_inode_operations;
 288                break;
 289        case S_IFDIR:
 290                inc_nlink(inode);
 291                if (v9fs_extended(v9ses))
 292                        inode->i_op = &v9fs_dir_inode_operations_ext;
 293                else
 294                        inode->i_op = &v9fs_dir_inode_operations;
 295                inode->i_fop = &v9fs_dir_operations;
 296                break;
 297        default:
 298                P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
 299                           mode, mode & S_IFMT);
 300                err = -EINVAL;
 301                goto error;
 302        }
 303
 304        return inode;
 305
 306error:
 307        iput(inode);
 308        return ERR_PTR(err);
 309}
 310
 311/*
 312static struct v9fs_fid*
 313v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 314{
 315        int err;
 316        int nfid;
 317        struct v9fs_fid *ret;
 318        struct v9fs_fcall *fcall;
 319
 320        nfid = v9fs_get_idpool(&v9ses->fidpool);
 321        if (nfid < 0) {
 322                eprintk(KERN_WARNING, "no free fids available\n");
 323                return ERR_PTR(-ENOSPC);
 324        }
 325
 326        err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 327                &fcall);
 328
 329        if (err < 0) {
 330                if (fcall && fcall->id == RWALK)
 331                        goto clunk_fid;
 332
 333                PRINT_FCALL_ERROR("walk error", fcall);
 334                v9fs_put_idpool(nfid, &v9ses->fidpool);
 335                goto error;
 336        }
 337
 338        kfree(fcall);
 339        fcall = NULL;
 340        ret = v9fs_fid_create(v9ses, nfid);
 341        if (!ret) {
 342                err = -ENOMEM;
 343                goto clunk_fid;
 344        }
 345
 346        err = v9fs_fid_insert(ret, dentry);
 347        if (err < 0) {
 348                v9fs_fid_destroy(ret);
 349                goto clunk_fid;
 350        }
 351
 352        return ret;
 353
 354clunk_fid:
 355        v9fs_t_clunk(v9ses, nfid);
 356
 357error:
 358        kfree(fcall);
 359        return ERR_PTR(err);
 360}
 361*/
 362
 363
 364/**
 365 * v9fs_clear_inode - release an inode
 366 * @inode: inode to release
 367 *
 368 */
 369void v9fs_clear_inode(struct inode *inode)
 370{
 371        filemap_fdatawrite(inode->i_mapping);
 372
 373#ifdef CONFIG_9P_FSCACHE
 374        v9fs_cache_inode_put_cookie(inode);
 375#endif
 376}
 377
 378/**
 379 * v9fs_inode_from_fid - populate an inode by issuing a attribute request
 380 * @v9ses: session information
 381 * @fid: fid to issue attribute request for
 382 * @sb: superblock on which to create inode
 383 *
 384 */
 385
 386static struct inode *
 387v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 388        struct super_block *sb)
 389{
 390        int err, umode;
 391        struct inode *ret;
 392        struct p9_wstat *st;
 393
 394        ret = NULL;
 395        st = p9_client_stat(fid);
 396        if (IS_ERR(st))
 397                return ERR_CAST(st);
 398
 399        umode = p9mode2unixmode(v9ses, st->mode);
 400        ret = v9fs_get_inode(sb, umode);
 401        if (IS_ERR(ret)) {
 402                err = PTR_ERR(ret);
 403                goto error;
 404        }
 405
 406        v9fs_stat2inode(st, ret, sb);
 407        ret->i_ino = v9fs_qid2ino(&st->qid);
 408
 409#ifdef CONFIG_9P_FSCACHE
 410        v9fs_vcookie_set_qid(ret, &st->qid);
 411        v9fs_cache_inode_get_cookie(ret);
 412#endif
 413        p9stat_free(st);
 414        kfree(st);
 415
 416        return ret;
 417
 418error:
 419        p9stat_free(st);
 420        kfree(st);
 421        return ERR_PTR(err);
 422}
 423
 424/**
 425 * v9fs_remove - helper function to remove files and directories
 426 * @dir: directory inode that is being deleted
 427 * @file:  dentry that is being deleted
 428 * @rmdir: removing a directory
 429 *
 430 */
 431
 432static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 433{
 434        struct inode *file_inode;
 435        struct v9fs_session_info *v9ses;
 436        struct p9_fid *v9fid;
 437
 438        P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
 439                rmdir);
 440
 441        file_inode = file->d_inode;
 442        v9ses = v9fs_inode2v9ses(file_inode);
 443        v9fid = v9fs_fid_clone(file);
 444        if (IS_ERR(v9fid))
 445                return PTR_ERR(v9fid);
 446
 447        return p9_client_remove(v9fid);
 448}
 449
 450static int
 451v9fs_open_created(struct inode *inode, struct file *file)
 452{
 453        return 0;
 454}
 455
 456
 457/**
 458 * v9fs_create - Create a file
 459 * @v9ses: session information
 460 * @dir: directory that dentry is being created in
 461 * @dentry:  dentry that is being created
 462 * @extension: 9p2000.u extension string to support devices, etc.
 463 * @perm: create permissions
 464 * @mode: open mode
 465 *
 466 */
 467static struct p9_fid *
 468v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 469                struct dentry *dentry, char *extension, u32 perm, u8 mode)
 470{
 471        int err;
 472        char *name;
 473        struct p9_fid *dfid, *ofid, *fid;
 474        struct inode *inode;
 475
 476        P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 477
 478        err = 0;
 479        ofid = NULL;
 480        fid = NULL;
 481        name = (char *) dentry->d_name.name;
 482        dfid = v9fs_fid_clone(dentry->d_parent);
 483        if (IS_ERR(dfid)) {
 484                err = PTR_ERR(dfid);
 485                P9_DPRINTK(P9_DEBUG_VFS, "fid clone failed %d\n", err);
 486                dfid = NULL;
 487                goto error;
 488        }
 489
 490        /* clone a fid to use for creation */
 491        ofid = p9_client_walk(dfid, 0, NULL, 1);
 492        if (IS_ERR(ofid)) {
 493                err = PTR_ERR(ofid);
 494                P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 495                ofid = NULL;
 496                goto error;
 497        }
 498
 499        err = p9_client_fcreate(ofid, name, perm, mode, extension);
 500        if (err < 0) {
 501                P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 502                goto error;
 503        }
 504
 505        /* now walk from the parent so we can get unopened fid */
 506        fid = p9_client_walk(dfid, 1, &name, 0);
 507        if (IS_ERR(fid)) {
 508                err = PTR_ERR(fid);
 509                P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 510                fid = NULL;
 511                goto error;
 512        } else
 513                dfid = NULL;
 514
 515        /* instantiate inode and assign the unopened fid to the dentry */
 516        inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 517        if (IS_ERR(inode)) {
 518                err = PTR_ERR(inode);
 519                P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
 520                goto error;
 521        }
 522
 523        if (v9ses->cache)
 524                dentry->d_op = &v9fs_cached_dentry_operations;
 525        else
 526                dentry->d_op = &v9fs_dentry_operations;
 527
 528        d_instantiate(dentry, inode);
 529        err = v9fs_fid_add(dentry, fid);
 530        if (err < 0)
 531                goto error;
 532
 533        return ofid;
 534
 535error:
 536        if (dfid)
 537                p9_client_clunk(dfid);
 538
 539        if (ofid)
 540                p9_client_clunk(ofid);
 541
 542        if (fid)
 543                p9_client_clunk(fid);
 544
 545        return ERR_PTR(err);
 546}
 547
 548/**
 549 * v9fs_vfs_create - VFS hook to create files
 550 * @dir: directory inode that is being created
 551 * @dentry:  dentry that is being deleted
 552 * @mode: create permissions
 553 * @nd: path information
 554 *
 555 */
 556
 557static int
 558v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 559                struct nameidata *nd)
 560{
 561        int err;
 562        u32 perm;
 563        int flags;
 564        struct v9fs_session_info *v9ses;
 565        struct p9_fid *fid;
 566        struct file *filp;
 567
 568        err = 0;
 569        fid = NULL;
 570        v9ses = v9fs_inode2v9ses(dir);
 571        perm = unixmode2p9mode(v9ses, mode);
 572        if (nd && nd->flags & LOOKUP_OPEN)
 573                flags = nd->intent.open.flags - 1;
 574        else
 575                flags = O_RDWR;
 576
 577        fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 578                                v9fs_uflags2omode(flags, v9fs_extended(v9ses)));
 579        if (IS_ERR(fid)) {
 580                err = PTR_ERR(fid);
 581                fid = NULL;
 582                goto error;
 583        }
 584
 585        /* if we are opening a file, assign the open fid to the file */
 586        if (nd && nd->flags & LOOKUP_OPEN) {
 587                filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
 588                if (IS_ERR(filp)) {
 589                        err = PTR_ERR(filp);
 590                        goto error;
 591                }
 592
 593                filp->private_data = fid;
 594        } else
 595                p9_client_clunk(fid);
 596
 597        return 0;
 598
 599error:
 600        if (fid)
 601                p9_client_clunk(fid);
 602
 603        return err;
 604}
 605
 606/**
 607 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 608 * @dir:  inode that is being unlinked
 609 * @dentry: dentry that is being unlinked
 610 * @mode: mode for new directory
 611 *
 612 */
 613
 614static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 615{
 616        int err;
 617        u32 perm;
 618        struct v9fs_session_info *v9ses;
 619        struct p9_fid *fid;
 620
 621        P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 622        err = 0;
 623        v9ses = v9fs_inode2v9ses(dir);
 624        perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 625        fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 626        if (IS_ERR(fid)) {
 627                err = PTR_ERR(fid);
 628                fid = NULL;
 629        }
 630
 631        if (fid)
 632                p9_client_clunk(fid);
 633
 634        return err;
 635}
 636
 637/**
 638 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 639 * @dir:  inode that is being walked from
 640 * @dentry: dentry that is being walked to?
 641 * @nameidata: path data
 642 *
 643 */
 644
 645static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 646                                      struct nameidata *nameidata)
 647{
 648        struct super_block *sb;
 649        struct v9fs_session_info *v9ses;
 650        struct p9_fid *dfid, *fid;
 651        struct inode *inode;
 652        char *name;
 653        int result = 0;
 654
 655        P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 656                dir, dentry->d_name.name, dentry, nameidata);
 657
 658        sb = dir->i_sb;
 659        v9ses = v9fs_inode2v9ses(dir);
 660        dfid = v9fs_fid_lookup(dentry->d_parent);
 661        if (IS_ERR(dfid))
 662                return ERR_CAST(dfid);
 663
 664        name = (char *) dentry->d_name.name;
 665        fid = p9_client_walk(dfid, 1, &name, 1);
 666        if (IS_ERR(fid)) {
 667                result = PTR_ERR(fid);
 668                if (result == -ENOENT) {
 669                        d_add(dentry, NULL);
 670                        return NULL;
 671                }
 672
 673                return ERR_PTR(result);
 674        }
 675
 676        inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 677        if (IS_ERR(inode)) {
 678                result = PTR_ERR(inode);
 679                inode = NULL;
 680                goto error;
 681        }
 682
 683        result = v9fs_fid_add(dentry, fid);
 684        if (result < 0)
 685                goto error;
 686
 687        if ((fid->qid.version) && (v9ses->cache))
 688                dentry->d_op = &v9fs_cached_dentry_operations;
 689        else
 690                dentry->d_op = &v9fs_dentry_operations;
 691
 692        d_add(dentry, inode);
 693        return NULL;
 694
 695error:
 696        p9_client_clunk(fid);
 697
 698        return ERR_PTR(result);
 699}
 700
 701/**
 702 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 703 * @i:  inode that is being unlinked
 704 * @d: dentry that is being unlinked
 705 *
 706 */
 707
 708static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 709{
 710        return v9fs_remove(i, d, 0);
 711}
 712
 713/**
 714 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 715 * @i:  inode that is being unlinked
 716 * @d: dentry that is being unlinked
 717 *
 718 */
 719
 720static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 721{
 722        return v9fs_remove(i, d, 1);
 723}
 724
 725/**
 726 * v9fs_vfs_rename - VFS hook to rename an inode
 727 * @old_dir:  old dir inode
 728 * @old_dentry: old dentry
 729 * @new_dir: new dir inode
 730 * @new_dentry: new dentry
 731 *
 732 */
 733
 734static int
 735v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 736                struct inode *new_dir, struct dentry *new_dentry)
 737{
 738        struct inode *old_inode;
 739        struct v9fs_session_info *v9ses;
 740        struct p9_fid *oldfid;
 741        struct p9_fid *olddirfid;
 742        struct p9_fid *newdirfid;
 743        struct p9_wstat wstat;
 744        int retval;
 745
 746        P9_DPRINTK(P9_DEBUG_VFS, "\n");
 747        retval = 0;
 748        old_inode = old_dentry->d_inode;
 749        v9ses = v9fs_inode2v9ses(old_inode);
 750        oldfid = v9fs_fid_lookup(old_dentry);
 751        if (IS_ERR(oldfid))
 752                return PTR_ERR(oldfid);
 753
 754        olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 755        if (IS_ERR(olddirfid)) {
 756                retval = PTR_ERR(olddirfid);
 757                goto done;
 758        }
 759
 760        newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 761        if (IS_ERR(newdirfid)) {
 762                retval = PTR_ERR(newdirfid);
 763                goto clunk_olddir;
 764        }
 765
 766        /* 9P can only handle file rename in the same directory */
 767        if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
 768                P9_DPRINTK(P9_DEBUG_ERROR,
 769                                "old dir and new dir are different\n");
 770                retval = -EXDEV;
 771                goto clunk_newdir;
 772        }
 773
 774        v9fs_blank_wstat(&wstat);
 775        wstat.muid = v9ses->uname;
 776        wstat.name = (char *) new_dentry->d_name.name;
 777        retval = p9_client_wstat(oldfid, &wstat);
 778
 779clunk_newdir:
 780        p9_client_clunk(newdirfid);
 781
 782clunk_olddir:
 783        p9_client_clunk(olddirfid);
 784
 785done:
 786        return retval;
 787}
 788
 789/**
 790 * v9fs_vfs_getattr - retrieve file metadata
 791 * @mnt: mount information
 792 * @dentry: file to get attributes on
 793 * @stat: metadata structure to populate
 794 *
 795 */
 796
 797static int
 798v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 799                 struct kstat *stat)
 800{
 801        int err;
 802        struct v9fs_session_info *v9ses;
 803        struct p9_fid *fid;
 804        struct p9_wstat *st;
 805
 806        P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 807        err = -EPERM;
 808        v9ses = v9fs_inode2v9ses(dentry->d_inode);
 809        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 810                return simple_getattr(mnt, dentry, stat);
 811
 812        fid = v9fs_fid_lookup(dentry);
 813        if (IS_ERR(fid))
 814                return PTR_ERR(fid);
 815
 816        st = p9_client_stat(fid);
 817        if (IS_ERR(st))
 818                return PTR_ERR(st);
 819
 820        v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
 821                generic_fillattr(dentry->d_inode, stat);
 822
 823        kfree(st);
 824        return 0;
 825}
 826
 827/**
 828 * v9fs_vfs_setattr - set file metadata
 829 * @dentry: file whose metadata to set
 830 * @iattr: metadata assignment structure
 831 *
 832 */
 833
 834static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
 835{
 836        int retval;
 837        struct v9fs_session_info *v9ses;
 838        struct p9_fid *fid;
 839        struct p9_wstat wstat;
 840
 841        P9_DPRINTK(P9_DEBUG_VFS, "\n");
 842        retval = -EPERM;
 843        v9ses = v9fs_inode2v9ses(dentry->d_inode);
 844        fid = v9fs_fid_lookup(dentry);
 845        if(IS_ERR(fid))
 846                return PTR_ERR(fid);
 847
 848        v9fs_blank_wstat(&wstat);
 849        if (iattr->ia_valid & ATTR_MODE)
 850                wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
 851
 852        if (iattr->ia_valid & ATTR_MTIME)
 853                wstat.mtime = iattr->ia_mtime.tv_sec;
 854
 855        if (iattr->ia_valid & ATTR_ATIME)
 856                wstat.atime = iattr->ia_atime.tv_sec;
 857
 858        if (iattr->ia_valid & ATTR_SIZE)
 859                wstat.length = iattr->ia_size;
 860
 861        if (v9fs_extended(v9ses)) {
 862                if (iattr->ia_valid & ATTR_UID)
 863                        wstat.n_uid = iattr->ia_uid;
 864
 865                if (iattr->ia_valid & ATTR_GID)
 866                        wstat.n_gid = iattr->ia_gid;
 867        }
 868
 869        retval = p9_client_wstat(fid, &wstat);
 870        if (retval >= 0)
 871                retval = inode_setattr(dentry->d_inode, iattr);
 872
 873        return retval;
 874}
 875
 876/**
 877 * v9fs_stat2inode - populate an inode structure with mistat info
 878 * @stat: Plan 9 metadata (mistat) structure
 879 * @inode: inode to populate
 880 * @sb: superblock of filesystem
 881 *
 882 */
 883
 884void
 885v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 886        struct super_block *sb)
 887{
 888        char ext[32];
 889        struct v9fs_session_info *v9ses = sb->s_fs_info;
 890
 891        inode->i_nlink = 1;
 892
 893        inode->i_atime.tv_sec = stat->atime;
 894        inode->i_mtime.tv_sec = stat->mtime;
 895        inode->i_ctime.tv_sec = stat->mtime;
 896
 897        inode->i_uid = v9ses->dfltuid;
 898        inode->i_gid = v9ses->dfltgid;
 899
 900        if (v9fs_extended(v9ses)) {
 901                inode->i_uid = stat->n_uid;
 902                inode->i_gid = stat->n_gid;
 903        }
 904
 905        inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
 906        if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
 907                char type = 0;
 908                int major = -1;
 909                int minor = -1;
 910
 911                strncpy(ext, stat->extension, sizeof(ext));
 912                sscanf(ext, "%c %u %u", &type, &major, &minor);
 913                switch (type) {
 914                case 'c':
 915                        inode->i_mode &= ~S_IFBLK;
 916                        inode->i_mode |= S_IFCHR;
 917                        break;
 918                case 'b':
 919                        break;
 920                default:
 921                        P9_DPRINTK(P9_DEBUG_ERROR,
 922                                "Unknown special type %c %s\n", type,
 923                                stat->extension);
 924                };
 925                inode->i_rdev = MKDEV(major, minor);
 926                init_special_inode(inode, inode->i_mode, inode->i_rdev);
 927        } else
 928                inode->i_rdev = 0;
 929
 930        i_size_write(inode, stat->length);
 931
 932        /* not real number of blocks, but 512 byte ones ... */
 933        inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
 934}
 935
 936/**
 937 * v9fs_qid2ino - convert qid into inode number
 938 * @qid: qid to hash
 939 *
 940 * BUG: potential for inode number collisions?
 941 */
 942
 943ino_t v9fs_qid2ino(struct p9_qid *qid)
 944{
 945        u64 path = qid->path + 2;
 946        ino_t i = 0;
 947
 948        if (sizeof(ino_t) == sizeof(path))
 949                memcpy(&i, &path, sizeof(ino_t));
 950        else
 951                i = (ino_t) (path ^ (path >> 32));
 952
 953        return i;
 954}
 955
 956/**
 957 * v9fs_readlink - read a symlink's location (internal version)
 958 * @dentry: dentry for symlink
 959 * @buffer: buffer to load symlink location into
 960 * @buflen: length of buffer
 961 *
 962 */
 963
 964static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
 965{
 966        int retval;
 967
 968        struct v9fs_session_info *v9ses;
 969        struct p9_fid *fid;
 970        struct p9_wstat *st;
 971
 972        P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
 973        retval = -EPERM;
 974        v9ses = v9fs_inode2v9ses(dentry->d_inode);
 975        fid = v9fs_fid_lookup(dentry);
 976        if (IS_ERR(fid))
 977                return PTR_ERR(fid);
 978
 979        if (!v9fs_extended(v9ses))
 980                return -EBADF;
 981
 982        st = p9_client_stat(fid);
 983        if (IS_ERR(st))
 984                return PTR_ERR(st);
 985
 986        if (!(st->mode & P9_DMSYMLINK)) {
 987                retval = -EINVAL;
 988                goto done;
 989        }
 990
 991        /* copy extension buffer into buffer */
 992        strncpy(buffer, st->extension, buflen);
 993
 994        P9_DPRINTK(P9_DEBUG_VFS,
 995                "%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
 996
 997        retval = strnlen(buffer, buflen);
 998done:
 999        kfree(st);
1000        return retval;
1001}
1002
1003/**
1004 * v9fs_vfs_readlink - read a symlink's location
1005 * @dentry: dentry for symlink
1006 * @buffer: buffer to load symlink location into
1007 * @buflen: length of buffer
1008 *
1009 */
1010
1011static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
1012                             int buflen)
1013{
1014        int retval;
1015        int ret;
1016        char *link = __getname();
1017
1018        if (unlikely(!link))
1019                return -ENOMEM;
1020
1021        if (buflen > PATH_MAX)
1022                buflen = PATH_MAX;
1023
1024        P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_name.name,
1025                                                                        dentry);
1026
1027        retval = v9fs_readlink(dentry, link, buflen);
1028
1029        if (retval > 0) {
1030                if ((ret = copy_to_user(buffer, link, retval)) != 0) {
1031                        P9_DPRINTK(P9_DEBUG_ERROR,
1032                                        "problem copying to user: %d\n", ret);
1033                        retval = ret;
1034                }
1035        }
1036
1037        __putname(link);
1038        return retval;
1039}
1040
1041/**
1042 * v9fs_vfs_follow_link - follow a symlink path
1043 * @dentry: dentry for symlink
1044 * @nd: nameidata
1045 *
1046 */
1047
1048static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1049{
1050        int len = 0;
1051        char *link = __getname();
1052
1053        P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1054
1055        if (!link)
1056                link = ERR_PTR(-ENOMEM);
1057        else {
1058                len = v9fs_readlink(dentry, link, PATH_MAX);
1059
1060                if (len < 0) {
1061                        __putname(link);
1062                        link = ERR_PTR(len);
1063                } else
1064                        link[min(len, PATH_MAX-1)] = 0;
1065        }
1066        nd_set_link(nd, link);
1067
1068        return NULL;
1069}
1070
1071/**
1072 * v9fs_vfs_put_link - release a symlink path
1073 * @dentry: dentry for symlink
1074 * @nd: nameidata
1075 * @p: unused
1076 *
1077 */
1078
1079static void
1080v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1081{
1082        char *s = nd_get_link(nd);
1083
1084        P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1085                IS_ERR(s) ? "<error>" : s);
1086        if (!IS_ERR(s))
1087                __putname(s);
1088}
1089
1090/**
1091 * v9fs_vfs_mkspecial - create a special file
1092 * @dir: inode to create special file in
1093 * @dentry: dentry to create
1094 * @mode: mode to create special file
1095 * @extension: 9p2000.u format extension string representing special file
1096 *
1097 */
1098
1099static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1100        int mode, const char *extension)
1101{
1102        u32 perm;
1103        struct v9fs_session_info *v9ses;
1104        struct p9_fid *fid;
1105
1106        v9ses = v9fs_inode2v9ses(dir);
1107        if (!v9fs_extended(v9ses)) {
1108                P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1109                return -EPERM;
1110        }
1111
1112        perm = unixmode2p9mode(v9ses, mode);
1113        fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1114                                                                P9_OREAD);
1115        if (IS_ERR(fid))
1116                return PTR_ERR(fid);
1117
1118        p9_client_clunk(fid);
1119        return 0;
1120}
1121
1122/**
1123 * v9fs_vfs_symlink - helper function to create symlinks
1124 * @dir: directory inode containing symlink
1125 * @dentry: dentry for symlink
1126 * @symname: symlink data
1127 *
1128 * See Also: 9P2000.u RFC for more information
1129 *
1130 */
1131
1132static int
1133v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1134{
1135        P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1136                                        dentry->d_name.name, symname);
1137
1138        return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1139}
1140
1141/**
1142 * v9fs_vfs_link - create a hardlink
1143 * @old_dentry: dentry for file to link to
1144 * @dir: inode destination for new link
1145 * @dentry: dentry for link
1146 *
1147 */
1148
1149static int
1150v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1151              struct dentry *dentry)
1152{
1153        int retval;
1154        struct p9_fid *oldfid;
1155        char *name;
1156
1157        P9_DPRINTK(P9_DEBUG_VFS,
1158                " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1159                old_dentry->d_name.name);
1160
1161        oldfid = v9fs_fid_clone(old_dentry);
1162        if (IS_ERR(oldfid))
1163                return PTR_ERR(oldfid);
1164
1165        name = __getname();
1166        if (unlikely(!name)) {
1167                retval = -ENOMEM;
1168                goto clunk_fid;
1169        }
1170
1171        sprintf(name, "%d\n", oldfid->fid);
1172        retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1173        __putname(name);
1174
1175clunk_fid:
1176        p9_client_clunk(oldfid);
1177        return retval;
1178}
1179
1180/**
1181 * v9fs_vfs_mknod - create a special file
1182 * @dir: inode destination for new link
1183 * @dentry: dentry for file
1184 * @mode: mode for creation
1185 * @rdev: device associated with special file
1186 *
1187 */
1188
1189static int
1190v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1191{
1192        int retval;
1193        char *name;
1194
1195        P9_DPRINTK(P9_DEBUG_VFS,
1196                " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1197                dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1198
1199        if (!new_valid_dev(rdev))
1200                return -EINVAL;
1201
1202        name = __getname();
1203        if (!name)
1204                return -ENOMEM;
1205        /* build extension */
1206        if (S_ISBLK(mode))
1207                sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1208        else if (S_ISCHR(mode))
1209                sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1210        else if (S_ISFIFO(mode))
1211                *name = 0;
1212        else {
1213                __putname(name);
1214                return -EINVAL;
1215        }
1216
1217        retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1218        __putname(name);
1219
1220        return retval;
1221}
1222
1223static const struct inode_operations v9fs_dir_inode_operations_ext = {
1224        .create = v9fs_vfs_create,
1225        .lookup = v9fs_vfs_lookup,
1226        .symlink = v9fs_vfs_symlink,
1227        .link = v9fs_vfs_link,
1228        .unlink = v9fs_vfs_unlink,
1229        .mkdir = v9fs_vfs_mkdir,
1230        .rmdir = v9fs_vfs_rmdir,
1231        .mknod = v9fs_vfs_mknod,
1232        .rename = v9fs_vfs_rename,
1233        .readlink = v9fs_vfs_readlink,
1234        .getattr = v9fs_vfs_getattr,
1235        .setattr = v9fs_vfs_setattr,
1236};
1237
1238static const struct inode_operations v9fs_dir_inode_operations = {
1239        .create = v9fs_vfs_create,
1240        .lookup = v9fs_vfs_lookup,
1241        .unlink = v9fs_vfs_unlink,
1242        .mkdir = v9fs_vfs_mkdir,
1243        .rmdir = v9fs_vfs_rmdir,
1244        .mknod = v9fs_vfs_mknod,
1245        .rename = v9fs_vfs_rename,
1246        .getattr = v9fs_vfs_getattr,
1247        .setattr = v9fs_vfs_setattr,
1248};
1249
1250static const struct inode_operations v9fs_file_inode_operations = {
1251        .getattr = v9fs_vfs_getattr,
1252        .setattr = v9fs_vfs_setattr,
1253};
1254
1255static const struct inode_operations v9fs_symlink_inode_operations = {
1256        .readlink = v9fs_vfs_readlink,
1257        .follow_link = v9fs_vfs_follow_link,
1258        .put_link = v9fs_vfs_put_link,
1259        .getattr = v9fs_vfs_getattr,
1260        .setattr = v9fs_vfs_setattr,
1261};
1262