lustre/obdfilter/filter.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  *  linux/fs/obdfilter/filter.c
   5  *
   6  * Copyright (C) 2001, 2002 Cluster File Systems, Inc.
   7  *
   8  * This code is issued under the GNU General Public License.
   9  * See the file COPYING in this distribution
  10  *
  11  * by Peter Braam <braam@clusterfs.com>
  12  * and Andreas Dilger <adilger@clusterfs.com>
  13  */
  14
  15 #define EXPORT_SYMTAB
  16 #define DEBUG_SUBSYSTEM S_FILTER
  17
  18 #include <linux/module.h>
  19 #include <linux/lustre_dlm.h>
  20 #include <linux/obd_filter.h>
  21 #include <linux/ext3_jbd.h>
  22 #include <linux/quotaops.h>
  23 #include <linux/init.h>
  24
  25 extern struct obd_device obd_dev[MAX_OBD_DEVICES];
  26 long filter_memory;
  27
  28 #define FILTER_ROOTINO 2
  29
  30 #define S_SHIFT 12
  31 static char *obd_type_by_mode[S_IFMT >> S_SHIFT] = {
  32         [0]                     NULL,
  33         [S_IFREG >> S_SHIFT]    "R",
  34         [S_IFDIR >> S_SHIFT]    "D",
  35         [S_IFCHR >> S_SHIFT]    "C",
  36         [S_IFBLK >> S_SHIFT]    "B",
  37         [S_IFIFO >> S_SHIFT]    "F",
  38         [S_IFSOCK >> S_SHIFT]   "S",
  39         [S_IFLNK >> S_SHIFT]    "L"
  40 };
  41
  42 static inline const char *obd_mode_to_type(int mode)
  43 {
  44         return obd_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
  45 }
  46
  47 /* write the pathname into the string */
  48 static int filter_id(char *buf, obd_id id, obd_mode mode)
  49 {
  50         return sprintf(buf, "O/%s/%Ld", obd_mode_to_type(mode),
  51                        (unsigned long long)id);
  52 }
  53
  54 static inline void f_dput(struct dentry *dentry)
  55 {
  56         CDEBUG(D_INODE, "putting %s: %p, count = %d\n",
  57                dentry->d_name.name, dentry, atomic_read(&dentry->d_count) - 1);
  58         LASSERT(atomic_read(&dentry->d_count) > 0);
  59         dput(dentry);
  60 }
  61
  62 /* setup the object store with correct subdirectories */
  63 static int filter_prep(struct obd_device *obddev)
  64 {
  65         struct obd_run_ctxt saved;
  66         struct filter_obd *filter = &obddev->u.filter;
  67         struct dentry *dentry;
  68         struct file *file;
  69         struct inode *inode;
  70         int rc = 0;
  71         char rootid[128];
  72         __u64 lastino = 2;
  73         int mode = 0;
  74
  75         push_ctxt(&saved, &filter->fo_ctxt);
  76         dentry = simple_mkdir(current->fs->pwd, "O", 0700);
  77         CDEBUG(D_INODE, "got/created O: %p\n", dentry);
  78         if (IS_ERR(dentry)) {
  79                 rc = PTR_ERR(dentry);
  80                 CERROR("cannot open/create O: rc = %d\n", rc);
  81                 GOTO(out, rc);
  82         }
  83         filter->fo_dentry_O = dentry;
  84         dentry = simple_mkdir(current->fs->pwd, "P", 0700);
  85         CDEBUG(D_INODE, "got/created P: %p\n", dentry);
  86         if (IS_ERR(dentry)) {
  87                 rc = PTR_ERR(dentry);
  88                 CERROR("cannot open/create P: rc = %d\n", rc);
  89                 GOTO(out_O, rc);
  90         }
  91         CDEBUG(D_INODE, "putting P: %p, count = %d\n", dentry,
  92                atomic_read(&dentry->d_count) - 1);
  93         f_dput(dentry);
  94         dentry = simple_mkdir(current->fs->pwd, "D", 0700);
  95         CDEBUG(D_INODE, "got/created D: %p\n", dentry);
  96         if (IS_ERR(dentry)) {
  97                 rc = PTR_ERR(dentry);
  98                 CERROR("cannot open/create D: rc = %d\n", rc);
  99                 GOTO(out_O, rc);
 100         }
 101         CDEBUG(D_INODE, "putting D: %p, count = %d\n", dentry,
 102                atomic_read(&dentry->d_count) - 1);
 103         f_dput(dentry);
 104
 105         /*
 106          * Create directories and/or get dentries for each object type.
 107          * This saves us from having to do multiple lookups for each one.
 108          */
 109         for (mode = 0; mode < (S_IFMT >> S_SHIFT); mode++) {
 110                 char *type = obd_type_by_mode[mode];
 111
 112                 if (!type) {
 113                         filter->fo_dentry_O_mode[mode] = NULL;
 114                         continue;
 115                 }
 116                 dentry = simple_mkdir(filter->fo_dentry_O, type, 0700);
 117                 CDEBUG(D_INODE, "got/created O/%s: %p\n", type, dentry);
 118                 if (IS_ERR(dentry)) {
 119                         rc = PTR_ERR(dentry);
 120                         CERROR("cannot create O/%s: rc = %d\n", type, rc);
 121                         GOTO(out_O_mode, rc);
 122                 }
 123                 filter->fo_dentry_O_mode[mode] = dentry;
 124         }
 125
 126         filter_id(rootid, FILTER_ROOTINO, S_IFDIR);
 127         file = filp_open(rootid, O_RDWR | O_CREAT, 0755);
 128         if (IS_ERR(file)) {
 129                 rc = PTR_ERR(file);
 130                 CERROR("OBD filter: cannot open/create root %s: rc = %d\n",
 131                        rootid, rc);
 132                 GOTO(out_O_mode, rc);
 133         }
 134         filp_close(file, 0);
 135
 136         file = filp_open("D/status", O_RDWR | O_CREAT, 0700);
 137         if ( !file || IS_ERR(file) ) {
 138                 rc = PTR_ERR(file);
 139                 CERROR("OBD filter: cannot open/create status %s: rc = %d\n",
 140                        "D/status", rc);
 141                 GOTO(out_O_mode, rc);
 142         }
 143
 144         /* steal operations */
 145         inode = file->f_dentry->d_inode;
 146         filter->fo_fop = file->f_op;
 147         filter->fo_iop = inode->i_op;
 148         filter->fo_aops = inode->i_mapping->a_ops;
 149
 150         if (inode->i_size == 0) {
 151                 __u64 disk_lastino = cpu_to_le64(lastino);
 152                 ssize_t retval = file->f_op->write(file, (char *)&disk_lastino,
 153                                                    sizeof(disk_lastino),
 154                                                    &file->f_pos);
 155                 if (retval != sizeof(disk_lastino)) {
 156                         CDEBUG(D_INODE, "OBD filter: error writing lastino\n");
 157                         filp_close(file, 0);
 158                         GOTO(out_O_mode, rc = -EIO);
 159                 }
 160         } else {
 161                 __u64 disk_lastino;
 162                 ssize_t retval = file->f_op->read(file, (char *)&disk_lastino,
 163                                                   sizeof(disk_lastino),
 164                                                   &file->f_pos);
 165                 if (retval != sizeof(disk_lastino)) {
 166                         CDEBUG(D_INODE, "OBD filter: error reading lastino\n");
 167                         filp_close(file, 0);
 168                         GOTO(out_O_mode, rc = -EIO);
 169                 }
 170                 lastino = le64_to_cpu(disk_lastino);
 171         }
 172         filter->fo_lastino = lastino;
 173         filp_close(file, 0);
 174
 175         rc = 0;
 176  out:
 177         pop_ctxt(&saved);
 178
 179         return(rc);
 180
 181 out_O_mode:
 182         while (mode-- > 0) {
 183                 struct dentry *dentry = filter->fo_dentry_O_mode[mode];
 184                 if (dentry) {
 185                         f_dput(dentry);
 186                         filter->fo_dentry_O_mode[mode] = NULL;
 187                 }
 188         }
 189 out_O:
 190         f_dput(filter->fo_dentry_O);
 191         filter->fo_dentry_O = NULL;
 192         goto out;
 193 }
 194
 195 /* cleanup the filter: write last used object id to status file */
 196 static void filter_post(struct obd_device *obddev)
 197 {
 198         struct obd_run_ctxt saved;
 199         struct filter_obd *filter = &obddev->u.filter;
 200         __u64 disk_lastino;
 201         long rc;
 202         struct file *file;
 203         int mode;
 204
 205         push_ctxt(&saved, &filter->fo_ctxt);
 206         file = filp_open("D/status", O_RDWR | O_CREAT, 0700);
 207         if (IS_ERR(file)) {
 208                 CERROR("OBD filter: cannot create status file\n");
 209                 goto out;
 210         }
 211
 212         file->f_pos = 0;
 213         disk_lastino = cpu_to_le64(filter->fo_lastino);
 214         rc = file->f_op->write(file, (char *)&disk_lastino,
 215                        sizeof(disk_lastino), &file->f_pos);
 216         if (rc != sizeof(disk_lastino))
 217                 CERROR("OBD filter: error writing lastino: rc = %ld\n", rc);
 218
 219         rc = filp_close(file, NULL);
 220         if (rc)
 221                 CERROR("OBD filter: cannot close status file: rc = %ld\n", rc);
 222
 223         for (mode = 0; mode < (S_IFMT >> S_SHIFT); mode++) {
 224                 struct dentry *dentry = filter->fo_dentry_O_mode[mode];
 225                 if (dentry) {
 226                         f_dput(dentry);
 227                         filter->fo_dentry_O_mode[mode] = NULL;
 228                 }
 229         }
 230         f_dput(filter->fo_dentry_O);
 231 out:
 232         pop_ctxt(&saved);
 233 }
 234
 235
 236 static __u64 filter_next_id(struct obd_device *obddev)
 237 {
 238         obd_id id;
 239
 240         spin_lock(&obddev->u.filter.fo_lock);
 241         id = ++obddev->u.filter.fo_lastino;
 242         spin_unlock(&obddev->u.filter.fo_lock);
 243
 244         /* FIXME: write the lastino to disk here */
 245         return id;
 246 }
 247
 248 /* how to get files, dentries, inodes from object id's */
 249 /* parent i_sem is already held if needed for exclusivity */
 250 static struct dentry *filter_fid2dentry(struct obd_device *obddev,
 251                                         struct dentry *dparent,
 252                                         __u64 id, __u32 type)
 253 {
 254         struct super_block *sb = obddev->u.filter.fo_sb;
 255         struct dentry *dchild;
 256         char name[32];
 257         int len;
 258         ENTRY;
 259
 260         if (!sb || !sb->s_dev) {
 261                 CERROR("fatal: device not initialized.\n");
 262                 RETURN(ERR_PTR(-ENXIO));
 263         }
 264
 265         if (id == 0) {
 266                 CERROR("fatal: invalid object #0\n");
 267                 LBUG();
 268                 RETURN(ERR_PTR(-ESTALE));
 269         }
 270
 271         if (!(type & S_IFMT)) {
 272                 CERROR("OBD %s, object %Lu has bad type: %o\n", __FUNCTION__,
 273                        (unsigned long long)id, type);
 274                 RETURN(ERR_PTR(-EINVAL));
 275         }
 276
 277         len = sprintf(name, "%Ld", id);
 278         CDEBUG(D_INODE, "opening object O/%s/%s\n", obd_mode_to_type(type),
 279                name);
 280         dchild = lookup_one_len(name, dparent, len);
 281         if (IS_ERR(dchild)) {
 282                 CERROR("child lookup error %ld\n", PTR_ERR(dchild));
 283                 RETURN(dchild);
 284         }
 285
 286         CDEBUG(D_INODE, "got child obj O/%s/%s: %p, count = %d\n",
 287                obd_mode_to_type(type), name, dchild,
 288                atomic_read(&dchild->d_count));
 289
 290         LASSERT(atomic_read(&dchild->d_count) > 0);
 291
 292         RETURN(dchild);
 293 }
 294
 295 static struct file *filter_obj_open(struct obd_device *obddev,
 296                                     __u64 id, __u32 type)
 297 {
 298         struct super_block *sb = obddev->u.filter.fo_sb;
 299         struct obd_run_ctxt saved;
 300         char name[24];
 301         struct file *file;
 302         ENTRY;
 303
 304         if (!sb || !sb->s_dev) {
 305                 CERROR("fatal: device not initialized.\n");
 306                 RETURN(ERR_PTR(-ENXIO));
 307         }
 308
 309         if (!id) {
 310                 CERROR("fatal: invalid obdo %Lu\n", (unsigned long long)id);
 311                 RETURN(ERR_PTR(-ESTALE));
 312         }
 313
 314         if (!(type & S_IFMT)) {
 315                 CERROR("OBD %s, no type (%Ld), mode %o!\n", __FUNCTION__,
 316                        (unsigned long long)id, type);
 317                 RETURN(ERR_PTR(-EINVAL));
 318         }
 319
 320         filter_id(name, id, type);
 321         push_ctxt(&saved, &obddev->u.filter.fo_ctxt);
 322         file = filp_open(name, O_RDONLY | O_LARGEFILE, 0 /* type? */);
 323         pop_ctxt(&saved);
 324
 325         CDEBUG(D_INODE, "opening obdo %s: rc = %p\n", name, file);
 326
 327         if (IS_ERR(file))
 328                 file = NULL;
 329         RETURN(file);
 330 }
 331
 332 static struct dentry *filter_parent(struct obd_device *obddev, obd_mode mode)
 333 {
 334         struct filter_obd *filter = &obddev->u.filter;
 335
 336         return filter->fo_dentry_O_mode[(mode & S_IFMT) >> S_SHIFT];
 337 }
 338
 339
 340 /* obd methods */
 341 static int filter_connect(struct lustre_handle *conn, struct obd_device *obd,
 342                           char *cluuid)
 343 {
 344         int rc;
 345         ENTRY;
 346         MOD_INC_USE_COUNT;
 347         rc = class_connect(conn, obd, cluuid);
 348         if (rc)
 349                 MOD_DEC_USE_COUNT;
 350         RETURN(rc);
 351 }
 352
 353 static int filter_disconnect(struct lustre_handle *conn)
 354 {
 355         int rc;
 356         ENTRY;
 357
 358         rc = class_disconnect(conn);
 359         if (!rc)
 360                 MOD_DEC_USE_COUNT;
 361
 362         /* XXX cleanup preallocated inodes */
 363         RETURN(rc);
 364 }
 365
 366 /* mount the file system (secretly) */
 367 static int filter_setup(struct obd_device *obddev, obd_count len, void *buf)
 368 {
 369         struct obd_ioctl_data* data = buf;
 370         struct filter_obd *filter;
 371         struct vfsmount *mnt;
 372         int err = 0;
 373         ENTRY;
 374
 375         if (!data->ioc_inlbuf1 || !data->ioc_inlbuf2)
 376                 RETURN(-EINVAL);
 377
 378         MOD_INC_USE_COUNT;
 379         mnt = do_kern_mount(data->ioc_inlbuf2, 0, data->ioc_inlbuf1, NULL);
 380         err = PTR_ERR(mnt);
 381         if (IS_ERR(mnt))
 382                 GOTO(err_dec, err);
 383
 384         filter = &obddev->u.filter;;
 385         filter->fo_vfsmnt = mnt;
 386         filter->fo_fstype = strdup(data->ioc_inlbuf2);
 387         filter->fo_sb = mnt->mnt_root->d_inode->i_sb;
 388         /* XXX is this even possible if do_kern_mount succeeded? */
 389         if (!filter->fo_sb)
 390                 GOTO(err_kfree, err = -ENODEV);
 391
 392         OBD_SET_CTXT_MAGIC(&filter->fo_ctxt);
 393         filter->fo_ctxt.pwdmnt = mnt;
 394         filter->fo_ctxt.pwd = mnt->mnt_root;
 395         filter->fo_ctxt.fs = get_ds();
 396
 397         err = filter_prep(obddev);
 398         if (err)
 399                 GOTO(err_kfree, err);
 400         spin_lock_init(&filter->fo_lock);
 401
 402         obddev->obd_namespace =
 403                 ldlm_namespace_new("filter-tgt", LDLM_NAMESPACE_SERVER);
 404         if (obddev->obd_namespace == NULL)
 405                 LBUG();
 406
 407         ptlrpc_init_client(LDLM_REQUEST_PORTAL, LDLM_REPLY_PORTAL,
 408                            "filter_ldlm_client", &obddev->obd_ldlm_client);
 409
 410         RETURN(0);
 411
 412 err_kfree:
 413         kfree(filter->fo_fstype);
 414         unlock_kernel();
 415         mntput(filter->fo_vfsmnt);
 416         filter->fo_sb = 0;
 417         lock_kernel();
 418
 419 err_dec:
 420         MOD_DEC_USE_COUNT;
 421         return err;
 422 }
 423
 424
 425 static int filter_cleanup(struct obd_device * obddev)
 426 {
 427         struct super_block *sb;
 428         ENTRY;
 429
 430         if (!list_empty(&obddev->obd_exports)) {
 431                 CERROR("still has clients!\n");
 432                 class_disconnect_all(obddev);
 433                 if (!list_empty(&obddev->obd_exports)) {
 434                         CERROR("still has exports after forced cleanup?\n");
 435                         RETURN(-EBUSY);
 436                 }
 437         }
 438
 439         ldlm_namespace_free(obddev->obd_namespace);
 440
 441         sb = obddev->u.filter.fo_sb;
 442         if (!obddev->u.filter.fo_sb)
 443                 RETURN(0);
 444
 445         filter_post(obddev);
 446
 447         shrink_dcache_parent(sb->s_root);
 448         unlock_kernel();
 449         mntput(obddev->u.filter.fo_vfsmnt);
 450         obddev->u.filter.fo_sb = 0;
 451         kfree(obddev->u.filter.fo_fstype);
 452
 453         lock_kernel();
 454
 455         MOD_DEC_USE_COUNT;
 456         RETURN(0);
 457 }
 458
 459
 460 static inline void filter_from_inode(struct obdo *oa, struct inode *inode,
 461                                      int valid)
 462 {
 463         int type = oa->o_mode & S_IFMT;
 464         ENTRY;
 465
 466         CDEBUG(D_INFO, "src inode %ld (%p), dst obdo %ld valid 0x%08x\n",
 467                inode->i_ino, inode, (long)oa->o_id, valid);
 468         /* Don't copy the inode number in place of the object ID */
 469         obdo_from_inode(oa, inode, valid);
 470         oa->o_mode &= ~S_IFMT;
 471         oa->o_mode |= type;
 472
 473         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
 474                 obd_rdev rdev = kdev_t_to_nr(inode->i_rdev);
 475                 oa->o_rdev = rdev;
 476                 oa->o_valid |= OBD_MD_FLRDEV;
 477         }
 478
 479         EXIT;
 480 }
 481
 482 static int filter_getattr(struct lustre_handle *conn, struct obdo *oa,
 483                           struct lov_stripe_md *md)
 484 {
 485         struct obd_device *obddev = class_conn2obd(conn);
 486         struct dentry *dentry;
 487         ENTRY;
 488
 489         if (!class_conn2export(conn)) {
 490                 CDEBUG(D_IOCTL, "fatal: invalid client %Lx\n", conn->addr);
 491                 RETURN(-EINVAL);
 492         }
 493
 494         obddev = class_conn2obd(conn);
 495         dentry = filter_fid2dentry(obddev, filter_parent(obddev, oa->o_mode),
 496                                    oa->o_id, oa->o_mode);
 497         if (IS_ERR(dentry))
 498                 RETURN(PTR_ERR(dentry));
 499
 500         filter_from_inode(oa, dentry->d_inode, oa->o_valid);
 501
 502         f_dput(dentry);
 503         RETURN(0);
 504 }
 505
 506 static int filter_setattr(struct lustre_handle *conn, struct obdo *oa,
 507                           struct lov_stripe_md *md)
 508 {
 509         struct obd_run_ctxt saved;
 510         struct obd_device *obd = class_conn2obd(conn);
 511         struct dentry *dentry;
 512         struct iattr iattr;
 513         struct inode *inode;
 514         int rc;
 515         ENTRY;
 516
 517         iattr_from_obdo(&iattr, oa, oa->o_valid);
 518         iattr.ia_mode = (iattr.ia_mode & ~S_IFMT) | S_IFREG;
 519         dentry = filter_fid2dentry(obd, filter_parent(obd, iattr.ia_mode),
 520                                    oa->o_id, iattr.ia_mode);
 521         if (IS_ERR(dentry))
 522                 RETURN(PTR_ERR(dentry));
 523
 524         inode = dentry->d_inode;
 525         if (!inode) {
 526                 CERROR("setattr on non-existent object: "LPU64"\n", oa->o_id);
 527                 GOTO(out_setattr, rc = -ENOENT);
 528         }
 529
 530         lock_kernel();
 531         if (iattr.ia_valid & ATTR_SIZE)
 532                 down(&inode->i_sem);
 533         push_ctxt(&saved, &obd->u.filter.fo_ctxt);
 534         if (inode->i_op->setattr)
 535                 rc = inode->i_op->setattr(dentry, &iattr);
 536         else
 537                 rc = inode_setattr(inode, &iattr);
 538         pop_ctxt(&saved);
 539         if (iattr.ia_valid & ATTR_SIZE) {
 540                 up(&inode->i_sem);
 541                 oa->o_valid = OBD_MD_FLBLOCKS | OBD_MD_FLCTIME | OBD_MD_FLMTIME;
 542                 obdo_from_inode(oa, inode, oa->o_valid);
 543         }
 544         unlock_kernel();
 545
 546 out_setattr:
 547         f_dput(dentry);
 548         RETURN(rc);
 549 }
 550
 551 static int filter_open(struct lustre_handle *conn, struct obdo *oa,
 552                           struct lov_stripe_md *ea)
 553 {
 554         struct obd_export *export;
 555         struct obd_device *obd;
 556         struct dentry *dentry;
 557         /* ENTRY; */
 558
 559         export = class_conn2export(conn);
 560         if (!export) {
 561                 CDEBUG(D_IOCTL, "fatal: invalid client %Lx\n", conn->addr);
 562                 RETURN(-EINVAL);
 563         }
 564
 565         obd = export->exp_obd;
 566         dentry = filter_fid2dentry(obd, filter_parent(obd, oa->o_mode),
 567                                    oa->o_id, oa->o_mode);
 568         if (IS_ERR(dentry))
 569                 RETURN(PTR_ERR(dentry));
 570
 571         filter_from_inode(oa, dentry->d_inode, OBD_MD_FLSIZE | OBD_MD_FLBLOCKS |
 572                           OBD_MD_FLMTIME | OBD_MD_FLCTIME);
 573
 574         return 0;
 575 } /* filter_open */
 576
 577 static int filter_close(struct lustre_handle *conn, struct obdo *oa,
 578                         struct lov_stripe_md *ea)
 579 {
 580         struct obd_device *obd;
 581         struct dentry *dentry;
 582         /* ENTRY; */
 583
 584         obd = class_conn2obd(conn);
 585         if (!obd) {
 586                 CDEBUG(D_IOCTL, "fatal: invalid client %Lx\n", conn->addr);
 587                 RETURN(-EINVAL);
 588         }
 589
 590         dentry = filter_fid2dentry(obd, filter_parent(obd, oa->o_mode),
 591                                    oa->o_id, oa->o_mode);
 592         if (IS_ERR(dentry))
 593                 RETURN(PTR_ERR(dentry));
 594         LASSERT(atomic_read(&dentry->d_count) > 1);
 595
 596         f_dput(dentry);  /* for the close */
 597         f_dput(dentry);  /* for this call */
 598         return 0;
 599 } /* filter_close */
 600
 601 static int filter_create(struct lustre_handle* conn, struct obdo *oa,
 602                          struct lov_stripe_md **ea)
 603 {
 604         char name[64];
 605         struct obd_run_ctxt saved;
 606         struct file *file;
 607         int mode;
 608         struct obd_device *obd = class_conn2obd(conn);
 609         struct iattr;
 610         ENTRY;
 611
 612         if (!obd) {
 613                 CERROR("invalid client %Lx\n", conn->addr);
 614                 return -EINVAL;
 615         }
 616
 617         if (!(oa->o_mode && S_IFMT)) {
 618                 CERROR("filter obd: no type!\n");
 619                 return -ENOENT;
 620         }
 621
 622         oa->o_id = filter_next_id(obd);
 623
 624         filter_id(name, oa->o_id, oa->o_mode);
 625         mode = (oa->o_mode & ~S_IFMT) | S_IFREG;
 626         push_ctxt(&saved, &obd->u.filter.fo_ctxt);
 627         file = filp_open(name, O_RDONLY | O_CREAT, mode);
 628         pop_ctxt(&saved);
 629         if (IS_ERR(file)) {
 630                 CERROR("Error mknod obj %s, err %ld\n", name, PTR_ERR(file));
 631                 return -ENOENT;
 632         }
 633
 634         /* Set flags for fields we have set in the inode struct */
 635         oa->o_valid = OBD_MD_FLID | OBD_MD_FLBLKSZ | OBD_MD_FLBLOCKS |
 636                  OBD_MD_FLMTIME | OBD_MD_FLATIME | OBD_MD_FLCTIME;
 637         filter_from_inode(oa, file->f_dentry->d_inode, oa->o_valid);
 638         filp_close(file, 0);
 639
 640         return 0;
 641 }
 642
 643 static int filter_destroy(struct lustre_handle *conn, struct obdo *oa,
 644                           struct lov_stripe_md *ea)
 645 {
 646         struct obd_device *obd;
 647         struct filter_obd *filter;
 648         struct obd_run_ctxt saved;
 649         struct inode *inode;
 650         struct dentry *dir_dentry, *object_dentry;
 651         int rc;
 652         ENTRY;
 653
 654         obd = class_conn2obd(conn);
 655         if (!obd) {
 656                 CERROR("invalid client %Lx\n", conn->addr);
 657                 RETURN(-EINVAL);
 658         }
 659
 660         CDEBUG(D_INODE, "destroying object %Ld\n", oa->o_id);
 661
 662         dir_dentry = filter_parent(obd, oa->o_mode);
 663         down(&dir_dentry->d_inode->i_sem);
 664
 665         object_dentry = filter_fid2dentry(obd, dir_dentry, oa->o_id,
 666                                           oa->o_mode);
 667         if (IS_ERR(object_dentry))
 668                 GOTO(out, rc = -ENOENT);
 669
 670         inode = object_dentry->d_inode;
 671         if (inode == NULL) {
 672                 CERROR("trying to destroy negative inode %Ld!\n", oa->o_id);
 673                 GOTO(out, rc = -ENOENT);
 674         }
 675
 676         if (inode->i_nlink != 1) {
 677                 CERROR("destroying inode with nlink = %d\n", inode->i_nlink);
 678                 LBUG();
 679                 inode->i_nlink = 1;
 680         }
 681         inode->i_mode = S_IFREG;
 682
 683         filter = &obd->u.filter;
 684         push_ctxt(&saved, &filter->fo_ctxt);
 685
 686         rc = vfs_unlink(dir_dentry->d_inode, object_dentry);
 687         pop_ctxt(&saved);
 688         f_dput(object_dentry);
 689
 690         EXIT;
 691 out:
 692         up(&dir_dentry->d_inode->i_sem);
 693         return rc;
 694 }
 695
 696 /* NB count and offset are used for punch, but not truncate */
 697 static int filter_truncate(struct lustre_handle *conn, struct obdo *oa,
 698                            struct lov_stripe_md *md,
 699                            obd_off start, obd_off end)
 700 {
 701         int error;
 702         ENTRY;
 703
 704         if (end != 0xffffffffffffffff)
 705                 CERROR("PUNCH not supported, only truncate works\n");
 706
 707         CDEBUG(D_INODE, "calling truncate for object #%Ld, valid = %x, "
 708                "o_size = %Ld\n", oa->o_id, oa->o_valid, start);
 709         oa->o_size = start;
 710         error = filter_setattr(conn, oa, NULL);
 711         RETURN(error);
 712 }
 713
 714 static int filter_pgcache_brw(int cmd, struct lustre_handle *conn,
 715                               struct lov_stripe_md *md, obd_count oa_bufs,
 716                               struct brw_page *pga, brw_callback_t callback,
 717                               struct io_cb_data *data)
 718 {
 719         struct obd_run_ctxt      saved;
 720         struct super_block      *sb;
 721         int                      pnum;          /* index to pages (bufs) */
 722         unsigned long            retval;
 723         int                      error;
 724         struct file             *file;
 725         struct obd_device       *obd = class_conn2obd(conn);
 726         int pg;
 727         ENTRY;
 728
 729         if (!obd) {
 730                 CDEBUG(D_IOCTL, "invalid client %Lx\n", conn->addr);
 731                 RETURN(-EINVAL);
 732         }
 733
 734         sb = obd->u.filter.fo_sb;
 735         push_ctxt(&saved, &obd->u.filter.fo_ctxt);
 736         pnum = 0; /* pnum indexes buf 0..num_pages */
 737
 738         file = filter_obj_open(obd, md->lmd_object_id, S_IFREG);
 739         if (IS_ERR(file))
 740                 GOTO(out, retval = PTR_ERR(file));
 741
 742         /* count doubles as retval */
 743         for (pg = 0; pg < oa_bufs; pg++) {
 744                 CDEBUG(D_INODE, "OP %d obdo pgno: (%d) (%ld,"LPU64
 745                        ") off count ("LPU64",%d)\n",
 746                        cmd, pnum, file->f_dentry->d_inode->i_ino,
 747                        pga[pnum].off >> PAGE_CACHE_SHIFT, pga[pnum].off,
 748                        (int)pga[pnum].count);
 749                 if (cmd & OBD_BRW_WRITE) {
 750                         loff_t off;
 751                         char *buffer;
 752                         off = pga[pnum].off;
 753                         buffer = kmap(pga[pnum].pg);
 754                         retval = file->f_op->write(file, buffer,
 755                                                    pga[pnum].count,
 756                                                    &off);
 757                         kunmap(pga[pnum].pg);
 758                         CDEBUG(D_INODE, "retval %ld\n", retval);
 759                 } else {
 760                         loff_t off = pga[pnum].off;
 761                         char *buffer = kmap(pga[pnum].pg);
 762
 763                         if (off >= file->f_dentry->d_inode->i_size) {
 764                                 memset(buffer, 0, pga[pnum].count);
 765                                 retval = pga[pnum].count;
 766                         } else {
 767                                 retval = file->f_op->read(file, buffer,
 768                                                           pga[pnum].count, &off);
 769                         }
 770                         kunmap(pga[pnum].pg);
 771
 772                         if (retval != pga[pnum].count) {
 773                                 filp_close(file, 0);
 774                                 GOTO(out, retval = -EIO);
 775                         }
 776                         CDEBUG(D_INODE, "retval %ld\n", retval);
 777                 }
 778                 pnum++;
 779         }
 780         /* sizes and blocks are set by generic_file_write */
 781         /* ctimes/mtimes will follow with a setattr call */
 782         filp_close(file, 0);
 783
 784         /* XXX: do something with callback if it is set? */
 785
 786         EXIT;
 787 out:
 788         pop_ctxt(&saved);
 789         error = (retval >= 0) ? 0 : retval;
 790         return error;
 791 }
 792
 793 /*
 794  * Calculate the number of buffer credits needed to write multiple pages in
 795  * a single ext3/extN transaction.  No, this shouldn't be here, but as yet
 796  * ext3 doesn't have a nice API for calculating this sort of thing in advance.
 797  *
 798  * See comment above ext3_writepage_trans_blocks for details.  We assume
 799  * no data journaling is being done, but it does allow for all of the pages
 800  * being non-contiguous.  If we are guaranteed contiguous pages we could
 801  * reduce the number of (d)indirect blocks a lot.
 802  *
 803  * With N blocks per page and P pages, for each inode we have at most:
 804  * N*P indirect
 805  * min(N*P, blocksize/4 + 1) dindirect blocks
 806  * 1 tindirect
 807  *
 808  * For the entire filesystem, we have at most:
 809  * min(sum(nindir + P), ngroups) bitmap blocks (from the above)
 810  * min(sum(nindir + P), gdblocks) group descriptor blocks (from the above)
 811  * 1 inode block
 812  * 1 superblock
 813  * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quota files
 814  */
 815 static int ext3_credits_needed(struct super_block *sb, int objcount,
 816                                struct obd_ioobj *obj)
 817 {
 818         struct obd_ioobj *o = obj;
 819         int blockpp = 1 << (PAGE_CACHE_SHIFT - sb->s_blocksize_bits);
 820         int addrpp = EXT3_ADDR_PER_BLOCK(sb) * blockpp;
 821         int nbitmaps = 0;
 822         int ngdblocks = 0;
 823         int needed = objcount + 1;
 824         int i;
 825
 826         for (i = 0; i < objcount; i++, o++) {
 827                 int nblocks = o->ioo_bufcnt * blockpp;
 828                 int ndindirect = min(nblocks, addrpp + 1);
 829                 int nindir = nblocks + ndindirect + 1;
 830
 831                 nbitmaps += nindir + nblocks;
 832                 ngdblocks += nindir + nblocks;
 833
 834                 needed += nindir;
 835         }
 836
 837         if (nbitmaps > EXT3_SB(sb)->s_groups_count)
 838                 nbitmaps = EXT3_SB(sb)->s_groups_count;
 839         if (ngdblocks > EXT3_SB(sb)->s_gdb_count)
 840                 ngdblocks = EXT3_SB(sb)->s_gdb_count;
 841
 842         needed += nbitmaps + ngdblocks;
 843
 844 #ifdef CONFIG_QUOTA
 845         /* We assume that there will be 1 bit set in s_dquot.flags for each
 846          * quota file that is active.  This is at least true for now.
 847          */
 848         needed += hweight32(sb_any_quota_enabled(sb)) *
 849                 EXT3_SINGLEDATA_TRANS_BLOCKS;
 850 #endif
 851
 852         return needed;
 853 }
 854
 855 /* We have to start a huge journal transaction here to hold all of the
 856  * metadata for the pages being written here.  This is necessitated by
 857  * the fact that we do lots of prepare_write operations before we do
 858  * any of the matching commit_write operations, so even if we split
 859  * up to use "smaller" transactions none of them could complete until
 860  * all of them were opened.  By having a single journal transaction,
 861  * we eliminate duplicate reservations for common blocks like the
 862  * superblock and group descriptors or bitmaps.
 863  *
 864  * We will start the transaction here, but each prepare_write will
 865  * add a refcount to the transaction, and each commit_write will
 866  * remove a refcount.  The transaction will be closed when all of
 867  * the pages have been written.
 868  */
 869 static void *ext3_filter_journal_start(struct filter_obd *filter,
 870                                        int objcount, struct obd_ioobj *obj,
 871                                        int niocount, struct niobuf_remote *nb)
 872 {
 873         journal_t *journal = NULL;
 874         handle_t *handle = NULL;
 875         int needed;
 876
 877         /* Assumes ext3 and extN have same sb_info layout, but avoids issues
 878          * with having extN built properly before filterobd for now.
 879          */
 880         journal = EXT3_SB(filter->fo_sb)->s_journal;
 881         needed = ext3_credits_needed(filter->fo_sb, objcount, obj);
 882
 883         /* The number of blocks we could _possibly_ dirty can very large.
 884          * We reduce our request if it is absurd (and we couldn't get that
 885          * many credits for a single handle anyways).
 886          *
 887          * At some point we have to limit the size of I/Os sent at one time,
 888          * increase the size of the journal, or we have to calculate the
 889          * actual journal requirements more carefully by checking all of
 890          * the blocks instead of being maximally pessimistic.  It remains to
 891          * be seen if this is a real problem or not.
 892          */
 893         if (needed > journal->j_max_transaction_buffers) {
 894                 CERROR("want too many journal credits (%d) using %d instead\n",
 895                        needed, journal->j_max_transaction_buffers);
 896                 needed = journal->j_max_transaction_buffers;
 897         }
 898
 899         handle = journal_start(journal, needed);
 900         if (IS_ERR(handle))
 901                 CERROR("can't get handle for %d credits: rc = %ld\n", needed,
 902                        PTR_ERR(handle));
 903
 904         return(handle);
 905 }
 906
 907 static void *filter_journal_start(void **journal_save,
 908                                   struct filter_obd *filter,
 909                                   int objcount, struct obd_ioobj *obj,
 910                                   int niocount, struct niobuf_remote *nb)
 911 {
 912         void *handle = NULL;
 913
 914         /* This may not be necessary - we probably never have a
 915          * transaction started when we enter here, so we can
 916          * remove the saving of the journal state entirely.
 917          * For now leave it in just to see if it ever happens.
 918          */
 919         *journal_save = current->journal_info;
 920         if (*journal_save) {
 921                 CERROR("Already have handle %p???\n", *journal_save);
 922                 LBUG();
 923                 current->journal_info = NULL;
 924         }
 925
 926         if (!strcmp(filter->fo_fstype, "ext3") ||
 927             !strcmp(filter->fo_fstype, "extN"))
 928                 handle = ext3_filter_journal_start(filter, objcount, obj,
 929                                                    niocount, nb);
 930         return handle;
 931 }
 932
 933 static int ext3_filter_journal_stop(void *handle)
 934 {
 935         int rc;
 936
 937         /* We got a refcount on the handle for each call to prepare_write,
 938          * so we can drop the "parent" handle here to avoid the need for
 939          * osc to call back into filterobd to close the handle.  The
 940          * remaining references will be dropped in commit_write.
 941          */
 942         rc = journal_stop((handle_t *)handle);
 943
 944         return rc;
 945 }
 946
 947 static int filter_journal_stop(void *journal_save, struct filter_obd *filter,
 948                                void *handle)
 949 {
 950         int rc = 0;
 951
 952         if (!strcmp(filter->fo_fstype, "ext3") ||
 953             !strcmp(filter->fo_fstype, "extN"))
 954                 rc = ext3_filter_journal_stop(handle);
 955
 956         if (rc)
 957                 CERROR("error on journal stop: rc = %d\n", rc);
 958
 959         current->journal_info = journal_save;
 960
 961         return rc;
 962 }
 963
 964 static inline void lustre_put_page(struct page *page)
 965 {
 966         kunmap(page);
 967         page_cache_release(page);
 968 }
 969
 970 static struct page *
 971 lustre_get_page_read(struct inode *inode, unsigned long index)
 972 {
 973         struct address_space *mapping = inode->i_mapping;
 974         struct page *page;
 975         int rc;
 976
 977         page = read_cache_page(mapping, index,
 978                                (filler_t*)mapping->a_ops->readpage, NULL);
 979         if (!IS_ERR(page)) {
 980                 wait_on_page(page);
 981                 kmap(page);
 982                 if (!Page_Uptodate(page)) {
 983                         CERROR("page index %lu not uptodate\n", index);
 984                         GOTO(err_page, rc = -EIO);
 985                 }
 986                 if (PageError(page)) {
 987                         CERROR("page index %lu has error\n", index);
 988                         GOTO(err_page, rc = -EIO);
 989                 }
 990         }
 991         return page;
 992
 993 err_page:
 994         lustre_put_page(page);
 995         return ERR_PTR(rc);
 996 }
 997
 998 static struct page *
 999 lustre_get_page_write(struct inode *inode, unsigned long index)
1000 {
1001         struct address_space *mapping = inode->i_mapping;
1002         struct page *page;
1003         int rc;
1004
1005         page = grab_cache_page(mapping, index); /* locked page */
1006
1007         if (!IS_ERR(page)) {
1008                 kmap(page);
1009                 /* Note: Called with "O" and "PAGE_SIZE" this is essentially
1010                  * a no-op for most filesystems, because we write the whole
1011                  * page.  For partial-page I/O this will read in the page.
1012                  */
1013                 rc = mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
1014                 if (rc) {
1015                         CERROR("page index %lu, rc = %d\n", index, rc);
1016                         if (rc != -ENOSPC)
1017                                 LBUG();
1018                         GOTO(err_unlock, rc);
1019                 }
1020                 /* XXX not sure if we need this if we are overwriting page */
1021                 if (PageError(page)) {
1022                         CERROR("error on page index %lu, rc = %d\n", index, rc);
1023                         LBUG();
1024                         GOTO(err_unlock, rc = -EIO);
1025                 }
1026         }
1027         return page;
1028
1029 err_unlock:
1030         unlock_page(page);
1031         lustre_put_page(page);
1032         return ERR_PTR(rc);
1033 }
1034
1035 static int lustre_commit_write(struct page *page, unsigned from, unsigned to)
1036 {
1037         struct inode *inode = page->mapping->host;
1038         int err;
1039
1040         err = page->mapping->a_ops->commit_write(NULL, page, from, to);
1041         if (!err && IS_SYNC(inode))
1042                 err = waitfor_one_page(page);
1043
1044         //SetPageUptodate(page); // the client commit_write will do this
1045
1046         SetPageReferenced(page);
1047         unlock_page(page);
1048         lustre_put_page(page);
1049         return err;
1050 }
1051
1052 struct page *filter_get_page_write(struct inode *inode, unsigned long index,
1053                                    struct niobuf_local *lnb, int *pglocked)
1054 {
1055         struct address_space *mapping = inode->i_mapping;
1056         struct page *page;
1057         int rc;
1058
1059         //ASSERT_PAGE_INDEX(index, GOTO(err, rc = -EINVAL));
1060         if (*pglocked)
1061                 page = grab_cache_page_nowait(mapping, index); /* locked page */
1062         else
1063                 page = grab_cache_page(mapping, index); /* locked page */
1064
1065
1066         /* This page is currently locked, so get a temporary page instead. */
1067         /* XXX I believe this is a very dangerous thing to do - consider if
1068          *     we had multiple writers for the same file (definitely the case
1069          *     if we are using this codepath).  If writer A locks the page,
1070          *     writer B writes to a copy (as here), writer A drops the page
1071          *     lock, and writer C grabs the lock before B does, then B will
1072          *     later overwrite the data from C, even if C had LDLM locked
1073          *     and initiated the write after B did.
1074          */
1075         if (!page) {
1076                 unsigned long addr;
1077                 CDEBUG(D_PAGE, "ino %ld page %ld locked\n", inode->i_ino,index);
1078                 addr = __get_free_pages(GFP_KERNEL, 0); /* locked page */
1079                 if (!addr) {
1080                         CERROR("no memory for a temp page\n");
1081                         LBUG();
1082                         GOTO(err, rc = -ENOMEM);
1083                 }
1084                 page = virt_to_page(addr);
1085                 kmap(page);
1086                 page->index = index;
1087                 lnb->flags |= N_LOCAL_TEMP_PAGE;
1088         } else if (!IS_ERR(page)) {
1089                 (*pglocked)++;
1090                 kmap(page);
1091
1092                 /* Note: Called with "O" and "PAGE_SIZE" this is essentially
1093                  * a no-op for most filesystems, because we write the whole
1094                  * page.  For partial-page I/O this will read in the page.
1095                  */
1096                 rc = mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
1097                 if (rc) {
1098                         CERROR("page index %lu, rc = %d\n", index, rc);
1099                         if (rc != -ENOSPC)
1100                                 LBUG();
1101                         GOTO(err_unlock, rc);
1102                 }
1103                 /* XXX not sure if we need this if we are overwriting page */
1104                 if (PageError(page)) {
1105                         CERROR("error on page index %lu, rc = %d\n", index, rc);
1106                         LBUG();
1107                         GOTO(err_unlock, rc = -EIO);
1108                 }
1109         }
1110         return page;
1111
1112 err_unlock:
1113         unlock_page(page);
1114         lustre_put_page(page);
1115 err:
1116         return ERR_PTR(rc);
1117 }
1118
1119 /*
1120  * We need to balance prepare_write() calls with commit_write() calls.
1121  * If the page has been prepared, but we have no data for it, we don't
1122  * want to overwrite valid data on disk, but we still need to zero out
1123  * data for space which was newly allocated.  Like part of what happens
1124  * in __block_prepare_write() for newly allocated blocks.
1125  *
1126  * XXX currently __block_prepare_write() creates buffers for all the
1127  *     pages, and the filesystems mark these buffers as BH_New if they
1128  *     were newly allocated from disk. We use the BH_New flag similarly.
1129  */
1130 static int filter_commit_write(struct page *page, unsigned from, unsigned to,
1131                                int err)
1132 {
1133         if (err) {
1134                 unsigned block_start, block_end;
1135                 struct buffer_head *bh, *head = page->buffers;
1136                 unsigned blocksize = head->b_size;
1137                 void *addr = page_address(page);
1138
1139                 /* debugging: just seeing if this ever happens */
1140                 CERROR("called filter_commit_write for obj %ld:%ld on err %d\n",
1141                        page->index, page->mapping->host->i_ino, err);
1142
1143                 /* Currently one buffer per page, but in the future... */
1144                 for (bh = head, block_start = 0; bh != head || !block_start;
1145                      block_start = block_end, bh = bh->b_this_page) {
1146                         block_end = block_start + blocksize;
1147                         if (buffer_new(bh))
1148                                 memset(addr + block_start, 0, blocksize);
1149                 }
1150         }
1151
1152         return lustre_commit_write(page, from, to);
1153 }
1154
1155 static int filter_preprw(int cmd, struct lustre_handle *conn,
1156                          int objcount, struct obd_ioobj *obj,
1157                          int niocount, struct niobuf_remote *nb,
1158                          struct niobuf_local *res, void **desc_private)
1159 {
1160         struct obd_run_ctxt saved;
1161         struct obd_device *obd;
1162         struct obd_ioobj *o = obj;
1163         struct niobuf_remote *b = nb;
1164         struct niobuf_local *r = res;
1165         void *journal_save = NULL;
1166         int pglocked = 0;
1167         int rc = 0;
1168         int i;
1169         ENTRY;
1170
1171         obd = class_conn2obd(conn);
1172         if (!obd) {
1173                 CDEBUG(D_IOCTL, "invalid client "LPX64"\n", conn->addr);
1174                 RETURN(-EINVAL);
1175         }
1176         memset(res, 0, sizeof(*res) * niocount);
1177
1178         push_ctxt(&saved, &obd->u.filter.fo_ctxt);
1179
1180         if (cmd & OBD_BRW_WRITE) {
1181                 *desc_private = filter_journal_start(&journal_save,
1182                                                      &obd->u.filter,
1183                                                      objcount, obj, niocount,
1184                                                      nb);
1185                 if (IS_ERR(*desc_private))
1186                         GOTO(out_ctxt, rc = PTR_ERR(*desc_private));
1187         }
1188
1189         for (i = 0; i < objcount; i++, o++) {
1190                 struct dentry *dentry;
1191                 struct inode *inode;
1192                 int j;
1193
1194                 dentry = filter_fid2dentry(obd, filter_parent(obd, S_IFREG),
1195                                            o->ioo_id, S_IFREG);
1196                 if (IS_ERR(dentry))
1197                         GOTO(out_clean, rc = PTR_ERR(dentry));
1198                 inode = dentry->d_inode;
1199                 if (!inode) {
1200                         CERROR("trying to BRW to non-existent file %Ld\n",
1201                                (unsigned long long)o->ioo_id);
1202                         f_dput(dentry);
1203                         GOTO(out_clean, rc = -ENOENT);
1204                 }
1205
1206                 for (j = 0; j < o->ioo_bufcnt; j++, b++, r++) {
1207                         unsigned long index = b->offset >> PAGE_SHIFT;
1208                         struct page *page;
1209
1210                         if (j == 0)
1211                                 r->dentry = dentry;
1212                         else
1213                                 r->dentry = dget(dentry);
1214
1215                         if (cmd & OBD_BRW_WRITE)
1216                                 page = filter_get_page_write(inode, index, r,
1217                                                              &pglocked);
1218                         else
1219                                 page = lustre_get_page_read(inode, index);
1220
1221                         if (IS_ERR(page)) {
1222                                 f_dput(dentry);
1223                                 GOTO(out_clean, rc = PTR_ERR(page));
1224                         }
1225
1226                         r->addr = page_address(page);
1227                         r->offset = b->offset;
1228                         r->page = page;
1229                         r->len = b->len;
1230                 }
1231         }
1232
1233 out_stop:
1234         if (cmd & OBD_BRW_WRITE) {
1235                 int err = filter_journal_stop(journal_save, &obd->u.filter,
1236                                               *desc_private);
1237                 if (!rc)
1238                         rc = err;
1239         }
1240 out_ctxt:
1241         pop_ctxt(&saved);
1242         RETURN(rc);
1243 out_clean:
1244         while (r-- > res) {
1245                 CERROR("error cleanup on brw\n");
1246                 f_dput(r->dentry);
1247                 if (cmd & OBD_BRW_WRITE)
1248                         filter_commit_write(r->page, 0, PAGE_SIZE, rc);
1249                 else
1250                         lustre_put_page(r->page);
1251         }
1252         goto out_stop;
1253 }
1254
1255 static int filter_write_locked_page(struct niobuf_local *lnb)
1256 {
1257         struct page *lpage;
1258         int rc;
1259
1260         lpage = lustre_get_page_write(lnb->dentry->d_inode, lnb->page->index);
1261         if (IS_ERR(lpage)) {
1262                 /* It is highly unlikely that we would ever get an error here.
1263                  * The page we want to get was previously locked, so it had to
1264                  * have already allocated the space, and we were just writing
1265                  * over the same data, so there would be no hole in the file.
1266                  *
1267                  * XXX: possibility of a race with truncate could exist, need
1268                  *      to check that.  There are no guarantees w.r.t.
1269                  *      write order even on a local filesystem, although the
1270                  *      normal response would be to return the number of bytes
1271                  *      successfully written and leave the rest to the app.
1272                  */
1273                 rc = PTR_ERR(lpage);
1274                 CERROR("error getting locked page index %ld: rc = %d\n",
1275                        lnb->page->index, rc);
1276                 GOTO(out, rc);
1277         }
1278
1279         /* lpage is kmapped in lustre_get_page_write() above and kunmapped in
1280          * lustre_commit_write() below, lnb->page was kmapped previously in
1281          * filter_get_page_write() and kunmapped in lustre_put_page() below.
1282          */
1283         memcpy(page_address(lpage), page_address(lnb->page), PAGE_SIZE);
1284         rc = lustre_commit_write(lpage, 0, PAGE_SIZE);
1285         if (rc)
1286                 CERROR("error committing locked page %ld: rc = %d\n",
1287                        lnb->page->index, rc);
1288 out:
1289         lustre_put_page(lnb->page);
1290
1291         return rc;
1292 }
1293
1294 static int filter_commitrw(int cmd, struct lustre_handle *conn,
1295                            int objcount, struct obd_ioobj *obj,
1296                            int niocount, struct niobuf_local *res,
1297                            void *private)
1298 {
1299         struct obd_run_ctxt saved;
1300         struct obd_ioobj *o;
1301         struct niobuf_local *r;
1302         struct obd_device *obd = class_conn2obd(conn);
1303         void *journal_save;
1304         int found_locked = 0;
1305         int rc = 0;
1306         int i;
1307         ENTRY;
1308
1309         push_ctxt(&saved, &obd->u.filter.fo_ctxt);
1310         journal_save = current->journal_info;
1311         LASSERT(!journal_save);
1312
1313         current->journal_info = private;
1314         for (i = 0, o = obj, r = res; i < objcount; i++, o++) {
1315                 int j;
1316                 for (j = 0 ; j < o->ioo_bufcnt ; j++, r++) {
1317                         struct page *page = r->page;
1318
1319                         if (!page)
1320                                 LBUG();
1321
1322                         if (r->flags & N_LOCAL_TEMP_PAGE) {
1323                                 found_locked++;
1324                                 continue;
1325                         }
1326
1327                         if (cmd & OBD_BRW_WRITE) {
1328                                 int err = filter_commit_write(page, 0,
1329                                                               r->len, 0);
1330
1331                                 if (!rc)
1332                                         rc = err;
1333                         } else
1334                                 lustre_put_page(page);
1335
1336                         f_dput(r->dentry);
1337                 }
1338         }
1339         current->journal_info = journal_save;
1340
1341         if (!found_locked)
1342                 goto out_ctxt;
1343
1344         for (i = 0, o = obj, r = res; i < objcount; i++, o++) {
1345                 int j;
1346                 for (j = 0 ; j < o->ioo_bufcnt ; j++, r++) {
1347                         int err;
1348                         if (!(r->flags & N_LOCAL_TEMP_PAGE))
1349                                 continue;
1350
1351                         err = filter_write_locked_page(r);
1352                         if (!rc)
1353                                 rc = err;
1354                         f_dput(r->dentry);
1355                 }
1356         }
1357
1358 out_ctxt:
1359         pop_ctxt(&saved);
1360         RETURN(rc);
1361 }
1362
1363 static int filter_statfs(struct lustre_handle *conn, struct obd_statfs *osfs)
1364 {
1365         struct obd_device *obd = class_conn2obd(conn);
1366         struct statfs sfs;
1367         int rc;
1368
1369         ENTRY;
1370         rc = vfs_statfs(obd->u.filter.fo_sb, &sfs);
1371         if (!rc)
1372                 statfs_pack(osfs, &sfs);
1373
1374         return rc;
1375 }
1376
1377 static int filter_get_info(struct lustre_handle *conn, obd_count keylen,
1378                            void *key, obd_count *vallen, void **val)
1379 {
1380         struct obd_device *obd;
1381         ENTRY;
1382
1383         obd = class_conn2obd(conn);
1384         if (!obd) {
1385                 CDEBUG(D_IOCTL, "invalid client "LPX64"\n", conn->addr);
1386                 RETURN(-EINVAL);
1387         }
1388
1389         if ( keylen == strlen("blocksize") &&
1390              memcmp(key, "blocksize", keylen) == 0 ) {
1391                 *vallen = sizeof(long);
1392                 *val = (void *)(long)obd->u.filter.fo_sb->s_blocksize;
1393                 RETURN(0);
1394         }
1395
1396         if ( keylen == strlen("blocksize_bits") &&
1397              memcmp(key, "blocksize_bits", keylen) == 0 ){
1398                 *vallen = sizeof(long);
1399                 *val = (void *)(long)obd->u.filter.fo_sb->s_blocksize_bits;
1400                 RETURN(0);
1401         }
1402
1403         if ( keylen == strlen("root_ino") &&
1404              memcmp(key, "root_ino", keylen) == 0 ){
1405                 *vallen = sizeof(obd_id);
1406                 *val = (void *)(obd_id)FILTER_ROOTINO;
1407                 RETURN(0);
1408         }
1409
1410         CDEBUG(D_IOCTL, "invalid key\n");
1411         RETURN(-EINVAL);
1412 }
1413
1414 int filter_copy_data(struct lustre_handle *dst_conn, struct obdo *dst,
1415                   struct lustre_handle *src_conn, struct obdo *src,
1416                   obd_size count, obd_off offset)
1417 {
1418         struct page *page;
1419         struct lov_stripe_md srcmd, dstmd;
1420         unsigned long index = 0;
1421         int err = 0;
1422
1423         memset(&srcmd, 0, sizeof(srcmd));
1424         memset(&dstmd, 0, sizeof(dstmd));
1425         srcmd.lmd_object_id = src->o_id;
1426         dstmd.lmd_object_id = dst->o_id;
1427
1428         ENTRY;
1429         CDEBUG(D_INFO, "src: ino %Ld blocks %Ld, size %Ld, dst: ino %Ld\n",
1430                (unsigned long long)src->o_id, (unsigned long long)src->o_blocks,
1431                (unsigned long long)src->o_size, (unsigned long long)dst->o_id);
1432         page = alloc_page(GFP_USER);
1433         if (page == NULL)
1434                 RETURN(-ENOMEM);
1435
1436         while (TryLockPage(page))
1437                 ___wait_on_page(page);
1438
1439         /* XXX with brw vector I/O, we could batch up reads and writes here,
1440          *     all we need to do is allocate multiple pages to handle the I/Os
1441          *     and arrays to handle the request parameters.
1442          */
1443         while (index < ((src->o_size + PAGE_SIZE - 1) >> PAGE_SHIFT)) {
1444                 struct brw_page pg;
1445                 struct io_cb_data *cbd = ll_init_cb();
1446
1447                 if (!cbd) {
1448                         err = -ENOMEM;
1449                         EXIT;
1450                         break;
1451                 }
1452
1453                 pg.pg = page;
1454                 pg.count = PAGE_SIZE;
1455                 pg.off = (page->index) << PAGE_SHIFT;
1456                 pg.flag = 0;
1457
1458                 page->index = index;
1459                 err = obd_brw(OBD_BRW_READ, src_conn, &srcmd, 1, &pg,
1460                               ll_sync_io_cb, cbd);
1461
1462                 if ( err ) {
1463                         EXIT;
1464                         break;
1465                 }
1466
1467                 cbd = ll_init_cb();
1468                 if (!cbd) {
1469                         err = -ENOMEM;
1470                         EXIT;
1471                         break;
1472                 }
1473                 pg.flag = OBD_BRW_CREATE;
1474                 CDEBUG(D_INFO, "Read page %ld ...\n", page->index);
1475
1476                 err = obd_brw(OBD_BRW_WRITE, dst_conn, &dstmd, 1, &pg,
1477                               ll_sync_io_cb, cbd);
1478
1479                 /* XXX should handle dst->o_size, dst->o_blocks here */
1480                 if ( err ) {
1481                         EXIT;
1482                         break;
1483                 }
1484
1485                 CDEBUG(D_INFO, "Wrote page %ld ...\n", page->index);
1486
1487                 index++;
1488         }
1489         dst->o_size = src->o_size;
1490         dst->o_blocks = src->o_blocks;
1491         dst->o_valid |= OBD_MD_FLSIZE | OBD_MD_FLBLOCKS;
1492         unlock_page(page);
1493         __free_page(page);
1494
1495         RETURN(err);
1496 }
1497
1498
1499 static struct obd_ops filter_obd_ops = {
1500         o_get_info:    filter_get_info,
1501         o_setup:       filter_setup,
1502         o_cleanup:     filter_cleanup,
1503         o_connect:     filter_connect,
1504         o_disconnect:  filter_disconnect,
1505         o_statfs:      filter_statfs,
1506         o_getattr:     filter_getattr,
1507         o_create:      filter_create,
1508         o_setattr:     filter_setattr,
1509         o_destroy:     filter_destroy,
1510         o_open:        filter_open,
1511         o_close:       filter_close,
1512         o_brw:         filter_pgcache_brw,
1513         o_punch:       filter_truncate,
1514         o_preprw:      filter_preprw,
1515         o_commitrw:    filter_commitrw
1516 #if 0
1517         o_preallocate: filter_preallocate_inodes,
1518         o_migrate:     filter_migrate,
1519         o_copy:        filter_copy_data,
1520         o_iterate:     filter_iterate
1521 #endif
1522 };
1523
1524
1525 static int __init obdfilter_init(void)
1526 {
1527         printk(KERN_INFO "Filtering OBD driver  v0.001, info@clusterfs.com\n");
1528         return class_register_type(&filter_obd_ops, OBD_FILTER_DEVICENAME);
1529 }
1530
1531 static void __exit obdfilter_exit(void)
1532 {
1533         class_unregister_type(OBD_FILTER_DEVICENAME);
1534 }
1535
1536 MODULE_AUTHOR("Cluster File Systems, Inc. <info@clusterfs.com>");
1537 MODULE_DESCRIPTION("Lustre Filtering OBD driver v1.0");
1538 MODULE_LICENSE("GPL");
1539
1540 module_init(obdfilter_init);
1541 module_exit(obdfilter_exit);