lustre/obdclass/jobid.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2014, Intel Corporation.
  27  *
  28  * Copyright 2017 Cray Inc, all rights reserved.
  29  * Author: Ben Evans.
  30  *
  31  * Store PID->JobID mappings
  32  */
  33
  34 #define DEBUG_SUBSYSTEM S_RPC
  35 #include <linux/user_namespace.h>
  36 #include <linux/uidgid.h>
  37 #include <linux/utsname.h>
  38
  39 #include <libcfs/libcfs.h>
  40 #include <obd_support.h>
  41 #include <obd_class.h>
  42 #include <lustre_net.h>
  43
  44 static struct cfs_hash *jobid_hash;
  45 static struct cfs_hash_ops jobid_hash_ops;
  46 spinlock_t jobid_hash_lock;
  47
  48 #define RESCAN_INTERVAL 30
  49 #define DELETE_INTERVAL 300
  50
  51 char obd_jobid_var[JOBSTATS_JOBID_VAR_MAX_LEN + 1] = JOBSTATS_DISABLE;
  52 char obd_jobid_name[LUSTRE_JOBID_SIZE] = "%e.%u";
  53
  54 /**
  55  * Structure to store a single PID->JobID mapping
  56  */
  57 struct jobid_pid_map {
  58         struct hlist_node       jp_hash;
  59         time64_t                jp_time;
  60         spinlock_t              jp_lock; /* protects jp_jobid */
  61         char                    jp_jobid[LUSTRE_JOBID_SIZE];
  62         unsigned int            jp_joblen;
  63         atomic_t                jp_refcount;
  64         pid_t                   jp_pid;
  65 };
  66
  67 /*
  68  * Jobid can be set for a session (see setsid(2)) by writing to
  69  * a sysfs file from any process in that session.
  70  * The jobids are stored in a hash table indexed by the relevant
  71  * struct pid.  We periodically look for entries where the pid has
  72  * no PIDTYPE_SID tasks any more, and prune them.  This happens within
  73  * 5 seconds of a jobid being added, and every 5 minutes when jobids exist,
  74  * but none are added.
  75  */
  76 #define JOBID_EXPEDITED_CLEAN (5)
  77 #define JOBID_BACKGROUND_CLEAN (5 * 60)
  78
  79 struct session_jobid {
  80         struct pid              *sj_session;
  81         struct rhash_head       sj_linkage;
  82         struct rcu_head         sj_rcu;
  83         char                    sj_jobid[1];
  84 };
  85
  86 static const struct rhashtable_params jobid_params = {
  87         .key_len        = sizeof(struct pid *),
  88         .key_offset     = offsetof(struct session_jobid, sj_session),
  89         .head_offset    = offsetof(struct session_jobid, sj_linkage),
  90 };
  91
  92 static struct rhashtable session_jobids;
  93
  94 /*
  95  * jobid_current must be called with rcu_read_lock held.
  96  * if it returns non-NULL, the string can only be used
  97  * until rcu_read_unlock is called.
  98  */
  99 char *jobid_current(void)
 100 {
 101         struct pid *sid = task_session(current);
 102         struct session_jobid *sj;
 103
 104         sj = rhashtable_lookup_fast(&session_jobids, &sid, jobid_params);
 105         if (sj)
 106                 return sj->sj_jobid;
 107         return NULL;
 108 }
 109
 110 static void jobid_prune_expedite(void);
 111 /*
 112  * jobid_set_current will try to add a new entry
 113  * to the table.  If one exists with the same key, the
 114  * jobid will be replaced
 115  */
 116 int jobid_set_current(char *jobid)
 117 {
 118         struct pid *sid;
 119         struct session_jobid *sj, *origsj;
 120         int ret;
 121         int len = strlen(jobid);
 122
 123         sj = kmalloc(sizeof(*sj) + len, GFP_KERNEL);
 124         if (!sj)
 125                 return -ENOMEM;
 126         rcu_read_lock();
 127         sid = task_session(current);
 128         sj->sj_session = get_pid(sid);
 129         strncpy(sj->sj_jobid, jobid, len+1);
 130         origsj = rhashtable_lookup_get_insert_fast(&session_jobids,
 131                                                    &sj->sj_linkage,
 132                                                    jobid_params);
 133         if (origsj == NULL) {
 134                 /* successful insert */
 135                 rcu_read_unlock();
 136                 jobid_prune_expedite();
 137                 return 0;
 138         }
 139
 140         if (IS_ERR(origsj)) {
 141                 put_pid(sj->sj_session);
 142                 kfree(sj);
 143                 rcu_read_unlock();
 144                 return PTR_ERR(origsj);
 145         }
 146         ret = rhashtable_replace_fast(&session_jobids,
 147                                       &origsj->sj_linkage,
 148                                       &sj->sj_linkage,
 149                                       jobid_params);
 150         if (ret) {
 151                 put_pid(sj->sj_session);
 152                 kfree(sj);
 153                 rcu_read_unlock();
 154                 return ret;
 155         }
 156         put_pid(origsj->sj_session);
 157         rcu_read_unlock();
 158         kfree_rcu(origsj, sj_rcu);
 159         jobid_prune_expedite();
 160
 161         return 0;
 162 }
 163
 164 static void jobid_free(void *vsj, void *arg)
 165 {
 166         struct session_jobid *sj = vsj;
 167
 168         put_pid(sj->sj_session);
 169         kfree(sj);
 170 }
 171
 172 static void jobid_prune(struct work_struct *work);
 173 static DECLARE_DELAYED_WORK(jobid_prune_work, jobid_prune);
 174 static int jobid_prune_expedited;
 175 static void jobid_prune(struct work_struct *work)
 176 {
 177         int remaining = 0;
 178         struct rhashtable_iter iter;
 179         struct session_jobid *sj;
 180
 181         jobid_prune_expedited = 0;
 182         rhashtable_walk_enter(&session_jobids, &iter);
 183         rhashtable_walk_start(&iter);
 184         while ((sj = rhashtable_walk_next(&iter)) != NULL) {
 185                 if (IS_ERR(sj)) {
 186                         if (PTR_ERR(sj) == -EAGAIN)
 187                                 continue;
 188                         break;
 189                 }
 190                 if (!hlist_empty(&sj->sj_session->tasks[PIDTYPE_SID])) {
 191                         remaining++;
 192                         continue;
 193                 }
 194                 if (rhashtable_remove_fast(&session_jobids,
 195                                            &sj->sj_linkage,
 196                                            jobid_params) == 0) {
 197                         put_pid(sj->sj_session);
 198                         kfree_rcu(sj, sj_rcu);
 199                 }
 200         }
 201         rhashtable_walk_stop(&iter);
 202         rhashtable_walk_exit(&iter);
 203         if (remaining)
 204                 schedule_delayed_work(&jobid_prune_work,
 205                                       cfs_time_seconds(JOBID_BACKGROUND_CLEAN));
 206 }
 207
 208 static void jobid_prune_expedite(void)
 209 {
 210         if (!jobid_prune_expedited) {
 211                 jobid_prune_expedited = 1;
 212                 mod_delayed_work(system_wq, &jobid_prune_work,
 213                                  cfs_time_seconds(JOBID_EXPEDITED_CLEAN));
 214         }
 215 }
 216
 217 static int cfs_access_process_vm(struct task_struct *tsk,
 218                                  struct mm_struct *mm,
 219                                  unsigned long addr,
 220                                  void *buf, int len, int write)
 221 {
 222         /* Just copied from kernel for the kernels which doesn't
 223          * have access_process_vm() exported
 224          */
 225         struct vm_area_struct *vma;
 226         struct page *page;
 227         void *old_buf = buf;
 228
 229         /* Avoid deadlocks on mmap_sem if called from sys_mmap_pgoff(),
 230          * which is already holding mmap_sem for writes.  If some other
 231          * thread gets the write lock in the meantime, this thread will
 232          * block, but at least it won't deadlock on itself.  LU-1735
 233          */
 234         if (!mmap_read_trylock(mm))
 235                 return -EDEADLK;
 236
 237         /* ignore errors, just check how much was successfully transferred */
 238         while (len) {
 239                 int bytes, rc, offset;
 240                 void *maddr;
 241
 242 #if defined(HAVE_GET_USER_PAGES_GUP_FLAGS)
 243                 rc = get_user_pages(addr, 1, write ? FOLL_WRITE : 0, &page,
 244                                     &vma);
 245 #elif defined(HAVE_GET_USER_PAGES_6ARG)
 246                 rc = get_user_pages(addr, 1, write, 1, &page, &vma);
 247 #else
 248                 rc = get_user_pages(tsk, mm, addr, 1, write, 1, &page, &vma);
 249 #endif
 250                 if (rc <= 0)
 251                         break;
 252
 253                 bytes = len;
 254                 offset = addr & (PAGE_SIZE-1);
 255                 if (bytes > PAGE_SIZE-offset)
 256                         bytes = PAGE_SIZE-offset;
 257
 258                 maddr = kmap(page);
 259                 if (write) {
 260                         copy_to_user_page(vma, page, addr,
 261                                           maddr + offset, buf, bytes);
 262                         set_page_dirty_lock(page);
 263                 } else {
 264                         copy_from_user_page(vma, page, addr,
 265                                             buf, maddr + offset, bytes);
 266                 }
 267                 kunmap(page);
 268                 put_page(page);
 269                 len -= bytes;
 270                 buf += bytes;
 271                 addr += bytes;
 272         }
 273         mmap_read_unlock(mm);
 274
 275         return buf - old_buf;
 276 }
 277
 278 /* Read the environment variable of current process specified by @key. */
 279 static int cfs_get_environ(const char *key, char *value, int *val_len)
 280 {
 281         struct mm_struct *mm;
 282         char *buffer;
 283         int buf_len = PAGE_SIZE;
 284         int key_len = strlen(key);
 285         unsigned long addr;
 286         int rc;
 287         bool skip = false;
 288
 289         ENTRY;
 290         buffer = kmalloc(buf_len, GFP_USER);
 291         if (!buffer)
 292                 RETURN(-ENOMEM);
 293
 294         mm = get_task_mm(current);
 295         if (!mm) {
 296                 kfree(buffer);
 297                 RETURN(-EINVAL);
 298         }
 299
 300         addr = mm->env_start;
 301         while (addr < mm->env_end) {
 302                 int this_len, retval, scan_len;
 303                 char *env_start, *env_end;
 304
 305                 memset(buffer, 0, buf_len);
 306
 307                 this_len = min_t(int, mm->env_end - addr, buf_len);
 308                 retval = cfs_access_process_vm(current, mm, addr, buffer,
 309                                                this_len, 0);
 310                 if (retval < 0)
 311                         GOTO(out, rc = retval);
 312                 else if (retval != this_len)
 313                         break;
 314
 315                 addr += retval;
 316
 317                 /* Parse the buffer to find out the specified key/value pair.
 318                  * The "key=value" entries are separated by '\0'.
 319                  */
 320                 env_start = buffer;
 321                 scan_len = this_len;
 322                 while (scan_len) {
 323                         char *entry;
 324                         int entry_len;
 325
 326                         env_end = memscan(env_start, '\0', scan_len);
 327                         LASSERT(env_end >= env_start &&
 328                                 env_end <= env_start + scan_len);
 329
 330                         /* The last entry of this buffer cross the buffer
 331                          * boundary, reread it in next cycle.
 332                          */
 333                         if (unlikely(env_end - env_start == scan_len)) {
 334                                 /* Just skip the entry larger than page size,
 335                                  * it can't be jobID env variable.
 336                                  */
 337                                 if (unlikely(scan_len == this_len))
 338                                         skip = true;
 339                                 else
 340                                         addr -= scan_len;
 341                                 break;
 342                         } else if (unlikely(skip)) {
 343                                 skip = false;
 344                                 goto skip;
 345                         }
 346                         entry = env_start;
 347                         entry_len = env_end - env_start;
 348                         CDEBUG(D_INFO, "key: %s, entry: %s\n", key, entry);
 349
 350                         /* Key length + length of '=' */
 351                         if (entry_len > key_len + 1 &&
 352                             entry[key_len] == '='  &&
 353                             !memcmp(entry, key, key_len)) {
 354                                 entry += key_len + 1;
 355                                 entry_len -= key_len + 1;
 356
 357                                 /* The 'value' buffer passed in is too small.
 358                                  * Copy what fits, but return -EOVERFLOW.
 359                                  */
 360                                 if (entry_len >= *val_len) {
 361                                         memcpy(value, entry, *val_len);
 362                                         value[*val_len - 1] = 0;
 363                                         GOTO(out, rc = -EOVERFLOW);
 364                                 }
 365
 366                                 memcpy(value, entry, entry_len);
 367                                 *val_len = entry_len;
 368                                 GOTO(out, rc = 0);
 369                         }
 370 skip:
 371                         scan_len -= (env_end - env_start + 1);
 372                         env_start = env_end + 1;
 373                 }
 374         }
 375         GOTO(out, rc = -ENOENT);
 376
 377 out:
 378         mmput(mm);
 379         kfree((void *)buffer);
 380         return rc;
 381 }
 382
 383 /*
 384  * Get jobid of current process by reading the environment variable
 385  * stored in between the "env_start" & "env_end" of task struct.
 386  *
 387  * If some job scheduler doesn't store jobid in the "env_start/end",
 388  * then an upcall could be issued here to get the jobid by utilizing
 389  * the userspace tools/API. Then, the jobid must be cached.
 390  */
 391 int jobid_get_from_environ(char *jobid_var, char *jobid, int *jobid_len)
 392 {
 393         int rc;
 394
 395         rc = cfs_get_environ(jobid_var, jobid, jobid_len);
 396         if (!rc)
 397                 goto out;
 398
 399         if (rc == -EOVERFLOW) {
 400                 /* For the PBS_JOBID and LOADL_STEP_ID keys (which are
 401                  * variable length strings instead of just numbers), it
 402                  * might make sense to keep the unique parts for JobID,
 403                  * instead of just returning an error.  That means a
 404                  * larger temp buffer for cfs_get_environ(), then
 405                  * truncating the string at some separator to fit into
 406                  * the specified jobid_len.  Fix later if needed. */
 407                 static ktime_t printed;
 408
 409                 if (unlikely(ktime_to_ns(printed) == 0 ||
 410                              ktime_after(ktime_get(),
 411                                          ktime_add_ns(printed,
 412                                              3600ULL * 24 * NSEC_PER_SEC)))) {
 413                         LCONSOLE_WARN("jobid: '%s' value too large (%d)\n",
 414                                       obd_jobid_var, *jobid_len);
 415                         printed = ktime_get();
 416                 }
 417
 418                 rc = 0;
 419         } else {
 420                 CDEBUG_LIMIT((rc == -ENOENT || rc == -EINVAL ||
 421                               rc == -EDEADLK) ? D_INFO : D_ERROR,
 422                              "jobid: get '%s' failed: rc = %d\n",
 423                              obd_jobid_var, rc);
 424         }
 425
 426 out:
 427         return rc;
 428 }
 429
 430 /*
 431  * jobid_should_free_item
 432  *
 433  * Each item is checked to see if it should be released
 434  * Removed from hash table by caller
 435  * Actually freed in jobid_put_locked
 436  *
 437  * Returns 1 if item is to be freed, 0 if it is to be kept
 438  */
 439
 440 static int jobid_should_free_item(void *obj, void *data)
 441 {
 442         char *jobid = data;
 443         struct jobid_pid_map *pidmap = obj;
 444         int rc = 0;
 445
 446         if (obj == NULL)
 447                 return 0;
 448
 449         if (jobid == NULL) {
 450                 WARN_ON_ONCE(atomic_read(&pidmap->jp_refcount) != 1);
 451                 return 1;
 452         }
 453
 454         spin_lock(&pidmap->jp_lock);
 455         /* prevent newly inserted items from deleting */
 456         if (jobid[0] == '\0' && atomic_read(&pidmap->jp_refcount) == 1)
 457                 rc = 1;
 458         else if (ktime_get_real_seconds() - pidmap->jp_time > DELETE_INTERVAL)
 459                 rc = 1;
 460         else if (strcmp(pidmap->jp_jobid, jobid) == 0)
 461                 rc = 1;
 462         spin_unlock(&pidmap->jp_lock);
 463
 464         return rc;
 465 }
 466
 467 /*
 468  * jobid_name_is_valid
 469  *
 470  * Checks if the jobid is a Lustre process
 471  *
 472  * Returns true if jobid is valid
 473  * Returns false if jobid looks like it's a Lustre process
 474  */
 475 static bool jobid_name_is_valid(char *jobid)
 476 {
 477         const char *const lustre_reserved[] = { "ll_ping", "ptlrpc",
 478                                                 "ldlm", "ll_sa", NULL };
 479         int i;
 480
 481         if (jobid[0] == '\0')
 482                 return false;
 483
 484         for (i = 0; lustre_reserved[i] != NULL; i++) {
 485                 if (strncmp(jobid, lustre_reserved[i],
 486                             strlen(lustre_reserved[i])) == 0)
 487                         return false;
 488         }
 489         return true;
 490 }
 491
 492 /*
 493  * jobid_get_from_cache()
 494  *
 495  * Returns contents of jobid_var from process environment for current PID,
 496  * or from the per-session jobid table.
 497  * Values fetch from process environment will be cached for some time to avoid
 498  * the overhead of scanning the environment.
 499  *
 500  * Return: -ENOMEM if allocating a new pidmap fails
 501  *         -ENOENT if no entry could be found
 502  *         +ve string length for success (something was returned in jobid)
 503  */
 504 static int jobid_get_from_cache(char *jobid, size_t joblen)
 505 {
 506         static time64_t last_expire;
 507         bool expire_cache = false;
 508         pid_t pid = current->pid;
 509         struct jobid_pid_map *pidmap = NULL;
 510         time64_t now = ktime_get_real_seconds();
 511         int rc = 0;
 512         ENTRY;
 513
 514         if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0) {
 515                 char *jid;
 516
 517                 rcu_read_lock();
 518                 jid = jobid_current();
 519                 if (jid) {
 520                         strlcpy(jobid, jid, joblen);
 521                         joblen = strlen(jobid);
 522                 } else {
 523                         rc = -ENOENT;
 524                 }
 525                 rcu_read_unlock();
 526                 GOTO(out, rc);
 527         }
 528
 529         LASSERT(jobid_hash != NULL);
 530
 531         /* scan hash periodically to remove old PID entries from cache */
 532         spin_lock(&jobid_hash_lock);
 533         if (unlikely(last_expire + DELETE_INTERVAL <= now)) {
 534                 expire_cache = true;
 535                 last_expire = now;
 536         }
 537         spin_unlock(&jobid_hash_lock);
 538
 539         if (expire_cache)
 540                 cfs_hash_cond_del(jobid_hash, jobid_should_free_item,
 541                                   "intentionally_bad_jobid");
 542
 543         /* first try to find PID in the hash and use that value */
 544         pidmap = cfs_hash_lookup(jobid_hash, &pid);
 545         if (pidmap == NULL) {
 546                 struct jobid_pid_map *pidmap2;
 547
 548                 OBD_ALLOC_PTR(pidmap);
 549                 if (pidmap == NULL)
 550                         GOTO(out, rc = -ENOMEM);
 551
 552                 pidmap->jp_pid = pid;
 553                 pidmap->jp_time = 0;
 554                 pidmap->jp_jobid[0] = '\0';
 555                 spin_lock_init(&pidmap->jp_lock);
 556                 INIT_HLIST_NODE(&pidmap->jp_hash);
 557                 /*
 558                  * @pidmap might be reclaimed just after it is added into
 559                  * hash list, init @jp_refcount as 1 to make sure memory
 560                  * could be not freed during access.
 561                  */
 562                 atomic_set(&pidmap->jp_refcount, 1);
 563
 564                 /*
 565                  * Add the newly created map to the hash, on key collision we
 566                  * lost a racing addition and must destroy our newly allocated
 567                  * map.  The object which exists in the hash will be returned.
 568                  */
 569                 pidmap2 = cfs_hash_findadd_unique(jobid_hash, &pid,
 570                                                   &pidmap->jp_hash);
 571                 if (unlikely(pidmap != pidmap2)) {
 572                         CDEBUG(D_INFO, "jobid: duplicate found for PID=%u\n",
 573                                pid);
 574                         OBD_FREE_PTR(pidmap);
 575                         pidmap = pidmap2;
 576                 }
 577         }
 578
 579         /*
 580          * If pidmap is old (this is always true for new entries) refresh it.
 581          * If obd_jobid_var is not found, cache empty entry and try again
 582          * later, to avoid repeat lookups for PID if obd_jobid_var missing.
 583          */
 584         spin_lock(&pidmap->jp_lock);
 585         if (pidmap->jp_time + RESCAN_INTERVAL <= now) {
 586                 char env_jobid[LUSTRE_JOBID_SIZE] = "";
 587                 int env_len = sizeof(env_jobid);
 588
 589                 pidmap->jp_time = now;
 590
 591                 spin_unlock(&pidmap->jp_lock);
 592                 rc = jobid_get_from_environ(obd_jobid_var, env_jobid, &env_len);
 593
 594                 CDEBUG(D_INFO, "jobid: PID mapping established: %d->%s\n",
 595                        pidmap->jp_pid, env_jobid);
 596                 spin_lock(&pidmap->jp_lock);
 597                 if (!rc) {
 598                         pidmap->jp_joblen = env_len;
 599                         strlcpy(pidmap->jp_jobid, env_jobid,
 600                                 sizeof(pidmap->jp_jobid));
 601                         rc = 0;
 602                 } else if (rc == -ENOENT) {
 603                         /* It might have been deleted, clear out old entry */
 604                         pidmap->jp_joblen = 0;
 605                         pidmap->jp_jobid[0] = '\0';
 606                 }
 607         }
 608
 609         /*
 610          * Regardless of how pidmap was found, if it contains a valid entry
 611          * use that for now.  If there was a technical error (e.g. -ENOMEM)
 612          * use the old cached value until it can be looked up again properly.
 613          * If a cached missing entry was found, return -ENOENT.
 614          */
 615         if (pidmap->jp_joblen) {
 616                 strlcpy(jobid, pidmap->jp_jobid, joblen);
 617                 joblen = pidmap->jp_joblen;
 618                 rc = 0;
 619         } else if (!rc) {
 620                 rc = -ENOENT;
 621         }
 622         spin_unlock(&pidmap->jp_lock);
 623
 624         cfs_hash_put(jobid_hash, &pidmap->jp_hash);
 625
 626         EXIT;
 627 out:
 628         return rc < 0 ? rc : joblen;
 629 }
 630
 631 /*
 632  * jobid_interpret_string()
 633  *
 634  * Interpret the jobfmt string to expand specified fields, like coredumps do:
 635  *   %e = executable
 636  *   %g = gid
 637  *   %h = hostname
 638  *   %H = short hostname
 639  *   %j = jobid from environment
 640  *   %p = pid
 641  *   %u = uid
 642  *
 643  * Unknown escape strings are dropped.  Other characters are copied through,
 644  * excluding whitespace (to avoid making jobid parsing difficult).
 645  *
 646  * Return: -EOVERFLOW if the expanded string does not fit within @joblen
 647  *         0 for success
 648  */
 649 static int jobid_interpret_string(const char *jobfmt, char *jobid,
 650                                   ssize_t joblen)
 651 {
 652         char c;
 653
 654         while ((c = *jobfmt++) && joblen > 1) {
 655                 char f, *p;
 656                 int l;
 657
 658                 if (isspace(c)) /* Don't allow embedded spaces */
 659                         continue;
 660
 661                 if (c != '%') {
 662                         *jobid = c;
 663                         joblen--;
 664                         jobid++;
 665                         *jobid = '\0';
 666                         continue;
 667                 }
 668
 669                 switch ((f = *jobfmt++)) {
 670                 case 'e': /* executable name */
 671                         l = snprintf(jobid, joblen, "%s", current->comm);
 672                         break;
 673                 case 'g': /* group ID */
 674                         l = snprintf(jobid, joblen, "%u",
 675                                      from_kgid(&init_user_ns, current_fsgid()));
 676                         break;
 677                 case 'h': /* hostname */
 678                         l = snprintf(jobid, joblen, "%s",
 679                                      init_utsname()->nodename);
 680                         break;
 681                 case 'H': /* short hostname. Cut at first dot */
 682                         l = snprintf(jobid, joblen, "%s",
 683                                      init_utsname()->nodename);
 684                         p = strnchr(jobid, joblen, '.');
 685                         if (p) {
 686                                 *p = '\0';
 687                                 l = p - jobid;
 688                         }
 689                         break;
 690                 case 'j': /* jobid stored in process environment */
 691                         l = jobid_get_from_cache(jobid, joblen);
 692                         if (l < 0)
 693                                 l = 0;
 694                         break;
 695                 case 'p': /* process ID */
 696                         l = snprintf(jobid, joblen, "%u", current->pid);
 697                         break;
 698                 case 'u': /* user ID */
 699                         l = snprintf(jobid, joblen, "%u",
 700                                      from_kuid(&init_user_ns, current_fsuid()));
 701                         break;
 702                 case '\0': /* '%' at end of format string */
 703                         l = 0;
 704                         goto out;
 705                 default: /* drop unknown %x format strings */
 706                         l = 0;
 707                         break;
 708                 }
 709                 jobid += l;
 710                 joblen -= l;
 711         }
 712         /*
 713          * This points at the end of the buffer, so long as jobid is always
 714          * incremented the same amount as joblen is decremented.
 715          */
 716 out:
 717         jobid[joblen - 1] = '\0';
 718
 719         return joblen < 0 ? -EOVERFLOW : 0;
 720 }
 721
 722 /*
 723  * Hash initialization, copied from server-side job stats bucket sizes
 724  */
 725 #define HASH_JOBID_BKT_BITS 5
 726 #define HASH_JOBID_CUR_BITS 7
 727 #define HASH_JOBID_MAX_BITS 12
 728
 729 int jobid_cache_init(void)
 730 {
 731         int rc = 0;
 732         ENTRY;
 733
 734         if (jobid_hash)
 735                 return 0;
 736
 737         spin_lock_init(&jobid_hash_lock);
 738         jobid_hash = cfs_hash_create("JOBID_HASH", HASH_JOBID_CUR_BITS,
 739                                      HASH_JOBID_MAX_BITS, HASH_JOBID_BKT_BITS,
 740                                      0, CFS_HASH_MIN_THETA, CFS_HASH_MAX_THETA,
 741                                      &jobid_hash_ops, CFS_HASH_DEFAULT);
 742         if (!jobid_hash) {
 743                 rc = -ENOMEM;
 744         } else {
 745                 rc = rhashtable_init(&session_jobids, &jobid_params);
 746                 if (rc) {
 747                         cfs_hash_putref(jobid_hash);
 748                         jobid_hash = NULL;
 749                 }
 750         }
 751
 752         RETURN(rc);
 753 }
 754 EXPORT_SYMBOL(jobid_cache_init);
 755
 756 void jobid_cache_fini(void)
 757 {
 758         struct cfs_hash *tmp_hash;
 759         ENTRY;
 760
 761         spin_lock(&jobid_hash_lock);
 762         tmp_hash = jobid_hash;
 763         jobid_hash = NULL;
 764         spin_unlock(&jobid_hash_lock);
 765
 766         cancel_delayed_work_sync(&jobid_prune_work);
 767
 768         if (tmp_hash != NULL) {
 769                 cfs_hash_cond_del(tmp_hash, jobid_should_free_item, NULL);
 770                 cfs_hash_putref(tmp_hash);
 771
 772                 rhashtable_free_and_destroy(&session_jobids, jobid_free, NULL);
 773         }
 774
 775
 776         EXIT;
 777 }
 778 EXPORT_SYMBOL(jobid_cache_fini);
 779
 780 /*
 781  * Hash operations for pid<->jobid
 782  */
 783 static unsigned jobid_hashfn(struct cfs_hash *hs, const void *key,
 784                              unsigned mask)
 785 {
 786         return cfs_hash_djb2_hash(key, sizeof(pid_t), mask);
 787 }
 788
 789 static void *jobid_key(struct hlist_node *hnode)
 790 {
 791         struct jobid_pid_map *pidmap;
 792
 793         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 794         return &pidmap->jp_pid;
 795 }
 796
 797 static int jobid_keycmp(const void *key, struct hlist_node *hnode)
 798 {
 799         const pid_t *pid_key1;
 800         const pid_t *pid_key2;
 801
 802         LASSERT(key != NULL);
 803         pid_key1 = (pid_t *)key;
 804         pid_key2 = (pid_t *)jobid_key(hnode);
 805
 806         return *pid_key1 == *pid_key2;
 807 }
 808
 809 static void *jobid_object(struct hlist_node *hnode)
 810 {
 811         return hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 812 }
 813
 814 static void jobid_get(struct cfs_hash *hs, struct hlist_node *hnode)
 815 {
 816         struct jobid_pid_map *pidmap;
 817
 818         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 819
 820         atomic_inc(&pidmap->jp_refcount);
 821 }
 822
 823 static void jobid_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
 824 {
 825         struct jobid_pid_map *pidmap;
 826
 827         if (hnode == NULL)
 828                 return;
 829
 830         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 831         LASSERT(atomic_read(&pidmap->jp_refcount) > 0);
 832         if (atomic_dec_and_test(&pidmap->jp_refcount)) {
 833                 CDEBUG(D_INFO, "Freeing: %d->%s\n",
 834                        pidmap->jp_pid, pidmap->jp_jobid);
 835
 836                 OBD_FREE_PTR(pidmap);
 837         }
 838 }
 839
 840 static struct cfs_hash_ops jobid_hash_ops = {
 841         .hs_hash        = jobid_hashfn,
 842         .hs_keycmp      = jobid_keycmp,
 843         .hs_key         = jobid_key,
 844         .hs_object      = jobid_object,
 845         .hs_get         = jobid_get,
 846         .hs_put         = jobid_put_locked,
 847         .hs_put_locked  = jobid_put_locked,
 848 };
 849
 850 /**
 851  * Generate the job identifier string for this process for tracking purposes.
 852  *
 853  * Fill in @jobid string based on the value of obd_jobid_var:
 854  * JOBSTATS_DISABLE:      none
 855  * JOBSTATS_NODELOCAL:    content of obd_jobid_name (jobid_interpret_string())
 856  * JOBSTATS_PROCNAME_UID: process name/UID
 857  * JOBSTATS_SESSION       per-session value set by
 858  *                            /sys/fs/lustre/jobid_this_session
 859  * anything else:         look up obd_jobid_var in the processes environment
 860  *
 861  * Return -ve error number, 0 on success.
 862  */
 863 int lustre_get_jobid(char *jobid, size_t joblen)
 864 {
 865         int rc = 0;
 866         ENTRY;
 867
 868         if (unlikely(joblen < 2)) {
 869                 if (joblen == 1)
 870                         jobid[0] = '\0';
 871                 RETURN(-EINVAL);
 872         }
 873
 874         if (strcmp(obd_jobid_var, JOBSTATS_DISABLE) == 0) {
 875                 /* Jobstats isn't enabled */
 876                 memset(jobid, 0, joblen);
 877         } else if (strcmp(obd_jobid_var, JOBSTATS_NODELOCAL) == 0) {
 878                 /* Whole node dedicated to single job */
 879                 rc = jobid_interpret_string(obd_jobid_name, jobid, joblen);
 880         } else if (strcmp(obd_jobid_var, JOBSTATS_PROCNAME_UID) == 0) {
 881                 rc = jobid_interpret_string("%e.%u", jobid, joblen);
 882         } else if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0 ||
 883                    jobid_name_is_valid(current->comm)) {
 884                 /*
 885                  * per-process jobid wanted, either from environment or from
 886                  * per-session setting.
 887                  * If obd_jobid_name contains "%j" or if getting the per-process
 888                  * jobid directly fails, fall back to using obd_jobid_name.
 889                  */
 890                 rc = -EAGAIN;
 891                 if (!strnstr(obd_jobid_name, "%j", joblen))
 892                         rc = jobid_get_from_cache(jobid, joblen);
 893
 894                 /* fall back to jobid_name if jobid_var not available */
 895                 if (rc < 0) {
 896                         int rc2 = jobid_interpret_string(obd_jobid_name,
 897                                                          jobid, joblen);
 898                         if (!rc2)
 899                                 rc = 0;
 900                 }
 901         }
 902
 903         RETURN(rc);
 904 }
 905 EXPORT_SYMBOL(lustre_get_jobid);
 906
 907 /*
 908  * lustre_jobid_clear
 909  *
 910  * Search cache for JobID given by @find_jobid.
 911  * If any entries in the hash table match the value, they are removed
 912  */
 913 void lustre_jobid_clear(const char *find_jobid)
 914 {
 915         char jobid[LUSTRE_JOBID_SIZE];
 916         char *end;
 917
 918         if (jobid_hash == NULL)
 919                 return;
 920
 921         strlcpy(jobid, find_jobid, sizeof(jobid));
 922         /* trim \n off the end of the incoming jobid */
 923         end = strchr(jobid, '\n');
 924         if (end && *end == '\n')
 925                 *end = '\0';
 926
 927         CDEBUG(D_INFO, "Clearing Jobid: %s\n", jobid);
 928         cfs_hash_cond_del(jobid_hash, jobid_should_free_item, jobid);
 929
 930         CDEBUG(D_INFO, "%d items remain in jobID table\n",
 931                atomic_read(&jobid_hash->hs_count));
 932 }