lustre/llite/llite_gns.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2004 Cluster File Systems, Inc.
   5  *   Author: Phil Schwan <phil@clusterfs.com>
   6  *
   7  *   This file is part of Lustre, http://www.lustre.org.
   8  *
   9  *   Lustre is free software; you can redistribute it and/or
  10  *   modify it under the terms of version 2 of the GNU General Public
  11  *   License as published by the Free Software Foundation.
  12  *
  13  *   Lustre is distributed in the hope that it will be useful,
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *   GNU General Public License for more details.
  17  *
  18  *   You should have received a copy of the GNU General Public License
  19  *   along with Lustre; if not, write to the Free Software
  20  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #define DEBUG_SUBSYSTEM S_LLITE
  24
  25 #include <linux/fs.h>
  26 #include <linux/version.h>
  27 #include <asm/uaccess.h>
  28 #include <linux/file.h>
  29 #include <linux/kmod.h>
  30
  31 #include <linux/lustre_lite.h>
  32 #include "llite_internal.h"
  33
  34 /* After roughly how long should we remove an inactive mount? */
  35 #define GNS_MOUNT_TIMEOUT 120
  36 /* How often should the GNS timer look for mounts to cleanup? */
  37 #define GNS_TICK 30
  38
  39 int ll_finish_gns(struct ll_sb_info *sbi)
  40 {
  41         down(&sbi->ll_gns_sem);
  42         if (sbi->ll_gns_state != LL_GNS_STATE_MOUNTING) {
  43                 up(&sbi->ll_gns_sem);
  44                 CERROR("FINISH_GNS called on mount which was not expecting "
  45                        "completion.\n");
  46                 return -EINVAL;
  47         }
  48
  49         sbi->ll_gns_state = LL_GNS_STATE_FINISHED;
  50         up(&sbi->ll_gns_sem);
  51         complete(&sbi->ll_gns_completion);
  52
  53         return 0;
  54 }
  55
  56 /* Pass exactly one (1) page in; when this function returns "page" will point
  57  * somewhere into the middle of the page. */
  58 int fill_page_with_path(struct dentry *dentry, struct vfsmount *mnt,
  59                         char **pagep)
  60 {
  61         char *path = *pagep, *p;
  62
  63         path[PAGE_SIZE - 1] = '\0';
  64         p = path + PAGE_SIZE - 1;
  65
  66         while (1) {
  67                 if (p - path < dentry->d_name.len + 1)
  68                         return -ENAMETOOLONG;
  69                 if (dentry->d_name.name[0] != '/') {
  70                         p -= dentry->d_name.len;
  71                         memcpy(p, dentry->d_name.name, dentry->d_name.len);
  72                         p--;
  73                         *p = '/';
  74                 }
  75
  76                 dentry = dentry->d_parent;
  77                 if (dentry->d_parent == dentry) {
  78                         if (mnt->mnt_parent == mnt)
  79                                 break; /* finished walking up */
  80                         mnt = mntget(mnt);
  81                         dget(dentry);
  82                         while (dentry->d_parent == dentry &&
  83                                follow_up(&mnt, &dentry))
  84                                 ;
  85                         mntput(mnt);
  86                         dput(dentry);
  87                 }
  88         }
  89         *pagep = p;
  90         return 0;
  91 }
  92
  93 int ll_dir_process_mount_object(struct dentry *dentry, struct vfsmount *mnt)
  94 {
  95         struct ll_sb_info *sbi;
  96         struct file *mntinfo_fd = NULL;
  97         struct page *datapage = NULL, *pathpage;
  98         struct address_space *mapping;
  99         struct ll_dentry_data *lld = dentry->d_fsdata;
 100         struct dentry *dchild, *tmp_dentry;
 101         struct vfsmount *tmp_mnt;
 102         char *p, *path, *argv[4];
 103         int stage = 0, rc = 0;
 104         ENTRY;
 105
 106         if (mnt == NULL) {
 107                 CERROR("suid directory found, but no vfsmount available.\n");
 108                 RETURN(-1);
 109         }
 110
 111         LASSERT(dentry->d_inode != NULL);
 112         LASSERT(S_ISDIR(dentry->d_inode->i_mode));
 113         LASSERT(lld != NULL);
 114         sbi = ll_i2sbi(dentry->d_inode);
 115         LASSERT(sbi != NULL);
 116
 117         down(&sbi->ll_gns_sem);
 118         if (sbi->ll_gns_state == LL_GNS_STATE_MOUNTING) {
 119                 up(&sbi->ll_gns_sem);
 120                 wait_for_completion(&sbi->ll_gns_completion);
 121                 if (d_mountpoint(dentry))
 122                         RETURN(0);
 123                 RETURN(-1);
 124         }
 125         if (sbi->ll_gns_state == LL_GNS_STATE_FINISHED) {
 126                 /* we lost a race; just return */
 127                 up(&sbi->ll_gns_sem);
 128                 if (d_mountpoint(dentry))
 129                         RETURN(0);
 130                 RETURN(-1);
 131         }
 132         LASSERT(sbi->ll_gns_state == LL_GNS_STATE_IDLE);
 133         sbi->ll_gns_state = LL_GNS_STATE_MOUNTING;
 134         up(&sbi->ll_gns_sem);
 135
 136         /* We need to build an absolute pathname to pass to mount */
 137         pathpage = alloc_pages(GFP_HIGHUSER, 0);
 138         if (pathpage == NULL)
 139                 GOTO(cleanup, rc = -ENOMEM);
 140         path = kmap(pathpage);
 141         LASSERT(path != NULL);
 142         stage = 1;
 143         fill_page_with_path(dentry, mnt, &path);
 144
 145         dchild = lookup_one_len(".mntinfo", dentry, strlen(".mntinfo"));
 146         if (dchild == NULL || IS_ERR(dchild)) {
 147                 CERROR("Directory %*s is setuid, but without a mount object.\n",
 148                        dentry->d_name.len, dentry->d_name.name);
 149                 GOTO(cleanup, rc = -1);
 150         }
 151
 152         mntget(mnt);
 153
 154         mntinfo_fd = dentry_open(dchild, mnt, 0);
 155         if (IS_ERR(mntinfo_fd)) {
 156                 dput(dchild);
 157                 mntput(mnt);
 158                 GOTO(cleanup, rc = PTR_ERR(mntinfo_fd));
 159         }
 160         stage = 2;
 161
 162         if (mntinfo_fd->f_dentry->d_inode->i_size > PAGE_SIZE) {
 163                 CERROR("Mount object file is too big (%Ld)\n",
 164                        mntinfo_fd->f_dentry->d_inode->i_size);
 165                 GOTO(cleanup, rc = -1);
 166         }
 167         mapping = mntinfo_fd->f_dentry->d_inode->i_mapping;
 168         datapage = read_cache_page(mapping, 0,
 169                                    (filler_t *)mapping->a_ops->readpage,
 170                                    mntinfo_fd);
 171         if (IS_ERR(datapage))
 172                 GOTO(cleanup, rc = PTR_ERR(datapage));
 173
 174         p = kmap(datapage);
 175         LASSERT(p != NULL);
 176         stage = 3;
 177
 178         p[PAGE_SIZE - 1] = '\0';
 179
 180         fput(mntinfo_fd);
 181         mntinfo_fd = NULL;
 182
 183         argv[0] = "/usr/lib/lustre/gns-upcall.sh";
 184         argv[1] = p;
 185         argv[2] = path;
 186         argv[3] = NULL;
 187         rc = USERMODEHELPER(argv[0], argv, NULL);
 188
 189         if (rc != 0) {
 190                 CERROR("GNS mount failed: %d\n", rc);
 191                 GOTO(cleanup, rc);
 192         }
 193
 194         wait_for_completion(&sbi->ll_gns_completion);
 195         LASSERT(sbi->ll_gns_state == LL_GNS_STATE_FINISHED);
 196
 197         if (d_mountpoint(dentry)) {
 198                 /* successful follow_down will mntput and dput */
 199                 tmp_mnt = mntget(mnt);
 200                 tmp_dentry = dget(dentry);
 201                 rc = follow_down(&tmp_mnt, &tmp_dentry);
 202                 if (rc == 1) {
 203                         struct ll_sb_info *sbi = ll_s2sbi(dentry->d_sb);
 204                         spin_lock(&dcache_lock);
 205                         LASSERT(list_empty(&tmp_mnt->mnt_lustre_list));
 206                         list_add_tail(&tmp_mnt->mnt_lustre_list,
 207                                       &sbi->ll_mnt_list);
 208                         spin_unlock(&dcache_lock);
 209
 210                         tmp_mnt->mnt_last_used = jiffies;
 211
 212                         mntput(tmp_mnt);
 213                         dput(tmp_dentry);
 214                         rc = 0;
 215                 } else {
 216                         mntput(mnt);
 217                         dput(dentry);
 218                 }
 219         } else {
 220                 CERROR("Woke up from GNS mount, but no mountpoint in place.\n");
 221                 rc = -1;
 222         }
 223
 224         EXIT;
 225 cleanup:
 226         switch (stage) {
 227         case 3:
 228                 kunmap(datapage);
 229                 page_cache_release(datapage);
 230         case 2:
 231                 if (mntinfo_fd != NULL)
 232                         fput(mntinfo_fd);
 233         case 1:
 234                 kunmap(pathpage);
 235                 __free_pages(pathpage, 0);
 236         case 0:
 237                 down(&sbi->ll_gns_sem);
 238                 sbi->ll_gns_state = LL_GNS_STATE_IDLE;
 239                 up(&sbi->ll_gns_sem);
 240         }
 241         return rc;
 242 }
 243
 244 /* If timeout == 1, only remove the mounts which are properly aged.
 245  *
 246  * If timeout == 0, we are unmounting -- remove them all. */
 247 int ll_gns_umount_all(struct ll_sb_info *sbi, int timeout)
 248 {
 249         struct list_head kill_list = LIST_HEAD_INIT(kill_list);
 250         struct page *page = NULL;
 251         char *kpage = NULL, *path;
 252         int rc;
 253         ENTRY;
 254
 255         if (timeout == 0) {
 256                 page = alloc_pages(GFP_HIGHUSER, 0);
 257                 if (page == NULL)
 258                         RETURN(-ENOMEM);
 259                 kpage = kmap(page);
 260                 LASSERT(kpage != NULL);
 261         }
 262
 263         spin_lock(&dcache_lock);
 264         list_splice_init(&sbi->ll_mnt_list, &kill_list);
 265
 266         /* Walk the list in reverse order, and put them on the front of the
 267          * sbi list each iteration; this avoids list-ordering problems if we
 268          * race with another gns-mounting thread */
 269         while (!list_empty(&kill_list)) {
 270                 struct vfsmount *mnt =
 271                         list_entry(kill_list.prev, struct vfsmount,
 272                                    mnt_lustre_list);
 273                 mntget(mnt);
 274                 list_del_init(&mnt->mnt_lustre_list);
 275                 list_add(&mnt->mnt_lustre_list, &sbi->ll_mnt_list);
 276
 277                 if (timeout &&
 278                     jiffies - mnt->mnt_last_used < GNS_MOUNT_TIMEOUT * HZ) {
 279                         mntput(mnt);
 280                         continue;
 281                 }
 282                 spin_unlock(&dcache_lock);
 283
 284                 CDEBUG(D_INODE, "unmounting mnt %p from sbi %p\n", mnt, sbi);
 285
 286                 rc = do_umount(mnt, 0);
 287                 if (rc != 0 && page != NULL) {
 288                         int rc2;
 289                         path = kpage;
 290                         rc2 = fill_page_with_path(mnt->mnt_root, mnt, &path);
 291                         CERROR("GNS umount(%s): %d\n", rc2 == 0 ? path : "",
 292                                rc);
 293                 }
 294                 mntput(mnt);
 295                 spin_lock(&dcache_lock);
 296         }
 297         spin_unlock(&dcache_lock);
 298
 299         if (page != NULL) {
 300                 kunmap(page);
 301                 __free_pages(page, 0);
 302         }
 303         RETURN(0);
 304 }
 305
 306 static struct list_head gns_sbi_list = LIST_HEAD_INIT(gns_sbi_list);
 307 static struct semaphore gns_sem;
 308 static struct ptlrpc_thread gns_thread;
 309
 310 void ll_gns_timer_callback(unsigned long data)
 311 {
 312         struct ll_sb_info *sbi = (void *)data;
 313         ENTRY;
 314
 315         down(&gns_sem);
 316         if (list_empty(&sbi->ll_gns_sbi_head))
 317                 list_add(&sbi->ll_gns_sbi_head, &gns_sbi_list);
 318         up(&gns_sem);
 319         wake_up(&gns_thread.t_ctl_waitq);
 320         mod_timer(&sbi->ll_gns_timer, jiffies + GNS_TICK * HZ);
 321 }
 322
 323 static int gns_check_event(void)
 324 {
 325         int rc;
 326         down(&gns_sem);
 327         rc = !list_empty(&gns_sbi_list);
 328         up(&gns_sem);
 329         return rc;
 330 }
 331
 332 static int ll_gns_thread_main(void *arg)
 333 {
 334         unsigned long flags;
 335         ENTRY;
 336
 337         {
 338                 char name[sizeof(current->comm)];
 339                 snprintf(name, sizeof(name) - 1, "ll_gns");
 340                 kportal_daemonize(name);
 341         }
 342         SIGNAL_MASK_LOCK(current, flags);
 343         sigfillset(&current->blocked);
 344         RECALC_SIGPENDING;
 345         SIGNAL_MASK_UNLOCK(current, flags);
 346
 347         gns_thread.t_flags = SVC_RUNNING;
 348         wake_up(&gns_thread.t_ctl_waitq);
 349
 350         while ((gns_thread.t_flags & SVC_STOPPING) == 0) {
 351                 struct l_wait_info lwi = { 0 };
 352
 353                 l_wait_event(gns_thread.t_ctl_waitq, gns_check_event() ||
 354                              gns_thread.t_flags & SVC_STOPPING, &lwi);
 355
 356                 down(&gns_sem);
 357                 while (!list_empty(&gns_sbi_list)) {
 358                         struct ll_sb_info *sbi =
 359                                 list_entry(gns_sbi_list.prev, struct ll_sb_info,
 360                                            ll_gns_sbi_head);
 361                         list_del_init(&sbi->ll_gns_sbi_head);
 362                         ll_gns_umount_all(sbi, 1);
 363                 }
 364                 up(&gns_sem);
 365         }
 366
 367         gns_thread.t_flags = SVC_STOPPED;
 368         wake_up(&gns_thread.t_ctl_waitq);
 369
 370         RETURN(0);
 371 }
 372
 373 void ll_gns_add_timer(struct ll_sb_info *sbi)
 374 {
 375         mod_timer(&sbi->ll_gns_timer, jiffies + GNS_TICK * HZ);
 376 }
 377
 378 void ll_gns_del_timer(struct ll_sb_info *sbi)
 379 {
 380         del_timer(&sbi->ll_gns_timer);
 381 }
 382
 383 int ll_gns_start_thread(void)
 384 {
 385         struct l_wait_info lwi = { 0 };
 386         int rc;
 387
 388         LASSERT(gns_thread.t_flags == 0);
 389         sema_init(&gns_sem, 1);
 390
 391         init_waitqueue_head(&gns_thread.t_ctl_waitq);
 392         rc = kernel_thread(ll_gns_thread_main, NULL, CLONE_VM | CLONE_FILES);
 393         if (rc < 0) {
 394                 CERROR("cannot start thread: %d\n", rc);
 395                 return rc;
 396         }
 397         l_wait_event(gns_thread.t_ctl_waitq, gns_thread.t_flags & SVC_RUNNING,
 398                      &lwi);
 399         return 0;
 400 }
 401
 402 void ll_gns_stop_thread(void)
 403 {
 404         struct l_wait_info lwi = { 0 };
 405
 406         down(&gns_sem);
 407         gns_thread.t_flags = SVC_STOPPING;
 408         up(&gns_sem);
 409
 410         wake_up(&gns_thread.t_ctl_waitq);
 411         l_wait_event(gns_thread.t_ctl_waitq, gns_thread.t_flags & SVC_STOPPED,
 412                      &lwi);
 413         gns_thread.t_flags = 0;
 414 }