fs/nilfs2/ioctl.c

   1 /*
   2  * ioctl.c - NILFS ioctl operations.
   3  *
   4  * Copyright (C) 2007, 2008 Nippon Telegraph and Telephone Corporation.
   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 as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Koji Sato <koji@osrg.net>.
  21  */
  22
  23 #include <linux/fs.h>
  24 #include <linux/wait.h>
  25 #include <linux/slab.h>
  26 #include <linux/capability.h>   /* capable() */
  27 #include <linux/uaccess.h>      /* copy_from_user(), copy_to_user() */
  28 #include <linux/vmalloc.h>
  29 #include <linux/mount.h>        /* mnt_want_write(), mnt_drop_write() */
  30 #include <linux/nilfs2_fs.h>
  31 #include "nilfs.h"
  32 #include "segment.h"
  33 #include "bmap.h"
  34 #include "cpfile.h"
  35 #include "sufile.h"
  36 #include "dat.h"
  37
  38
  39 static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
  40                                  struct nilfs_argv *argv, int dir,
  41                                  ssize_t (*dofunc)(struct the_nilfs *,
  42                                                    __u64 *, int,
  43                                                    void *, size_t, size_t))
  44 {
  45         void *buf;
  46         void __user *base = (void __user *)(unsigned long)argv->v_base;
  47         size_t maxmembs, total, n;
  48         ssize_t nr;
  49         int ret, i;
  50         __u64 pos, ppos;
  51
  52         if (argv->v_nmembs == 0)
  53                 return 0;
  54
  55         if (argv->v_size > PAGE_SIZE)
  56                 return -EINVAL;
  57
  58         buf = (void *)__get_free_pages(GFP_NOFS, 0);
  59         if (unlikely(!buf))
  60                 return -ENOMEM;
  61         maxmembs = PAGE_SIZE / argv->v_size;
  62
  63         ret = 0;
  64         total = 0;
  65         pos = argv->v_index;
  66         for (i = 0; i < argv->v_nmembs; i += n) {
  67                 n = (argv->v_nmembs - i < maxmembs) ?
  68                         argv->v_nmembs - i : maxmembs;
  69                 if ((dir & _IOC_WRITE) &&
  70                     copy_from_user(buf, base + argv->v_size * i,
  71                                    argv->v_size * n)) {
  72                         ret = -EFAULT;
  73                         break;
  74                 }
  75                 ppos = pos;
  76                 nr = dofunc(nilfs, &pos, argv->v_flags, buf, argv->v_size,
  77                                n);
  78                 if (nr < 0) {
  79                         ret = nr;
  80                         break;
  81                 }
  82                 if ((dir & _IOC_READ) &&
  83                     copy_to_user(base + argv->v_size * i, buf,
  84                                  argv->v_size * nr)) {
  85                         ret = -EFAULT;
  86                         break;
  87                 }
  88                 total += nr;
  89                 if ((size_t)nr < n)
  90                         break;
  91                 if (pos == ppos)
  92                         pos += n;
  93         }
  94         argv->v_nmembs = total;
  95
  96         free_pages((unsigned long)buf, 0);
  97         return ret;
  98 }
  99
 100 static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
 101                                      unsigned int cmd, void __user *argp)
 102 {
 103         struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
 104         struct inode *cpfile = nilfs->ns_cpfile;
 105         struct nilfs_transaction_info ti;
 106         struct nilfs_cpmode cpmode;
 107         int ret;
 108
 109         if (!capable(CAP_SYS_ADMIN))
 110                 return -EPERM;
 111
 112         ret = mnt_want_write(filp->f_path.mnt);
 113         if (ret)
 114                 return ret;
 115
 116         ret = -EFAULT;
 117         if (copy_from_user(&cpmode, argp, sizeof(cpmode)))
 118                 goto out;
 119
 120         down_read(&inode->i_sb->s_umount);
 121
 122         nilfs_transaction_begin(inode->i_sb, &ti, 0);
 123         ret = nilfs_cpfile_change_cpmode(
 124                 cpfile, cpmode.cm_cno, cpmode.cm_mode);
 125         if (unlikely(ret < 0))
 126                 nilfs_transaction_abort(inode->i_sb);
 127         else
 128                 nilfs_transaction_commit(inode->i_sb); /* never fails */
 129
 130         up_read(&inode->i_sb->s_umount);
 131 out:
 132         mnt_drop_write(filp->f_path.mnt);
 133         return ret;
 134 }
 135
 136 static int
 137 nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
 138                               unsigned int cmd, void __user *argp)
 139 {
 140         struct inode *cpfile = NILFS_SB(inode->i_sb)->s_nilfs->ns_cpfile;
 141         struct nilfs_transaction_info ti;
 142         __u64 cno;
 143         int ret;
 144
 145         if (!capable(CAP_SYS_ADMIN))
 146                 return -EPERM;
 147
 148         ret = mnt_want_write(filp->f_path.mnt);
 149         if (ret)
 150                 return ret;
 151
 152         ret = -EFAULT;
 153         if (copy_from_user(&cno, argp, sizeof(cno)))
 154                 goto out;
 155
 156         nilfs_transaction_begin(inode->i_sb, &ti, 0);
 157         ret = nilfs_cpfile_delete_checkpoint(cpfile, cno);
 158         if (unlikely(ret < 0))
 159                 nilfs_transaction_abort(inode->i_sb);
 160         else
 161                 nilfs_transaction_commit(inode->i_sb); /* never fails */
 162 out:
 163         mnt_drop_write(filp->f_path.mnt);
 164         return ret;
 165 }
 166
 167 static ssize_t
 168 nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 169                           void *buf, size_t size, size_t nmembs)
 170 {
 171         int ret;
 172
 173         down_read(&nilfs->ns_segctor_sem);
 174         ret = nilfs_cpfile_get_cpinfo(nilfs->ns_cpfile, posp, flags, buf,
 175                                       size, nmembs);
 176         up_read(&nilfs->ns_segctor_sem);
 177         return ret;
 178 }
 179
 180 static int nilfs_ioctl_get_cpstat(struct inode *inode, struct file *filp,
 181                                   unsigned int cmd, void __user *argp)
 182 {
 183         struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
 184         struct nilfs_cpstat cpstat;
 185         int ret;
 186
 187         down_read(&nilfs->ns_segctor_sem);
 188         ret = nilfs_cpfile_get_stat(nilfs->ns_cpfile, &cpstat);
 189         up_read(&nilfs->ns_segctor_sem);
 190         if (ret < 0)
 191                 return ret;
 192
 193         if (copy_to_user(argp, &cpstat, sizeof(cpstat)))
 194                 ret = -EFAULT;
 195         return ret;
 196 }
 197
 198 static ssize_t
 199 nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 200                           void *buf, size_t size, size_t nmembs)
 201 {
 202         int ret;
 203
 204         down_read(&nilfs->ns_segctor_sem);
 205         ret = nilfs_sufile_get_suinfo(nilfs->ns_sufile, *posp, buf, size,
 206                                       nmembs);
 207         up_read(&nilfs->ns_segctor_sem);
 208         return ret;
 209 }
 210
 211 static int nilfs_ioctl_get_sustat(struct inode *inode, struct file *filp,
 212                                   unsigned int cmd, void __user *argp)
 213 {
 214         struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
 215         struct nilfs_sustat sustat;
 216         int ret;
 217
 218         down_read(&nilfs->ns_segctor_sem);
 219         ret = nilfs_sufile_get_stat(nilfs->ns_sufile, &sustat);
 220         up_read(&nilfs->ns_segctor_sem);
 221         if (ret < 0)
 222                 return ret;
 223
 224         if (copy_to_user(argp, &sustat, sizeof(sustat)))
 225                 ret = -EFAULT;
 226         return ret;
 227 }
 228
 229 static ssize_t
 230 nilfs_ioctl_do_get_vinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 231                          void *buf, size_t size, size_t nmembs)
 232 {
 233         int ret;
 234
 235         down_read(&nilfs->ns_segctor_sem);
 236         ret = nilfs_dat_get_vinfo(nilfs->ns_dat, buf, size, nmembs);
 237         up_read(&nilfs->ns_segctor_sem);
 238         return ret;
 239 }
 240
 241 static ssize_t
 242 nilfs_ioctl_do_get_bdescs(struct the_nilfs *nilfs, __u64 *posp, int flags,
 243                           void *buf, size_t size, size_t nmembs)
 244 {
 245         struct nilfs_bmap *bmap = NILFS_I(nilfs->ns_dat)->i_bmap;
 246         struct nilfs_bdesc *bdescs = buf;
 247         int ret, i;
 248
 249         down_read(&nilfs->ns_segctor_sem);
 250         for (i = 0; i < nmembs; i++) {
 251                 ret = nilfs_bmap_lookup_at_level(bmap,
 252                                                  bdescs[i].bd_offset,
 253                                                  bdescs[i].bd_level + 1,
 254                                                  &bdescs[i].bd_blocknr);
 255                 if (ret < 0) {
 256                         if (ret != -ENOENT) {
 257                                 up_read(&nilfs->ns_segctor_sem);
 258                                 return ret;
 259                         }
 260                         bdescs[i].bd_blocknr = 0;
 261                 }
 262         }
 263         up_read(&nilfs->ns_segctor_sem);
 264         return nmembs;
 265 }
 266
 267 static int nilfs_ioctl_get_bdescs(struct inode *inode, struct file *filp,
 268                                   unsigned int cmd, void __user *argp)
 269 {
 270         struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
 271         struct nilfs_argv argv;
 272         int ret;
 273
 274         if (copy_from_user(&argv, argp, sizeof(argv)))
 275                 return -EFAULT;
 276
 277         if (argv.v_size != sizeof(struct nilfs_bdesc))
 278                 return -EINVAL;
 279
 280         ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
 281                                     nilfs_ioctl_do_get_bdescs);
 282         if (ret < 0)
 283                 return ret;
 284
 285         if (copy_to_user(argp, &argv, sizeof(argv)))
 286                 ret = -EFAULT;
 287         return ret;
 288 }
 289
 290 static int nilfs_ioctl_move_inode_block(struct inode *inode,
 291                                         struct nilfs_vdesc *vdesc,
 292                                         struct list_head *buffers)
 293 {
 294         struct buffer_head *bh;
 295         int ret;
 296
 297         if (vdesc->vd_flags == 0)
 298                 ret = nilfs_gccache_submit_read_data(
 299                         inode, vdesc->vd_offset, vdesc->vd_blocknr,
 300                         vdesc->vd_vblocknr, &bh);
 301         else
 302                 ret = nilfs_gccache_submit_read_node(
 303                         inode, vdesc->vd_blocknr, vdesc->vd_vblocknr, &bh);
 304
 305         if (unlikely(ret < 0)) {
 306                 if (ret == -ENOENT)
 307                         printk(KERN_CRIT
 308                                "%s: invalid virtual block address (%s): "
 309                                "ino=%llu, cno=%llu, offset=%llu, "
 310                                "blocknr=%llu, vblocknr=%llu\n",
 311                                __func__, vdesc->vd_flags ? "node" : "data",
 312                                (unsigned long long)vdesc->vd_ino,
 313                                (unsigned long long)vdesc->vd_cno,
 314                                (unsigned long long)vdesc->vd_offset,
 315                                (unsigned long long)vdesc->vd_blocknr,
 316                                (unsigned long long)vdesc->vd_vblocknr);
 317                 return ret;
 318         }
 319         if (unlikely(!list_empty(&bh->b_assoc_buffers))) {
 320                 printk(KERN_CRIT "%s: conflicting %s buffer: ino=%llu, "
 321                        "cno=%llu, offset=%llu, blocknr=%llu, vblocknr=%llu\n",
 322                        __func__, vdesc->vd_flags ? "node" : "data",
 323                        (unsigned long long)vdesc->vd_ino,
 324                        (unsigned long long)vdesc->vd_cno,
 325                        (unsigned long long)vdesc->vd_offset,
 326                        (unsigned long long)vdesc->vd_blocknr,
 327                        (unsigned long long)vdesc->vd_vblocknr);
 328                 brelse(bh);
 329                 return -EEXIST;
 330         }
 331         list_add_tail(&bh->b_assoc_buffers, buffers);
 332         return 0;
 333 }
 334
 335 static int nilfs_ioctl_move_blocks(struct super_block *sb,
 336                                    struct nilfs_argv *argv, void *buf)
 337 {
 338         size_t nmembs = argv->v_nmembs;
 339         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 340         struct inode *inode;
 341         struct nilfs_vdesc *vdesc;
 342         struct buffer_head *bh, *n;
 343         LIST_HEAD(buffers);
 344         ino_t ino;
 345         __u64 cno;
 346         int i, ret;
 347
 348         for (i = 0, vdesc = buf; i < nmembs; ) {
 349                 ino = vdesc->vd_ino;
 350                 cno = vdesc->vd_cno;
 351                 inode = nilfs_iget_for_gc(sb, ino, cno);
 352                 if (IS_ERR(inode)) {
 353                         ret = PTR_ERR(inode);
 354                         goto failed;
 355                 }
 356                 if (list_empty(&NILFS_I(inode)->i_dirty)) {
 357                         /*
 358                          * Add the inode to GC inode list. Garbage Collection
 359                          * is serialized and no two processes manipulate the
 360                          * list simultaneously.
 361                          */
 362                         igrab(inode);
 363                         list_add(&NILFS_I(inode)->i_dirty,
 364                                  &nilfs->ns_gc_inodes);
 365                 }
 366
 367                 do {
 368                         ret = nilfs_ioctl_move_inode_block(inode, vdesc,
 369                                                            &buffers);
 370                         if (unlikely(ret < 0)) {
 371                                 iput(inode);
 372                                 goto failed;
 373                         }
 374                         vdesc++;
 375                 } while (++i < nmembs &&
 376                          vdesc->vd_ino == ino && vdesc->vd_cno == cno);
 377
 378                 iput(inode); /* The inode still remains in GC inode list */
 379         }
 380
 381         list_for_each_entry_safe(bh, n, &buffers, b_assoc_buffers) {
 382                 ret = nilfs_gccache_wait_and_mark_dirty(bh);
 383                 if (unlikely(ret < 0)) {
 384                         WARN_ON(ret == -EEXIST);
 385                         goto failed;
 386                 }
 387                 list_del_init(&bh->b_assoc_buffers);
 388                 brelse(bh);
 389         }
 390         return nmembs;
 391
 392  failed:
 393         list_for_each_entry_safe(bh, n, &buffers, b_assoc_buffers) {
 394                 list_del_init(&bh->b_assoc_buffers);
 395                 brelse(bh);
 396         }
 397         return ret;
 398 }
 399
 400 static int nilfs_ioctl_delete_checkpoints(struct the_nilfs *nilfs,
 401                                           struct nilfs_argv *argv, void *buf)
 402 {
 403         size_t nmembs = argv->v_nmembs;
 404         struct inode *cpfile = nilfs->ns_cpfile;
 405         struct nilfs_period *periods = buf;
 406         int ret, i;
 407
 408         for (i = 0; i < nmembs; i++) {
 409                 ret = nilfs_cpfile_delete_checkpoints(
 410                         cpfile, periods[i].p_start, periods[i].p_end);
 411                 if (ret < 0)
 412                         return ret;
 413         }
 414         return nmembs;
 415 }
 416
 417 static int nilfs_ioctl_free_vblocknrs(struct the_nilfs *nilfs,
 418                                       struct nilfs_argv *argv, void *buf)
 419 {
 420         size_t nmembs = argv->v_nmembs;
 421         int ret;
 422
 423         ret = nilfs_dat_freev(nilfs->ns_dat, buf, nmembs);
 424
 425         return (ret < 0) ? ret : nmembs;
 426 }
 427
 428 static int nilfs_ioctl_mark_blocks_dirty(struct the_nilfs *nilfs,
 429                                          struct nilfs_argv *argv, void *buf)
 430 {
 431         size_t nmembs = argv->v_nmembs;
 432         struct nilfs_bmap *bmap = NILFS_I(nilfs->ns_dat)->i_bmap;
 433         struct nilfs_bdesc *bdescs = buf;
 434         int ret, i;
 435
 436         for (i = 0; i < nmembs; i++) {
 437                 /* XXX: use macro or inline func to check liveness */
 438                 ret = nilfs_bmap_lookup_at_level(bmap,
 439                                                  bdescs[i].bd_offset,
 440                                                  bdescs[i].bd_level + 1,
 441                                                  &bdescs[i].bd_blocknr);
 442                 if (ret < 0) {
 443                         if (ret != -ENOENT)
 444                                 return ret;
 445                         bdescs[i].bd_blocknr = 0;
 446                 }
 447                 if (bdescs[i].bd_blocknr != bdescs[i].bd_oblocknr)
 448                         /* skip dead block */
 449                         continue;
 450                 if (bdescs[i].bd_level == 0) {
 451                         ret = nilfs_mdt_mark_block_dirty(nilfs->ns_dat,
 452                                                          bdescs[i].bd_offset);
 453                         if (ret < 0) {
 454                                 WARN_ON(ret == -ENOENT);
 455                                 return ret;
 456                         }
 457                 } else {
 458                         ret = nilfs_bmap_mark(bmap, bdescs[i].bd_offset,
 459                                               bdescs[i].bd_level);
 460                         if (ret < 0) {
 461                                 WARN_ON(ret == -ENOENT);
 462                                 return ret;
 463                         }
 464                 }
 465         }
 466         return nmembs;
 467 }
 468
 469 int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,
 470                                        struct nilfs_argv *argv, void **kbufs)
 471 {
 472         const char *msg;
 473         int ret;
 474
 475         ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], kbufs[1]);
 476         if (ret < 0) {
 477                 /*
 478                  * can safely abort because checkpoints can be removed
 479                  * independently.
 480                  */
 481                 msg = "cannot delete checkpoints";
 482                 goto failed;
 483         }
 484         ret = nilfs_ioctl_free_vblocknrs(nilfs, &argv[2], kbufs[2]);
 485         if (ret < 0) {
 486                 /*
 487                  * can safely abort because DAT file is updated atomically
 488                  * using a copy-on-write technique.
 489                  */
 490                 msg = "cannot delete virtual blocks from DAT file";
 491                 goto failed;
 492         }
 493         ret = nilfs_ioctl_mark_blocks_dirty(nilfs, &argv[3], kbufs[3]);
 494         if (ret < 0) {
 495                 /*
 496                  * can safely abort because the operation is nondestructive.
 497                  */
 498                 msg = "cannot mark copying blocks dirty";
 499                 goto failed;
 500         }
 501         return 0;
 502
 503  failed:
 504         printk(KERN_ERR "NILFS: GC failed during preparation: %s: err=%d\n",
 505                msg, ret);
 506         return ret;
 507 }
 508
 509 static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 510                                       unsigned int cmd, void __user *argp)
 511 {
 512         struct nilfs_argv argv[5];
 513         static const size_t argsz[5] = {
 514                 sizeof(struct nilfs_vdesc),
 515                 sizeof(struct nilfs_period),
 516                 sizeof(__u64),
 517                 sizeof(struct nilfs_bdesc),
 518                 sizeof(__u64),
 519         };
 520         void __user *base;
 521         void *kbufs[5];
 522         struct the_nilfs *nilfs;
 523         size_t len, nsegs;
 524         int n, ret;
 525
 526         if (!capable(CAP_SYS_ADMIN))
 527                 return -EPERM;
 528
 529         ret = mnt_want_write(filp->f_path.mnt);
 530         if (ret)
 531                 return ret;
 532
 533         ret = -EFAULT;
 534         if (copy_from_user(argv, argp, sizeof(argv)))
 535                 goto out;
 536
 537         ret = -EINVAL;
 538         nsegs = argv[4].v_nmembs;
 539         if (argv[4].v_size != argsz[4])
 540                 goto out;
 541
 542         /*
 543          * argv[4] points to segment numbers this ioctl cleans.  We
 544          * use kmalloc() for its buffer because memory used for the
 545          * segment numbers is enough small.
 546          */
 547         kbufs[4] = memdup_user((void __user *)(unsigned long)argv[4].v_base,
 548                                nsegs * sizeof(__u64));
 549         if (IS_ERR(kbufs[4])) {
 550                 ret = PTR_ERR(kbufs[4]);
 551                 goto out;
 552         }
 553         nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
 554
 555         for (n = 0; n < 4; n++) {
 556                 ret = -EINVAL;
 557                 if (argv[n].v_size != argsz[n])
 558                         goto out_free;
 559
 560                 if (argv[n].v_nmembs > nsegs * nilfs->ns_blocks_per_segment)
 561                         goto out_free;
 562
 563                 len = argv[n].v_size * argv[n].v_nmembs;
 564                 base = (void __user *)(unsigned long)argv[n].v_base;
 565                 if (len == 0) {
 566                         kbufs[n] = NULL;
 567                         continue;
 568                 }
 569
 570                 kbufs[n] = vmalloc(len);
 571                 if (!kbufs[n]) {
 572                         ret = -ENOMEM;
 573                         goto out_free;
 574                 }
 575                 if (copy_from_user(kbufs[n], base, len)) {
 576                         ret = -EFAULT;
 577                         vfree(kbufs[n]);
 578                         goto out_free;
 579                 }
 580         }
 581
 582         /*
 583          * nilfs_ioctl_move_blocks() will call nilfs_iget_for_gc(),
 584          * which will operates an inode list without blocking.
 585          * To protect the list from concurrent operations,
 586          * nilfs_ioctl_move_blocks should be atomic operation.
 587          */
 588         if (test_and_set_bit(THE_NILFS_GC_RUNNING, &nilfs->ns_flags)) {
 589                 ret = -EBUSY;
 590                 goto out_free;
 591         }
 592
 593         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 594
 595         ret = nilfs_ioctl_move_blocks(inode->i_sb, &argv[0], kbufs[0]);
 596         if (ret < 0)
 597                 printk(KERN_ERR "NILFS: GC failed during preparation: "
 598                         "cannot read source blocks: err=%d\n", ret);
 599         else
 600                 ret = nilfs_clean_segments(inode->i_sb, argv, kbufs);
 601
 602         nilfs_remove_all_gcinodes(nilfs);
 603         clear_nilfs_gc_running(nilfs);
 604
 605 out_free:
 606         while (--n >= 0)
 607                 vfree(kbufs[n]);
 608         kfree(kbufs[4]);
 609 out:
 610         mnt_drop_write(filp->f_path.mnt);
 611         return ret;
 612 }
 613
 614 static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
 615                             unsigned int cmd, void __user *argp)
 616 {
 617         __u64 cno;
 618         int ret;
 619         struct the_nilfs *nilfs;
 620
 621         ret = nilfs_construct_segment(inode->i_sb);
 622         if (ret < 0)
 623                 return ret;
 624
 625         if (argp != NULL) {
 626                 nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
 627                 down_read(&nilfs->ns_segctor_sem);
 628                 cno = nilfs->ns_cno - 1;
 629                 up_read(&nilfs->ns_segctor_sem);
 630                 if (copy_to_user(argp, &cno, sizeof(cno)))
 631                         return -EFAULT;
 632         }
 633         return 0;
 634 }
 635
 636 static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp,
 637                                 unsigned int cmd, void __user *argp,
 638                                 size_t membsz,
 639                                 ssize_t (*dofunc)(struct the_nilfs *,
 640                                                   __u64 *, int,
 641                                                   void *, size_t, size_t))
 642
 643 {
 644         struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
 645         struct nilfs_argv argv;
 646         int ret;
 647
 648         if (copy_from_user(&argv, argp, sizeof(argv)))
 649                 return -EFAULT;
 650
 651         if (argv.v_size < membsz)
 652                 return -EINVAL;
 653
 654         ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), dofunc);
 655         if (ret < 0)
 656                 return ret;
 657
 658         if (copy_to_user(argp, &argv, sizeof(argv)))
 659                 ret = -EFAULT;
 660         return ret;
 661 }
 662
 663 long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 664 {
 665         struct inode *inode = filp->f_dentry->d_inode;
 666         void __user *argp = (void __user *)arg;
 667
 668         switch (cmd) {
 669         case NILFS_IOCTL_CHANGE_CPMODE:
 670                 return nilfs_ioctl_change_cpmode(inode, filp, cmd, argp);
 671         case NILFS_IOCTL_DELETE_CHECKPOINT:
 672                 return nilfs_ioctl_delete_checkpoint(inode, filp, cmd, argp);
 673         case NILFS_IOCTL_GET_CPINFO:
 674                 return nilfs_ioctl_get_info(inode, filp, cmd, argp,
 675                                             sizeof(struct nilfs_cpinfo),
 676                                             nilfs_ioctl_do_get_cpinfo);
 677         case NILFS_IOCTL_GET_CPSTAT:
 678                 return nilfs_ioctl_get_cpstat(inode, filp, cmd, argp);
 679         case NILFS_IOCTL_GET_SUINFO:
 680                 return nilfs_ioctl_get_info(inode, filp, cmd, argp,
 681                                             sizeof(struct nilfs_suinfo),
 682                                             nilfs_ioctl_do_get_suinfo);
 683         case NILFS_IOCTL_GET_SUSTAT:
 684                 return nilfs_ioctl_get_sustat(inode, filp, cmd, argp);
 685         case NILFS_IOCTL_GET_VINFO:
 686                 return nilfs_ioctl_get_info(inode, filp, cmd, argp,
 687                                             sizeof(struct nilfs_vinfo),
 688                                             nilfs_ioctl_do_get_vinfo);
 689         case NILFS_IOCTL_GET_BDESCS:
 690                 return nilfs_ioctl_get_bdescs(inode, filp, cmd, argp);
 691         case NILFS_IOCTL_CLEAN_SEGMENTS:
 692                 return nilfs_ioctl_clean_segments(inode, filp, cmd, argp);
 693         case NILFS_IOCTL_SYNC:
 694                 return nilfs_ioctl_sync(inode, filp, cmd, argp);
 695         default:
 696                 return -ENOTTY;
 697         }
 698 }