git.oblomov.eu Git - linux-2.6/blob - fs/btrfs/ioctl.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/fsnotify.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/highmem.h>
  27 #include <linux/time.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/backing-dev.h>
  32 #include <linux/mount.h>
  33 #include <linux/mpage.h>
  34 #include <linux/namei.h>
  35 #include <linux/swap.h>
  36 #include <linux/writeback.h>
  37 #include <linux/statfs.h>
  38 #include <linux/compat.h>
  39 #include <linux/bit_spinlock.h>
  40 #include <linux/security.h>
  41 #include <linux/xattr.h>
  42 #include <linux/vmalloc.h>
  43 #include "compat.h"
  44 #include "ctree.h"
  45 #include "disk-io.h"
  46 #include "transaction.h"
  47 #include "btrfs_inode.h"
  48 #include "ioctl.h"
  49 #include "print-tree.h"
  50 #include "volumes.h"
  51 #include "locking.h"
  52
  53 /* Mask out flags that are inappropriate for the given type of inode. */
  54 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
  55 {
  56         if (S_ISDIR(mode))
  57                 return flags;
  58         else if (S_ISREG(mode))
  59                 return flags & ~FS_DIRSYNC_FL;
  60         else
  61                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
  62 }
  63
  64 /*
  65  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
  66  */
  67 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
  68 {
  69         unsigned int iflags = 0;
  70
  71         if (flags & BTRFS_INODE_SYNC)
  72                 iflags |= FS_SYNC_FL;
  73         if (flags & BTRFS_INODE_IMMUTABLE)
  74                 iflags |= FS_IMMUTABLE_FL;
  75         if (flags & BTRFS_INODE_APPEND)
  76                 iflags |= FS_APPEND_FL;
  77         if (flags & BTRFS_INODE_NODUMP)
  78                 iflags |= FS_NODUMP_FL;
  79         if (flags & BTRFS_INODE_NOATIME)
  80                 iflags |= FS_NOATIME_FL;
  81         if (flags & BTRFS_INODE_DIRSYNC)
  82                 iflags |= FS_DIRSYNC_FL;
  83
  84         return iflags;
  85 }
  86
  87 /*
  88  * Update inode->i_flags based on the btrfs internal flags.
  89  */
  90 void btrfs_update_iflags(struct inode *inode)
  91 {
  92         struct btrfs_inode *ip = BTRFS_I(inode);
  93
  94         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
  95
  96         if (ip->flags & BTRFS_INODE_SYNC)
  97                 inode->i_flags |= S_SYNC;
  98         if (ip->flags & BTRFS_INODE_IMMUTABLE)
  99                 inode->i_flags |= S_IMMUTABLE;
 100         if (ip->flags & BTRFS_INODE_APPEND)
 101                 inode->i_flags |= S_APPEND;
 102         if (ip->flags & BTRFS_INODE_NOATIME)
 103                 inode->i_flags |= S_NOATIME;
 104         if (ip->flags & BTRFS_INODE_DIRSYNC)
 105                 inode->i_flags |= S_DIRSYNC;
 106 }
 107
 108 /*
 109  * Inherit flags from the parent inode.
 110  *
 111  * Unlike extN we don't have any flags we don't want to inherit currently.
 112  */
 113 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
 114 {
 115         unsigned int flags;
 116
 117         if (!dir)
 118                 return;
 119
 120         flags = BTRFS_I(dir)->flags;
 121
 122         if (S_ISREG(inode->i_mode))
 123                 flags &= ~BTRFS_INODE_DIRSYNC;
 124         else if (!S_ISDIR(inode->i_mode))
 125                 flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);
 126
 127         BTRFS_I(inode)->flags = flags;
 128         btrfs_update_iflags(inode);
 129 }
 130
 131 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
 132 {
 133         struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
 134         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
 135
 136         if (copy_to_user(arg, &flags, sizeof(flags)))
 137                 return -EFAULT;
 138         return 0;
 139 }
 140
 141 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 142 {
 143         struct inode *inode = file->f_path.dentry->d_inode;
 144         struct btrfs_inode *ip = BTRFS_I(inode);
 145         struct btrfs_root *root = ip->root;
 146         struct btrfs_trans_handle *trans;
 147         unsigned int flags, oldflags;
 148         int ret;
 149
 150         if (copy_from_user(&flags, arg, sizeof(flags)))
 151                 return -EFAULT;
 152
 153         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
 154                       FS_NOATIME_FL | FS_NODUMP_FL | \
 155                       FS_SYNC_FL | FS_DIRSYNC_FL))
 156                 return -EOPNOTSUPP;
 157
 158         if (!is_owner_or_cap(inode))
 159                 return -EACCES;
 160
 161         mutex_lock(&inode->i_mutex);
 162
 163         flags = btrfs_mask_flags(inode->i_mode, flags);
 164         oldflags = btrfs_flags_to_ioctl(ip->flags);
 165         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
 166                 if (!capable(CAP_LINUX_IMMUTABLE)) {
 167                         ret = -EPERM;
 168                         goto out_unlock;
 169                 }
 170         }
 171
 172         ret = mnt_want_write(file->f_path.mnt);
 173         if (ret)
 174                 goto out_unlock;
 175
 176         if (flags & FS_SYNC_FL)
 177                 ip->flags |= BTRFS_INODE_SYNC;
 178         else
 179                 ip->flags &= ~BTRFS_INODE_SYNC;
 180         if (flags & FS_IMMUTABLE_FL)
 181                 ip->flags |= BTRFS_INODE_IMMUTABLE;
 182         else
 183                 ip->flags &= ~BTRFS_INODE_IMMUTABLE;
 184         if (flags & FS_APPEND_FL)
 185                 ip->flags |= BTRFS_INODE_APPEND;
 186         else
 187                 ip->flags &= ~BTRFS_INODE_APPEND;
 188         if (flags & FS_NODUMP_FL)
 189                 ip->flags |= BTRFS_INODE_NODUMP;
 190         else
 191                 ip->flags &= ~BTRFS_INODE_NODUMP;
 192         if (flags & FS_NOATIME_FL)
 193                 ip->flags |= BTRFS_INODE_NOATIME;
 194         else
 195                 ip->flags &= ~BTRFS_INODE_NOATIME;
 196         if (flags & FS_DIRSYNC_FL)
 197                 ip->flags |= BTRFS_INODE_DIRSYNC;
 198         else
 199                 ip->flags &= ~BTRFS_INODE_DIRSYNC;
 200
 201
 202         trans = btrfs_join_transaction(root, 1);
 203         BUG_ON(!trans);
 204
 205         ret = btrfs_update_inode(trans, root, inode);
 206         BUG_ON(ret);
 207
 208         btrfs_update_iflags(inode);
 209         inode->i_ctime = CURRENT_TIME;
 210         btrfs_end_transaction(trans, root);
 211
 212         mnt_drop_write(file->f_path.mnt);
 213  out_unlock:
 214         mutex_unlock(&inode->i_mutex);
 215         return 0;
 216 }
 217
 218 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 219 {
 220         struct inode *inode = file->f_path.dentry->d_inode;
 221
 222         return put_user(inode->i_generation, arg);
 223 }
 224
 225 static noinline int create_subvol(struct btrfs_root *root,
 226                                   struct dentry *dentry,
 227                                   char *name, int namelen)
 228 {
 229         struct btrfs_trans_handle *trans;
 230         struct btrfs_key key;
 231         struct btrfs_root_item root_item;
 232         struct btrfs_inode_item *inode_item;
 233         struct extent_buffer *leaf;
 234         struct btrfs_root *new_root = root;
 235         struct inode *dir;
 236         int ret;
 237         int err;
 238         u64 objectid;
 239         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
 240         u64 index = 0;
 241         unsigned long nr = 1;
 242
 243         ret = btrfs_check_metadata_free_space(root);
 244         if (ret)
 245                 goto fail_commit;
 246
 247         trans = btrfs_start_transaction(root, 1);
 248         BUG_ON(!trans);
 249
 250         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
 251                                        0, &objectid);
 252         if (ret)
 253                 goto fail;
 254
 255         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
 256                                       0, objectid, NULL, 0, 0, 0);
 257         if (IS_ERR(leaf)) {
 258                 ret = PTR_ERR(leaf);
 259                 goto fail;
 260         }
 261
 262         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
 263         btrfs_set_header_bytenr(leaf, leaf->start);
 264         btrfs_set_header_generation(leaf, trans->transid);
 265         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
 266         btrfs_set_header_owner(leaf, objectid);
 267
 268         write_extent_buffer(leaf, root->fs_info->fsid,
 269                             (unsigned long)btrfs_header_fsid(leaf),
 270                             BTRFS_FSID_SIZE);
 271         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 272                             (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
 273                             BTRFS_UUID_SIZE);
 274         btrfs_mark_buffer_dirty(leaf);
 275
 276         inode_item = &root_item.inode;
 277         memset(inode_item, 0, sizeof(*inode_item));
 278         inode_item->generation = cpu_to_le64(1);
 279         inode_item->size = cpu_to_le64(3);
 280         inode_item->nlink = cpu_to_le32(1);
 281         inode_item->nbytes = cpu_to_le64(root->leafsize);
 282         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 283
 284         btrfs_set_root_bytenr(&root_item, leaf->start);
 285         btrfs_set_root_generation(&root_item, trans->transid);
 286         btrfs_set_root_level(&root_item, 0);
 287         btrfs_set_root_refs(&root_item, 1);
 288         btrfs_set_root_used(&root_item, 0);
 289         btrfs_set_root_last_snapshot(&root_item, 0);
 290
 291         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 292         root_item.drop_level = 0;
 293
 294         btrfs_tree_unlock(leaf);
 295         free_extent_buffer(leaf);
 296         leaf = NULL;
 297
 298         btrfs_set_root_dirid(&root_item, new_dirid);
 299
 300         key.objectid = objectid;
 301         key.offset = 0;
 302         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 303         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 304                                 &root_item);
 305         if (ret)
 306                 goto fail;
 307
 308         /*
 309          * insert the directory item
 310          */
 311         key.offset = (u64)-1;
 312         dir = dentry->d_parent->d_inode;
 313         ret = btrfs_set_inode_index(dir, &index);
 314         BUG_ON(ret);
 315
 316         ret = btrfs_insert_dir_item(trans, root,
 317                                     name, namelen, dir->i_ino, &key,
 318                                     BTRFS_FT_DIR, index);
 319         if (ret)
 320                 goto fail;
 321
 322         btrfs_i_size_write(dir, dir->i_size + namelen * 2);
 323         ret = btrfs_update_inode(trans, root, dir);
 324         BUG_ON(ret);
 325
 326         /* add the backref first */
 327         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
 328                                  objectid, BTRFS_ROOT_BACKREF_KEY,
 329                                  root->root_key.objectid,
 330                                  dir->i_ino, index, name, namelen);
 331
 332         BUG_ON(ret);
 333
 334         /* now add the forward ref */
 335         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
 336                                  root->root_key.objectid, BTRFS_ROOT_REF_KEY,
 337                                  objectid,
 338                                  dir->i_ino, index, name, namelen);
 339
 340         BUG_ON(ret);
 341
 342         ret = btrfs_commit_transaction(trans, root);
 343         if (ret)
 344                 goto fail_commit;
 345
 346         new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
 347         BUG_ON(!new_root);
 348
 349         trans = btrfs_start_transaction(new_root, 1);
 350         BUG_ON(!trans);
 351
 352         ret = btrfs_create_subvol_root(trans, new_root, dentry, new_dirid,
 353                                        BTRFS_I(dir)->block_group);
 354         if (ret)
 355                 goto fail;
 356
 357 fail:
 358         nr = trans->blocks_used;
 359         err = btrfs_commit_transaction(trans, new_root);
 360         if (err && !ret)
 361                 ret = err;
 362 fail_commit:
 363         btrfs_btree_balance_dirty(root, nr);
 364         return ret;
 365 }
 366
 367 static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 368                            char *name, int namelen)
 369 {
 370         struct btrfs_pending_snapshot *pending_snapshot;
 371         struct btrfs_trans_handle *trans;
 372         int ret = 0;
 373         int err;
 374         unsigned long nr = 0;
 375
 376         if (!root->ref_cows)
 377                 return -EINVAL;
 378
 379         ret = btrfs_check_metadata_free_space(root);
 380         if (ret)
 381                 goto fail_unlock;
 382
 383         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
 384         if (!pending_snapshot) {
 385                 ret = -ENOMEM;
 386                 goto fail_unlock;
 387         }
 388         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 389         if (!pending_snapshot->name) {
 390                 ret = -ENOMEM;
 391                 kfree(pending_snapshot);
 392                 goto fail_unlock;
 393         }
 394         memcpy(pending_snapshot->name, name, namelen);
 395         pending_snapshot->name[namelen] = '\0';
 396         pending_snapshot->dentry = dentry;
 397         trans = btrfs_start_transaction(root, 1);
 398         BUG_ON(!trans);
 399         pending_snapshot->root = root;
 400         list_add(&pending_snapshot->list,
 401                  &trans->transaction->pending_snapshots);
 402         err = btrfs_commit_transaction(trans, root);
 403
 404 fail_unlock:
 405         btrfs_btree_balance_dirty(root, nr);
 406         return ret;
 407 }
 408
 409 /* copy of may_create in fs/namei.c() */
 410 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 411 {
 412         if (child->d_inode)
 413                 return -EEXIST;
 414         if (IS_DEADDIR(dir))
 415                 return -ENOENT;
 416         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 417 }
 418
 419 /*
 420  * Create a new subvolume below @parent.  This is largely modeled after
 421  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 422  * inside this filesystem so it's quite a bit simpler.
 423  */
 424 static noinline int btrfs_mksubvol(struct path *parent, char *name,
 425                                    int mode, int namelen,
 426                                    struct btrfs_root *snap_src)
 427 {
 428         struct dentry *dentry;
 429         int error;
 430
 431         mutex_lock_nested(&parent->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 432
 433         dentry = lookup_one_len(name, parent->dentry, namelen);
 434         error = PTR_ERR(dentry);
 435         if (IS_ERR(dentry))
 436                 goto out_unlock;
 437
 438         error = -EEXIST;
 439         if (dentry->d_inode)
 440                 goto out_dput;
 441
 442         if (!IS_POSIXACL(parent->dentry->d_inode))
 443                 mode &= ~current_umask();
 444
 445         error = mnt_want_write(parent->mnt);
 446         if (error)
 447                 goto out_dput;
 448
 449         error = btrfs_may_create(parent->dentry->d_inode, dentry);
 450         if (error)
 451                 goto out_drop_write;
 452
 453         /*
 454          * Actually perform the low-level subvolume creation after all
 455          * this VFS fuzz.
 456          *
 457          * Eventually we want to pass in an inode under which we create this
 458          * subvolume, but for now all are under the filesystem root.
 459          *
 460          * Also we should pass on the mode eventually to allow creating new
 461          * subvolume with specific mode bits.
 462          */
 463         if (snap_src) {
 464                 struct dentry *dir = dentry->d_parent;
 465                 struct dentry *test = dir->d_parent;
 466                 struct btrfs_path *path = btrfs_alloc_path();
 467                 int ret;
 468                 u64 test_oid;
 469                 u64 parent_oid = BTRFS_I(dir->d_inode)->root->root_key.objectid;
 470
 471                 test_oid = snap_src->root_key.objectid;
 472
 473                 ret = btrfs_find_root_ref(snap_src->fs_info->tree_root,
 474                                           path, parent_oid, test_oid);
 475                 if (ret == 0)
 476                         goto create;
 477                 btrfs_release_path(snap_src->fs_info->tree_root, path);
 478
 479                 /* we need to make sure we aren't creating a directory loop
 480                  * by taking a snapshot of something that has our current
 481                  * subvol in its directory tree.  So, this loops through
 482                  * the dentries and checks the forward refs for each subvolume
 483                  * to see if is references the subvolume where we are
 484                  * placing this new snapshot.
 485                  */
 486                 while (1) {
 487                         if (!test ||
 488                             dir == snap_src->fs_info->sb->s_root ||
 489                             test == snap_src->fs_info->sb->s_root ||
 490                             test->d_inode->i_sb != snap_src->fs_info->sb) {
 491                                 break;
 492                         }
 493                         if (S_ISLNK(test->d_inode->i_mode)) {
 494                                 printk(KERN_INFO "Btrfs symlink in snapshot "
 495                                        "path, failed\n");
 496                                 error = -EMLINK;
 497                                 btrfs_free_path(path);
 498                                 goto out_drop_write;
 499                         }
 500                         test_oid =
 501                                 BTRFS_I(test->d_inode)->root->root_key.objectid;
 502                         ret = btrfs_find_root_ref(snap_src->fs_info->tree_root,
 503                                   path, test_oid, parent_oid);
 504                         if (ret == 0) {
 505                                 printk(KERN_INFO "Btrfs snapshot creation "
 506                                        "failed, looping\n");
 507                                 error = -EMLINK;
 508                                 btrfs_free_path(path);
 509                                 goto out_drop_write;
 510                         }
 511                         btrfs_release_path(snap_src->fs_info->tree_root, path);
 512                         test = test->d_parent;
 513                 }
 514 create:
 515                 btrfs_free_path(path);
 516                 error = create_snapshot(snap_src, dentry, name, namelen);
 517         } else {
 518                 error = create_subvol(BTRFS_I(parent->dentry->d_inode)->root,
 519                                       dentry, name, namelen);
 520         }
 521         if (error)
 522                 goto out_drop_write;
 523
 524         fsnotify_mkdir(parent->dentry->d_inode, dentry);
 525 out_drop_write:
 526         mnt_drop_write(parent->mnt);
 527 out_dput:
 528         dput(dentry);
 529 out_unlock:
 530         mutex_unlock(&parent->dentry->d_inode->i_mutex);
 531         return error;
 532 }
 533
 534
 535 static int btrfs_defrag_file(struct file *file)
 536 {
 537         struct inode *inode = fdentry(file)->d_inode;
 538         struct btrfs_root *root = BTRFS_I(inode)->root;
 539         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 540         struct btrfs_ordered_extent *ordered;
 541         struct page *page;
 542         unsigned long last_index;
 543         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 544         unsigned long total_read = 0;
 545         u64 page_start;
 546         u64 page_end;
 547         unsigned long i;
 548         int ret;
 549
 550         ret = btrfs_check_data_free_space(root, inode, inode->i_size);
 551         if (ret)
 552                 return -ENOSPC;
 553
 554         mutex_lock(&inode->i_mutex);
 555         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 556         for (i = 0; i <= last_index; i++) {
 557                 if (total_read % ra_pages == 0) {
 558                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 559                                        min(last_index, i + ra_pages - 1));
 560                 }
 561                 total_read++;
 562 again:
 563                 page = grab_cache_page(inode->i_mapping, i);
 564                 if (!page)
 565                         goto out_unlock;
 566                 if (!PageUptodate(page)) {
 567                         btrfs_readpage(NULL, page);
 568                         lock_page(page);
 569                         if (!PageUptodate(page)) {
 570                                 unlock_page(page);
 571                                 page_cache_release(page);
 572                                 goto out_unlock;
 573                         }
 574                 }
 575
 576                 wait_on_page_writeback(page);
 577
 578                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 579                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 580                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 581
 582                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 583                 if (ordered) {
 584                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 585                         unlock_page(page);
 586                         page_cache_release(page);
 587                         btrfs_start_ordered_extent(inode, ordered, 1);
 588                         btrfs_put_ordered_extent(ordered);
 589                         goto again;
 590                 }
 591                 set_page_extent_mapped(page);
 592
 593                 /*
 594                  * this makes sure page_mkwrite is called on the
 595                  * page if it is dirtied again later
 596                  */
 597                 clear_page_dirty_for_io(page);
 598
 599                 btrfs_set_extent_delalloc(inode, page_start, page_end);
 600
 601                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 602                 set_page_dirty(page);
 603                 unlock_page(page);
 604                 page_cache_release(page);
 605                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 606         }
 607
 608 out_unlock:
 609         mutex_unlock(&inode->i_mutex);
 610         return 0;
 611 }
 612
 613 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 614 {
 615         u64 new_size;
 616         u64 old_size;
 617         u64 devid = 1;
 618         struct btrfs_ioctl_vol_args *vol_args;
 619         struct btrfs_trans_handle *trans;
 620         struct btrfs_device *device = NULL;
 621         char *sizestr;
 622         char *devstr = NULL;
 623         int ret = 0;
 624         int namelen;
 625         int mod = 0;
 626
 627         if (root->fs_info->sb->s_flags & MS_RDONLY)
 628                 return -EROFS;
 629
 630         if (!capable(CAP_SYS_ADMIN))
 631                 return -EPERM;
 632
 633         vol_args = memdup_user(arg, sizeof(*vol_args));
 634         if (IS_ERR(vol_args))
 635                 return PTR_ERR(vol_args);
 636
 637         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 638         namelen = strlen(vol_args->name);
 639
 640         mutex_lock(&root->fs_info->volume_mutex);
 641         sizestr = vol_args->name;
 642         devstr = strchr(sizestr, ':');
 643         if (devstr) {
 644                 char *end;
 645                 sizestr = devstr + 1;
 646                 *devstr = '\0';
 647                 devstr = vol_args->name;
 648                 devid = simple_strtoull(devstr, &end, 10);
 649                 printk(KERN_INFO "resizing devid %llu\n",
 650                        (unsigned long long)devid);
 651         }
 652         device = btrfs_find_device(root, devid, NULL, NULL);
 653         if (!device) {
 654                 printk(KERN_INFO "resizer unable to find device %llu\n",
 655                        (unsigned long long)devid);
 656                 ret = -EINVAL;
 657                 goto out_unlock;
 658         }
 659         if (!strcmp(sizestr, "max"))
 660                 new_size = device->bdev->bd_inode->i_size;
 661         else {
 662                 if (sizestr[0] == '-') {
 663                         mod = -1;
 664                         sizestr++;
 665                 } else if (sizestr[0] == '+') {
 666                         mod = 1;
 667                         sizestr++;
 668                 }
 669                 new_size = btrfs_parse_size(sizestr);
 670                 if (new_size == 0) {
 671                         ret = -EINVAL;
 672                         goto out_unlock;
 673                 }
 674         }
 675
 676         old_size = device->total_bytes;
 677
 678         if (mod < 0) {
 679                 if (new_size > old_size) {
 680                         ret = -EINVAL;
 681                         goto out_unlock;
 682                 }
 683                 new_size = old_size - new_size;
 684         } else if (mod > 0) {
 685                 new_size = old_size + new_size;
 686         }
 687
 688         if (new_size < 256 * 1024 * 1024) {
 689                 ret = -EINVAL;
 690                 goto out_unlock;
 691         }
 692         if (new_size > device->bdev->bd_inode->i_size) {
 693                 ret = -EFBIG;
 694                 goto out_unlock;
 695         }
 696
 697         do_div(new_size, root->sectorsize);
 698         new_size *= root->sectorsize;
 699
 700         printk(KERN_INFO "new size for %s is %llu\n",
 701                 device->name, (unsigned long long)new_size);
 702
 703         if (new_size > old_size) {
 704                 trans = btrfs_start_transaction(root, 1);
 705                 ret = btrfs_grow_device(trans, device, new_size);
 706                 btrfs_commit_transaction(trans, root);
 707         } else {
 708                 ret = btrfs_shrink_device(device, new_size);
 709         }
 710
 711 out_unlock:
 712         mutex_unlock(&root->fs_info->volume_mutex);
 713         kfree(vol_args);
 714         return ret;
 715 }
 716
 717 static noinline int btrfs_ioctl_snap_create(struct file *file,
 718                                             void __user *arg, int subvol)
 719 {
 720         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 721         struct btrfs_ioctl_vol_args *vol_args;
 722         struct btrfs_dir_item *di;
 723         struct btrfs_path *path;
 724         struct file *src_file;
 725         u64 root_dirid;
 726         int namelen;
 727         int ret = 0;
 728
 729         if (root->fs_info->sb->s_flags & MS_RDONLY)
 730                 return -EROFS;
 731
 732         vol_args = memdup_user(arg, sizeof(*vol_args));
 733         if (IS_ERR(vol_args))
 734                 return PTR_ERR(vol_args);
 735
 736         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 737         namelen = strlen(vol_args->name);
 738         if (strchr(vol_args->name, '/')) {
 739                 ret = -EINVAL;
 740                 goto out;
 741         }
 742
 743         path = btrfs_alloc_path();
 744         if (!path) {
 745                 ret = -ENOMEM;
 746                 goto out;
 747         }
 748
 749         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 750         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 751                             path, root_dirid,
 752                             vol_args->name, namelen, 0);
 753         btrfs_free_path(path);
 754
 755         if (di && !IS_ERR(di)) {
 756                 ret = -EEXIST;
 757                 goto out;
 758         }
 759
 760         if (IS_ERR(di)) {
 761                 ret = PTR_ERR(di);
 762                 goto out;
 763         }
 764
 765         if (subvol) {
 766                 ret = btrfs_mksubvol(&file->f_path, vol_args->name,
 767                                      file->f_path.dentry->d_inode->i_mode,
 768                                      namelen, NULL);
 769         } else {
 770                 struct inode *src_inode;
 771                 src_file = fget(vol_args->fd);
 772                 if (!src_file) {
 773                         ret = -EINVAL;
 774                         goto out;
 775                 }
 776
 777                 src_inode = src_file->f_path.dentry->d_inode;
 778                 if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
 779                         printk(KERN_INFO "btrfs: Snapshot src from "
 780                                "another FS\n");
 781                         ret = -EINVAL;
 782                         fput(src_file);
 783                         goto out;
 784                 }
 785                 ret = btrfs_mksubvol(&file->f_path, vol_args->name,
 786                              file->f_path.dentry->d_inode->i_mode,
 787                              namelen, BTRFS_I(src_inode)->root);
 788                 fput(src_file);
 789         }
 790
 791 out:
 792         kfree(vol_args);
 793         return ret;
 794 }
 795
 796 static int btrfs_ioctl_defrag(struct file *file)
 797 {
 798         struct inode *inode = fdentry(file)->d_inode;
 799         struct btrfs_root *root = BTRFS_I(inode)->root;
 800         int ret;
 801
 802         ret = mnt_want_write(file->f_path.mnt);
 803         if (ret)
 804                 return ret;
 805
 806         switch (inode->i_mode & S_IFMT) {
 807         case S_IFDIR:
 808                 if (!capable(CAP_SYS_ADMIN)) {
 809                         ret = -EPERM;
 810                         goto out;
 811                 }
 812                 btrfs_defrag_root(root, 0);
 813                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 814                 break;
 815         case S_IFREG:
 816                 if (!(file->f_mode & FMODE_WRITE)) {
 817                         ret = -EINVAL;
 818                         goto out;
 819                 }
 820                 btrfs_defrag_file(file);
 821                 break;
 822         }
 823 out:
 824         mnt_drop_write(file->f_path.mnt);
 825         return ret;
 826 }
 827
 828 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 829 {
 830         struct btrfs_ioctl_vol_args *vol_args;
 831         int ret;
 832
 833         if (!capable(CAP_SYS_ADMIN))
 834                 return -EPERM;
 835
 836         vol_args = memdup_user(arg, sizeof(*vol_args));
 837         if (IS_ERR(vol_args))
 838                 return PTR_ERR(vol_args);
 839
 840         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 841         ret = btrfs_init_new_device(root, vol_args->name);
 842
 843         kfree(vol_args);
 844         return ret;
 845 }
 846
 847 static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 848 {
 849         struct btrfs_ioctl_vol_args *vol_args;
 850         int ret;
 851
 852         if (!capable(CAP_SYS_ADMIN))
 853                 return -EPERM;
 854
 855         if (root->fs_info->sb->s_flags & MS_RDONLY)
 856                 return -EROFS;
 857
 858         vol_args = memdup_user(arg, sizeof(*vol_args));
 859         if (IS_ERR(vol_args))
 860                 return PTR_ERR(vol_args);
 861
 862         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 863         ret = btrfs_rm_device(root, vol_args->name);
 864
 865         kfree(vol_args);
 866         return ret;
 867 }
 868
 869 static long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 870                 u64 off, u64 olen, u64 destoff)
 871 {
 872         struct inode *inode = fdentry(file)->d_inode;
 873         struct btrfs_root *root = BTRFS_I(inode)->root;
 874         struct file *src_file;
 875         struct inode *src;
 876         struct btrfs_trans_handle *trans;
 877         struct btrfs_path *path;
 878         struct extent_buffer *leaf;
 879         char *buf;
 880         struct btrfs_key key;
 881         u32 nritems;
 882         int slot;
 883         int ret;
 884         u64 len = olen;
 885         u64 bs = root->fs_info->sb->s_blocksize;
 886         u64 hint_byte;
 887
 888         /*
 889          * TODO:
 890          * - split compressed inline extents.  annoying: we need to
 891          *   decompress into destination's address_space (the file offset
 892          *   may change, so source mapping won't do), then recompress (or
 893          *   otherwise reinsert) a subrange.
 894          * - allow ranges within the same file to be cloned (provided
 895          *   they don't overlap)?
 896          */
 897
 898         /* the destination must be opened for writing */
 899         if (!(file->f_mode & FMODE_WRITE))
 900                 return -EINVAL;
 901
 902         ret = mnt_want_write(file->f_path.mnt);
 903         if (ret)
 904                 return ret;
 905
 906         src_file = fget(srcfd);
 907         if (!src_file) {
 908                 ret = -EBADF;
 909                 goto out_drop_write;
 910         }
 911         src = src_file->f_dentry->d_inode;
 912
 913         ret = -EINVAL;
 914         if (src == inode)
 915                 goto out_fput;
 916
 917         ret = -EISDIR;
 918         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
 919                 goto out_fput;
 920
 921         ret = -EXDEV;
 922         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
 923                 goto out_fput;
 924
 925         ret = -ENOMEM;
 926         buf = vmalloc(btrfs_level_size(root, 0));
 927         if (!buf)
 928                 goto out_fput;
 929
 930         path = btrfs_alloc_path();
 931         if (!path) {
 932                 vfree(buf);
 933                 goto out_fput;
 934         }
 935         path->reada = 2;
 936
 937         if (inode < src) {
 938                 mutex_lock(&inode->i_mutex);
 939                 mutex_lock(&src->i_mutex);
 940         } else {
 941                 mutex_lock(&src->i_mutex);
 942                 mutex_lock(&inode->i_mutex);
 943         }
 944
 945         /* determine range to clone */
 946         ret = -EINVAL;
 947         if (off >= src->i_size || off + len > src->i_size)
 948                 goto out_unlock;
 949         if (len == 0)
 950                 olen = len = src->i_size - off;
 951         /* if we extend to eof, continue to block boundary */
 952         if (off + len == src->i_size)
 953                 len = ((src->i_size + bs-1) & ~(bs-1))
 954                         - off;
 955
 956         /* verify the end result is block aligned */
 957         if ((off & (bs-1)) ||
 958             ((off + len) & (bs-1)))
 959                 goto out_unlock;
 960
 961         /* do any pending delalloc/csum calc on src, one way or
 962            another, and lock file content */
 963         while (1) {
 964                 struct btrfs_ordered_extent *ordered;
 965                 lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
 966                 ordered = btrfs_lookup_first_ordered_extent(inode, off+len);
 967                 if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
 968                         break;
 969                 unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
 970                 if (ordered)
 971                         btrfs_put_ordered_extent(ordered);
 972                 btrfs_wait_ordered_range(src, off, off+len);
 973         }
 974
 975         trans = btrfs_start_transaction(root, 1);
 976         BUG_ON(!trans);
 977
 978         /* punch hole in destination first */
 979         btrfs_drop_extents(trans, root, inode, off, off + len,
 980                            off + len, 0, &hint_byte);
 981
 982         /* clone data */
 983         key.objectid = src->i_ino;
 984         key.type = BTRFS_EXTENT_DATA_KEY;
 985         key.offset = 0;
 986
 987         while (1) {
 988                 /*
 989                  * note the key will change type as we walk through the
 990                  * tree.
 991                  */
 992                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 993                 if (ret < 0)
 994                         goto out;
 995
 996                 nritems = btrfs_header_nritems(path->nodes[0]);
 997                 if (path->slots[0] >= nritems) {
 998                         ret = btrfs_next_leaf(root, path);
 999                         if (ret < 0)
1000                                 goto out;
1001                         if (ret > 0)
1002                                 break;
1003                         nritems = btrfs_header_nritems(path->nodes[0]);
1004                 }
1005                 leaf = path->nodes[0];
1006                 slot = path->slots[0];
1007
1008                 btrfs_item_key_to_cpu(leaf, &key, slot);
1009                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
1010                     key.objectid != src->i_ino)
1011                         break;
1012
1013                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
1014                         struct btrfs_file_extent_item *extent;
1015                         int type;
1016                         u32 size;
1017                         struct btrfs_key new_key;
1018                         u64 disko = 0, diskl = 0;
1019                         u64 datao = 0, datal = 0;
1020                         u8 comp;
1021
1022                         size = btrfs_item_size_nr(leaf, slot);
1023                         read_extent_buffer(leaf, buf,
1024                                            btrfs_item_ptr_offset(leaf, slot),
1025                                            size);
1026
1027                         extent = btrfs_item_ptr(leaf, slot,
1028                                                 struct btrfs_file_extent_item);
1029                         comp = btrfs_file_extent_compression(leaf, extent);
1030                         type = btrfs_file_extent_type(leaf, extent);
1031                         if (type == BTRFS_FILE_EXTENT_REG) {
1032                                 disko = btrfs_file_extent_disk_bytenr(leaf,
1033                                                                       extent);
1034                                 diskl = btrfs_file_extent_disk_num_bytes(leaf,
1035                                                                  extent);
1036                                 datao = btrfs_file_extent_offset(leaf, extent);
1037                                 datal = btrfs_file_extent_num_bytes(leaf,
1038                                                                     extent);
1039                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1040                                 /* take upper bound, may be compressed */
1041                                 datal = btrfs_file_extent_ram_bytes(leaf,
1042                                                                     extent);
1043                         }
1044                         btrfs_release_path(root, path);
1045
1046                         if (key.offset + datal < off ||
1047                             key.offset >= off+len)
1048                                 goto next;
1049
1050                         memcpy(&new_key, &key, sizeof(new_key));
1051                         new_key.objectid = inode->i_ino;
1052                         new_key.offset = key.offset + destoff - off;
1053
1054                         if (type == BTRFS_FILE_EXTENT_REG) {
1055                                 ret = btrfs_insert_empty_item(trans, root, path,
1056                                                               &new_key, size);
1057                                 if (ret)
1058                                         goto out;
1059
1060                                 leaf = path->nodes[0];
1061                                 slot = path->slots[0];
1062                                 write_extent_buffer(leaf, buf,
1063                                             btrfs_item_ptr_offset(leaf, slot),
1064                                             size);
1065
1066                                 extent = btrfs_item_ptr(leaf, slot,
1067                                                 struct btrfs_file_extent_item);
1068
1069                                 if (off > key.offset) {
1070                                         datao += off - key.offset;
1071                                         datal -= off - key.offset;
1072                                 }
1073                                 if (key.offset + datao + datal + key.offset >
1074                                     off + len)
1075                                         datal = off + len - key.offset - datao;
1076                                 /* disko == 0 means it's a hole */
1077                                 if (!disko)
1078                                         datao = 0;
1079
1080                                 btrfs_set_file_extent_offset(leaf, extent,
1081                                                              datao);
1082                                 btrfs_set_file_extent_num_bytes(leaf, extent,
1083                                                                 datal);
1084                                 if (disko) {
1085                                         inode_add_bytes(inode, datal);
1086                                         ret = btrfs_inc_extent_ref(trans, root,
1087                                                         disko, diskl, 0,
1088                                                         root->root_key.objectid,
1089                                                         inode->i_ino,
1090                                                         new_key.offset - datao);
1091                                         BUG_ON(ret);
1092                                 }
1093                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1094                                 u64 skip = 0;
1095                                 u64 trim = 0;
1096                                 if (off > key.offset) {
1097                                         skip = off - key.offset;
1098                                         new_key.offset += skip;
1099                                 }
1100
1101                                 if (key.offset + datal > off+len)
1102                                         trim = key.offset + datal - (off+len);
1103
1104                                 if (comp && (skip || trim)) {
1105                                         ret = -EINVAL;
1106                                         goto out;
1107                                 }
1108                                 size -= skip + trim;
1109                                 datal -= skip + trim;
1110                                 ret = btrfs_insert_empty_item(trans, root, path,
1111                                                               &new_key, size);
1112                                 if (ret)
1113                                         goto out;
1114
1115                                 if (skip) {
1116                                         u32 start =
1117                                           btrfs_file_extent_calc_inline_size(0);
1118                                         memmove(buf+start, buf+start+skip,
1119                                                 datal);
1120                                 }
1121
1122                                 leaf = path->nodes[0];
1123                                 slot = path->slots[0];
1124                                 write_extent_buffer(leaf, buf,
1125                                             btrfs_item_ptr_offset(leaf, slot),
1126                                             size);
1127                                 inode_add_bytes(inode, datal);
1128                         }
1129
1130                         btrfs_mark_buffer_dirty(leaf);
1131                 }
1132
1133 next:
1134                 btrfs_release_path(root, path);
1135                 key.offset++;
1136         }
1137         ret = 0;
1138 out:
1139         btrfs_release_path(root, path);
1140         if (ret == 0) {
1141                 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1142                 if (destoff + olen > inode->i_size)
1143                         btrfs_i_size_write(inode, destoff + olen);
1144                 BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
1145                 ret = btrfs_update_inode(trans, root, inode);
1146         }
1147         btrfs_end_transaction(trans, root);
1148         unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1149         if (ret)
1150                 vmtruncate(inode, 0);
1151 out_unlock:
1152         mutex_unlock(&src->i_mutex);
1153         mutex_unlock(&inode->i_mutex);
1154         vfree(buf);
1155         btrfs_free_path(path);
1156 out_fput:
1157         fput(src_file);
1158 out_drop_write:
1159         mnt_drop_write(file->f_path.mnt);
1160         return ret;
1161 }
1162
1163 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
1164 {
1165         struct btrfs_ioctl_clone_range_args args;
1166
1167         if (copy_from_user(&args, argp, sizeof(args)))
1168                 return -EFAULT;
1169         return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
1170                                  args.src_length, args.dest_offset);
1171 }
1172
1173 /*
1174  * there are many ways the trans_start and trans_end ioctls can lead
1175  * to deadlocks.  They should only be used by applications that
1176  * basically own the machine, and have a very in depth understanding
1177  * of all the possible deadlocks and enospc problems.
1178  */
1179 static long btrfs_ioctl_trans_start(struct file *file)
1180 {
1181         struct inode *inode = fdentry(file)->d_inode;
1182         struct btrfs_root *root = BTRFS_I(inode)->root;
1183         struct btrfs_trans_handle *trans;
1184         int ret = 0;
1185
1186         if (!capable(CAP_SYS_ADMIN))
1187                 return -EPERM;
1188
1189         if (file->private_data) {
1190                 ret = -EINPROGRESS;
1191                 goto out;
1192         }
1193
1194         ret = mnt_want_write(file->f_path.mnt);
1195         if (ret)
1196                 goto out;
1197
1198         mutex_lock(&root->fs_info->trans_mutex);
1199         root->fs_info->open_ioctl_trans++;
1200         mutex_unlock(&root->fs_info->trans_mutex);
1201
1202         trans = btrfs_start_ioctl_transaction(root, 0);
1203         if (trans)
1204                 file->private_data = trans;
1205         else
1206                 ret = -ENOMEM;
1207         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
1208 out:
1209         return ret;
1210 }
1211
1212 /*
1213  * there are many ways the trans_start and trans_end ioctls can lead
1214  * to deadlocks.  They should only be used by applications that
1215  * basically own the machine, and have a very in depth understanding
1216  * of all the possible deadlocks and enospc problems.
1217  */
1218 long btrfs_ioctl_trans_end(struct file *file)
1219 {
1220         struct inode *inode = fdentry(file)->d_inode;
1221         struct btrfs_root *root = BTRFS_I(inode)->root;
1222         struct btrfs_trans_handle *trans;
1223         int ret = 0;
1224
1225         trans = file->private_data;
1226         if (!trans) {
1227                 ret = -EINVAL;
1228                 goto out;
1229         }
1230         btrfs_end_transaction(trans, root);
1231         file->private_data = NULL;
1232
1233         mutex_lock(&root->fs_info->trans_mutex);
1234         root->fs_info->open_ioctl_trans--;
1235         mutex_unlock(&root->fs_info->trans_mutex);
1236
1237         mnt_drop_write(file->f_path.mnt);
1238
1239 out:
1240         return ret;
1241 }
1242
1243 long btrfs_ioctl(struct file *file, unsigned int
1244                 cmd, unsigned long arg)
1245 {
1246         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
1247         void __user *argp = (void __user *)arg;
1248
1249         switch (cmd) {
1250         case FS_IOC_GETFLAGS:
1251                 return btrfs_ioctl_getflags(file, argp);
1252         case FS_IOC_SETFLAGS:
1253                 return btrfs_ioctl_setflags(file, argp);
1254         case FS_IOC_GETVERSION:
1255                 return btrfs_ioctl_getversion(file, argp);
1256         case BTRFS_IOC_SNAP_CREATE:
1257                 return btrfs_ioctl_snap_create(file, argp, 0);
1258         case BTRFS_IOC_SUBVOL_CREATE:
1259                 return btrfs_ioctl_snap_create(file, argp, 1);
1260         case BTRFS_IOC_DEFRAG:
1261                 return btrfs_ioctl_defrag(file);
1262         case BTRFS_IOC_RESIZE:
1263                 return btrfs_ioctl_resize(root, argp);
1264         case BTRFS_IOC_ADD_DEV:
1265                 return btrfs_ioctl_add_dev(root, argp);
1266         case BTRFS_IOC_RM_DEV:
1267                 return btrfs_ioctl_rm_dev(root, argp);
1268         case BTRFS_IOC_BALANCE:
1269                 return btrfs_balance(root->fs_info->dev_root);
1270         case BTRFS_IOC_CLONE:
1271                 return btrfs_ioctl_clone(file, arg, 0, 0, 0);
1272         case BTRFS_IOC_CLONE_RANGE:
1273                 return btrfs_ioctl_clone_range(file, argp);
1274         case BTRFS_IOC_TRANS_START:
1275                 return btrfs_ioctl_trans_start(file);
1276         case BTRFS_IOC_TRANS_END:
1277                 return btrfs_ioctl_trans_end(file);
1278         case BTRFS_IOC_SYNC:
1279                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
1280                 return 0;
1281         }
1282
1283         return -ENOTTY;
1284 }