source3/modules/vfs_btrfs.c

   1 /*
   2  * Module to make use of awesome Btrfs features
   3  *
   4  * Copyright (C) David Disseldorp 2011-2013
   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 3 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, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/ioctl.h>
  21 #include <linux/fs.h>
  22 #include <sys/ioctl.h>
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25 #include <dirent.h>
  26 #include <libgen.h>
  27 #include "system/filesys.h"
  28 #include "includes.h"
  29 #include "smbd/smbd.h"
  30 #include "librpc/gen_ndr/smbXsrv.h"
  31 #include "librpc/gen_ndr/ioctl.h"
  32 #include "lib/util/tevent_ntstatus.h"
  33
  34 static uint32_t btrfs_fs_capabilities(struct vfs_handle_struct *handle,
  35                                       enum timestamp_set_resolution *_ts_res)
  36 {
  37         uint32_t fs_capabilities;
  38         enum timestamp_set_resolution ts_res;
  39
  40         /* inherit default capabilities, expose compression support */
  41         fs_capabilities = SMB_VFS_NEXT_FS_CAPABILITIES(handle, &ts_res);
  42         fs_capabilities |= FILE_FILE_COMPRESSION;
  43         *_ts_res = ts_res;
  44
  45         return fs_capabilities;
  46 }
  47
  48 #define SHADOW_COPY_PREFIX "@GMT-"      /* vfs_shadow_copy format */
  49 #define SHADOW_COPY_PATH_FORMAT "@GMT-%Y.%m.%d-%H.%M.%S"
  50
  51 #define BTRFS_SUBVOL_RDONLY             (1ULL << 1)
  52 #define BTRFS_SUBVOL_NAME_MAX           4039
  53 #define BTRFS_PATH_NAME_MAX             4087
  54 struct btrfs_ioctl_vol_args_v2 {
  55         int64_t fd;
  56         uint64_t transid;
  57         uint64_t flags;
  58         uint64_t unused[4];
  59         char name[BTRFS_SUBVOL_NAME_MAX + 1];
  60 };
  61 struct btrfs_ioctl_vol_args {
  62         int64_t fd;
  63         char name[BTRFS_PATH_NAME_MAX + 1];
  64 };
  65
  66 struct btrfs_ioctl_clone_range_args {
  67         int64_t src_fd;
  68         uint64_t src_offset;
  69         uint64_t src_length;
  70         uint64_t dest_offset;
  71 };
  72
  73 #define BTRFS_IOCTL_MAGIC 0x94
  74 #define BTRFS_IOC_CLONE_RANGE _IOW(BTRFS_IOCTL_MAGIC, 13, \
  75                                    struct btrfs_ioctl_clone_range_args)
  76 #define BTRFS_IOC_SNAP_DESTROY _IOW(BTRFS_IOCTL_MAGIC, 15, \
  77                                     struct btrfs_ioctl_vol_args)
  78 #define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \
  79                                       struct btrfs_ioctl_vol_args_v2)
  80
  81 struct btrfs_cc_state {
  82         struct vfs_handle_struct *handle;
  83         off_t copied;
  84         struct tevent_req *subreq;      /* non-null if passed to next VFS fn */
  85 };
  86 static void btrfs_copy_chunk_done(struct tevent_req *subreq);
  87
  88 static struct tevent_req *btrfs_copy_chunk_send(struct vfs_handle_struct *handle,
  89                                                 TALLOC_CTX *mem_ctx,
  90                                                 struct tevent_context *ev,
  91                                                 struct files_struct *src_fsp,
  92                                                 off_t src_off,
  93                                                 struct files_struct *dest_fsp,
  94                                                 off_t dest_off,
  95                                                 off_t num)
  96 {
  97         struct tevent_req *req;
  98         struct btrfs_cc_state *cc_state;
  99         struct btrfs_ioctl_clone_range_args cr_args;
 100         struct lock_struct src_lck;
 101         struct lock_struct dest_lck;
 102         int ret;
 103         NTSTATUS status;
 104
 105         req = tevent_req_create(mem_ctx, &cc_state, struct btrfs_cc_state);
 106         if (req == NULL) {
 107                 return NULL;
 108         }
 109         cc_state->handle = handle;
 110
 111         if (num == 0) {
 112                 /*
 113                  * With a @src_length of zero, BTRFS_IOC_CLONE_RANGE clones
 114                  * all data from @src_offset->EOF! This is certainly not what
 115                  * the caller expects, and not what vfs_default does.
 116                  */
 117                 cc_state->subreq = SMB_VFS_NEXT_COPY_CHUNK_SEND(handle,
 118                                                                 cc_state, ev,
 119                                                                 src_fsp,
 120                                                                 src_off,
 121                                                                 dest_fsp,
 122                                                                 dest_off, num);
 123                 if (tevent_req_nomem(cc_state->subreq, req)) {
 124                         return tevent_req_post(req, ev);
 125                 }
 126                 tevent_req_set_callback(cc_state->subreq,
 127                                         btrfs_copy_chunk_done,
 128                                         req);
 129                 return req;
 130         }
 131
 132         status = vfs_stat_fsp(src_fsp);
 133         if (tevent_req_nterror(req, status)) {
 134                 return tevent_req_post(req, ev);
 135         }
 136
 137         if (src_fsp->fsp_name->st.st_ex_size < src_off + num) {
 138                 /* [MS-SMB2] Handling a Server-Side Data Copy Request */
 139                 tevent_req_nterror(req, NT_STATUS_INVALID_VIEW_SIZE);
 140                 return tevent_req_post(req, ev);
 141         }
 142
 143         if (src_fsp->op == NULL || dest_fsp->op == NULL) {
 144                 tevent_req_nterror(req, NT_STATUS_INTERNAL_ERROR);
 145                 return tevent_req_post(req, ev);
 146         }
 147
 148         init_strict_lock_struct(src_fsp,
 149                                 src_fsp->op->global->open_persistent_id,
 150                                 src_off,
 151                                 num,
 152                                 READ_LOCK,
 153                                 &src_lck);
 154         init_strict_lock_struct(dest_fsp,
 155                                 dest_fsp->op->global->open_persistent_id,
 156                                 dest_off,
 157                                 num,
 158                                 WRITE_LOCK,
 159                                 &dest_lck);
 160
 161         if (!SMB_VFS_STRICT_LOCK(src_fsp->conn, src_fsp, &src_lck)) {
 162                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 163                 return tevent_req_post(req, ev);
 164         }
 165         if (!SMB_VFS_STRICT_LOCK(dest_fsp->conn, dest_fsp, &dest_lck)) {
 166                 SMB_VFS_STRICT_UNLOCK(src_fsp->conn, src_fsp, &src_lck);
 167                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 168                 return tevent_req_post(req, ev);
 169         }
 170
 171         ZERO_STRUCT(cr_args);
 172         cr_args.src_fd = src_fsp->fh->fd;
 173         cr_args.src_offset = (uint64_t)src_off;
 174         cr_args.dest_offset = (uint64_t)dest_off;
 175         cr_args.src_length = (uint64_t)num;
 176
 177         ret = ioctl(dest_fsp->fh->fd, BTRFS_IOC_CLONE_RANGE, &cr_args);
 178         SMB_VFS_STRICT_UNLOCK(dest_fsp->conn, dest_fsp, &dest_lck);
 179         SMB_VFS_STRICT_UNLOCK(src_fsp->conn, src_fsp, &src_lck);
 180         if (ret < 0) {
 181                 /*
 182                  * BTRFS_IOC_CLONE_RANGE only supports 'sectorsize' aligned
 183                  * cloning. Which is 4096 by default, therefore fall back to
 184                  * manual read/write on failure.
 185                  */
 186                 DEBUG(5, ("BTRFS_IOC_CLONE_RANGE failed: %s, length %llu, "
 187                           "src fd: %lld off: %llu, dest fd: %d off: %llu\n",
 188                           strerror(errno),
 189                           (unsigned long long)cr_args.src_length,
 190                           (long long)cr_args.src_fd,
 191                           (unsigned long long)cr_args.src_offset,
 192                           dest_fsp->fh->fd,
 193                           (unsigned long long)cr_args.dest_offset));
 194                 cc_state->subreq = SMB_VFS_NEXT_COPY_CHUNK_SEND(handle,
 195                                                                 cc_state, ev,
 196                                                                 src_fsp,
 197                                                                 src_off,
 198                                                                 dest_fsp,
 199                                                                 dest_off, num);
 200                 if (tevent_req_nomem(cc_state->subreq, req)) {
 201                         return tevent_req_post(req, ev);
 202                 }
 203                 /* wait for subreq completion */
 204                 tevent_req_set_callback(cc_state->subreq,
 205                                         btrfs_copy_chunk_done,
 206                                         req);
 207                 return req;
 208         }
 209
 210         DEBUG(5, ("BTRFS_IOC_CLONE_RANGE returned %d\n", ret));
 211         /* BTRFS_IOC_CLONE_RANGE is all or nothing */
 212         cc_state->copied = num;
 213         tevent_req_done(req);
 214         return tevent_req_post(req, ev);
 215 }
 216
 217 /* only used if the request is passed through to next VFS module */
 218 static void btrfs_copy_chunk_done(struct tevent_req *subreq)
 219 {
 220         struct tevent_req *req = tevent_req_callback_data(
 221                 subreq, struct tevent_req);
 222         struct btrfs_cc_state *cc_state = tevent_req_data(req,
 223                                                         struct btrfs_cc_state);
 224         NTSTATUS status;
 225
 226         status = SMB_VFS_NEXT_COPY_CHUNK_RECV(cc_state->handle,
 227                                               cc_state->subreq,
 228                                               &cc_state->copied);
 229         if (tevent_req_nterror(req, status)) {
 230                 return;
 231         }
 232         tevent_req_done(req);
 233 }
 234
 235 static NTSTATUS btrfs_copy_chunk_recv(struct vfs_handle_struct *handle,
 236                                       struct tevent_req *req,
 237                                       off_t *copied)
 238 {
 239         NTSTATUS status;
 240         struct btrfs_cc_state *cc_state = tevent_req_data(req,
 241                                                         struct btrfs_cc_state);
 242
 243         if (tevent_req_is_nterror(req, &status)) {
 244                 DEBUG(4, ("server side copy chunk failed: %s\n",
 245                           nt_errstr(status)));
 246                 tevent_req_received(req);
 247                 return status;
 248         }
 249
 250         DEBUG(10, ("server side copy chunk copied %llu\n",
 251                    (unsigned long long)cc_state->copied));
 252         *copied = cc_state->copied;
 253         tevent_req_received(req);
 254         return NT_STATUS_OK;
 255 }
 256
 257 /*
 258  * caller must pass a non-null fsp or smb_fname. If fsp is null, then
 259  * fall back to opening the corresponding file to issue the ioctl.
 260  */
 261 static NTSTATUS btrfs_get_compression(struct vfs_handle_struct *handle,
 262                                       TALLOC_CTX *mem_ctx,
 263                                       struct files_struct *fsp,
 264                                       struct smb_filename *smb_fname,
 265                                       uint16_t *_compression_fmt)
 266 {
 267         int ret;
 268         long flags = 0;
 269         int fd;
 270         bool opened = false;
 271         NTSTATUS status;
 272         DIR *dir = NULL;
 273
 274         if ((fsp != NULL) && (fsp->fh->fd != -1)) {
 275                 fd = fsp->fh->fd;
 276         } else if (smb_fname != NULL) {
 277                 if (S_ISDIR(smb_fname->st.st_ex_mode)) {
 278                         dir = opendir(smb_fname->base_name);
 279                         if (dir == NULL) {
 280                                 return NT_STATUS_UNSUCCESSFUL;
 281                         }
 282                         opened = true;
 283                         fd = dirfd(dir);
 284                         if (fd < 0) {
 285                                 status = NT_STATUS_UNSUCCESSFUL;
 286                                 goto err_close;
 287                         }
 288                 } else {
 289                         fd = open(smb_fname->base_name, O_RDONLY);
 290                         if (fd < 0) {
 291                                 return NT_STATUS_UNSUCCESSFUL;
 292                         }
 293                         opened = true;
 294                 }
 295         } else {
 296                 return NT_STATUS_INVALID_PARAMETER;
 297         }
 298
 299         ret = ioctl(fd, FS_IOC_GETFLAGS, &flags);
 300         if (ret < 0) {
 301                 DEBUG(1, ("FS_IOC_GETFLAGS failed: %s, fd %lld\n",
 302                           strerror(errno), (long long)fd));
 303                 status = map_nt_error_from_unix(errno);
 304                 goto err_close;
 305         }
 306         if (flags & FS_COMPR_FL) {
 307                 *_compression_fmt = COMPRESSION_FORMAT_LZNT1;
 308         } else {
 309                 *_compression_fmt = COMPRESSION_FORMAT_NONE;
 310         }
 311         status = NT_STATUS_OK;
 312 err_close:
 313         if (opened) {
 314                 if (dir != NULL) {
 315                         closedir(dir);
 316                 } else {
 317                         close(fd);
 318                 }
 319         }
 320
 321         return status;
 322 }
 323
 324 static NTSTATUS btrfs_set_compression(struct vfs_handle_struct *handle,
 325                                       TALLOC_CTX *mem_ctx,
 326                                       struct files_struct *fsp,
 327                                       uint16_t compression_fmt)
 328 {
 329         int ret;
 330         long flags = 0;
 331         int fd;
 332         NTSTATUS status;
 333
 334         if ((fsp == NULL) || (fsp->fh->fd == -1)) {
 335                 status = NT_STATUS_INVALID_PARAMETER;
 336                 goto err_out;
 337         }
 338         fd = fsp->fh->fd;
 339
 340         ret = ioctl(fd, FS_IOC_GETFLAGS, &flags);
 341         if (ret < 0) {
 342                 DEBUG(1, ("FS_IOC_GETFLAGS failed: %s, fd %d\n",
 343                           strerror(errno), fd));
 344                 status = map_nt_error_from_unix(errno);
 345                 goto err_out;
 346         }
 347
 348         if (compression_fmt == COMPRESSION_FORMAT_NONE) {
 349                 DEBUG(5, ("setting compression\n"));
 350                 flags &= (~FS_COMPR_FL);
 351         } else if ((compression_fmt == COMPRESSION_FORMAT_DEFAULT)
 352                 || (compression_fmt == COMPRESSION_FORMAT_LZNT1)) {
 353                 DEBUG(5, ("clearing compression\n"));
 354                 flags |= FS_COMPR_FL;
 355         } else {
 356                 DEBUG(1, ("invalid compression format 0x%x\n",
 357                           (int)compression_fmt));
 358                 status = NT_STATUS_INVALID_PARAMETER;
 359                 goto err_out;
 360         }
 361
 362         ret = ioctl(fd, FS_IOC_SETFLAGS, &flags);
 363         if (ret < 0) {
 364                 DEBUG(1, ("FS_IOC_SETFLAGS failed: %s, fd %d\n",
 365                           strerror(errno), fd));
 366                 status = map_nt_error_from_unix(errno);
 367                 goto err_out;
 368         }
 369         status = NT_STATUS_OK;
 370 err_out:
 371         return status;
 372 }
 373
 374 /*
 375  * Check whether a path can be shadow copied. Return the base volume, allowing
 376  * the caller to determine if multiple paths lie on the same base volume.
 377  */
 378 #define BTRFS_INODE_SUBVOL 256
 379 static NTSTATUS btrfs_snap_check_path(struct vfs_handle_struct *handle,
 380                                       TALLOC_CTX *mem_ctx,
 381                                       const char *service_path,
 382                                       char **base_volume)
 383 {
 384         struct stat st;
 385         char *base;
 386
 387         if (!lp_parm_bool(SNUM(handle->conn),
 388                          "btrfs", "manipulate snapshots", false)) {
 389                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 390                 return SMB_VFS_NEXT_SNAP_CHECK_PATH(handle, mem_ctx,
 391                                                     service_path, base_volume);
 392         }
 393
 394         /* btrfs userspace uses this logic to confirm subvolume */
 395         if (stat(service_path, &st) < 0) {
 396                 return NT_STATUS_NOT_SUPPORTED;
 397         }
 398         if ((st.st_ino != BTRFS_INODE_SUBVOL) || !S_ISDIR(st.st_mode)) {
 399                 DEBUG(0, ("%s not a btrfs subvolume, snapshots not available\n",
 400                           service_path));
 401                 return NT_STATUS_NOT_SUPPORTED;
 402         }
 403
 404         /* we "snapshot" the service path itself */
 405         base = talloc_strdup(mem_ctx, service_path);
 406         if (base == NULL) {
 407                 return NT_STATUS_NO_MEMORY;
 408         }
 409         *base_volume = base;
 410
 411         return NT_STATUS_OK;
 412 }
 413
 414 static NTSTATUS btrfs_gen_snap_dest_path(TALLOC_CTX *mem_ctx,
 415                                          const char *src_path,
 416                                          time_t *tstamp,
 417                                          char **dest_path, char **subvolume)
 418 {
 419         struct tm t_gmt;
 420         char time_str[50];
 421         size_t tlen;
 422
 423         gmtime_r(tstamp, &t_gmt);
 424
 425         tlen = strftime(time_str, ARRAY_SIZE(time_str),
 426                         SHADOW_COPY_PATH_FORMAT, &t_gmt);
 427         if (tlen <= 0) {
 428                 return NT_STATUS_UNSUCCESSFUL;
 429         }
 430
 431         *dest_path = talloc_strdup(mem_ctx, src_path);
 432         *subvolume = talloc_strdup(mem_ctx, time_str);
 433         if ((*dest_path == NULL) || (*subvolume == NULL)) {
 434                 return NT_STATUS_NO_MEMORY;
 435         }
 436
 437         return NT_STATUS_OK;
 438 }
 439
 440 static NTSTATUS btrfs_snap_create(struct vfs_handle_struct *handle,
 441                                   TALLOC_CTX *mem_ctx,
 442                                   const char *base_volume,
 443                                   time_t *tstamp,
 444                                   bool rw,
 445                                   char **_base_path,
 446                                   char **_snap_path)
 447 {
 448         struct btrfs_ioctl_vol_args_v2 ioctl_arg;
 449         DIR *src_dir;
 450         DIR *dest_dir;
 451         int src_fd;
 452         int dest_fd;
 453         char *dest_path = NULL;
 454         char *dest_subvolume = NULL;
 455         int ret;
 456         NTSTATUS status;
 457         char *base_path;
 458         char *snap_path;
 459         TALLOC_CTX *tmp_ctx;
 460         int saved_errno;
 461         size_t len;
 462
 463         if (!lp_parm_bool(SNUM(handle->conn),
 464                           "btrfs", "manipulate snapshots", false)) {
 465                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 466                 return SMB_VFS_NEXT_SNAP_CREATE(handle, mem_ctx, base_volume,
 467                                                 tstamp, rw, _base_path,
 468                                                 _snap_path);
 469         }
 470
 471         tmp_ctx = talloc_new(mem_ctx);
 472         if (tmp_ctx == NULL) {
 473                 return NT_STATUS_NO_MEMORY;
 474         }
 475
 476         base_path = talloc_strdup(tmp_ctx, base_volume);
 477         if (base_path == NULL) {
 478                 talloc_free(tmp_ctx);
 479                 return NT_STATUS_NO_MEMORY;
 480         }
 481
 482         status = btrfs_gen_snap_dest_path(tmp_ctx, base_volume, tstamp,
 483                                           &dest_path, &dest_subvolume);
 484         if (!NT_STATUS_IS_OK(status)) {
 485                 talloc_free(tmp_ctx);
 486                 return status;
 487         }
 488
 489         snap_path = talloc_asprintf(tmp_ctx, "%s/%s", dest_path,
 490                                     dest_subvolume);
 491         if (snap_path == NULL) {
 492                 talloc_free(tmp_ctx);
 493                 return NT_STATUS_NO_MEMORY;
 494         }
 495
 496         src_dir = opendir(base_volume);
 497         if (src_dir == NULL) {
 498                 DEBUG(0, ("snap src %s open failed: %s\n",
 499                           base_volume, strerror(errno)));
 500                 status = map_nt_error_from_unix(errno);
 501                 talloc_free(tmp_ctx);
 502                 return status;
 503         }
 504         src_fd = dirfd(src_dir);
 505         if (src_fd < 0) {
 506                 status = map_nt_error_from_unix(errno);
 507                 closedir(src_dir);
 508                 talloc_free(tmp_ctx);
 509                 return status;
 510         }
 511
 512         dest_dir = opendir(dest_path);
 513         if (dest_dir == NULL) {
 514                 DEBUG(0, ("snap dest %s open failed: %s\n",
 515                           dest_path, strerror(errno)));
 516                 status = map_nt_error_from_unix(errno);
 517                 closedir(src_dir);
 518                 talloc_free(tmp_ctx);
 519                 return status;
 520         }
 521         dest_fd = dirfd(dest_dir);
 522         if (dest_fd < 0) {
 523                 status = map_nt_error_from_unix(errno);
 524                 closedir(src_dir);
 525                 closedir(dest_dir);
 526                 talloc_free(tmp_ctx);
 527                 return status;
 528         }
 529
 530         /* avoid zeroing the entire struct here, name is 4k */
 531         ioctl_arg.fd = src_fd;
 532         ioctl_arg.transid = 0;
 533         ioctl_arg.flags = (rw == false) ? BTRFS_SUBVOL_RDONLY : 0;
 534         memset(ioctl_arg.unused, 0, ARRAY_SIZE(ioctl_arg.unused));
 535         len = strlcpy(ioctl_arg.name, dest_subvolume,
 536                       ARRAY_SIZE(ioctl_arg.name));
 537         if (len >= ARRAY_SIZE(ioctl_arg.name)) {
 538                 DEBUG(1, ("subvolume name too long for SNAP_CREATE ioctl\n"));
 539                 closedir(src_dir);
 540                 closedir(dest_dir);
 541                 talloc_free(tmp_ctx);
 542                 return NT_STATUS_INVALID_PARAMETER;
 543         }
 544
 545         become_root();
 546         ret = ioctl(dest_fd, BTRFS_IOC_SNAP_CREATE_V2, &ioctl_arg);
 547         saved_errno = errno;
 548         unbecome_root();
 549         if (ret < 0) {
 550                 DEBUG(0, ("%s -> %s(%s) BTRFS_IOC_SNAP_CREATE_V2 failed: %s\n",
 551                           base_volume, dest_path, dest_subvolume,
 552                           strerror(saved_errno)));
 553                 status = map_nt_error_from_unix(saved_errno);
 554                 closedir(src_dir);
 555                 closedir(dest_dir);
 556                 talloc_free(tmp_ctx);
 557                 return status;
 558         }
 559         DEBUG(5, ("%s -> %s(%s) BTRFS_IOC_SNAP_CREATE_V2 done\n",
 560                   base_volume, dest_path, dest_subvolume));
 561
 562         *_base_path = talloc_steal(mem_ctx, base_path);
 563         *_snap_path = talloc_steal(mem_ctx, snap_path);
 564         closedir(src_dir);
 565         closedir(dest_dir);
 566         talloc_free(tmp_ctx);
 567
 568         return NT_STATUS_OK;
 569 }
 570
 571 static NTSTATUS btrfs_snap_delete(struct vfs_handle_struct *handle,
 572                                   TALLOC_CTX *mem_ctx,
 573                                   char *base_path,
 574                                   char *snap_path)
 575 {
 576         char *tstr;
 577         struct tm t_gmt;
 578         DIR *dest_dir;
 579         int dest_fd;
 580         struct btrfs_ioctl_vol_args ioctl_arg;
 581         int ret;
 582         NTSTATUS status;
 583         char *dest_path;
 584         char *subvolume;
 585         TALLOC_CTX *tmp_ctx;
 586         int saved_errno;
 587         size_t len;
 588
 589         if (!lp_parm_bool(SNUM(handle->conn),
 590                           "btrfs", "manipulate snapshots", false)) {
 591                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 592                 return SMB_VFS_NEXT_SNAP_DELETE(handle, mem_ctx,
 593                                                 base_path, snap_path);
 594         }
 595
 596         tmp_ctx = talloc_new(mem_ctx);
 597         if (tmp_ctx == NULL) {
 598                 return NT_STATUS_NO_MEMORY;
 599         }
 600
 601         dest_path = talloc_strdup(tmp_ctx, snap_path);
 602         if (dest_path == NULL) {
 603                 talloc_free(tmp_ctx);
 604                 return NT_STATUS_NO_MEMORY;
 605         }
 606         subvolume = talloc_strdup(tmp_ctx, snap_path);
 607         if (subvolume == NULL) {
 608                 talloc_free(tmp_ctx);
 609                 return NT_STATUS_NO_MEMORY;
 610         }
 611         dest_path = dirname(dest_path);
 612         subvolume = basename(subvolume);
 613
 614         /* confirm snap_path matches creation format */
 615         tstr = strptime(subvolume, SHADOW_COPY_PATH_FORMAT, &t_gmt);
 616         if ((tstr == NULL) || (*tstr != '\0')) {
 617                 DEBUG(0, ("snapshot path %s does not match creation format\n",
 618                           snap_path));
 619                 talloc_free(tmp_ctx);
 620                 return NT_STATUS_UNSUCCESSFUL;
 621         }
 622
 623         dest_dir = opendir(dest_path);
 624         if (dest_dir == NULL) {
 625                 DEBUG(0, ("snap destroy dest %s open failed: %s\n",
 626                           dest_path, strerror(errno)));
 627                 status = map_nt_error_from_unix(errno);
 628                 talloc_free(tmp_ctx);
 629                 return status;
 630         }
 631         dest_fd = dirfd(dest_dir);
 632         if (dest_fd < 0) {
 633                 status = map_nt_error_from_unix(errno);
 634                 closedir(dest_dir);
 635                 talloc_free(tmp_ctx);
 636                 return status;
 637         }
 638
 639         ioctl_arg.fd = -1;      /* not needed */
 640         len = strlcpy(ioctl_arg.name, subvolume, ARRAY_SIZE(ioctl_arg.name));
 641         if (len >= ARRAY_SIZE(ioctl_arg.name)) {
 642                 DEBUG(1, ("subvolume name too long for SNAP_DESTROY ioctl\n"));
 643                 closedir(dest_dir);
 644                 talloc_free(tmp_ctx);
 645                 return NT_STATUS_INVALID_PARAMETER;
 646         }
 647
 648         become_root();
 649         ret = ioctl(dest_fd, BTRFS_IOC_SNAP_DESTROY, &ioctl_arg);
 650         saved_errno = errno;
 651         unbecome_root();
 652         if (ret < 0) {
 653                 DEBUG(0, ("%s(%s) BTRFS_IOC_SNAP_DESTROY failed: %s\n",
 654                           dest_path, subvolume, strerror(saved_errno)));
 655                 status = map_nt_error_from_unix(saved_errno);
 656                 closedir(dest_dir);
 657                 talloc_free(tmp_ctx);
 658                 return status;
 659         }
 660         DEBUG(5, ("%s(%s) BTRFS_IOC_SNAP_DESTROY done\n",
 661                   dest_path, subvolume));
 662
 663         closedir(dest_dir);
 664         talloc_free(tmp_ctx);
 665         return NT_STATUS_OK;
 666 }
 667
 668 static struct vfs_fn_pointers btrfs_fns = {
 669         .fs_capabilities_fn = btrfs_fs_capabilities,
 670         .copy_chunk_send_fn = btrfs_copy_chunk_send,
 671         .copy_chunk_recv_fn = btrfs_copy_chunk_recv,
 672         .get_compression_fn = btrfs_get_compression,
 673         .set_compression_fn = btrfs_set_compression,
 674         .snap_check_path_fn = btrfs_snap_check_path,
 675         .snap_create_fn = btrfs_snap_create,
 676         .snap_delete_fn = btrfs_snap_delete,
 677 };
 678
 679 NTSTATUS vfs_btrfs_init(void);
 680 NTSTATUS vfs_btrfs_init(void)
 681 {
 682         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 683                                 "btrfs", &btrfs_fns);
 684 }