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 "smbd/globals.h"
  31 #include "librpc/gen_ndr/smbXsrv.h"
  32 #include "librpc/gen_ndr/ioctl.h"
  33 #include "lib/util/tevent_ntstatus.h"
  34 #include "offload_token.h"
  35
  36 static uint32_t btrfs_fs_capabilities(struct vfs_handle_struct *handle,
  37                                       enum timestamp_set_resolution *_ts_res)
  38 {
  39         uint32_t fs_capabilities;
  40         enum timestamp_set_resolution ts_res;
  41
  42         /* inherit default capabilities, expose compression support */
  43         fs_capabilities = SMB_VFS_NEXT_FS_CAPABILITIES(handle, &ts_res);
  44         fs_capabilities |= (FILE_FILE_COMPRESSION
  45                             | FILE_SUPPORTS_BLOCK_REFCOUNTING);
  46         *_ts_res = ts_res;
  47
  48         return fs_capabilities;
  49 }
  50
  51 #define SHADOW_COPY_PREFIX "@GMT-"      /* vfs_shadow_copy format */
  52 #define SHADOW_COPY_PATH_FORMAT "@GMT-%Y.%m.%d-%H.%M.%S"
  53
  54 #define BTRFS_SUBVOL_RDONLY             (1ULL << 1)
  55 #define BTRFS_SUBVOL_NAME_MAX           4039
  56 #define BTRFS_PATH_NAME_MAX             4087
  57 struct btrfs_ioctl_vol_args_v2 {
  58         int64_t fd;
  59         uint64_t transid;
  60         uint64_t flags;
  61         uint64_t unused[4];
  62         char name[BTRFS_SUBVOL_NAME_MAX + 1];
  63 };
  64 struct btrfs_ioctl_vol_args {
  65         int64_t fd;
  66         char name[BTRFS_PATH_NAME_MAX + 1];
  67 };
  68
  69 struct btrfs_ioctl_clone_range_args {
  70         int64_t src_fd;
  71         uint64_t src_offset;
  72         uint64_t src_length;
  73         uint64_t dest_offset;
  74 };
  75
  76 #define BTRFS_IOCTL_MAGIC 0x94
  77 #define BTRFS_IOC_CLONE_RANGE _IOW(BTRFS_IOCTL_MAGIC, 13, \
  78                                    struct btrfs_ioctl_clone_range_args)
  79 #define BTRFS_IOC_SNAP_DESTROY _IOW(BTRFS_IOCTL_MAGIC, 15, \
  80                                     struct btrfs_ioctl_vol_args)
  81 #define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \
  82                                       struct btrfs_ioctl_vol_args_v2)
  83
  84 static struct vfs_offload_ctx *btrfs_offload_ctx;
  85
  86 struct btrfs_offload_read_state {
  87         struct vfs_handle_struct *handle;
  88         files_struct *fsp;
  89         DATA_BLOB token;
  90 };
  91
  92 static void btrfs_offload_read_done(struct tevent_req *subreq);
  93
  94 static struct tevent_req *btrfs_offload_read_send(
  95         TALLOC_CTX *mem_ctx,
  96         struct tevent_context *ev,
  97         struct vfs_handle_struct *handle,
  98         files_struct *fsp,
  99         uint32_t fsctl,
 100         uint32_t ttl,
 101         off_t offset,
 102         size_t to_copy)
 103 {
 104         struct tevent_req *req = NULL;
 105         struct tevent_req *subreq = NULL;
 106         struct btrfs_offload_read_state *state = NULL;
 107         NTSTATUS status;
 108
 109         req = tevent_req_create(mem_ctx, &state,
 110                                 struct btrfs_offload_read_state);
 111         if (req == NULL) {
 112                 return NULL;
 113         }
 114         *state = (struct btrfs_offload_read_state) {
 115                 .handle = handle,
 116                 .fsp = fsp,
 117         };
 118
 119         status = vfs_offload_token_ctx_init(fsp->conn->sconn->client,
 120                                             &btrfs_offload_ctx);
 121         if (tevent_req_nterror(req, status)) {
 122                 return tevent_req_post(req, ev);
 123         }
 124
 125         if (fsctl == FSCTL_DUP_EXTENTS_TO_FILE) {
 126                 status = vfs_offload_token_create_blob(state, fsp, fsctl,
 127                                                        &state->token);
 128                 if (tevent_req_nterror(req, status)) {
 129                         return tevent_req_post(req, ev);
 130                 }
 131
 132                 status = vfs_offload_token_db_store_fsp(btrfs_offload_ctx, fsp,
 133                                                         &state->token);
 134                 if (tevent_req_nterror(req, status)) {
 135                         return tevent_req_post(req, ev);
 136                 }
 137                 tevent_req_done(req);
 138                 return tevent_req_post(req, ev);
 139         }
 140
 141         subreq = SMB_VFS_NEXT_OFFLOAD_READ_SEND(mem_ctx, ev, handle, fsp,
 142                                                 fsctl, ttl, offset, to_copy);
 143         if (tevent_req_nomem(subreq, req)) {
 144                 return tevent_req_post(req, ev);
 145         }
 146         tevent_req_set_callback(subreq, btrfs_offload_read_done, req);
 147         return req;
 148 }
 149
 150 static void btrfs_offload_read_done(struct tevent_req *subreq)
 151 {
 152         struct tevent_req *req = tevent_req_callback_data(
 153                 subreq, struct tevent_req);
 154         struct btrfs_offload_read_state *state = tevent_req_data(
 155                 req, struct btrfs_offload_read_state);
 156         NTSTATUS status;
 157
 158         status = SMB_VFS_NEXT_OFFLOAD_READ_RECV(subreq,
 159                                                 state->handle,
 160                                                 state,
 161                                                 &state->token);
 162         TALLOC_FREE(subreq);
 163         if (tevent_req_nterror(req, status)) {
 164                 return;
 165         }
 166
 167         status = vfs_offload_token_db_store_fsp(btrfs_offload_ctx,
 168                                                 state->fsp,
 169                                                 &state->token);
 170         if (tevent_req_nterror(req, status)) {
 171                 return;
 172         }
 173
 174         tevent_req_done(req);
 175         return;
 176 }
 177
 178 static NTSTATUS btrfs_offload_read_recv(struct tevent_req *req,
 179                                         struct vfs_handle_struct *handle,
 180                                         TALLOC_CTX *mem_ctx,
 181                                         DATA_BLOB *token)
 182 {
 183         struct btrfs_offload_read_state *state = tevent_req_data(
 184                 req, struct btrfs_offload_read_state);
 185         NTSTATUS status;
 186
 187         if (tevent_req_is_nterror(req, &status)) {
 188                 tevent_req_received(req);
 189                 return status;
 190         }
 191
 192         token->length = state->token.length;
 193         token->data = talloc_move(mem_ctx, &state->token.data);
 194
 195         tevent_req_received(req);
 196         return NT_STATUS_OK;
 197 }
 198
 199 struct btrfs_offload_write_state {
 200         struct vfs_handle_struct *handle;
 201         off_t copied;
 202         struct tevent_req *subreq;      /* non-null if passed to next VFS fn */
 203 };
 204 static void btrfs_offload_write_done(struct tevent_req *subreq);
 205
 206 static struct tevent_req *btrfs_offload_write_send(struct vfs_handle_struct *handle,
 207                                                 TALLOC_CTX *mem_ctx,
 208                                                 struct tevent_context *ev,
 209                                                 uint32_t fsctl,
 210                                                 DATA_BLOB *token,
 211                                                 off_t transfer_offset,
 212                                                 struct files_struct *dest_fsp,
 213                                                 off_t dest_off,
 214                                                 off_t num)
 215 {
 216         struct tevent_req *req = NULL;
 217         struct btrfs_offload_write_state *state = NULL;
 218         struct btrfs_ioctl_clone_range_args cr_args;
 219         struct lock_struct src_lck;
 220         struct lock_struct dest_lck;
 221         off_t src_off = transfer_offset;
 222         files_struct *src_fsp = NULL;
 223         int ret;
 224         bool handle_offload_write = true;
 225         bool do_locking = false;
 226         NTSTATUS status;
 227
 228         req = tevent_req_create(mem_ctx, &state,
 229                                 struct btrfs_offload_write_state);
 230         if (req == NULL) {
 231                 return NULL;
 232         }
 233
 234         state->handle = handle;
 235
 236         status = vfs_offload_token_db_fetch_fsp(btrfs_offload_ctx,
 237                                                 token, &src_fsp);
 238         if (tevent_req_nterror(req, status)) {
 239                 return tevent_req_post(req, ev);
 240         }
 241
 242         switch (fsctl) {
 243         case FSCTL_SRV_COPYCHUNK:
 244         case FSCTL_SRV_COPYCHUNK_WRITE:
 245                 do_locking = true;
 246                 break;
 247
 248         case FSCTL_DUP_EXTENTS_TO_FILE:
 249                 /* dup extents does not use locking */
 250                 break;
 251
 252         default:
 253                 handle_offload_write = false;
 254                 break;
 255         }
 256
 257         if (num == 0) {
 258                 /*
 259                  * With a @src_length of zero, BTRFS_IOC_CLONE_RANGE clones
 260                  * all data from @src_offset->EOF! This is certainly not what
 261                  * the caller expects, and not what vfs_default does.
 262                  */
 263                 handle_offload_write = false;
 264         }
 265
 266         if (!handle_offload_write) {
 267                 state->subreq = SMB_VFS_NEXT_OFFLOAD_WRITE_SEND(handle,
 268                                                                 state,
 269                                                                 ev,
 270                                                                 fsctl,
 271                                                                 token,
 272                                                                 transfer_offset,
 273                                                                 dest_fsp,
 274                                                                 dest_off,
 275                                                                 num);
 276                 if (tevent_req_nomem(state->subreq, req)) {
 277                         return tevent_req_post(req, ev);
 278                 }
 279                 tevent_req_set_callback(state->subreq,
 280                                         btrfs_offload_write_done,
 281                                         req);
 282                 return req;
 283         }
 284
 285         status = vfs_offload_token_check_handles(
 286                 fsctl, src_fsp, dest_fsp);
 287         if (!NT_STATUS_IS_OK(status)) {
 288                 tevent_req_nterror(req, status);
 289                 return tevent_req_post(req, ev);
 290         }
 291
 292         status = vfs_stat_fsp(src_fsp);
 293         if (tevent_req_nterror(req, status)) {
 294                 return tevent_req_post(req, ev);
 295         }
 296
 297         if (src_fsp->fsp_name->st.st_ex_size < src_off + num) {
 298                 /* [MS-SMB2] Handling a Server-Side Data Copy Request */
 299                 tevent_req_nterror(req, NT_STATUS_INVALID_VIEW_SIZE);
 300                 return tevent_req_post(req, ev);
 301         }
 302
 303         if (do_locking) {
 304                 init_strict_lock_struct(src_fsp,
 305                                         src_fsp->op->global->open_persistent_id,
 306                                         src_off,
 307                                         num,
 308                                         READ_LOCK,
 309                                         &src_lck);
 310                 init_strict_lock_struct(dest_fsp,
 311                                        dest_fsp->op->global->open_persistent_id,
 312                                         dest_off,
 313                                         num,
 314                                         WRITE_LOCK,
 315                                         &dest_lck);
 316
 317                 if (!SMB_VFS_STRICT_LOCK_CHECK(src_fsp->conn, src_fsp, &src_lck)) {
 318                         tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 319                         return tevent_req_post(req, ev);
 320                 }
 321                 if (!SMB_VFS_STRICT_LOCK_CHECK(dest_fsp->conn, dest_fsp, &dest_lck)) {
 322                         tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 323                         return tevent_req_post(req, ev);
 324                 }
 325         }
 326
 327         ZERO_STRUCT(cr_args);
 328         cr_args.src_fd = src_fsp->fh->fd;
 329         cr_args.src_offset = (uint64_t)src_off;
 330         cr_args.dest_offset = (uint64_t)dest_off;
 331         cr_args.src_length = (uint64_t)num;
 332
 333         ret = ioctl(dest_fsp->fh->fd, BTRFS_IOC_CLONE_RANGE, &cr_args);
 334         if (ret < 0) {
 335                 /*
 336                  * BTRFS_IOC_CLONE_RANGE only supports 'sectorsize' aligned
 337                  * cloning. Which is 4096 by default, therefore fall back to
 338                  * manual read/write on failure.
 339                  */
 340                 DEBUG(5, ("BTRFS_IOC_CLONE_RANGE failed: %s, length %llu, "
 341                           "src fd: %lld off: %llu, dest fd: %d off: %llu\n",
 342                           strerror(errno),
 343                           (unsigned long long)cr_args.src_length,
 344                           (long long)cr_args.src_fd,
 345                           (unsigned long long)cr_args.src_offset,
 346                           dest_fsp->fh->fd,
 347                           (unsigned long long)cr_args.dest_offset));
 348                 state->subreq = SMB_VFS_NEXT_OFFLOAD_WRITE_SEND(handle,
 349                                                                 state,
 350                                                                 ev,
 351                                                                 fsctl,
 352                                                                 token,
 353                                                                 transfer_offset,
 354                                                                 dest_fsp,
 355                                                                 dest_off,
 356                                                                 num);
 357                 if (tevent_req_nomem(state->subreq, req)) {
 358                         return tevent_req_post(req, ev);
 359                 }
 360                 /* wait for subreq completion */
 361                 tevent_req_set_callback(state->subreq,
 362                                         btrfs_offload_write_done,
 363                                         req);
 364                 return req;
 365         }
 366
 367         DEBUG(5, ("BTRFS_IOC_CLONE_RANGE returned %d\n", ret));
 368         /* BTRFS_IOC_CLONE_RANGE is all or nothing */
 369         state->copied = num;
 370         tevent_req_done(req);
 371         return tevent_req_post(req, ev);
 372 }
 373
 374 /* only used if the request is passed through to next VFS module */
 375 static void btrfs_offload_write_done(struct tevent_req *subreq)
 376 {
 377         struct tevent_req *req =
 378                 tevent_req_callback_data(subreq,
 379                 struct tevent_req);
 380         struct btrfs_offload_write_state *state =
 381                 tevent_req_data(req,
 382                 struct btrfs_offload_write_state);
 383         NTSTATUS status;
 384
 385         status = SMB_VFS_NEXT_OFFLOAD_WRITE_RECV(state->handle,
 386                                                  state->subreq,
 387                                                  &state->copied);
 388         if (tevent_req_nterror(req, status)) {
 389                 return;
 390         }
 391         tevent_req_done(req);
 392 }
 393
 394 static NTSTATUS btrfs_offload_write_recv(struct vfs_handle_struct *handle,
 395                                          struct tevent_req *req,
 396                                          off_t *copied)
 397 {
 398         struct btrfs_offload_write_state *state =
 399                 tevent_req_data(req,
 400                 struct btrfs_offload_write_state);
 401         NTSTATUS status;
 402
 403         if (tevent_req_is_nterror(req, &status)) {
 404                 DEBUG(4, ("server side copy chunk failed: %s\n",
 405                           nt_errstr(status)));
 406                 tevent_req_received(req);
 407                 return status;
 408         }
 409
 410         DEBUG(10, ("server side copy chunk copied %llu\n",
 411                    (unsigned long long)state->copied));
 412         *copied = state->copied;
 413         tevent_req_received(req);
 414         return NT_STATUS_OK;
 415 }
 416
 417 /*
 418  * caller must pass a non-null fsp or smb_fname. If fsp is null, then
 419  * fall back to opening the corresponding file to issue the ioctl.
 420  */
 421 static NTSTATUS btrfs_get_compression(struct vfs_handle_struct *handle,
 422                                       TALLOC_CTX *mem_ctx,
 423                                       struct files_struct *fsp,
 424                                       struct smb_filename *smb_fname,
 425                                       uint16_t *_compression_fmt)
 426 {
 427         int ret;
 428         long flags = 0;
 429         int fd;
 430         bool opened = false;
 431         NTSTATUS status;
 432         DIR *dir = NULL;
 433
 434         if ((fsp != NULL) && (fsp->fh->fd != -1)) {
 435                 fd = fsp->fh->fd;
 436         } else if (smb_fname != NULL) {
 437                 if (S_ISDIR(smb_fname->st.st_ex_mode)) {
 438                         dir = opendir(smb_fname->base_name);
 439                         if (dir == NULL) {
 440                                 return NT_STATUS_UNSUCCESSFUL;
 441                         }
 442                         opened = true;
 443                         fd = dirfd(dir);
 444                         if (fd < 0) {
 445                                 status = NT_STATUS_UNSUCCESSFUL;
 446                                 goto err_close;
 447                         }
 448                 } else {
 449                         fd = open(smb_fname->base_name, O_RDONLY);
 450                         if (fd < 0) {
 451                                 return NT_STATUS_UNSUCCESSFUL;
 452                         }
 453                         opened = true;
 454                 }
 455         } else {
 456                 return NT_STATUS_INVALID_PARAMETER;
 457         }
 458
 459         ret = ioctl(fd, FS_IOC_GETFLAGS, &flags);
 460         if (ret < 0) {
 461                 DEBUG(1, ("FS_IOC_GETFLAGS failed: %s, fd %lld\n",
 462                           strerror(errno), (long long)fd));
 463                 status = map_nt_error_from_unix(errno);
 464                 goto err_close;
 465         }
 466         if (flags & FS_COMPR_FL) {
 467                 *_compression_fmt = COMPRESSION_FORMAT_LZNT1;
 468         } else {
 469                 *_compression_fmt = COMPRESSION_FORMAT_NONE;
 470         }
 471         status = NT_STATUS_OK;
 472 err_close:
 473         if (opened) {
 474                 if (dir != NULL) {
 475                         closedir(dir);
 476                 } else {
 477                         close(fd);
 478                 }
 479         }
 480
 481         return status;
 482 }
 483
 484 static NTSTATUS btrfs_set_compression(struct vfs_handle_struct *handle,
 485                                       TALLOC_CTX *mem_ctx,
 486                                       struct files_struct *fsp,
 487                                       uint16_t compression_fmt)
 488 {
 489         int ret;
 490         long flags = 0;
 491         int fd;
 492         NTSTATUS status;
 493
 494         if ((fsp == NULL) || (fsp->fh->fd == -1)) {
 495                 status = NT_STATUS_INVALID_PARAMETER;
 496                 goto err_out;
 497         }
 498         fd = fsp->fh->fd;
 499
 500         ret = ioctl(fd, FS_IOC_GETFLAGS, &flags);
 501         if (ret < 0) {
 502                 DEBUG(1, ("FS_IOC_GETFLAGS failed: %s, fd %d\n",
 503                           strerror(errno), fd));
 504                 status = map_nt_error_from_unix(errno);
 505                 goto err_out;
 506         }
 507
 508         if (compression_fmt == COMPRESSION_FORMAT_NONE) {
 509                 DEBUG(5, ("setting compression\n"));
 510                 flags &= (~FS_COMPR_FL);
 511         } else if ((compression_fmt == COMPRESSION_FORMAT_DEFAULT)
 512                 || (compression_fmt == COMPRESSION_FORMAT_LZNT1)) {
 513                 DEBUG(5, ("clearing compression\n"));
 514                 flags |= FS_COMPR_FL;
 515         } else {
 516                 DEBUG(1, ("invalid compression format 0x%x\n",
 517                           (int)compression_fmt));
 518                 status = NT_STATUS_INVALID_PARAMETER;
 519                 goto err_out;
 520         }
 521
 522         ret = ioctl(fd, FS_IOC_SETFLAGS, &flags);
 523         if (ret < 0) {
 524                 DEBUG(1, ("FS_IOC_SETFLAGS failed: %s, fd %d\n",
 525                           strerror(errno), fd));
 526                 status = map_nt_error_from_unix(errno);
 527                 goto err_out;
 528         }
 529         status = NT_STATUS_OK;
 530 err_out:
 531         return status;
 532 }
 533
 534 /*
 535  * Check whether a path can be shadow copied. Return the base volume, allowing
 536  * the caller to determine if multiple paths lie on the same base volume.
 537  */
 538 #define BTRFS_INODE_SUBVOL 256
 539 static NTSTATUS btrfs_snap_check_path(struct vfs_handle_struct *handle,
 540                                       TALLOC_CTX *mem_ctx,
 541                                       const char *service_path,
 542                                       char **base_volume)
 543 {
 544         struct stat st;
 545         char *base;
 546
 547         if (!lp_parm_bool(SNUM(handle->conn),
 548                          "btrfs", "manipulate snapshots", false)) {
 549                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 550                 return SMB_VFS_NEXT_SNAP_CHECK_PATH(handle, mem_ctx,
 551                                                     service_path, base_volume);
 552         }
 553
 554         /* btrfs userspace uses this logic to confirm subvolume */
 555         if (stat(service_path, &st) < 0) {
 556                 return NT_STATUS_NOT_SUPPORTED;
 557         }
 558         if ((st.st_ino != BTRFS_INODE_SUBVOL) || !S_ISDIR(st.st_mode)) {
 559                 DEBUG(0, ("%s not a btrfs subvolume, snapshots not available\n",
 560                           service_path));
 561                 return NT_STATUS_NOT_SUPPORTED;
 562         }
 563
 564         /* we "snapshot" the service path itself */
 565         base = talloc_strdup(mem_ctx, service_path);
 566         if (base == NULL) {
 567                 return NT_STATUS_NO_MEMORY;
 568         }
 569         *base_volume = base;
 570
 571         return NT_STATUS_OK;
 572 }
 573
 574 static NTSTATUS btrfs_gen_snap_dest_path(TALLOC_CTX *mem_ctx,
 575                                          const char *src_path,
 576                                          time_t *tstamp,
 577                                          char **dest_path, char **subvolume)
 578 {
 579         struct tm t_gmt;
 580         char time_str[50];
 581         size_t tlen;
 582
 583         gmtime_r(tstamp, &t_gmt);
 584
 585         tlen = strftime(time_str, ARRAY_SIZE(time_str),
 586                         SHADOW_COPY_PATH_FORMAT, &t_gmt);
 587         if (tlen <= 0) {
 588                 return NT_STATUS_UNSUCCESSFUL;
 589         }
 590
 591         *dest_path = talloc_strdup(mem_ctx, src_path);
 592         *subvolume = talloc_strdup(mem_ctx, time_str);
 593         if ((*dest_path == NULL) || (*subvolume == NULL)) {
 594                 return NT_STATUS_NO_MEMORY;
 595         }
 596
 597         return NT_STATUS_OK;
 598 }
 599
 600 static NTSTATUS btrfs_snap_create(struct vfs_handle_struct *handle,
 601                                   TALLOC_CTX *mem_ctx,
 602                                   const char *base_volume,
 603                                   time_t *tstamp,
 604                                   bool rw,
 605                                   char **_base_path,
 606                                   char **_snap_path)
 607 {
 608         struct btrfs_ioctl_vol_args_v2 ioctl_arg;
 609         DIR *src_dir;
 610         DIR *dest_dir;
 611         int src_fd;
 612         int dest_fd;
 613         char *dest_path = NULL;
 614         char *dest_subvolume = NULL;
 615         int ret;
 616         NTSTATUS status;
 617         char *base_path;
 618         char *snap_path;
 619         TALLOC_CTX *tmp_ctx;
 620         int saved_errno;
 621         size_t len;
 622
 623         if (!lp_parm_bool(SNUM(handle->conn),
 624                           "btrfs", "manipulate snapshots", false)) {
 625                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 626                 return SMB_VFS_NEXT_SNAP_CREATE(handle, mem_ctx, base_volume,
 627                                                 tstamp, rw, _base_path,
 628                                                 _snap_path);
 629         }
 630
 631         tmp_ctx = talloc_new(mem_ctx);
 632         if (tmp_ctx == NULL) {
 633                 return NT_STATUS_NO_MEMORY;
 634         }
 635
 636         base_path = talloc_strdup(tmp_ctx, base_volume);
 637         if (base_path == NULL) {
 638                 talloc_free(tmp_ctx);
 639                 return NT_STATUS_NO_MEMORY;
 640         }
 641
 642         status = btrfs_gen_snap_dest_path(tmp_ctx, base_volume, tstamp,
 643                                           &dest_path, &dest_subvolume);
 644         if (!NT_STATUS_IS_OK(status)) {
 645                 talloc_free(tmp_ctx);
 646                 return status;
 647         }
 648
 649         snap_path = talloc_asprintf(tmp_ctx, "%s/%s", dest_path,
 650                                     dest_subvolume);
 651         if (snap_path == NULL) {
 652                 talloc_free(tmp_ctx);
 653                 return NT_STATUS_NO_MEMORY;
 654         }
 655
 656         src_dir = opendir(base_volume);
 657         if (src_dir == NULL) {
 658                 DEBUG(0, ("snap src %s open failed: %s\n",
 659                           base_volume, strerror(errno)));
 660                 status = map_nt_error_from_unix(errno);
 661                 talloc_free(tmp_ctx);
 662                 return status;
 663         }
 664         src_fd = dirfd(src_dir);
 665         if (src_fd < 0) {
 666                 status = map_nt_error_from_unix(errno);
 667                 closedir(src_dir);
 668                 talloc_free(tmp_ctx);
 669                 return status;
 670         }
 671
 672         dest_dir = opendir(dest_path);
 673         if (dest_dir == NULL) {
 674                 DEBUG(0, ("snap dest %s open failed: %s\n",
 675                           dest_path, strerror(errno)));
 676                 status = map_nt_error_from_unix(errno);
 677                 closedir(src_dir);
 678                 talloc_free(tmp_ctx);
 679                 return status;
 680         }
 681         dest_fd = dirfd(dest_dir);
 682         if (dest_fd < 0) {
 683                 status = map_nt_error_from_unix(errno);
 684                 closedir(src_dir);
 685                 closedir(dest_dir);
 686                 talloc_free(tmp_ctx);
 687                 return status;
 688         }
 689
 690         /* avoid zeroing the entire struct here, name is 4k */
 691         ioctl_arg.fd = src_fd;
 692         ioctl_arg.transid = 0;
 693         ioctl_arg.flags = (rw == false) ? BTRFS_SUBVOL_RDONLY : 0;
 694         memset(ioctl_arg.unused, 0, sizeof(ioctl_arg.unused));
 695         len = strlcpy(ioctl_arg.name, dest_subvolume,
 696                       ARRAY_SIZE(ioctl_arg.name));
 697         if (len >= ARRAY_SIZE(ioctl_arg.name)) {
 698                 DEBUG(1, ("subvolume name too long for SNAP_CREATE ioctl\n"));
 699                 closedir(src_dir);
 700                 closedir(dest_dir);
 701                 talloc_free(tmp_ctx);
 702                 return NT_STATUS_INVALID_PARAMETER;
 703         }
 704
 705         become_root();
 706         ret = ioctl(dest_fd, BTRFS_IOC_SNAP_CREATE_V2, &ioctl_arg);
 707         saved_errno = errno;
 708         unbecome_root();
 709         if (ret < 0) {
 710                 DEBUG(0, ("%s -> %s(%s) BTRFS_IOC_SNAP_CREATE_V2 failed: %s\n",
 711                           base_volume, dest_path, dest_subvolume,
 712                           strerror(saved_errno)));
 713                 status = map_nt_error_from_unix(saved_errno);
 714                 closedir(src_dir);
 715                 closedir(dest_dir);
 716                 talloc_free(tmp_ctx);
 717                 return status;
 718         }
 719         DEBUG(5, ("%s -> %s(%s) BTRFS_IOC_SNAP_CREATE_V2 done\n",
 720                   base_volume, dest_path, dest_subvolume));
 721
 722         *_base_path = talloc_steal(mem_ctx, base_path);
 723         *_snap_path = talloc_steal(mem_ctx, snap_path);
 724         closedir(src_dir);
 725         closedir(dest_dir);
 726         talloc_free(tmp_ctx);
 727
 728         return NT_STATUS_OK;
 729 }
 730
 731 static NTSTATUS btrfs_snap_delete(struct vfs_handle_struct *handle,
 732                                   TALLOC_CTX *mem_ctx,
 733                                   char *base_path,
 734                                   char *snap_path)
 735 {
 736         char *tstr;
 737         struct tm t_gmt;
 738         DIR *dest_dir;
 739         int dest_fd;
 740         struct btrfs_ioctl_vol_args ioctl_arg;
 741         int ret;
 742         NTSTATUS status;
 743         char *dest_path;
 744         char *subvolume;
 745         TALLOC_CTX *tmp_ctx;
 746         int saved_errno;
 747         size_t len;
 748
 749         if (!lp_parm_bool(SNUM(handle->conn),
 750                           "btrfs", "manipulate snapshots", false)) {
 751                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 752                 return SMB_VFS_NEXT_SNAP_DELETE(handle, mem_ctx,
 753                                                 base_path, snap_path);
 754         }
 755
 756         tmp_ctx = talloc_new(mem_ctx);
 757         if (tmp_ctx == NULL) {
 758                 return NT_STATUS_NO_MEMORY;
 759         }
 760
 761         dest_path = talloc_strdup(tmp_ctx, snap_path);
 762         if (dest_path == NULL) {
 763                 talloc_free(tmp_ctx);
 764                 return NT_STATUS_NO_MEMORY;
 765         }
 766         subvolume = talloc_strdup(tmp_ctx, snap_path);
 767         if (subvolume == NULL) {
 768                 talloc_free(tmp_ctx);
 769                 return NT_STATUS_NO_MEMORY;
 770         }
 771         dest_path = dirname(dest_path);
 772         subvolume = basename(subvolume);
 773
 774         /* confirm snap_path matches creation format */
 775         tstr = strptime(subvolume, SHADOW_COPY_PATH_FORMAT, &t_gmt);
 776         if ((tstr == NULL) || (*tstr != '\0')) {
 777                 DEBUG(0, ("snapshot path %s does not match creation format\n",
 778                           snap_path));
 779                 talloc_free(tmp_ctx);
 780                 return NT_STATUS_UNSUCCESSFUL;
 781         }
 782
 783         dest_dir = opendir(dest_path);
 784         if (dest_dir == NULL) {
 785                 DEBUG(0, ("snap destroy dest %s open failed: %s\n",
 786                           dest_path, strerror(errno)));
 787                 status = map_nt_error_from_unix(errno);
 788                 talloc_free(tmp_ctx);
 789                 return status;
 790         }
 791         dest_fd = dirfd(dest_dir);
 792         if (dest_fd < 0) {
 793                 status = map_nt_error_from_unix(errno);
 794                 closedir(dest_dir);
 795                 talloc_free(tmp_ctx);
 796                 return status;
 797         }
 798
 799         ioctl_arg.fd = -1;      /* not needed */
 800         len = strlcpy(ioctl_arg.name, subvolume, ARRAY_SIZE(ioctl_arg.name));
 801         if (len >= ARRAY_SIZE(ioctl_arg.name)) {
 802                 DEBUG(1, ("subvolume name too long for SNAP_DESTROY ioctl\n"));
 803                 closedir(dest_dir);
 804                 talloc_free(tmp_ctx);
 805                 return NT_STATUS_INVALID_PARAMETER;
 806         }
 807
 808         become_root();
 809         ret = ioctl(dest_fd, BTRFS_IOC_SNAP_DESTROY, &ioctl_arg);
 810         saved_errno = errno;
 811         unbecome_root();
 812         if (ret < 0) {
 813                 DEBUG(0, ("%s(%s) BTRFS_IOC_SNAP_DESTROY failed: %s\n",
 814                           dest_path, subvolume, strerror(saved_errno)));
 815                 status = map_nt_error_from_unix(saved_errno);
 816                 closedir(dest_dir);
 817                 talloc_free(tmp_ctx);
 818                 return status;
 819         }
 820         DEBUG(5, ("%s(%s) BTRFS_IOC_SNAP_DESTROY done\n",
 821                   dest_path, subvolume));
 822
 823         closedir(dest_dir);
 824         talloc_free(tmp_ctx);
 825         return NT_STATUS_OK;
 826 }
 827
 828 static struct vfs_fn_pointers btrfs_fns = {
 829         .fs_capabilities_fn = btrfs_fs_capabilities,
 830         .offload_read_send_fn = btrfs_offload_read_send,
 831         .offload_read_recv_fn = btrfs_offload_read_recv,
 832         .offload_write_send_fn = btrfs_offload_write_send,
 833         .offload_write_recv_fn = btrfs_offload_write_recv,
 834         .get_compression_fn = btrfs_get_compression,
 835         .set_compression_fn = btrfs_set_compression,
 836         .snap_check_path_fn = btrfs_snap_check_path,
 837         .snap_create_fn = btrfs_snap_create,
 838         .snap_delete_fn = btrfs_snap_delete,
 839 };
 840
 841 static_decl_vfs;
 842 NTSTATUS vfs_btrfs_init(TALLOC_CTX *ctx)
 843 {
 844         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 845                                 "btrfs", &btrfs_fns);
 846 }