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 "includes.h"
  21 #include "system/filesys.h"
  22 #include <linux/ioctl.h>
  23 #include <linux/fs.h>
  24 #include <sys/ioctl.h>
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27 #include <dirent.h>
  28 #include <libgen.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         uint32_t flags;
  90         uint64_t xferlen;
  91         DATA_BLOB token;
  92 };
  93
  94 static void btrfs_offload_read_done(struct tevent_req *subreq);
  95
  96 static struct tevent_req *btrfs_offload_read_send(
  97         TALLOC_CTX *mem_ctx,
  98         struct tevent_context *ev,
  99         struct vfs_handle_struct *handle,
 100         files_struct *fsp,
 101         uint32_t fsctl,
 102         uint32_t ttl,
 103         off_t offset,
 104         size_t to_copy)
 105 {
 106         struct tevent_req *req = NULL;
 107         struct tevent_req *subreq = NULL;
 108         struct btrfs_offload_read_state *state = NULL;
 109         NTSTATUS status;
 110
 111         req = tevent_req_create(mem_ctx, &state,
 112                                 struct btrfs_offload_read_state);
 113         if (req == NULL) {
 114                 return NULL;
 115         }
 116         *state = (struct btrfs_offload_read_state) {
 117                 .handle = handle,
 118                 .fsp = fsp,
 119         };
 120
 121         status = vfs_offload_token_ctx_init(fsp->conn->sconn->client,
 122                                             &btrfs_offload_ctx);
 123         if (tevent_req_nterror(req, status)) {
 124                 return tevent_req_post(req, ev);
 125         }
 126
 127         if (fsctl == FSCTL_DUP_EXTENTS_TO_FILE) {
 128                 status = vfs_offload_token_create_blob(state, fsp, fsctl,
 129                                                        &state->token);
 130                 if (tevent_req_nterror(req, status)) {
 131                         return tevent_req_post(req, ev);
 132                 }
 133
 134                 status = vfs_offload_token_db_store_fsp(btrfs_offload_ctx, fsp,
 135                                                         &state->token);
 136                 if (tevent_req_nterror(req, status)) {
 137                         return tevent_req_post(req, ev);
 138                 }
 139                 tevent_req_done(req);
 140                 return tevent_req_post(req, ev);
 141         }
 142
 143         subreq = SMB_VFS_NEXT_OFFLOAD_READ_SEND(mem_ctx, ev, handle, fsp,
 144                                                 fsctl, ttl, offset, to_copy);
 145         if (tevent_req_nomem(subreq, req)) {
 146                 return tevent_req_post(req, ev);
 147         }
 148         tevent_req_set_callback(subreq, btrfs_offload_read_done, req);
 149         return req;
 150 }
 151
 152 static void btrfs_offload_read_done(struct tevent_req *subreq)
 153 {
 154         struct tevent_req *req = tevent_req_callback_data(
 155                 subreq, struct tevent_req);
 156         struct btrfs_offload_read_state *state = tevent_req_data(
 157                 req, struct btrfs_offload_read_state);
 158         NTSTATUS status;
 159
 160         status = SMB_VFS_NEXT_OFFLOAD_READ_RECV(subreq,
 161                                                 state->handle,
 162                                                 state,
 163                                                 &state->flags,
 164                                                 &state->xferlen,
 165                                                 &state->token);
 166         TALLOC_FREE(subreq);
 167         if (tevent_req_nterror(req, status)) {
 168                 return;
 169         }
 170
 171         status = vfs_offload_token_db_store_fsp(btrfs_offload_ctx,
 172                                                 state->fsp,
 173                                                 &state->token);
 174         if (tevent_req_nterror(req, status)) {
 175                 return;
 176         }
 177
 178         tevent_req_done(req);
 179         return;
 180 }
 181
 182 static NTSTATUS btrfs_offload_read_recv(struct tevent_req *req,
 183                                         struct vfs_handle_struct *handle,
 184                                         TALLOC_CTX *mem_ctx,
 185                                         uint32_t *flags,
 186                                         uint64_t *xferlen,
 187                                         DATA_BLOB *token)
 188 {
 189         struct btrfs_offload_read_state *state = tevent_req_data(
 190                 req, struct btrfs_offload_read_state);
 191         NTSTATUS status;
 192
 193         if (tevent_req_is_nterror(req, &status)) {
 194                 tevent_req_received(req);
 195                 return status;
 196         }
 197
 198         *flags = state->flags;
 199         *xferlen = state->xferlen;
 200         token->length = state->token.length;
 201         token->data = talloc_move(mem_ctx, &state->token.data);
 202
 203         tevent_req_received(req);
 204         return NT_STATUS_OK;
 205 }
 206
 207 struct btrfs_offload_write_state {
 208         struct vfs_handle_struct *handle;
 209         off_t copied;
 210         bool need_unbecome_user;
 211 };
 212
 213 static void btrfs_offload_write_cleanup(struct tevent_req *req,
 214                                         enum tevent_req_state req_state)
 215 {
 216         struct btrfs_offload_write_state *state =
 217                 tevent_req_data(req,
 218                 struct btrfs_offload_write_state);
 219         bool ok;
 220
 221         if (!state->need_unbecome_user) {
 222                 return;
 223         }
 224
 225         ok = unbecome_user_without_service();
 226         SMB_ASSERT(ok);
 227         state->need_unbecome_user = false;
 228 }
 229
 230 static void btrfs_offload_write_done(struct tevent_req *subreq);
 231
 232 static struct tevent_req *btrfs_offload_write_send(struct vfs_handle_struct *handle,
 233                                                 TALLOC_CTX *mem_ctx,
 234                                                 struct tevent_context *ev,
 235                                                 uint32_t fsctl,
 236                                                 DATA_BLOB *token,
 237                                                 off_t transfer_offset,
 238                                                 struct files_struct *dest_fsp,
 239                                                 off_t dest_off,
 240                                                 off_t num)
 241 {
 242         struct tevent_req *req = NULL;
 243         struct btrfs_offload_write_state *state = NULL;
 244         struct tevent_req *subreq = NULL;
 245         struct btrfs_ioctl_clone_range_args cr_args;
 246         struct lock_struct src_lck;
 247         struct lock_struct dest_lck;
 248         off_t src_off = transfer_offset;
 249         files_struct *src_fsp = NULL;
 250         int ret;
 251         bool handle_offload_write = true;
 252         bool do_locking = false;
 253         NTSTATUS status;
 254         bool ok;
 255
 256         req = tevent_req_create(mem_ctx, &state,
 257                                 struct btrfs_offload_write_state);
 258         if (req == NULL) {
 259                 return NULL;
 260         }
 261
 262         state->handle = handle;
 263
 264         tevent_req_set_cleanup_fn(req, btrfs_offload_write_cleanup);
 265
 266         status = vfs_offload_token_db_fetch_fsp(btrfs_offload_ctx,
 267                                                 token, &src_fsp);
 268         if (tevent_req_nterror(req, status)) {
 269                 return tevent_req_post(req, ev);
 270         }
 271
 272         switch (fsctl) {
 273         case FSCTL_SRV_COPYCHUNK:
 274         case FSCTL_SRV_COPYCHUNK_WRITE:
 275                 do_locking = true;
 276                 break;
 277
 278         case FSCTL_DUP_EXTENTS_TO_FILE:
 279                 /* dup extents does not use locking */
 280                 break;
 281
 282         default:
 283                 handle_offload_write = false;
 284                 break;
 285         }
 286
 287         if (num == 0) {
 288                 /*
 289                  * With a @src_length of zero, BTRFS_IOC_CLONE_RANGE clones
 290                  * all data from @src_offset->EOF! This is certainly not what
 291                  * the caller expects, and not what vfs_default does.
 292                  */
 293                 handle_offload_write = false;
 294         }
 295
 296         if (!handle_offload_write) {
 297                 subreq = SMB_VFS_NEXT_OFFLOAD_WRITE_SEND(handle,
 298                                                          state,
 299                                                          ev,
 300                                                          fsctl,
 301                                                          token,
 302                                                          transfer_offset,
 303                                                          dest_fsp,
 304                                                          dest_off,
 305                                                          num);
 306                 if (tevent_req_nomem(subreq, req)) {
 307                         return tevent_req_post(req, ev);
 308                 }
 309                 tevent_req_set_callback(subreq,
 310                                         btrfs_offload_write_done,
 311                                         req);
 312                 return req;
 313         }
 314
 315         status = vfs_offload_token_check_handles(
 316                 fsctl, src_fsp, dest_fsp);
 317         if (!NT_STATUS_IS_OK(status)) {
 318                 tevent_req_nterror(req, status);
 319                 return tevent_req_post(req, ev);
 320         }
 321
 322         ok = become_user_without_service_by_fsp(src_fsp);
 323         if (!ok) {
 324                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 325                 return tevent_req_post(req, ev);
 326         }
 327         state->need_unbecome_user = true;
 328
 329         status = vfs_stat_fsp(src_fsp);
 330         if (tevent_req_nterror(req, status)) {
 331                 return tevent_req_post(req, ev);
 332         }
 333
 334         if (src_fsp->fsp_name->st.st_ex_size < src_off + num) {
 335                 /* [MS-SMB2] Handling a Server-Side Data Copy Request */
 336                 tevent_req_nterror(req, NT_STATUS_INVALID_VIEW_SIZE);
 337                 return tevent_req_post(req, ev);
 338         }
 339
 340         if (do_locking) {
 341                 init_strict_lock_struct(src_fsp,
 342                                         src_fsp->op->global->open_persistent_id,
 343                                         src_off,
 344                                         num,
 345                                         READ_LOCK,
 346                                         lp_posix_cifsu_locktype(src_fsp),
 347                                         &src_lck);
 348                 if (!SMB_VFS_STRICT_LOCK_CHECK(src_fsp->conn, src_fsp, &src_lck)) {
 349                         tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 350                         return tevent_req_post(req, ev);
 351                 }
 352         }
 353
 354         ok = unbecome_user_without_service();
 355         SMB_ASSERT(ok);
 356         state->need_unbecome_user = false;
 357
 358         if (do_locking) {
 359                 init_strict_lock_struct(dest_fsp,
 360                                         dest_fsp->op->global->open_persistent_id,
 361                                         dest_off,
 362                                         num,
 363                                         WRITE_LOCK,
 364                                         lp_posix_cifsu_locktype(dest_fsp),
 365                                         &dest_lck);
 366
 367                 if (!SMB_VFS_STRICT_LOCK_CHECK(dest_fsp->conn, dest_fsp, &dest_lck)) {
 368                         tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 369                         return tevent_req_post(req, ev);
 370                 }
 371         }
 372
 373         ZERO_STRUCT(cr_args);
 374         cr_args.src_fd = fsp_get_io_fd(src_fsp);
 375         cr_args.src_offset = (uint64_t)src_off;
 376         cr_args.dest_offset = (uint64_t)dest_off;
 377         cr_args.src_length = (uint64_t)num;
 378
 379         ret = ioctl(fsp_get_io_fd(dest_fsp), BTRFS_IOC_CLONE_RANGE, &cr_args);
 380         if (ret < 0) {
 381                 /*
 382                  * BTRFS_IOC_CLONE_RANGE only supports 'sectorsize' aligned
 383                  * cloning. Which is 4096 by default, therefore fall back to
 384                  * manual read/write on failure.
 385                  */
 386                 DEBUG(5, ("BTRFS_IOC_CLONE_RANGE failed: %s, length %llu, "
 387                           "src fd: %lld off: %llu, dest fd: %d off: %llu\n",
 388                           strerror(errno),
 389                           (unsigned long long)cr_args.src_length,
 390                           (long long)cr_args.src_fd,
 391                           (unsigned long long)cr_args.src_offset,
 392                           fsp_get_io_fd(dest_fsp),
 393                           (unsigned long long)cr_args.dest_offset));
 394                 subreq = SMB_VFS_NEXT_OFFLOAD_WRITE_SEND(handle,
 395                                                          state,
 396                                                          ev,
 397                                                          fsctl,
 398                                                          token,
 399                                                          transfer_offset,
 400                                                          dest_fsp,
 401                                                          dest_off,
 402                                                          num);
 403                 if (tevent_req_nomem(subreq, req)) {
 404                         return tevent_req_post(req, ev);
 405                 }
 406                 /* wait for subreq completion */
 407                 tevent_req_set_callback(subreq,
 408                                         btrfs_offload_write_done,
 409                                         req);
 410                 return req;
 411         }
 412
 413         DEBUG(5, ("BTRFS_IOC_CLONE_RANGE returned %d\n", ret));
 414         /* BTRFS_IOC_CLONE_RANGE is all or nothing */
 415         state->copied = num;
 416         tevent_req_done(req);
 417         return tevent_req_post(req, ev);
 418 }
 419
 420 /* only used if the request is passed through to next VFS module */
 421 static void btrfs_offload_write_done(struct tevent_req *subreq)
 422 {
 423         struct tevent_req *req =
 424                 tevent_req_callback_data(subreq,
 425                 struct tevent_req);
 426         struct btrfs_offload_write_state *state =
 427                 tevent_req_data(req,
 428                 struct btrfs_offload_write_state);
 429         NTSTATUS status;
 430
 431         status = SMB_VFS_NEXT_OFFLOAD_WRITE_RECV(state->handle,
 432                                                  subreq,
 433                                                  &state->copied);
 434         TALLOC_FREE(subreq);
 435         if (tevent_req_nterror(req, status)) {
 436                 return;
 437         }
 438         tevent_req_done(req);
 439 }
 440
 441 static NTSTATUS btrfs_offload_write_recv(struct vfs_handle_struct *handle,
 442                                          struct tevent_req *req,
 443                                          off_t *copied)
 444 {
 445         struct btrfs_offload_write_state *state =
 446                 tevent_req_data(req,
 447                 struct btrfs_offload_write_state);
 448         NTSTATUS status;
 449
 450         if (tevent_req_is_nterror(req, &status)) {
 451                 DEBUG(4, ("server side copy chunk failed: %s\n",
 452                           nt_errstr(status)));
 453                 tevent_req_received(req);
 454                 return status;
 455         }
 456
 457         DEBUG(10, ("server side copy chunk copied %llu\n",
 458                    (unsigned long long)state->copied));
 459         *copied = state->copied;
 460         tevent_req_received(req);
 461         return NT_STATUS_OK;
 462 }
 463
 464 static NTSTATUS btrfs_fget_compression(struct vfs_handle_struct *handle,
 465                                        TALLOC_CTX *mem_ctx,
 466                                        struct files_struct *fsp,
 467                                        uint16_t *_compression_fmt)
 468 {
 469         struct sys_proc_fd_path_buf buf;
 470         int ret;
 471         long flags = 0;
 472         int fsp_fd = fsp_get_pathref_fd(fsp);
 473         int fd = -1;
 474         NTSTATUS status;
 475
 476         if (!fsp->fsp_flags.is_pathref) {
 477                 ret = ioctl(fsp_fd, FS_IOC_GETFLAGS, &flags);
 478                 if (ret < 0) {
 479                         DBG_WARNING("FS_IOC_GETFLAGS failed: %s, fd %lld\n",
 480                                     strerror(errno), (long long)fd);
 481                         return map_nt_error_from_unix(errno);
 482                 }
 483                 if (flags & FS_COMPR_FL) {
 484                         *_compression_fmt = COMPRESSION_FORMAT_LZNT1;
 485                 } else {
 486                         *_compression_fmt = COMPRESSION_FORMAT_NONE;
 487                 }
 488                 return NT_STATUS_OK;
 489         }
 490
 491         if (!fsp->fsp_flags.have_proc_fds) {
 492                 return NT_STATUS_NOT_IMPLEMENTED;
 493         }
 494
 495         fd = open(sys_proc_fd_path(fsp_fd, &buf), O_RDONLY);
 496         if (fd == -1) {
 497                 DBG_DEBUG("/proc open of %s failed: %s\n",
 498                           buf.buf,
 499                           strerror(errno));
 500                 return map_nt_error_from_unix(errno);
 501         }
 502
 503         ret = ioctl(fd, FS_IOC_GETFLAGS, &flags);
 504         if (ret < 0) {
 505                 DEBUG(1, ("FS_IOC_GETFLAGS failed: %s, fd %lld\n",
 506                           strerror(errno), (long long)fd));
 507                 status = map_nt_error_from_unix(errno);
 508                 goto err_close;
 509         }
 510         if (flags & FS_COMPR_FL) {
 511                 *_compression_fmt = COMPRESSION_FORMAT_LZNT1;
 512         } else {
 513                 *_compression_fmt = COMPRESSION_FORMAT_NONE;
 514         }
 515         status = NT_STATUS_OK;
 516
 517 err_close:
 518         if (fd != -1) {
 519                 close(fd);
 520         }
 521
 522         return status;
 523 }
 524
 525 static NTSTATUS btrfs_set_compression(struct vfs_handle_struct *handle,
 526                                       TALLOC_CTX *mem_ctx,
 527                                       struct files_struct *fsp,
 528                                       uint16_t compression_fmt)
 529 {
 530         int ret;
 531         long flags = 0;
 532         int fd;
 533         NTSTATUS status;
 534
 535         if ((fsp == NULL) || (fsp_get_io_fd(fsp) == -1)) {
 536                 status = NT_STATUS_INVALID_PARAMETER;
 537                 goto err_out;
 538         }
 539         fd = fsp_get_io_fd(fsp);
 540
 541         ret = ioctl(fd, FS_IOC_GETFLAGS, &flags);
 542         if (ret < 0) {
 543                 DEBUG(1, ("FS_IOC_GETFLAGS failed: %s, fd %d\n",
 544                           strerror(errno), fd));
 545                 status = map_nt_error_from_unix(errno);
 546                 goto err_out;
 547         }
 548
 549         if (compression_fmt == COMPRESSION_FORMAT_NONE) {
 550                 DEBUG(5, ("setting compression\n"));
 551                 flags &= (~FS_COMPR_FL);
 552         } else if ((compression_fmt == COMPRESSION_FORMAT_DEFAULT)
 553                 || (compression_fmt == COMPRESSION_FORMAT_LZNT1)) {
 554                 DEBUG(5, ("clearing compression\n"));
 555                 flags |= FS_COMPR_FL;
 556         } else {
 557                 DEBUG(1, ("invalid compression format 0x%x\n",
 558                           (int)compression_fmt));
 559                 status = NT_STATUS_INVALID_PARAMETER;
 560                 goto err_out;
 561         }
 562
 563         ret = ioctl(fd, FS_IOC_SETFLAGS, &flags);
 564         if (ret < 0) {
 565                 DEBUG(1, ("FS_IOC_SETFLAGS failed: %s, fd %d\n",
 566                           strerror(errno), fd));
 567                 status = map_nt_error_from_unix(errno);
 568                 goto err_out;
 569         }
 570         status = NT_STATUS_OK;
 571 err_out:
 572         return status;
 573 }
 574
 575 /*
 576  * Check whether a path can be shadow copied. Return the base volume, allowing
 577  * the caller to determine if multiple paths lie on the same base volume.
 578  */
 579 #define BTRFS_INODE_SUBVOL 256
 580 static NTSTATUS btrfs_snap_check_path(struct vfs_handle_struct *handle,
 581                                       TALLOC_CTX *mem_ctx,
 582                                       const char *service_path,
 583                                       char **base_volume)
 584 {
 585         struct stat st;
 586         char *base;
 587
 588         if (!lp_parm_bool(SNUM(handle->conn),
 589                          "btrfs", "manipulate snapshots", false)) {
 590                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 591                 return SMB_VFS_NEXT_SNAP_CHECK_PATH(handle, mem_ctx,
 592                                                     service_path, base_volume);
 593         }
 594
 595         /* btrfs userspace uses this logic to confirm subvolume */
 596         if (stat(service_path, &st) < 0) {
 597                 return NT_STATUS_NOT_SUPPORTED;
 598         }
 599         if ((st.st_ino != BTRFS_INODE_SUBVOL) || !S_ISDIR(st.st_mode)) {
 600                 DEBUG(0, ("%s not a btrfs subvolume, snapshots not available\n",
 601                           service_path));
 602                 return NT_STATUS_NOT_SUPPORTED;
 603         }
 604
 605         /* we "snapshot" the service path itself */
 606         base = talloc_strdup(mem_ctx, service_path);
 607         if (base == NULL) {
 608                 return NT_STATUS_NO_MEMORY;
 609         }
 610         *base_volume = base;
 611
 612         return NT_STATUS_OK;
 613 }
 614
 615 static NTSTATUS btrfs_gen_snap_dest_path(TALLOC_CTX *mem_ctx,
 616                                          const char *src_path,
 617                                          time_t *tstamp,
 618                                          char **dest_path, char **subvolume)
 619 {
 620         struct tm t_gmt;
 621         char time_str[50];
 622         size_t tlen;
 623
 624         gmtime_r(tstamp, &t_gmt);
 625
 626         tlen = strftime(time_str, ARRAY_SIZE(time_str),
 627                         SHADOW_COPY_PATH_FORMAT, &t_gmt);
 628         if (tlen <= 0) {
 629                 return NT_STATUS_UNSUCCESSFUL;
 630         }
 631
 632         *dest_path = talloc_strdup(mem_ctx, src_path);
 633         *subvolume = talloc_strdup(mem_ctx, time_str);
 634         if ((*dest_path == NULL) || (*subvolume == NULL)) {
 635                 return NT_STATUS_NO_MEMORY;
 636         }
 637
 638         return NT_STATUS_OK;
 639 }
 640
 641 static NTSTATUS btrfs_snap_create(struct vfs_handle_struct *handle,
 642                                   TALLOC_CTX *mem_ctx,
 643                                   const char *base_volume,
 644                                   time_t *tstamp,
 645                                   bool rw,
 646                                   char **_base_path,
 647                                   char **_snap_path)
 648 {
 649         struct btrfs_ioctl_vol_args_v2 ioctl_arg;
 650         DIR *src_dir;
 651         DIR *dest_dir;
 652         int src_fd;
 653         int dest_fd;
 654         char *dest_path = NULL;
 655         char *dest_subvolume = NULL;
 656         int ret;
 657         NTSTATUS status;
 658         char *base_path;
 659         char *snap_path;
 660         TALLOC_CTX *tmp_ctx;
 661         int saved_errno;
 662         size_t len;
 663
 664         if (!lp_parm_bool(SNUM(handle->conn),
 665                           "btrfs", "manipulate snapshots", false)) {
 666                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 667                 return SMB_VFS_NEXT_SNAP_CREATE(handle, mem_ctx, base_volume,
 668                                                 tstamp, rw, _base_path,
 669                                                 _snap_path);
 670         }
 671
 672         tmp_ctx = talloc_new(mem_ctx);
 673         if (tmp_ctx == NULL) {
 674                 return NT_STATUS_NO_MEMORY;
 675         }
 676
 677         base_path = talloc_strdup(tmp_ctx, base_volume);
 678         if (base_path == NULL) {
 679                 talloc_free(tmp_ctx);
 680                 return NT_STATUS_NO_MEMORY;
 681         }
 682
 683         status = btrfs_gen_snap_dest_path(tmp_ctx, base_volume, tstamp,
 684                                           &dest_path, &dest_subvolume);
 685         if (!NT_STATUS_IS_OK(status)) {
 686                 talloc_free(tmp_ctx);
 687                 return status;
 688         }
 689
 690         snap_path = talloc_asprintf(tmp_ctx, "%s/%s", dest_path,
 691                                     dest_subvolume);
 692         if (snap_path == NULL) {
 693                 talloc_free(tmp_ctx);
 694                 return NT_STATUS_NO_MEMORY;
 695         }
 696
 697         src_dir = opendir(base_volume);
 698         if (src_dir == NULL) {
 699                 DEBUG(0, ("snap src %s open failed: %s\n",
 700                           base_volume, strerror(errno)));
 701                 status = map_nt_error_from_unix(errno);
 702                 talloc_free(tmp_ctx);
 703                 return status;
 704         }
 705         src_fd = dirfd(src_dir);
 706         if (src_fd < 0) {
 707                 status = map_nt_error_from_unix(errno);
 708                 closedir(src_dir);
 709                 talloc_free(tmp_ctx);
 710                 return status;
 711         }
 712
 713         dest_dir = opendir(dest_path);
 714         if (dest_dir == NULL) {
 715                 DEBUG(0, ("snap dest %s open failed: %s\n",
 716                           dest_path, strerror(errno)));
 717                 status = map_nt_error_from_unix(errno);
 718                 closedir(src_dir);
 719                 talloc_free(tmp_ctx);
 720                 return status;
 721         }
 722         dest_fd = dirfd(dest_dir);
 723         if (dest_fd < 0) {
 724                 status = map_nt_error_from_unix(errno);
 725                 closedir(src_dir);
 726                 closedir(dest_dir);
 727                 talloc_free(tmp_ctx);
 728                 return status;
 729         }
 730
 731         /* avoid zeroing the entire struct here, name is 4k */
 732         ioctl_arg.fd = src_fd;
 733         ioctl_arg.transid = 0;
 734         ioctl_arg.flags = (rw == false) ? BTRFS_SUBVOL_RDONLY : 0;
 735         memset(ioctl_arg.unused, 0, sizeof(ioctl_arg.unused));
 736         len = strlcpy(ioctl_arg.name, dest_subvolume,
 737                       ARRAY_SIZE(ioctl_arg.name));
 738         if (len >= ARRAY_SIZE(ioctl_arg.name)) {
 739                 DEBUG(1, ("subvolume name too long for SNAP_CREATE ioctl\n"));
 740                 closedir(src_dir);
 741                 closedir(dest_dir);
 742                 talloc_free(tmp_ctx);
 743                 return NT_STATUS_INVALID_PARAMETER;
 744         }
 745
 746         become_root();
 747         ret = ioctl(dest_fd, BTRFS_IOC_SNAP_CREATE_V2, &ioctl_arg);
 748         saved_errno = errno;
 749         unbecome_root();
 750         if (ret < 0) {
 751                 DEBUG(0, ("%s -> %s(%s) BTRFS_IOC_SNAP_CREATE_V2 failed: %s\n",
 752                           base_volume, dest_path, dest_subvolume,
 753                           strerror(saved_errno)));
 754                 status = map_nt_error_from_unix(saved_errno);
 755                 closedir(src_dir);
 756                 closedir(dest_dir);
 757                 talloc_free(tmp_ctx);
 758                 return status;
 759         }
 760         DEBUG(5, ("%s -> %s(%s) BTRFS_IOC_SNAP_CREATE_V2 done\n",
 761                   base_volume, dest_path, dest_subvolume));
 762
 763         *_base_path = talloc_steal(mem_ctx, base_path);
 764         *_snap_path = talloc_steal(mem_ctx, snap_path);
 765         closedir(src_dir);
 766         closedir(dest_dir);
 767         talloc_free(tmp_ctx);
 768
 769         return NT_STATUS_OK;
 770 }
 771
 772 static NTSTATUS btrfs_snap_delete(struct vfs_handle_struct *handle,
 773                                   TALLOC_CTX *mem_ctx,
 774                                   char *base_path,
 775                                   char *snap_path)
 776 {
 777         char *tstr;
 778         struct tm t_gmt = {};
 779         DIR *dest_dir;
 780         int dest_fd;
 781         struct btrfs_ioctl_vol_args ioctl_arg;
 782         int ret;
 783         NTSTATUS status;
 784         char *dest_path;
 785         char *subvolume;
 786         TALLOC_CTX *tmp_ctx;
 787         int saved_errno;
 788         size_t len;
 789
 790         if (!lp_parm_bool(SNUM(handle->conn),
 791                           "btrfs", "manipulate snapshots", false)) {
 792                 DEBUG(2, ("Btrfs snapshot manipulation disabled, passing\n"));
 793                 return SMB_VFS_NEXT_SNAP_DELETE(handle, mem_ctx,
 794                                                 base_path, snap_path);
 795         }
 796
 797         tmp_ctx = talloc_new(mem_ctx);
 798         if (tmp_ctx == NULL) {
 799                 return NT_STATUS_NO_MEMORY;
 800         }
 801
 802         dest_path = talloc_strdup(tmp_ctx, snap_path);
 803         if (dest_path == NULL) {
 804                 talloc_free(tmp_ctx);
 805                 return NT_STATUS_NO_MEMORY;
 806         }
 807         subvolume = talloc_strdup(tmp_ctx, snap_path);
 808         if (subvolume == NULL) {
 809                 talloc_free(tmp_ctx);
 810                 return NT_STATUS_NO_MEMORY;
 811         }
 812         dest_path = dirname(dest_path);
 813         subvolume = basename(subvolume);
 814
 815         /* confirm snap_path matches creation format */
 816         tstr = strptime(subvolume, SHADOW_COPY_PATH_FORMAT, &t_gmt);
 817         if ((tstr == NULL) || (*tstr != '\0')) {
 818                 DEBUG(0, ("snapshot path %s does not match creation format\n",
 819                           snap_path));
 820                 talloc_free(tmp_ctx);
 821                 return NT_STATUS_UNSUCCESSFUL;
 822         }
 823
 824         dest_dir = opendir(dest_path);
 825         if (dest_dir == NULL) {
 826                 DEBUG(0, ("snap destroy dest %s open failed: %s\n",
 827                           dest_path, strerror(errno)));
 828                 status = map_nt_error_from_unix(errno);
 829                 talloc_free(tmp_ctx);
 830                 return status;
 831         }
 832         dest_fd = dirfd(dest_dir);
 833         if (dest_fd < 0) {
 834                 status = map_nt_error_from_unix(errno);
 835                 closedir(dest_dir);
 836                 talloc_free(tmp_ctx);
 837                 return status;
 838         }
 839
 840         ioctl_arg.fd = -1;      /* not needed */
 841         len = strlcpy(ioctl_arg.name, subvolume, ARRAY_SIZE(ioctl_arg.name));
 842         if (len >= ARRAY_SIZE(ioctl_arg.name)) {
 843                 DEBUG(1, ("subvolume name too long for SNAP_DESTROY ioctl\n"));
 844                 closedir(dest_dir);
 845                 talloc_free(tmp_ctx);
 846                 return NT_STATUS_INVALID_PARAMETER;
 847         }
 848
 849         become_root();
 850         ret = ioctl(dest_fd, BTRFS_IOC_SNAP_DESTROY, &ioctl_arg);
 851         saved_errno = errno;
 852         unbecome_root();
 853         if (ret < 0) {
 854                 DEBUG(0, ("%s(%s) BTRFS_IOC_SNAP_DESTROY failed: %s\n",
 855                           dest_path, subvolume, strerror(saved_errno)));
 856                 status = map_nt_error_from_unix(saved_errno);
 857                 closedir(dest_dir);
 858                 talloc_free(tmp_ctx);
 859                 return status;
 860         }
 861         DEBUG(5, ("%s(%s) BTRFS_IOC_SNAP_DESTROY done\n",
 862                   dest_path, subvolume));
 863
 864         closedir(dest_dir);
 865         talloc_free(tmp_ctx);
 866         return NT_STATUS_OK;
 867 }
 868
 869 static struct vfs_fn_pointers btrfs_fns = {
 870         .fs_capabilities_fn = btrfs_fs_capabilities,
 871         .offload_read_send_fn = btrfs_offload_read_send,
 872         .offload_read_recv_fn = btrfs_offload_read_recv,
 873         .offload_write_send_fn = btrfs_offload_write_send,
 874         .offload_write_recv_fn = btrfs_offload_write_recv,
 875         .fget_compression_fn = btrfs_fget_compression,
 876         .set_compression_fn = btrfs_set_compression,
 877         .snap_check_path_fn = btrfs_snap_check_path,
 878         .snap_create_fn = btrfs_snap_create,
 879         .snap_delete_fn = btrfs_snap_delete,
 880 };
 881
 882 static_decl_vfs;
 883 NTSTATUS vfs_btrfs_init(TALLOC_CTX *ctx)
 884 {
 885         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 886                                 "btrfs", &btrfs_fns);
 887 }