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