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