fs/xfs/xfs_fsmap.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017 Oracle.  All Rights Reserved.
   4  * Author: Darrick J. Wong <darrick.wong@oracle.com>
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_mount.h"
  13 #include "xfs_inode.h"
  14 #include "xfs_trans.h"
  15 #include "xfs_btree.h"
  16 #include "xfs_rmap_btree.h"
  17 #include "xfs_trace.h"
  18 #include "xfs_rmap.h"
  19 #include "xfs_alloc.h"
  20 #include "xfs_bit.h"
  21 #include <linux/fsmap.h>
  22 #include "xfs_fsmap.h"
  23 #include "xfs_refcount.h"
  24 #include "xfs_refcount_btree.h"
  25 #include "xfs_alloc_btree.h"
  26 #include "xfs_rtbitmap.h"
  27 #include "xfs_ag.h"
  28
  29 /* Convert an xfs_fsmap to an fsmap. */
  30 static void
  31 xfs_fsmap_from_internal(
  32         struct fsmap            *dest,
  33         struct xfs_fsmap        *src)
  34 {
  35         dest->fmr_device = src->fmr_device;
  36         dest->fmr_flags = src->fmr_flags;
  37         dest->fmr_physical = BBTOB(src->fmr_physical);
  38         dest->fmr_owner = src->fmr_owner;
  39         dest->fmr_offset = BBTOB(src->fmr_offset);
  40         dest->fmr_length = BBTOB(src->fmr_length);
  41         dest->fmr_reserved[0] = 0;
  42         dest->fmr_reserved[1] = 0;
  43         dest->fmr_reserved[2] = 0;
  44 }
  45
  46 /* Convert an fsmap to an xfs_fsmap. */
  47 void
  48 xfs_fsmap_to_internal(
  49         struct xfs_fsmap        *dest,
  50         struct fsmap            *src)
  51 {
  52         dest->fmr_device = src->fmr_device;
  53         dest->fmr_flags = src->fmr_flags;
  54         dest->fmr_physical = BTOBBT(src->fmr_physical);
  55         dest->fmr_owner = src->fmr_owner;
  56         dest->fmr_offset = BTOBBT(src->fmr_offset);
  57         dest->fmr_length = BTOBBT(src->fmr_length);
  58 }
  59
  60 /* Convert an fsmap owner into an rmapbt owner. */
  61 static int
  62 xfs_fsmap_owner_to_rmap(
  63         struct xfs_rmap_irec    *dest,
  64         const struct xfs_fsmap  *src)
  65 {
  66         if (!(src->fmr_flags & FMR_OF_SPECIAL_OWNER)) {
  67                 dest->rm_owner = src->fmr_owner;
  68                 return 0;
  69         }
  70
  71         switch (src->fmr_owner) {
  72         case 0:                 /* "lowest owner id possible" */
  73         case -1ULL:             /* "highest owner id possible" */
  74                 dest->rm_owner = 0;
  75                 break;
  76         case XFS_FMR_OWN_FREE:
  77                 dest->rm_owner = XFS_RMAP_OWN_NULL;
  78                 break;
  79         case XFS_FMR_OWN_UNKNOWN:
  80                 dest->rm_owner = XFS_RMAP_OWN_UNKNOWN;
  81                 break;
  82         case XFS_FMR_OWN_FS:
  83                 dest->rm_owner = XFS_RMAP_OWN_FS;
  84                 break;
  85         case XFS_FMR_OWN_LOG:
  86                 dest->rm_owner = XFS_RMAP_OWN_LOG;
  87                 break;
  88         case XFS_FMR_OWN_AG:
  89                 dest->rm_owner = XFS_RMAP_OWN_AG;
  90                 break;
  91         case XFS_FMR_OWN_INOBT:
  92                 dest->rm_owner = XFS_RMAP_OWN_INOBT;
  93                 break;
  94         case XFS_FMR_OWN_INODES:
  95                 dest->rm_owner = XFS_RMAP_OWN_INODES;
  96                 break;
  97         case XFS_FMR_OWN_REFC:
  98                 dest->rm_owner = XFS_RMAP_OWN_REFC;
  99                 break;
 100         case XFS_FMR_OWN_COW:
 101                 dest->rm_owner = XFS_RMAP_OWN_COW;
 102                 break;
 103         case XFS_FMR_OWN_DEFECTIVE:     /* not implemented */
 104                 /* fall through */
 105         default:
 106                 return -EINVAL;
 107         }
 108         return 0;
 109 }
 110
 111 /* Convert an rmapbt owner into an fsmap owner. */
 112 static int
 113 xfs_fsmap_owner_from_rmap(
 114         struct xfs_fsmap                *dest,
 115         const struct xfs_rmap_irec      *src)
 116 {
 117         dest->fmr_flags = 0;
 118         if (!XFS_RMAP_NON_INODE_OWNER(src->rm_owner)) {
 119                 dest->fmr_owner = src->rm_owner;
 120                 return 0;
 121         }
 122         dest->fmr_flags |= FMR_OF_SPECIAL_OWNER;
 123
 124         switch (src->rm_owner) {
 125         case XFS_RMAP_OWN_FS:
 126                 dest->fmr_owner = XFS_FMR_OWN_FS;
 127                 break;
 128         case XFS_RMAP_OWN_LOG:
 129                 dest->fmr_owner = XFS_FMR_OWN_LOG;
 130                 break;
 131         case XFS_RMAP_OWN_AG:
 132                 dest->fmr_owner = XFS_FMR_OWN_AG;
 133                 break;
 134         case XFS_RMAP_OWN_INOBT:
 135                 dest->fmr_owner = XFS_FMR_OWN_INOBT;
 136                 break;
 137         case XFS_RMAP_OWN_INODES:
 138                 dest->fmr_owner = XFS_FMR_OWN_INODES;
 139                 break;
 140         case XFS_RMAP_OWN_REFC:
 141                 dest->fmr_owner = XFS_FMR_OWN_REFC;
 142                 break;
 143         case XFS_RMAP_OWN_COW:
 144                 dest->fmr_owner = XFS_FMR_OWN_COW;
 145                 break;
 146         case XFS_RMAP_OWN_NULL: /* "free" */
 147                 dest->fmr_owner = XFS_FMR_OWN_FREE;
 148                 break;
 149         default:
 150                 ASSERT(0);
 151                 return -EFSCORRUPTED;
 152         }
 153         return 0;
 154 }
 155
 156 /* getfsmap query state */
 157 struct xfs_getfsmap_info {
 158         struct xfs_fsmap_head   *head;
 159         struct fsmap            *fsmap_recs;    /* mapping records */
 160         struct xfs_buf          *agf_bp;        /* AGF, for refcount queries */
 161         struct xfs_perag        *pag;           /* AG info, if applicable */
 162         xfs_daddr_t             next_daddr;     /* next daddr we expect */
 163         /* daddr of low fsmap key when we're using the rtbitmap */
 164         xfs_daddr_t             low_daddr;
 165         u64                     missing_owner;  /* owner of holes */
 166         u32                     dev;            /* device id */
 167         /*
 168          * Low rmap key for the query.  If low.rm_blockcount is nonzero, this
 169          * is the second (or later) call to retrieve the recordset in pieces.
 170          * xfs_getfsmap_rec_before_start will compare all records retrieved
 171          * by the rmapbt query to filter out any records that start before
 172          * the last record.
 173          */
 174         struct xfs_rmap_irec    low;
 175         struct xfs_rmap_irec    high;           /* high rmap key */
 176         bool                    last;           /* last extent? */
 177 };
 178
 179 /* Associate a device with a getfsmap handler. */
 180 struct xfs_getfsmap_dev {
 181         u32                     dev;
 182         int                     (*fn)(struct xfs_trans *tp,
 183                                       const struct xfs_fsmap *keys,
 184                                       struct xfs_getfsmap_info *info);
 185 };
 186
 187 /* Compare two getfsmap device handlers. */
 188 static int
 189 xfs_getfsmap_dev_compare(
 190         const void                      *p1,
 191         const void                      *p2)
 192 {
 193         const struct xfs_getfsmap_dev   *d1 = p1;
 194         const struct xfs_getfsmap_dev   *d2 = p2;
 195
 196         return d1->dev - d2->dev;
 197 }
 198
 199 /* Decide if this mapping is shared. */
 200 STATIC int
 201 xfs_getfsmap_is_shared(
 202         struct xfs_trans                *tp,
 203         struct xfs_getfsmap_info        *info,
 204         const struct xfs_rmap_irec      *rec,
 205         bool                            *stat)
 206 {
 207         struct xfs_mount                *mp = tp->t_mountp;
 208         struct xfs_btree_cur            *cur;
 209         xfs_agblock_t                   fbno;
 210         xfs_extlen_t                    flen;
 211         int                             error;
 212
 213         *stat = false;
 214         if (!xfs_has_reflink(mp))
 215                 return 0;
 216         /* rt files will have no perag structure */
 217         if (!info->pag)
 218                 return 0;
 219
 220         /* Are there any shared blocks here? */
 221         flen = 0;
 222         cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp, info->pag);
 223
 224         error = xfs_refcount_find_shared(cur, rec->rm_startblock,
 225                         rec->rm_blockcount, &fbno, &flen, false);
 226
 227         xfs_btree_del_cursor(cur, error);
 228         if (error)
 229                 return error;
 230
 231         *stat = flen > 0;
 232         return 0;
 233 }
 234
 235 static inline void
 236 xfs_getfsmap_format(
 237         struct xfs_mount                *mp,
 238         struct xfs_fsmap                *xfm,
 239         struct xfs_getfsmap_info        *info)
 240 {
 241         struct fsmap                    *rec;
 242
 243         trace_xfs_getfsmap_mapping(mp, xfm);
 244
 245         rec = &info->fsmap_recs[info->head->fmh_entries++];
 246         xfs_fsmap_from_internal(rec, xfm);
 247 }
 248
 249 static inline bool
 250 xfs_getfsmap_rec_before_start(
 251         struct xfs_getfsmap_info        *info,
 252         const struct xfs_rmap_irec      *rec,
 253         xfs_daddr_t                     rec_daddr)
 254 {
 255         if (info->low_daddr != -1ULL)
 256                 return rec_daddr < info->low_daddr;
 257         if (info->low.rm_blockcount)
 258                 return xfs_rmap_compare(rec, &info->low) < 0;
 259         return false;
 260 }
 261
 262 /*
 263  * Format a reverse mapping for getfsmap, having translated rm_startblock
 264  * into the appropriate daddr units.  Pass in a nonzero @len_daddr if the
 265  * length could be larger than rm_blockcount in struct xfs_rmap_irec.
 266  */
 267 STATIC int
 268 xfs_getfsmap_helper(
 269         struct xfs_trans                *tp,
 270         struct xfs_getfsmap_info        *info,
 271         const struct xfs_rmap_irec      *rec,
 272         xfs_daddr_t                     rec_daddr,
 273         xfs_daddr_t                     len_daddr)
 274 {
 275         struct xfs_fsmap                fmr;
 276         struct xfs_mount                *mp = tp->t_mountp;
 277         bool                            shared;
 278         int                             error;
 279
 280         if (fatal_signal_pending(current))
 281                 return -EINTR;
 282
 283         if (len_daddr == 0)
 284                 len_daddr = XFS_FSB_TO_BB(mp, rec->rm_blockcount);
 285
 286         /*
 287          * Filter out records that start before our startpoint, if the
 288          * caller requested that.
 289          */
 290         if (xfs_getfsmap_rec_before_start(info, rec, rec_daddr)) {
 291                 rec_daddr += len_daddr;
 292                 if (info->next_daddr < rec_daddr)
 293                         info->next_daddr = rec_daddr;
 294                 return 0;
 295         }
 296
 297         /* Are we just counting mappings? */
 298         if (info->head->fmh_count == 0) {
 299                 if (info->head->fmh_entries == UINT_MAX)
 300                         return -ECANCELED;
 301
 302                 if (rec_daddr > info->next_daddr)
 303                         info->head->fmh_entries++;
 304
 305                 if (info->last)
 306                         return 0;
 307
 308                 info->head->fmh_entries++;
 309
 310                 rec_daddr += len_daddr;
 311                 if (info->next_daddr < rec_daddr)
 312                         info->next_daddr = rec_daddr;
 313                 return 0;
 314         }
 315
 316         /*
 317          * If the record starts past the last physical block we saw,
 318          * then we've found a gap.  Report the gap as being owned by
 319          * whatever the caller specified is the missing owner.
 320          */
 321         if (rec_daddr > info->next_daddr) {
 322                 if (info->head->fmh_entries >= info->head->fmh_count)
 323                         return -ECANCELED;
 324
 325                 fmr.fmr_device = info->dev;
 326                 fmr.fmr_physical = info->next_daddr;
 327                 fmr.fmr_owner = info->missing_owner;
 328                 fmr.fmr_offset = 0;
 329                 fmr.fmr_length = rec_daddr - info->next_daddr;
 330                 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
 331                 xfs_getfsmap_format(mp, &fmr, info);
 332         }
 333
 334         if (info->last)
 335                 goto out;
 336
 337         /* Fill out the extent we found */
 338         if (info->head->fmh_entries >= info->head->fmh_count)
 339                 return -ECANCELED;
 340
 341         trace_xfs_fsmap_mapping(mp, info->dev,
 342                         info->pag ? info->pag->pag_agno : NULLAGNUMBER, rec);
 343
 344         fmr.fmr_device = info->dev;
 345         fmr.fmr_physical = rec_daddr;
 346         error = xfs_fsmap_owner_from_rmap(&fmr, rec);
 347         if (error)
 348                 return error;
 349         fmr.fmr_offset = XFS_FSB_TO_BB(mp, rec->rm_offset);
 350         fmr.fmr_length = len_daddr;
 351         if (rec->rm_flags & XFS_RMAP_UNWRITTEN)
 352                 fmr.fmr_flags |= FMR_OF_PREALLOC;
 353         if (rec->rm_flags & XFS_RMAP_ATTR_FORK)
 354                 fmr.fmr_flags |= FMR_OF_ATTR_FORK;
 355         if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
 356                 fmr.fmr_flags |= FMR_OF_EXTENT_MAP;
 357         if (fmr.fmr_flags == 0) {
 358                 error = xfs_getfsmap_is_shared(tp, info, rec, &shared);
 359                 if (error)
 360                         return error;
 361                 if (shared)
 362                         fmr.fmr_flags |= FMR_OF_SHARED;
 363         }
 364
 365         xfs_getfsmap_format(mp, &fmr, info);
 366 out:
 367         rec_daddr += len_daddr;
 368         if (info->next_daddr < rec_daddr)
 369                 info->next_daddr = rec_daddr;
 370         return 0;
 371 }
 372
 373 /* Transform a rmapbt irec into a fsmap */
 374 STATIC int
 375 xfs_getfsmap_datadev_helper(
 376         struct xfs_btree_cur            *cur,
 377         const struct xfs_rmap_irec      *rec,
 378         void                            *priv)
 379 {
 380         struct xfs_mount                *mp = cur->bc_mp;
 381         struct xfs_getfsmap_info        *info = priv;
 382         xfs_fsblock_t                   fsb;
 383         xfs_daddr_t                     rec_daddr;
 384
 385         fsb = XFS_AGB_TO_FSB(mp, cur->bc_ag.pag->pag_agno, rec->rm_startblock);
 386         rec_daddr = XFS_FSB_TO_DADDR(mp, fsb);
 387
 388         return xfs_getfsmap_helper(cur->bc_tp, info, rec, rec_daddr, 0);
 389 }
 390
 391 /* Transform a bnobt irec into a fsmap */
 392 STATIC int
 393 xfs_getfsmap_datadev_bnobt_helper(
 394         struct xfs_btree_cur            *cur,
 395         const struct xfs_alloc_rec_incore *rec,
 396         void                            *priv)
 397 {
 398         struct xfs_mount                *mp = cur->bc_mp;
 399         struct xfs_getfsmap_info        *info = priv;
 400         struct xfs_rmap_irec            irec;
 401         xfs_daddr_t                     rec_daddr;
 402
 403         rec_daddr = XFS_AGB_TO_DADDR(mp, cur->bc_ag.pag->pag_agno,
 404                         rec->ar_startblock);
 405
 406         irec.rm_startblock = rec->ar_startblock;
 407         irec.rm_blockcount = rec->ar_blockcount;
 408         irec.rm_owner = XFS_RMAP_OWN_NULL;      /* "free" */
 409         irec.rm_offset = 0;
 410         irec.rm_flags = 0;
 411
 412         return xfs_getfsmap_helper(cur->bc_tp, info, &irec, rec_daddr, 0);
 413 }
 414
 415 /* Set rmap flags based on the getfsmap flags */
 416 static void
 417 xfs_getfsmap_set_irec_flags(
 418         struct xfs_rmap_irec    *irec,
 419         const struct xfs_fsmap  *fmr)
 420 {
 421         irec->rm_flags = 0;
 422         if (fmr->fmr_flags & FMR_OF_ATTR_FORK)
 423                 irec->rm_flags |= XFS_RMAP_ATTR_FORK;
 424         if (fmr->fmr_flags & FMR_OF_EXTENT_MAP)
 425                 irec->rm_flags |= XFS_RMAP_BMBT_BLOCK;
 426         if (fmr->fmr_flags & FMR_OF_PREALLOC)
 427                 irec->rm_flags |= XFS_RMAP_UNWRITTEN;
 428 }
 429
 430 /* Execute a getfsmap query against the log device. */
 431 STATIC int
 432 xfs_getfsmap_logdev(
 433         struct xfs_trans                *tp,
 434         const struct xfs_fsmap          *keys,
 435         struct xfs_getfsmap_info        *info)
 436 {
 437         struct xfs_mount                *mp = tp->t_mountp;
 438         struct xfs_rmap_irec            rmap;
 439         xfs_daddr_t                     rec_daddr, len_daddr;
 440         xfs_fsblock_t                   start_fsb, end_fsb;
 441         uint64_t                        eofs;
 442
 443         eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
 444         if (keys[0].fmr_physical >= eofs)
 445                 return 0;
 446         start_fsb = XFS_BB_TO_FSBT(mp,
 447                                 keys[0].fmr_physical + keys[0].fmr_length);
 448         end_fsb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
 449
 450         /* Adjust the low key if we are continuing from where we left off. */
 451         if (keys[0].fmr_length > 0)
 452                 info->low_daddr = XFS_FSB_TO_BB(mp, start_fsb);
 453
 454         trace_xfs_fsmap_low_key_linear(mp, info->dev, start_fsb);
 455         trace_xfs_fsmap_high_key_linear(mp, info->dev, end_fsb);
 456
 457         if (start_fsb > 0)
 458                 return 0;
 459
 460         /* Fabricate an rmap entry for the external log device. */
 461         rmap.rm_startblock = 0;
 462         rmap.rm_blockcount = mp->m_sb.sb_logblocks;
 463         rmap.rm_owner = XFS_RMAP_OWN_LOG;
 464         rmap.rm_offset = 0;
 465         rmap.rm_flags = 0;
 466
 467         rec_daddr = XFS_FSB_TO_BB(mp, rmap.rm_startblock);
 468         len_daddr = XFS_FSB_TO_BB(mp, rmap.rm_blockcount);
 469         return xfs_getfsmap_helper(tp, info, &rmap, rec_daddr, len_daddr);
 470 }
 471
 472 #ifdef CONFIG_XFS_RT
 473 /* Transform a rtbitmap "record" into a fsmap */
 474 STATIC int
 475 xfs_getfsmap_rtdev_rtbitmap_helper(
 476         struct xfs_mount                *mp,
 477         struct xfs_trans                *tp,
 478         const struct xfs_rtalloc_rec    *rec,
 479         void                            *priv)
 480 {
 481         struct xfs_getfsmap_info        *info = priv;
 482         struct xfs_rmap_irec            irec;
 483         xfs_rtblock_t                   rtbno;
 484         xfs_daddr_t                     rec_daddr, len_daddr;
 485
 486         rtbno = xfs_rtx_to_rtb(mp, rec->ar_startext);
 487         rec_daddr = XFS_FSB_TO_BB(mp, rtbno);
 488         irec.rm_startblock = rtbno;
 489
 490         rtbno = xfs_rtx_to_rtb(mp, rec->ar_extcount);
 491         len_daddr = XFS_FSB_TO_BB(mp, rtbno);
 492         irec.rm_blockcount = rtbno;
 493
 494         irec.rm_owner = XFS_RMAP_OWN_NULL;      /* "free" */
 495         irec.rm_offset = 0;
 496         irec.rm_flags = 0;
 497
 498         return xfs_getfsmap_helper(tp, info, &irec, rec_daddr, len_daddr);
 499 }
 500
 501 /* Execute a getfsmap query against the realtime device rtbitmap. */
 502 STATIC int
 503 xfs_getfsmap_rtdev_rtbitmap(
 504         struct xfs_trans                *tp,
 505         const struct xfs_fsmap          *keys,
 506         struct xfs_getfsmap_info        *info)
 507 {
 508
 509         struct xfs_rtalloc_rec          alow = { 0 };
 510         struct xfs_rtalloc_rec          ahigh = { 0 };
 511         struct xfs_mount                *mp = tp->t_mountp;
 512         xfs_rtblock_t                   start_rtb;
 513         xfs_rtblock_t                   end_rtb;
 514         uint64_t                        eofs;
 515         int                             error;
 516
 517         eofs = XFS_FSB_TO_BB(mp, xfs_rtx_to_rtb(mp, mp->m_sb.sb_rextents));
 518         if (keys[0].fmr_physical >= eofs)
 519                 return 0;
 520         start_rtb = XFS_BB_TO_FSBT(mp,
 521                                 keys[0].fmr_physical + keys[0].fmr_length);
 522         end_rtb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
 523
 524         info->missing_owner = XFS_FMR_OWN_UNKNOWN;
 525
 526         /* Adjust the low key if we are continuing from where we left off. */
 527         if (keys[0].fmr_length > 0) {
 528                 info->low_daddr = XFS_FSB_TO_BB(mp, start_rtb);
 529                 if (info->low_daddr >= eofs)
 530                         return 0;
 531         }
 532
 533         trace_xfs_fsmap_low_key_linear(mp, info->dev, start_rtb);
 534         trace_xfs_fsmap_high_key_linear(mp, info->dev, end_rtb);
 535
 536         xfs_ilock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
 537
 538         /*
 539          * Set up query parameters to return free rtextents covering the range
 540          * we want.
 541          */
 542         alow.ar_startext = xfs_rtb_to_rtx(mp, start_rtb);
 543         ahigh.ar_startext = xfs_rtb_to_rtxup(mp, end_rtb);
 544         error = xfs_rtalloc_query_range(mp, tp, &alow, &ahigh,
 545                         xfs_getfsmap_rtdev_rtbitmap_helper, info);
 546         if (error)
 547                 goto err;
 548
 549         /*
 550          * Report any gaps at the end of the rtbitmap by simulating a null
 551          * rmap starting at the block after the end of the query range.
 552          */
 553         info->last = true;
 554         ahigh.ar_startext = min(mp->m_sb.sb_rextents, ahigh.ar_startext);
 555
 556         error = xfs_getfsmap_rtdev_rtbitmap_helper(mp, tp, &ahigh, info);
 557         if (error)
 558                 goto err;
 559 err:
 560         xfs_iunlock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
 561         return error;
 562 }
 563 #endif /* CONFIG_XFS_RT */
 564
 565 static inline bool
 566 rmap_not_shareable(struct xfs_mount *mp, const struct xfs_rmap_irec *r)
 567 {
 568         if (!xfs_has_reflink(mp))
 569                 return true;
 570         if (XFS_RMAP_NON_INODE_OWNER(r->rm_owner))
 571                 return true;
 572         if (r->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK |
 573                            XFS_RMAP_UNWRITTEN))
 574                 return true;
 575         return false;
 576 }
 577
 578 /* Execute a getfsmap query against the regular data device. */
 579 STATIC int
 580 __xfs_getfsmap_datadev(
 581         struct xfs_trans                *tp,
 582         const struct xfs_fsmap          *keys,
 583         struct xfs_getfsmap_info        *info,
 584         int                             (*query_fn)(struct xfs_trans *,
 585                                                     struct xfs_getfsmap_info *,
 586                                                     struct xfs_btree_cur **,
 587                                                     void *),
 588         void                            *priv)
 589 {
 590         struct xfs_mount                *mp = tp->t_mountp;
 591         struct xfs_perag                *pag;
 592         struct xfs_btree_cur            *bt_cur = NULL;
 593         xfs_fsblock_t                   start_fsb;
 594         xfs_fsblock_t                   end_fsb;
 595         xfs_agnumber_t                  start_ag;
 596         xfs_agnumber_t                  end_ag;
 597         uint64_t                        eofs;
 598         int                             error = 0;
 599
 600         eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
 601         if (keys[0].fmr_physical >= eofs)
 602                 return 0;
 603         start_fsb = XFS_DADDR_TO_FSB(mp, keys[0].fmr_physical);
 604         end_fsb = XFS_DADDR_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
 605
 606         /*
 607          * Convert the fsmap low/high keys to AG based keys.  Initialize
 608          * low to the fsmap low key and max out the high key to the end
 609          * of the AG.
 610          */
 611         info->low.rm_offset = XFS_BB_TO_FSBT(mp, keys[0].fmr_offset);
 612         error = xfs_fsmap_owner_to_rmap(&info->low, &keys[0]);
 613         if (error)
 614                 return error;
 615         info->low.rm_blockcount = XFS_BB_TO_FSBT(mp, keys[0].fmr_length);
 616         xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);
 617
 618         /* Adjust the low key if we are continuing from where we left off. */
 619         if (info->low.rm_blockcount == 0) {
 620                 /* No previous record from which to continue */
 621         } else if (rmap_not_shareable(mp, &info->low)) {
 622                 /* Last record seen was an unshareable extent */
 623                 info->low.rm_owner = 0;
 624                 info->low.rm_offset = 0;
 625
 626                 start_fsb += info->low.rm_blockcount;
 627                 if (XFS_FSB_TO_DADDR(mp, start_fsb) >= eofs)
 628                         return 0;
 629         } else {
 630                 /* Last record seen was a shareable file data extent */
 631                 info->low.rm_offset += info->low.rm_blockcount;
 632         }
 633         info->low.rm_startblock = XFS_FSB_TO_AGBNO(mp, start_fsb);
 634
 635         info->high.rm_startblock = -1U;
 636         info->high.rm_owner = ULLONG_MAX;
 637         info->high.rm_offset = ULLONG_MAX;
 638         info->high.rm_blockcount = 0;
 639         info->high.rm_flags = XFS_RMAP_KEY_FLAGS | XFS_RMAP_REC_FLAGS;
 640
 641         start_ag = XFS_FSB_TO_AGNO(mp, start_fsb);
 642         end_ag = XFS_FSB_TO_AGNO(mp, end_fsb);
 643
 644         for_each_perag_range(mp, start_ag, end_ag, pag) {
 645                 /*
 646                  * Set the AG high key from the fsmap high key if this
 647                  * is the last AG that we're querying.
 648                  */
 649                 info->pag = pag;
 650                 if (pag->pag_agno == end_ag) {
 651                         info->high.rm_startblock = XFS_FSB_TO_AGBNO(mp,
 652                                         end_fsb);
 653                         info->high.rm_offset = XFS_BB_TO_FSBT(mp,
 654                                         keys[1].fmr_offset);
 655                         error = xfs_fsmap_owner_to_rmap(&info->high, &keys[1]);
 656                         if (error)
 657                                 break;
 658                         xfs_getfsmap_set_irec_flags(&info->high, &keys[1]);
 659                 }
 660
 661                 if (bt_cur) {
 662                         xfs_btree_del_cursor(bt_cur, XFS_BTREE_NOERROR);
 663                         bt_cur = NULL;
 664                         xfs_trans_brelse(tp, info->agf_bp);
 665                         info->agf_bp = NULL;
 666                 }
 667
 668                 error = xfs_alloc_read_agf(pag, tp, 0, &info->agf_bp);
 669                 if (error)
 670                         break;
 671
 672                 trace_xfs_fsmap_low_key(mp, info->dev, pag->pag_agno,
 673                                 &info->low);
 674                 trace_xfs_fsmap_high_key(mp, info->dev, pag->pag_agno,
 675                                 &info->high);
 676
 677                 error = query_fn(tp, info, &bt_cur, priv);
 678                 if (error)
 679                         break;
 680
 681                 /*
 682                  * Set the AG low key to the start of the AG prior to
 683                  * moving on to the next AG.
 684                  */
 685                 if (pag->pag_agno == start_ag)
 686                         memset(&info->low, 0, sizeof(info->low));
 687
 688                 /*
 689                  * If this is the last AG, report any gap at the end of it
 690                  * before we drop the reference to the perag when the loop
 691                  * terminates.
 692                  */
 693                 if (pag->pag_agno == end_ag) {
 694                         info->last = true;
 695                         error = query_fn(tp, info, &bt_cur, priv);
 696                         if (error)
 697                                 break;
 698                 }
 699                 info->pag = NULL;
 700         }
 701
 702         if (bt_cur)
 703                 xfs_btree_del_cursor(bt_cur, error < 0 ? XFS_BTREE_ERROR :
 704                                                          XFS_BTREE_NOERROR);
 705         if (info->agf_bp) {
 706                 xfs_trans_brelse(tp, info->agf_bp);
 707                 info->agf_bp = NULL;
 708         }
 709         if (info->pag) {
 710                 xfs_perag_rele(info->pag);
 711                 info->pag = NULL;
 712         } else if (pag) {
 713                 /* loop termination case */
 714                 xfs_perag_rele(pag);
 715         }
 716
 717         return error;
 718 }
 719
 720 /* Actually query the rmap btree. */
 721 STATIC int
 722 xfs_getfsmap_datadev_rmapbt_query(
 723         struct xfs_trans                *tp,
 724         struct xfs_getfsmap_info        *info,
 725         struct xfs_btree_cur            **curpp,
 726         void                            *priv)
 727 {
 728         /* Report any gap at the end of the last AG. */
 729         if (info->last)
 730                 return xfs_getfsmap_datadev_helper(*curpp, &info->high, info);
 731
 732         /* Allocate cursor for this AG and query_range it. */
 733         *curpp = xfs_rmapbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
 734                         info->pag);
 735         return xfs_rmap_query_range(*curpp, &info->low, &info->high,
 736                         xfs_getfsmap_datadev_helper, info);
 737 }
 738
 739 /* Execute a getfsmap query against the regular data device rmapbt. */
 740 STATIC int
 741 xfs_getfsmap_datadev_rmapbt(
 742         struct xfs_trans                *tp,
 743         const struct xfs_fsmap          *keys,
 744         struct xfs_getfsmap_info        *info)
 745 {
 746         info->missing_owner = XFS_FMR_OWN_FREE;
 747         return __xfs_getfsmap_datadev(tp, keys, info,
 748                         xfs_getfsmap_datadev_rmapbt_query, NULL);
 749 }
 750
 751 /* Actually query the bno btree. */
 752 STATIC int
 753 xfs_getfsmap_datadev_bnobt_query(
 754         struct xfs_trans                *tp,
 755         struct xfs_getfsmap_info        *info,
 756         struct xfs_btree_cur            **curpp,
 757         void                            *priv)
 758 {
 759         struct xfs_alloc_rec_incore     *key = priv;
 760
 761         /* Report any gap at the end of the last AG. */
 762         if (info->last)
 763                 return xfs_getfsmap_datadev_bnobt_helper(*curpp, &key[1], info);
 764
 765         /* Allocate cursor for this AG and query_range it. */
 766         *curpp = xfs_allocbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
 767                         info->pag, XFS_BTNUM_BNO);
 768         key->ar_startblock = info->low.rm_startblock;
 769         key[1].ar_startblock = info->high.rm_startblock;
 770         return xfs_alloc_query_range(*curpp, key, &key[1],
 771                         xfs_getfsmap_datadev_bnobt_helper, info);
 772 }
 773
 774 /* Execute a getfsmap query against the regular data device's bnobt. */
 775 STATIC int
 776 xfs_getfsmap_datadev_bnobt(
 777         struct xfs_trans                *tp,
 778         const struct xfs_fsmap          *keys,
 779         struct xfs_getfsmap_info        *info)
 780 {
 781         struct xfs_alloc_rec_incore     akeys[2];
 782
 783         memset(akeys, 0, sizeof(akeys));
 784         info->missing_owner = XFS_FMR_OWN_UNKNOWN;
 785         return __xfs_getfsmap_datadev(tp, keys, info,
 786                         xfs_getfsmap_datadev_bnobt_query, &akeys[0]);
 787 }
 788
 789 /* Do we recognize the device? */
 790 STATIC bool
 791 xfs_getfsmap_is_valid_device(
 792         struct xfs_mount        *mp,
 793         struct xfs_fsmap        *fm)
 794 {
 795         if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
 796             fm->fmr_device == new_encode_dev(mp->m_ddev_targp->bt_dev))
 797                 return true;
 798         if (mp->m_logdev_targp &&
 799             fm->fmr_device == new_encode_dev(mp->m_logdev_targp->bt_dev))
 800                 return true;
 801         if (mp->m_rtdev_targp &&
 802             fm->fmr_device == new_encode_dev(mp->m_rtdev_targp->bt_dev))
 803                 return true;
 804         return false;
 805 }
 806
 807 /* Ensure that the low key is less than the high key. */
 808 STATIC bool
 809 xfs_getfsmap_check_keys(
 810         struct xfs_fsmap                *low_key,
 811         struct xfs_fsmap                *high_key)
 812 {
 813         if (low_key->fmr_flags & (FMR_OF_SPECIAL_OWNER | FMR_OF_EXTENT_MAP)) {
 814                 if (low_key->fmr_offset)
 815                         return false;
 816         }
 817         if (high_key->fmr_flags != -1U &&
 818             (high_key->fmr_flags & (FMR_OF_SPECIAL_OWNER |
 819                                     FMR_OF_EXTENT_MAP))) {
 820                 if (high_key->fmr_offset && high_key->fmr_offset != -1ULL)
 821                         return false;
 822         }
 823         if (high_key->fmr_length && high_key->fmr_length != -1ULL)
 824                 return false;
 825
 826         if (low_key->fmr_device > high_key->fmr_device)
 827                 return false;
 828         if (low_key->fmr_device < high_key->fmr_device)
 829                 return true;
 830
 831         if (low_key->fmr_physical > high_key->fmr_physical)
 832                 return false;
 833         if (low_key->fmr_physical < high_key->fmr_physical)
 834                 return true;
 835
 836         if (low_key->fmr_owner > high_key->fmr_owner)
 837                 return false;
 838         if (low_key->fmr_owner < high_key->fmr_owner)
 839                 return true;
 840
 841         if (low_key->fmr_offset > high_key->fmr_offset)
 842                 return false;
 843         if (low_key->fmr_offset < high_key->fmr_offset)
 844                 return true;
 845
 846         return false;
 847 }
 848
 849 /*
 850  * There are only two devices if we didn't configure RT devices at build time.
 851  */
 852 #ifdef CONFIG_XFS_RT
 853 #define XFS_GETFSMAP_DEVS       3
 854 #else
 855 #define XFS_GETFSMAP_DEVS       2
 856 #endif /* CONFIG_XFS_RT */
 857
 858 /*
 859  * Get filesystem's extents as described in head, and format for output. Fills
 860  * in the supplied records array until there are no more reverse mappings to
 861  * return or head.fmh_entries == head.fmh_count.  In the second case, this
 862  * function returns -ECANCELED to indicate that more records would have been
 863  * returned.
 864  *
 865  * Key to Confusion
 866  * ----------------
 867  * There are multiple levels of keys and counters at work here:
 868  * xfs_fsmap_head.fmh_keys      -- low and high fsmap keys passed in;
 869  *                                 these reflect fs-wide sector addrs.
 870  * dkeys                        -- fmh_keys used to query each device;
 871  *                                 these are fmh_keys but w/ the low key
 872  *                                 bumped up by fmr_length.
 873  * xfs_getfsmap_info.next_daddr -- next disk addr we expect to see; this
 874  *                                 is how we detect gaps in the fsmap
 875                                    records and report them.
 876  * xfs_getfsmap_info.low/high   -- per-AG low/high keys computed from
 877  *                                 dkeys; used to query the metadata.
 878  */
 879 int
 880 xfs_getfsmap(
 881         struct xfs_mount                *mp,
 882         struct xfs_fsmap_head           *head,
 883         struct fsmap                    *fsmap_recs)
 884 {
 885         struct xfs_trans                *tp = NULL;
 886         struct xfs_fsmap                dkeys[2];       /* per-dev keys */
 887         struct xfs_getfsmap_dev         handlers[XFS_GETFSMAP_DEVS];
 888         struct xfs_getfsmap_info        info = { NULL };
 889         bool                            use_rmap;
 890         int                             i;
 891         int                             error = 0;
 892
 893         if (head->fmh_iflags & ~FMH_IF_VALID)
 894                 return -EINVAL;
 895         if (!xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[0]) ||
 896             !xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[1]))
 897                 return -EINVAL;
 898         if (!xfs_getfsmap_check_keys(&head->fmh_keys[0], &head->fmh_keys[1]))
 899                 return -EINVAL;
 900
 901         use_rmap = xfs_has_rmapbt(mp) &&
 902                    has_capability_noaudit(current, CAP_SYS_ADMIN);
 903         head->fmh_entries = 0;
 904
 905         /* Set up our device handlers. */
 906         memset(handlers, 0, sizeof(handlers));
 907         handlers[0].dev = new_encode_dev(mp->m_ddev_targp->bt_dev);
 908         if (use_rmap)
 909                 handlers[0].fn = xfs_getfsmap_datadev_rmapbt;
 910         else
 911                 handlers[0].fn = xfs_getfsmap_datadev_bnobt;
 912         if (mp->m_logdev_targp != mp->m_ddev_targp) {
 913                 handlers[1].dev = new_encode_dev(mp->m_logdev_targp->bt_dev);
 914                 handlers[1].fn = xfs_getfsmap_logdev;
 915         }
 916 #ifdef CONFIG_XFS_RT
 917         if (mp->m_rtdev_targp) {
 918                 handlers[2].dev = new_encode_dev(mp->m_rtdev_targp->bt_dev);
 919                 handlers[2].fn = xfs_getfsmap_rtdev_rtbitmap;
 920         }
 921 #endif /* CONFIG_XFS_RT */
 922
 923         xfs_sort(handlers, XFS_GETFSMAP_DEVS, sizeof(struct xfs_getfsmap_dev),
 924                         xfs_getfsmap_dev_compare);
 925
 926         /*
 927          * To continue where we left off, we allow userspace to use the
 928          * last mapping from a previous call as the low key of the next.
 929          * This is identified by a non-zero length in the low key. We
 930          * have to increment the low key in this scenario to ensure we
 931          * don't return the same mapping again, and instead return the
 932          * very next mapping.
 933          *
 934          * If the low key mapping refers to file data, the same physical
 935          * blocks could be mapped to several other files/offsets.
 936          * According to rmapbt record ordering, the minimal next
 937          * possible record for the block range is the next starting
 938          * offset in the same inode. Therefore, each fsmap backend bumps
 939          * the file offset to continue the search appropriately.  For
 940          * all other low key mapping types (attr blocks, metadata), each
 941          * fsmap backend bumps the physical offset as there can be no
 942          * other mapping for the same physical block range.
 943          */
 944         dkeys[0] = head->fmh_keys[0];
 945         memset(&dkeys[1], 0xFF, sizeof(struct xfs_fsmap));
 946
 947         info.next_daddr = head->fmh_keys[0].fmr_physical +
 948                           head->fmh_keys[0].fmr_length;
 949         info.fsmap_recs = fsmap_recs;
 950         info.head = head;
 951
 952         /* For each device we support... */
 953         for (i = 0; i < XFS_GETFSMAP_DEVS; i++) {
 954                 /* Is this device within the range the user asked for? */
 955                 if (!handlers[i].fn)
 956                         continue;
 957                 if (head->fmh_keys[0].fmr_device > handlers[i].dev)
 958                         continue;
 959                 if (head->fmh_keys[1].fmr_device < handlers[i].dev)
 960                         break;
 961
 962                 /*
 963                  * If this device number matches the high key, we have
 964                  * to pass the high key to the handler to limit the
 965                  * query results.  If the device number exceeds the
 966                  * low key, zero out the low key so that we get
 967                  * everything from the beginning.
 968                  */
 969                 if (handlers[i].dev == head->fmh_keys[1].fmr_device)
 970                         dkeys[1] = head->fmh_keys[1];
 971                 if (handlers[i].dev > head->fmh_keys[0].fmr_device)
 972                         memset(&dkeys[0], 0, sizeof(struct xfs_fsmap));
 973
 974                 /*
 975                  * Grab an empty transaction so that we can use its recursive
 976                  * buffer locking abilities to detect cycles in the rmapbt
 977                  * without deadlocking.
 978                  */
 979                 error = xfs_trans_alloc_empty(mp, &tp);
 980                 if (error)
 981                         break;
 982
 983                 info.dev = handlers[i].dev;
 984                 info.last = false;
 985                 info.pag = NULL;
 986                 info.low_daddr = -1ULL;
 987                 info.low.rm_blockcount = 0;
 988                 error = handlers[i].fn(tp, dkeys, &info);
 989                 if (error)
 990                         break;
 991                 xfs_trans_cancel(tp);
 992                 tp = NULL;
 993                 info.next_daddr = 0;
 994         }
 995
 996         if (tp)
 997                 xfs_trans_cancel(tp);
 998         head->fmh_oflags = FMH_OF_DEV_T;
 999         return error;
1000 }