fs/xfs/xfs_filestream.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2006-2007 Silicon Graphics, Inc.
   4  * Copyright (c) 2014 Christoph Hellwig.
   5  * All Rights Reserved.
   6  */
   7 #include "xfs.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_bmap.h"
  15 #include "xfs_alloc.h"
  16 #include "xfs_mru_cache.h"
  17 #include "xfs_trace.h"
  18 #include "xfs_ag.h"
  19 #include "xfs_ag_resv.h"
  20 #include "xfs_trans.h"
  21 #include "xfs_filestream.h"
  22
  23 struct xfs_fstrm_item {
  24         struct xfs_mru_cache_elem       mru;
  25         xfs_agnumber_t                  ag; /* AG in use for this directory */
  26 };
  27
  28 enum xfs_fstrm_alloc {
  29         XFS_PICK_USERDATA = 1,
  30         XFS_PICK_LOWSPACE = 2,
  31 };
  32
  33 /*
  34  * Allocation group filestream associations are tracked with per-ag atomic
  35  * counters.  These counters allow xfs_filestream_pick_ag() to tell whether a
  36  * particular AG already has active filestreams associated with it.
  37  */
  38 int
  39 xfs_filestream_peek_ag(
  40         xfs_mount_t     *mp,
  41         xfs_agnumber_t  agno)
  42 {
  43         struct xfs_perag *pag;
  44         int             ret;
  45
  46         pag = xfs_perag_get(mp, agno);
  47         ret = atomic_read(&pag->pagf_fstrms);
  48         xfs_perag_put(pag);
  49         return ret;
  50 }
  51
  52 static int
  53 xfs_filestream_get_ag(
  54         xfs_mount_t     *mp,
  55         xfs_agnumber_t  agno)
  56 {
  57         struct xfs_perag *pag;
  58         int             ret;
  59
  60         pag = xfs_perag_get(mp, agno);
  61         ret = atomic_inc_return(&pag->pagf_fstrms);
  62         xfs_perag_put(pag);
  63         return ret;
  64 }
  65
  66 static void
  67 xfs_filestream_put_ag(
  68         xfs_mount_t     *mp,
  69         xfs_agnumber_t  agno)
  70 {
  71         struct xfs_perag *pag;
  72
  73         pag = xfs_perag_get(mp, agno);
  74         atomic_dec(&pag->pagf_fstrms);
  75         xfs_perag_put(pag);
  76 }
  77
  78 static void
  79 xfs_fstrm_free_func(
  80         void                    *data,
  81         struct xfs_mru_cache_elem *mru)
  82 {
  83         struct xfs_mount        *mp = data;
  84         struct xfs_fstrm_item   *item =
  85                 container_of(mru, struct xfs_fstrm_item, mru);
  86
  87         xfs_filestream_put_ag(mp, item->ag);
  88         trace_xfs_filestream_free(mp, mru->key, item->ag);
  89
  90         kmem_free(item);
  91 }
  92
  93 /*
  94  * Scan the AGs starting at startag looking for an AG that isn't in use and has
  95  * at least minlen blocks free.
  96  */
  97 static int
  98 xfs_filestream_pick_ag(
  99         struct xfs_inode        *ip,
 100         xfs_agnumber_t          startag,
 101         xfs_agnumber_t          *agp,
 102         int                     flags,
 103         xfs_extlen_t            minlen)
 104 {
 105         struct xfs_mount        *mp = ip->i_mount;
 106         struct xfs_fstrm_item   *item;
 107         struct xfs_perag        *pag;
 108         xfs_extlen_t            longest, free = 0, minfree, maxfree = 0;
 109         xfs_agnumber_t          ag, max_ag = NULLAGNUMBER;
 110         int                     err, trylock, nscan;
 111
 112         ASSERT(S_ISDIR(VFS_I(ip)->i_mode));
 113
 114         /* 2% of an AG's blocks must be free for it to be chosen. */
 115         minfree = mp->m_sb.sb_agblocks / 50;
 116
 117         ag = startag;
 118         *agp = NULLAGNUMBER;
 119
 120         /* For the first pass, don't sleep trying to init the per-AG. */
 121         trylock = XFS_ALLOC_FLAG_TRYLOCK;
 122
 123         for (nscan = 0; 1; nscan++) {
 124                 trace_xfs_filestream_scan(mp, ip->i_ino, ag);
 125
 126                 pag = xfs_perag_get(mp, ag);
 127
 128                 if (!pag->pagf_init) {
 129                         err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
 130                         if (err) {
 131                                 xfs_perag_put(pag);
 132                                 if (err != -EAGAIN)
 133                                         return err;
 134                                 /* Couldn't lock the AGF, skip this AG. */
 135                                 continue;
 136                         }
 137                 }
 138
 139                 /* Keep track of the AG with the most free blocks. */
 140                 if (pag->pagf_freeblks > maxfree) {
 141                         maxfree = pag->pagf_freeblks;
 142                         max_ag = ag;
 143                 }
 144
 145                 /*
 146                  * The AG reference count does two things: it enforces mutual
 147                  * exclusion when examining the suitability of an AG in this
 148                  * loop, and it guards against two filestreams being established
 149                  * in the same AG as each other.
 150                  */
 151                 if (xfs_filestream_get_ag(mp, ag) > 1) {
 152                         xfs_filestream_put_ag(mp, ag);
 153                         goto next_ag;
 154                 }
 155
 156                 longest = xfs_alloc_longest_free_extent(pag,
 157                                 xfs_alloc_min_freelist(mp, pag),
 158                                 xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE));
 159                 if (((minlen && longest >= minlen) ||
 160                      (!minlen && pag->pagf_freeblks >= minfree)) &&
 161                     (!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||
 162                      (flags & XFS_PICK_LOWSPACE))) {
 163
 164                         /* Break out, retaining the reference on the AG. */
 165                         free = pag->pagf_freeblks;
 166                         xfs_perag_put(pag);
 167                         *agp = ag;
 168                         break;
 169                 }
 170
 171                 /* Drop the reference on this AG, it's not usable. */
 172                 xfs_filestream_put_ag(mp, ag);
 173 next_ag:
 174                 xfs_perag_put(pag);
 175                 /* Move to the next AG, wrapping to AG 0 if necessary. */
 176                 if (++ag >= mp->m_sb.sb_agcount)
 177                         ag = 0;
 178
 179                 /* If a full pass of the AGs hasn't been done yet, continue. */
 180                 if (ag != startag)
 181                         continue;
 182
 183                 /* Allow sleeping in xfs_alloc_pagf_init() on the 2nd pass. */
 184                 if (trylock != 0) {
 185                         trylock = 0;
 186                         continue;
 187                 }
 188
 189                 /* Finally, if lowspace wasn't set, set it for the 3rd pass. */
 190                 if (!(flags & XFS_PICK_LOWSPACE)) {
 191                         flags |= XFS_PICK_LOWSPACE;
 192                         continue;
 193                 }
 194
 195                 /*
 196                  * Take the AG with the most free space, regardless of whether
 197                  * it's already in use by another filestream.
 198                  */
 199                 if (max_ag != NULLAGNUMBER) {
 200                         xfs_filestream_get_ag(mp, max_ag);
 201                         free = maxfree;
 202                         *agp = max_ag;
 203                         break;
 204                 }
 205
 206                 /* take AG 0 if none matched */
 207                 trace_xfs_filestream_pick(ip, *agp, free, nscan);
 208                 *agp = 0;
 209                 return 0;
 210         }
 211
 212         trace_xfs_filestream_pick(ip, *agp, free, nscan);
 213
 214         if (*agp == NULLAGNUMBER)
 215                 return 0;
 216
 217         err = -ENOMEM;
 218         item = kmem_alloc(sizeof(*item), KM_MAYFAIL);
 219         if (!item)
 220                 goto out_put_ag;
 221
 222         item->ag = *agp;
 223
 224         err = xfs_mru_cache_insert(mp->m_filestream, ip->i_ino, &item->mru);
 225         if (err) {
 226                 if (err == -EEXIST)
 227                         err = 0;
 228                 goto out_free_item;
 229         }
 230
 231         return 0;
 232
 233 out_free_item:
 234         kmem_free(item);
 235 out_put_ag:
 236         xfs_filestream_put_ag(mp, *agp);
 237         return err;
 238 }
 239
 240 static struct xfs_inode *
 241 xfs_filestream_get_parent(
 242         struct xfs_inode        *ip)
 243 {
 244         struct inode            *inode = VFS_I(ip), *dir = NULL;
 245         struct dentry           *dentry, *parent;
 246
 247         dentry = d_find_alias(inode);
 248         if (!dentry)
 249                 goto out;
 250
 251         parent = dget_parent(dentry);
 252         if (!parent)
 253                 goto out_dput;
 254
 255         dir = igrab(d_inode(parent));
 256         dput(parent);
 257
 258 out_dput:
 259         dput(dentry);
 260 out:
 261         return dir ? XFS_I(dir) : NULL;
 262 }
 263
 264 /*
 265  * Find the right allocation group for a file, either by finding an
 266  * existing file stream or creating a new one.
 267  *
 268  * Returns NULLAGNUMBER in case of an error.
 269  */
 270 xfs_agnumber_t
 271 xfs_filestream_lookup_ag(
 272         struct xfs_inode        *ip)
 273 {
 274         struct xfs_mount        *mp = ip->i_mount;
 275         struct xfs_inode        *pip = NULL;
 276         xfs_agnumber_t          startag, ag = NULLAGNUMBER;
 277         struct xfs_mru_cache_elem *mru;
 278
 279         ASSERT(S_ISREG(VFS_I(ip)->i_mode));
 280
 281         pip = xfs_filestream_get_parent(ip);
 282         if (!pip)
 283                 return NULLAGNUMBER;
 284
 285         mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
 286         if (mru) {
 287                 ag = container_of(mru, struct xfs_fstrm_item, mru)->ag;
 288                 xfs_mru_cache_done(mp->m_filestream);
 289
 290                 trace_xfs_filestream_lookup(mp, ip->i_ino, ag);
 291                 goto out;
 292         }
 293
 294         /*
 295          * Set the starting AG using the rotor for inode32, otherwise
 296          * use the directory inode's AG.
 297          */
 298         if (xfs_is_inode32(mp)) {
 299                 xfs_agnumber_t   rotorstep = xfs_rotorstep;
 300                 startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
 301                 mp->m_agfrotor = (mp->m_agfrotor + 1) %
 302                                  (mp->m_sb.sb_agcount * rotorstep);
 303         } else
 304                 startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
 305
 306         if (xfs_filestream_pick_ag(pip, startag, &ag, 0, 0))
 307                 ag = NULLAGNUMBER;
 308 out:
 309         xfs_irele(pip);
 310         return ag;
 311 }
 312
 313 /*
 314  * Pick a new allocation group for the current file and its file stream.
 315  *
 316  * This is called when the allocator can't find a suitable extent in the
 317  * current AG, and we have to move the stream into a new AG with more space.
 318  */
 319 int
 320 xfs_filestream_new_ag(
 321         struct xfs_bmalloca     *ap,
 322         xfs_agnumber_t          *agp)
 323 {
 324         struct xfs_inode        *ip = ap->ip, *pip;
 325         struct xfs_mount        *mp = ip->i_mount;
 326         xfs_extlen_t            minlen = ap->length;
 327         xfs_agnumber_t          startag = 0;
 328         int                     flags = 0;
 329         int                     err = 0;
 330         struct xfs_mru_cache_elem *mru;
 331
 332         *agp = NULLAGNUMBER;
 333
 334         pip = xfs_filestream_get_parent(ip);
 335         if (!pip)
 336                 goto exit;
 337
 338         mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
 339         if (mru) {
 340                 struct xfs_fstrm_item *item =
 341                         container_of(mru, struct xfs_fstrm_item, mru);
 342                 startag = (item->ag + 1) % mp->m_sb.sb_agcount;
 343         }
 344
 345         if (ap->datatype & XFS_ALLOC_USERDATA)
 346                 flags |= XFS_PICK_USERDATA;
 347         if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
 348                 flags |= XFS_PICK_LOWSPACE;
 349
 350         err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
 351
 352         /*
 353          * Only free the item here so we skip over the old AG earlier.
 354          */
 355         if (mru)
 356                 xfs_fstrm_free_func(mp, mru);
 357
 358         xfs_irele(pip);
 359 exit:
 360         if (*agp == NULLAGNUMBER)
 361                 *agp = 0;
 362         return err;
 363 }
 364
 365 void
 366 xfs_filestream_deassociate(
 367         struct xfs_inode        *ip)
 368 {
 369         xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
 370 }
 371
 372 int
 373 xfs_filestream_mount(
 374         xfs_mount_t     *mp)
 375 {
 376         /*
 377          * The filestream timer tunable is currently fixed within the range of
 378          * one second to four minutes, with five seconds being the default.  The
 379          * group count is somewhat arbitrary, but it'd be nice to adhere to the
 380          * timer tunable to within about 10 percent.  This requires at least 10
 381          * groups.
 382          */
 383         return xfs_mru_cache_create(&mp->m_filestream, mp,
 384                         xfs_fstrm_centisecs * 10, 10, xfs_fstrm_free_func);
 385 }
 386
 387 void
 388 xfs_filestream_unmount(
 389         xfs_mount_t     *mp)
 390 {
 391         xfs_mru_cache_destroy(mp->m_filestream);
 392 }