fs/xfs/xfs_utils.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_bit.h"
  22 #include "xfs_log.h"
  23 #include "xfs_inum.h"
  24 #include "xfs_trans.h"
  25 #include "xfs_sb.h"
  26 #include "xfs_ag.h"
  27 #include "xfs_dir2.h"
  28 #include "xfs_dmapi.h"
  29 #include "xfs_mount.h"
  30 #include "xfs_bmap_btree.h"
  31 #include "xfs_dir2_sf.h"
  32 #include "xfs_attr_sf.h"
  33 #include "xfs_dinode.h"
  34 #include "xfs_inode.h"
  35 #include "xfs_inode_item.h"
  36 #include "xfs_bmap.h"
  37 #include "xfs_error.h"
  38 #include "xfs_quota.h"
  39 #include "xfs_rw.h"
  40 #include "xfs_itable.h"
  41 #include "xfs_utils.h"
  42
  43 /*
  44  * xfs_get_dir_entry is used to get a reference to an inode given
  45  * its parent directory inode and the name of the file.  It does
  46  * not lock the child inode, and it unlocks the directory before
  47  * returning.  The directory's generation number is returned for
  48  * use by a later call to xfs_lock_dir_and_entry.
  49  */
  50 int
  51 xfs_get_dir_entry(
  52         bhv_vname_t     *dentry,
  53         xfs_inode_t     **ipp)
  54 {
  55         bhv_vnode_t     *vp;
  56
  57         vp = VNAME_TO_VNODE(dentry);
  58
  59         *ipp = xfs_vtoi(vp);
  60         if (!*ipp)
  61                 return XFS_ERROR(ENOENT);
  62         VN_HOLD(vp);
  63         return 0;
  64 }
  65
  66 int
  67 xfs_dir_lookup_int(
  68         xfs_inode_t     *dp,
  69         uint            lock_mode,
  70         bhv_vname_t     *dentry,
  71         xfs_ino_t       *inum,
  72         xfs_inode_t     **ipp)
  73 {
  74         int             error;
  75
  76         xfs_itrace_entry(dp);
  77
  78         error = xfs_dir_lookup(NULL, dp, VNAME(dentry), VNAMELEN(dentry), inum);
  79         if (!error) {
  80                 /*
  81                  * Unlock the directory. We do this because we can't
  82                  * hold the directory lock while doing the vn_get()
  83                  * in xfs_iget().  Doing so could cause us to hold
  84                  * a lock while waiting for the inode to finish
  85                  * being inactive while it's waiting for a log
  86                  * reservation in the inactive routine.
  87                  */
  88                 xfs_iunlock(dp, lock_mode);
  89                 error = xfs_iget(dp->i_mount, NULL, *inum, 0, 0, ipp, 0);
  90                 xfs_ilock(dp, lock_mode);
  91
  92                 if (error) {
  93                         *ipp = NULL;
  94                 } else if ((*ipp)->i_d.di_mode == 0) {
  95                         /*
  96                          * The inode has been freed.  Something is
  97                          * wrong so just get out of here.
  98                          */
  99                         xfs_iunlock(dp, lock_mode);
 100                         xfs_iput_new(*ipp, 0);
 101                         *ipp = NULL;
 102                         xfs_ilock(dp, lock_mode);
 103                         error = XFS_ERROR(ENOENT);
 104                 }
 105         }
 106         return error;
 107 }
 108
 109 /*
 110  * Allocates a new inode from disk and return a pointer to the
 111  * incore copy. This routine will internally commit the current
 112  * transaction and allocate a new one if the Space Manager needed
 113  * to do an allocation to replenish the inode free-list.
 114  *
 115  * This routine is designed to be called from xfs_create and
 116  * xfs_create_dir.
 117  *
 118  */
 119 int
 120 xfs_dir_ialloc(
 121         xfs_trans_t     **tpp,          /* input: current transaction;
 122                                            output: may be a new transaction. */
 123         xfs_inode_t     *dp,            /* directory within whose allocate
 124                                            the inode. */
 125         mode_t          mode,
 126         xfs_nlink_t     nlink,
 127         xfs_dev_t       rdev,
 128         cred_t          *credp,
 129         prid_t          prid,           /* project id */
 130         int             okalloc,        /* ok to allocate new space */
 131         xfs_inode_t     **ipp,          /* pointer to inode; it will be
 132                                            locked. */
 133         int             *committed)
 134
 135 {
 136         xfs_trans_t     *tp;
 137         xfs_trans_t     *ntp;
 138         xfs_inode_t     *ip;
 139         xfs_buf_t       *ialloc_context = NULL;
 140         boolean_t       call_again = B_FALSE;
 141         int             code;
 142         uint            log_res;
 143         uint            log_count;
 144         void            *dqinfo;
 145         uint            tflags;
 146
 147         tp = *tpp;
 148         ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 149
 150         /*
 151          * xfs_ialloc will return a pointer to an incore inode if
 152          * the Space Manager has an available inode on the free
 153          * list. Otherwise, it will do an allocation and replenish
 154          * the freelist.  Since we can only do one allocation per
 155          * transaction without deadlocks, we will need to commit the
 156          * current transaction and start a new one.  We will then
 157          * need to call xfs_ialloc again to get the inode.
 158          *
 159          * If xfs_ialloc did an allocation to replenish the freelist,
 160          * it returns the bp containing the head of the freelist as
 161          * ialloc_context. We will hold a lock on it across the
 162          * transaction commit so that no other process can steal
 163          * the inode(s) that we've just allocated.
 164          */
 165         code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid, okalloc,
 166                           &ialloc_context, &call_again, &ip);
 167
 168         /*
 169          * Return an error if we were unable to allocate a new inode.
 170          * This should only happen if we run out of space on disk or
 171          * encounter a disk error.
 172          */
 173         if (code) {
 174                 *ipp = NULL;
 175                 return code;
 176         }
 177         if (!call_again && (ip == NULL)) {
 178                 *ipp = NULL;
 179                 return XFS_ERROR(ENOSPC);
 180         }
 181
 182         /*
 183          * If call_again is set, then we were unable to get an
 184          * inode in one operation.  We need to commit the current
 185          * transaction and call xfs_ialloc() again.  It is guaranteed
 186          * to succeed the second time.
 187          */
 188         if (call_again) {
 189
 190                 /*
 191                  * Normally, xfs_trans_commit releases all the locks.
 192                  * We call bhold to hang on to the ialloc_context across
 193                  * the commit.  Holding this buffer prevents any other
 194                  * processes from doing any allocations in this
 195                  * allocation group.
 196                  */
 197                 xfs_trans_bhold(tp, ialloc_context);
 198                 /*
 199                  * Save the log reservation so we can use
 200                  * them in the next transaction.
 201                  */
 202                 log_res = xfs_trans_get_log_res(tp);
 203                 log_count = xfs_trans_get_log_count(tp);
 204
 205                 /*
 206                  * We want the quota changes to be associated with the next
 207                  * transaction, NOT this one. So, detach the dqinfo from this
 208                  * and attach it to the next transaction.
 209                  */
 210                 dqinfo = NULL;
 211                 tflags = 0;
 212                 if (tp->t_dqinfo) {
 213                         dqinfo = (void *)tp->t_dqinfo;
 214                         tp->t_dqinfo = NULL;
 215                         tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
 216                         tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
 217                 }
 218
 219                 ntp = xfs_trans_dup(tp);
 220                 code = xfs_trans_commit(tp, 0);
 221                 tp = ntp;
 222                 if (committed != NULL) {
 223                         *committed = 1;
 224                 }
 225                 /*
 226                  * If we get an error during the commit processing,
 227                  * release the buffer that is still held and return
 228                  * to the caller.
 229                  */
 230                 if (code) {
 231                         xfs_buf_relse(ialloc_context);
 232                         if (dqinfo) {
 233                                 tp->t_dqinfo = dqinfo;
 234                                 XFS_TRANS_FREE_DQINFO(tp->t_mountp, tp);
 235                         }
 236                         *tpp = ntp;
 237                         *ipp = NULL;
 238                         return code;
 239                 }
 240                 code = xfs_trans_reserve(tp, 0, log_res, 0,
 241                                          XFS_TRANS_PERM_LOG_RES, log_count);
 242                 /*
 243                  * Re-attach the quota info that we detached from prev trx.
 244                  */
 245                 if (dqinfo) {
 246                         tp->t_dqinfo = dqinfo;
 247                         tp->t_flags |= tflags;
 248                 }
 249
 250                 if (code) {
 251                         xfs_buf_relse(ialloc_context);
 252                         *tpp = ntp;
 253                         *ipp = NULL;
 254                         return code;
 255                 }
 256                 xfs_trans_bjoin(tp, ialloc_context);
 257
 258                 /*
 259                  * Call ialloc again. Since we've locked out all
 260                  * other allocations in this allocation group,
 261                  * this call should always succeed.
 262                  */
 263                 code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid,
 264                                   okalloc, &ialloc_context, &call_again, &ip);
 265
 266                 /*
 267                  * If we get an error at this point, return to the caller
 268                  * so that the current transaction can be aborted.
 269                  */
 270                 if (code) {
 271                         *tpp = tp;
 272                         *ipp = NULL;
 273                         return code;
 274                 }
 275                 ASSERT ((!call_again) && (ip != NULL));
 276
 277         } else {
 278                 if (committed != NULL) {
 279                         *committed = 0;
 280                 }
 281         }
 282
 283         *ipp = ip;
 284         *tpp = tp;
 285
 286         return 0;
 287 }
 288
 289 /*
 290  * Decrement the link count on an inode & log the change.
 291  * If this causes the link count to go to zero, initiate the
 292  * logging activity required to truncate a file.
 293  */
 294 int                             /* error */
 295 xfs_droplink(
 296         xfs_trans_t *tp,
 297         xfs_inode_t *ip)
 298 {
 299         int     error;
 300
 301         xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
 302
 303         ASSERT (ip->i_d.di_nlink > 0);
 304         ip->i_d.di_nlink--;
 305         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 306
 307         error = 0;
 308         if (ip->i_d.di_nlink == 0) {
 309                 /*
 310                  * We're dropping the last link to this file.
 311                  * Move the on-disk inode to the AGI unlinked list.
 312                  * From xfs_inactive() we will pull the inode from
 313                  * the list and free it.
 314                  */
 315                 error = xfs_iunlink(tp, ip);
 316         }
 317         return error;
 318 }
 319
 320 /*
 321  * This gets called when the inode's version needs to be changed from 1 to 2.
 322  * Currently this happens when the nlink field overflows the old 16-bit value
 323  * or when chproj is called to change the project for the first time.
 324  * As a side effect the superblock version will also get rev'd
 325  * to contain the NLINK bit.
 326  */
 327 void
 328 xfs_bump_ino_vers2(
 329         xfs_trans_t     *tp,
 330         xfs_inode_t     *ip)
 331 {
 332         xfs_mount_t     *mp;
 333
 334         ASSERT(ismrlocked (&ip->i_lock, MR_UPDATE));
 335         ASSERT(ip->i_d.di_version == XFS_DINODE_VERSION_1);
 336
 337         ip->i_d.di_version = XFS_DINODE_VERSION_2;
 338         ip->i_d.di_onlink = 0;
 339         memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
 340         mp = tp->t_mountp;
 341         if (!XFS_SB_VERSION_HASNLINK(&mp->m_sb)) {
 342                 spin_lock(&mp->m_sb_lock);
 343                 if (!XFS_SB_VERSION_HASNLINK(&mp->m_sb)) {
 344                         XFS_SB_VERSION_ADDNLINK(&mp->m_sb);
 345                         spin_unlock(&mp->m_sb_lock);
 346                         xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
 347                 } else {
 348                         spin_unlock(&mp->m_sb_lock);
 349                 }
 350         }
 351         /* Caller must log the inode */
 352 }
 353
 354 /*
 355  * Increment the link count on an inode & log the change.
 356  */
 357 int
 358 xfs_bumplink(
 359         xfs_trans_t *tp,
 360         xfs_inode_t *ip)
 361 {
 362         if (ip->i_d.di_nlink >= XFS_MAXLINK)
 363                 return XFS_ERROR(EMLINK);
 364         xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
 365
 366         ASSERT(ip->i_d.di_nlink > 0);
 367         ip->i_d.di_nlink++;
 368         if ((ip->i_d.di_version == XFS_DINODE_VERSION_1) &&
 369             (ip->i_d.di_nlink > XFS_MAXLINK_1)) {
 370                 /*
 371                  * The inode has increased its number of links beyond
 372                  * what can fit in an old format inode.  It now needs
 373                  * to be converted to a version 2 inode with a 32 bit
 374                  * link count.  If this is the first inode in the file
 375                  * system to do this, then we need to bump the superblock
 376                  * version number as well.
 377                  */
 378                 xfs_bump_ino_vers2(tp, ip);
 379         }
 380
 381         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 382         return 0;
 383 }
 384
 385 /*
 386  * Try to truncate the given file to 0 length.  Currently called
 387  * only out of xfs_remove when it has to truncate a file to free
 388  * up space for the remove to proceed.
 389  */
 390 int
 391 xfs_truncate_file(
 392         xfs_mount_t     *mp,
 393         xfs_inode_t     *ip)
 394 {
 395         xfs_trans_t     *tp;
 396         int             error;
 397
 398 #ifdef QUOTADEBUG
 399         /*
 400          * This is called to truncate the quotainodes too.
 401          */
 402         if (XFS_IS_UQUOTA_ON(mp)) {
 403                 if (ip->i_ino != mp->m_sb.sb_uquotino)
 404                         ASSERT(ip->i_udquot);
 405         }
 406         if (XFS_IS_OQUOTA_ON(mp)) {
 407                 if (ip->i_ino != mp->m_sb.sb_gquotino)
 408                         ASSERT(ip->i_gdquot);
 409         }
 410 #endif
 411         /*
 412          * Make the call to xfs_itruncate_start before starting the
 413          * transaction, because we cannot make the call while we're
 414          * in a transaction.
 415          */
 416         xfs_ilock(ip, XFS_IOLOCK_EXCL);
 417         error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, (xfs_fsize_t)0);
 418         if (error) {
 419                 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 420                 return error;
 421         }
 422
 423         tp = xfs_trans_alloc(mp, XFS_TRANS_TRUNCATE_FILE);
 424         if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
 425                                       XFS_TRANS_PERM_LOG_RES,
 426                                       XFS_ITRUNCATE_LOG_COUNT))) {
 427                 xfs_trans_cancel(tp, 0);
 428                 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 429                 return error;
 430         }
 431
 432         /*
 433          * Follow the normal truncate locking protocol.  Since we
 434          * hold the inode in the transaction, we know that it's number
 435          * of references will stay constant.
 436          */
 437         xfs_ilock(ip, XFS_ILOCK_EXCL);
 438         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 439         xfs_trans_ihold(tp, ip);
 440         /*
 441          * Signal a sync xaction.  The only case where that isn't
 442          * the case is if we're truncating an already unlinked file
 443          * on a wsync fs.  In that case, we know the blocks can't
 444          * reappear in the file because the links to file are
 445          * permanently toast.  Currently, we're always going to
 446          * want a sync transaction because this code is being
 447          * called from places where nlink is guaranteed to be 1
 448          * but I'm leaving the tests in to protect against future
 449          * changes -- rcc.
 450          */
 451         error = xfs_itruncate_finish(&tp, ip, (xfs_fsize_t)0,
 452                                      XFS_DATA_FORK,
 453                                      ((ip->i_d.di_nlink != 0 ||
 454                                        !(mp->m_flags & XFS_MOUNT_WSYNC))
 455                                       ? 1 : 0));
 456         if (error) {
 457                 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
 458                                  XFS_TRANS_ABORT);
 459         } else {
 460                 xfs_ichgtime(ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 461                 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 462         }
 463         xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 464
 465         return error;
 466 }