fs/xfs/xfs_utils.c

   1 /*
   2  * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32
  33 #include "xfs.h"
  34 #include "xfs_macros.h"
  35 #include "xfs_types.h"
  36 #include "xfs_inum.h"
  37 #include "xfs_log.h"
  38 #include "xfs_trans.h"
  39 #include "xfs_sb.h"
  40 #include "xfs_dir.h"
  41 #include "xfs_dir2.h"
  42 #include "xfs_dmapi.h"
  43 #include "xfs_mount.h"
  44 #include "xfs_bmap_btree.h"
  45 #include "xfs_attr_sf.h"
  46 #include "xfs_dir_sf.h"
  47 #include "xfs_dir2_sf.h"
  48 #include "xfs_dinode.h"
  49 #include "xfs_inode_item.h"
  50 #include "xfs_inode.h"
  51 #include "xfs_bmap.h"
  52 #include "xfs_error.h"
  53 #include "xfs_quota.h"
  54 #include "xfs_rw.h"
  55 #include "xfs_itable.h"
  56 #include "xfs_utils.h"
  57
  58 /*
  59  * xfs_get_dir_entry is used to get a reference to an inode given
  60  * its parent directory inode and the name of the file.  It does
  61  * not lock the child inode, and it unlocks the directory before
  62  * returning.  The directory's generation number is returned for
  63  * use by a later call to xfs_lock_dir_and_entry.
  64  */
  65 int
  66 xfs_get_dir_entry(
  67         vname_t         *dentry,
  68         xfs_inode_t     **ipp)
  69 {
  70         vnode_t         *vp;
  71         bhv_desc_t      *bdp;
  72
  73         vp = VNAME_TO_VNODE(dentry);
  74         bdp = vn_bhv_lookup_unlocked(VN_BHV_HEAD(vp), &xfs_vnodeops);
  75         if (!bdp) {
  76                 *ipp = NULL;
  77                 return XFS_ERROR(ENOENT);
  78         }
  79         VN_HOLD(vp);
  80         *ipp = XFS_BHVTOI(bdp);
  81         return 0;
  82 }
  83
  84 int
  85 xfs_dir_lookup_int(
  86         bhv_desc_t      *dir_bdp,
  87         uint            lock_mode,
  88         vname_t         *dentry,
  89         xfs_ino_t       *inum,
  90         xfs_inode_t     **ipp)
  91 {
  92         vnode_t         *dir_vp;
  93         xfs_inode_t     *dp;
  94         int             error;
  95
  96         dir_vp = BHV_TO_VNODE(dir_bdp);
  97         vn_trace_entry(dir_vp, __FUNCTION__, (inst_t *)__return_address);
  98
  99         dp = XFS_BHVTOI(dir_bdp);
 100
 101         error = XFS_DIR_LOOKUP(dp->i_mount, NULL, dp,
 102                                 VNAME(dentry), VNAMELEN(dentry), inum);
 103         if (!error) {
 104                 /*
 105                  * Unlock the directory. We do this because we can't
 106                  * hold the directory lock while doing the vn_get()
 107                  * in xfs_iget().  Doing so could cause us to hold
 108                  * a lock while waiting for the inode to finish
 109                  * being inactive while it's waiting for a log
 110                  * reservation in the inactive routine.
 111                  */
 112                 xfs_iunlock(dp, lock_mode);
 113                 error = xfs_iget(dp->i_mount, NULL, *inum, 0, 0, ipp, 0);
 114                 xfs_ilock(dp, lock_mode);
 115
 116                 if (error) {
 117                         *ipp = NULL;
 118                 } else if ((*ipp)->i_d.di_mode == 0) {
 119                         /*
 120                          * The inode has been freed.  Something is
 121                          * wrong so just get out of here.
 122                          */
 123                         xfs_iunlock(dp, lock_mode);
 124                         xfs_iput_new(*ipp, 0);
 125                         *ipp = NULL;
 126                         xfs_ilock(dp, lock_mode);
 127                         error = XFS_ERROR(ENOENT);
 128                 }
 129         }
 130         return error;
 131 }
 132
 133 /*
 134  * Allocates a new inode from disk and return a pointer to the
 135  * incore copy. This routine will internally commit the current
 136  * transaction and allocate a new one if the Space Manager needed
 137  * to do an allocation to replenish the inode free-list.
 138  *
 139  * This routine is designed to be called from xfs_create and
 140  * xfs_create_dir.
 141  *
 142  */
 143 int
 144 xfs_dir_ialloc(
 145         xfs_trans_t     **tpp,          /* input: current transaction;
 146                                            output: may be a new transaction. */
 147         xfs_inode_t     *dp,            /* directory within whose allocate
 148                                            the inode. */
 149         mode_t          mode,
 150         nlink_t         nlink,
 151         xfs_dev_t       rdev,
 152         cred_t          *credp,
 153         prid_t          prid,           /* project id */
 154         int             okalloc,        /* ok to allocate new space */
 155         xfs_inode_t     **ipp,          /* pointer to inode; it will be
 156                                            locked. */
 157         int             *committed)
 158
 159 {
 160         xfs_trans_t     *tp;
 161         xfs_trans_t     *ntp;
 162         xfs_inode_t     *ip;
 163         xfs_buf_t       *ialloc_context = NULL;
 164         boolean_t       call_again = B_FALSE;
 165         int             code;
 166         uint            log_res;
 167         uint            log_count;
 168         void            *dqinfo;
 169         uint            tflags;
 170
 171         tp = *tpp;
 172         ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 173
 174         /*
 175          * xfs_ialloc will return a pointer to an incore inode if
 176          * the Space Manager has an available inode on the free
 177          * list. Otherwise, it will do an allocation and replenish
 178          * the freelist.  Since we can only do one allocation per
 179          * transaction without deadlocks, we will need to commit the
 180          * current transaction and start a new one.  We will then
 181          * need to call xfs_ialloc again to get the inode.
 182          *
 183          * If xfs_ialloc did an allocation to replenish the freelist,
 184          * it returns the bp containing the head of the freelist as
 185          * ialloc_context. We will hold a lock on it across the
 186          * transaction commit so that no other process can steal
 187          * the inode(s) that we've just allocated.
 188          */
 189         code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid, okalloc,
 190                           &ialloc_context, &call_again, &ip);
 191
 192         /*
 193          * Return an error if we were unable to allocate a new inode.
 194          * This should only happen if we run out of space on disk or
 195          * encounter a disk error.
 196          */
 197         if (code) {
 198                 *ipp = NULL;
 199                 return code;
 200         }
 201         if (!call_again && (ip == NULL)) {
 202                 *ipp = NULL;
 203                 return XFS_ERROR(ENOSPC);
 204         }
 205
 206         /*
 207          * If call_again is set, then we were unable to get an
 208          * inode in one operation.  We need to commit the current
 209          * transaction and call xfs_ialloc() again.  It is guaranteed
 210          * to succeed the second time.
 211          */
 212         if (call_again) {
 213
 214                 /*
 215                  * Normally, xfs_trans_commit releases all the locks.
 216                  * We call bhold to hang on to the ialloc_context across
 217                  * the commit.  Holding this buffer prevents any other
 218                  * processes from doing any allocations in this
 219                  * allocation group.
 220                  */
 221                 xfs_trans_bhold(tp, ialloc_context);
 222                 /*
 223                  * Save the log reservation so we can use
 224                  * them in the next transaction.
 225                  */
 226                 log_res = xfs_trans_get_log_res(tp);
 227                 log_count = xfs_trans_get_log_count(tp);
 228
 229                 /*
 230                  * We want the quota changes to be associated with the next
 231                  * transaction, NOT this one. So, detach the dqinfo from this
 232                  * and attach it to the next transaction.
 233                  */
 234                 dqinfo = NULL;
 235                 tflags = 0;
 236                 if (tp->t_dqinfo) {
 237                         dqinfo = (void *)tp->t_dqinfo;
 238                         tp->t_dqinfo = NULL;
 239                         tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
 240                         tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
 241                 }
 242
 243                 ntp = xfs_trans_dup(tp);
 244                 code = xfs_trans_commit(tp, 0, NULL);
 245                 tp = ntp;
 246                 if (committed != NULL) {
 247                         *committed = 1;
 248                 }
 249                 /*
 250                  * If we get an error during the commit processing,
 251                  * release the buffer that is still held and return
 252                  * to the caller.
 253                  */
 254                 if (code) {
 255                         xfs_buf_relse(ialloc_context);
 256                         if (dqinfo) {
 257                                 tp->t_dqinfo = dqinfo;
 258                                 XFS_TRANS_FREE_DQINFO(tp->t_mountp, tp);
 259                         }
 260                         *tpp = ntp;
 261                         *ipp = NULL;
 262                         return code;
 263                 }
 264                 code = xfs_trans_reserve(tp, 0, log_res, 0,
 265                                          XFS_TRANS_PERM_LOG_RES, log_count);
 266                 /*
 267                  * Re-attach the quota info that we detached from prev trx.
 268                  */
 269                 if (dqinfo) {
 270                         tp->t_dqinfo = dqinfo;
 271                         tp->t_flags |= tflags;
 272                 }
 273
 274                 if (code) {
 275                         xfs_buf_relse(ialloc_context);
 276                         *tpp = ntp;
 277                         *ipp = NULL;
 278                         return code;
 279                 }
 280                 xfs_trans_bjoin(tp, ialloc_context);
 281
 282                 /*
 283                  * Call ialloc again. Since we've locked out all
 284                  * other allocations in this allocation group,
 285                  * this call should always succeed.
 286                  */
 287                 code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid,
 288                                   okalloc, &ialloc_context, &call_again, &ip);
 289
 290                 /*
 291                  * If we get an error at this point, return to the caller
 292                  * so that the current transaction can be aborted.
 293                  */
 294                 if (code) {
 295                         *tpp = tp;
 296                         *ipp = NULL;
 297                         return code;
 298                 }
 299                 ASSERT ((!call_again) && (ip != NULL));
 300
 301         } else {
 302                 if (committed != NULL) {
 303                         *committed = 0;
 304                 }
 305         }
 306
 307         *ipp = ip;
 308         *tpp = tp;
 309
 310         return 0;
 311 }
 312
 313 /*
 314  * Decrement the link count on an inode & log the change.
 315  * If this causes the link count to go to zero, initiate the
 316  * logging activity required to truncate a file.
 317  */
 318 int                             /* error */
 319 xfs_droplink(
 320         xfs_trans_t *tp,
 321         xfs_inode_t *ip)
 322 {
 323         int     error;
 324
 325         xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
 326
 327         ASSERT (ip->i_d.di_nlink > 0);
 328         ip->i_d.di_nlink--;
 329         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 330
 331         error = 0;
 332         if (ip->i_d.di_nlink == 0) {
 333                 /*
 334                  * We're dropping the last link to this file.
 335                  * Move the on-disk inode to the AGI unlinked list.
 336                  * From xfs_inactive() we will pull the inode from
 337                  * the list and free it.
 338                  */
 339                 error = xfs_iunlink(tp, ip);
 340         }
 341         return error;
 342 }
 343
 344 /*
 345  * This gets called when the inode's version needs to be changed from 1 to 2.
 346  * Currently this happens when the nlink field overflows the old 16-bit value
 347  * or when chproj is called to change the project for the first time.
 348  * As a side effect the superblock version will also get rev'd
 349  * to contain the NLINK bit.
 350  */
 351 void
 352 xfs_bump_ino_vers2(
 353         xfs_trans_t     *tp,
 354         xfs_inode_t     *ip)
 355 {
 356         xfs_mount_t     *mp;
 357         unsigned long           s;
 358
 359         ASSERT(ismrlocked (&ip->i_lock, MR_UPDATE));
 360         ASSERT(ip->i_d.di_version == XFS_DINODE_VERSION_1);
 361
 362         ip->i_d.di_version = XFS_DINODE_VERSION_2;
 363         ip->i_d.di_onlink = 0;
 364         memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
 365         mp = tp->t_mountp;
 366         if (!XFS_SB_VERSION_HASNLINK(&mp->m_sb)) {
 367                 s = XFS_SB_LOCK(mp);
 368                 if (!XFS_SB_VERSION_HASNLINK(&mp->m_sb)) {
 369                         XFS_SB_VERSION_ADDNLINK(&mp->m_sb);
 370                         XFS_SB_UNLOCK(mp, s);
 371                         xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
 372                 } else {
 373                         XFS_SB_UNLOCK(mp, s);
 374                 }
 375         }
 376         /* Caller must log the inode */
 377 }
 378
 379 /*
 380  * Increment the link count on an inode & log the change.
 381  */
 382 int
 383 xfs_bumplink(
 384         xfs_trans_t *tp,
 385         xfs_inode_t *ip)
 386 {
 387         if (ip->i_d.di_nlink >= XFS_MAXLINK)
 388                 return XFS_ERROR(EMLINK);
 389         xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
 390
 391         ASSERT(ip->i_d.di_nlink > 0);
 392         ip->i_d.di_nlink++;
 393         if ((ip->i_d.di_version == XFS_DINODE_VERSION_1) &&
 394             (ip->i_d.di_nlink > XFS_MAXLINK_1)) {
 395                 /*
 396                  * The inode has increased its number of links beyond
 397                  * what can fit in an old format inode.  It now needs
 398                  * to be converted to a version 2 inode with a 32 bit
 399                  * link count.  If this is the first inode in the file
 400                  * system to do this, then we need to bump the superblock
 401                  * version number as well.
 402                  */
 403                 xfs_bump_ino_vers2(tp, ip);
 404         }
 405
 406         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 407         return 0;
 408 }
 409
 410 /*
 411  * Try to truncate the given file to 0 length.  Currently called
 412  * only out of xfs_remove when it has to truncate a file to free
 413  * up space for the remove to proceed.
 414  */
 415 int
 416 xfs_truncate_file(
 417         xfs_mount_t     *mp,
 418         xfs_inode_t     *ip)
 419 {
 420         xfs_trans_t     *tp;
 421         int             error;
 422
 423 #ifdef QUOTADEBUG
 424         /*
 425          * This is called to truncate the quotainodes too.
 426          */
 427         if (XFS_IS_UQUOTA_ON(mp)) {
 428                 if (ip->i_ino != mp->m_sb.sb_uquotino)
 429                         ASSERT(ip->i_udquot);
 430         }
 431         if (XFS_IS_GQUOTA_ON(mp)) {
 432                 if (ip->i_ino != mp->m_sb.sb_gquotino)
 433                         ASSERT(ip->i_gdquot);
 434         }
 435 #endif
 436         /*
 437          * Make the call to xfs_itruncate_start before starting the
 438          * transaction, because we cannot make the call while we're
 439          * in a transaction.
 440          */
 441         xfs_ilock(ip, XFS_IOLOCK_EXCL);
 442         xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, (xfs_fsize_t)0);
 443
 444         tp = xfs_trans_alloc(mp, XFS_TRANS_TRUNCATE_FILE);
 445         if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
 446                                       XFS_TRANS_PERM_LOG_RES,
 447                                       XFS_ITRUNCATE_LOG_COUNT))) {
 448                 xfs_trans_cancel(tp, 0);
 449                 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 450                 return error;
 451         }
 452
 453         /*
 454          * Follow the normal truncate locking protocol.  Since we
 455          * hold the inode in the transaction, we know that it's number
 456          * of references will stay constant.
 457          */
 458         xfs_ilock(ip, XFS_ILOCK_EXCL);
 459         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 460         xfs_trans_ihold(tp, ip);
 461         /*
 462          * Signal a sync xaction.  The only case where that isn't
 463          * the case is if we're truncating an already unlinked file
 464          * on a wsync fs.  In that case, we know the blocks can't
 465          * reappear in the file because the links to file are
 466          * permanently toast.  Currently, we're always going to
 467          * want a sync transaction because this code is being
 468          * called from places where nlink is guaranteed to be 1
 469          * but I'm leaving the tests in to protect against future
 470          * changes -- rcc.
 471          */
 472         error = xfs_itruncate_finish(&tp, ip, (xfs_fsize_t)0,
 473                                      XFS_DATA_FORK,
 474                                      ((ip->i_d.di_nlink != 0 ||
 475                                        !(mp->m_flags & XFS_MOUNT_WSYNC))
 476                                       ? 1 : 0));
 477         if (error) {
 478                 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
 479                                  XFS_TRANS_ABORT);
 480         } else {
 481                 xfs_ichgtime(ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 482                 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES,
 483                                          NULL);
 484         }
 485         xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 486
 487         return error;
 488 }