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_mount.h"
  29 #include "xfs_bmap_btree.h"
  30 #include "xfs_dinode.h"
  31 #include "xfs_inode.h"
  32 #include "xfs_inode_item.h"
  33 #include "xfs_bmap.h"
  34 #include "xfs_error.h"
  35 #include "xfs_quota.h"
  36 #include "xfs_itable.h"
  37 #include "xfs_utils.h"
  38
  39
  40 /*
  41  * Allocates a new inode from disk and return a pointer to the
  42  * incore copy. This routine will internally commit the current
  43  * transaction and allocate a new one if the Space Manager needed
  44  * to do an allocation to replenish the inode free-list.
  45  *
  46  * This routine is designed to be called from xfs_create and
  47  * xfs_create_dir.
  48  *
  49  */
  50 int
  51 xfs_dir_ialloc(
  52         xfs_trans_t     **tpp,          /* input: current transaction;
  53                                            output: may be a new transaction. */
  54         xfs_inode_t     *dp,            /* directory within whose allocate
  55                                            the inode. */
  56         mode_t          mode,
  57         xfs_nlink_t     nlink,
  58         xfs_dev_t       rdev,
  59         cred_t          *credp,
  60         prid_t          prid,           /* project id */
  61         int             okalloc,        /* ok to allocate new space */
  62         xfs_inode_t     **ipp,          /* pointer to inode; it will be
  63                                            locked. */
  64         int             *committed)
  65
  66 {
  67         xfs_trans_t     *tp;
  68         xfs_trans_t     *ntp;
  69         xfs_inode_t     *ip;
  70         xfs_buf_t       *ialloc_context = NULL;
  71         boolean_t       call_again = B_FALSE;
  72         int             code;
  73         uint            log_res;
  74         uint            log_count;
  75         void            *dqinfo;
  76         uint            tflags;
  77
  78         tp = *tpp;
  79         ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
  80
  81         /*
  82          * xfs_ialloc will return a pointer to an incore inode if
  83          * the Space Manager has an available inode on the free
  84          * list. Otherwise, it will do an allocation and replenish
  85          * the freelist.  Since we can only do one allocation per
  86          * transaction without deadlocks, we will need to commit the
  87          * current transaction and start a new one.  We will then
  88          * need to call xfs_ialloc again to get the inode.
  89          *
  90          * If xfs_ialloc did an allocation to replenish the freelist,
  91          * it returns the bp containing the head of the freelist as
  92          * ialloc_context. We will hold a lock on it across the
  93          * transaction commit so that no other process can steal
  94          * the inode(s) that we've just allocated.
  95          */
  96         code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid, okalloc,
  97                           &ialloc_context, &call_again, &ip);
  98
  99         /*
 100          * Return an error if we were unable to allocate a new inode.
 101          * This should only happen if we run out of space on disk or
 102          * encounter a disk error.
 103          */
 104         if (code) {
 105                 *ipp = NULL;
 106                 return code;
 107         }
 108         if (!call_again && (ip == NULL)) {
 109                 *ipp = NULL;
 110                 return XFS_ERROR(ENOSPC);
 111         }
 112
 113         /*
 114          * If call_again is set, then we were unable to get an
 115          * inode in one operation.  We need to commit the current
 116          * transaction and call xfs_ialloc() again.  It is guaranteed
 117          * to succeed the second time.
 118          */
 119         if (call_again) {
 120
 121                 /*
 122                  * Normally, xfs_trans_commit releases all the locks.
 123                  * We call bhold to hang on to the ialloc_context across
 124                  * the commit.  Holding this buffer prevents any other
 125                  * processes from doing any allocations in this
 126                  * allocation group.
 127                  */
 128                 xfs_trans_bhold(tp, ialloc_context);
 129                 /*
 130                  * Save the log reservation so we can use
 131                  * them in the next transaction.
 132                  */
 133                 log_res = xfs_trans_get_log_res(tp);
 134                 log_count = xfs_trans_get_log_count(tp);
 135
 136                 /*
 137                  * We want the quota changes to be associated with the next
 138                  * transaction, NOT this one. So, detach the dqinfo from this
 139                  * and attach it to the next transaction.
 140                  */
 141                 dqinfo = NULL;
 142                 tflags = 0;
 143                 if (tp->t_dqinfo) {
 144                         dqinfo = (void *)tp->t_dqinfo;
 145                         tp->t_dqinfo = NULL;
 146                         tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
 147                         tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
 148                 }
 149
 150                 ntp = xfs_trans_dup(tp);
 151                 code = xfs_trans_commit(tp, 0);
 152                 tp = ntp;
 153                 if (committed != NULL) {
 154                         *committed = 1;
 155                 }
 156                 /*
 157                  * If we get an error during the commit processing,
 158                  * release the buffer that is still held and return
 159                  * to the caller.
 160                  */
 161                 if (code) {
 162                         xfs_buf_relse(ialloc_context);
 163                         if (dqinfo) {
 164                                 tp->t_dqinfo = dqinfo;
 165                                 xfs_trans_free_dqinfo(tp);
 166                         }
 167                         *tpp = ntp;
 168                         *ipp = NULL;
 169                         return code;
 170                 }
 171
 172                 /*
 173                  * transaction commit worked ok so we can drop the extra ticket
 174                  * reference that we gained in xfs_trans_dup()
 175                  */
 176                 xfs_log_ticket_put(tp->t_ticket);
 177                 code = xfs_trans_reserve(tp, 0, log_res, 0,
 178                                          XFS_TRANS_PERM_LOG_RES, log_count);
 179                 /*
 180                  * Re-attach the quota info that we detached from prev trx.
 181                  */
 182                 if (dqinfo) {
 183                         tp->t_dqinfo = dqinfo;
 184                         tp->t_flags |= tflags;
 185                 }
 186
 187                 if (code) {
 188                         xfs_buf_relse(ialloc_context);
 189                         *tpp = ntp;
 190                         *ipp = NULL;
 191                         return code;
 192                 }
 193                 xfs_trans_bjoin(tp, ialloc_context);
 194
 195                 /*
 196                  * Call ialloc again. Since we've locked out all
 197                  * other allocations in this allocation group,
 198                  * this call should always succeed.
 199                  */
 200                 code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid,
 201                                   okalloc, &ialloc_context, &call_again, &ip);
 202
 203                 /*
 204                  * If we get an error at this point, return to the caller
 205                  * so that the current transaction can be aborted.
 206                  */
 207                 if (code) {
 208                         *tpp = tp;
 209                         *ipp = NULL;
 210                         return code;
 211                 }
 212                 ASSERT ((!call_again) && (ip != NULL));
 213
 214         } else {
 215                 if (committed != NULL) {
 216                         *committed = 0;
 217                 }
 218         }
 219
 220         *ipp = ip;
 221         *tpp = tp;
 222
 223         return 0;
 224 }
 225
 226 /*
 227  * Decrement the link count on an inode & log the change.
 228  * If this causes the link count to go to zero, initiate the
 229  * logging activity required to truncate a file.
 230  */
 231 int                             /* error */
 232 xfs_droplink(
 233         xfs_trans_t *tp,
 234         xfs_inode_t *ip)
 235 {
 236         int     error;
 237
 238         xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
 239
 240         ASSERT (ip->i_d.di_nlink > 0);
 241         ip->i_d.di_nlink--;
 242         drop_nlink(VFS_I(ip));
 243         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 244
 245         error = 0;
 246         if (ip->i_d.di_nlink == 0) {
 247                 /*
 248                  * We're dropping the last link to this file.
 249                  * Move the on-disk inode to the AGI unlinked list.
 250                  * From xfs_inactive() we will pull the inode from
 251                  * the list and free it.
 252                  */
 253                 error = xfs_iunlink(tp, ip);
 254         }
 255         return error;
 256 }
 257
 258 /*
 259  * This gets called when the inode's version needs to be changed from 1 to 2.
 260  * Currently this happens when the nlink field overflows the old 16-bit value
 261  * or when chproj is called to change the project for the first time.
 262  * As a side effect the superblock version will also get rev'd
 263  * to contain the NLINK bit.
 264  */
 265 void
 266 xfs_bump_ino_vers2(
 267         xfs_trans_t     *tp,
 268         xfs_inode_t     *ip)
 269 {
 270         xfs_mount_t     *mp;
 271
 272         ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 273         ASSERT(ip->i_d.di_version == 1);
 274
 275         ip->i_d.di_version = 2;
 276         ip->i_d.di_onlink = 0;
 277         memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
 278         mp = tp->t_mountp;
 279         if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
 280                 spin_lock(&mp->m_sb_lock);
 281                 if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
 282                         xfs_sb_version_addnlink(&mp->m_sb);
 283                         spin_unlock(&mp->m_sb_lock);
 284                         xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
 285                 } else {
 286                         spin_unlock(&mp->m_sb_lock);
 287                 }
 288         }
 289         /* Caller must log the inode */
 290 }
 291
 292 /*
 293  * Increment the link count on an inode & log the change.
 294  */
 295 int
 296 xfs_bumplink(
 297         xfs_trans_t *tp,
 298         xfs_inode_t *ip)
 299 {
 300         if (ip->i_d.di_nlink >= XFS_MAXLINK)
 301                 return XFS_ERROR(EMLINK);
 302         xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
 303
 304         ASSERT(ip->i_d.di_nlink > 0);
 305         ip->i_d.di_nlink++;
 306         inc_nlink(VFS_I(ip));
 307         if ((ip->i_d.di_version == 1) &&
 308             (ip->i_d.di_nlink > XFS_MAXLINK_1)) {
 309                 /*
 310                  * The inode has increased its number of links beyond
 311                  * what can fit in an old format inode.  It now needs
 312                  * to be converted to a version 2 inode with a 32 bit
 313                  * link count.  If this is the first inode in the file
 314                  * system to do this, then we need to bump the superblock
 315                  * version number as well.
 316                  */
 317                 xfs_bump_ino_vers2(tp, ip);
 318         }
 319
 320         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 321         return 0;
 322 }