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