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_log.h"
  22 #include "xfs_trans.h"
  23 #include "xfs_sb.h"
  24 #include "xfs_ag.h"
  25 #include "xfs_dir2.h"
  26 #include "xfs_mount.h"
  27 #include "xfs_bmap_btree.h"
  28 #include "xfs_dinode.h"
  29 #include "xfs_inode.h"
  30 #include "xfs_inode_item.h"
  31 #include "xfs_bmap.h"
  32 #include "xfs_error.h"
  33 #include "xfs_quota.h"
  34 #include "xfs_itable.h"
  35 #include "xfs_utils.h"
  36
  37
  38 /*
  39  * Allocates a new inode from disk and return a pointer to the
  40  * incore copy. This routine will internally commit the current
  41  * transaction and allocate a new one if the Space Manager needed
  42  * to do an allocation to replenish the inode free-list.
  43  *
  44  * This routine is designed to be called from xfs_create and
  45  * xfs_create_dir.
  46  *
  47  */
  48 int
  49 xfs_dir_ialloc(
  50         xfs_trans_t     **tpp,          /* input: current transaction;
  51                                            output: may be a new transaction. */
  52         xfs_inode_t     *dp,            /* directory within whose allocate
  53                                            the inode. */
  54         umode_t         mode,
  55         xfs_nlink_t     nlink,
  56         xfs_dev_t       rdev,
  57         prid_t          prid,           /* project id */
  58         int             okalloc,        /* ok to allocate new space */
  59         xfs_inode_t     **ipp,          /* pointer to inode; it will be
  60                                            locked. */
  61         int             *committed)
  62
  63 {
  64         xfs_trans_t     *tp;
  65         xfs_trans_t     *ntp;
  66         xfs_inode_t     *ip;
  67         xfs_buf_t       *ialloc_context = NULL;
  68         int             code;
  69         uint            log_res;
  70         uint            log_count;
  71         void            *dqinfo;
  72         uint            tflags;
  73
  74         tp = *tpp;
  75         ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
  76
  77         /*
  78          * xfs_ialloc will return a pointer to an incore inode if
  79          * the Space Manager has an available inode on the free
  80          * list. Otherwise, it will do an allocation and replenish
  81          * the freelist.  Since we can only do one allocation per
  82          * transaction without deadlocks, we will need to commit the
  83          * current transaction and start a new one.  We will then
  84          * need to call xfs_ialloc again to get the inode.
  85          *
  86          * If xfs_ialloc did an allocation to replenish the freelist,
  87          * it returns the bp containing the head of the freelist as
  88          * ialloc_context. We will hold a lock on it across the
  89          * transaction commit so that no other process can steal
  90          * the inode(s) that we've just allocated.
  91          */
  92         code = xfs_ialloc(tp, dp, mode, nlink, rdev, prid, okalloc,
  93                           &ialloc_context, &ip);
  94
  95         /*
  96          * Return an error if we were unable to allocate a new inode.
  97          * This should only happen if we run out of space on disk or
  98          * encounter a disk error.
  99          */
 100         if (code) {
 101                 *ipp = NULL;
 102                 return code;
 103         }
 104         if (!ialloc_context && !ip) {
 105                 *ipp = NULL;
 106                 return XFS_ERROR(ENOSPC);
 107         }
 108
 109         /*
 110          * If the AGI buffer is non-NULL, then we were unable to get an
 111          * inode in one operation.  We need to commit the current
 112          * transaction and call xfs_ialloc() again.  It is guaranteed
 113          * to succeed the second time.
 114          */
 115         if (ialloc_context) {
 116                 /*
 117                  * Normally, xfs_trans_commit releases all the locks.
 118                  * We call bhold to hang on to the ialloc_context across
 119                  * the commit.  Holding this buffer prevents any other
 120                  * processes from doing any allocations in this
 121                  * allocation group.
 122                  */
 123                 xfs_trans_bhold(tp, ialloc_context);
 124                 /*
 125                  * Save the log reservation so we can use
 126                  * them in the next transaction.
 127                  */
 128                 log_res = xfs_trans_get_log_res(tp);
 129                 log_count = xfs_trans_get_log_count(tp);
 130
 131                 /*
 132                  * We want the quota changes to be associated with the next
 133                  * transaction, NOT this one. So, detach the dqinfo from this
 134                  * and attach it to the next transaction.
 135                  */
 136                 dqinfo = NULL;
 137                 tflags = 0;
 138                 if (tp->t_dqinfo) {
 139                         dqinfo = (void *)tp->t_dqinfo;
 140                         tp->t_dqinfo = NULL;
 141                         tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
 142                         tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
 143                 }
 144
 145                 ntp = xfs_trans_dup(tp);
 146                 code = xfs_trans_commit(tp, 0);
 147                 tp = ntp;
 148                 if (committed != NULL) {
 149                         *committed = 1;
 150                 }
 151                 /*
 152                  * If we get an error during the commit processing,
 153                  * release the buffer that is still held and return
 154                  * to the caller.
 155                  */
 156                 if (code) {
 157                         xfs_buf_relse(ialloc_context);
 158                         if (dqinfo) {
 159                                 tp->t_dqinfo = dqinfo;
 160                                 xfs_trans_free_dqinfo(tp);
 161                         }
 162                         *tpp = ntp;
 163                         *ipp = NULL;
 164                         return code;
 165                 }
 166
 167                 /*
 168                  * transaction commit worked ok so we can drop the extra ticket
 169                  * reference that we gained in xfs_trans_dup()
 170                  */
 171                 xfs_log_ticket_put(tp->t_ticket);
 172                 code = xfs_trans_reserve(tp, 0, log_res, 0,
 173                                          XFS_TRANS_PERM_LOG_RES, log_count);
 174                 /*
 175                  * Re-attach the quota info that we detached from prev trx.
 176                  */
 177                 if (dqinfo) {
 178                         tp->t_dqinfo = dqinfo;
 179                         tp->t_flags |= tflags;
 180                 }
 181
 182                 if (code) {
 183                         xfs_buf_relse(ialloc_context);
 184                         *tpp = ntp;
 185                         *ipp = NULL;
 186                         return code;
 187                 }
 188                 xfs_trans_bjoin(tp, ialloc_context);
 189
 190                 /*
 191                  * Call ialloc again. Since we've locked out all
 192                  * other allocations in this allocation group,
 193                  * this call should always succeed.
 194                  */
 195                 code = xfs_ialloc(tp, dp, mode, nlink, rdev, prid,
 196                                   okalloc, &ialloc_context, &ip);
 197
 198                 /*
 199                  * If we get an error at this point, return to the caller
 200                  * so that the current transaction can be aborted.
 201                  */
 202                 if (code) {
 203                         *tpp = tp;
 204                         *ipp = NULL;
 205                         return code;
 206                 }
 207                 ASSERT(!ialloc_context && ip);
 208
 209         } else {
 210                 if (committed != NULL)
 211                         *committed = 0;
 212         }
 213
 214         *ipp = ip;
 215         *tpp = tp;
 216
 217         return 0;
 218 }
 219
 220 /*
 221  * Decrement the link count on an inode & log the change.
 222  * If this causes the link count to go to zero, initiate the
 223  * logging activity required to truncate a file.
 224  */
 225 int                             /* error */
 226 xfs_droplink(
 227         xfs_trans_t *tp,
 228         xfs_inode_t *ip)
 229 {
 230         int     error;
 231
 232         xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
 233
 234         ASSERT (ip->i_d.di_nlink > 0);
 235         ip->i_d.di_nlink--;
 236         drop_nlink(VFS_I(ip));
 237         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 238
 239         error = 0;
 240         if (ip->i_d.di_nlink == 0) {
 241                 /*
 242                  * We're dropping the last link to this file.
 243                  * Move the on-disk inode to the AGI unlinked list.
 244                  * From xfs_inactive() we will pull the inode from
 245                  * the list and free it.
 246                  */
 247                 error = xfs_iunlink(tp, ip);
 248         }
 249         return error;
 250 }
 251
 252 /*
 253  * This gets called when the inode's version needs to be changed from 1 to 2.
 254  * Currently this happens when the nlink field overflows the old 16-bit value
 255  * or when chproj is called to change the project for the first time.
 256  * As a side effect the superblock version will also get rev'd
 257  * to contain the NLINK bit.
 258  */
 259 void
 260 xfs_bump_ino_vers2(
 261         xfs_trans_t     *tp,
 262         xfs_inode_t     *ip)
 263 {
 264         xfs_mount_t     *mp;
 265
 266         ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 267         ASSERT(ip->i_d.di_version == 1);
 268
 269         ip->i_d.di_version = 2;
 270         ip->i_d.di_onlink = 0;
 271         memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
 272         mp = tp->t_mountp;
 273         if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
 274                 spin_lock(&mp->m_sb_lock);
 275                 if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
 276                         xfs_sb_version_addnlink(&mp->m_sb);
 277                         spin_unlock(&mp->m_sb_lock);
 278                         xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
 279                 } else {
 280                         spin_unlock(&mp->m_sb_lock);
 281                 }
 282         }
 283         /* Caller must log the inode */
 284 }
 285
 286 /*
 287  * Increment the link count on an inode & log the change.
 288  */
 289 int
 290 xfs_bumplink(
 291         xfs_trans_t *tp,
 292         xfs_inode_t *ip)
 293 {
 294         xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
 295
 296         ASSERT(ip->i_d.di_nlink > 0);
 297         ip->i_d.di_nlink++;
 298         inc_nlink(VFS_I(ip));
 299         if ((ip->i_d.di_version == 1) &&
 300             (ip->i_d.di_nlink > XFS_MAXLINK_1)) {
 301                 /*
 302                  * The inode has increased its number of links beyond
 303                  * what can fit in an old format inode.  It now needs
 304                  * to be converted to a version 2 inode with a 32 bit
 305                  * link count.  If this is the first inode in the file
 306                  * system to do this, then we need to bump the superblock
 307                  * version number as well.
 308                  */
 309                 xfs_bump_ino_vers2(tp, ip);
 310         }
 311
 312         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 313         return 0;
 314 }