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xfs_vnodeops.c

/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_itable.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_rw.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_utils.h"
#include "xfs_rtalloc.h"
#include "xfs_trans_space.h"
#include "xfs_log_priv.h"
#include "xfs_filestream.h"
#include "xfs_vnodeops.h"

int
xfs_setattr(
      struct xfs_inode  *ip,
      struct iattr            *iattr,
      int               flags)
{
      xfs_mount_t       *mp = ip->i_mount;
      struct inode            *inode = VFS_I(ip);
      int               mask = iattr->ia_valid;
      xfs_trans_t       *tp;
      int               code;
      uint              lock_flags;
      uint              commit_flags=0;
      uid_t             uid=0, iuid=0;
      gid_t             gid=0, igid=0;
      int               timeflags = 0;
      struct xfs_dquot  *udqp, *gdqp, *olddquot1, *olddquot2;
      int               need_iolock = 1;

      xfs_itrace_entry(ip);

      if (mp->m_flags & XFS_MOUNT_RDONLY)
            return XFS_ERROR(EROFS);

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      code = -inode_change_ok(inode, iattr);
      if (code)
            return code;

      olddquot1 = olddquot2 = NULL;
      udqp = gdqp = NULL;

      /*
       * If disk quotas is on, we make sure that the dquots do exist on disk,
       * before we start any other transactions. Trying to do this later
       * is messy. We don't care to take a readlock to look at the ids
       * in inode here, because we can't hold it across the trans_reserve.
       * If the IDs do change before we take the ilock, we're covered
       * because the i_*dquot fields will get updated anyway.
       */
      if (XFS_IS_QUOTA_ON(mp) && (mask & (ATTR_UID|ATTR_GID))) {
            uint  qflags = 0;

            if ((mask & ATTR_UID) && XFS_IS_UQUOTA_ON(mp)) {
                  uid = iattr->ia_uid;
                  qflags |= XFS_QMOPT_UQUOTA;
            } else {
                  uid = ip->i_d.di_uid;
            }
            if ((mask & ATTR_GID) && XFS_IS_GQUOTA_ON(mp)) {
                  gid = iattr->ia_gid;
                  qflags |= XFS_QMOPT_GQUOTA;
            }  else {
                  gid = ip->i_d.di_gid;
            }

            /*
             * We take a reference when we initialize udqp and gdqp,
             * so it is important that we never blindly double trip on
             * the same variable. See xfs_create() for an example.
             */
            ASSERT(udqp == NULL);
            ASSERT(gdqp == NULL);
            code = xfs_qm_vop_dqalloc(ip, uid, gid, ip->i_d.di_projid,
                               qflags, &udqp, &gdqp);
            if (code)
                  return code;
      }

      /*
       * For the other attributes, we acquire the inode lock and
       * first do an error checking pass.
       */
      tp = NULL;
      lock_flags = XFS_ILOCK_EXCL;
      if (flags & XFS_ATTR_NOLOCK)
            need_iolock = 0;
      if (!(mask & ATTR_SIZE)) {
            if ((mask != (ATTR_CTIME|ATTR_ATIME|ATTR_MTIME)) ||
                (mp->m_flags & XFS_MOUNT_WSYNC)) {
                  tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
                  commit_flags = 0;
                  if ((code = xfs_trans_reserve(tp, 0,
                                         XFS_ICHANGE_LOG_RES(mp), 0,
                                         0, 0))) {
                        lock_flags = 0;
                        goto error_return;
                  }
            }
      } else {
            if (DM_EVENT_ENABLED(ip, DM_EVENT_TRUNCATE) &&
                !(flags & XFS_ATTR_DMI)) {
                  int dmflags = AT_DELAY_FLAG(flags) | DM_SEM_FLAG_WR;
                  code = XFS_SEND_DATA(mp, DM_EVENT_TRUNCATE, ip,
                        iattr->ia_size, 0, dmflags, NULL);
                  if (code) {
                        lock_flags = 0;
                        goto error_return;
                  }
            }
            if (need_iolock)
                  lock_flags |= XFS_IOLOCK_EXCL;
      }

      xfs_ilock(ip, lock_flags);

      /*
       * Change file ownership.  Must be the owner or privileged.
       */
      if (mask & (ATTR_UID|ATTR_GID)) {
            /*
             * These IDs could have changed since we last looked at them.
             * But, we're assured that if the ownership did change
             * while we didn't have the inode locked, inode's dquot(s)
             * would have changed also.
             */
            iuid = ip->i_d.di_uid;
            igid = ip->i_d.di_gid;
            gid = (mask & ATTR_GID) ? iattr->ia_gid : igid;
            uid = (mask & ATTR_UID) ? iattr->ia_uid : iuid;

            /*
             * Do a quota reservation only if uid/gid is actually
             * going to change.
             */
            if (XFS_IS_QUOTA_RUNNING(mp) &&
                ((XFS_IS_UQUOTA_ON(mp) && iuid != uid) ||
                 (XFS_IS_GQUOTA_ON(mp) && igid != gid))) {
                  ASSERT(tp);
                  code = xfs_qm_vop_chown_reserve(tp, ip, udqp, gdqp,
                                    capable(CAP_FOWNER) ?
                                    XFS_QMOPT_FORCE_RES : 0);
                  if (code)   /* out of quota */
                        goto error_return;
            }
      }

      /*
       * Truncate file.  Must have write permission and not be a directory.
       */
      if (mask & ATTR_SIZE) {
            /* Short circuit the truncate case for zero length files */
            if (iattr->ia_size == 0 &&
                ip->i_size == 0 && ip->i_d.di_nextents == 0) {
                  xfs_iunlock(ip, XFS_ILOCK_EXCL);
                  lock_flags &= ~XFS_ILOCK_EXCL;
                  if (mask & ATTR_CTIME)
                        xfs_ichgtime(ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
                  code = 0;
                  goto error_return;
            }

            if (S_ISDIR(ip->i_d.di_mode)) {
                  code = XFS_ERROR(EISDIR);
                  goto error_return;
            } else if (!S_ISREG(ip->i_d.di_mode)) {
                  code = XFS_ERROR(EINVAL);
                  goto error_return;
            }

            /*
             * Make sure that the dquots are attached to the inode.
             */
            code = xfs_qm_dqattach_locked(ip, 0);
            if (code)
                  goto error_return;

            /*
             * Now we can make the changes.  Before we join the inode
             * to the transaction, if ATTR_SIZE is set then take care of
             * the part of the truncation that must be done without the
             * inode lock.  This needs to be done before joining the inode
             * to the transaction, because the inode cannot be unlocked
             * once it is a part of the transaction.
             */
            if (iattr->ia_size > ip->i_size) {
                  /*
                   * Do the first part of growing a file: zero any data
                   * in the last block that is beyond the old EOF.  We
                   * need to do this before the inode is joined to the
                   * transaction to modify the i_size.
                   */
                  code = xfs_zero_eof(ip, iattr->ia_size, ip->i_size);
            }
            xfs_iunlock(ip, XFS_ILOCK_EXCL);

            /*
             * We are going to log the inode size change in this
             * transaction so any previous writes that are beyond the on
             * disk EOF and the new EOF that have not been written out need
             * to be written here. If we do not write the data out, we
             * expose ourselves to the null files problem.
             *
             * Only flush from the on disk size to the smaller of the in
             * memory file size or the new size as that's the range we
             * really care about here and prevents waiting for other data
             * not within the range we care about here.
             */
            if (!code &&
                ip->i_size != ip->i_d.di_size &&
                iattr->ia_size > ip->i_d.di_size) {
                  code = xfs_flush_pages(ip,
                              ip->i_d.di_size, iattr->ia_size,
                              XFS_B_ASYNC, FI_NONE);
            }

            /* wait for all I/O to complete */
            xfs_ioend_wait(ip);

            if (!code)
                  code = xfs_itruncate_data(ip, iattr->ia_size);
            if (code) {
                  ASSERT(tp == NULL);
                  lock_flags &= ~XFS_ILOCK_EXCL;
                  ASSERT(lock_flags == XFS_IOLOCK_EXCL);
                  goto error_return;
            }
            tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_SIZE);
            if ((code = xfs_trans_reserve(tp, 0,
                                   XFS_ITRUNCATE_LOG_RES(mp), 0,
                                   XFS_TRANS_PERM_LOG_RES,
                                   XFS_ITRUNCATE_LOG_COUNT))) {
                  xfs_trans_cancel(tp, 0);
                  if (need_iolock)
                        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
                  return code;
            }
            commit_flags = XFS_TRANS_RELEASE_LOG_RES;
            xfs_ilock(ip, XFS_ILOCK_EXCL);

            xfs_trans_ijoin(tp, ip, lock_flags);
            xfs_trans_ihold(tp, ip);

            /*
             * Only change the c/mtime if we are changing the size
             * or we are explicitly asked to change it. This handles
             * the semantic difference between truncate() and ftruncate()
             * as implemented in the VFS.
             */
            if (iattr->ia_size != ip->i_size || (mask & ATTR_CTIME))
                  timeflags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;

            if (iattr->ia_size > ip->i_size) {
                  ip->i_d.di_size = iattr->ia_size;
                  ip->i_size = iattr->ia_size;
                  if (!(flags & XFS_ATTR_DMI))
                        xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
                  xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
            } else if (iattr->ia_size <= ip->i_size ||
                     (iattr->ia_size == 0 && ip->i_d.di_nextents)) {
                  /*
                   * signal a sync transaction unless
                   * we're truncating an already unlinked
                   * file on a wsync filesystem
                   */
                  code = xfs_itruncate_finish(&tp, ip, iattr->ia_size,
                                  XFS_DATA_FORK,
                                  ((ip->i_d.di_nlink != 0 ||
                                    !(mp->m_flags & XFS_MOUNT_WSYNC))
                                   ? 1 : 0));
                  if (code)
                        goto abort_return;
                  /*
                   * Truncated "down", so we're removing references
                   * to old data here - if we now delay flushing for
                   * a long time, we expose ourselves unduly to the
                   * notorious NULL files problem.  So, we mark this
                   * vnode and flush it when the file is closed, and
                   * do not wait the usual (long) time for writeout.
                   */
                  xfs_iflags_set(ip, XFS_ITRUNCATED);
            }
      } else if (tp) {
            xfs_trans_ijoin(tp, ip, lock_flags);
            xfs_trans_ihold(tp, ip);
      }

      /*
       * Change file ownership.  Must be the owner or privileged.
       */
      if (mask & (ATTR_UID|ATTR_GID)) {
            /*
             * CAP_FSETID overrides the following restrictions:
             *
             * The set-user-ID and set-group-ID bits of a file will be
             * cleared upon successful return from chown()
             */
            if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) &&
                !capable(CAP_FSETID)) {
                  ip->i_d.di_mode &= ~(S_ISUID|S_ISGID);
            }

            /*
             * Change the ownerships and register quota modifications
             * in the transaction.
             */
            if (iuid != uid) {
                  if (XFS_IS_QUOTA_RUNNING(mp) && XFS_IS_UQUOTA_ON(mp)) {
                        ASSERT(mask & ATTR_UID);
                        ASSERT(udqp);
                        olddquot1 = xfs_qm_vop_chown(tp, ip,
                                          &ip->i_udquot, udqp);
                  }
                  ip->i_d.di_uid = uid;
                  inode->i_uid = uid;
            }
            if (igid != gid) {
                  if (XFS_IS_QUOTA_RUNNING(mp) && XFS_IS_GQUOTA_ON(mp)) {
                        ASSERT(!XFS_IS_PQUOTA_ON(mp));
                        ASSERT(mask & ATTR_GID);
                        ASSERT(gdqp);
                        olddquot2 = xfs_qm_vop_chown(tp, ip,
                                          &ip->i_gdquot, gdqp);
                  }
                  ip->i_d.di_gid = gid;
                  inode->i_gid = gid;
            }

            xfs_trans_log_inode (tp, ip, XFS_ILOG_CORE);
            timeflags |= XFS_ICHGTIME_CHG;
      }

      /*
       * Change file access modes.
       */
      if (mask & ATTR_MODE) {
            umode_t mode = iattr->ia_mode;

            if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
                  mode &= ~S_ISGID;

            ip->i_d.di_mode &= S_IFMT;
            ip->i_d.di_mode |= mode & ~S_IFMT;

            inode->i_mode &= S_IFMT;
            inode->i_mode |= mode & ~S_IFMT;

            xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
            timeflags |= XFS_ICHGTIME_CHG;
      }

      /*
       * Change file access or modified times.
       */
      if (mask & (ATTR_ATIME|ATTR_MTIME)) {
            if (mask & ATTR_ATIME) {
                  inode->i_atime = iattr->ia_atime;
                  ip->i_d.di_atime.t_sec = iattr->ia_atime.tv_sec;
                  ip->i_d.di_atime.t_nsec = iattr->ia_atime.tv_nsec;
                  ip->i_update_core = 1;
            }
            if (mask & ATTR_MTIME) {
                  inode->i_mtime = iattr->ia_mtime;
                  ip->i_d.di_mtime.t_sec = iattr->ia_mtime.tv_sec;
                  ip->i_d.di_mtime.t_nsec = iattr->ia_mtime.tv_nsec;
                  timeflags &= ~XFS_ICHGTIME_MOD;
                  timeflags |= XFS_ICHGTIME_CHG;
            }
            if (tp && (mask & (ATTR_MTIME_SET|ATTR_ATIME_SET)))
                  xfs_trans_log_inode (tp, ip, XFS_ILOG_CORE);
      }

      /*
       * Change file inode change time only if ATTR_CTIME set
       * AND we have been called by a DMI function.
       */

      if ((flags & XFS_ATTR_DMI) && (mask & ATTR_CTIME)) {
            inode->i_ctime = iattr->ia_ctime;
            ip->i_d.di_ctime.t_sec = iattr->ia_ctime.tv_sec;
            ip->i_d.di_ctime.t_nsec = iattr->ia_ctime.tv_nsec;
            ip->i_update_core = 1;
            timeflags &= ~XFS_ICHGTIME_CHG;
      }

      /*
       * Send out timestamp changes that need to be set to the
       * current time.  Not done when called by a DMI function.
       */
      if (timeflags && !(flags & XFS_ATTR_DMI))
            xfs_ichgtime(ip, timeflags);

      XFS_STATS_INC(xs_ig_attrchg);

      /*
       * If this is a synchronous mount, make sure that the
       * transaction goes to disk before returning to the user.
       * This is slightly sub-optimal in that truncates require
       * two sync transactions instead of one for wsync filesystems.
       * One for the truncate and one for the timestamps since we
       * don't want to change the timestamps unless we're sure the
       * truncate worked.  Truncates are less than 1% of the laddis
       * mix so this probably isn't worth the trouble to optimize.
       */
      code = 0;
      if (tp) {
            if (mp->m_flags & XFS_MOUNT_WSYNC)
                  xfs_trans_set_sync(tp);

            code = xfs_trans_commit(tp, commit_flags);
      }

      xfs_iunlock(ip, lock_flags);

      /*
       * Release any dquot(s) the inode had kept before chown.
       */
      xfs_qm_dqrele(olddquot1);
      xfs_qm_dqrele(olddquot2);
      xfs_qm_dqrele(udqp);
      xfs_qm_dqrele(gdqp);

      if (code)
            return code;

      /*
       * XXX(hch): Updating the ACL entries is not atomic vs the i_mode
       *         update.  We could avoid this with linked transactions
       *         and passing down the transaction pointer all the way
       *         to attr_set.  No previous user of the generic
       *         Posix ACL code seems to care about this issue either.
       */
      if ((mask & ATTR_MODE) && !(flags & XFS_ATTR_NOACL)) {
            code = -xfs_acl_chmod(inode);
            if (code)
                  return XFS_ERROR(code);
      }

      if (DM_EVENT_ENABLED(ip, DM_EVENT_ATTRIBUTE) &&
          !(flags & XFS_ATTR_DMI)) {
            (void) XFS_SEND_NAMESP(mp, DM_EVENT_ATTRIBUTE, ip, DM_RIGHT_NULL,
                              NULL, DM_RIGHT_NULL, NULL, NULL,
                              0, 0, AT_DELAY_FLAG(flags));
      }
      return 0;

 abort_return:
      commit_flags |= XFS_TRANS_ABORT;
      /* FALLTHROUGH */
 error_return:
      xfs_qm_dqrele(udqp);
      xfs_qm_dqrele(gdqp);
      if (tp) {
            xfs_trans_cancel(tp, commit_flags);
      }
      if (lock_flags != 0) {
            xfs_iunlock(ip, lock_flags);
      }
      return code;
}

/*
 * The maximum pathlen is 1024 bytes. Since the minimum file system
 * blocksize is 512 bytes, we can get a max of 2 extents back from
 * bmapi.
 */
#define SYMLINK_MAPS 2

STATIC int
xfs_readlink_bmap(
      xfs_inode_t *ip,
      char        *link)
{
      xfs_mount_t *mp = ip->i_mount;
      int         pathlen = ip->i_d.di_size;
      int             nmaps = SYMLINK_MAPS;
      xfs_bmbt_irec_t mval[SYMLINK_MAPS];
      xfs_daddr_t d;
      int         byte_cnt;
      int         n;
      xfs_buf_t   *bp;
      int         error = 0;

      error = xfs_bmapi(NULL, ip, 0, XFS_B_TO_FSB(mp, pathlen), 0, NULL, 0,
                  mval, &nmaps, NULL, NULL);
      if (error)
            goto out;

      for (n = 0; n < nmaps; n++) {
            d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
            byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);

            bp = xfs_buf_read_flags(mp->m_ddev_targp, d, BTOBB(byte_cnt),
                              XBF_LOCK | XBF_MAPPED |
                              XBF_DONT_BLOCK);
            error = XFS_BUF_GETERROR(bp);
            if (error) {
                  xfs_ioerror_alert("xfs_readlink",
                          ip->i_mount, bp, XFS_BUF_ADDR(bp));
                  xfs_buf_relse(bp);
                  goto out;
            }
            if (pathlen < byte_cnt)
                  byte_cnt = pathlen;
            pathlen -= byte_cnt;

            memcpy(link, XFS_BUF_PTR(bp), byte_cnt);
            xfs_buf_relse(bp);
      }

      link[ip->i_d.di_size] = '\0';
      error = 0;

 out:
      return error;
}

int
xfs_readlink(
      xfs_inode_t     *ip,
      char        *link)
{
      xfs_mount_t *mp = ip->i_mount;
      int         pathlen;
      int         error = 0;

      xfs_itrace_entry(ip);

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      xfs_ilock(ip, XFS_ILOCK_SHARED);

      ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFLNK);
      ASSERT(ip->i_d.di_size <= MAXPATHLEN);

      pathlen = ip->i_d.di_size;
      if (!pathlen)
            goto out;

      if (ip->i_df.if_flags & XFS_IFINLINE) {
            memcpy(link, ip->i_df.if_u1.if_data, pathlen);
            link[pathlen] = '\0';
      } else {
            error = xfs_readlink_bmap(ip, link);
      }

 out:
      xfs_iunlock(ip, XFS_ILOCK_SHARED);
      return error;
}

/*
 * xfs_fsync
 *
 * This is called to sync the inode and its data out to disk.  We need to hold
 * the I/O lock while flushing the data, and the inode lock while flushing the
 * inode.  The inode lock CANNOT be held while flushing the data, so acquire
 * after we're done with that.
 */
int
xfs_fsync(
      xfs_inode_t *ip)
{
      xfs_trans_t *tp;
      int         error;
      int         log_flushed = 0, changed = 1;

      xfs_itrace_entry(ip);

      if (XFS_FORCED_SHUTDOWN(ip->i_mount))
            return XFS_ERROR(EIO);

      /* capture size updates in I/O completion before writing the inode. */
      error = xfs_wait_on_pages(ip, 0, -1);
      if (error)
            return XFS_ERROR(error);

      /*
       * We always need to make sure that the required inode state is safe on
       * disk.  The vnode might be clean but we still might need to force the
       * log because of committed transactions that haven't hit the disk yet.
       * Likewise, there could be unflushed non-transactional changes to the
       * inode core that have to go to disk and this requires us to issue
       * a synchronous transaction to capture these changes correctly.
       *
       * This code relies on the assumption that if the update_* fields
       * of the inode are clear and the inode is unpinned then it is clean
       * and no action is required.
       */
      xfs_ilock(ip, XFS_ILOCK_SHARED);

      if (!(ip->i_update_size || ip->i_update_core)) {
            /*
             * Timestamps/size haven't changed since last inode flush or
             * inode transaction commit.  That means either nothing got
             * written or a transaction committed which caught the updates.
             * If the latter happened and the transaction hasn't hit the
             * disk yet, the inode will be still be pinned.  If it is,
             * force the log.
             */

            xfs_iunlock(ip, XFS_ILOCK_SHARED);

            if (xfs_ipincount(ip)) {
                  error = _xfs_log_force(ip->i_mount, (xfs_lsn_t)0,
                              XFS_LOG_FORCE | XFS_LOG_SYNC,
                              &log_flushed);
            } else {
                  /*
                   * If the inode is not pinned and nothing has changed
                   * we don't need to flush the cache.
                   */
                  changed = 0;
            }
      } else      {
            /*
             * Kick off a transaction to log the inode core to get the
             * updates.  The sync transaction will also force the log.
             */
            xfs_iunlock(ip, XFS_ILOCK_SHARED);
            tp = xfs_trans_alloc(ip->i_mount, XFS_TRANS_FSYNC_TS);
            error = xfs_trans_reserve(tp, 0,
                        XFS_FSYNC_TS_LOG_RES(ip->i_mount), 0, 0, 0);
            if (error) {
                  xfs_trans_cancel(tp, 0);
                  return error;
            }
            xfs_ilock(ip, XFS_ILOCK_EXCL);

            /*
             * Note - it's possible that we might have pushed ourselves out
             * of the way during trans_reserve which would flush the inode.
             * But there's no guarantee that the inode buffer has actually
             * gone out yet (it's delwri).      Plus the buffer could be pinned
             * anyway if it's part of an inode in another recent
             * transaction.    So we play it safe and fire off the
             * transaction anyway.
             */
            xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
            xfs_trans_ihold(tp, ip);
            xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
            xfs_trans_set_sync(tp);
            error = _xfs_trans_commit(tp, 0, &log_flushed);

            xfs_iunlock(ip, XFS_ILOCK_EXCL);
      }

      if ((ip->i_mount->m_flags & XFS_MOUNT_BARRIER) && changed) {
            /*
             * If the log write didn't issue an ordered tag we need
             * to flush the disk cache for the data device now.
             */
            if (!log_flushed)
                  xfs_blkdev_issue_flush(ip->i_mount->m_ddev_targp);

            /*
             * If this inode is on the RT dev we need to flush that
             * cache as well.
             */
            if (XFS_IS_REALTIME_INODE(ip))
                  xfs_blkdev_issue_flush(ip->i_mount->m_rtdev_targp);
      }

      return error;
}

/*
 * This is called by xfs_inactive to free any blocks beyond eof
 * when the link count isn't zero and by xfs_dm_punch_hole() when
 * punching a hole to EOF.
 */
int
xfs_free_eofblocks(
      xfs_mount_t *mp,
      xfs_inode_t *ip,
      int         flags)
{
      xfs_trans_t *tp;
      int         error;
      xfs_fileoff_t     end_fsb;
      xfs_fileoff_t     last_fsb;
      xfs_filblks_t     map_len;
      int         nimaps;
      xfs_bmbt_irec_t   imap;
      int         use_iolock = (flags & XFS_FREE_EOF_LOCK);

      /*
       * Figure out if there are any blocks beyond the end
       * of the file.  If not, then there is nothing to do.
       */
      end_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)ip->i_size));
      last_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
      map_len = last_fsb - end_fsb;
      if (map_len <= 0)
            return 0;

      nimaps = 1;
      xfs_ilock(ip, XFS_ILOCK_SHARED);
      error = xfs_bmapi(NULL, ip, end_fsb, map_len, 0,
                    NULL, 0, &imap, &nimaps, NULL, NULL);
      xfs_iunlock(ip, XFS_ILOCK_SHARED);

      if (!error && (nimaps != 0) &&
          (imap.br_startblock != HOLESTARTBLOCK ||
           ip->i_delayed_blks)) {
            /*
             * Attach the dquots to the inode up front.
             */
            error = xfs_qm_dqattach(ip, 0);
            if (error)
                  return error;

            /*
             * There are blocks after the end of file.
             * Free them up now by truncating the file to
             * its current size.
             */
            tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);

            /*
             * Do the xfs_itruncate_start() call before
             * reserving any log space because
             * itruncate_start will call into the buffer
             * cache and we can't
             * do that within a transaction.
             */
            if (use_iolock)
                  xfs_ilock(ip, XFS_IOLOCK_EXCL);
            error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE,
                            ip->i_size);
            if (error) {
                  xfs_trans_cancel(tp, 0);
                  if (use_iolock)
                        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
                  return error;
            }

            error = xfs_trans_reserve(tp, 0,
                                XFS_ITRUNCATE_LOG_RES(mp),
                                0, XFS_TRANS_PERM_LOG_RES,
                                XFS_ITRUNCATE_LOG_COUNT);
            if (error) {
                  ASSERT(XFS_FORCED_SHUTDOWN(mp));
                  xfs_trans_cancel(tp, 0);
                  xfs_iunlock(ip, XFS_IOLOCK_EXCL);
                  return error;
            }

            xfs_ilock(ip, XFS_ILOCK_EXCL);
            xfs_trans_ijoin(tp, ip,
                        XFS_IOLOCK_EXCL |
                        XFS_ILOCK_EXCL);
            xfs_trans_ihold(tp, ip);

            error = xfs_itruncate_finish(&tp, ip,
                                   ip->i_size,
                                   XFS_DATA_FORK,
                                   0);
            /*
             * If we get an error at this point we
             * simply don't bother truncating the file.
             */
            if (error) {
                  xfs_trans_cancel(tp,
                               (XFS_TRANS_RELEASE_LOG_RES |
                                XFS_TRANS_ABORT));
            } else {
                  error = xfs_trans_commit(tp,
                                    XFS_TRANS_RELEASE_LOG_RES);
            }
            xfs_iunlock(ip, (use_iolock ? (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)
                                  : XFS_ILOCK_EXCL));
      }
      return error;
}

/*
 * Free a symlink that has blocks associated with it.
 */
STATIC int
xfs_inactive_symlink_rmt(
      xfs_inode_t *ip,
      xfs_trans_t **tpp)
{
      xfs_buf_t   *bp;
      int         committed;
      int         done;
      int         error;
      xfs_fsblock_t     first_block;
      xfs_bmap_free_t   free_list;
      int         i;
      xfs_mount_t *mp;
      xfs_bmbt_irec_t   mval[SYMLINK_MAPS];
      int         nmaps;
      xfs_trans_t *ntp;
      int         size;
      xfs_trans_t *tp;

      tp = *tpp;
      mp = ip->i_mount;
      ASSERT(ip->i_d.di_size > XFS_IFORK_DSIZE(ip));
      /*
       * We're freeing a symlink that has some
       * blocks allocated to it.  Free the
       * blocks here.  We know that we've got
       * either 1 or 2 extents and that we can
       * free them all in one bunmapi call.
       */
      ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
      if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
                  XFS_TRANS_PERM_LOG_RES, XFS_ITRUNCATE_LOG_COUNT))) {
            ASSERT(XFS_FORCED_SHUTDOWN(mp));
            xfs_trans_cancel(tp, 0);
            *tpp = NULL;
            return error;
      }
      /*
       * Lock the inode, fix the size, and join it to the transaction.
       * Hold it so in the normal path, we still have it locked for
       * the second transaction.  In the error paths we need it
       * held so the cancel won't rele it, see below.
       */
      xfs_ilock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
      size = (int)ip->i_d.di_size;
      ip->i_d.di_size = 0;
      xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
      xfs_trans_ihold(tp, ip);
      xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
      /*
       * Find the block(s) so we can inval and unmap them.
       */
      done = 0;
      xfs_bmap_init(&free_list, &first_block);
      nmaps = ARRAY_SIZE(mval);
      if ((error = xfs_bmapi(tp, ip, 0, XFS_B_TO_FSB(mp, size),
                  XFS_BMAPI_METADATA, &first_block, 0, mval, &nmaps,
                  &free_list, NULL)))
            goto error0;
      /*
       * Invalidate the block(s).
       */
      for (i = 0; i < nmaps; i++) {
            bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
                  XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
                  XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
            xfs_trans_binval(tp, bp);
      }
      /*
       * Unmap the dead block(s) to the free_list.
       */
      if ((error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps,
                  &first_block, &free_list, NULL, &done)))
            goto error1;
      ASSERT(done);
      /*
       * Commit the first transaction.  This logs the EFI and the inode.
       */
      if ((error = xfs_bmap_finish(&tp, &free_list, &committed)))
            goto error1;
      /*
       * The transaction must have been committed, since there were
       * actually extents freed by xfs_bunmapi.  See xfs_bmap_finish.
       * The new tp has the extent freeing and EFDs.
       */
      ASSERT(committed);
      /*
       * The first xact was committed, so add the inode to the new one.
       * Mark it dirty so it will be logged and moved forward in the log as
       * part of every commit.
       */
      xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
      xfs_trans_ihold(tp, ip);
      xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
      /*
       * Get a new, empty transaction to return to our caller.
       */
      ntp = xfs_trans_dup(tp);
      /*
       * Commit the transaction containing extent freeing and EFDs.
       * If we get an error on the commit here or on the reserve below,
       * we need to unlock the inode since the new transaction doesn't
       * have the inode attached.
       */
      error = xfs_trans_commit(tp, 0);
      tp = ntp;
      if (error) {
            ASSERT(XFS_FORCED_SHUTDOWN(mp));
            goto error0;
      }
      /*
       * transaction commit worked ok so we can drop the extra ticket
       * reference that we gained in xfs_trans_dup()
       */
      xfs_log_ticket_put(tp->t_ticket);

      /*
       * Remove the memory for extent descriptions (just bookkeeping).
       */
      if (ip->i_df.if_bytes)
            xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
      ASSERT(ip->i_df.if_bytes == 0);
      /*
       * Put an itruncate log reservation in the new transaction
       * for our caller.
       */
      if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
                  XFS_TRANS_PERM_LOG_RES, XFS_ITRUNCATE_LOG_COUNT))) {
            ASSERT(XFS_FORCED_SHUTDOWN(mp));
            goto error0;
      }
      /*
       * Return with the inode locked but not joined to the transaction.
       */
      *tpp = tp;
      return 0;

 error1:
      xfs_bmap_cancel(&free_list);
 error0:
      /*
       * Have to come here with the inode locked and either
       * (held and in the transaction) or (not in the transaction).
       * If the inode isn't held then cancel would iput it, but
       * that's wrong since this is inactive and the vnode ref
       * count is 0 already.
       * Cancel won't do anything to the inode if held, but it still
       * needs to be locked until the cancel is done, if it was
       * joined to the transaction.
       */
      xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
      xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
      *tpp = NULL;
      return error;

}

STATIC int
xfs_inactive_symlink_local(
      xfs_inode_t *ip,
      xfs_trans_t **tpp)
{
      int         error;

      ASSERT(ip->i_d.di_size <= XFS_IFORK_DSIZE(ip));
      /*
       * We're freeing a symlink which fit into
       * the inode.  Just free the memory used
       * to hold the old symlink.
       */
      error = xfs_trans_reserve(*tpp, 0,
                          XFS_ITRUNCATE_LOG_RES(ip->i_mount),
                          0, XFS_TRANS_PERM_LOG_RES,
                          XFS_ITRUNCATE_LOG_COUNT);

      if (error) {
            xfs_trans_cancel(*tpp, 0);
            *tpp = NULL;
            return error;
      }
      xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);

      /*
       * Zero length symlinks _can_ exist.
       */
      if (ip->i_df.if_bytes > 0) {
            xfs_idata_realloc(ip,
                          -(ip->i_df.if_bytes),
                          XFS_DATA_FORK);
            ASSERT(ip->i_df.if_bytes == 0);
      }
      return 0;
}

STATIC int
xfs_inactive_attrs(
      xfs_inode_t *ip,
      xfs_trans_t **tpp)
{
      xfs_trans_t *tp;
      int         error;
      xfs_mount_t *mp;

      ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
      tp = *tpp;
      mp = ip->i_mount;
      ASSERT(ip->i_d.di_forkoff != 0);
      error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
      xfs_iunlock(ip, XFS_ILOCK_EXCL);
      if (error)
            goto error_unlock;

      error = xfs_attr_inactive(ip);
      if (error)
            goto error_unlock;

      tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
      error = xfs_trans_reserve(tp, 0,
                          XFS_IFREE_LOG_RES(mp),
                          0, XFS_TRANS_PERM_LOG_RES,
                          XFS_INACTIVE_LOG_COUNT);
      if (error)
            goto error_cancel;

      xfs_ilock(ip, XFS_ILOCK_EXCL);
      xfs_trans_ijoin(tp, ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
      xfs_trans_ihold(tp, ip);
      xfs_idestroy_fork(ip, XFS_ATTR_FORK);

      ASSERT(ip->i_d.di_anextents == 0);

      *tpp = tp;
      return 0;

error_cancel:
      ASSERT(XFS_FORCED_SHUTDOWN(mp));
      xfs_trans_cancel(tp, 0);
error_unlock:
      *tpp = NULL;
      xfs_iunlock(ip, XFS_IOLOCK_EXCL);
      return error;
}

int
xfs_release(
      xfs_inode_t *ip)
{
      xfs_mount_t *mp = ip->i_mount;
      int         error;

      if (!S_ISREG(ip->i_d.di_mode) || (ip->i_d.di_mode == 0))
            return 0;

      /* If this is a read-only mount, don't do this (would generate I/O) */
      if (mp->m_flags & XFS_MOUNT_RDONLY)
            return 0;

      if (!XFS_FORCED_SHUTDOWN(mp)) {
            int truncated;

            /*
             * If we are using filestreams, and we have an unlinked
             * file that we are processing the last close on, then nothing
             * will be able to reopen and write to this file. Purge this
             * inode from the filestreams cache so that it doesn't delay
             * teardown of the inode.
             */
            if ((ip->i_d.di_nlink == 0) && xfs_inode_is_filestream(ip))
                  xfs_filestream_deassociate(ip);

            /*
             * If we previously truncated this file and removed old data
             * in the process, we want to initiate "early" writeout on
             * the last close.  This is an attempt to combat the notorious
             * NULL files problem which is particularly noticable from a
             * truncate down, buffered (re-)write (delalloc), followed by
             * a crash.  What we are effectively doing here is
             * significantly reducing the time window where we'd otherwise
             * be exposed to that problem.
             */
            truncated = xfs_iflags_test_and_clear(ip, XFS_ITRUNCATED);
            if (truncated && VN_DIRTY(VFS_I(ip)) && ip->i_delayed_blks > 0)
                  xfs_flush_pages(ip, 0, -1, XFS_B_ASYNC, FI_NONE);
      }

      if (ip->i_d.di_nlink != 0) {
            if ((((ip->i_d.di_mode & S_IFMT) == S_IFREG) &&
                 ((ip->i_size > 0) || (VN_CACHED(VFS_I(ip)) > 0 ||
                   ip->i_delayed_blks > 0)) &&
                 (ip->i_df.if_flags & XFS_IFEXTENTS))  &&
                (!(ip->i_d.di_flags &
                        (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))) {
                  error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);
                  if (error)
                        return error;
            }
      }

      return 0;
}

/*
 * xfs_inactive
 *
 * This is called when the vnode reference count for the vnode
 * goes to zero.  If the file has been unlinked, then it must
 * now be truncated.  Also, we clear all of the read-ahead state
 * kept for the inode here since the file is now closed.
 */
int
xfs_inactive(
      xfs_inode_t *ip)
{
      xfs_bmap_free_t   free_list;
      xfs_fsblock_t     first_block;
      int         committed;
      xfs_trans_t *tp;
      xfs_mount_t *mp;
      int         error;
      int         truncate;

      xfs_itrace_entry(ip);

      /*
       * If the inode is already free, then there can be nothing
       * to clean up here.
       */
      if (ip->i_d.di_mode == 0 || is_bad_inode(VFS_I(ip))) {
            ASSERT(ip->i_df.if_real_bytes == 0);
            ASSERT(ip->i_df.if_broot_bytes == 0);
            return VN_INACTIVE_CACHE;
      }

      /*
       * Only do a truncate if it's a regular file with
       * some actual space in it.  It's OK to look at the
       * inode's fields without the lock because we're the
       * only one with a reference to the inode.
       */
      truncate = ((ip->i_d.di_nlink == 0) &&
          ((ip->i_d.di_size != 0) || (ip->i_size != 0) ||
           (ip->i_d.di_nextents > 0) || (ip->i_delayed_blks > 0)) &&
          ((ip->i_d.di_mode & S_IFMT) == S_IFREG));

      mp = ip->i_mount;

      if (ip->i_d.di_nlink == 0 && DM_EVENT_ENABLED(ip, DM_EVENT_DESTROY))
            XFS_SEND_DESTROY(mp, ip, DM_RIGHT_NULL);

      error = 0;

      /* If this is a read-only mount, don't do this (would generate I/O) */
      if (mp->m_flags & XFS_MOUNT_RDONLY)
            goto out;

      if (ip->i_d.di_nlink != 0) {
            if ((((ip->i_d.di_mode & S_IFMT) == S_IFREG) &&
                     ((ip->i_size > 0) || (VN_CACHED(VFS_I(ip)) > 0 ||
                       ip->i_delayed_blks > 0)) &&
                  (ip->i_df.if_flags & XFS_IFEXTENTS) &&
                 (!(ip->i_d.di_flags &
                        (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) ||
                  (ip->i_delayed_blks != 0)))) {
                  error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);
                  if (error)
                        return VN_INACTIVE_CACHE;
            }
            goto out;
      }

      ASSERT(ip->i_d.di_nlink == 0);

      error = xfs_qm_dqattach(ip, 0);
      if (error)
            return VN_INACTIVE_CACHE;

      tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
      if (truncate) {
            /*
             * Do the xfs_itruncate_start() call before
             * reserving any log space because itruncate_start
             * will call into the buffer cache and we can't
             * do that within a transaction.
             */
            xfs_ilock(ip, XFS_IOLOCK_EXCL);

            error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, 0);
            if (error) {
                  xfs_trans_cancel(tp, 0);
                  xfs_iunlock(ip, XFS_IOLOCK_EXCL);
                  return VN_INACTIVE_CACHE;
            }

            error = xfs_trans_reserve(tp, 0,
                                XFS_ITRUNCATE_LOG_RES(mp),
                                0, XFS_TRANS_PERM_LOG_RES,
                                XFS_ITRUNCATE_LOG_COUNT);
            if (error) {
                  /* Don't call itruncate_cleanup */
                  ASSERT(XFS_FORCED_SHUTDOWN(mp));
                  xfs_trans_cancel(tp, 0);
                  xfs_iunlock(ip, XFS_IOLOCK_EXCL);
                  return VN_INACTIVE_CACHE;
            }

            xfs_ilock(ip, XFS_ILOCK_EXCL);
            xfs_trans_ijoin(tp, ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
            xfs_trans_ihold(tp, ip);

            /*
             * normally, we have to run xfs_itruncate_finish sync.
             * But if filesystem is wsync and we're in the inactive
             * path, then we know that nlink == 0, and that the
             * xaction that made nlink == 0 is permanently committed
             * since xfs_remove runs as a synchronous transaction.
             */
            error = xfs_itruncate_finish(&tp, ip, 0, XFS_DATA_FORK,
                        (!(mp->m_flags & XFS_MOUNT_WSYNC) ? 1 : 0));

            if (error) {
                  xfs_trans_cancel(tp,
                        XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
                  xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
                  return VN_INACTIVE_CACHE;
            }
      } else if ((ip->i_d.di_mode & S_IFMT) == S_IFLNK) {

            /*
             * If we get an error while cleaning up a
             * symlink we bail out.
             */
            error = (ip->i_d.di_size > XFS_IFORK_DSIZE(ip)) ?
                  xfs_inactive_symlink_rmt(ip, &tp) :
                  xfs_inactive_symlink_local(ip, &tp);

            if (error) {
                  ASSERT(tp == NULL);
                  return VN_INACTIVE_CACHE;
            }

            xfs_trans_ijoin(tp, ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
            xfs_trans_ihold(tp, ip);
      } else {
            error = xfs_trans_reserve(tp, 0,
                                XFS_IFREE_LOG_RES(mp),
                                0, XFS_TRANS_PERM_LOG_RES,
                                XFS_INACTIVE_LOG_COUNT);
            if (error) {
                  ASSERT(XFS_FORCED_SHUTDOWN(mp));
                  xfs_trans_cancel(tp, 0);
                  return VN_INACTIVE_CACHE;
            }

            xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
            xfs_trans_ijoin(tp, ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
            xfs_trans_ihold(tp, ip);
      }

      /*
       * If there are attributes associated with the file
       * then blow them away now.  The code calls a routine
       * that recursively deconstructs the attribute fork.
       * We need to just commit the current transaction
       * because we can't use it for xfs_attr_inactive().
       */
      if (ip->i_d.di_anextents > 0) {
            error = xfs_inactive_attrs(ip, &tp);
            /*
             * If we got an error, the transaction is already
             * cancelled, and the inode is unlocked. Just get out.
             */
             if (error)
                   return VN_INACTIVE_CACHE;
      } else if (ip->i_afp) {
            xfs_idestroy_fork(ip, XFS_ATTR_FORK);
      }

      /*
       * Free the inode.
       */
      xfs_bmap_init(&free_list, &first_block);
      error = xfs_ifree(tp, ip, &free_list);
      if (error) {
            /*
             * If we fail to free the inode, shut down.  The cancel
             * might do that, we need to make sure.  Otherwise the
             * inode might be lost for a long time or forever.
             */
            if (!XFS_FORCED_SHUTDOWN(mp)) {
                  cmn_err(CE_NOTE,
            "xfs_inactive:    xfs_ifree() returned an error = %d on %s",
                        error, mp->m_fsname);
                  xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
            }
            xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
      } else {
            /*
             * Credit the quota account(s). The inode is gone.
             */
            xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_ICOUNT, -1);

            /*
             * Just ignore errors at this point.  There is nothing we can
             * do except to try to keep going. Make sure it's not a silent
             * error.
             */
            error = xfs_bmap_finish(&tp,  &free_list, &committed);
            if (error)
                  xfs_fs_cmn_err(CE_NOTE, mp, "xfs_inactive: "
                        "xfs_bmap_finish() returned error %d", error);
            error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
            if (error)
                  xfs_fs_cmn_err(CE_NOTE, mp, "xfs_inactive: "
                        "xfs_trans_commit() returned error %d", error);
      }

      /*
       * Release the dquots held by inode, if any.
       */
      xfs_qm_dqdetach(ip);
      xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);

 out:
      return VN_INACTIVE_CACHE;
}

/*
 * Lookups up an inode from "name". If ci_name is not NULL, then a CI match
 * is allowed, otherwise it has to be an exact match. If a CI match is found,
 * ci_name->name will point to a the actual name (caller must free) or
 * will be set to NULL if an exact match is found.
 */
int
xfs_lookup(
      xfs_inode_t       *dp,
      struct xfs_name         *name,
      xfs_inode_t       **ipp,
      struct xfs_name         *ci_name)
{
      xfs_ino_t         inum;
      int               error;
      uint              lock_mode;

      xfs_itrace_entry(dp);

      if (XFS_FORCED_SHUTDOWN(dp->i_mount))
            return XFS_ERROR(EIO);

      lock_mode = xfs_ilock_map_shared(dp);
      error = xfs_dir_lookup(NULL, dp, name, &inum, ci_name);
      xfs_iunlock_map_shared(dp, lock_mode);

      if (error)
            goto out;

      error = xfs_iget(dp->i_mount, NULL, inum, 0, 0, ipp, 0);
      if (error)
            goto out_free_name;

      xfs_itrace_ref(*ipp);
      return 0;

out_free_name:
      if (ci_name)
            kmem_free(ci_name->name);
out:
      *ipp = NULL;
      return error;
}

int
xfs_create(
      xfs_inode_t       *dp,
      struct xfs_name         *name,
      mode_t                  mode,
      xfs_dev_t         rdev,
      xfs_inode_t       **ipp,
      cred_t                  *credp)
{
      int               is_dir = S_ISDIR(mode);
      struct xfs_mount  *mp = dp->i_mount;
      struct xfs_inode  *ip = NULL;
      struct xfs_trans  *tp = NULL;
      int               error;
      xfs_bmap_free_t         free_list;
      xfs_fsblock_t           first_block;
      boolean_t         unlock_dp_on_error = B_FALSE;
      uint              cancel_flags;
      int               committed;
      xfs_prid_t        prid;
      struct xfs_dquot  *udqp = NULL;
      struct xfs_dquot  *gdqp = NULL;
      uint              resblks;
      uint              log_res;
      uint              log_count;

      xfs_itrace_entry(dp);

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      if (DM_EVENT_ENABLED(dp, DM_EVENT_CREATE)) {
            error = XFS_SEND_NAMESP(mp, DM_EVENT_CREATE,
                        dp, DM_RIGHT_NULL, NULL,
                        DM_RIGHT_NULL, name->name, NULL,
                        mode, 0, 0);

            if (error)
                  return error;
      }

      if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
            prid = dp->i_d.di_projid;
      else
            prid = dfltprid;

      /*
       * Make sure that we have allocated dquot(s) on disk.
       */
      error = xfs_qm_vop_dqalloc(dp, current_fsuid(), current_fsgid(), prid,
                  XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp);
      if (error)
            goto std_return;

      if (is_dir) {
            rdev = 0;
            resblks = XFS_MKDIR_SPACE_RES(mp, name->len);
            log_res = XFS_MKDIR_LOG_RES(mp);
            log_count = XFS_MKDIR_LOG_COUNT;
            tp = xfs_trans_alloc(mp, XFS_TRANS_MKDIR);
      } else {
            resblks = XFS_CREATE_SPACE_RES(mp, name->len);
            log_res = XFS_CREATE_LOG_RES(mp);
            log_count = XFS_CREATE_LOG_COUNT;
            tp = xfs_trans_alloc(mp, XFS_TRANS_CREATE);
      }

      cancel_flags = XFS_TRANS_RELEASE_LOG_RES;

      /*
       * Initially assume that the file does not exist and
       * reserve the resources for that case.  If that is not
       * the case we'll drop the one we have and get a more
       * appropriate transaction later.
       */
      error = xfs_trans_reserve(tp, resblks, log_res, 0,
                  XFS_TRANS_PERM_LOG_RES, log_count);
      if (error == ENOSPC) {
            /* flush outstanding delalloc blocks and retry */
            xfs_flush_inodes(dp);
            error = xfs_trans_reserve(tp, resblks, XFS_CREATE_LOG_RES(mp), 0,
                  XFS_TRANS_PERM_LOG_RES, XFS_CREATE_LOG_COUNT);
      }
      if (error == ENOSPC) {
            /* No space at all so try a "no-allocation" reservation */
            resblks = 0;
            error = xfs_trans_reserve(tp, 0, log_res, 0,
                        XFS_TRANS_PERM_LOG_RES, log_count);
      }
      if (error) {
            cancel_flags = 0;
            goto out_trans_cancel;
      }

      xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
      unlock_dp_on_error = B_TRUE;

      /*
       * Check for directory link count overflow.
       */
      if (is_dir && dp->i_d.di_nlink >= XFS_MAXLINK) {
            error = XFS_ERROR(EMLINK);
            goto out_trans_cancel;
      }

      xfs_bmap_init(&free_list, &first_block);

      /*
       * Reserve disk quota and the inode.
       */
      error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, resblks, 1, 0);
      if (error)
            goto out_trans_cancel;

      error = xfs_dir_canenter(tp, dp, name, resblks);
      if (error)
            goto out_trans_cancel;

      /*
       * A newly created regular or special file just has one directory
       * entry pointing to them, but a directory also the "." entry
       * pointing to itself.
       */
      error = xfs_dir_ialloc(&tp, dp, mode, is_dir ? 2 : 1, rdev, credp,
                         prid, resblks > 0, &ip, &committed);
      if (error) {
            if (error == ENOSPC)
                  goto out_trans_cancel;
            goto out_trans_abort;
      }

      /*
       * At this point, we've gotten a newly allocated inode.
       * It is locked (and joined to the transaction).
       */
      xfs_itrace_ref(ip);
      ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));

      /*
       * Now we join the directory inode to the transaction.  We do not do it
       * earlier because xfs_dir_ialloc might commit the previous transaction
       * (and release all the locks).  An error from here on will result in
       * the transaction cancel unlocking dp so don't do it explicitly in the
       * error path.
       */
      IHOLD(dp);
      xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
      unlock_dp_on_error = B_FALSE;

      error = xfs_dir_createname(tp, dp, name, ip->i_ino,
                              &first_block, &free_list, resblks ?
                              resblks - XFS_IALLOC_SPACE_RES(mp) : 0);
      if (error) {
            ASSERT(error != ENOSPC);
            goto out_trans_abort;
      }
      xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
      xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);

      if (is_dir) {
            error = xfs_dir_init(tp, ip, dp);
            if (error)
                  goto out_bmap_cancel;

            error = xfs_bumplink(tp, dp);
            if (error)
                  goto out_bmap_cancel;
      }

      /*
       * If this is a synchronous mount, make sure that the
       * create transaction goes to disk before returning to
       * the user.
       */
      if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC))
            xfs_trans_set_sync(tp);

      /*
       * Attach the dquot(s) to the inodes and modify them incore.
       * These ids of the inode couldn't have changed since the new
       * inode has been locked ever since it was created.
       */
      xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp);

      /*
       * xfs_trans_commit normally decrements the vnode ref count
       * when it unlocks the inode. Since we want to return the
       * vnode to the caller, we bump the vnode ref count now.
       */
      IHOLD(ip);

      error = xfs_bmap_finish(&tp, &free_list, &committed);
      if (error)
            goto out_abort_rele;

      error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
      if (error) {
            IRELE(ip);
            goto out_dqrele;
      }

      xfs_qm_dqrele(udqp);
      xfs_qm_dqrele(gdqp);

      *ipp = ip;

      /* Fallthrough to std_return with error = 0  */
 std_return:
      if (DM_EVENT_ENABLED(dp, DM_EVENT_POSTCREATE)) {
            XFS_SEND_NAMESP(mp, DM_EVENT_POSTCREATE, dp, DM_RIGHT_NULL,
                        ip, DM_RIGHT_NULL, name->name, NULL, mode,
                        error, 0);
      }

      return error;

 out_bmap_cancel:
      xfs_bmap_cancel(&free_list);
 out_trans_abort:
      cancel_flags |= XFS_TRANS_ABORT;
 out_trans_cancel:
      xfs_trans_cancel(tp, cancel_flags);
 out_dqrele:
      xfs_qm_dqrele(udqp);
      xfs_qm_dqrele(gdqp);

      if (unlock_dp_on_error)
            xfs_iunlock(dp, XFS_ILOCK_EXCL);

      goto std_return;

 out_abort_rele:
      /*
       * Wait until after the current transaction is aborted to
       * release the inode.  This prevents recursive transactions
       * and deadlocks from xfs_inactive.
       */
      xfs_bmap_cancel(&free_list);
      cancel_flags |= XFS_TRANS_ABORT;
      xfs_trans_cancel(tp, cancel_flags);
      IRELE(ip);
      unlock_dp_on_error = B_FALSE;
      goto out_dqrele;
}

#ifdef DEBUG
int xfs_locked_n;
int xfs_small_retries;
int xfs_middle_retries;
int xfs_lots_retries;
int xfs_lock_delays;
#endif

/*
 * Bump the subclass so xfs_lock_inodes() acquires each lock with
 * a different value
 */
static inline int
xfs_lock_inumorder(int lock_mode, int subclass)
{
      if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL))
            lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_IOLOCK_SHIFT;
      if (lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL))
            lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_ILOCK_SHIFT;

      return lock_mode;
}

/*
 * The following routine will lock n inodes in exclusive mode.
 * We assume the caller calls us with the inodes in i_ino order.
 *
 * We need to detect deadlock where an inode that we lock
 * is in the AIL and we start waiting for another inode that is locked
 * by a thread in a long running transaction (such as truncate). This can
 * result in deadlock since the long running trans might need to wait
 * for the inode we just locked in order to push the tail and free space
 * in the log.
 */
void
xfs_lock_inodes(
      xfs_inode_t **ips,
      int         inodes,
      uint        lock_mode)
{
      int         attempts = 0, i, j, try_lock;
      xfs_log_item_t    *lp;

      ASSERT(ips && (inodes >= 2)); /* we need at least two */

      try_lock = 0;
      i = 0;

again:
      for (; i < inodes; i++) {
            ASSERT(ips[i]);

            if (i && (ips[i] == ips[i-1]))      /* Already locked */
                  continue;

            /*
             * If try_lock is not set yet, make sure all locked inodes
             * are not in the AIL.
             * If any are, set try_lock to be used later.
             */

            if (!try_lock) {
                  for (j = (i - 1); j >= 0 && !try_lock; j--) {
                        lp = (xfs_log_item_t *)ips[j]->i_itemp;
                        if (lp && (lp->li_flags & XFS_LI_IN_AIL)) {
                              try_lock++;
                        }
                  }
            }

            /*
             * If any of the previous locks we have locked is in the AIL,
             * we must TRY to get the second and subsequent locks. If
             * we can't get any, we must release all we have
             * and try again.
             */

            if (try_lock) {
                  /* try_lock must be 0 if i is 0. */
                  /*
                   * try_lock means we have an inode locked
                   * that is in the AIL.
                   */
                  ASSERT(i != 0);
                  if (!xfs_ilock_nowait(ips[i], xfs_lock_inumorder(lock_mode, i))) {
                        attempts++;

                        /*
                         * Unlock all previous guys and try again.
                         * xfs_iunlock will try to push the tail
                         * if the inode is in the AIL.
                         */

                        for(j = i - 1; j >= 0; j--) {

                              /*
                               * Check to see if we've already
                               * unlocked this one.
                               * Not the first one going back,
                               * and the inode ptr is the same.
                               */
                              if ((j != (i - 1)) && ips[j] ==
                                                ips[j+1])
                                    continue;

                              xfs_iunlock(ips[j], lock_mode);
                        }

                        if ((attempts % 5) == 0) {
                              delay(1); /* Don't just spin the CPU */
#ifdef DEBUG
                              xfs_lock_delays++;
#endif
                        }
                        i = 0;
                        try_lock = 0;
                        goto again;
                  }
            } else {
                  xfs_ilock(ips[i], xfs_lock_inumorder(lock_mode, i));
            }
      }

#ifdef DEBUG
      if (attempts) {
            if (attempts < 5) xfs_small_retries++;
            else if (attempts < 100) xfs_middle_retries++;
            else xfs_lots_retries++;
      } else {
            xfs_locked_n++;
      }
#endif
}

/*
 * xfs_lock_two_inodes() can only be used to lock one type of lock
 * at a time - the iolock or the ilock, but not both at once. If
 * we lock both at once, lockdep will report false positives saying
 * we have violated locking orders.
 */
void
xfs_lock_two_inodes(
      xfs_inode_t       *ip0,
      xfs_inode_t       *ip1,
      uint              lock_mode)
{
      xfs_inode_t       *temp;
      int               attempts = 0;
      xfs_log_item_t          *lp;

      if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL))
            ASSERT((lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)) == 0);
      ASSERT(ip0->i_ino != ip1->i_ino);

      if (ip0->i_ino > ip1->i_ino) {
            temp = ip0;
            ip0 = ip1;
            ip1 = temp;
      }

 again:
      xfs_ilock(ip0, xfs_lock_inumorder(lock_mode, 0));

      /*
       * If the first lock we have locked is in the AIL, we must TRY to get
       * the second lock. If we can't get it, we must release the first one
       * and try again.
       */
      lp = (xfs_log_item_t *)ip0->i_itemp;
      if (lp && (lp->li_flags & XFS_LI_IN_AIL)) {
            if (!xfs_ilock_nowait(ip1, xfs_lock_inumorder(lock_mode, 1))) {
                  xfs_iunlock(ip0, lock_mode);
                  if ((++attempts % 5) == 0)
                        delay(1); /* Don't just spin the CPU */
                  goto again;
            }
      } else {
            xfs_ilock(ip1, xfs_lock_inumorder(lock_mode, 1));
      }
}

int
xfs_remove(
      xfs_inode_t             *dp,
      struct xfs_name         *name,
      xfs_inode_t       *ip)
{
      xfs_mount_t       *mp = dp->i_mount;
      xfs_trans_t             *tp = NULL;
      int               is_dir = S_ISDIR(ip->i_d.di_mode);
      int                     error = 0;
      xfs_bmap_free_t         free_list;
      xfs_fsblock_t           first_block;
      int               cancel_flags;
      int               committed;
      int               link_zero;
      uint              resblks;
      uint              log_count;

      xfs_itrace_entry(dp);
      xfs_itrace_entry(ip);

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      if (DM_EVENT_ENABLED(dp, DM_EVENT_REMOVE)) {
            error = XFS_SEND_NAMESP(mp, DM_EVENT_REMOVE, dp, DM_RIGHT_NULL,
                              NULL, DM_RIGHT_NULL, name->name, NULL,
                              ip->i_d.di_mode, 0, 0);
            if (error)
                  return error;
      }

      error = xfs_qm_dqattach(dp, 0);
      if (error)
            goto std_return;

      error = xfs_qm_dqattach(ip, 0);
      if (error)
            goto std_return;

      if (is_dir) {
            tp = xfs_trans_alloc(mp, XFS_TRANS_RMDIR);
            log_count = XFS_DEFAULT_LOG_COUNT;
      } else {
            tp = xfs_trans_alloc(mp, XFS_TRANS_REMOVE);
            log_count = XFS_REMOVE_LOG_COUNT;
      }
      cancel_flags = XFS_TRANS_RELEASE_LOG_RES;

      /*
       * We try to get the real space reservation first,
       * allowing for directory btree deletion(s) implying
       * possible bmap insert(s).  If we can't get the space
       * reservation then we use 0 instead, and avoid the bmap
       * btree insert(s) in the directory code by, if the bmap
       * insert tries to happen, instead trimming the LAST
       * block from the directory.
       */
      resblks = XFS_REMOVE_SPACE_RES(mp);
      error = xfs_trans_reserve(tp, resblks, XFS_REMOVE_LOG_RES(mp), 0,
                          XFS_TRANS_PERM_LOG_RES, log_count);
      if (error == ENOSPC) {
            resblks = 0;
            error = xfs_trans_reserve(tp, 0, XFS_REMOVE_LOG_RES(mp), 0,
                                XFS_TRANS_PERM_LOG_RES, log_count);
      }
      if (error) {
            ASSERT(error != ENOSPC);
            cancel_flags = 0;
            goto out_trans_cancel;
      }

      xfs_lock_two_inodes(dp, ip, XFS_ILOCK_EXCL);

      /*
       * At this point, we've gotten both the directory and the entry
       * inodes locked.
       */
      IHOLD(ip);
      xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);

      IHOLD(dp);
      xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);

      /*
       * If we're removing a directory perform some additional validation.
       */
      if (is_dir) {
            ASSERT(ip->i_d.di_nlink >= 2);
            if (ip->i_d.di_nlink != 2) {
                  error = XFS_ERROR(ENOTEMPTY);
                  goto out_trans_cancel;
            }
            if (!xfs_dir_isempty(ip)) {
                  error = XFS_ERROR(ENOTEMPTY);
                  goto out_trans_cancel;
            }
      }

      xfs_bmap_init(&free_list, &first_block);
      error = xfs_dir_removename(tp, dp, name, ip->i_ino,
                              &first_block, &free_list, resblks);
      if (error) {
            ASSERT(error != ENOENT);
            goto out_bmap_cancel;
      }
      xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);

      if (is_dir) {
            /*
             * Drop the link from ip's "..".
             */
            error = xfs_droplink(tp, dp);
            if (error)
                  goto out_bmap_cancel;

            /*
             * Drop the "." link from ip to self.
             */
            error = xfs_droplink(tp, ip);
            if (error)
                  goto out_bmap_cancel;
      } else {
            /*
             * When removing a non-directory we need to log the parent
             * inode here.  For a directory this is done implicitly
             * by the xfs_droplink call for the ".." entry.
             */
            xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
      }

      /*
       * Drop the link from dp to ip.
       */
      error = xfs_droplink(tp, ip);
      if (error)
            goto out_bmap_cancel;

      /*
       * Determine if this is the last link while
       * we are in the transaction.
       */
      link_zero = (ip->i_d.di_nlink == 0);

      /*
       * If this is a synchronous mount, make sure that the
       * remove transaction goes to disk before returning to
       * the user.
       */
      if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC))
            xfs_trans_set_sync(tp);

      error = xfs_bmap_finish(&tp, &free_list, &committed);
      if (error)
            goto out_bmap_cancel;

      error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
      if (error)
            goto std_return;

      /*
       * If we are using filestreams, kill the stream association.
       * If the file is still open it may get a new one but that
       * will get killed on last close in xfs_close() so we don't
       * have to worry about that.
       */
      if (!is_dir && link_zero && xfs_inode_is_filestream(ip))
            xfs_filestream_deassociate(ip);

      xfs_itrace_exit(ip);
      xfs_itrace_exit(dp);

 std_return:
      if (DM_EVENT_ENABLED(dp, DM_EVENT_POSTREMOVE)) {
            XFS_SEND_NAMESP(mp, DM_EVENT_POSTREMOVE, dp, DM_RIGHT_NULL,
                        NULL, DM_RIGHT_NULL, name->name, NULL,
                        ip->i_d.di_mode, error, 0);
      }

      return error;

 out_bmap_cancel:
      xfs_bmap_cancel(&free_list);
      cancel_flags |= XFS_TRANS_ABORT;
 out_trans_cancel:
      xfs_trans_cancel(tp, cancel_flags);
      goto std_return;
}

int
xfs_link(
      xfs_inode_t       *tdp,
      xfs_inode_t       *sip,
      struct xfs_name         *target_name)
{
      xfs_mount_t       *mp = tdp->i_mount;
      xfs_trans_t       *tp;
      int               error;
      xfs_bmap_free_t         free_list;
      xfs_fsblock_t           first_block;
      int               cancel_flags;
      int               committed;
      int               resblks;

      xfs_itrace_entry(tdp);
      xfs_itrace_entry(sip);

      ASSERT(!S_ISDIR(sip->i_d.di_mode));

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      if (DM_EVENT_ENABLED(tdp, DM_EVENT_LINK)) {
            error = XFS_SEND_NAMESP(mp, DM_EVENT_LINK,
                              tdp, DM_RIGHT_NULL,
                              sip, DM_RIGHT_NULL,
                              target_name->name, NULL, 0, 0, 0);
            if (error)
                  return error;
      }

      /* Return through std_return after this point. */

      error = xfs_qm_dqattach(sip, 0);
      if (error)
            goto std_return;

      error = xfs_qm_dqattach(tdp, 0);
      if (error)
            goto std_return;

      tp = xfs_trans_alloc(mp, XFS_TRANS_LINK);
      cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
      resblks = XFS_LINK_SPACE_RES(mp, target_name->len);
      error = xfs_trans_reserve(tp, resblks, XFS_LINK_LOG_RES(mp), 0,
                  XFS_TRANS_PERM_LOG_RES, XFS_LINK_LOG_COUNT);
      if (error == ENOSPC) {
            resblks = 0;
            error = xfs_trans_reserve(tp, 0, XFS_LINK_LOG_RES(mp), 0,
                        XFS_TRANS_PERM_LOG_RES, XFS_LINK_LOG_COUNT);
      }
      if (error) {
            cancel_flags = 0;
            goto error_return;
      }

      xfs_lock_two_inodes(sip, tdp, XFS_ILOCK_EXCL);

      /*
       * Increment vnode ref counts since xfs_trans_commit &
       * xfs_trans_cancel will both unlock the inodes and
       * decrement the associated ref counts.
       */
      IHOLD(sip);
      IHOLD(tdp);
      xfs_trans_ijoin(tp, sip, XFS_ILOCK_EXCL);
      xfs_trans_ijoin(tp, tdp, XFS_ILOCK_EXCL);

      /*
       * If the source has too many links, we can't make any more to it.
       */
      if (sip->i_d.di_nlink >= XFS_MAXLINK) {
            error = XFS_ERROR(EMLINK);
            goto error_return;
      }

      /*
       * If we are using project inheritance, we only allow hard link
       * creation in our tree when the project IDs are the same; else
       * the tree quota mechanism could be circumvented.
       */
      if (unlikely((tdp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
                 (tdp->i_d.di_projid != sip->i_d.di_projid))) {
            error = XFS_ERROR(EXDEV);
            goto error_return;
      }

      error = xfs_dir_canenter(tp, tdp, target_name, resblks);
      if (error)
            goto error_return;

      xfs_bmap_init(&free_list, &first_block);

      error = xfs_dir_createname(tp, tdp, target_name, sip->i_ino,
                              &first_block, &free_list, resblks);
      if (error)
            goto abort_return;
      xfs_ichgtime(tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
      xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);

      error = xfs_bumplink(tp, sip);
      if (error)
            goto abort_return;

      /*
       * If this is a synchronous mount, make sure that the
       * link transaction goes to disk before returning to
       * the user.
       */
      if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
            xfs_trans_set_sync(tp);
      }

      error = xfs_bmap_finish (&tp, &free_list, &committed);
      if (error) {
            xfs_bmap_cancel(&free_list);
            goto abort_return;
      }

      error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
      if (error)
            goto std_return;

      /* Fall through to std_return with error = 0. */
std_return:
      if (DM_EVENT_ENABLED(sip, DM_EVENT_POSTLINK)) {
            (void) XFS_SEND_NAMESP(mp, DM_EVENT_POSTLINK,
                        tdp, DM_RIGHT_NULL,
                        sip, DM_RIGHT_NULL,
                        target_name->name, NULL, 0, error, 0);
      }
      return error;

 abort_return:
      cancel_flags |= XFS_TRANS_ABORT;
      /* FALLTHROUGH */

 error_return:
      xfs_trans_cancel(tp, cancel_flags);
      goto std_return;
}

int
xfs_symlink(
      xfs_inode_t       *dp,
      struct xfs_name         *link_name,
      const char        *target_path,
      mode_t                  mode,
      xfs_inode_t       **ipp,
      cred_t                  *credp)
{
      xfs_mount_t       *mp = dp->i_mount;
      xfs_trans_t       *tp;
      xfs_inode_t       *ip;
      int               error;
      int               pathlen;
      xfs_bmap_free_t         free_list;
      xfs_fsblock_t           first_block;
      boolean_t         unlock_dp_on_error = B_FALSE;
      uint              cancel_flags;
      int               committed;
      xfs_fileoff_t           first_fsb;
      xfs_filblks_t           fs_blocks;
      int               nmaps;
      xfs_bmbt_irec_t         mval[SYMLINK_MAPS];
      xfs_daddr_t       d;
      const char        *cur_chunk;
      int               byte_cnt;
      int               n;
      xfs_buf_t         *bp;
      xfs_prid_t        prid;
      struct xfs_dquot  *udqp, *gdqp;
      uint              resblks;

      *ipp = NULL;
      error = 0;
      ip = NULL;
      tp = NULL;

      xfs_itrace_entry(dp);

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      /*
       * Check component lengths of the target path name.
       */
      pathlen = strlen(target_path);
      if (pathlen >= MAXPATHLEN)      /* total string too long */
            return XFS_ERROR(ENAMETOOLONG);

      if (DM_EVENT_ENABLED(dp, DM_EVENT_SYMLINK)) {
            error = XFS_SEND_NAMESP(mp, DM_EVENT_SYMLINK, dp,
                              DM_RIGHT_NULL, NULL, DM_RIGHT_NULL,
                              link_name->name, target_path, 0, 0, 0);
            if (error)
                  return error;
      }

      /* Return through std_return after this point. */

      udqp = gdqp = NULL;
      if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
            prid = dp->i_d.di_projid;
      else
            prid = (xfs_prid_t)dfltprid;

      /*
       * Make sure that we have allocated dquot(s) on disk.
       */
      error = xfs_qm_vop_dqalloc(dp, current_fsuid(), current_fsgid(), prid,
                  XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp);
      if (error)
            goto std_return;

      tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
      cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
      /*
       * The symlink will fit into the inode data fork?
       * There can't be any attributes so we get the whole variable part.
       */
      if (pathlen <= XFS_LITINO(mp))
            fs_blocks = 0;
      else
            fs_blocks = XFS_B_TO_FSB(mp, pathlen);
      resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
      error = xfs_trans_reserve(tp, resblks, XFS_SYMLINK_LOG_RES(mp), 0,
                  XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
      if (error == ENOSPC && fs_blocks == 0) {
            resblks = 0;
            error = xfs_trans_reserve(tp, 0, XFS_SYMLINK_LOG_RES(mp), 0,
                        XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
      }
      if (error) {
            cancel_flags = 0;
            goto error_return;
      }

      xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
      unlock_dp_on_error = B_TRUE;

      /*
       * Check whether the directory allows new symlinks or not.
       */
      if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
            error = XFS_ERROR(EPERM);
            goto error_return;
      }

      /*
       * Reserve disk quota : blocks and inode.
       */
      error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, resblks, 1, 0);
      if (error)
            goto error_return;

      /*
       * Check for ability to enter directory entry, if no space reserved.
       */
      error = xfs_dir_canenter(tp, dp, link_name, resblks);
      if (error)
            goto error_return;
      /*
       * Initialize the bmap freelist prior to calling either
       * bmapi or the directory create code.
       */
      xfs_bmap_init(&free_list, &first_block);

      /*
       * Allocate an inode for the symlink.
       */
      error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT),
                         1, 0, credp, prid, resblks > 0, &ip, NULL);
      if (error) {
            if (error == ENOSPC)
                  goto error_return;
            goto error1;
      }
      xfs_itrace_ref(ip);

      /*
       * An error after we've joined dp to the transaction will result in the
       * transaction cancel unlocking dp so don't do it explicitly in the
       * error path.
       */
      IHOLD(dp);
      xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
      unlock_dp_on_error = B_FALSE;

      /*
       * Also attach the dquot(s) to it, if applicable.
       */
      xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp);

      if (resblks)
            resblks -= XFS_IALLOC_SPACE_RES(mp);
      /*
       * If the symlink will fit into the inode, write it inline.
       */
      if (pathlen <= XFS_IFORK_DSIZE(ip)) {
            xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
            memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
            ip->i_d.di_size = pathlen;

            /*
             * The inode was initially created in extent format.
             */
            ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
            ip->i_df.if_flags |= XFS_IFINLINE;

            ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
            xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);

      } else {
            first_fsb = 0;
            nmaps = SYMLINK_MAPS;

            error = xfs_bmapi(tp, ip, first_fsb, fs_blocks,
                          XFS_BMAPI_WRITE | XFS_BMAPI_METADATA,
                          &first_block, resblks, mval, &nmaps,
                          &free_list, NULL);
            if (error) {
                  goto error1;
            }

            if (resblks)
                  resblks -= fs_blocks;
            ip->i_d.di_size = pathlen;
            xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

            cur_chunk = target_path;
            for (n = 0; n < nmaps; n++) {
                  d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
                  byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
                  bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
                                     BTOBB(byte_cnt), 0);
                  ASSERT(bp && !XFS_BUF_GETERROR(bp));
                  if (pathlen < byte_cnt) {
                        byte_cnt = pathlen;
                  }
                  pathlen -= byte_cnt;

                  memcpy(XFS_BUF_PTR(bp), cur_chunk, byte_cnt);
                  cur_chunk += byte_cnt;

                  xfs_trans_log_buf(tp, bp, 0, byte_cnt - 1);
            }
      }

      /*
       * Create the directory entry for the symlink.
       */
      error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
                              &first_block, &free_list, resblks);
      if (error)
            goto error1;
      xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
      xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);

      /*
       * If this is a synchronous mount, make sure that the
       * symlink transaction goes to disk before returning to
       * the user.
       */
      if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
            xfs_trans_set_sync(tp);
      }

      /*
       * xfs_trans_commit normally decrements the vnode ref count
       * when it unlocks the inode. Since we want to return the
       * vnode to the caller, we bump the vnode ref count now.
       */
      IHOLD(ip);

      error = xfs_bmap_finish(&tp, &free_list, &committed);
      if (error) {
            goto error2;
      }
      error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
      xfs_qm_dqrele(udqp);
      xfs_qm_dqrele(gdqp);

      /* Fall through to std_return with error = 0 or errno from
       * xfs_trans_commit     */
std_return:
      if (DM_EVENT_ENABLED(dp, DM_EVENT_POSTSYMLINK)) {
            (void) XFS_SEND_NAMESP(mp, DM_EVENT_POSTSYMLINK,
                              dp, DM_RIGHT_NULL,
                              error ? NULL : ip,
                              DM_RIGHT_NULL, link_name->name,
                              target_path, 0, error, 0);
      }

      if (!error)
            *ipp = ip;
      return error;

 error2:
      IRELE(ip);
 error1:
      xfs_bmap_cancel(&free_list);
      cancel_flags |= XFS_TRANS_ABORT;
 error_return:
      xfs_trans_cancel(tp, cancel_flags);
      xfs_qm_dqrele(udqp);
      xfs_qm_dqrele(gdqp);

      if (unlock_dp_on_error)
            xfs_iunlock(dp, XFS_ILOCK_EXCL);

      goto std_return;
}

int
xfs_set_dmattrs(
      xfs_inode_t     *ip,
      u_int       evmask,
      u_int16_t   state)
{
      xfs_mount_t *mp = ip->i_mount;
      xfs_trans_t *tp;
      int         error;

      if (!capable(CAP_SYS_ADMIN))
            return XFS_ERROR(EPERM);

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      tp = xfs_trans_alloc(mp, XFS_TRANS_SET_DMATTRS);
      error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES (mp), 0, 0, 0);
      if (error) {
            xfs_trans_cancel(tp, 0);
            return error;
      }
      xfs_ilock(ip, XFS_ILOCK_EXCL);
      xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);

      ip->i_d.di_dmevmask = evmask;
      ip->i_d.di_dmstate  = state;

      xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
      IHOLD(ip);
      error = xfs_trans_commit(tp, 0);

      return error;
}

int
xfs_reclaim(
      xfs_inode_t *ip)
{

      xfs_itrace_entry(ip);

      ASSERT(!VN_MAPPED(VFS_I(ip)));

      /* bad inode, get out here ASAP */
      if (is_bad_inode(VFS_I(ip))) {
            xfs_ireclaim(ip);
            return 0;
      }

      xfs_ioend_wait(ip);

      ASSERT(XFS_FORCED_SHUTDOWN(ip->i_mount) || ip->i_delayed_blks == 0);

      /*
       * Make sure the atime in the XFS inode is correct before freeing the
       * Linux inode.
       */
      xfs_synchronize_atime(ip);

      /*
       * If we have nothing to flush with this inode then complete the
       * teardown now, otherwise break the link between the xfs inode and the
       * linux inode and clean up the xfs inode later. This avoids flushing
       * the inode to disk during the delete operation itself.
       *
       * When breaking the link, we need to set the XFS_IRECLAIMABLE flag
       * first to ensure that xfs_iunpin() will never see an xfs inode
       * that has a linux inode being reclaimed. Synchronisation is provided
       * by the i_flags_lock.
       */
      if (!ip->i_update_core && (ip->i_itemp == NULL)) {
            xfs_ilock(ip, XFS_ILOCK_EXCL);
            xfs_iflock(ip);
            xfs_iflags_set(ip, XFS_IRECLAIMABLE);
            return xfs_reclaim_inode(ip, 1, XFS_IFLUSH_DELWRI_ELSE_SYNC);
      }
      xfs_inode_set_reclaim_tag(ip);
      return 0;
}

/*
 * xfs_alloc_file_space()
 *      This routine allocates disk space for the given file.
 *
 *    If alloc_type == 0, this request is for an ALLOCSP type
 *    request which will change the file size.  In this case, no
 *    DMAPI event will be generated by the call.  A TRUNCATE event
 *    will be generated later by xfs_setattr.
 *
 *    If alloc_type != 0, this request is for a RESVSP type
 *    request, and a DMAPI DM_EVENT_WRITE will be generated if the
 *    lower block boundary byte address is less than the file's
 *    length.
 *
 * RETURNS:
 *       0 on success
 *      errno on error
 *
 */
STATIC int
xfs_alloc_file_space(
      xfs_inode_t       *ip,
      xfs_off_t         offset,
      xfs_off_t         len,
      int               alloc_type,
      int               attr_flags)
{
      xfs_mount_t       *mp = ip->i_mount;
      xfs_off_t         count;
      xfs_filblks_t           allocated_fsb;
      xfs_filblks_t           allocatesize_fsb;
      xfs_extlen_t            extsz, temp;
      xfs_fileoff_t           startoffset_fsb;
      xfs_fsblock_t           firstfsb;
      int               nimaps;
      int               bmapi_flag;
      int               quota_flag;
      int               rt;
      xfs_trans_t       *tp;
      xfs_bmbt_irec_t         imaps[1], *imapp;
      xfs_bmap_free_t         free_list;
      uint              qblocks, resblks, resrtextents;
      int               committed;
      int               error;

      xfs_itrace_entry(ip);

      if (XFS_FORCED_SHUTDOWN(mp))
            return XFS_ERROR(EIO);

      error = xfs_qm_dqattach(ip, 0);
      if (error)
            return error;

      if (len <= 0)
            return XFS_ERROR(EINVAL);

      rt = XFS_IS_REALTIME_INODE(ip);
      extsz = xfs_get_extsz_hint(ip);

      count = len;
      imapp = &imaps[0];
      nimaps = 1;
      bmapi_flag = XFS_BMAPI_WRITE | (alloc_type ? XFS_BMAPI_PREALLOC : 0);
      startoffset_fsb   = XFS_B_TO_FSBT(mp, offset);
      allocatesize_fsb = XFS_B_TO_FSB(mp, count);

      /*    Generate a DMAPI event if needed.   */
      if (alloc_type != 0 && offset < ip->i_size &&
                  (attr_flags & XFS_ATTR_DMI) == 0  &&
                  DM_EVENT_ENABLED(ip, DM_EVENT_WRITE)) {
            xfs_off_t           end_dmi_offset;

            end_dmi_offset = offset+len;
            if (end_dmi_offset > ip->i_size)
                  end_dmi_offset = ip->i_size;
            error = XFS_SEND_DATA(mp, DM_EVENT_WRITE, ip, offset,
                              end_dmi_offset - offset, 0, NULL);
            if (error)
                  return error;
      }

      /*
       * Allocate file space until done or until there is an error
       */
retry:
      while (allocatesize_fsb && !error) {
            xfs_fileoff_t     s, e;

            /*
             * Determine space reservations for data/realtime.
             */
            if (unlikely(extsz)) {
                  s = startoffset_fsb;
                  do_div(s, extsz);
                  s *= extsz;
                  e = startoffset_fsb + allocatesize_fsb;
                  if ((temp = do_mod(startoffset_fsb, extsz)))
                        e += temp;
                  if ((temp = do_mod(e, extsz)))
                        e += extsz - temp;
            } else {
                  s = 0;
                  e = allocatesize_fsb;
            }

            if (unlikely(rt)) {
                  resrtextents = qblocks = (uint)(e - s);
                  resrtextents /= mp->m_sb.sb_rextsize;
                  resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
                  quota_flag = XFS_QMOPT_RES_RTBLKS;
            } else {
                  resrtextents = 0;
                  resblks = qblocks = \
                        XFS_DIOSTRAT_SPACE_RES(mp, (uint)(e - s));
                  quota_flag = XFS_QMOPT_RES_REGBLKS;
            }

            /*
             * Allocate and setup the transaction.
             */
            tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
            error = xfs_trans_reserve(tp, resblks,
                                XFS_WRITE_LOG_RES(mp), resrtextents,
                                XFS_TRANS_PERM_LOG_RES,
                                XFS_WRITE_LOG_COUNT);
            /*
             * Check for running out of space
             */
            if (error) {
                  /*
                   * Free the transaction structure.
                   */
                  ASSERT(error == ENOSPC || XFS_FORCED_SHUTDOWN(mp));
                  xfs_trans_cancel(tp, 0);
                  break;
            }
            xfs_ilock(ip, XFS_ILOCK_EXCL);
            error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks,
                                          0, quota_flag);
            if (error)
                  goto error1;

            xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
            xfs_trans_ihold(tp, ip);

            /*
             * Issue the xfs_bmapi() call to allocate the blocks
             */
            xfs_bmap_init(&free_list, &firstfsb);
            error = xfs_bmapi(tp, ip, startoffset_fsb,
                          allocatesize_fsb, bmapi_flag,
                          &firstfsb, 0, imapp, &nimaps,
                          &free_list, NULL);
            if (error) {
                  goto error0;
            }

            /*
             * Complete the transaction
             */
            error = xfs_bmap_finish(&tp, &free_list, &committed);
            if (error) {
                  goto error0;
            }

            error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
            xfs_iunlock(ip, XFS_ILOCK_EXCL);
            if (error) {
                  break;
            }

            allocated_fsb = imapp->br_blockcount;

            if (nimaps == 0) {
                  error = XFS_ERROR(ENOSPC);
                  break;
            }

            startoffset_fsb += allocated_fsb;
            allocatesize_fsb -= allocated_fsb;
      }
dmapi_enospc_check:
      if (error == ENOSPC && (attr_flags & XFS_ATTR_DMI) == 0 &&
          DM_EVENT_ENABLED(ip, DM_EVENT_NOSPACE)) {
            error = XFS_SEND_NAMESP(mp, DM_EVENT_NOSPACE,
                        ip, DM_RIGHT_NULL,
                        ip, DM_RIGHT_NULL,
                        NULL, NULL, 0, 0, 0); /* Delay flag intentionally unused */
            if (error == 0)
                  goto retry; /* Maybe DMAPI app. has made space */
            /* else fall through with error from XFS_SEND_DATA */
      }

      return error;

error0:     /* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
      xfs_bmap_cancel(&free_list);
      xfs_trans_unreserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);

error1:     /* Just cancel transaction */
      xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
      xfs_iunlock(ip, XFS_ILOCK_EXCL);
      goto dmapi_enospc_check;
}

/*
 * Zero file bytes between startoff and endoff inclusive.
 * The iolock is held exclusive and no blocks are buffered.
 *
 * This function is used by xfs_free_file_space() to zero
 * partial blocks when the range to free is not block aligned.
 * When unreserving space with boundaries that are not block
 * aligned we round up the start and round down the end
 * boundaries and then use this function to zero the parts of
 * the blocks that got dropped during the rounding.
 */
STATIC int
xfs_zero_remaining_bytes(
      xfs_inode_t       *ip,
      xfs_off_t         startoff,
      xfs_off_t         endoff)
{
      xfs_bmbt_irec_t         imap;
      xfs_fileoff_t           offset_fsb;
      xfs_off_t         lastoffset;
      xfs_off_t         offset;
      xfs_buf_t         *bp;
      xfs_mount_t       *mp = ip->i_mount;
      int               nimap;
      int               error = 0;

      /*
       * Avoid doing I/O beyond eof - it's not necessary
       * since nothing can read beyond eof.  The space will
       * be zeroed when the file is extended anyway.
       */
      if (startoff >= ip->i_size)
            return 0;

      if (endoff > ip->i_size)
            endoff = ip->i_size;

      bp = xfs_buf_get_noaddr(mp->m_sb.sb_blocksize,
                        XFS_IS_REALTIME_INODE(ip) ?
                        mp->m_rtdev_targp : mp->m_ddev_targp);
      if (!bp)
            return XFS_ERROR(ENOMEM);

      for (offset = startoff; offset <= endoff; offset = lastoffset + 1) {
            offset_fsb = XFS_B_TO_FSBT(mp, offset);
            nimap = 1;
            error = xfs_bmapi(NULL, ip, offset_fsb, 1, 0,
                  NULL, 0, &imap, &nimap, NULL, NULL);
            if (error || nimap < 1)
                  break;
            ASSERT(imap.br_blockcount >= 1);
            ASSERT(imap.br_startoff == offset_fsb);
            lastoffset = XFS_FSB_TO_B(mp, imap.br_startoff + 1) - 1;
            if (lastoffset > endoff)
                  lastoffset = endoff;
            if (imap.br_startblock == HOLESTARTBLOCK)
                  continue;
            ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
            if (imap.br_state == XFS_EXT_UNWRITTEN)
                  continue;
            XFS_BUF_UNDONE(bp);
            XFS_BUF_UNWRITE(bp);
            XFS_BUF_READ(bp);
            XFS_BUF_SET_ADDR(bp, xfs_fsb_to_db(ip, imap.br_startblock));
            xfsbdstrat(mp, bp);
            error = xfs_iowait(bp);
            if (error) {
                  xfs_ioerror_alert("xfs_zero_remaining_bytes(read)",
                                mp, bp, XFS_BUF_ADDR(bp));
                  break;
            }
            memset(XFS_BUF_PTR(bp) +
                  (offset - XFS_FSB_TO_B(mp, imap.br_startoff)),
                  0, lastoffset - offset + 1);
            XFS_BUF_UNDONE(bp);
            XFS_BUF_UNREAD(bp);
            XFS_BUF_WRITE(bp);
            xfsbdstrat(mp, bp);
            error = xfs_iowait(bp);
            if (error) {
                  xfs_ioerror_alert("xfs_zero_remaining_bytes(write)",
                                mp, bp, XFS_BUF_ADDR(bp));
                  break;
            }
      }
      xfs_buf_free(bp);
      return error;
}

/*
 * xfs_free_file_space()
 *      This routine frees disk space for the given file.
 *
 *    This routine is only called by xfs_change_file_space
 *    for an UNRESVSP type call.
 *
 * RETURNS:
 *       0 on success
 *      errno on error
 *
 */
STATIC int
xfs_free_file_space(
      xfs_inode_t       *ip,
      xfs_off_t         offset,
      xfs_off_t         len,
      int               attr_flags)
{
      int               committed;
      int               done;
      xfs_off_t         end_dmi_offset;
      xfs_fileoff_t           endoffset_fsb;
      int               error;
      xfs_fsblock_t           firstfsb;
      xfs_bmap_free_t         free_list;
      xfs_bmbt_irec_t         imap;
      xfs_off_t         ioffset;
      xfs_extlen_t            mod=0;
      xfs_mount_t       *mp;
      int               nimap;
      uint              resblks;
      uint              rounding;
      int               rt;
      xfs_fileoff_t           startoffset_fsb;
      xfs_trans_t       *tp;
      int               need_iolock = 1;

      mp = ip->i_mount;

      xfs_itrace_entry(ip);

      error = xfs_qm_dqattach(ip, 0);
      if (error)
            return error;

      error = 0;
      if (len <= 0)     /* if nothing being freed */
            return error;
      rt = XFS_IS_REALTIME_INODE(ip);
      startoffset_fsb   = XFS_B_TO_FSB(mp, offset);
      end_dmi_offset = offset + len;
      endoffset_fsb = XFS_B_TO_FSBT(mp, end_dmi_offset);

      if (offset < ip->i_size && (attr_flags & XFS_ATTR_DMI) == 0 &&
          DM_EVENT_ENABLED(ip, DM_EVENT_WRITE)) {
            if (end_dmi_offset > ip->i_size)
                  end_dmi_offset = ip->i_size;
            error = XFS_SEND_DATA(mp, DM_EVENT_WRITE, ip,
                        offset, end_dmi_offset - offset,
                        AT_DELAY_FLAG(attr_flags), NULL);
            if (error)
                  return error;
      }

      if (attr_flags & XFS_ATTR_NOLOCK)
            need_iolock = 0;
      if (need_iolock) {
            xfs_ilock(ip, XFS_IOLOCK_EXCL);
            /* wait for the completion of any pending DIOs */
            xfs_ioend_wait(ip);
      }

      rounding = max_t(uint, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
      ioffset = offset & ~(rounding - 1);

      if (VN_CACHED(VFS_I(ip)) != 0) {
            xfs_inval_cached_trace(ip, ioffset, -1, ioffset, -1);
            error = xfs_flushinval_pages(ip, ioffset, -1, FI_REMAPF_LOCKED);
            if (error)
                  goto out_unlock_iolock;
      }

      /*
       * Need to zero the stuff we're not freeing, on disk.
       * If it's a realtime file & can't use unwritten extents then we
       * actually need to zero the extent edges.  Otherwise xfs_bunmapi
       * will take care of it for us.
       */
      if (rt && !xfs_sb_version_hasextflgbit(&mp->m_sb)) {
            nimap = 1;
            error = xfs_bmapi(NULL, ip, startoffset_fsb,
                  1, 0, NULL, 0, &imap, &nimap, NULL, NULL);
            if (error)
                  goto out_unlock_iolock;
            ASSERT(nimap == 0 || nimap == 1);
            if (nimap && imap.br_startblock != HOLESTARTBLOCK) {
                  xfs_daddr_t block;

                  ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
                  block = imap.br_startblock;
                  mod = do_div(block, mp->m_sb.sb_rextsize);
                  if (mod)
                        startoffset_fsb += mp->m_sb.sb_rextsize - mod;
            }
            nimap = 1;
            error = xfs_bmapi(NULL, ip, endoffset_fsb - 1,
                  1, 0, NULL, 0, &imap, &nimap, NULL, NULL);
            if (error)
                  goto out_unlock_iolock;
            ASSERT(nimap == 0 || nimap == 1);
            if (nimap && imap.br_startblock != HOLESTARTBLOCK) {
                  ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
                  mod++;
                  if (mod && (mod != mp->m_sb.sb_rextsize))
                        endoffset_fsb -= mod;
            }
      }
      if ((done = (endoffset_fsb <= startoffset_fsb)))
            /*
             * One contiguous piece to clear
             */
            error = xfs_zero_remaining_bytes(ip, offset, offset + len - 1);
      else {
            /*
             * Some full blocks, possibly two pieces to clear
             */
            if (offset < XFS_FSB_TO_B(mp, startoffset_fsb))
                  error = xfs_zero_remaining_bytes(ip, offset,
                        XFS_FSB_TO_B(mp, startoffset_fsb) - 1);
            if (!error &&
                XFS_FSB_TO_B(mp, endoffset_fsb) < offset + len)
                  error = xfs_zero_remaining_bytes(ip,
                        XFS_FSB_TO_B(mp, endoffset_fsb),
                        offset + len - 1);
      }

      /*
       * free file space until done or until there is an error
       */
      resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
      while (!error && !done) {

            /*
             * allocate and setup the transaction. Allow this
             * transaction to dip into the reserve blocks to ensure
             * the freeing of the space succeeds at ENOSPC.
             */
            tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
            tp->t_flags |= XFS_TRANS_RESERVE;
            error = xfs_trans_reserve(tp,
                                resblks,
                                XFS_WRITE_LOG_RES(mp),
                                0,
                                XFS_TRANS_PERM_LOG_RES,
                                XFS_WRITE_LOG_COUNT);

            /*
             * check for running out of space
             */
            if (error) {
                  /*
                   * Free the transaction structure.
                   */
                  ASSERT(error == ENOSPC || XFS_FORCED_SHUTDOWN(mp));
                  xfs_trans_cancel(tp, 0);
                  break;
            }
            xfs_ilock(ip, XFS_ILOCK_EXCL);
            error = xfs_trans_reserve_quota(tp, mp,
                        ip->i_udquot, ip->i_gdquot,
                        resblks, 0, XFS_QMOPT_RES_REGBLKS);
            if (error)
                  goto error1;

            xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
            xfs_trans_ihold(tp, ip);

            /*
             * issue the bunmapi() call to free the blocks
             */
            xfs_bmap_init(&free_list, &firstfsb);
            error = xfs_bunmapi(tp, ip, startoffset_fsb,
                          endoffset_fsb - startoffset_fsb,
                          0, 2, &firstfsb, &free_list, NULL, &done);
            if (error) {
                  goto error0;
            }

            /*
             * complete the transaction
             */
            error = xfs_bmap_finish(&tp, &free_list, &committed);
            if (error) {
                  goto error0;
            }

            error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
            xfs_iunlock(ip, XFS_ILOCK_EXCL);
      }

 out_unlock_iolock:
      if (need_iolock)
            xfs_iunlock(ip, XFS_IOLOCK_EXCL);
      return error;

 error0:
      xfs_bmap_cancel(&free_list);
 error1:
      xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
      xfs_iunlock(ip, need_iolock ? (XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL) :
                XFS_ILOCK_EXCL);
      return error;
}

/*
 * xfs_change_file_space()
 *      This routine allocates or frees disk space for the given file.
 *      The user specified parameters are checked for alignment and size
 *      limitations.
 *
 * RETURNS:
 *       0 on success
 *      errno on error
 *
 */
int
xfs_change_file_space(
      xfs_inode_t *ip,
      int         cmd,
      xfs_flock64_t     *bf,
      xfs_off_t   offset,
      int         attr_flags)
{
      xfs_mount_t *mp = ip->i_mount;
      int         clrprealloc;
      int         error;
      xfs_fsize_t fsize;
      int         setprealloc;
      xfs_off_t   startoffset;
      xfs_off_t   llen;
      xfs_trans_t *tp;
      struct iattr      iattr;

      xfs_itrace_entry(ip);

      if (!S_ISREG(ip->i_d.di_mode))
            return XFS_ERROR(EINVAL);

      switch (bf->l_whence) {
      case 0: /*SEEK_SET*/
            break;
      case 1: /*SEEK_CUR*/
            bf->l_start += offset;
            break;
      case 2: /*SEEK_END*/
            bf->l_start += ip->i_size;
            break;
      default:
            return XFS_ERROR(EINVAL);
      }

      llen = bf->l_len > 0 ? bf->l_len - 1 : bf->l_len;

      if (   (bf->l_start < 0)
          || (bf->l_start > XFS_MAXIOFFSET(mp))
          || (bf->l_start + llen < 0)
          || (bf->l_start + llen > XFS_MAXIOFFSET(mp)))
            return XFS_ERROR(EINVAL);

      bf->l_whence = 0;

      startoffset = bf->l_start;
      fsize = ip->i_size;

      /*
       * XFS_IOC_RESVSP and XFS_IOC_UNRESVSP will reserve or unreserve
       * file space.
       * These calls do NOT zero the data space allocated to the file,
       * nor do they change the file size.
       *
       * XFS_IOC_ALLOCSP and XFS_IOC_FREESP will allocate and free file
       * space.
       * These calls cause the new file data to be zeroed and the file
       * size to be changed.
       */
      setprealloc = clrprealloc = 0;

      switch (cmd) {
      case XFS_IOC_RESVSP:
      case XFS_IOC_RESVSP64:
            error = xfs_alloc_file_space(ip, startoffset, bf->l_len,
                                                1, attr_flags);
            if (error)
                  return error;
            setprealloc = 1;
            break;

      case XFS_IOC_UNRESVSP:
      case XFS_IOC_UNRESVSP64:
            if ((error = xfs_free_file_space(ip, startoffset, bf->l_len,
                                                attr_flags)))
                  return error;
            break;

      case XFS_IOC_ALLOCSP:
      case XFS_IOC_ALLOCSP64:
      case XFS_IOC_FREESP:
      case XFS_IOC_FREESP64:
            if (startoffset > fsize) {
                  error = xfs_alloc_file_space(ip, fsize,
                              startoffset - fsize, 0, attr_flags);
                  if (error)
                        break;
            }

            iattr.ia_valid = ATTR_SIZE;
            iattr.ia_size = startoffset;

            error = xfs_setattr(ip, &iattr, attr_flags);

            if (error)
                  return error;

            clrprealloc = 1;
            break;

      default:
            ASSERT(0);
            return XFS_ERROR(EINVAL);
      }

      /*
       * update the inode timestamp, mode, and prealloc flag bits
       */
      tp = xfs_trans_alloc(mp, XFS_TRANS_WRITEID);

      if ((error = xfs_trans_reserve(tp, 0, XFS_WRITEID_LOG_RES(mp),
                              0, 0, 0))) {
            /* ASSERT(0); */
            xfs_trans_cancel(tp, 0);
            return error;
      }

      xfs_ilock(ip, XFS_ILOCK_EXCL);

      xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
      xfs_trans_ihold(tp, ip);

      if ((attr_flags & XFS_ATTR_DMI) == 0) {
            ip->i_d.di_mode &= ~S_ISUID;

            /*
             * Note that we don't have to worry about mandatory
             * file locking being disabled here because we only
             * clear the S_ISGID bit if the Group execute bit is
             * on, but if it was on then mandatory locking wouldn't
             * have been enabled.
             */
            if (ip->i_d.di_mode & S_IXGRP)
                  ip->i_d.di_mode &= ~S_ISGID;

            xfs_ichgtime(ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
      }
      if (setprealloc)
            ip->i_d.di_flags |= XFS_DIFLAG_PREALLOC;
      else if (clrprealloc)
            ip->i_d.di_flags &= ~XFS_DIFLAG_PREALLOC;

      xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
      xfs_trans_set_sync(tp);

      error = xfs_trans_commit(tp, 0);

      xfs_iunlock(ip, XFS_ILOCK_EXCL);

      return error;
}

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