xfs_vnodeops.c

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/*
 * 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_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_itable.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_acl.h"
#include "xfs_attr.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"
#include "xfs_trace.h"

/*
 * 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_read(ip, 0, XFS_B_TO_FSB(mp, pathlen), mval, &nmaps,
                   0);
    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(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0);
        if (!bp)
            return XFS_ERROR(ENOMEM);
        error = bp->b_error;
        if (error) {
            xfs_buf_ioerror_alert(bp, __func__);
            xfs_buf_relse(bp);
            goto out;
        }
        if (pathlen < byte_cnt)
            byte_cnt = pathlen;
        pathlen -= byte_cnt;

        memcpy(link, bp->b_addr, 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;
    xfs_fsize_t pathlen;
    int     error = 0;

    trace_xfs_readlink(ip);

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

    xfs_ilock(ip, XFS_ILOCK_SHARED);

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

    if (pathlen < 0 || pathlen > MAXPATHLEN) {
        xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
             __func__, (unsigned long long) ip->i_ino,
             (long long) pathlen);
        ASSERT(0);
        error = XFS_ERROR(EFSCORRUPTED);
        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;
}

/*
 * 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.
 */
STATIC int
xfs_free_eofblocks(
    xfs_mount_t *mp,
    xfs_inode_t *ip,
    bool        need_iolock)
{
    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;

    /*
     * 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)XFS_ISIZE(ip));
    last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
    if (last_fsb <= end_fsb)
        return 0;
    map_len = last_fsb - end_fsb;

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

        if (need_iolock) {
            if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
                xfs_trans_cancel(tp, 0);
                return 0;
            }
        }

        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);
            if (need_iolock)
                xfs_iunlock(ip, XFS_IOLOCK_EXCL);
            return error;
        }

        xfs_ilock(ip, XFS_ILOCK_EXCL);
        xfs_trans_ijoin(tp, ip, 0);

        /*
         * Do not update the on-disk file size.  If we update the
         * on-disk file size and then the system crashes before the
         * contents of the file are flushed to disk then the files
         * may be full of holes (ie NULL files bug).
         */
        error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK,
                          XFS_ISIZE(ip));
        if (error) {
            /*
             * If we get an error at this point we simply don't
             * bother truncating the file.
             */
            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, XFS_ILOCK_EXCL);
        if (need_iolock)
            xfs_iunlock(ip, XFS_IOLOCK_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);

    /*
     * 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.
     */
    size = (int)ip->i_d.di_size;
    ip->i_d.di_size = 0;
    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);
    error = xfs_bmapi_read(ip, 0, XFS_B_TO_FSB(mp, size),
                mval, &nmaps, 0);
    if (error)
        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);
        if (!bp) {
            error = ENOMEM;
            goto error1;
        }
        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, &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, 0);
    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;
    }

    xfs_trans_ijoin(tp, ip, 0);
    *tpp = tp;
    return 0;

 error1:
    xfs_bmap_cancel(&free_list);
 error0:
    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 noticeable 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) {
            xfs_iflags_clear(ip, XFS_IDIRTY_RELEASE);
            if (VN_DIRTY(VFS_I(ip)) && ip->i_delayed_blks > 0)
                xfs_flush_pages(ip, 0, -1, XBF_ASYNC, FI_NONE);
        }
    }

    if (ip->i_d.di_nlink == 0)
        return 0;

    if ((S_ISREG(ip->i_d.di_mode) &&
         (VFS_I(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)))) {

        /*
         * If we can't get the iolock just skip truncating the blocks
         * past EOF because we could deadlock with the mmap_sem
         * otherwise.  We'll get another chance to drop them once the
         * last reference to the inode is dropped, so we'll never leak
         * blocks permanently.
         *
         * Further, check if the inode is being opened, written and
         * closed frequently and we have delayed allocation blocks
         * outstanding (e.g. streaming writes from the NFS server),
         * truncating the blocks past EOF will cause fragmentation to
         * occur.
         *
         * In this case don't do the truncation, either, but we have to
         * be careful how we detect this case. Blocks beyond EOF show
         * up as i_delayed_blks even when the inode is clean, so we
         * need to truncate them away first before checking for a dirty
         * release. Hence on the first dirty close we will still remove
         * the speculative allocation, but after that we will leave it
         * in place.
         */
        if (xfs_iflags_test(ip, XFS_IDIRTY_RELEASE))
            return 0;

        error = xfs_free_eofblocks(mp, ip, true);
        if (error)
            return error;

        /* delalloc blocks after truncation means it really is dirty */
        if (ip->i_delayed_blks)
            xfs_iflags_set(ip, XFS_IDIRTY_RELEASE);
    }
    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 = 0;

    /*
     * 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;
    }

    mp = ip->i_mount;

    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 ((S_ISREG(ip->i_d.di_mode) &&
            (VFS_I(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, false);
            if (error)
                return VN_INACTIVE_CACHE;
        }
        goto out;
    }

    if (S_ISREG(ip->i_d.di_mode) &&
        (ip->i_d.di_size != 0 || XFS_ISIZE(ip) != 0 ||
         ip->i_d.di_nextents > 0 || ip->i_delayed_blks > 0))
        truncate = 1;

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

    tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
    error = xfs_trans_reserve(tp, 0,
            (truncate || S_ISLNK(ip->i_d.di_mode)) ?
                XFS_ITRUNCATE_LOG_RES(mp) :
                XFS_IFREE_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);
        return VN_INACTIVE_CACHE;
    }

    xfs_ilock(ip, XFS_ILOCK_EXCL);
    xfs_trans_ijoin(tp, ip, 0);

    if (S_ISLNK(ip->i_d.di_mode)) {
        /*
         * Zero length symlinks _can_ exist.
         */
        if (ip->i_d.di_size > XFS_IFORK_DSIZE(ip)) {
            error = xfs_inactive_symlink_rmt(ip, &tp);
            if (error)
                goto out_cancel;
        } else 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);
        }
    } else if (truncate) {
        ip->i_d.di_size = 0;
        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

        error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, 0);
        if (error)
            goto out_cancel;

        ASSERT(ip->i_d.di_nextents == 0);
    }

    /*
     * 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) {
        ASSERT(ip->i_d.di_forkoff != 0);

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

        xfs_iunlock(ip, XFS_ILOCK_EXCL);

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

        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) {
            xfs_trans_cancel(tp, 0);
            goto out;
        }

        xfs_ilock(ip, XFS_ILOCK_EXCL);
        xfs_trans_ijoin(tp, ip, 0);
    }

    if (ip->i_afp)
        xfs_idestroy_fork(ip, XFS_ATTR_FORK);

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

    /*
     * 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)) {
            xfs_notice(mp, "%s: xfs_ifree returned error %d",
                __func__, error);
            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_notice(mp, "%s: xfs_bmap_finish returned error %d",
                __func__, error);
        error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
        if (error)
            xfs_notice(mp, "%s: xfs_trans_commit returned error %d",
                __func__, error);
    }

    /*
     * Release the dquots held by inode, if any.
     */
    xfs_qm_dqdetach(ip);
out_unlock:
    xfs_iunlock(ip, XFS_ILOCK_EXCL);
out:
    return VN_INACTIVE_CACHE;
out_cancel:
    xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
    goto out_unlock;
}

/*
 * 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;

    trace_xfs_lookup(dp, name);

    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);
    if (error)
        goto out_free_name;

    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,
    umode_t         mode,
    xfs_dev_t       rdev,
    xfs_inode_t     **ipp)
{
    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;
    prid_t          prid;
    struct xfs_dquot    *udqp = NULL;
    struct xfs_dquot    *gdqp = NULL;
    uint            resblks;
    uint            log_res;
    uint            log_count;

    trace_xfs_create(dp, name);

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

    if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
        prid = xfs_get_projid(dp);
    else
        prid = XFS_PROJID_DEFAULT;

    /*
     * 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)
        return error;

    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, log_res, 0,
                XFS_TRANS_PERM_LOG_RES, 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;

    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,
                   prid, resblks > 0, &ip, &committed);
    if (error) {
        if (error == ENOSPC)
            goto out_trans_cancel;
        goto out_trans_abort;
    }

    /*
     * 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.
     */
    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_trans_ichgtime(tp, 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);

    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 out_release_inode;

    xfs_qm_dqrele(udqp);
    xfs_qm_dqrele(gdqp);

    *ipp = ip;
    return 0;

 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_release_inode:
    /*
     * Wait until after the current transaction is aborted to
     * release the inode.  This prevents recursive transactions
     * and deadlocks from xfs_inactive.
     */
    if (ip)
        IRELE(ip);

    xfs_qm_dqrele(udqp);
    xfs_qm_dqrele(gdqp);

    if (unlock_dp_on_error)
        xfs_iunlock(dp, XFS_ILOCK_EXCL);
    return error;
}

#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;

    trace_xfs_remove(dp, name);

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

    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);

    xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
    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_trans_ichgtime(tp, 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);

    return 0;

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

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;

    trace_xfs_link(tdp, target_name);

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

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

    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);

    xfs_trans_ijoin(tp, sip, XFS_ILOCK_EXCL);
    xfs_trans_ijoin(tp, tdp, XFS_ILOCK_EXCL);

    /*
     * 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) &&
             (xfs_get_projid(tdp) != xfs_get_projid(sip)))) {
        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_trans_ichgtime(tp, 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;
    }

    return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);

 abort_return:
    cancel_flags |= XFS_TRANS_ABORT;
 error_return:
    xfs_trans_cancel(tp, cancel_flags);
 std_return:
    return error;
}

int
xfs_symlink(
    xfs_inode_t     *dp,
    struct xfs_name     *link_name,
    const char      *target_path,
    umode_t         mode,
    xfs_inode_t     **ipp)
{
    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;
    prid_t          prid;
    struct xfs_dquot    *udqp, *gdqp;
    uint            resblks;

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

    trace_xfs_symlink(dp, link_name);

    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);

    udqp = gdqp = NULL;
    if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
        prid = xfs_get_projid(dp);
    else
        prid = XFS_PROJID_DEFAULT;

    /*
     * 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,
                   prid, resblks > 0, &ip, NULL);
    if (error) {
        if (error == ENOSPC)
            goto error_return;
        goto error1;
    }

    /*
     * 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.
     */
    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_write(tp, ip, first_fsb, fs_blocks,
                  XFS_BMAPI_METADATA, &first_block, resblks,
                  mval, &nmaps, &free_list);
        if (error)
            goto error2;

        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);
            if (!bp) {
                error = ENOMEM;
                goto error2;
            }
            if (pathlen < byte_cnt) {
                byte_cnt = pathlen;
            }
            pathlen -= byte_cnt;

            memcpy(bp->b_addr, 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 error2;
    xfs_trans_ichgtime(tp, 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);
    }

    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);

    *ipp = ip;
    return 0;

 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);
 std_return:
    return error;
}

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);
    error = xfs_trans_commit(tp, 0);

    return error;
}

/*
 * 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         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;

    trace_xfs_alloc_file_space(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;
    startoffset_fsb = XFS_B_TO_FSBT(mp, offset);
    allocatesize_fsb = XFS_B_TO_FSB(mp, count);

    /*
     * Allocate file space until done or until there is an error
     */
    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;
        }

        /*
         * The transaction reservation is limited to a 32-bit block
         * count, hence we need to limit the number of blocks we are
         * trying to reserve to avoid an overflow. We can't allocate
         * more than @nimaps extents, and an extent is limited on disk
         * to MAXEXTLEN (21 bits), so use that to enforce the limit.
         */
        resblks = min_t(xfs_fileoff_t, (e - s), (MAXEXTLEN * nimaps));
        if (unlikely(rt)) {
            resrtextents = qblocks = resblks;
            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, resblks);
            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, 0);

        xfs_bmap_init(&free_list, &firstfsb);
        error = xfs_bmapi_write(tp, ip, startoffset_fsb,
                    allocatesize_fsb, alloc_type, &firstfsb,
                    0, imapp, &nimaps, &free_list);
        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;
    }

    return error;

error0: /* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
    xfs_bmap_cancel(&free_list);
    xfs_trans_unreserve_quota_nblks(tp, ip, (long)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);
    return error;
}

/*
 * 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 >= XFS_ISIZE(ip))
        return 0;

    if (endoff > XFS_ISIZE(ip))
        endoff = XFS_ISIZE(ip);

    bp = xfs_buf_get_uncached(XFS_IS_REALTIME_INODE(ip) ?
                    mp->m_rtdev_targp : mp->m_ddev_targp,
                  BTOBB(mp->m_sb.sb_blocksize), 0);
    if (!bp)
        return XFS_ERROR(ENOMEM);

    xfs_buf_unlock(bp);

    for (offset = startoff; offset <= endoff; offset = lastoffset + 1) {
        offset_fsb = XFS_B_TO_FSBT(mp, offset);
        nimap = 1;
        error = xfs_bmapi_read(ip, offset_fsb, 1, &imap, &nimap, 0);
        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_buf_iowait(bp);
        if (error) {
            xfs_buf_ioerror_alert(bp,
                    "xfs_zero_remaining_bytes(read)");
            break;
        }
        memset(bp->b_addr +
            (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_buf_iowait(bp);
        if (error) {
            xfs_buf_ioerror_alert(bp,
                    "xfs_zero_remaining_bytes(write)");
            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_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;

    trace_xfs_free_file_space(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);
    endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);

    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 */
        inode_dio_wait(VFS_I(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) {
        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_read(ip, startoffset_fsb, 1,
                    &imap, &nimap, 0);
        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_read(ip, endoffset_fsb - 1, 1,
                    &imap, &nimap, 0);
        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, 0);

        /*
         * 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, &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;
    int     prealloc_type;

    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 += XFS_ISIZE(ip);
        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 > mp->m_super->s_maxbytes ||
        bf->l_start + llen < 0 ||
        bf->l_start + llen > mp->m_super->s_maxbytes)
        return XFS_ERROR(EINVAL);

    bf->l_whence = 0;

    startoffset = bf->l_start;
    fsize = XFS_ISIZE(ip);

    /*
     * 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;
    prealloc_type = XFS_BMAPI_PREALLOC;

    switch (cmd) {
    case XFS_IOC_ZERO_RANGE:
        prealloc_type |= XFS_BMAPI_CONVERT;
        xfs_tosspages(ip, startoffset, startoffset + bf->l_len, 0);
        /* FALLTHRU */
    case XFS_IOC_RESVSP:
    case XFS_IOC_RESVSP64:
        error = xfs_alloc_file_space(ip, startoffset, bf->l_len,
                        prealloc_type, 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:
        /*
         * These operations actually do IO when extending the file, but
         * the allocation is done seperately to the zeroing that is
         * done. This set of operations need to be serialised against
         * other IO operations, such as truncate and buffered IO. We
         * need to take the IOLOCK here to serialise the allocation and
         * zeroing IO to prevent other IOLOCK holders (e.g. getbmap,
         * truncate, direct IO) from racing against the transient
         * allocated but not written state we can have here.
         */
        xfs_ilock(ip, XFS_IOLOCK_EXCL);
        if (startoffset > fsize) {
            error = xfs_alloc_file_space(ip, fsize,
                    startoffset - fsize, 0,
                    attr_flags | XFS_ATTR_NOLOCK);
            if (error) {
                xfs_iunlock(ip, XFS_IOLOCK_EXCL);
                break;
            }
        }

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

        error = xfs_setattr_size(ip, &iattr,
                     attr_flags | XFS_ATTR_NOLOCK);
        xfs_iunlock(ip, XFS_IOLOCK_EXCL);

        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);

    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_trans_ichgtime(tp, 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);
    if (attr_flags & XFS_ATTR_SYNC)
        xfs_trans_set_sync(tp);
    return xfs_trans_commit(tp, 0);
}