xfs_utils.c

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/*
 * Copyright (c) 2000-2002,2005 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_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_itable.h"
#include "xfs_utils.h"


/*
 * Allocates a new inode from disk and return a pointer to the
 * incore copy. This routine will internally commit the current
 * transaction and allocate a new one if the Space Manager needed
 * to do an allocation to replenish the inode free-list.
 *
 * This routine is designed to be called from xfs_create and
 * xfs_create_dir.
 *
 */
int
xfs_dir_ialloc(
    xfs_trans_t **tpp,      /* input: current transaction;
                       output: may be a new transaction. */
    xfs_inode_t *dp,        /* directory within whose allocate
                       the inode. */
    umode_t     mode,
    xfs_nlink_t nlink,
    xfs_dev_t   rdev,
    prid_t      prid,       /* project id */
    int     okalloc,    /* ok to allocate new space */
    xfs_inode_t **ipp,      /* pointer to inode; it will be
                       locked. */
    int     *committed)

{
    xfs_trans_t *tp;
    xfs_trans_t *ntp;
    xfs_inode_t *ip;
    xfs_buf_t   *ialloc_context = NULL;
    int     code;
    uint        log_res;
    uint        log_count;
    void        *dqinfo;
    uint        tflags;

    tp = *tpp;
    ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);

    /*
     * xfs_ialloc will return a pointer to an incore inode if
     * the Space Manager has an available inode on the free
     * list. Otherwise, it will do an allocation and replenish
     * the freelist.  Since we can only do one allocation per
     * transaction without deadlocks, we will need to commit the
     * current transaction and start a new one.  We will then
     * need to call xfs_ialloc again to get the inode.
     *
     * If xfs_ialloc did an allocation to replenish the freelist,
     * it returns the bp containing the head of the freelist as
     * ialloc_context. We will hold a lock on it across the
     * transaction commit so that no other process can steal
     * the inode(s) that we've just allocated.
     */
    code = xfs_ialloc(tp, dp, mode, nlink, rdev, prid, okalloc,
              &ialloc_context, &ip);

    /*
     * Return an error if we were unable to allocate a new inode.
     * This should only happen if we run out of space on disk or
     * encounter a disk error.
     */
    if (code) {
        *ipp = NULL;
        return code;
    }
    if (!ialloc_context && !ip) {
        *ipp = NULL;
        return XFS_ERROR(ENOSPC);
    }

    /*
     * If the AGI buffer is non-NULL, then we were unable to get an
     * inode in one operation.  We need to commit the current
     * transaction and call xfs_ialloc() again.  It is guaranteed
     * to succeed the second time.
     */
    if (ialloc_context) {
        /*
         * Normally, xfs_trans_commit releases all the locks.
         * We call bhold to hang on to the ialloc_context across
         * the commit.  Holding this buffer prevents any other
         * processes from doing any allocations in this
         * allocation group.
         */
        xfs_trans_bhold(tp, ialloc_context);
        /*
         * Save the log reservation so we can use
         * them in the next transaction.
         */
        log_res = xfs_trans_get_log_res(tp);
        log_count = xfs_trans_get_log_count(tp);

        /*
         * We want the quota changes to be associated with the next
         * transaction, NOT this one. So, detach the dqinfo from this
         * and attach it to the next transaction.
         */
        dqinfo = NULL;
        tflags = 0;
        if (tp->t_dqinfo) {
            dqinfo = (void *)tp->t_dqinfo;
            tp->t_dqinfo = NULL;
            tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
            tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
        }

        ntp = xfs_trans_dup(tp);
        code = xfs_trans_commit(tp, 0);
        tp = ntp;
        if (committed != NULL) {
            *committed = 1;
        }
        /*
         * If we get an error during the commit processing,
         * release the buffer that is still held and return
         * to the caller.
         */
        if (code) {
            xfs_buf_relse(ialloc_context);
            if (dqinfo) {
                tp->t_dqinfo = dqinfo;
                xfs_trans_free_dqinfo(tp);
            }
            *tpp = ntp;
            *ipp = NULL;
            return code;
        }

        /*
         * 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);
        code = xfs_trans_reserve(tp, 0, log_res, 0,
                     XFS_TRANS_PERM_LOG_RES, log_count);
        /*
         * Re-attach the quota info that we detached from prev trx.
         */
        if (dqinfo) {
            tp->t_dqinfo = dqinfo;
            tp->t_flags |= tflags;
        }

        if (code) {
            xfs_buf_relse(ialloc_context);
            *tpp = ntp;
            *ipp = NULL;
            return code;
        }
        xfs_trans_bjoin(tp, ialloc_context);

        /*
         * Call ialloc again. Since we've locked out all
         * other allocations in this allocation group,
         * this call should always succeed.
         */
        code = xfs_ialloc(tp, dp, mode, nlink, rdev, prid,
                  okalloc, &ialloc_context, &ip);

        /*
         * If we get an error at this point, return to the caller
         * so that the current transaction can be aborted.
         */
        if (code) {
            *tpp = tp;
            *ipp = NULL;
            return code;
        }
        ASSERT(!ialloc_context && ip);

    } else {
        if (committed != NULL)
            *committed = 0;
    }

    *ipp = ip;
    *tpp = tp;

    return 0;
}

/*
 * Decrement the link count on an inode & log the change.
 * If this causes the link count to go to zero, initiate the
 * logging activity required to truncate a file.
 */
int             /* error */
xfs_droplink(
    xfs_trans_t *tp,
    xfs_inode_t *ip)
{
    int error;

    xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);

    ASSERT (ip->i_d.di_nlink > 0);
    ip->i_d.di_nlink--;
    drop_nlink(VFS_I(ip));
    xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

    error = 0;
    if (ip->i_d.di_nlink == 0) {
        /*
         * We're dropping the last link to this file.
         * Move the on-disk inode to the AGI unlinked list.
         * From xfs_inactive() we will pull the inode from
         * the list and free it.
         */
        error = xfs_iunlink(tp, ip);
    }
    return error;
}

/*
 * This gets called when the inode's version needs to be changed from 1 to 2.
 * Currently this happens when the nlink field overflows the old 16-bit value
 * or when chproj is called to change the project for the first time.
 * As a side effect the superblock version will also get rev'd
 * to contain the NLINK bit.
 */
void
xfs_bump_ino_vers2(
    xfs_trans_t *tp,
    xfs_inode_t *ip)
{
    xfs_mount_t *mp;

    ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
    ASSERT(ip->i_d.di_version == 1);

    ip->i_d.di_version = 2;
    ip->i_d.di_onlink = 0;
    memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
    mp = tp->t_mountp;
    if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
        spin_lock(&mp->m_sb_lock);
        if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
            xfs_sb_version_addnlink(&mp->m_sb);
            spin_unlock(&mp->m_sb_lock);
            xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
        } else {
            spin_unlock(&mp->m_sb_lock);
        }
    }
    /* Caller must log the inode */
}

/*
 * Increment the link count on an inode & log the change.
 */
int
xfs_bumplink(
    xfs_trans_t *tp,
    xfs_inode_t *ip)
{
    xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);

    ASSERT(ip->i_d.di_nlink > 0);
    ip->i_d.di_nlink++;
    inc_nlink(VFS_I(ip));
    if ((ip->i_d.di_version == 1) &&
        (ip->i_d.di_nlink > XFS_MAXLINK_1)) {
        /*
         * The inode has increased its number of links beyond
         * what can fit in an old format inode.  It now needs
         * to be converted to a version 2 inode with a 32 bit
         * link count.  If this is the first inode in the file
         * system to do this, then we need to bump the superblock
         * version number as well.
         */
        xfs_bump_ino_vers2(tp, ip);
    }

    xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
    return 0;
}