jfs_mount.c

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/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 *
 *   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; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will 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 to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 * Module: jfs_mount.c
 *
 * note: file system in transition to aggregate/fileset:
 *
 * file system mount is interpreted as the mount of aggregate,
 * if not already mounted, and mount of the single/only fileset in
 * the aggregate;
 *
 * a file system/aggregate is represented by an internal inode
 * (aka mount inode) initialized with aggregate superblock;
 * each vfs represents a fileset, and points to its "fileset inode
 * allocation map inode" (aka fileset inode):
 * (an aggregate itself is structured recursively as a filset:
 * an internal vfs is constructed and points to its "fileset inode
 * allocation map inode" (aka aggregate inode) where each inode
 * represents a fileset inode) so that inode number is mapped to
 * on-disk inode in uniform way at both aggregate and fileset level;
 *
 * each vnode/inode of a fileset is linked to its vfs (to facilitate
 * per fileset inode operations, e.g., unmount of a fileset, etc.);
 * each inode points to the mount inode (to facilitate access to
 * per aggregate information, e.g., block size, etc.) as well as
 * its file set inode.
 *
 *   aggregate
 *   ipmnt
 *   mntvfs -> fileset ipimap+ -> aggregate ipbmap -> aggregate ipaimap;
 *             fileset vfs     -> vp(1) <-> ... <-> vp(n) <->vproot;
 */

#include <linux/fs.h>
#include <linux/buffer_head.h>

#include "jfs_incore.h"
#include "jfs_filsys.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_imap.h"
#include "jfs_metapage.h"
#include "jfs_debug.h"


/*
 * forward references
 */
static int chkSuper(struct super_block *);
static int logMOUNT(struct super_block *sb);

/*
 * NAME:    jfs_mount(sb)
 *
 * FUNCTION:    vfs_mount()
 *
 * PARAMETER:   sb  - super block
 *
 * RETURN:  -EBUSY  - device already mounted or open for write
 *      -EBUSY  - cvrdvp already mounted;
 *      -EBUSY  - mount table full
 *      -ENOTDIR- cvrdvp not directory on a device mount
 *      -ENXIO  - device open failure
 */
int jfs_mount(struct super_block *sb)
{
    int rc = 0;     /* Return code */
    struct jfs_sb_info *sbi = JFS_SBI(sb);
    struct inode *ipaimap = NULL;
    struct inode *ipaimap2 = NULL;
    struct inode *ipimap = NULL;
    struct inode *ipbmap = NULL;

    /*
     * read/validate superblock
     * (initialize mount inode from the superblock)
     */
    if ((rc = chkSuper(sb))) {
        goto errout20;
    }

    ipaimap = diReadSpecial(sb, AGGREGATE_I, 0);
    if (ipaimap == NULL) {
        jfs_err("jfs_mount: Failed to read AGGREGATE_I");
        rc = -EIO;
        goto errout20;
    }
    sbi->ipaimap = ipaimap;

    jfs_info("jfs_mount: ipaimap:0x%p", ipaimap);

    /*
     * initialize aggregate inode allocation map
     */
    if ((rc = diMount(ipaimap))) {
        jfs_err("jfs_mount: diMount(ipaimap) failed w/rc = %d", rc);
        goto errout21;
    }

    /*
     * open aggregate block allocation map
     */
    ipbmap = diReadSpecial(sb, BMAP_I, 0);
    if (ipbmap == NULL) {
        rc = -EIO;
        goto errout22;
    }

    jfs_info("jfs_mount: ipbmap:0x%p", ipbmap);

    sbi->ipbmap = ipbmap;

    /*
     * initialize aggregate block allocation map
     */
    if ((rc = dbMount(ipbmap))) {
        jfs_err("jfs_mount: dbMount failed w/rc = %d", rc);
        goto errout22;
    }

    /*
     * open the secondary aggregate inode allocation map
     *
     * This is a duplicate of the aggregate inode allocation map.
     *
     * hand craft a vfs in the same fashion as we did to read ipaimap.
     * By adding INOSPEREXT (32) to the inode number, we are telling
     * diReadSpecial that we are reading from the secondary aggregate
     * inode table.  This also creates a unique entry in the inode hash
     * table.
     */
    if ((sbi->mntflag & JFS_BAD_SAIT) == 0) {
        ipaimap2 = diReadSpecial(sb, AGGREGATE_I, 1);
        if (!ipaimap2) {
            jfs_err("jfs_mount: Failed to read AGGREGATE_I");
            rc = -EIO;
            goto errout35;
        }
        sbi->ipaimap2 = ipaimap2;

        jfs_info("jfs_mount: ipaimap2:0x%p", ipaimap2);

        /*
         * initialize secondary aggregate inode allocation map
         */
        if ((rc = diMount(ipaimap2))) {
            jfs_err("jfs_mount: diMount(ipaimap2) failed, rc = %d",
                rc);
            goto errout35;
        }
    } else
        /* Secondary aggregate inode table is not valid */
        sbi->ipaimap2 = NULL;

    /*
     *  mount (the only/single) fileset
     */
    /*
     * open fileset inode allocation map (aka fileset inode)
     */
    ipimap = diReadSpecial(sb, FILESYSTEM_I, 0);
    if (ipimap == NULL) {
        jfs_err("jfs_mount: Failed to read FILESYSTEM_I");
        /* open fileset secondary inode allocation map */
        rc = -EIO;
        goto errout40;
    }
    jfs_info("jfs_mount: ipimap:0x%p", ipimap);

    /* map further access of per fileset inodes by the fileset inode */
    sbi->ipimap = ipimap;

    /* initialize fileset inode allocation map */
    if ((rc = diMount(ipimap))) {
        jfs_err("jfs_mount: diMount failed w/rc = %d", rc);
        goto errout41;
    }

    goto out;

    /*
     *  unwind on error
     */
      errout41:     /* close fileset inode allocation map inode */
    diFreeSpecial(ipimap);

      errout40:     /* fileset closed */

    /* close secondary aggregate inode allocation map */
    if (ipaimap2) {
        diUnmount(ipaimap2, 1);
        diFreeSpecial(ipaimap2);
    }

      errout35:

    /* close aggregate block allocation map */
    dbUnmount(ipbmap, 1);
    diFreeSpecial(ipbmap);

      errout22:     /* close aggregate inode allocation map */

    diUnmount(ipaimap, 1);

      errout21:     /* close aggregate inodes */
    diFreeSpecial(ipaimap);
      errout20:     /* aggregate closed */

      out:

    if (rc)
        jfs_err("Mount JFS Failure: %d", rc);

    return rc;
}

/*
 * NAME:    jfs_mount_rw(sb, remount)
 *
 * FUNCTION:    Completes read-write mount, or remounts read-only volume
 *      as read-write
 */
int jfs_mount_rw(struct super_block *sb, int remount)
{
    struct jfs_sb_info *sbi = JFS_SBI(sb);
    int rc;

    /*
     * If we are re-mounting a previously read-only volume, we want to
     * re-read the inode and block maps, since fsck.jfs may have updated
     * them.
     */
    if (remount) {
        if (chkSuper(sb) || (sbi->state != FM_CLEAN))
            return -EINVAL;

        truncate_inode_pages(sbi->ipimap->i_mapping, 0);
        truncate_inode_pages(sbi->ipbmap->i_mapping, 0);
        diUnmount(sbi->ipimap, 1);
        if ((rc = diMount(sbi->ipimap))) {
            jfs_err("jfs_mount_rw: diMount failed!");
            return rc;
        }

        dbUnmount(sbi->ipbmap, 1);
        if ((rc = dbMount(sbi->ipbmap))) {
            jfs_err("jfs_mount_rw: dbMount failed!");
            return rc;
        }
    }

    /*
     * open/initialize log
     */
    if ((rc = lmLogOpen(sb)))
        return rc;

    /*
     * update file system superblock;
     */
    if ((rc = updateSuper(sb, FM_MOUNT))) {
        jfs_err("jfs_mount: updateSuper failed w/rc = %d", rc);
        lmLogClose(sb);
        return rc;
    }

    /*
     * write MOUNT log record of the file system
     */
    logMOUNT(sb);

    return rc;
}

/*
 *  chkSuper()
 *
 * validate the superblock of the file system to be mounted and
 * get the file system parameters.
 *
 * returns
 *  0 with fragsize set if check successful
 *  error code if not successful
 */
static int chkSuper(struct super_block *sb)
{
    int rc = 0;
    struct jfs_sb_info *sbi = JFS_SBI(sb);
    struct jfs_superblock *j_sb;
    struct buffer_head *bh;
    int AIM_bytesize, AIT_bytesize;
    int expected_AIM_bytesize, expected_AIT_bytesize;
    s64 AIM_byte_addr, AIT_byte_addr, fsckwsp_addr;
    s64 byte_addr_diff0, byte_addr_diff1;
    s32 bsize;

    if ((rc = readSuper(sb, &bh)))
        return rc;
    j_sb = (struct jfs_superblock *)bh->b_data;

    /*
     * validate superblock
     */
    /* validate fs signature */
    if (strncmp(j_sb->s_magic, JFS_MAGIC, 4) ||
        le32_to_cpu(j_sb->s_version) > JFS_VERSION) {
        rc = -EINVAL;
        goto out;
    }

    bsize = le32_to_cpu(j_sb->s_bsize);
#ifdef _JFS_4K
    if (bsize != PSIZE) {
        jfs_err("Currently only 4K block size supported!");
        rc = -EINVAL;
        goto out;
    }
#endif              /* _JFS_4K */

    jfs_info("superblock: flag:0x%08x state:0x%08x size:0x%Lx",
         le32_to_cpu(j_sb->s_flag), le32_to_cpu(j_sb->s_state),
         (unsigned long long) le64_to_cpu(j_sb->s_size));

    /* validate the descriptors for Secondary AIM and AIT */
    if ((j_sb->s_flag & cpu_to_le32(JFS_BAD_SAIT)) !=
        cpu_to_le32(JFS_BAD_SAIT)) {
        expected_AIM_bytesize = 2 * PSIZE;
        AIM_bytesize = lengthPXD(&(j_sb->s_aim2)) * bsize;
        expected_AIT_bytesize = 4 * PSIZE;
        AIT_bytesize = lengthPXD(&(j_sb->s_ait2)) * bsize;
        AIM_byte_addr = addressPXD(&(j_sb->s_aim2)) * bsize;
        AIT_byte_addr = addressPXD(&(j_sb->s_ait2)) * bsize;
        byte_addr_diff0 = AIT_byte_addr - AIM_byte_addr;
        fsckwsp_addr = addressPXD(&(j_sb->s_fsckpxd)) * bsize;
        byte_addr_diff1 = fsckwsp_addr - AIT_byte_addr;
        if ((AIM_bytesize != expected_AIM_bytesize) ||
            (AIT_bytesize != expected_AIT_bytesize) ||
            (byte_addr_diff0 != AIM_bytesize) ||
            (byte_addr_diff1 <= AIT_bytesize))
            j_sb->s_flag |= cpu_to_le32(JFS_BAD_SAIT);
    }

    if ((j_sb->s_flag & cpu_to_le32(JFS_GROUPCOMMIT)) !=
        cpu_to_le32(JFS_GROUPCOMMIT))
        j_sb->s_flag |= cpu_to_le32(JFS_GROUPCOMMIT);

    /* validate fs state */
    if (j_sb->s_state != cpu_to_le32(FM_CLEAN) &&
        !(sb->s_flags & MS_RDONLY)) {
        jfs_err("jfs_mount: Mount Failure: File System Dirty.");
        rc = -EINVAL;
        goto out;
    }

    sbi->state = le32_to_cpu(j_sb->s_state);
    sbi->mntflag = le32_to_cpu(j_sb->s_flag);

    /*
     * JFS always does I/O by 4K pages.  Don't tell the buffer cache
     * that we use anything else (leave s_blocksize alone).
     */
    sbi->bsize = bsize;
    sbi->l2bsize = le16_to_cpu(j_sb->s_l2bsize);

    /*
     * For now, ignore s_pbsize, l2bfactor.  All I/O going through buffer
     * cache.
     */
    sbi->nbperpage = PSIZE >> sbi->l2bsize;
    sbi->l2nbperpage = L2PSIZE - sbi->l2bsize;
    sbi->l2niperblk = sbi->l2bsize - L2DISIZE;
    if (sbi->mntflag & JFS_INLINELOG)
        sbi->logpxd = j_sb->s_logpxd;
    else {
        sbi->logdev = new_decode_dev(le32_to_cpu(j_sb->s_logdev));
        memcpy(sbi->uuid, j_sb->s_uuid, sizeof(sbi->uuid));
        memcpy(sbi->loguuid, j_sb->s_loguuid, sizeof(sbi->uuid));
    }
    sbi->fsckpxd = j_sb->s_fsckpxd;
    sbi->ait2 = j_sb->s_ait2;

      out:
    brelse(bh);
    return rc;
}


/*
 *  updateSuper()
 *
 * update synchronously superblock if it is mounted read-write.
 */
int updateSuper(struct super_block *sb, uint state)
{
    struct jfs_superblock *j_sb;
    struct jfs_sb_info *sbi = JFS_SBI(sb);
    struct buffer_head *bh;
    int rc;

    if (sbi->flag & JFS_NOINTEGRITY) {
        if (state == FM_DIRTY) {
            sbi->p_state = state;
            return 0;
        } else if (state == FM_MOUNT) {
            sbi->p_state = sbi->state;
            state = FM_DIRTY;
        } else if (state == FM_CLEAN) {
            state = sbi->p_state;
        } else
            jfs_err("updateSuper: bad state");
    } else if (sbi->state == FM_DIRTY)
        return 0;

    if ((rc = readSuper(sb, &bh)))
        return rc;

    j_sb = (struct jfs_superblock *)bh->b_data;

    j_sb->s_state = cpu_to_le32(state);
    sbi->state = state;

    if (state == FM_MOUNT) {
        /* record log's dev_t and mount serial number */
        j_sb->s_logdev = cpu_to_le32(new_encode_dev(sbi->log->bdev->bd_dev));
        j_sb->s_logserial = cpu_to_le32(sbi->log->serial);
    } else if (state == FM_CLEAN) {
        /*
         * If this volume is shared with OS/2, OS/2 will need to
         * recalculate DASD usage, since we don't deal with it.
         */
        if (j_sb->s_flag & cpu_to_le32(JFS_DASD_ENABLED))
            j_sb->s_flag |= cpu_to_le32(JFS_DASD_PRIME);
    }

    mark_buffer_dirty(bh);
    sync_dirty_buffer(bh);
    brelse(bh);

    return 0;
}


/*
 *  readSuper()
 *
 * read superblock by raw sector address
 */
int readSuper(struct super_block *sb, struct buffer_head **bpp)
{
    /* read in primary superblock */
    *bpp = sb_bread(sb, SUPER1_OFF >> sb->s_blocksize_bits);
    if (*bpp)
        return 0;

    /* read in secondary/replicated superblock */
    *bpp = sb_bread(sb, SUPER2_OFF >> sb->s_blocksize_bits);
    if (*bpp)
        return 0;

    return -EIO;
}


/*
 *  logMOUNT()
 *
 * function: write a MOUNT log record for file system.
 *
 * MOUNT record keeps logredo() from processing log records
 * for this file system past this point in log.
 * it is harmless if mount fails.
 *
 * note: MOUNT record is at aggregate level, not at fileset level,
 * since log records of previous mounts of a fileset
 * (e.g., AFTER record of extent allocation) have to be processed
 * to update block allocation map at aggregate level.
 */
static int logMOUNT(struct super_block *sb)
{
    struct jfs_log *log = JFS_SBI(sb)->log;
    struct lrd lrd;

    lrd.logtid = 0;
    lrd.backchain = 0;
    lrd.type = cpu_to_le16(LOG_MOUNT);
    lrd.length = 0;
    lrd.aggregate = cpu_to_le32(new_encode_dev(sb->s_bdev->bd_dev));
    lmLog(log, NULL, &lrd, NULL);

    return 0;
}