/*
 *   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;
}