[PATCH] OCFS2: The Second Oracle Cluster Filesystem

[linux-2.6] / fs / ocfs2 / super.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * super.c
 *
 * load/unload driver, mount/dismount volumes
 *
 * Copyright (C) 2002, 2004 Oracle.  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; 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 021110-1307, USA.
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/statfs.h>
#include <linux/moduleparam.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/parser.h>
#include <linux/crc32.h>
#include <linux/debugfs.h>

#include <cluster/nodemanager.h>

#define MLOG_MASK_PREFIX ML_SUPER
#include <cluster/masklog.h>

#include "ocfs2.h"

/* this should be the only file to include a version 1 header */
#include "ocfs1_fs_compat.h"

#include "alloc.h"
#include "dlmglue.h"
#include "export.h"
#include "extent_map.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "localalloc.h"
#include "namei.h"
#include "slot_map.h"
#include "super.h"
#include "sysfile.h"
#include "uptodate.h"
#include "ver.h"
#include "vote.h"

#include "buffer_head_io.h"

/*
 * Globals
 */
static spinlock_t ocfs2_globals_lock = SPIN_LOCK_UNLOCKED;

static u32 osb_id;             /* Keeps track of next available OSB Id */

static kmem_cache_t *ocfs2_inode_cachep = NULL;

kmem_cache_t *ocfs2_lock_cache = NULL;

/* OCFS2 needs to schedule several differnt types of work which
 * require cluster locking, disk I/O, recovery waits, etc. Since these
 * types of work tend to be heavy we avoid using the kernel events
 * workqueue and schedule on our own. */
struct workqueue_struct *ocfs2_wq = NULL;

static struct dentry *ocfs2_debugfs_root = NULL;

MODULE_AUTHOR("Oracle");
MODULE_LICENSE("GPL");

static int ocfs2_parse_options(struct super_block *sb, char *options,
                               unsigned long *mount_opt, int is_remount);
static void ocfs2_put_super(struct super_block *sb);
static int ocfs2_mount_volume(struct super_block *sb);
static int ocfs2_remount(struct super_block *sb, int *flags, char *data);
static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err);
static int ocfs2_initialize_mem_caches(void);
static void ocfs2_free_mem_caches(void);
static void ocfs2_delete_osb(struct ocfs2_super *osb);

static int ocfs2_statfs(struct super_block *sb, struct kstatfs *buf);

static int ocfs2_sync_fs(struct super_block *sb, int wait);

static int ocfs2_init_global_system_inodes(struct ocfs2_super *osb);
static int ocfs2_init_local_system_inodes(struct ocfs2_super *osb);
static int ocfs2_release_system_inodes(struct ocfs2_super *osb);
static int ocfs2_fill_local_node_info(struct ocfs2_super *osb);
static int ocfs2_check_volume(struct ocfs2_super *osb);
static int ocfs2_verify_volume(struct ocfs2_dinode *di,
                               struct buffer_head *bh,
                               u32 sectsize);
static int ocfs2_initialize_super(struct super_block *sb,
                                  struct buffer_head *bh,
                                  int sector_size);
static int ocfs2_get_sector(struct super_block *sb,
                            struct buffer_head **bh,
                            int block,
                            int sect_size);
static void ocfs2_write_super(struct super_block *sb);
static struct inode *ocfs2_alloc_inode(struct super_block *sb);
static void ocfs2_destroy_inode(struct inode *inode);

static unsigned long long ocfs2_max_file_offset(unsigned int blockshift);

static struct super_operations ocfs2_sops = {
        .statfs         = ocfs2_statfs,
        .alloc_inode    = ocfs2_alloc_inode,
        .destroy_inode  = ocfs2_destroy_inode,
        .drop_inode     = ocfs2_drop_inode,
        .clear_inode    = ocfs2_clear_inode,
        .delete_inode   = ocfs2_delete_inode,
        .sync_fs        = ocfs2_sync_fs,
        .write_super    = ocfs2_write_super,
        .put_super      = ocfs2_put_super,
        .remount_fs     = ocfs2_remount,
};

enum {
        Opt_barrier,
        Opt_err_panic,
        Opt_err_ro,
        Opt_intr,
        Opt_nointr,
        Opt_hb_none,
        Opt_hb_local,
        Opt_data_ordered,
        Opt_data_writeback,
        Opt_err,
};

static match_table_t tokens = {
        {Opt_barrier, "barrier=%u"},
        {Opt_err_panic, "errors=panic"},
        {Opt_err_ro, "errors=remount-ro"},
        {Opt_intr, "intr"},
        {Opt_nointr, "nointr"},
        {Opt_hb_none, OCFS2_HB_NONE},
        {Opt_hb_local, OCFS2_HB_LOCAL},
        {Opt_data_ordered, "data=ordered"},
        {Opt_data_writeback, "data=writeback"},
        {Opt_err, NULL}
};

/*
 * write_super and sync_fs ripped right out of ext3.
 */
static void ocfs2_write_super(struct super_block *sb)
{
        if (down_trylock(&sb->s_lock) == 0)
                BUG();
        sb->s_dirt = 0;
}

static int ocfs2_sync_fs(struct super_block *sb, int wait)
{
        int status = 0;
        tid_t target;
        struct ocfs2_super *osb = OCFS2_SB(sb);

        sb->s_dirt = 0;

        if (ocfs2_is_hard_readonly(osb))
                return -EROFS;

        if (wait) {
                status = ocfs2_flush_truncate_log(osb);
                if (status < 0)
                        mlog_errno(status);
        } else {
                ocfs2_schedule_truncate_log_flush(osb, 0);
        }

        if (journal_start_commit(OCFS2_SB(sb)->journal->j_journal, &target)) {
                if (wait)
                        log_wait_commit(OCFS2_SB(sb)->journal->j_journal,
                                        target);
        }
        return 0;
}

static int ocfs2_init_global_system_inodes(struct ocfs2_super *osb)
{
        struct inode *new = NULL;
        int status = 0;
        int i;

        mlog_entry_void();

        new = ocfs2_iget(osb, osb->root_blkno);
        if (IS_ERR(new)) {
                status = PTR_ERR(new);
                mlog_errno(status);
                goto bail;
        }
        osb->root_inode = new;

        new = ocfs2_iget(osb, osb->system_dir_blkno);
        if (IS_ERR(new)) {
                status = PTR_ERR(new);
                mlog_errno(status);
                goto bail;
        }
        osb->sys_root_inode = new;

        for (i = OCFS2_FIRST_ONLINE_SYSTEM_INODE;
             i <= OCFS2_LAST_GLOBAL_SYSTEM_INODE; i++) {
                new = ocfs2_get_system_file_inode(osb, i, osb->slot_num);
                if (!new) {
                        ocfs2_release_system_inodes(osb);
                        status = -EINVAL;
                        mlog_errno(status);
                        /* FIXME: Should ERROR_RO_FS */
                        mlog(ML_ERROR, "Unable to load system inode %d, "
                             "possibly corrupt fs?", i);
                        goto bail;
                }
                // the array now has one ref, so drop this one
                iput(new);
        }

bail:
        mlog_exit(status);
        return status;
}

static int ocfs2_init_local_system_inodes(struct ocfs2_super *osb)
{
        struct inode *new = NULL;
        int status = 0;
        int i;

        mlog_entry_void();

        for (i = OCFS2_LAST_GLOBAL_SYSTEM_INODE + 1;
             i < NUM_SYSTEM_INODES;
             i++) {
                new = ocfs2_get_system_file_inode(osb, i, osb->slot_num);
                if (!new) {
                        ocfs2_release_system_inodes(osb);
                        status = -EINVAL;
                        mlog(ML_ERROR, "status=%d, sysfile=%d, slot=%d\n",
                             status, i, osb->slot_num);
                        goto bail;
                }
                /* the array now has one ref, so drop this one */
                iput(new);
        }

bail:
        mlog_exit(status);
        return status;
}

static int ocfs2_release_system_inodes(struct ocfs2_super *osb)
{
        int status = 0, i;
        struct inode *inode;

        mlog_entry_void();

        for (i = 0; i < NUM_SYSTEM_INODES; i++) {
                inode = osb->system_inodes[i];
                if (inode) {
                        iput(inode);
                        osb->system_inodes[i] = NULL;
                }
        }

        inode = osb->sys_root_inode;
        if (inode) {
                iput(inode);
                osb->sys_root_inode = NULL;
        }

        inode = osb->root_inode;
        if (inode) {
                iput(inode);
                osb->root_inode = NULL;
        }

        mlog_exit(status);
        return status;
}

/* We're allocating fs objects, use GFP_NOFS */
static struct inode *ocfs2_alloc_inode(struct super_block *sb)
{
        struct ocfs2_inode_info *oi;

        oi = kmem_cache_alloc(ocfs2_inode_cachep, SLAB_NOFS);
        if (!oi)
                return NULL;

        return &oi->vfs_inode;
}

static void ocfs2_destroy_inode(struct inode *inode)
{
        kmem_cache_free(ocfs2_inode_cachep, OCFS2_I(inode));
}

/* From xfs_super.c:xfs_max_file_offset
 * Copyright (c) 2000-2004 Silicon Graphics, Inc.
 */
static unsigned long long ocfs2_max_file_offset(unsigned int blockshift)
{
        unsigned int pagefactor = 1;
        unsigned int bitshift = BITS_PER_LONG - 1;

        /* Figure out maximum filesize, on Linux this can depend on
         * the filesystem blocksize (on 32 bit platforms).
         * __block_prepare_write does this in an [unsigned] long...
         *      page->index << (PAGE_CACHE_SHIFT - bbits)
         * So, for page sized blocks (4K on 32 bit platforms),
         * this wraps at around 8Tb (hence MAX_LFS_FILESIZE which is
         *      (((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1)
         * but for smaller blocksizes it is less (bbits = log2 bsize).
         * Note1: get_block_t takes a long (implicit cast from above)
         * Note2: The Large Block Device (LBD and HAVE_SECTOR_T) patch
         * can optionally convert the [unsigned] long from above into
         * an [unsigned] long long.
         */

#if BITS_PER_LONG == 32
# if defined(CONFIG_LBD)
        BUG_ON(sizeof(sector_t) != 8);
        pagefactor = PAGE_CACHE_SIZE;
        bitshift = BITS_PER_LONG;
# else
        pagefactor = PAGE_CACHE_SIZE >> (PAGE_CACHE_SHIFT - blockshift);
# endif
#endif

        return (((unsigned long long)pagefactor) << bitshift) - 1;
}

static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
{
        int incompat_features;
        int ret = 0;
        unsigned long parsed_options;
        struct ocfs2_super *osb = OCFS2_SB(sb);

        if (!ocfs2_parse_options(sb, data, &parsed_options, 1)) {
                ret = -EINVAL;
                goto out;
        }

        if ((osb->s_mount_opt & OCFS2_MOUNT_HB_LOCAL) !=
            (parsed_options & OCFS2_MOUNT_HB_LOCAL)) {
                ret = -EINVAL;
                mlog(ML_ERROR, "Cannot change heartbeat mode on remount\n");
                goto out;
        }

        if ((osb->s_mount_opt & OCFS2_MOUNT_DATA_WRITEBACK) !=
            (parsed_options & OCFS2_MOUNT_DATA_WRITEBACK)) {
                ret = -EINVAL;
                mlog(ML_ERROR, "Cannot change data mode on remount\n");
                goto out;
        }

        /* We're going to/from readonly mode. */
        if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
                /* Lock here so the check of HARD_RO and the potential
                 * setting of SOFT_RO is atomic. */
                spin_lock(&osb->osb_lock);
                if (osb->osb_flags & OCFS2_OSB_HARD_RO) {
                        mlog(ML_ERROR, "Remount on readonly device is forbidden.\n");
                        ret = -EROFS;
                        goto unlock_osb;
                }

                if (*flags & MS_RDONLY) {
                        mlog(0, "Going to ro mode.\n");
                        sb->s_flags |= MS_RDONLY;
                        osb->osb_flags |= OCFS2_OSB_SOFT_RO;
                } else {
                        mlog(0, "Making ro filesystem writeable.\n");

                        if (osb->osb_flags & OCFS2_OSB_ERROR_FS) {
                                mlog(ML_ERROR, "Cannot remount RDWR "
                                     "filesystem due to previous errors.\n");
                                ret = -EROFS;
                                goto unlock_osb;
                        }
                        incompat_features = OCFS2_HAS_RO_COMPAT_FEATURE(sb, ~OCFS2_FEATURE_RO_COMPAT_SUPP);
                        if (incompat_features) {
                                mlog(ML_ERROR, "Cannot remount RDWR because "
                                     "of unsupported optional features "
                                     "(%x).\n", incompat_features);
                                ret = -EINVAL;
                                goto unlock_osb;
                        }
                        sb->s_flags &= ~MS_RDONLY;
                        osb->osb_flags &= ~OCFS2_OSB_SOFT_RO;
                }
unlock_osb:
                spin_unlock(&osb->osb_lock);
        }

        if (!ret) {
                if (!ocfs2_is_hard_readonly(osb))
                        ocfs2_set_journal_params(osb);

                /* Only save off the new mount options in case of a successful
                 * remount. */
                osb->s_mount_opt = parsed_options;
        }
out:
        return ret;
}

static int ocfs2_sb_probe(struct super_block *sb,
                          struct buffer_head **bh,
                          int *sector_size)
{
        int status = 0, tmpstat;
        struct ocfs1_vol_disk_hdr *hdr;
        struct ocfs2_dinode *di;
        int blksize;

        *bh = NULL;

        /* may be > 512 */
        *sector_size = bdev_hardsect_size(sb->s_bdev);
        if (*sector_size > OCFS2_MAX_BLOCKSIZE) {
                mlog(ML_ERROR, "Hardware sector size too large: %d (max=%d)\n",
                     *sector_size, OCFS2_MAX_BLOCKSIZE);
                status = -EINVAL;
                goto bail;
        }

        /* Can this really happen? */
        if (*sector_size < OCFS2_MIN_BLOCKSIZE)
                *sector_size = OCFS2_MIN_BLOCKSIZE;

        /* check block zero for old format */
        status = ocfs2_get_sector(sb, bh, 0, *sector_size);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
        hdr = (struct ocfs1_vol_disk_hdr *) (*bh)->b_data;
        if (hdr->major_version == OCFS1_MAJOR_VERSION) {
                mlog(ML_ERROR, "incompatible version: %u.%u\n",
                     hdr->major_version, hdr->minor_version);
                status = -EINVAL;
        }
        if (memcmp(hdr->signature, OCFS1_VOLUME_SIGNATURE,
                   strlen(OCFS1_VOLUME_SIGNATURE)) == 0) {
                mlog(ML_ERROR, "incompatible volume signature: %8s\n",
                     hdr->signature);
                status = -EINVAL;
        }
        brelse(*bh);
        *bh = NULL;
        if (status < 0) {
                mlog(ML_ERROR, "This is an ocfs v1 filesystem which must be "
                     "upgraded before mounting with ocfs v2\n");
                goto bail;
        }

        /*
         * Now check at magic offset for 512, 1024, 2048, 4096
         * blocksizes.  4096 is the maximum blocksize because it is
         * the minimum clustersize.
         */
        status = -EINVAL;
        for (blksize = *sector_size;
             blksize <= OCFS2_MAX_BLOCKSIZE;
             blksize <<= 1) {
                tmpstat = ocfs2_get_sector(sb, bh,
                                           OCFS2_SUPER_BLOCK_BLKNO,
                                           blksize);
                if (tmpstat < 0) {
                        status = tmpstat;
                        mlog_errno(status);
                        goto bail;
                }
                di = (struct ocfs2_dinode *) (*bh)->b_data;
                status = ocfs2_verify_volume(di, *bh, blksize);
                if (status >= 0)
                        goto bail;
                brelse(*bh);
                *bh = NULL;
                if (status != -EAGAIN)
                        break;
        }

bail:
        return status;
}

static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
{
        struct dentry *root;
        int status, sector_size;
        unsigned long parsed_opt;
        struct inode *inode = NULL;
        struct ocfs2_super *osb = NULL;
        struct buffer_head *bh = NULL;

        mlog_entry("%p, %p, %i", sb, data, silent);

        /* for now we only have one cluster/node, make sure we see it
         * in the heartbeat universe */
        if (!o2hb_check_local_node_heartbeating()) {
                status = -EINVAL;
                goto read_super_error;
        }

        /* probe for superblock */
        status = ocfs2_sb_probe(sb, &bh, &sector_size);
        if (status < 0) {
                mlog(ML_ERROR, "superblock probe failed!\n");
                goto read_super_error;
        }

        status = ocfs2_initialize_super(sb, bh, sector_size);
        osb = OCFS2_SB(sb);
        if (status < 0) {
                mlog_errno(status);
                goto read_super_error;
        }
        brelse(bh);
        bh = NULL;

        if (!ocfs2_parse_options(sb, data, &parsed_opt, 0)) {
                status = -EINVAL;
                goto read_super_error;
        }
        osb->s_mount_opt = parsed_opt;

        sb->s_magic = OCFS2_SUPER_MAGIC;

        /* Hard readonly mode only if: bdev_read_only, MS_RDONLY,
         * heartbeat=none */
        if (bdev_read_only(sb->s_bdev)) {
                if (!(sb->s_flags & MS_RDONLY)) {
                        status = -EACCES;
                        mlog(ML_ERROR, "Readonly device detected but readonly "
                             "mount was not specified.\n");
                        goto read_super_error;
                }

                /* You should not be able to start a local heartbeat
                 * on a readonly device. */
                if (osb->s_mount_opt & OCFS2_MOUNT_HB_LOCAL) {
                        status = -EROFS;
                        mlog(ML_ERROR, "Local heartbeat specified on readonly "
                             "device.\n");
                        goto read_super_error;
                }

                status = ocfs2_check_journals_nolocks(osb);
                if (status < 0) {
                        if (status == -EROFS)
                                mlog(ML_ERROR, "Recovery required on readonly "
                                     "file system, but write access is "
                                     "unavailable.\n");
                        else
                                mlog_errno(status);                     
                        goto read_super_error;
                }

                ocfs2_set_ro_flag(osb, 1);

                printk(KERN_NOTICE "Readonly device detected. No cluster "
                       "services will be utilized for this mount. Recovery "
                       "will be skipped.\n");
        }

        if (!ocfs2_is_hard_readonly(osb)) {
                /* If this isn't a hard readonly mount, then we need
                 * to make sure that heartbeat is in a valid state,
                 * and that we mark ourselves soft readonly is -oro
                 * was specified. */
                if (!(osb->s_mount_opt & OCFS2_MOUNT_HB_LOCAL)) {
                        mlog(ML_ERROR, "No heartbeat for device (%s)\n",
                             sb->s_id);
                        status = -EINVAL;
                        goto read_super_error;
                }

                if (sb->s_flags & MS_RDONLY)
                        ocfs2_set_ro_flag(osb, 0);
        }

        osb->osb_debug_root = debugfs_create_dir(osb->uuid_str,
                                                 ocfs2_debugfs_root);
        if (!osb->osb_debug_root) {
                status = -EINVAL;
                mlog(ML_ERROR, "Unable to create per-mount debugfs root.\n");
                goto read_super_error;
        }

        status = ocfs2_mount_volume(sb);
        if (osb->root_inode)
                inode = igrab(osb->root_inode);

        if (status < 0)
                goto read_super_error;

        if (!inode) {
                status = -EIO;
                mlog_errno(status);
                goto read_super_error;
        }

        root = d_alloc_root(inode);
        if (!root) {
                status = -ENOMEM;
                mlog_errno(status);
                goto read_super_error;
        }

        sb->s_root = root;

        ocfs2_complete_mount_recovery(osb);

        printk("ocfs2: Mounting device (%u,%u) on (node %d, slot %d) with %s "
               "data mode.\n",
               MAJOR(sb->s_dev), MINOR(sb->s_dev), osb->node_num,
               osb->slot_num,
               osb->s_mount_opt & OCFS2_MOUNT_DATA_WRITEBACK ? "writeback" :
               "ordered");

        atomic_set(&osb->vol_state, VOLUME_MOUNTED);
        wake_up(&osb->osb_mount_event);

        mlog_exit(status);
        return status;

read_super_error:
        if (bh != NULL)
                brelse(bh);

        if (inode)
                iput(inode);

        if (osb) {
                atomic_set(&osb->vol_state, VOLUME_DISABLED);
                wake_up(&osb->osb_mount_event);
                ocfs2_dismount_volume(sb, 1);
        }

        mlog_exit(status);
        return status;
}

static struct super_block *ocfs2_get_sb(struct file_system_type *fs_type,
                                        int flags,
                                        const char *dev_name,
                                        void *data)
{
        return get_sb_bdev(fs_type, flags, dev_name, data, ocfs2_fill_super);
}

static struct file_system_type ocfs2_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "ocfs2",
        .get_sb         = ocfs2_get_sb, /* is this called when we mount
                                        * the fs? */
        .kill_sb        = kill_block_super, /* set to the generic one
                                             * right now, but do we
                                             * need to change that? */
        .fs_flags       = FS_REQUIRES_DEV,
        .next           = NULL
};

static int ocfs2_parse_options(struct super_block *sb,
                               char *options,
                               unsigned long *mount_opt,
                               int is_remount)
{
        int status;
        char *p;

        mlog_entry("remount: %d, options: \"%s\"\n", is_remount,
                   options ? options : "(none)");

        *mount_opt = 0;

        if (!options) {
                status = 1;
                goto bail;
        }

        while ((p = strsep(&options, ",")) != NULL) {
                int token, option;
                substring_t args[MAX_OPT_ARGS];

                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_hb_local:
                        *mount_opt |= OCFS2_MOUNT_HB_LOCAL;
                        break;
                case Opt_hb_none:
                        *mount_opt &= ~OCFS2_MOUNT_HB_LOCAL;
                        break;
                case Opt_barrier:
                        if (match_int(&args[0], &option)) {
                                status = 0;
                                goto bail;
                        }
                        if (option)
                                *mount_opt |= OCFS2_MOUNT_BARRIER;
                        else
                                *mount_opt &= ~OCFS2_MOUNT_BARRIER;
                        break;
                case Opt_intr:
                        *mount_opt &= ~OCFS2_MOUNT_NOINTR;
                        break;
                case Opt_nointr:
                        *mount_opt |= OCFS2_MOUNT_NOINTR;
                        break;
                case Opt_err_panic:
                        *mount_opt |= OCFS2_MOUNT_ERRORS_PANIC;
                        break;
                case Opt_err_ro:
                        *mount_opt &= ~OCFS2_MOUNT_ERRORS_PANIC;
                        break;
                case Opt_data_ordered:
                        *mount_opt &= ~OCFS2_MOUNT_DATA_WRITEBACK;
                        break;
                case Opt_data_writeback:
                        *mount_opt |= OCFS2_MOUNT_DATA_WRITEBACK;
                        break;
                default:
                        mlog(ML_ERROR,
                             "Unrecognized mount option \"%s\" "
                             "or missing value\n", p);
                        status = 0;
                        goto bail;
                }
        }

        status = 1;

bail:
        mlog_exit(status);
        return status;
}

static int __init ocfs2_init(void)
{
        int status;

        mlog_entry_void();

        ocfs2_print_version();

        if (init_ocfs2_extent_maps())
                return -ENOMEM;

        status = init_ocfs2_uptodate_cache();
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        status = ocfs2_initialize_mem_caches();
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        ocfs2_wq = create_singlethread_workqueue("ocfs2_wq");
        if (!ocfs2_wq) {
                status = -ENOMEM;
                goto leave;
        }

        spin_lock(&ocfs2_globals_lock);
        osb_id = 0;
        spin_unlock(&ocfs2_globals_lock);

        ocfs2_debugfs_root = debugfs_create_dir("ocfs2", NULL);
        if (!ocfs2_debugfs_root) {
                status = -EFAULT;
                mlog(ML_ERROR, "Unable to create ocfs2 debugfs root.\n");
        }

leave:
        if (status < 0) {
                ocfs2_free_mem_caches();
                exit_ocfs2_uptodate_cache();
                exit_ocfs2_extent_maps();
        }

        mlog_exit(status);

        if (status >= 0) {
                return register_filesystem(&ocfs2_fs_type);
        } else
                return -1;
}

static void __exit ocfs2_exit(void)
{
        mlog_entry_void();

        if (ocfs2_wq) {
                flush_workqueue(ocfs2_wq);
                destroy_workqueue(ocfs2_wq);
        }

        debugfs_remove(ocfs2_debugfs_root);

        ocfs2_free_mem_caches();

        unregister_filesystem(&ocfs2_fs_type);

        exit_ocfs2_extent_maps();

        exit_ocfs2_uptodate_cache();

        mlog_exit_void();
}

static void ocfs2_put_super(struct super_block *sb)
{
        mlog_entry("(0x%p)\n", sb);

        ocfs2_sync_blockdev(sb);
        ocfs2_dismount_volume(sb, 0);

        mlog_exit_void();
}

static int ocfs2_statfs(struct super_block *sb, struct kstatfs *buf)
{
        struct ocfs2_super *osb;
        u32 numbits, freebits;
        int status;
        struct ocfs2_dinode *bm_lock;
        struct buffer_head *bh = NULL;
        struct inode *inode = NULL;

        mlog_entry("(%p, %p)\n", sb, buf);

        osb = OCFS2_SB(sb);

        inode = ocfs2_get_system_file_inode(osb,
                                            GLOBAL_BITMAP_SYSTEM_INODE,
                                            OCFS2_INVALID_SLOT);
        if (!inode) {
                mlog(ML_ERROR, "failed to get bitmap inode\n");
                status = -EIO;
                goto bail;
        }

        status = ocfs2_meta_lock(inode, NULL, &bh, 0);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        bm_lock = (struct ocfs2_dinode *) bh->b_data;

        numbits = le32_to_cpu(bm_lock->id1.bitmap1.i_total);
        freebits = numbits - le32_to_cpu(bm_lock->id1.bitmap1.i_used);

        buf->f_type = OCFS2_SUPER_MAGIC;
        buf->f_bsize = sb->s_blocksize;
        buf->f_namelen = OCFS2_MAX_FILENAME_LEN;
        buf->f_blocks = ((sector_t) numbits) *
                        (osb->s_clustersize >> osb->sb->s_blocksize_bits);
        buf->f_bfree = ((sector_t) freebits) *
                       (osb->s_clustersize >> osb->sb->s_blocksize_bits);
        buf->f_bavail = buf->f_bfree;
        buf->f_files = numbits;
        buf->f_ffree = freebits;

        brelse(bh);

        ocfs2_meta_unlock(inode, 0);
        status = 0;
bail:
        if (inode)
                iput(inode);

        mlog_exit(status);

        return status;
}

static void ocfs2_inode_init_once(void *data,
                                  kmem_cache_t *cachep,
                                  unsigned long flags)
{
        struct ocfs2_inode_info *oi = data;

        if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
            SLAB_CTOR_CONSTRUCTOR) {
                oi->ip_flags = 0;
                oi->ip_open_count = 0;
                spin_lock_init(&oi->ip_lock);
                ocfs2_extent_map_init(&oi->vfs_inode);
                INIT_LIST_HEAD(&oi->ip_handle_list);
                INIT_LIST_HEAD(&oi->ip_io_markers);
                oi->ip_handle = NULL;
                oi->ip_created_trans = 0;
                oi->ip_last_trans = 0;
                oi->ip_dir_start_lookup = 0;

                init_rwsem(&oi->ip_alloc_sem);
                init_MUTEX(&(oi->ip_io_sem));

                oi->ip_blkno = 0ULL;
                oi->ip_clusters = 0;

                ocfs2_lock_res_init_once(&oi->ip_rw_lockres);
                ocfs2_lock_res_init_once(&oi->ip_meta_lockres);
                ocfs2_lock_res_init_once(&oi->ip_data_lockres);

                ocfs2_metadata_cache_init(&oi->vfs_inode);

                inode_init_once(&oi->vfs_inode);
        }
}

static int ocfs2_initialize_mem_caches(void)
{
        ocfs2_inode_cachep = kmem_cache_create("ocfs2_inode_cache",
                                               sizeof(struct ocfs2_inode_info),
                                               0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
                                               ocfs2_inode_init_once, NULL);
        if (!ocfs2_inode_cachep)
                return -ENOMEM;

        ocfs2_lock_cache = kmem_cache_create("ocfs2_lock",
                                             sizeof(struct ocfs2_journal_lock),
                                             0,
                                             SLAB_NO_REAP|SLAB_HWCACHE_ALIGN,
                                             NULL, NULL);
        if (!ocfs2_lock_cache)
                return -ENOMEM;

        return 0;
}

static void ocfs2_free_mem_caches(void)
{
        if (ocfs2_inode_cachep)
                kmem_cache_destroy(ocfs2_inode_cachep);
        if (ocfs2_lock_cache)
                kmem_cache_destroy(ocfs2_lock_cache);

        ocfs2_inode_cachep = NULL;
        ocfs2_lock_cache = NULL;
}

static int ocfs2_get_sector(struct super_block *sb,
                            struct buffer_head **bh,
                            int block,
                            int sect_size)
{
        if (!sb_set_blocksize(sb, sect_size)) {
                mlog(ML_ERROR, "unable to set blocksize\n");
                return -EIO;
        }

        *bh = sb_getblk(sb, block);
        if (!*bh) {
                mlog_errno(-EIO);
                return -EIO;
        }
        lock_buffer(*bh);
        if (!buffer_dirty(*bh))
                clear_buffer_uptodate(*bh);
        unlock_buffer(*bh);
        ll_rw_block(READ, 1, bh);
        wait_on_buffer(*bh);
        return 0;
}

/* ocfs2 1.0 only allows one cluster and node identity per kernel image. */
static int ocfs2_fill_local_node_info(struct ocfs2_super *osb)
{
        int status;

        /* XXX hold a ref on the node while mounte?  easy enough, if
         * desirable. */
        osb->node_num = o2nm_this_node();
        if (osb->node_num == O2NM_MAX_NODES) {
                mlog(ML_ERROR, "could not find this host's node number\n");
                status = -ENOENT;
                goto bail;
        }

        mlog(ML_NOTICE, "I am node %d\n", osb->node_num);

        status = 0;
bail:
        return status;
}

static int ocfs2_mount_volume(struct super_block *sb)
{
        int status = 0;
        int unlock_super = 0;
        struct ocfs2_super *osb = OCFS2_SB(sb);

        mlog_entry_void();

        if (ocfs2_is_hard_readonly(osb))
                goto leave;

        status = ocfs2_fill_local_node_info(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        status = ocfs2_register_hb_callbacks(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        status = ocfs2_dlm_init(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        /* requires vote_thread to be running. */
        status = ocfs2_register_net_handlers(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        status = ocfs2_super_lock(osb, 1);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }
        unlock_super = 1;

        /* This will load up the node map and add ourselves to it. */
        status = ocfs2_find_slot(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        ocfs2_populate_mounted_map(osb);

        /* load all node-local system inodes */
        status = ocfs2_init_local_system_inodes(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        status = ocfs2_check_volume(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        status = ocfs2_truncate_log_init(osb);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        /* This should be sent *after* we recovered our journal as it
         * will cause other nodes to unmark us as needing
         * recovery. However, we need to send it *before* dropping the
         * super block lock as otherwise their recovery threads might
         * try to clean us up while we're live! */
        status = ocfs2_request_mount_vote(osb);
        if (status < 0)
                mlog_errno(status);

leave:
        if (unlock_super)
                ocfs2_super_unlock(osb, 1);

        mlog_exit(status);
        return status;
}

/* we can't grab the goofy sem lock from inside wait_event, so we use
 * memory barriers to make sure that we'll see the null task before
 * being woken up */
static int ocfs2_recovery_thread_running(struct ocfs2_super *osb)
{
        mb();
        return osb->recovery_thread_task != NULL;
}

static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err)
{
        int tmp;
        struct ocfs2_super *osb = NULL;

        mlog_entry("(0x%p)\n", sb);

        BUG_ON(!sb);
        osb = OCFS2_SB(sb);
        BUG_ON(!osb);

        ocfs2_shutdown_local_alloc(osb);

        ocfs2_truncate_log_shutdown(osb);

        /* disable any new recovery threads and wait for any currently
         * running ones to exit. Do this before setting the vol_state. */
        down(&osb->recovery_lock);
        osb->disable_recovery = 1;
        up(&osb->recovery_lock);
        wait_event(osb->recovery_event, !ocfs2_recovery_thread_running(osb));

        /* At this point, we know that no more recovery threads can be
         * launched, so wait for any recovery completion work to
         * complete. */
        flush_workqueue(ocfs2_wq);

        ocfs2_journal_shutdown(osb);

        ocfs2_sync_blockdev(sb);

        /* No dlm means we've failed during mount, so skip all the
         * steps which depended on that to complete. */
        if (osb->dlm) {
                tmp = ocfs2_super_lock(osb, 1);
                if (tmp < 0) {
                        mlog_errno(tmp);
                        return;
                }

                tmp = ocfs2_request_umount_vote(osb);
                if (tmp < 0)
                        mlog_errno(tmp);

                if (osb->slot_num != OCFS2_INVALID_SLOT)
                        ocfs2_put_slot(osb);

                ocfs2_super_unlock(osb, 1);
        }

        ocfs2_release_system_inodes(osb);

        if (osb->dlm) {
                ocfs2_unregister_net_handlers(osb);

                ocfs2_dlm_shutdown(osb);
        }

        ocfs2_clear_hb_callbacks(osb);

        debugfs_remove(osb->osb_debug_root);

        if (!mnt_err)
                ocfs2_stop_heartbeat(osb);

        atomic_set(&osb->vol_state, VOLUME_DISMOUNTED);

        printk("ocfs2: Unmounting device (%u,%u) on (node %d)\n",
               MAJOR(osb->sb->s_dev), MINOR(osb->sb->s_dev), osb->node_num);

        ocfs2_delete_osb(osb);
        kfree(osb);
        sb->s_dev = 0;
        sb->s_fs_info = NULL;
}

static int ocfs2_setup_osb_uuid(struct ocfs2_super *osb, const unsigned char *uuid,
                                unsigned uuid_bytes)
{
        int i, ret;
        char *ptr;

        BUG_ON(uuid_bytes != OCFS2_VOL_UUID_LEN);

        osb->uuid_str = kcalloc(1, OCFS2_VOL_UUID_LEN * 2 + 1, GFP_KERNEL);
        if (osb->uuid_str == NULL)
                return -ENOMEM;

        memcpy(osb->uuid, uuid, OCFS2_VOL_UUID_LEN);

        for (i = 0, ptr = osb->uuid_str; i < OCFS2_VOL_UUID_LEN; i++) {
                /* print with null */
                ret = snprintf(ptr, 3, "%02X", uuid[i]);
                if (ret != 2) /* drop super cleans up */
                        return -EINVAL;
                /* then only advance past the last char */
                ptr += 2;
        }

        return 0;
}

static int ocfs2_initialize_super(struct super_block *sb,
                                  struct buffer_head *bh,
                                  int sector_size)
{
        int status = 0;
        int i;
        struct ocfs2_dinode *di = NULL;
        struct inode *inode = NULL;
        struct buffer_head *bitmap_bh = NULL;
        struct ocfs2_journal *journal;
        __le32 uuid_net_key;
        struct ocfs2_super *osb;

        mlog_entry_void();

        osb = kcalloc(1, sizeof(struct ocfs2_super), GFP_KERNEL);
        if (!osb) {
                status = -ENOMEM;
                mlog_errno(status);
                goto bail;
        }

        sb->s_fs_info = osb;
        sb->s_op = &ocfs2_sops;
        sb->s_export_op = &ocfs2_export_ops;
        sb->s_flags |= MS_NOATIME;
        /* this is needed to support O_LARGEFILE */
        sb->s_maxbytes = ocfs2_max_file_offset(sb->s_blocksize_bits);

        osb->sb = sb;
        /* Save off for ocfs2_rw_direct */
        osb->s_sectsize_bits = blksize_bits(sector_size);
        if (!osb->s_sectsize_bits)
                BUG();

        osb->net_response_ids = 0;
        spin_lock_init(&osb->net_response_lock);
        INIT_LIST_HEAD(&osb->net_response_list);

        INIT_LIST_HEAD(&osb->osb_net_handlers);
        init_waitqueue_head(&osb->recovery_event);
        spin_lock_init(&osb->vote_task_lock);
        init_waitqueue_head(&osb->vote_event);
        osb->vote_work_sequence = 0;
        osb->vote_wake_sequence = 0;
        INIT_LIST_HEAD(&osb->blocked_lock_list);
        osb->blocked_lock_count = 0;
        INIT_LIST_HEAD(&osb->vote_list);
        spin_lock_init(&osb->osb_lock);

        atomic_set(&osb->alloc_stats.moves, 0);
        atomic_set(&osb->alloc_stats.local_data, 0);
        atomic_set(&osb->alloc_stats.bitmap_data, 0);
        atomic_set(&osb->alloc_stats.bg_allocs, 0);
        atomic_set(&osb->alloc_stats.bg_extends, 0);

        ocfs2_init_node_maps(osb);

        snprintf(osb->dev_str, sizeof(osb->dev_str), "%u,%u",
                 MAJOR(osb->sb->s_dev), MINOR(osb->sb->s_dev));

        init_MUTEX(&osb->recovery_lock);

        osb->disable_recovery = 0;
        osb->recovery_thread_task = NULL;

        init_waitqueue_head(&osb->checkpoint_event);
        atomic_set(&osb->needs_checkpoint, 0);

        osb->node_num = O2NM_INVALID_NODE_NUM;
        osb->slot_num = OCFS2_INVALID_SLOT;

        osb->local_alloc_state = OCFS2_LA_UNUSED;
        osb->local_alloc_bh = NULL;

        ocfs2_setup_hb_callbacks(osb);

        init_waitqueue_head(&osb->osb_mount_event);

        osb->vol_label = kmalloc(OCFS2_MAX_VOL_LABEL_LEN, GFP_KERNEL);
        if (!osb->vol_label) {
                mlog(ML_ERROR, "unable to alloc vol label\n");
                status = -ENOMEM;
                goto bail;
        }

        osb->uuid = kmalloc(OCFS2_VOL_UUID_LEN, GFP_KERNEL);
        if (!osb->uuid) {
                mlog(ML_ERROR, "unable to alloc uuid\n");
                status = -ENOMEM;
                goto bail;
        }

        di = (struct ocfs2_dinode *)bh->b_data;

        osb->max_slots = le16_to_cpu(di->id2.i_super.s_max_slots);
        if (osb->max_slots > OCFS2_MAX_SLOTS || osb->max_slots == 0) {
                mlog(ML_ERROR, "Invalid number of node slots (%u)\n",
                     osb->max_slots);
                status = -EINVAL;
                goto bail;
        }
        mlog(ML_NOTICE, "max_slots for this device: %u\n", osb->max_slots);

        osb->s_feature_compat =
                le32_to_cpu(OCFS2_RAW_SB(di)->s_feature_compat);
        osb->s_feature_ro_compat =
                le32_to_cpu(OCFS2_RAW_SB(di)->s_feature_ro_compat);
        osb->s_feature_incompat =
                le32_to_cpu(OCFS2_RAW_SB(di)->s_feature_incompat);

        if ((i = OCFS2_HAS_INCOMPAT_FEATURE(osb->sb, ~OCFS2_FEATURE_INCOMPAT_SUPP))) {
                mlog(ML_ERROR, "couldn't mount because of unsupported "
                     "optional features (%x).\n", i);
                status = -EINVAL;
                goto bail;
        }
        if (!(osb->sb->s_flags & MS_RDONLY) &&
            (i = OCFS2_HAS_RO_COMPAT_FEATURE(osb->sb, ~OCFS2_FEATURE_RO_COMPAT_SUPP))) {
                mlog(ML_ERROR, "couldn't mount RDWR because of "
                     "unsupported optional features (%x).\n", i);
                status = -EINVAL;
                goto bail;
        }

        get_random_bytes(&osb->s_next_generation, sizeof(u32));

        /* FIXME
         * This should be done in ocfs2_journal_init(), but unknown
         * ordering issues will cause the filesystem to crash.
         * If anyone wants to figure out what part of the code
         * refers to osb->journal before ocfs2_journal_init() is run,
         * be my guest.
         */
        /* initialize our journal structure */

        journal = kcalloc(1, sizeof(struct ocfs2_journal), GFP_KERNEL);
        if (!journal) {
                mlog(ML_ERROR, "unable to alloc journal\n");
                status = -ENOMEM;
                goto bail;
        }
        osb->journal = journal;
        journal->j_osb = osb;

        atomic_set(&journal->j_num_trans, 0);
        init_rwsem(&journal->j_trans_barrier);
        init_waitqueue_head(&journal->j_checkpointed);
        spin_lock_init(&journal->j_lock);
        journal->j_trans_id = (unsigned long) 1;
        INIT_LIST_HEAD(&journal->j_la_cleanups);
        INIT_WORK(&journal->j_recovery_work, ocfs2_complete_recovery, osb);
        journal->j_state = OCFS2_JOURNAL_FREE;

        /* get some pseudo constants for clustersize bits */
        osb->s_clustersize_bits =
                le32_to_cpu(di->id2.i_super.s_clustersize_bits);
        osb->s_clustersize = 1 << osb->s_clustersize_bits;
        mlog(0, "clusterbits=%d\n", osb->s_clustersize_bits);

        if (osb->s_clustersize < OCFS2_MIN_CLUSTERSIZE ||
            osb->s_clustersize > OCFS2_MAX_CLUSTERSIZE) {
                mlog(ML_ERROR, "Volume has invalid cluster size (%d)\n",
                     osb->s_clustersize);
                status = -EINVAL;
                goto bail;
        }

        if (ocfs2_clusters_to_blocks(osb->sb, le32_to_cpu(di->i_clusters) - 1)
            > (u32)~0UL) {
                mlog(ML_ERROR, "Volume might try to write to blocks beyond "
                     "what jbd can address in 32 bits.\n");
                status = -EINVAL;
                goto bail;
        }

        if (ocfs2_setup_osb_uuid(osb, di->id2.i_super.s_uuid,
                                 sizeof(di->id2.i_super.s_uuid))) {
                mlog(ML_ERROR, "Out of memory trying to setup our uuid.\n");
                status = -ENOMEM;
                goto bail;
        }

        memcpy(&uuid_net_key, &osb->uuid[i], sizeof(osb->net_key));
        osb->net_key = le32_to_cpu(uuid_net_key);

        strncpy(osb->vol_label, di->id2.i_super.s_label, 63);
        osb->vol_label[63] = '\0';
        osb->root_blkno = le64_to_cpu(di->id2.i_super.s_root_blkno);
        osb->system_dir_blkno = le64_to_cpu(di->id2.i_super.s_system_dir_blkno);
        osb->first_cluster_group_blkno =
                le64_to_cpu(di->id2.i_super.s_first_cluster_group);
        osb->fs_generation = le32_to_cpu(di->i_fs_generation);
        mlog(0, "vol_label: %s\n", osb->vol_label);
        mlog(0, "uuid: %s\n", osb->uuid_str);
        mlog(0, "root_blkno=%"MLFu64", system_dir_blkno=%"MLFu64"\n",
             osb->root_blkno, osb->system_dir_blkno);

        osb->osb_dlm_debug = ocfs2_new_dlm_debug();
        if (!osb->osb_dlm_debug) {
                status = -ENOMEM;
                mlog_errno(status);
                goto bail;
        }

        atomic_set(&osb->vol_state, VOLUME_INIT);

        /* load root, system_dir, and all global system inodes */
        status = ocfs2_init_global_system_inodes(osb);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        /*
         * global bitmap
         */
        inode = ocfs2_get_system_file_inode(osb, GLOBAL_BITMAP_SYSTEM_INODE,
                                            OCFS2_INVALID_SLOT);
        if (!inode) {
                status = -EINVAL;
                mlog_errno(status);
                goto bail;
        }

        osb->bitmap_blkno = OCFS2_I(inode)->ip_blkno;

        status = ocfs2_read_block(osb, osb->bitmap_blkno, &bitmap_bh, 0,
                                  inode);
        iput(inode);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        di = (struct ocfs2_dinode *) bitmap_bh->b_data;
        osb->bitmap_cpg = le16_to_cpu(di->id2.i_chain.cl_cpg);
        osb->num_clusters = le32_to_cpu(di->id1.bitmap1.i_total);
        brelse(bitmap_bh);
        mlog(0, "cluster bitmap inode: %"MLFu64", clusters per group: %u\n",
             osb->bitmap_blkno, osb->bitmap_cpg);

        status = ocfs2_init_slot_info(osb);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        /*  Link this osb onto the global linked list of all osb structures. */
        /*  The Global Link List is mainted for the whole driver . */
        spin_lock(&ocfs2_globals_lock);
        osb->osb_id = osb_id;
        if (osb_id < OCFS2_MAX_OSB_ID)
                osb_id++;
        else {
                mlog(ML_ERROR, "Too many volumes mounted\n");
                status = -ENOMEM;
        }
        spin_unlock(&ocfs2_globals_lock);

bail:
        mlog_exit(status);
        return status;
}

/*
 * will return: -EAGAIN if it is ok to keep searching for superblocks
 *              -EINVAL if there is a bad superblock
 *              0 on success
 */
static int ocfs2_verify_volume(struct ocfs2_dinode *di,
                               struct buffer_head *bh,
                               u32 blksz)
{
        int status = -EAGAIN;

        mlog_entry_void();

        if (memcmp(di->i_signature, OCFS2_SUPER_BLOCK_SIGNATURE,
                   strlen(OCFS2_SUPER_BLOCK_SIGNATURE)) == 0) {
                status = -EINVAL;
                if ((1 << le32_to_cpu(di->id2.i_super.s_blocksize_bits)) != blksz) {
                        mlog(ML_ERROR, "found superblock with incorrect block "
                             "size: found %u, should be %u\n",
                             1 << le32_to_cpu(di->id2.i_super.s_blocksize_bits),
                               blksz);
                } else if (le16_to_cpu(di->id2.i_super.s_major_rev_level) !=
                           OCFS2_MAJOR_REV_LEVEL ||
                           le16_to_cpu(di->id2.i_super.s_minor_rev_level) !=
                           OCFS2_MINOR_REV_LEVEL) {
                        mlog(ML_ERROR, "found superblock with bad version: "
                             "found %u.%u, should be %u.%u\n",
                             le16_to_cpu(di->id2.i_super.s_major_rev_level),
                             le16_to_cpu(di->id2.i_super.s_minor_rev_level),
                             OCFS2_MAJOR_REV_LEVEL,
                             OCFS2_MINOR_REV_LEVEL);
                } else if (bh->b_blocknr != le64_to_cpu(di->i_blkno)) {
                        mlog(ML_ERROR, "bad block number on superblock: "
                             "found %"MLFu64", should be %llu\n",
                             di->i_blkno, (unsigned long long)bh->b_blocknr);
                } else if (le32_to_cpu(di->id2.i_super.s_clustersize_bits) < 12 ||
                            le32_to_cpu(di->id2.i_super.s_clustersize_bits) > 20) {
                        mlog(ML_ERROR, "bad cluster size found: %u\n",
                             1 << le32_to_cpu(di->id2.i_super.s_clustersize_bits));
                } else if (!le64_to_cpu(di->id2.i_super.s_root_blkno)) {
                        mlog(ML_ERROR, "bad root_blkno: 0\n");
                } else if (!le64_to_cpu(di->id2.i_super.s_system_dir_blkno)) {
                        mlog(ML_ERROR, "bad system_dir_blkno: 0\n");
                } else if (le16_to_cpu(di->id2.i_super.s_max_slots) > OCFS2_MAX_SLOTS) {
                        mlog(ML_ERROR,
                             "Superblock slots found greater than file system "
                             "maximum: found %u, max %u\n",
                             le16_to_cpu(di->id2.i_super.s_max_slots),
                             OCFS2_MAX_SLOTS);
                } else {
                        /* found it! */
                        status = 0;
                }
        }

        mlog_exit(status);
        return status;
}

static int ocfs2_check_volume(struct ocfs2_super *osb)
{
        int status = 0;
        int dirty;
        struct ocfs2_dinode *local_alloc = NULL; /* only used if we
                                                  * recover
                                                  * ourselves. */

        mlog_entry_void();

        /* Init our journal object. */
        status = ocfs2_journal_init(osb->journal, &dirty);
        if (status < 0) {
                mlog(ML_ERROR, "Could not initialize journal!\n");
                goto finally;
        }

        /* If the journal was unmounted cleanly then we don't want to
         * recover anything. Otherwise, journal_load will do that
         * dirty work for us :) */
        if (!dirty) {
                status = ocfs2_journal_wipe(osb->journal, 0);
                if (status < 0) {
                        mlog_errno(status);
                        goto finally;
                }
        } else {
                mlog(ML_NOTICE, "File system was not unmounted cleanly, "
                     "recovering volume.\n");
        }

        /* will play back anything left in the journal. */
        ocfs2_journal_load(osb->journal);

        if (dirty) {
                /* recover my local alloc if we didn't unmount cleanly. */
                status = ocfs2_begin_local_alloc_recovery(osb,
                                                          osb->slot_num,
                                                          &local_alloc);
                if (status < 0) {
                        mlog_errno(status);
                        goto finally;
                }
                /* we complete the recovery process after we've marked
                 * ourselves as mounted. */
        }

        mlog(0, "Journal loaded.\n");

        status = ocfs2_load_local_alloc(osb);
        if (status < 0) {
                mlog_errno(status);
                goto finally;
        }

        if (dirty) {
                /* Recovery will be completed after we've mounted the
                 * rest of the volume. */
                osb->dirty = 1;
                osb->local_alloc_copy = local_alloc;
                local_alloc = NULL;
        }

        /* go through each journal, trylock it and if you get the
         * lock, and it's marked as dirty, set the bit in the recover
         * map and launch a recovery thread for it. */
        status = ocfs2_mark_dead_nodes(osb);
        if (status < 0)
                mlog_errno(status);

finally:
        if (local_alloc)
                kfree(local_alloc);

        mlog_exit(status);
        return status;
}

/*
 * The routine gets called from dismount or close whenever a dismount on
 * volume is requested and the osb open count becomes 1.
 * It will remove the osb from the global list and also free up all the
 * initialized resources and fileobject.
 */
static void ocfs2_delete_osb(struct ocfs2_super *osb)
{
        mlog_entry_void();

        /* This function assumes that the caller has the main osb resource */

        if (osb->slot_info)
                ocfs2_free_slot_info(osb->slot_info);

        /* FIXME
         * This belongs in journal shutdown, but because we have to
         * allocate osb->journal at the start of ocfs2_initalize_osb(),
         * we free it here.
         */
        kfree(osb->journal);
        if (osb->local_alloc_copy)
                kfree(osb->local_alloc_copy);
        kfree(osb->uuid_str);
        ocfs2_put_dlm_debug(osb->osb_dlm_debug);
        memset(osb, 0, sizeof(struct ocfs2_super));

        mlog_exit_void();
}

/* Put OCFS2 into a readonly state, or (if the user specifies it),
 * panic(). We do not support continue-on-error operation. */
static void ocfs2_handle_error(struct super_block *sb)
{
        struct ocfs2_super *osb = OCFS2_SB(sb);

        if (osb->s_mount_opt & OCFS2_MOUNT_ERRORS_PANIC)
                panic("OCFS2: (device %s): panic forced after error\n",
                      sb->s_id);

        ocfs2_set_osb_flag(osb, OCFS2_OSB_ERROR_FS);

        if (sb->s_flags & MS_RDONLY &&
            (ocfs2_is_soft_readonly(osb) ||
             ocfs2_is_hard_readonly(osb)))
                return;

        printk(KERN_CRIT "File system is now read-only due to the potential "
               "of on-disk corruption. Please run fsck.ocfs2 once the file "
               "system is unmounted.\n");
        sb->s_flags |= MS_RDONLY;
        ocfs2_set_ro_flag(osb, 0);
}

static char error_buf[1024];

void __ocfs2_error(struct super_block *sb,
                   const char *function,
                   const char *fmt, ...)
{
        va_list args;

        va_start(args, fmt);
        vsprintf(error_buf, fmt, args);
        va_end(args);

        /* Not using mlog here because we want to show the actual
         * function the error came from. */
        printk(KERN_CRIT "OCFS2: ERROR (device %s): %s: %s\n",
               sb->s_id, function, error_buf);

        ocfs2_handle_error(sb);
}

/* Handle critical errors. This is intentionally more drastic than
 * ocfs2_handle_error, so we only use for things like journal errors,
 * etc. */
void __ocfs2_abort(struct super_block* sb,
                   const char *function,
                   const char *fmt, ...)
{
        va_list args;

        va_start(args, fmt);
        vsprintf(error_buf, fmt, args);
        va_end(args);

        printk(KERN_CRIT "OCFS2: abort (device %s): %s: %s\n",
               sb->s_id, function, error_buf);

        /* We don't have the cluster support yet to go straight to
         * hard readonly in here. Until then, we want to keep
         * ocfs2_abort() so that we can at least mark critical
         * errors.
         *
         * TODO: This should abort the journal and alert other nodes
         * that our slot needs recovery. */

        /* Force a panic(). This stinks, but it's better than letting
         * things continue without having a proper hard readonly
         * here. */
        OCFS2_SB(sb)->s_mount_opt |= OCFS2_MOUNT_ERRORS_PANIC;
        ocfs2_handle_error(sb);
}

module_init(ocfs2_init);
module_exit(ocfs2_exit);