added a lot of printk output to ease writing of emulator

[linux-2.4.21-pre4.git] / fs / ext3 / super.c

/*
 *  linux/fs/ext3/super.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/jbd.h>
#include <linux/ext3_fs.h>
#include <linux/ext3_jbd.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/locks.h>
#include <linux/blkdev.h>
#include <linux/smp_lock.h>
#include <linux/random.h>
#include <asm/uaccess.h>

#ifdef CONFIG_JBD_DEBUG
static int ext3_ro_after; /* Make fs read-only after this many jiffies */
#endif

static int ext3_load_journal(struct super_block *, struct ext3_super_block *);
static int ext3_create_journal(struct super_block *, struct ext3_super_block *,
                               int);
static void ext3_commit_super (struct super_block * sb,
                               struct ext3_super_block * es,
                               int sync);
static void ext3_mark_recovery_complete(struct super_block * sb,
                                        struct ext3_super_block * es);
static void ext3_clear_journal_err(struct super_block * sb,
                                   struct ext3_super_block * es);

static int ext3_sync_fs(struct super_block * sb);

#ifdef CONFIG_JBD_DEBUG
int journal_no_write[2];

/*
 * Debug code for turning filesystems "read-only" after a specified
 * amount of time.  This is for crash/recovery testing.
 */

static void make_rdonly(kdev_t dev, int *no_write)
{
        if (dev) {
                printk(KERN_WARNING "Turning device %s read-only\n", 
                       bdevname(dev));
                *no_write = 0xdead0000 + dev;
        }
}

static void turn_fs_readonly(unsigned long arg)
{
        struct super_block *sb = (struct super_block *)arg;

        make_rdonly(sb->s_dev, &journal_no_write[0]);
        make_rdonly(EXT3_SB(sb)->s_journal->j_dev, &journal_no_write[1]);
        wake_up(&EXT3_SB(sb)->ro_wait_queue);
}

static void setup_ro_after(struct super_block *sb)
{
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        init_timer(&sbi->turn_ro_timer);
        if (ext3_ro_after) {
                printk(KERN_DEBUG "fs will go read-only in %d jiffies\n",
                       ext3_ro_after);
                init_waitqueue_head(&sbi->ro_wait_queue);
                journal_no_write[0] = 0;
                journal_no_write[1] = 0;
                sbi->turn_ro_timer.function = turn_fs_readonly;
                sbi->turn_ro_timer.data = (unsigned long)sb;
                sbi->turn_ro_timer.expires = jiffies + ext3_ro_after;
                ext3_ro_after = 0;
                add_timer(&sbi->turn_ro_timer);
        }
}

static void clear_ro_after(struct super_block *sb)
{
        del_timer_sync(&EXT3_SB(sb)->turn_ro_timer);
        journal_no_write[0] = 0;
        journal_no_write[1] = 0;
        ext3_ro_after = 0;
}
#else
#define setup_ro_after(sb)      do {} while (0)
#define clear_ro_after(sb)      do {} while (0)
#endif


static char error_buf[1024];

/* Determine the appropriate response to ext3_error on a given filesystem */

static int ext3_error_behaviour(struct super_block *sb)
{
        /* First check for mount-time options */
        if (test_opt (sb, ERRORS_PANIC))
                return EXT3_ERRORS_PANIC;
        if (test_opt (sb, ERRORS_RO))
                return EXT3_ERRORS_RO;
        if (test_opt (sb, ERRORS_CONT))
                return EXT3_ERRORS_CONTINUE;
        
        /* If no overrides were specified on the mount, then fall back
         * to the default behaviour set in the filesystem's superblock
         * on disk. */
        switch (le16_to_cpu(sb->u.ext3_sb.s_es->s_errors)) {
        case EXT3_ERRORS_PANIC:
                return EXT3_ERRORS_PANIC;
        case EXT3_ERRORS_RO:
                return EXT3_ERRORS_RO;
        default:
                break;
        }
        return EXT3_ERRORS_CONTINUE;
}

/* Deal with the reporting of failure conditions on a filesystem such as
 * inconsistencies detected or read IO failures.
 *
 * On ext2, we can store the error state of the filesystem in the
 * superblock.  That is not possible on ext3, because we may have other
 * write ordering constraints on the superblock which prevent us from
 * writing it out straight away; and given that the journal is about to
 * be aborted, we can't rely on the current, or future, transactions to
 * write out the superblock safely.
 *
 * We'll just use the journal_abort() error code to record an error in
 * the journal instead.  On recovery, the journal will compain about
 * that error until we've noted it down and cleared it.
 */

static void ext3_handle_error(struct super_block *sb)
{
        struct ext3_super_block *es = EXT3_SB(sb)->s_es;

        EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
        es->s_state |= cpu_to_le32(EXT3_ERROR_FS);

        if (sb->s_flags & MS_RDONLY)
                return;

        if (ext3_error_behaviour(sb) != EXT3_ERRORS_CONTINUE) {
                EXT3_SB(sb)->s_mount_opt |= EXT3_MOUNT_ABORT;
                journal_abort(EXT3_SB(sb)->s_journal, -EIO);
        }

        if (ext3_error_behaviour(sb) == EXT3_ERRORS_PANIC) 
                panic ("EXT3-fs (device %s): panic forced after error\n",
                       bdevname(sb->s_dev));

        if (ext3_error_behaviour(sb) == EXT3_ERRORS_RO) {
                printk (KERN_CRIT "Remounting filesystem read-only\n");
                sb->s_flags |= MS_RDONLY;
        }

        ext3_commit_super(sb, es, 1);
}

void ext3_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);

        printk (KERN_CRIT "EXT3-fs error (device %s): %s: %s\n",
                bdevname(sb->s_dev), function, error_buf);

        ext3_handle_error(sb);
}

const char *ext3_decode_error(struct super_block * sb, int errno, char nbuf[16])
{
        char *errstr = NULL;
        
        switch (errno) {
        case -EIO:
                errstr = "IO failure";
                break;
        case -ENOMEM:
                errstr = "Out of memory";
                break;
        case -EROFS:
                if (!sb || EXT3_SB(sb)->s_journal->j_flags & JFS_ABORT)
                        errstr = "Journal has aborted";
                else
                        errstr = "Readonly filesystem";
                break;
        default:
                /* If the caller passed in an extra buffer for unknown
                 * errors, textualise them now.  Else we just return
                 * NULL. */
                if (nbuf) {
                        /* Check for truncated error codes... */
                        if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
                                errstr = nbuf;
                }
                
                break;
        }

        return errstr;
}

/* __ext3_std_error decodes expected errors from journaling functions
 * automatically and invokes the appropriate error response.  */

void __ext3_std_error (struct super_block * sb, const char * function,
                       int errno)
{
        char nbuf[16];
        const char *errstr = ext3_decode_error(sb, errno, nbuf);

        printk (KERN_CRIT "EXT3-fs error (device %s) in %s: %s\n",
                bdevname(sb->s_dev), function, errstr);
        
        ext3_handle_error(sb);
}

/*
 * ext3_abort is a much stronger failure handler than ext3_error.  The
 * abort function may be used to deal with unrecoverable failures such
 * as journal IO errors or ENOMEM at a critical moment in log management.
 *
 * We unconditionally force the filesystem into an ABORT|READONLY state,
 * unless the error response on the fs has been set to panic in which
 * case we take the easy way out and panic immediately.
 */

void ext3_abort (struct super_block * sb, const char * function,
                 const char * fmt, ...)
{
        va_list args;

        printk (KERN_CRIT "ext3_abort called.\n");

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

        if (ext3_error_behaviour(sb) == EXT3_ERRORS_PANIC)
                panic ("EXT3-fs panic (device %s): %s: %s\n",
                       bdevname(sb->s_dev), function, error_buf);

        printk (KERN_CRIT "EXT3-fs abort (device %s): %s: %s\n",
                bdevname(sb->s_dev), function, error_buf);

        if (sb->s_flags & MS_RDONLY)
                return;
        
        printk (KERN_CRIT "Remounting filesystem read-only\n");
        sb->u.ext3_sb.s_mount_state |= EXT3_ERROR_FS;
        sb->s_flags |= MS_RDONLY;
        sb->u.ext3_sb.s_mount_opt |= EXT3_MOUNT_ABORT;
        journal_abort(EXT3_SB(sb)->s_journal, -EIO);
}

/* Deal with the reporting of failure conditions while running, such as
 * inconsistencies in operation or invalid system states.
 *
 * Use ext3_error() for cases of invalid filesystem states, as that will
 * record an error on disk and force a filesystem check on the next boot.
 */
NORET_TYPE void ext3_panic (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);

        /* this is to prevent panic from syncing this filesystem */
        /* AKPM: is this sufficient? */
        sb->s_flags |= MS_RDONLY;
        panic ("EXT3-fs panic (device %s): %s: %s\n",
               bdevname(sb->s_dev), function, error_buf);
}

void ext3_warning (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_WARNING "EXT3-fs warning (device %s): %s: %s\n",
                bdevname(sb->s_dev), function, error_buf);
}

void ext3_update_dynamic_rev(struct super_block *sb)
{
        struct ext3_super_block *es = EXT3_SB(sb)->s_es;

        if (le32_to_cpu(es->s_rev_level) > EXT3_GOOD_OLD_REV)
                return;

        ext3_warning(sb, __FUNCTION__,
                     "updating to rev %d because of new feature flag, "
                     "running e2fsck is recommended",
                     EXT3_DYNAMIC_REV);

        es->s_first_ino = cpu_to_le32(EXT3_GOOD_OLD_FIRST_INO);
        es->s_inode_size = cpu_to_le16(EXT3_GOOD_OLD_INODE_SIZE);
        es->s_rev_level = cpu_to_le32(EXT3_DYNAMIC_REV);
        /* leave es->s_feature_*compat flags alone */
        /* es->s_uuid will be set by e2fsck if empty */

        /*
         * The rest of the superblock fields should be zero, and if not it
         * means they are likely already in use, so leave them alone.  We
         * can leave it up to e2fsck to clean up any inconsistencies there.
         */
}

/*
 * Open the external journal device
 */
static struct block_device *ext3_blkdev_get(kdev_t dev)
{
        struct block_device *bdev;
        int err = -ENODEV;

        bdev = bdget(kdev_t_to_nr(dev));
        if (bdev == NULL)
                goto fail;
        err = blkdev_get(bdev, FMODE_READ|FMODE_WRITE, 0, BDEV_FS);
        if (err < 0)
                goto fail;
        return bdev;

fail:
        printk(KERN_ERR "EXT3: failed to open journal device %s: %d\n",
                        bdevname(dev), err);
        return NULL;
}

/*
 * Release the journal device
 */
static int ext3_blkdev_put(struct block_device *bdev)
{
        return blkdev_put(bdev, BDEV_FS);
}

static int ext3_blkdev_remove(struct ext3_sb_info *sbi)
{
        struct block_device *bdev;
        int ret = -ENODEV;

        bdev = sbi->journal_bdev;
        if (bdev) {
                ret = ext3_blkdev_put(bdev);
                sbi->journal_bdev = 0;
        }
        return ret;
}

#define orphan_list_entry(l) list_entry((l), struct inode, u.ext3_i.i_orphan)

static void dump_orphan_list(struct super_block *sb, struct ext3_sb_info *sbi)
{
        struct list_head *l;
        
        printk(KERN_ERR "sb orphan head is %d\n", 
               le32_to_cpu(sbi->s_es->s_last_orphan));
        
        printk(KERN_ERR "sb_info orphan list:\n");
        list_for_each(l, &sbi->s_orphan) {
                struct inode *inode = orphan_list_entry(l);
                printk(KERN_ERR "  "
                       "inode 0x%04x:%ld at %p: mode %o, nlink %d, next %d\n",
                       inode->i_dev, inode->i_ino, inode,
                       inode->i_mode, inode->i_nlink, 
                       le32_to_cpu(NEXT_ORPHAN(inode)));
        }
}

void ext3_put_super (struct super_block * sb)
{
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        struct ext3_super_block *es = sbi->s_es;
        kdev_t j_dev = sbi->s_journal->j_dev;
        int i;

        journal_destroy(sbi->s_journal);
        if (!(sb->s_flags & MS_RDONLY)) {
                EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
                es->s_state = le16_to_cpu(sbi->s_mount_state);
                BUFFER_TRACE(sbi->s_sbh, "marking dirty");
                mark_buffer_dirty(sbi->s_sbh);
                ext3_commit_super(sb, es, 1);
        }

        for (i = 0; i < sbi->s_gdb_count; i++)
                brelse(sbi->s_group_desc[i]);
        kfree(sbi->s_group_desc);
        for (i = 0; i < EXT3_MAX_GROUP_LOADED; i++)
                brelse(sbi->s_inode_bitmap[i]);
        for (i = 0; i < EXT3_MAX_GROUP_LOADED; i++)
                brelse(sbi->s_block_bitmap[i]);
        brelse(sbi->s_sbh);

        /* Debugging code just in case the in-memory inode orphan list
         * isn't empty.  The on-disk one can be non-empty if we've
         * detected an error and taken the fs readonly, but the
         * in-memory list had better be clean by this point. */
        if (!list_empty(&sbi->s_orphan))
                dump_orphan_list(sb, sbi);
        J_ASSERT(list_empty(&sbi->s_orphan));

        invalidate_buffers(sb->s_dev);
        if (j_dev != sb->s_dev) {
                /*
                 * Invalidate the journal device's buffers.  We don't want them
                 * floating about in memory - the physical journal device may
                 * hotswapped, and it breaks the `ro-after' testing code.
                 */
                fsync_no_super(j_dev);
                invalidate_buffers(j_dev);
                ext3_blkdev_remove(sbi);
        }
        clear_ro_after(sb);

        return;
}

static struct super_operations ext3_sops = {
        read_inode:     ext3_read_inode,        /* BKL held */
        write_inode:    ext3_write_inode,       /* BKL not held.  Don't need */
        dirty_inode:    ext3_dirty_inode,       /* BKL not held.  We take it */
        put_inode:      ext3_put_inode,         /* BKL not held.  Don't need */
        delete_inode:   ext3_delete_inode,      /* BKL not held.  We take it */
        put_super:      ext3_put_super,         /* BKL held */
        write_super:    ext3_write_super,       /* BKL held */
        sync_fs:        ext3_sync_fs,
        write_super_lockfs: ext3_write_super_lockfs, /* BKL not held. Take it */
        unlockfs:       ext3_unlockfs,          /* BKL not held.  We take it */
        statfs:         ext3_statfs,            /* BKL held */
        remount_fs:     ext3_remount,           /* BKL held */
};

static int want_value(char *value, char *option)
{
        if (!value || !*value) {
                printk(KERN_NOTICE "EXT3-fs: the %s option needs an argument\n",
                       option);
                return -1;
        }
        return 0;
}

static int want_null_value(char *value, char *option)
{
        if (*value) {
                printk(KERN_NOTICE "EXT3-fs: Invalid %s argument: %s\n",
                       option, value);
                return -1;
        }
        return 0;
}

static int want_numeric(char *value, char *option, unsigned long *number)
{
        if (want_value(value, option))
                return -1;
        *number = simple_strtoul(value, &value, 0);
        if (want_null_value(value, option))
                return -1;
        return 0;
}

/*
 * This function has been shamelessly adapted from the msdos fs
 */
static int parse_options (char * options, unsigned long * sb_block,
                          struct ext3_sb_info *sbi,
                          unsigned long * inum,
                          int is_remount)
{
        unsigned long *mount_options = &sbi->s_mount_opt;
        uid_t *resuid = &sbi->s_resuid;
        gid_t *resgid = &sbi->s_resgid;
        char * this_char;
        char * value;

        if (!options)
                return 1;
        for (this_char = strtok (options, ",");
             this_char != NULL;
             this_char = strtok (NULL, ",")) {
                if ((value = strchr (this_char, '=')) != NULL)
                        *value++ = 0;
                if (!strcmp (this_char, "bsddf"))
                        clear_opt (*mount_options, MINIX_DF);
                else if (!strcmp (this_char, "nouid32")) {
                        set_opt (*mount_options, NO_UID32);
                }
                else if (!strcmp (this_char, "abort"))
                        set_opt (*mount_options, ABORT);
                else if (!strcmp (this_char, "check")) {
                        if (!value || !*value || !strcmp (value, "none"))
                                clear_opt (*mount_options, CHECK);
                        else
#ifdef CONFIG_EXT3_CHECK
                                set_opt (*mount_options, CHECK);
#else
                                printk(KERN_ERR 
                                       "EXT3 Check option not supported\n");
#endif
                }
                else if (!strcmp (this_char, "debug"))
                        set_opt (*mount_options, DEBUG);
                else if (!strcmp (this_char, "errors")) {
                        if (want_value(value, "errors"))
                                return 0;
                        if (!strcmp (value, "continue")) {
                                clear_opt (*mount_options, ERRORS_RO);
                                clear_opt (*mount_options, ERRORS_PANIC);
                                set_opt (*mount_options, ERRORS_CONT);
                        }
                        else if (!strcmp (value, "remount-ro")) {
                                clear_opt (*mount_options, ERRORS_CONT);
                                clear_opt (*mount_options, ERRORS_PANIC);
                                set_opt (*mount_options, ERRORS_RO);
                        }
                        else if (!strcmp (value, "panic")) {
                                clear_opt (*mount_options, ERRORS_CONT);
                                clear_opt (*mount_options, ERRORS_RO);
                                set_opt (*mount_options, ERRORS_PANIC);
                        }
                        else {
                                printk (KERN_ERR
                                        "EXT3-fs: Invalid errors option: %s\n",
                                        value);
                                return 0;
                        }
                }
                else if (!strcmp (this_char, "grpid") ||
                         !strcmp (this_char, "bsdgroups"))
                        set_opt (*mount_options, GRPID);
                else if (!strcmp (this_char, "minixdf"))
                        set_opt (*mount_options, MINIX_DF);
                else if (!strcmp (this_char, "nocheck"))
                        clear_opt (*mount_options, CHECK);
                else if (!strcmp (this_char, "nogrpid") ||
                         !strcmp (this_char, "sysvgroups"))
                        clear_opt (*mount_options, GRPID);
                else if (!strcmp (this_char, "resgid")) {
                        unsigned long v;
                        if (want_numeric(value, "resgid", &v))
                                return 0;
                        *resgid = v;
                }
                else if (!strcmp (this_char, "resuid")) {
                        unsigned long v;
                        if (want_numeric(value, "resuid", &v))
                                return 0;
                        *resuid = v;
                }
                else if (!strcmp (this_char, "sb")) {
                        if (want_numeric(value, "sb", sb_block))
                                return 0;
                }
#ifdef CONFIG_JBD_DEBUG
                else if (!strcmp (this_char, "ro-after")) {
                        unsigned long v;
                        if (want_numeric(value, "ro-after", &v))
                                return 0;
                        ext3_ro_after = v;
                }
#endif
                /* Silently ignore the quota options */
                else if (!strcmp (this_char, "grpquota")
                         || !strcmp (this_char, "noquota")
                         || !strcmp (this_char, "quota")
                         || !strcmp (this_char, "usrquota"))
                        /* Don't do anything ;-) */ ;
                else if (!strcmp (this_char, "journal")) {
                        /* @@@ FIXME */
                        /* Eventually we will want to be able to create
                           a journal file here.  For now, only allow the
                           user to specify an existing inode to be the
                           journal file. */
                        if (is_remount) {
                                printk(KERN_ERR "EXT3-fs: cannot specify "
                                       "journal on remount\n");
                                return 0;
                        }

                        if (want_value(value, "journal"))
                                return 0;
                        if (!strcmp (value, "update"))
                                set_opt (*mount_options, UPDATE_JOURNAL);
                        else if (want_numeric(value, "journal", inum))
                                return 0;
                }
                else if (!strcmp (this_char, "noload"))
                        set_opt (*mount_options, NOLOAD);
                else if (!strcmp (this_char, "data")) {
                        int data_opt = 0;

                        if (want_value(value, "data"))
                                return 0;
                        if (!strcmp (value, "journal"))
                                data_opt = EXT3_MOUNT_JOURNAL_DATA;
                        else if (!strcmp (value, "ordered"))
                                data_opt = EXT3_MOUNT_ORDERED_DATA;
                        else if (!strcmp (value, "writeback"))
                                data_opt = EXT3_MOUNT_WRITEBACK_DATA;
                        else {
                                printk (KERN_ERR 
                                        "EXT3-fs: Invalid data option: %s\n",
                                        value);
                                return 0;
                        }
                        if (is_remount) {
                                if ((*mount_options & EXT3_MOUNT_DATA_FLAGS) !=
                                                        data_opt) {
                                        printk(KERN_ERR
                                               "EXT3-fs: cannot change data "
                                               "mode on remount\n");
                                        return 0;
                                }
                        } else {
                                *mount_options &= ~EXT3_MOUNT_DATA_FLAGS;
                                *mount_options |= data_opt;
                        }
                } else if (!strcmp (this_char, "commit")) {
                        unsigned long v;
                        if (want_numeric(value, "commit", &v))
                                return 0;
                        sbi->s_commit_interval = (HZ * v);
                } else {
                        printk (KERN_ERR 
                                "EXT3-fs: Unrecognized mount option %s\n",
                                this_char);
                        return 0;
                }
        }
        return 1;
}

static int ext3_setup_super(struct super_block *sb, struct ext3_super_block *es,
                            int read_only)
{
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        int res = 0;

        if (le32_to_cpu(es->s_rev_level) > EXT3_MAX_SUPP_REV) {
                printk (KERN_ERR "EXT3-fs warning: revision level too high, "
                        "forcing read-only mode\n");
                res = MS_RDONLY;
        }
        if (read_only)
                return res;
        if (!(sbi->s_mount_state & EXT3_VALID_FS))
                printk (KERN_WARNING "EXT3-fs warning: mounting unchecked fs, "
                        "running e2fsck is recommended\n");
        else if ((sbi->s_mount_state & EXT3_ERROR_FS))
                printk (KERN_WARNING
                        "EXT3-fs warning: mounting fs with errors, "
                        "running e2fsck is recommended\n");
        else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
                 le16_to_cpu(es->s_mnt_count) >=
                 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
                printk (KERN_WARNING
                        "EXT3-fs warning: maximal mount count reached, "
                        "running e2fsck is recommended\n");
        else if (le32_to_cpu(es->s_checkinterval) &&
                (le32_to_cpu(es->s_lastcheck) +
                        le32_to_cpu(es->s_checkinterval) <= CURRENT_TIME))
                printk (KERN_WARNING
                        "EXT3-fs warning: checktime reached, "
                        "running e2fsck is recommended\n");
#if 0
                /* @@@ We _will_ want to clear the valid bit if we find
                   inconsistencies, to force a fsck at reboot.  But for
                   a plain journaled filesystem we can keep it set as
                   valid forever! :) */
        es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT3_VALID_FS);
#endif
        if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
                es->s_max_mnt_count =
                        (__s16) cpu_to_le16(EXT3_DFL_MAX_MNT_COUNT);
        es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
        es->s_mtime = cpu_to_le32(CURRENT_TIME);
        ext3_update_dynamic_rev(sb);
        EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
        ext3_commit_super (sb, es, 1);
        if (test_opt (sb, DEBUG))
                printk (KERN_INFO
                        "[EXT3 FS %s, %s, bs=%lu, gc=%lu, "
                        "bpg=%lu, ipg=%lu, mo=%04lx]\n",
                        EXT3FS_VERSION, EXT3FS_DATE, sb->s_blocksize,
                        sbi->s_groups_count,
                        EXT3_BLOCKS_PER_GROUP(sb),
                        EXT3_INODES_PER_GROUP(sb),
                        sbi->s_mount_opt);
        printk(KERN_INFO "EXT3 FS " EXT3FS_VERSION ", " EXT3FS_DATE " on %s, ",
                                bdevname(sb->s_dev));
        if (EXT3_SB(sb)->s_journal->j_inode == NULL) {
                printk("external journal on %s\n",
                                bdevname(EXT3_SB(sb)->s_journal->j_dev));
        } else {
                printk("internal journal\n");
        }
#ifdef CONFIG_EXT3_CHECK
        if (test_opt (sb, CHECK)) {
                ext3_check_blocks_bitmap (sb);
                ext3_check_inodes_bitmap (sb);
        }
#endif
        setup_ro_after(sb);
        return res;
}

static int ext3_check_descriptors (struct super_block * sb)
{
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
        struct ext3_group_desc * gdp = NULL;
        int desc_block = 0;
        int i;

        ext3_debug ("Checking group descriptors");

        for (i = 0; i < sbi->s_groups_count; i++)
        {
                if ((i % EXT3_DESC_PER_BLOCK(sb)) == 0)
                        gdp = (struct ext3_group_desc *)
                                        sbi->s_group_desc[desc_block++]->b_data;
                if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
                    le32_to_cpu(gdp->bg_block_bitmap) >=
                                block + EXT3_BLOCKS_PER_GROUP(sb))
                {
                        ext3_error (sb, "ext3_check_descriptors",
                                    "Block bitmap for group %d"
                                    " not in group (block %lu)!",
                                    i, (unsigned long)
                                        le32_to_cpu(gdp->bg_block_bitmap));
                        return 0;
                }
                if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
                    le32_to_cpu(gdp->bg_inode_bitmap) >=
                                block + EXT3_BLOCKS_PER_GROUP(sb))
                {
                        ext3_error (sb, "ext3_check_descriptors",
                                    "Inode bitmap for group %d"
                                    " not in group (block %lu)!",
                                    i, (unsigned long)
                                        le32_to_cpu(gdp->bg_inode_bitmap));
                        return 0;
                }
                if (le32_to_cpu(gdp->bg_inode_table) < block ||
                    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
                    block + EXT3_BLOCKS_PER_GROUP(sb))
                {
                        ext3_error (sb, "ext3_check_descriptors",
                                    "Inode table for group %d"
                                    " not in group (block %lu)!",
                                    i, (unsigned long)
                                        le32_to_cpu(gdp->bg_inode_table));
                        return 0;
                }
                block += EXT3_BLOCKS_PER_GROUP(sb);
                gdp++;
        }
        return 1;
}


/* ext3_orphan_cleanup() walks a singly-linked list of inodes (starting at
 * the superblock) which were deleted from all directories, but held open by
 * a process at the time of a crash.  We walk the list and try to delete these
 * inodes at recovery time (only with a read-write filesystem).
 *
 * In order to keep the orphan inode chain consistent during traversal (in
 * case of crash during recovery), we link each inode into the superblock
 * orphan list_head and handle it the same way as an inode deletion during
 * normal operation (which journals the operations for us).
 *
 * We only do an iget() and an iput() on each inode, which is very safe if we
 * accidentally point at an in-use or already deleted inode.  The worst that
 * can happen in this case is that we get a "bit already cleared" message from
 * ext3_free_inode().  The only reason we would point at a wrong inode is if
 * e2fsck was run on this filesystem, and it must have already done the orphan
 * inode cleanup for us, so we can safely abort without any further action.
 */
static void ext3_orphan_cleanup (struct super_block * sb,
                                 struct ext3_super_block * es)
{
        unsigned int s_flags = sb->s_flags;
        int nr_orphans = 0, nr_truncates = 0;
        if (!es->s_last_orphan) {
                jbd_debug(4, "no orphan inodes to clean up\n");
                return;
        }

        if (s_flags & MS_RDONLY) {
                printk(KERN_INFO "EXT3-fs: %s: orphan cleanup on readonly fs\n",
                       bdevname(sb->s_dev));
                sb->s_flags &= ~MS_RDONLY;
        }

        if (sb->u.ext3_sb.s_mount_state & EXT3_ERROR_FS) {
                if (es->s_last_orphan)
                        jbd_debug(1, "Errors on filesystem, "
                                  "clearing orphan list.\n");
                es->s_last_orphan = 0;
                jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
                return;
        }

        while (es->s_last_orphan) {
                struct inode *inode;

                if (!(inode =
                      ext3_orphan_get(sb, le32_to_cpu(es->s_last_orphan)))) {
                        es->s_last_orphan = 0;
                        break;
                }

                list_add(&EXT3_I(inode)->i_orphan, &EXT3_SB(sb)->s_orphan);
                if (inode->i_nlink) {
                        printk(KERN_DEBUG "%s: truncating inode %ld to %Ld "
                                "bytes\n", __FUNCTION__, inode->i_ino,
                                inode->i_size);
                        jbd_debug(2, "truncating inode %ld to %Ld bytes\n",
                                  inode->i_ino, inode->i_size);
                        ext3_truncate(inode);
                        nr_truncates++;
                } else {
                        printk(KERN_DEBUG "%s: deleting unreferenced "
                                "inode %ld\n", __FUNCTION__, inode->i_ino);
                        jbd_debug(2, "deleting unreferenced inode %ld\n",
                                  inode->i_ino);
                        nr_orphans++;
                }
                iput(inode);  /* The delete magic happens here! */
        }

#define PLURAL(x) (x), ((x)==1) ? "" : "s"

        if (nr_orphans)
                printk(KERN_INFO "EXT3-fs: %s: %d orphan inode%s deleted\n",
                       bdevname(sb->s_dev), PLURAL(nr_orphans));
        if (nr_truncates)
                printk(KERN_INFO "EXT3-fs: %s: %d truncate%s cleaned up\n",
                       bdevname(sb->s_dev), PLURAL(nr_truncates));
        sb->s_flags = s_flags; /* Restore MS_RDONLY status */
}

#define log2(n) ffz(~(n))

/*
 * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 * We need to be 1 filesystem block less than the 2^32 sector limit.
 */
static loff_t ext3_max_size(int bits)
{
        loff_t res = EXT3_NDIR_BLOCKS;
        res += 1LL << (bits-2);
        res += 1LL << (2*(bits-2));
        res += 1LL << (3*(bits-2));
        res <<= bits;
        if (res > (512LL << 32) - (1 << bits))
                res = (512LL << 32) - (1 << bits);
        return res;
}

struct super_block * ext3_read_super (struct super_block * sb, void * data,
                                      int silent)
{
        struct buffer_head * bh;
        struct ext3_super_block *es = 0;
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        unsigned long sb_block = 1;
        unsigned long logic_sb_block = 1;
        unsigned long offset = 0;
        unsigned long journal_inum = 0;
        kdev_t dev = sb->s_dev;
        int blocksize;
        int hblock;
        int db_count;
        int i;
        int needs_recovery;

#ifdef CONFIG_JBD_DEBUG
        ext3_ro_after = 0;
#endif
        /*
         * See what the current blocksize for the device is, and
         * use that as the blocksize.  Otherwise (or if the blocksize
         * is smaller than the default) use the default.
         * This is important for devices that have a hardware
         * sectorsize that is larger than the default.
         */
        blocksize = EXT3_MIN_BLOCK_SIZE;
        hblock = get_hardsect_size(dev);
        if (blocksize < hblock)
                blocksize = hblock;

        sbi->s_mount_opt = 0;
        sbi->s_resuid = EXT3_DEF_RESUID;
        sbi->s_resgid = EXT3_DEF_RESGID;
        if (!parse_options ((char *) data, &sb_block, sbi, &journal_inum, 0)) {
                sb->s_dev = 0;
                goto out_fail;
        }

        sb->s_blocksize = blocksize;
        set_blocksize (dev, blocksize);

        /*
         * The ext3 superblock will not be buffer aligned for other than 1kB
         * block sizes.  We need to calculate the offset from buffer start.
         */
        if (blocksize != EXT3_MIN_BLOCK_SIZE) {
                logic_sb_block = (sb_block * EXT3_MIN_BLOCK_SIZE) / blocksize;
                offset = (sb_block * EXT3_MIN_BLOCK_SIZE) % blocksize;
        }

        if (!(bh = sb_bread(sb, logic_sb_block))) {
                printk (KERN_ERR "EXT3-fs: unable to read superblock\n");
                goto out_fail;
        }
        /*
         * Note: s_es must be initialized as soon as possible because
         *       some ext3 macro-instructions depend on its value
         */
        es = (struct ext3_super_block *) (((char *)bh->b_data) + offset);
        sbi->s_es = es;
        sb->s_magic = le16_to_cpu(es->s_magic);
        if (sb->s_magic != EXT3_SUPER_MAGIC) {
                if (!silent)
                        printk(KERN_ERR 
                               "VFS: Can't find ext3 filesystem on dev %s.\n",
                               bdevname(dev));
                goto failed_mount;
        }
        if (le32_to_cpu(es->s_rev_level) == EXT3_GOOD_OLD_REV &&
            (EXT3_HAS_COMPAT_FEATURE(sb, ~0U) ||
             EXT3_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
             EXT3_HAS_INCOMPAT_FEATURE(sb, ~0U)))
                printk(KERN_WARNING 
                       "EXT3-fs warning: feature flags set on rev 0 fs, "
                       "running e2fsck is recommended\n");
        /*
         * Check feature flags regardless of the revision level, since we
         * previously didn't change the revision level when setting the flags,
         * so there is a chance incompat flags are set on a rev 0 filesystem.
         */
        if ((i = EXT3_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))) {
                printk(KERN_ERR "EXT3-fs: %s: couldn't mount because of "
                       "unsupported optional features (%x).\n",
                       bdevname(dev), i);
                goto failed_mount;
        }
        if (!(sb->s_flags & MS_RDONLY) &&
            (i = EXT3_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))){
                printk(KERN_ERR "EXT3-fs: %s: couldn't mount RDWR because of "
                       "unsupported optional features (%x).\n",
                       bdevname(dev), i);
                goto failed_mount;
        }
        sb->s_blocksize_bits = le32_to_cpu(es->s_log_block_size) + 10;
        sb->s_blocksize = 1 << sb->s_blocksize_bits;

        if (sb->s_blocksize < EXT3_MIN_BLOCK_SIZE ||
            sb->s_blocksize > EXT3_MAX_BLOCK_SIZE) {
                printk(KERN_ERR 
                       "EXT3-fs: Unsupported filesystem blocksize %d on %s.\n",
                       blocksize, bdevname(dev));
                goto failed_mount;
        }

        sb->s_maxbytes = ext3_max_size(sb->s_blocksize_bits);

        if (sb->s_blocksize != blocksize) {
                blocksize = sb->s_blocksize;

                /*
                 * Make sure the blocksize for the filesystem is larger
                 * than the hardware sectorsize for the machine.
                 */
                if (sb->s_blocksize < hblock) {
                        printk(KERN_ERR "EXT3-fs: blocksize %d too small for "
                               "device blocksize %d.\n", blocksize, hblock);
                        goto failed_mount;
                }

                brelse (bh);
                set_blocksize (dev, sb->s_blocksize);
                logic_sb_block = (sb_block * EXT3_MIN_BLOCK_SIZE) / blocksize;
                offset = (sb_block * EXT3_MIN_BLOCK_SIZE) % blocksize;
                bh = sb_bread(sb, logic_sb_block);
                if (!bh) {
                        printk(KERN_ERR 
                               "EXT3-fs: Can't read superblock on 2nd try.\n");
                        return NULL;
                }
                es = (struct ext3_super_block *)(((char *)bh->b_data) + offset);
                sbi->s_es = es;
                if (es->s_magic != le16_to_cpu(EXT3_SUPER_MAGIC)) {
                        printk (KERN_ERR 
                                "EXT3-fs: Magic mismatch, very weird !\n");
                        goto failed_mount;
                }
        }

        if (le32_to_cpu(es->s_rev_level) == EXT3_GOOD_OLD_REV) {
                sbi->s_inode_size = EXT3_GOOD_OLD_INODE_SIZE;
                sbi->s_first_ino = EXT3_GOOD_OLD_FIRST_INO;
        } else {
                sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
                sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
                if (sbi->s_inode_size != EXT3_GOOD_OLD_INODE_SIZE) {
                        printk (KERN_ERR
                                "EXT3-fs: unsupported inode size: %d\n",
                                sbi->s_inode_size);
                        goto failed_mount;
                }
        }
        sbi->s_frag_size = EXT3_MIN_FRAG_SIZE <<
                                   le32_to_cpu(es->s_log_frag_size);
        if (blocksize != sbi->s_frag_size) {
                printk(KERN_ERR
                       "EXT3-fs: fragsize %lu != blocksize %u (unsupported)\n",
                       sbi->s_frag_size, blocksize);
                goto failed_mount;
        }
        sbi->s_frags_per_block = 1;
        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
        sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
        sbi->s_inodes_per_block = blocksize / EXT3_INODE_SIZE(sb);
        sbi->s_itb_per_group = sbi->s_inodes_per_group /sbi->s_inodes_per_block;
        sbi->s_desc_per_block = blocksize / sizeof(struct ext3_group_desc);
        sbi->s_sbh = bh;
        if (sbi->s_resuid == EXT3_DEF_RESUID)
                sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
        if (sbi->s_resgid == EXT3_DEF_RESGID)
                sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
        sbi->s_mount_state = le16_to_cpu(es->s_state);
        sbi->s_addr_per_block_bits = log2(EXT3_ADDR_PER_BLOCK(sb));
        sbi->s_desc_per_block_bits = log2(EXT3_DESC_PER_BLOCK(sb));

        if (sbi->s_blocks_per_group > blocksize * 8) {
                printk (KERN_ERR
                        "EXT3-fs: #blocks per group too big: %lu\n",
                        sbi->s_blocks_per_group);
                goto failed_mount;
        }
        if (sbi->s_frags_per_group > blocksize * 8) {
                printk (KERN_ERR
                        "EXT3-fs: #fragments per group too big: %lu\n",
                        sbi->s_frags_per_group);
                goto failed_mount;
        }
        if (sbi->s_inodes_per_group > blocksize * 8) {
                printk (KERN_ERR
                        "EXT3-fs: #inodes per group too big: %lu\n",
                        sbi->s_inodes_per_group);
                goto failed_mount;
        }

        sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
                               le32_to_cpu(es->s_first_data_block) +
                               EXT3_BLOCKS_PER_GROUP(sb) - 1) /
                              EXT3_BLOCKS_PER_GROUP(sb);
        db_count = (sbi->s_groups_count + EXT3_DESC_PER_BLOCK(sb) - 1) /
                   EXT3_DESC_PER_BLOCK(sb);
        sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
                                    GFP_KERNEL);
        if (sbi->s_group_desc == NULL) {
                printk (KERN_ERR "EXT3-fs: not enough memory\n");
                goto failed_mount;
        }
        for (i = 0; i < db_count; i++) {
                sbi->s_group_desc[i] = sb_bread(sb, logic_sb_block + i + 1);
                if (!sbi->s_group_desc[i]) {
                        printk (KERN_ERR "EXT3-fs: "
                                "can't read group descriptor %d\n", i);
                        db_count = i;
                        goto failed_mount2;
                }
        }
        if (!ext3_check_descriptors (sb)) {
                printk (KERN_ERR "EXT3-fs: group descriptors corrupted !\n");
                goto failed_mount2;
        }
        for (i = 0; i < EXT3_MAX_GROUP_LOADED; i++) {
                sbi->s_inode_bitmap_number[i] = 0;
                sbi->s_inode_bitmap[i] = NULL;
                sbi->s_block_bitmap_number[i] = 0;
                sbi->s_block_bitmap[i] = NULL;
        }
        sbi->s_loaded_inode_bitmaps = 0;
        sbi->s_loaded_block_bitmaps = 0;
        sbi->s_gdb_count = db_count;
        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
        /*
         * set up enough so that it can read an inode
         */
        sb->s_op = &ext3_sops;
        INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */

        sb->s_root = 0;

        needs_recovery = (es->s_last_orphan != 0 ||
                          EXT3_HAS_INCOMPAT_FEATURE(sb,
                                    EXT3_FEATURE_INCOMPAT_RECOVER));

        /*
         * The first inode we look at is the journal inode.  Don't try
         * root first: it may be modified in the journal!
         */
        if (!test_opt(sb, NOLOAD) &&
            EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
                if (ext3_load_journal(sb, es))
                        goto failed_mount2;
        } else if (journal_inum) {
                if (ext3_create_journal(sb, es, journal_inum))
                        goto failed_mount2;
        } else {
                if (!silent)
                        printk (KERN_ERR
                                "ext3: No journal on filesystem on %s\n",
                                bdevname(dev));
                goto failed_mount2;
        }

        /* We have now updated the journal if required, so we can
         * validate the data journaling mode. */
        switch (test_opt(sb, DATA_FLAGS)) {
        case 0:
                /* No mode set, assume a default based on the journal
                   capabilities: ORDERED_DATA if the journal can
                   cope, else JOURNAL_DATA */
                if (journal_check_available_features
                    (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE))
                        set_opt(sbi->s_mount_opt, ORDERED_DATA);
                else
                        set_opt(sbi->s_mount_opt, JOURNAL_DATA);
                break;

        case EXT3_MOUNT_ORDERED_DATA:
        case EXT3_MOUNT_WRITEBACK_DATA:
                if (!journal_check_available_features
                    (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)) {
                        printk(KERN_ERR "EXT3-fs: Journal does not support "
                               "requested data journaling mode\n");
                        goto failed_mount3;
                }
        default:
                break;
        }

        /*
         * The journal_load will have done any necessary log recovery,
         * so we can safely mount the rest of the filesystem now.
         */

        sb->s_root = d_alloc_root(iget(sb, EXT3_ROOT_INO));
        if (!sb->s_root || !S_ISDIR(sb->s_root->d_inode->i_mode) ||
            !sb->s_root->d_inode->i_blocks || !sb->s_root->d_inode->i_size) {
                if (sb->s_root) {
                        dput(sb->s_root);
                        sb->s_root = NULL;
                        printk(KERN_ERR
                               "EXT3-fs: corrupt root inode, run e2fsck\n");
                } else
                        printk(KERN_ERR "EXT3-fs: get root inode failed\n");
                goto failed_mount3;
        }

        ext3_setup_super (sb, es, sb->s_flags & MS_RDONLY);
        /*
         * akpm: core read_super() calls in here with the superblock locked.
         * That deadlocks, because orphan cleanup needs to lock the superblock
         * in numerous places.  Here we just pop the lock - it's relatively
         * harmless, because we are now ready to accept write_super() requests,
         * and aviro says that's the only reason for hanging onto the
         * superblock lock.
         */
        EXT3_SB(sb)->s_mount_state |= EXT3_ORPHAN_FS;
        unlock_super(sb);       /* akpm: sigh */
        ext3_orphan_cleanup(sb, es);
        lock_super(sb);
        EXT3_SB(sb)->s_mount_state &= ~EXT3_ORPHAN_FS;
        if (needs_recovery)
                printk (KERN_INFO "EXT3-fs: recovery complete.\n");
        ext3_mark_recovery_complete(sb, es);
        printk (KERN_INFO "EXT3-fs: mounted filesystem with %s data mode.\n",
                test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ? "journal":
                test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA ? "ordered":
                "writeback");

        return sb;

failed_mount3:
        journal_destroy(sbi->s_journal);
failed_mount2:
        for (i = 0; i < db_count; i++)
                brelse(sbi->s_group_desc[i]);
        kfree(sbi->s_group_desc);
failed_mount:
        ext3_blkdev_remove(sbi);
        brelse(bh);
out_fail:
        return NULL;
}

/*
 * Setup any per-fs journal parameters now.  We'll do this both on
 * initial mount, once the journal has been initialised but before we've
 * done any recovery; and again on any subsequent remount. 
 */
static void ext3_init_journal_params(struct ext3_sb_info *sbi, 
                                     journal_t *journal)
{
        if (sbi->s_commit_interval)
                journal->j_commit_interval = sbi->s_commit_interval;
        /* We could also set up an ext3-specific default for the commit
         * interval here, but for now we'll just fall back to the jbd
         * default. */
}


static journal_t *ext3_get_journal(struct super_block *sb, int journal_inum)
{
        struct inode *journal_inode;
        journal_t *journal;

        /* First, test for the existence of a valid inode on disk.  Bad
         * things happen if we iget() an unused inode, as the subsequent
         * iput() will try to delete it. */

        journal_inode = iget(sb, journal_inum);
        if (!journal_inode) {
                printk(KERN_ERR "EXT3-fs: no journal found.\n");
                return NULL;
        }
        if (!journal_inode->i_nlink) {
                make_bad_inode(journal_inode);
                iput(journal_inode);
                printk(KERN_ERR "EXT3-fs: journal inode is deleted.\n");
                return NULL;
        }

        jbd_debug(2, "Journal inode found at %p: %Ld bytes\n",
                  journal_inode, journal_inode->i_size);
        if (is_bad_inode(journal_inode) || !S_ISREG(journal_inode->i_mode)) {
                printk(KERN_ERR "EXT3-fs: invalid journal inode.\n");
                iput(journal_inode);
                return NULL;
        }

        journal = journal_init_inode(journal_inode);
        if (!journal) {
                printk(KERN_ERR "EXT3-fs: Could not load journal inode\n");
                iput(journal_inode);
        }
        ext3_init_journal_params(EXT3_SB(sb), journal);
        return journal;
}

static journal_t *ext3_get_dev_journal(struct super_block *sb,
                                       int dev)
{
        struct buffer_head * bh;
        journal_t *journal;
        int start;
        int len;
        int hblock, blocksize;
        unsigned long sb_block;
        unsigned long offset;
        kdev_t journal_dev = to_kdev_t(dev);
        struct ext3_super_block * es;
        struct block_device *bdev;

        bdev = ext3_blkdev_get(journal_dev);
        if (bdev == NULL)
                return NULL;

        blocksize = sb->s_blocksize;
        hblock = get_hardsect_size(journal_dev);
        if (blocksize < hblock) {
                printk(KERN_ERR
                        "EXT3-fs: blocksize too small for journal device.\n");
                goto out_bdev;
        }
        
        sb_block = EXT3_MIN_BLOCK_SIZE / blocksize;
        offset = EXT3_MIN_BLOCK_SIZE % blocksize;
        set_blocksize(dev, blocksize);
        if (!(bh = bread(dev, sb_block, blocksize))) {
                printk(KERN_ERR "EXT3-fs: couldn't read superblock of "
                       "external journal\n");
                goto out_bdev;
        }

        es = (struct ext3_super_block *) (((char *)bh->b_data) + offset);
        if ((le16_to_cpu(es->s_magic) != EXT3_SUPER_MAGIC) ||
            !(le32_to_cpu(es->s_feature_incompat) &
              EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
                printk(KERN_ERR "EXT3-fs: external journal has "
                                        "bad superblock\n");
                brelse(bh);
                goto out_bdev;
        }

        if (memcmp(EXT3_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
                printk(KERN_ERR "EXT3-fs: journal UUID does not match\n");
                brelse(bh);
                goto out_bdev;
        }

        len = le32_to_cpu(es->s_blocks_count);
        start = sb_block + 1;
        brelse(bh);     /* we're done with the superblock */

        journal = journal_init_dev(journal_dev, sb->s_dev, 
                                        start, len, blocksize);
        if (!journal) {
                printk(KERN_ERR "EXT3-fs: failed to create device journal\n");
                goto out_bdev;
        }
        ll_rw_block(READ, 1, &journal->j_sb_buffer);
        wait_on_buffer(journal->j_sb_buffer);
        if (!buffer_uptodate(journal->j_sb_buffer)) {
                printk(KERN_ERR "EXT3-fs: I/O error on journal device\n");
                goto out_journal;
        }
        if (ntohl(journal->j_superblock->s_nr_users) != 1) {
                printk(KERN_ERR "EXT3-fs: External journal has more than one "
                                        "user (unsupported) - %d\n",
                        ntohl(journal->j_superblock->s_nr_users));
                goto out_journal;
        }
        EXT3_SB(sb)->journal_bdev = bdev;
        ext3_init_journal_params(EXT3_SB(sb), journal);
        return journal;
out_journal:
        journal_destroy(journal);
out_bdev:
        ext3_blkdev_put(bdev);
        return NULL;
}

static int ext3_load_journal(struct super_block * sb,
                             struct ext3_super_block * es)
{
        journal_t *journal;
        int journal_inum = le32_to_cpu(es->s_journal_inum);
        int journal_dev = le32_to_cpu(es->s_journal_dev);
        int err = 0;
        int really_read_only;

        really_read_only = is_read_only(sb->s_dev);

        /*
         * Are we loading a blank journal or performing recovery after a
         * crash?  For recovery, we need to check in advance whether we
         * can get read-write access to the device.
         */

        if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER)) {
                if (sb->s_flags & MS_RDONLY) {
                        printk(KERN_INFO "EXT3-fs: INFO: recovery "
                                        "required on readonly filesystem.\n");
                        if (really_read_only) {
                                printk(KERN_ERR "EXT3-fs: write access "
                                        "unavailable, cannot proceed.\n");
                                return -EROFS;
                        }
                        printk (KERN_INFO "EXT3-fs: write access will "
                                        "be enabled during recovery.\n");
                }
        }

        if (journal_inum && journal_dev) {
                printk(KERN_ERR "EXT3-fs: filesystem has both journal "
                       "and inode journals!\n");
                return -EINVAL;
        }

        if (journal_inum) {
                if (!(journal = ext3_get_journal(sb, journal_inum)))
                        return -EINVAL;
        } else {
                if (!(journal = ext3_get_dev_journal(sb, journal_dev)))
                        return -EINVAL;
        }
        

        if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
                err = journal_update_format(journal);
                if (err)  {
                        printk(KERN_ERR "EXT3-fs: error updating journal.\n");
                        journal_destroy(journal);
                        return err;
                }
        }

        if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER))
                err = journal_wipe(journal, !really_read_only);
        if (!err)
                err = journal_load(journal);

        if (err) {
                printk(KERN_ERR "EXT3-fs: error loading journal.\n");
                journal_destroy(journal);
                return err;
        }

        EXT3_SB(sb)->s_journal = journal;
        ext3_clear_journal_err(sb, es);
        return 0;
}

static int ext3_create_journal(struct super_block * sb,
                               struct ext3_super_block * es,
                               int journal_inum)
{
        journal_t *journal;

        if (sb->s_flags & MS_RDONLY) {
                printk(KERN_ERR "EXT3-fs: readonly filesystem when trying to "
                                "create journal.\n");
                return -EROFS;
        }

        if (!(journal = ext3_get_journal(sb, journal_inum)))
                return -EINVAL;

        printk(KERN_INFO "EXT3-fs: creating new journal on inode %d\n",
               journal_inum);

        if (journal_create(journal)) {
                printk(KERN_ERR "EXT3-fs: error creating journal.\n");
                journal_destroy(journal);
                return -EIO;
        }

        EXT3_SB(sb)->s_journal = journal;

        ext3_update_dynamic_rev(sb);
        EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
        EXT3_SET_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL);

        es->s_journal_inum = cpu_to_le32(journal_inum);
        sb->s_dirt = 1;

        /* Make sure we flush the recovery flag to disk. */
        ext3_commit_super(sb, es, 1);

        return 0;
}

static void ext3_commit_super (struct super_block * sb,
                               struct ext3_super_block * es,
                               int sync)
{
        es->s_wtime = cpu_to_le32(CURRENT_TIME);
        BUFFER_TRACE(sb->u.ext3_sb.s_sbh, "marking dirty");
        mark_buffer_dirty(sb->u.ext3_sb.s_sbh);
        if (sync) {
                ll_rw_block(WRITE, 1, &sb->u.ext3_sb.s_sbh);
                wait_on_buffer(sb->u.ext3_sb.s_sbh);
        }
}


/*
 * Have we just finished recovery?  If so, and if we are mounting (or
 * remounting) the filesystem readonly, then we will end up with a
 * consistent fs on disk.  Record that fact.
 */
static void ext3_mark_recovery_complete(struct super_block * sb,
                                        struct ext3_super_block * es)
{
        journal_flush(EXT3_SB(sb)->s_journal);
        if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER) &&
            sb->s_flags & MS_RDONLY) {
                EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
                sb->s_dirt = 0;
                ext3_commit_super(sb, es, 1);
        }
}

/*
 * If we are mounting (or read-write remounting) a filesystem whose journal
 * has recorded an error from a previous lifetime, move that error to the
 * main filesystem now.
 */
static void ext3_clear_journal_err(struct super_block * sb,
                                   struct ext3_super_block * es)
{
        journal_t *journal;
        int j_errno;
        const char *errstr;
        
        journal = EXT3_SB(sb)->s_journal;

        /*
         * Now check for any error status which may have been recorded in the
         * journal by a prior ext3_error() or ext3_abort()
         */

        j_errno = journal_errno(journal);
        if (j_errno) {
                char nbuf[16];
                
                errstr = ext3_decode_error(sb, j_errno, nbuf);
                ext3_warning(sb, __FUNCTION__, "Filesystem error recorded "
                             "from previous mount: %s", errstr);
                ext3_warning(sb, __FUNCTION__, "Marking fs in need of "
                             "filesystem check.");
                
                sb->u.ext3_sb.s_mount_state |= EXT3_ERROR_FS;
                es->s_state |= cpu_to_le16(EXT3_ERROR_FS);
                ext3_commit_super (sb, es, 1);

                journal_clear_err(journal);
        }
}

/*
 * Force the running and committing transactions to commit,
 * and wait on the commit.
 */
int ext3_force_commit(struct super_block *sb)
{
        journal_t *journal;
        int ret;

        if (sb->s_flags & MS_RDONLY)
                return 0;

        journal = EXT3_SB(sb)->s_journal;
        sb->s_dirt = 0;
        lock_kernel();  /* important: lock down j_running_transaction */
        ret = ext3_journal_force_commit(journal);
        unlock_kernel();
        return ret;
}

/*
 * Ext3 always journals updates to the superblock itself, so we don't
 * have to propagate any other updates to the superblock on disk at this
 * point.  Just start an async writeback to get the buffers on their way
 * to the disk.
 *
 * This implicitly triggers the writebehind on sync().
 */

void ext3_write_super (struct super_block * sb)
{
        if (down_trylock(&sb->s_lock) == 0)
                BUG();
        sb->s_dirt = 0;
        log_start_commit(EXT3_SB(sb)->s_journal, NULL);
}

static int ext3_sync_fs(struct super_block *sb)
{
        tid_t target;
        
        sb->s_dirt = 0;
        target = log_start_commit(EXT3_SB(sb)->s_journal, NULL);
        log_wait_commit(EXT3_SB(sb)->s_journal, target);
        return 0;
}

/*
 * LVM calls this function before a (read-only) snapshot is created.  This
 * gives us a chance to flush the journal completely and mark the fs clean.
 */
void ext3_write_super_lockfs(struct super_block *sb)
{
        sb->s_dirt = 0;

        lock_kernel();          /* 2.4.5 forgot to do this for us */
        if (!(sb->s_flags & MS_RDONLY)) {
                journal_t *journal = EXT3_SB(sb)->s_journal;

                /* Now we set up the journal barrier. */
                unlock_super(sb);
                journal_lock_updates(journal);
                journal_flush(journal);
                lock_super(sb);

                /* Journal blocked and flushed, clear needs_recovery flag. */
                EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
                ext3_commit_super(sb, EXT3_SB(sb)->s_es, 1);
        }
        unlock_kernel();
}

/*
 * Called by LVM after the snapshot is done.  We need to reset the RECOVER
 * flag here, even though the filesystem is not technically dirty yet.
 */
void ext3_unlockfs(struct super_block *sb)
{
        if (!(sb->s_flags & MS_RDONLY)) {
                lock_kernel();
                lock_super(sb);
                /* Reser the needs_recovery flag before the fs is unlocked. */
                EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
                ext3_commit_super(sb, EXT3_SB(sb)->s_es, 1);
                unlock_super(sb);
                journal_unlock_updates(EXT3_SB(sb)->s_journal);
                unlock_kernel();
        }
}

int ext3_remount (struct super_block * sb, int * flags, char * data)
{
        struct ext3_super_block * es;
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        unsigned long tmp;

        clear_ro_after(sb);

        /*
         * Allow the "check" option to be passed as a remount option.
         */
        if (!parse_options(data, &tmp, sbi, &tmp, 1))
                return -EINVAL;

        if (sbi->s_mount_opt & EXT3_MOUNT_ABORT)
                ext3_abort(sb, __FUNCTION__, "Abort forced by user");

        es = sbi->s_es;

        ext3_init_journal_params(sbi, sbi->s_journal);
        
        if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
                if (sbi->s_mount_opt & EXT3_MOUNT_ABORT)
                        return -EROFS;

                if (*flags & MS_RDONLY) {
                        /*
                         * First of all, the unconditional stuff we have to do
                         * to disable replay of the journal when we next remount
                         */
                        sb->s_flags |= MS_RDONLY;

                        /*
                         * OK, test if we are remounting a valid rw partition
                         * readonly, and if so set the rdonly flag and then
                         * mark the partition as valid again.
                         */
                        if (!(es->s_state & cpu_to_le16(EXT3_VALID_FS)) &&
                            (sbi->s_mount_state & EXT3_VALID_FS))
                                es->s_state = cpu_to_le16(sbi->s_mount_state);

                        ext3_mark_recovery_complete(sb, es);
                } else {
                        int ret;
                        if ((ret = EXT3_HAS_RO_COMPAT_FEATURE(sb,
                                        ~EXT3_FEATURE_RO_COMPAT_SUPP))) {
                                printk(KERN_WARNING "EXT3-fs: %s: couldn't "
                                       "remount RDWR because of unsupported "
                                       "optional features (%x).\n",
                                       bdevname(sb->s_dev), ret);
                                return -EROFS;
                        }
                        /*
                         * Mounting a RDONLY partition read-write, so reread
                         * and store the current valid flag.  (It may have
                         * been changed by e2fsck since we originally mounted
                         * the partition.)
                         */
                        ext3_clear_journal_err(sb, es);
                        sbi->s_mount_state = le16_to_cpu(es->s_state);
                        if (!ext3_setup_super (sb, es, 0))
                                sb->s_flags &= ~MS_RDONLY;
                }
        }
        setup_ro_after(sb);
        return 0;
}

int ext3_statfs (struct super_block * sb, struct statfs * buf)
{
        struct ext3_super_block *es = EXT3_SB(sb)->s_es;
        unsigned long overhead;
        int i;

        if (test_opt (sb, MINIX_DF))
                overhead = 0;
        else {
                /*
                 * Compute the overhead (FS structures)
                 */

                /*
                 * All of the blocks before first_data_block are
                 * overhead
                 */
                overhead = le32_to_cpu(es->s_first_data_block);

                /*
                 * Add the overhead attributed to the superblock and
                 * block group descriptors.  If the sparse superblocks
                 * feature is turned on, then not all groups have this.
                 */
                for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++)
                        overhead += ext3_bg_has_super(sb, i) +
                                ext3_bg_num_gdb(sb, i);

                /*
                 * Every block group has an inode bitmap, a block
                 * bitmap, and an inode table.
                 */
                overhead += (EXT3_SB(sb)->s_groups_count *
                             (2 + EXT3_SB(sb)->s_itb_per_group));
        }

        buf->f_type = EXT3_SUPER_MAGIC;
        buf->f_bsize = sb->s_blocksize;
        buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
        buf->f_bfree = ext3_count_free_blocks (sb);
        buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
        if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
                buf->f_bavail = 0;
        buf->f_files = le32_to_cpu(es->s_inodes_count);
        buf->f_ffree = ext3_count_free_inodes (sb);
        buf->f_namelen = EXT3_NAME_LEN;
        return 0;
}

static DECLARE_FSTYPE_DEV(ext3_fs_type, "ext3", ext3_read_super);

static int __init init_ext3_fs(void)
{
        return register_filesystem(&ext3_fs_type);
}

static void __exit exit_ext3_fs(void)
{
        unregister_filesystem(&ext3_fs_type);
}

EXPORT_NO_SYMBOLS;

MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
MODULE_DESCRIPTION("Second Extended Filesystem with journaling extensions");
MODULE_LICENSE("GPL");
module_init(init_ext3_fs)
module_exit(exit_ext3_fs)