[PATCH] fix race in __block_prepare_write

[linux-2.6] / 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/time.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/blkdev.h>
#include <linux/parser.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>
#include <linux/random.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/quotaops.h>
#include <asm/uaccess.h>
#include "xattr.h"
#include "acl.h"

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, int wait);
static const char *ext3_decode_error(struct super_block * sb, int errno,
                                     char nbuf[16]);
static int ext3_remount (struct super_block * sb, int * flags, char * data);
static int ext3_statfs (struct super_block * sb, struct kstatfs * buf);
static void ext3_unlockfs(struct super_block *sb);
static void ext3_write_super (struct super_block * sb);
static void ext3_write_super_lockfs(struct super_block *sb);

/* 
 * Wrappers for journal_start/end.
 *
 * The only special thing we need to do here is to make sure that all
 * journal_end calls result in the superblock being marked dirty, so
 * that sync() will call the filesystem's write_super callback if
 * appropriate. 
 */
handle_t *ext3_journal_start_sb(struct super_block *sb, int nblocks)
{
        journal_t *journal;

        if (sb->s_flags & MS_RDONLY)
                return ERR_PTR(-EROFS);

        /* Special case here: if the journal has aborted behind our
         * backs (eg. EIO in the commit thread), then we still need to
         * take the FS itself readonly cleanly. */
        journal = EXT3_SB(sb)->s_journal;
        if (is_journal_aborted(journal)) {
                ext3_abort(sb, __FUNCTION__,
                           "Detected aborted journal");
                return ERR_PTR(-EROFS);
        }

        return journal_start(journal, nblocks);
}

/* 
 * The only special thing we need to do here is to make sure that all
 * journal_stop calls result in the superblock being marked dirty, so
 * that sync() will call the filesystem's write_super callback if
 * appropriate. 
 */
int __ext3_journal_stop(const char *where, handle_t *handle)
{
        struct super_block *sb;
        int err;
        int rc;

        sb = handle->h_transaction->t_journal->j_private;
        err = handle->h_err;
        rc = journal_stop(handle);

        if (!err)
                err = rc;
        if (err)
                __ext3_std_error(sb, where, err);
        return err;
}

void ext3_journal_abort_handle(const char *caller, const char *err_fn,
                struct buffer_head *bh, handle_t *handle, int err)
{
        char nbuf[16];
        const char *errstr = ext3_decode_error(NULL, err, nbuf);

        if (bh)
                BUFFER_TRACE(bh, "abort");

        if (!handle->h_err)
                handle->h_err = err;

        if (is_handle_aborted(handle))
                return;

        printk(KERN_ERR "%s: aborting transaction: %s in %s\n",
               caller, errstr, err_fn);

        journal_abort_handle(handle);
}

/* 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_le16(EXT3_ERROR_FS);

        if (sb->s_flags & MS_RDONLY)
                return;

        if (test_opt (sb, ERRORS_RO)) {
                printk (KERN_CRIT "Remounting filesystem read-only\n");
                sb->s_flags |= MS_RDONLY;
        } else {
                journal_t *journal = EXT3_SB(sb)->s_journal;

                EXT3_SB(sb)->s_mount_opt |= EXT3_MOUNT_ABORT;
                if (journal)
                        journal_abort(journal, -EIO);
        }
        if (test_opt(sb, ERRORS_PANIC))
                panic("EXT3-fs (device %s): panic forced after error\n",
                        sb->s_id);
        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);
        printk(KERN_CRIT "EXT3-fs error (device %s): %s: ",sb->s_id, function);
        vprintk(fmt, args);
        printk("\n");
        va_end(args);

        ext3_handle_error(sb);
}

static 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",
                sb->s_id, 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);
        printk(KERN_CRIT "EXT3-fs error (device %s): %s: ",sb->s_id, function);
        vprintk(fmt, args);
        printk("\n");
        va_end(args);

        if (test_opt(sb, ERRORS_PANIC))
                panic("EXT3-fs panic from previous error\n");

        if (sb->s_flags & MS_RDONLY)
                return;

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

void ext3_warning (struct super_block * sb, const char * function,
                   const char * fmt, ...)
{
        va_list args;

        va_start(args, fmt);
        printk(KERN_WARNING "EXT3-fs warning (device %s): %s: ",
               sb->s_id, function);
        vprintk(fmt, args);
        printk("\n");
        va_end(args);
}

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(dev_t dev)
{
        struct block_device *bdev;
        char b[BDEVNAME_SIZE];

        bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
        if (IS_ERR(bdev))
                goto fail;
        return bdev;

fail:
        printk(KERN_ERR "EXT3: failed to open journal device %s: %ld\n",
                        __bdevname(dev, b), PTR_ERR(bdev));
        return NULL;
}

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

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 = NULL;
        }
        return ret;
}

static inline struct inode *orphan_list_entry(struct list_head *l)
{
        return &list_entry(l, struct ext3_inode_info, i_orphan)->vfs_inode;
}

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 %s:%ld at %p: mode %o, nlink %d, next %d\n",
                       inode->i_sb->s_id, inode->i_ino, inode,
                       inode->i_mode, inode->i_nlink, 
                       NEXT_ORPHAN(inode));
        }
}

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

        ext3_xattr_put_super(sb);
        journal_destroy(sbi->s_journal);
        if (!(sb->s_flags & MS_RDONLY)) {
                EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
                es->s_state = cpu_to_le16(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);
        percpu_counter_destroy(&sbi->s_freeblocks_counter);
        percpu_counter_destroy(&sbi->s_freeinodes_counter);
        percpu_counter_destroy(&sbi->s_dirs_counter);
        brelse(sbi->s_sbh);
#ifdef CONFIG_QUOTA
        for (i = 0; i < MAXQUOTAS; i++)
                kfree(sbi->s_qf_names[i]);
#endif

        /* 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_bdev(sb->s_bdev, 0);
        if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
                /*
                 * 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.
                 */
                sync_blockdev(sbi->journal_bdev);
                invalidate_bdev(sbi->journal_bdev, 0);
                ext3_blkdev_remove(sbi);
        }
        sb->s_fs_info = NULL;
        kfree(sbi);
        return;
}

static kmem_cache_t *ext3_inode_cachep;

/*
 * Called inside transaction, so use GFP_NOFS
 */
static struct inode *ext3_alloc_inode(struct super_block *sb)
{
        struct ext3_inode_info *ei;

        ei = kmem_cache_alloc(ext3_inode_cachep, SLAB_NOFS);
        if (!ei)
                return NULL;
#ifdef CONFIG_EXT3_FS_POSIX_ACL
        ei->i_acl = EXT3_ACL_NOT_CACHED;
        ei->i_default_acl = EXT3_ACL_NOT_CACHED;
#endif
        ei->i_block_alloc_info = NULL;
        ei->vfs_inode.i_version = 1;
        return &ei->vfs_inode;
}

static void ext3_destroy_inode(struct inode *inode)
{
        kmem_cache_free(ext3_inode_cachep, EXT3_I(inode));
}

static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
        struct ext3_inode_info *ei = (struct ext3_inode_info *) foo;

        if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
            SLAB_CTOR_CONSTRUCTOR) {
                INIT_LIST_HEAD(&ei->i_orphan);
#ifdef CONFIG_EXT3_FS_XATTR
                init_rwsem(&ei->xattr_sem);
#endif
                init_MUTEX(&ei->truncate_sem);
                inode_init_once(&ei->vfs_inode);
        }
}
 
static int init_inodecache(void)
{
        ext3_inode_cachep = kmem_cache_create("ext3_inode_cache",
                                             sizeof(struct ext3_inode_info),
                                             0, SLAB_RECLAIM_ACCOUNT,
                                             init_once, NULL);
        if (ext3_inode_cachep == NULL)
                return -ENOMEM;
        return 0;
}

static void destroy_inodecache(void)
{
        if (kmem_cache_destroy(ext3_inode_cachep))
                printk(KERN_INFO "ext3_inode_cache: not all structures were freed\n");
}

static void ext3_clear_inode(struct inode *inode)
{
        struct ext3_block_alloc_info *rsv = EXT3_I(inode)->i_block_alloc_info;
#ifdef CONFIG_EXT3_FS_POSIX_ACL
       if (EXT3_I(inode)->i_acl &&
           EXT3_I(inode)->i_acl != EXT3_ACL_NOT_CACHED) {
               posix_acl_release(EXT3_I(inode)->i_acl);
               EXT3_I(inode)->i_acl = EXT3_ACL_NOT_CACHED;
       }
       if (EXT3_I(inode)->i_default_acl &&
           EXT3_I(inode)->i_default_acl != EXT3_ACL_NOT_CACHED) {
               posix_acl_release(EXT3_I(inode)->i_default_acl);
               EXT3_I(inode)->i_default_acl = EXT3_ACL_NOT_CACHED;
       }
#endif
        ext3_discard_reservation(inode);
        EXT3_I(inode)->i_block_alloc_info = NULL;
        kfree(rsv);
}

#ifdef CONFIG_QUOTA

#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))

static int ext3_dquot_initialize(struct inode *inode, int type);
static int ext3_dquot_drop(struct inode *inode);
static int ext3_write_dquot(struct dquot *dquot);
static int ext3_acquire_dquot(struct dquot *dquot);
static int ext3_release_dquot(struct dquot *dquot);
static int ext3_mark_dquot_dirty(struct dquot *dquot);
static int ext3_write_info(struct super_block *sb, int type);
static int ext3_quota_on(struct super_block *sb, int type, int format_id, char *path);
static int ext3_quota_on_mount(struct super_block *sb, int type);
static ssize_t ext3_quota_read(struct super_block *sb, int type, char *data,
                               size_t len, loff_t off);
static ssize_t ext3_quota_write(struct super_block *sb, int type,
                                const char *data, size_t len, loff_t off);

static struct dquot_operations ext3_quota_operations = {
        .initialize     = ext3_dquot_initialize,
        .drop           = ext3_dquot_drop,
        .alloc_space    = dquot_alloc_space,
        .alloc_inode    = dquot_alloc_inode,
        .free_space     = dquot_free_space,
        .free_inode     = dquot_free_inode,
        .transfer       = dquot_transfer,
        .write_dquot    = ext3_write_dquot,
        .acquire_dquot  = ext3_acquire_dquot,
        .release_dquot  = ext3_release_dquot,
        .mark_dirty     = ext3_mark_dquot_dirty,
        .write_info     = ext3_write_info
};

static struct quotactl_ops ext3_qctl_operations = {
        .quota_on       = ext3_quota_on,
        .quota_off      = vfs_quota_off,
        .quota_sync     = vfs_quota_sync,
        .get_info       = vfs_get_dqinfo,
        .set_info       = vfs_set_dqinfo,
        .get_dqblk      = vfs_get_dqblk,
        .set_dqblk      = vfs_set_dqblk
};
#endif

static struct super_operations ext3_sops = {
        .alloc_inode    = ext3_alloc_inode,
        .destroy_inode  = ext3_destroy_inode,
        .read_inode     = ext3_read_inode,
        .write_inode    = ext3_write_inode,
        .dirty_inode    = ext3_dirty_inode,
        .delete_inode   = ext3_delete_inode,
        .put_super      = ext3_put_super,
        .write_super    = ext3_write_super,
        .sync_fs        = ext3_sync_fs,
        .write_super_lockfs = ext3_write_super_lockfs,
        .unlockfs       = ext3_unlockfs,
        .statfs         = ext3_statfs,
        .remount_fs     = ext3_remount,
        .clear_inode    = ext3_clear_inode,
#ifdef CONFIG_QUOTA
        .quota_read     = ext3_quota_read,
        .quota_write    = ext3_quota_write,
#endif
};

struct dentry *ext3_get_parent(struct dentry *child);
static struct export_operations ext3_export_ops = {
        .get_parent = ext3_get_parent,
};

enum {
        Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
        Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
        Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov,
        Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
        Opt_reservation, Opt_noreservation, Opt_noload, Opt_nobh,
        Opt_commit, Opt_journal_update, Opt_journal_inum,
        Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
        Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
        Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0,
        Opt_ignore, Opt_barrier, Opt_err, Opt_resize,
};

static match_table_t tokens = {
        {Opt_bsd_df, "bsddf"},
        {Opt_minix_df, "minixdf"},
        {Opt_grpid, "grpid"},
        {Opt_grpid, "bsdgroups"},
        {Opt_nogrpid, "nogrpid"},
        {Opt_nogrpid, "sysvgroups"},
        {Opt_resgid, "resgid=%u"},
        {Opt_resuid, "resuid=%u"},
        {Opt_sb, "sb=%u"},
        {Opt_err_cont, "errors=continue"},
        {Opt_err_panic, "errors=panic"},
        {Opt_err_ro, "errors=remount-ro"},
        {Opt_nouid32, "nouid32"},
        {Opt_nocheck, "nocheck"},
        {Opt_nocheck, "check=none"},
        {Opt_check, "check"},
        {Opt_debug, "debug"},
        {Opt_oldalloc, "oldalloc"},
        {Opt_orlov, "orlov"},
        {Opt_user_xattr, "user_xattr"},
        {Opt_nouser_xattr, "nouser_xattr"},
        {Opt_acl, "acl"},
        {Opt_noacl, "noacl"},
        {Opt_reservation, "reservation"},
        {Opt_noreservation, "noreservation"},
        {Opt_noload, "noload"},
        {Opt_nobh, "nobh"},
        {Opt_commit, "commit=%u"},
        {Opt_journal_update, "journal=update"},
        {Opt_journal_inum, "journal=%u"},
        {Opt_abort, "abort"},
        {Opt_data_journal, "data=journal"},
        {Opt_data_ordered, "data=ordered"},
        {Opt_data_writeback, "data=writeback"},
        {Opt_offusrjquota, "usrjquota="},
        {Opt_usrjquota, "usrjquota=%s"},
        {Opt_offgrpjquota, "grpjquota="},
        {Opt_grpjquota, "grpjquota=%s"},
        {Opt_jqfmt_vfsold, "jqfmt=vfsold"},
        {Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
        {Opt_ignore, "grpquota"},
        {Opt_ignore, "noquota"},
        {Opt_ignore, "quota"},
        {Opt_ignore, "usrquota"},
        {Opt_barrier, "barrier=%u"},
        {Opt_err, NULL},
        {Opt_resize, "resize"},
};

static unsigned long get_sb_block(void **data)
{
        unsigned long   sb_block;
        char            *options = (char *) *data;

        if (!options || strncmp(options, "sb=", 3) != 0)
                return 1;       /* Default location */
        options += 3;
        sb_block = simple_strtoul(options, &options, 0);
        if (*options && *options != ',') {
                printk("EXT3-fs: Invalid sb specification: %s\n",
                       (char *) *data);
                return 1;
        }
        if (*options == ',')
                options++;
        *data = (void *) options;
        return sb_block;
}

static int parse_options (char * options, struct super_block *sb,
                          unsigned long * inum, unsigned long *n_blocks_count, int is_remount)
{
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        char * p;
        substring_t args[MAX_OPT_ARGS];
        int data_opt = 0;
        int option;
#ifdef CONFIG_QUOTA
        int qtype;
        char *qname;
#endif

        if (!options)
                return 1;

        while ((p = strsep (&options, ",")) != NULL) {
                int token;
                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_bsd_df:
                        clear_opt (sbi->s_mount_opt, MINIX_DF);
                        break;
                case Opt_minix_df:
                        set_opt (sbi->s_mount_opt, MINIX_DF);
                        break;
                case Opt_grpid:
                        set_opt (sbi->s_mount_opt, GRPID);
                        break;
                case Opt_nogrpid:
                        clear_opt (sbi->s_mount_opt, GRPID);
                        break;
                case Opt_resuid:
                        if (match_int(&args[0], &option))
                                return 0;
                        sbi->s_resuid = option;
                        break;
                case Opt_resgid:
                        if (match_int(&args[0], &option))
                                return 0;
                        sbi->s_resgid = option;
                        break;
                case Opt_sb:
                        /* handled by get_sb_block() instead of here */
                        /* *sb_block = match_int(&args[0]); */
                        break;
                case Opt_err_panic:
                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
                        set_opt (sbi->s_mount_opt, ERRORS_PANIC);
                        break;
                case Opt_err_ro:
                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
                        set_opt (sbi->s_mount_opt, ERRORS_RO);
                        break;
                case Opt_err_cont:
                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
                        set_opt (sbi->s_mount_opt, ERRORS_CONT);
                        break;
                case Opt_nouid32:
                        set_opt (sbi->s_mount_opt, NO_UID32);
                        break;
                case Opt_check:
#ifdef CONFIG_EXT3_CHECK
                        set_opt (sbi->s_mount_opt, CHECK);
#else
                        printk(KERN_ERR
                               "EXT3 Check option not supported\n");
#endif
                        break;
                case Opt_nocheck:
                        clear_opt (sbi->s_mount_opt, CHECK);
                        break;
                case Opt_debug:
                        set_opt (sbi->s_mount_opt, DEBUG);
                        break;
                case Opt_oldalloc:
                        set_opt (sbi->s_mount_opt, OLDALLOC);
                        break;
                case Opt_orlov:
                        clear_opt (sbi->s_mount_opt, OLDALLOC);
                        break;
#ifdef CONFIG_EXT3_FS_XATTR
                case Opt_user_xattr:
                        set_opt (sbi->s_mount_opt, XATTR_USER);
                        break;
                case Opt_nouser_xattr:
                        clear_opt (sbi->s_mount_opt, XATTR_USER);
                        break;
#else
                case Opt_user_xattr:
                case Opt_nouser_xattr:
                        printk("EXT3 (no)user_xattr options not supported\n");
                        break;
#endif
#ifdef CONFIG_EXT3_FS_POSIX_ACL
                case Opt_acl:
                        set_opt(sbi->s_mount_opt, POSIX_ACL);
                        break;
                case Opt_noacl:
                        clear_opt(sbi->s_mount_opt, POSIX_ACL);
                        break;
#else
                case Opt_acl:
                case Opt_noacl:
                        printk("EXT3 (no)acl options not supported\n");
                        break;
#endif
                case Opt_reservation:
                        set_opt(sbi->s_mount_opt, RESERVATION);
                        break;
                case Opt_noreservation:
                        clear_opt(sbi->s_mount_opt, RESERVATION);
                        break;
                case Opt_journal_update:
                        /* @@@ 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;
                        }
                        set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
                        break;
                case Opt_journal_inum:
                        if (is_remount) {
                                printk(KERN_ERR "EXT3-fs: cannot specify "
                                       "journal on remount\n");
                                return 0;
                        }
                        if (match_int(&args[0], &option))
                                return 0;
                        *inum = option;
                        break;
                case Opt_noload:
                        set_opt (sbi->s_mount_opt, NOLOAD);
                        break;
                case Opt_commit:
                        if (match_int(&args[0], &option))
                                return 0;
                        if (option < 0)
                                return 0;
                        if (option == 0)
                                option = JBD_DEFAULT_MAX_COMMIT_AGE;
                        sbi->s_commit_interval = HZ * option;
                        break;
                case Opt_data_journal:
                        data_opt = EXT3_MOUNT_JOURNAL_DATA;
                        goto datacheck;
                case Opt_data_ordered:
                        data_opt = EXT3_MOUNT_ORDERED_DATA;
                        goto datacheck;
                case Opt_data_writeback:
                        data_opt = EXT3_MOUNT_WRITEBACK_DATA;
                datacheck:
                        if (is_remount) {
                                if ((sbi->s_mount_opt & EXT3_MOUNT_DATA_FLAGS)
                                                != data_opt) {
                                        printk(KERN_ERR
                                                "EXT3-fs: cannot change data "
                                                "mode on remount\n");
                                        return 0;
                                }
                        } else {
                                sbi->s_mount_opt &= ~EXT3_MOUNT_DATA_FLAGS;
                                sbi->s_mount_opt |= data_opt;
                        }
                        break;
#ifdef CONFIG_QUOTA
                case Opt_usrjquota:
                        qtype = USRQUOTA;
                        goto set_qf_name;
                case Opt_grpjquota:
                        qtype = GRPQUOTA;
set_qf_name:
                        if (sb_any_quota_enabled(sb)) {
                                printk(KERN_ERR
                                        "EXT3-fs: Cannot change journalled "
                                        "quota options when quota turned on.\n");
                                return 0;
                        }
                        qname = match_strdup(&args[0]);
                        if (!qname) {
                                printk(KERN_ERR
                                        "EXT3-fs: not enough memory for "
                                        "storing quotafile name.\n");
                                return 0;
                        }
                        if (sbi->s_qf_names[qtype] &&
                            strcmp(sbi->s_qf_names[qtype], qname)) {
                                printk(KERN_ERR
                                        "EXT3-fs: %s quota file already "
                                        "specified.\n", QTYPE2NAME(qtype));
                                kfree(qname);
                                return 0;
                        }
                        sbi->s_qf_names[qtype] = qname;
                        if (strchr(sbi->s_qf_names[qtype], '/')) {
                                printk(KERN_ERR
                                        "EXT3-fs: quotafile must be on "
                                        "filesystem root.\n");
                                kfree(sbi->s_qf_names[qtype]);
                                sbi->s_qf_names[qtype] = NULL;
                                return 0;
                        }
                        break;
                case Opt_offusrjquota:
                        qtype = USRQUOTA;
                        goto clear_qf_name;
                case Opt_offgrpjquota:
                        qtype = GRPQUOTA;
clear_qf_name:
                        if (sb_any_quota_enabled(sb)) {
                                printk(KERN_ERR "EXT3-fs: Cannot change "
                                        "journalled quota options when "
                                        "quota turned on.\n");
                                return 0;
                        }
                        kfree(sbi->s_qf_names[qtype]);
                        sbi->s_qf_names[qtype] = NULL;
                        break;
                case Opt_jqfmt_vfsold:
                        sbi->s_jquota_fmt = QFMT_VFS_OLD;
                        break;
                case Opt_jqfmt_vfsv0:
                        sbi->s_jquota_fmt = QFMT_VFS_V0;
                        break;
#else
                case Opt_usrjquota:
                case Opt_grpjquota:
                case Opt_offusrjquota:
                case Opt_offgrpjquota:
                case Opt_jqfmt_vfsold:
                case Opt_jqfmt_vfsv0:
                        printk(KERN_ERR
                                "EXT3-fs: journalled quota options not "
                                "supported.\n");
                        break;
#endif
                case Opt_abort:
                        set_opt(sbi->s_mount_opt, ABORT);
                        break;
                case Opt_barrier:
                        if (match_int(&args[0], &option))
                                return 0;
                        if (option)
                                set_opt(sbi->s_mount_opt, BARRIER);
                        else
                                clear_opt(sbi->s_mount_opt, BARRIER);
                        break;
                case Opt_ignore:
                        break;
                case Opt_resize:
                        if (!n_blocks_count) {
                                printk("EXT3-fs: resize option only available "
                                        "for remount\n");
                                return 0;
                        }
                        match_int(&args[0], &option);
                        *n_blocks_count = option;
                        break;
                case Opt_nobh:
                        set_opt(sbi->s_mount_opt, NOBH);
                        break;
                default:
                        printk (KERN_ERR
                                "EXT3-fs: Unrecognized mount option \"%s\" "
                                "or missing value\n", p);
                        return 0;
                }
        }
#ifdef CONFIG_QUOTA
        if (!sbi->s_jquota_fmt && (sbi->s_qf_names[USRQUOTA] ||
            sbi->s_qf_names[GRPQUOTA])) {
                printk(KERN_ERR
                        "EXT3-fs: journalled quota format not specified.\n");
                return 0;
        }
#endif

        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) <= get_seconds()))
                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 = 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(get_seconds());
        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 bs=%lu, gc=%lu, "
                                "bpg=%lu, ipg=%lu, mo=%04lx]\n",
                        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 on %s, ", sb->s_id);
        if (EXT3_SB(sb)->s_journal->j_inode == NULL) {
                char b[BDEVNAME_SIZE];

                printk("external journal on %s\n",
                        bdevname(EXT3_SB(sb)->s_journal->j_dev, b));
        } 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
        return res;
}

/* Called at mount-time, super-block is locked */
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++;
        }

        sbi->s_es->s_free_blocks_count=cpu_to_le32(ext3_count_free_blocks(sb));
        sbi->s_es->s_free_inodes_count=cpu_to_le32(ext3_count_free_inodes(sb));
        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;
#ifdef CONFIG_QUOTA
        int i;
#endif
        if (!es->s_last_orphan) {
                jbd_debug(4, "no orphan inodes to clean up\n");
                return;
        }

        if (EXT3_SB(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;
        }

        if (s_flags & MS_RDONLY) {
                printk(KERN_INFO "EXT3-fs: %s: orphan cleanup on readonly fs\n",
                       sb->s_id);
                sb->s_flags &= ~MS_RDONLY;
        }
#ifdef CONFIG_QUOTA
        /* Needed for iput() to work correctly and not trash data */
        sb->s_flags |= MS_ACTIVE;
        /* Turn on quotas so that they are updated correctly */
        for (i = 0; i < MAXQUOTAS; i++) {
                if (EXT3_SB(sb)->s_qf_names[i]) {
                        int ret = ext3_quota_on_mount(sb, i);
                        if (ret < 0)
                                printk(KERN_ERR
                                        "EXT3-fs: Cannot turn on journalled "
                                        "quota: error %d\n", ret);
                }
        }
#endif

        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);
                DQUOT_INIT(inode);
                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",
                       sb->s_id, PLURAL(nr_orphans));
        if (nr_truncates)
                printk(KERN_INFO "EXT3-fs: %s: %d truncate%s cleaned up\n",
                       sb->s_id, PLURAL(nr_truncates));
#ifdef CONFIG_QUOTA
        /* Turn quotas off */
        for (i = 0; i < MAXQUOTAS; i++) {
                if (sb_dqopt(sb)->files[i])
                        vfs_quota_off(sb, i);
        }
#endif
        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;
        /* This constant is calculated to be the largest file size for a
         * dense, 4k-blocksize file such that the total number of
         * sectors in the file, including data and all indirect blocks,
         * does not exceed 2^32. */
        const loff_t upper_limit = 0x1ff7fffd000LL;

        res += 1LL << (bits-2);
        res += 1LL << (2*(bits-2));
        res += 1LL << (3*(bits-2));
        res <<= bits;
        if (res > upper_limit)
                res = upper_limit;
        return res;
}

static unsigned long descriptor_loc(struct super_block *sb,
                                    unsigned long logic_sb_block,
                                    int nr)
{
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        unsigned long bg, first_data_block, first_meta_bg;
        int has_super = 0;

        first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
        first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);

        if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_META_BG) ||
            nr < first_meta_bg)
                return (logic_sb_block + nr + 1);
        bg = sbi->s_desc_per_block * nr;
        if (ext3_bg_has_super(sb, bg))
                has_super = 1;
        return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
}


static int ext3_fill_super (struct super_block *sb, void *data, int silent)
{
        struct buffer_head * bh;
        struct ext3_super_block *es = NULL;
        struct ext3_sb_info *sbi;
        unsigned long block;
        unsigned long sb_block = get_sb_block(&data);
        unsigned long logic_sb_block;
        unsigned long offset = 0;
        unsigned long journal_inum = 0;
        unsigned long def_mount_opts;
        struct inode *root;
        int blocksize;
        int hblock;
        int db_count;
        int i;
        int needs_recovery;
        __le32 features;

        sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
        if (!sbi)
                return -ENOMEM;
        sb->s_fs_info = sbi;
        memset(sbi, 0, sizeof(*sbi));
        sbi->s_mount_opt = 0;
        sbi->s_resuid = EXT3_DEF_RESUID;
        sbi->s_resgid = EXT3_DEF_RESGID;

        unlock_kernel();

        blocksize = sb_min_blocksize(sb, EXT3_MIN_BLOCK_SIZE);
        if (!blocksize) {
                printk(KERN_ERR "EXT3-fs: unable to set blocksize\n");
                goto out_fail;
        }

        /*
         * 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;
        } else {
                logic_sb_block = sb_block;
        }

        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)
                goto cantfind_ext3;

        /* Set defaults before we parse the mount options */
        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
        if (def_mount_opts & EXT3_DEFM_DEBUG)
                set_opt(sbi->s_mount_opt, DEBUG);
        if (def_mount_opts & EXT3_DEFM_BSDGROUPS)
                set_opt(sbi->s_mount_opt, GRPID);
        if (def_mount_opts & EXT3_DEFM_UID16)
                set_opt(sbi->s_mount_opt, NO_UID32);
        if (def_mount_opts & EXT3_DEFM_XATTR_USER)
                set_opt(sbi->s_mount_opt, XATTR_USER);
        if (def_mount_opts & EXT3_DEFM_ACL)
                set_opt(sbi->s_mount_opt, POSIX_ACL);
        if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_DATA)
                sbi->s_mount_opt |= EXT3_MOUNT_JOURNAL_DATA;
        else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_ORDERED)
                sbi->s_mount_opt |= EXT3_MOUNT_ORDERED_DATA;
        else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_WBACK)
                sbi->s_mount_opt |= EXT3_MOUNT_WRITEBACK_DATA;

        if (le16_to_cpu(sbi->s_es->s_errors) == EXT3_ERRORS_PANIC)
                set_opt(sbi->s_mount_opt, ERRORS_PANIC);
        else if (le16_to_cpu(sbi->s_es->s_errors) == EXT3_ERRORS_RO)
                set_opt(sbi->s_mount_opt, ERRORS_RO);

        sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
        sbi->s_resgid = le16_to_cpu(es->s_def_resgid);

        set_opt(sbi->s_mount_opt, RESERVATION);

        if (!parse_options ((char *) data, sb, &journal_inum, NULL, 0))
                goto failed_mount;

        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
                ((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);

        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.
         */
        features = EXT3_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP);
        if (features) {
                printk(KERN_ERR "EXT3-fs: %s: couldn't mount because of "
                       "unsupported optional features (%x).\n",
                       sb->s_id, le32_to_cpu(features));
                goto failed_mount;
        }
        features = EXT3_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP);
        if (!(sb->s_flags & MS_RDONLY) && features) {
                printk(KERN_ERR "EXT3-fs: %s: couldn't mount RDWR because of "
                       "unsupported optional features (%x).\n",
                       sb->s_id, le32_to_cpu(features));
                goto failed_mount;
        }
        blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);

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

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

                brelse (bh);
                sb_set_blocksize(sb, 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");
                        goto failed_mount;
                }
                es = (struct ext3_super_block *)(((char *)bh->b_data) + offset);
                sbi->s_es = es;
                if (es->s_magic != cpu_to_le16(EXT3_SUPER_MAGIC)) {
                        printk (KERN_ERR 
                                "EXT3-fs: Magic mismatch, very weird !\n");
                        goto failed_mount;
                }
        }

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

        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) ||
                    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
                    (sbi->s_inode_size > blocksize)) {
                        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);
        if (EXT3_INODE_SIZE(sb) == 0)
                goto cantfind_ext3;
        sbi->s_inodes_per_block = blocksize / EXT3_INODE_SIZE(sb);
        if (sbi->s_inodes_per_block == 0)
                goto cantfind_ext3;
        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;
        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));
        for (i=0; i < 4; i++)
                sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
        sbi->s_def_hash_version = es->s_def_hash_version;

        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;
        }

        if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
                goto cantfind_ext3;
        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;
        }

        percpu_counter_init(&sbi->s_freeblocks_counter);
        percpu_counter_init(&sbi->s_freeinodes_counter);
        percpu_counter_init(&sbi->s_dirs_counter);
        bgl_lock_init(&sbi->s_blockgroup_lock);

        for (i = 0; i < db_count; i++) {
                block = descriptor_loc(sb, logic_sb_block, i);
                sbi->s_group_desc[i] = sb_bread(sb, block);
                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;
        }
        sbi->s_gdb_count = db_count;
        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
        spin_lock_init(&sbi->s_next_gen_lock);
        /* per fileystem reservation list head & lock */
        spin_lock_init(&sbi->s_rsv_window_lock);
        sbi->s_rsv_window_root = RB_ROOT;
        /* Add a single, static dummy reservation to the start of the
         * reservation window list --- it gives us a placeholder for
         * append-at-start-of-list which makes the allocation logic
         * _much_ simpler. */
        sbi->s_rsv_window_head.rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
        sbi->s_rsv_window_head.rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
        sbi->s_rsv_window_head.rsv_alloc_hit = 0;
        sbi->s_rsv_window_head.rsv_goal_size = 0;
        ext3_rsv_window_add(sb, &sbi->s_rsv_window_head);

        /*
         * set up enough so that it can read an inode
         */
        sb->s_op = &ext3_sops;
        sb->s_export_op = &ext3_export_ops;
        sb->s_xattr = ext3_xattr_handlers;
#ifdef CONFIG_QUOTA
        sb->s_qcop = &ext3_qctl_operations;
        sb->dq_op = &ext3_quota_operations;
#endif
        INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */

        sb->s_root = NULL;

        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",
                                sb->s_id);
                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;
        }

        if (test_opt(sb, NOBH)) {
                if (sb->s_blocksize_bits != PAGE_CACHE_SHIFT) {
                        printk(KERN_WARNING "EXT3-fs: Ignoring nobh option "
                                "since filesystem blocksize doesn't match "
                                "pagesize\n");
                        clear_opt(sbi->s_mount_opt, NOBH);
                }
                if (!(test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)) {
                        printk(KERN_WARNING "EXT3-fs: Ignoring nobh option - "
                                "its supported only with writeback mode\n");
                        clear_opt(sbi->s_mount_opt, NOBH);
                }
        }
        /*
         * The journal_load will have done any necessary log recovery,
         * so we can safely mount the rest of the filesystem now.
         */

        root = iget(sb, EXT3_ROOT_INO);
        sb->s_root = d_alloc_root(root);
        if (!sb->s_root) {
                printk(KERN_ERR "EXT3-fs: get root inode failed\n");
                iput(root);
                goto failed_mount3;
        }
        if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
                dput(sb->s_root);
                sb->s_root = NULL;
                printk(KERN_ERR "EXT3-fs: corrupt root inode, run e2fsck\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;
        ext3_orphan_cleanup(sb, es);
        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");

        percpu_counter_mod(&sbi->s_freeblocks_counter,
                ext3_count_free_blocks(sb));
        percpu_counter_mod(&sbi->s_freeinodes_counter,
                ext3_count_free_inodes(sb));
        percpu_counter_mod(&sbi->s_dirs_counter,
                ext3_count_dirs(sb));

        lock_kernel();
        return 0;

cantfind_ext3:
        if (!silent)
                printk(KERN_ERR "VFS: Can't find ext3 filesystem on dev %s.\n",
                       sb->s_id);
        goto failed_mount;

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:
#ifdef CONFIG_QUOTA
        for (i = 0; i < MAXQUOTAS; i++)
                kfree(sbi->s_qf_names[i]);
#endif
        ext3_blkdev_remove(sbi);
        brelse(bh);
out_fail:
        sb->s_fs_info = NULL;
        kfree(sbi);
        lock_kernel();
        return -EINVAL;
}

/*
 * 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 super_block *sb, journal_t *journal)
{
        struct ext3_sb_info *sbi = EXT3_SB(sb);

        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. */

        spin_lock(&journal->j_state_lock);
        if (test_opt(sb, BARRIER))
                journal->j_flags |= JFS_BARRIER;
        else
                journal->j_flags &= ~JFS_BARRIER;
        spin_unlock(&journal->j_state_lock);
}

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);
                return NULL;
        }
        journal->j_private = sb;
        ext3_init_journal_params(sb, journal);
        return journal;
}

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

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

        if (bd_claim(bdev, sb)) {
                printk(KERN_ERR
                        "EXT3: failed to claim external journal device.\n");
                blkdev_put(bdev);
                return NULL;
        }

        blocksize = sb->s_blocksize;
        hblock = bdev_hardsect_size(bdev);
        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(bdev, blocksize);
        if (!(bh = __bread(bdev, 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(bdev, sb->s_bdev,
                                        start, len, blocksize);
        if (!journal) {
                printk(KERN_ERR "EXT3-fs: failed to create device journal\n");
                goto out_bdev;
        }
        journal->j_private = sb;
        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 (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
                printk(KERN_ERR "EXT3-fs: External journal has more than one "
                                        "user (unsupported) - %d\n",
                        be32_to_cpu(journal->j_superblock->s_nr_users));
                goto out_journal;
        }
        EXT3_SB(sb)->journal_bdev = bdev;
        ext3_init_journal_params(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);
        dev_t journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
        int err = 0;
        int really_read_only;

        really_read_only = bdev_read_only(sb->s_bdev);

        /*
         * 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)
{
        struct buffer_head *sbh = EXT3_SB(sb)->s_sbh;

        if (!sbh)
                return;
        es->s_wtime = cpu_to_le32(get_seconds());
        es->s_free_blocks_count = cpu_to_le32(ext3_count_free_blocks(sb));
        es->s_free_inodes_count = cpu_to_le32(ext3_count_free_inodes(sb));
        BUFFER_TRACE(sbh, "marking dirty");
        mark_buffer_dirty(sbh);
        if (sync)
                sync_dirty_buffer(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_t *journal = EXT3_SB(sb)->s_journal;

        journal_lock_updates(journal);
        journal_flush(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);
        }
        journal_unlock_updates(journal);
}

/*
 * 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.");

                EXT3_SB(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;
        ret = ext3_journal_force_commit(journal);
        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().
 */

static void ext3_write_super (struct super_block * sb)
{
        if (down_trylock(&sb->s_lock) == 0)
                BUG();
        sb->s_dirt = 0;
}

static int ext3_sync_fs(struct super_block *sb, int wait)
{
        tid_t target;

        sb->s_dirt = 0;
        if (journal_start_commit(EXT3_SB(sb)->s_journal, &target)) {
                if (wait)
                        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.
 */
static void ext3_write_super_lockfs(struct super_block *sb)
{
        sb->s_dirt = 0;

        if (!(sb->s_flags & MS_RDONLY)) {
                journal_t *journal = EXT3_SB(sb)->s_journal;

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

                /* 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);
        }
}

/*
 * 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.
 */
static void ext3_unlockfs(struct super_block *sb)
{
        if (!(sb->s_flags & MS_RDONLY)) {
                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);
        }
}

static 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;
        unsigned long n_blocks_count = 0;

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

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

        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
                ((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);

        es = sbi->s_es;

        ext3_init_journal_params(sb, sbi->s_journal);

        if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
                n_blocks_count > le32_to_cpu(es->s_blocks_count)) {
                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 {
                        __le32 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",
                                       sb->s_id, le32_to_cpu(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 ((ret = ext3_group_extend(sb, es, n_blocks_count)))
                                return ret;
                        if (!ext3_setup_super (sb, es, 0))
                                sb->s_flags &= ~MS_RDONLY;
                }
        }
        return 0;
}

static int ext3_statfs (struct super_block * sb, struct kstatfs * 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 {
                unsigned long ngroups;
                ngroups = EXT3_SB(sb)->s_groups_count;
                smp_rmb();

                /*
                 * 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 < ngroups; i++) {
                        overhead += ext3_bg_has_super(sb, i) +
                                ext3_bg_num_gdb(sb, i);
                        cond_resched();
                }

                /*
                 * Every block group has an inode bitmap, a block
                 * bitmap, and an inode table.
                 */
                overhead += (ngroups * (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;
}

/* Helper function for writing quotas on sync - we need to start transaction before quota file
 * is locked for write. Otherwise the are possible deadlocks:
 * Process 1                         Process 2
 * ext3_create()                     quota_sync()
 *   journal_start()                   write_dquot()
 *   DQUOT_INIT()                        down(dqio_sem)
 *     down(dqio_sem)                    journal_start()
 *
 */

#ifdef CONFIG_QUOTA

static inline struct inode *dquot_to_inode(struct dquot *dquot)
{
        return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
}

static int ext3_dquot_initialize(struct inode *inode, int type)
{
        handle_t *handle;
        int ret, err;

        /* We may create quota structure so we need to reserve enough blocks */
        handle = ext3_journal_start(inode, 2*EXT3_QUOTA_INIT_BLOCKS);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_initialize(inode, type);
        err = ext3_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext3_dquot_drop(struct inode *inode)
{
        handle_t *handle;
        int ret, err;

        /* We may delete quota structure so we need to reserve enough blocks */
        handle = ext3_journal_start(inode, 2*EXT3_QUOTA_INIT_BLOCKS);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_drop(inode);
        err = ext3_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext3_write_dquot(struct dquot *dquot)
{
        int ret, err;
        handle_t *handle;
        struct inode *inode;

        inode = dquot_to_inode(dquot);
        handle = ext3_journal_start(inode,
                                        EXT3_QUOTA_TRANS_BLOCKS);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_commit(dquot);
        err = ext3_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext3_acquire_dquot(struct dquot *dquot)
{
        int ret, err;
        handle_t *handle;

        handle = ext3_journal_start(dquot_to_inode(dquot),
                                        EXT3_QUOTA_INIT_BLOCKS);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_acquire(dquot);
        err = ext3_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext3_release_dquot(struct dquot *dquot)
{
        int ret, err;
        handle_t *handle;

        handle = ext3_journal_start(dquot_to_inode(dquot),
                                        EXT3_QUOTA_INIT_BLOCKS);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_release(dquot);
        err = ext3_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext3_mark_dquot_dirty(struct dquot *dquot)
{
        /* Are we journalling quotas? */
        if (EXT3_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
            EXT3_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
                dquot_mark_dquot_dirty(dquot);
                return ext3_write_dquot(dquot);
        } else {
                return dquot_mark_dquot_dirty(dquot);
        }
}

static int ext3_write_info(struct super_block *sb, int type)
{
        int ret, err;
        handle_t *handle;

        /* Data block + inode block */
        handle = ext3_journal_start(sb->s_root->d_inode, 2);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_commit_info(sb, type);
        err = ext3_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

/*
 * Turn on quotas during mount time - we need to find
 * the quota file and such...
 */
static int ext3_quota_on_mount(struct super_block *sb, int type)
{
        int err;
        struct dentry *dentry;
        struct qstr name = { .name = EXT3_SB(sb)->s_qf_names[type],
                             .hash = 0,
                             .len = strlen(EXT3_SB(sb)->s_qf_names[type])};

        dentry = lookup_hash(&name, sb->s_root);
        if (IS_ERR(dentry))
                return PTR_ERR(dentry);
        err = vfs_quota_on_mount(type, EXT3_SB(sb)->s_jquota_fmt, dentry);
        /* Now invalidate and put the dentry - quota got its own reference
         * to inode and dentry has at least wrong hash so we had better
         * throw it away */
        d_invalidate(dentry);
        dput(dentry);
        return err;
}

/*
 * Standard function to be called on quota_on
 */
static int ext3_quota_on(struct super_block *sb, int type, int format_id,
                         char *path)
{
        int err;
        struct nameidata nd;

        /* Not journalling quota? */
        if (!EXT3_SB(sb)->s_qf_names[USRQUOTA] &&
            !EXT3_SB(sb)->s_qf_names[GRPQUOTA])
                return vfs_quota_on(sb, type, format_id, path);
        err = path_lookup(path, LOOKUP_FOLLOW, &nd);
        if (err)
                return err;
        /* Quotafile not on the same filesystem? */
        if (nd.mnt->mnt_sb != sb) {
                path_release(&nd);
                return -EXDEV;
        }
        /* Quotafile not of fs root? */
        if (nd.dentry->d_parent->d_inode != sb->s_root->d_inode)
                printk(KERN_WARNING
                        "EXT3-fs: Quota file not on filesystem root. "
                        "Journalled quota will not work.\n");
        path_release(&nd);
        return vfs_quota_on(sb, type, format_id, path);
}

/* Read data from quotafile - avoid pagecache and such because we cannot afford
 * acquiring the locks... As quota files are never truncated and quota code
 * itself serializes the operations (and noone else should touch the files)
 * we don't have to be afraid of races */
static ssize_t ext3_quota_read(struct super_block *sb, int type, char *data,
                               size_t len, loff_t off)
{
        struct inode *inode = sb_dqopt(sb)->files[type];
        sector_t blk = off >> EXT3_BLOCK_SIZE_BITS(sb);
        int err = 0;
        int offset = off & (sb->s_blocksize - 1);
        int tocopy;
        size_t toread;
        struct buffer_head *bh;
        loff_t i_size = i_size_read(inode);

        if (off > i_size)
                return 0;
        if (off+len > i_size)
                len = i_size-off;
        toread = len;
        while (toread > 0) {
                tocopy = sb->s_blocksize - offset < toread ?
                                sb->s_blocksize - offset : toread;
                bh = ext3_bread(NULL, inode, blk, 0, &err);
                if (err)
                        return err;
                if (!bh)        /* A hole? */
                        memset(data, 0, tocopy);
                else
                        memcpy(data, bh->b_data+offset, tocopy);
                brelse(bh);
                offset = 0;
                toread -= tocopy;
                data += tocopy;
                blk++;
        }
        return len;
}

/* Write to quotafile (we know the transaction is already started and has
 * enough credits) */
static ssize_t ext3_quota_write(struct super_block *sb, int type,
                                const char *data, size_t len, loff_t off)
{
        struct inode *inode = sb_dqopt(sb)->files[type];
        sector_t blk = off >> EXT3_BLOCK_SIZE_BITS(sb);
        int err = 0;
        int offset = off & (sb->s_blocksize - 1);
        int tocopy;
        int journal_quota = EXT3_SB(sb)->s_qf_names[type] != NULL;
        size_t towrite = len;
        struct buffer_head *bh;
        handle_t *handle = journal_current_handle();

        down(&inode->i_sem);
        while (towrite > 0) {
                tocopy = sb->s_blocksize - offset < towrite ?
                                sb->s_blocksize - offset : towrite;
                bh = ext3_bread(handle, inode, blk, 1, &err);
                if (!bh)
                        goto out;
                if (journal_quota) {
                        err = ext3_journal_get_write_access(handle, bh);
                        if (err) {
                                brelse(bh);
                                goto out;
                        }
                }
                lock_buffer(bh);
                memcpy(bh->b_data+offset, data, tocopy);
                flush_dcache_page(bh->b_page);
                unlock_buffer(bh);
                if (journal_quota)
                        err = ext3_journal_dirty_metadata(handle, bh);
                else {
                        /* Always do at least ordered writes for quotas */
                        err = ext3_journal_dirty_data(handle, bh);
                        mark_buffer_dirty(bh);
                }
                brelse(bh);
                if (err)
                        goto out;
                offset = 0;
                towrite -= tocopy;
                data += tocopy;
                blk++;
        }
out:
        if (len == towrite)
                return err;
        if (inode->i_size < off+len-towrite) {
                i_size_write(inode, off+len-towrite);
                EXT3_I(inode)->i_disksize = inode->i_size;
        }
        inode->i_version++;
        inode->i_mtime = inode->i_ctime = CURRENT_TIME;
        ext3_mark_inode_dirty(handle, inode);
        up(&inode->i_sem);
        return len - towrite;
}

#endif

static struct super_block *ext3_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, ext3_fill_super);
}

static struct file_system_type ext3_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "ext3",
        .get_sb         = ext3_get_sb,
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
};

static int __init init_ext3_fs(void)
{
        int err = init_ext3_xattr();
        if (err)
                return err;
        err = init_inodecache();
        if (err)
                goto out1;
        err = register_filesystem(&ext3_fs_type);
        if (err)
                goto out;
        return 0;
out:
        destroy_inodecache();
out1:
        exit_ext3_xattr();
        return err;
}

static void __exit exit_ext3_fs(void)
{
        unregister_filesystem(&ext3_fs_type);
        destroy_inodecache();
        exit_ext3_xattr();
}

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)