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/*

 *  linux/fs/minix/inode.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

 *  Copyright (C) 1996  Gertjan van Wingerde    (gertjan@cs.vu.nl)

 *      Minix V2 fs support.

 */

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/minix_fs.h>

#include <linux/kernel.h>

#include <linux/mm.h>

#include <linux/string.h>

#include <linux/stat.h>

#include <linux/locks.h>

#include <asm/system.h>

#include <asm/segment.h>

#include <asm/bitops.h>

void minix_put_inode(struct inode *inode)

{

        if (inode->i_nlink)

                return;

        inode->i_size = 0;

        minix_truncate(inode);

        minix_free_inode(inode);

}

static void minix_commit_super (struct super_block * sb,

                               struct minix_super_block * ms)

{

        mark_buffer_dirty(sb->u.minix_sb.s_sbh, 1);

        sb->s_dirt = 0;

}

void minix_write_super (struct super_block * sb)

{

        struct minix_super_block * ms;

        if (!(sb->s_flags & MS_RDONLY)) {

                ms = sb->u.minix_sb.s_ms;

                if (ms->s_state & MINIX_VALID_FS)

                        ms->s_state &= ~MINIX_VALID_FS;

                minix_commit_super (sb, ms);

        }

        sb->s_dirt = 0;

}

void minix_put_super(struct super_block *sb)

{

        int i;

        lock_super(sb);

        if (!(sb->s_flags & MS_RDONLY)) {

                sb->u.minix_sb.s_ms->s_state = sb->u.minix_sb.s_mount_state;

                mark_buffer_dirty(sb->u.minix_sb.s_sbh, 1);

        }

        sb->s_dev = 0;

        for(i = 0 ; i < MINIX_I_MAP_SLOTS ; i++)

                brelse(sb->u.minix_sb.s_imap[i]);

        for(i = 0 ; i < MINIX_Z_MAP_SLOTS ; i++)

                brelse(sb->u.minix_sb.s_zmap[i]);

        brelse (sb->u.minix_sb.s_sbh);

        unlock_super(sb);

        MOD_DEC_USE_COUNT;

        return;

}

static struct super_operations minix_sops = {

        minix_read_inode,

        NULL,

        minix_write_inode,

        minix_put_inode,

        minix_put_super,

        minix_write_super,

        minix_statfs,

        minix_remount

};

int minix_remount (struct super_block * sb, int * flags, char * data)

{

        struct minix_super_block * ms;

        ms = sb->u.minix_sb.s_ms;

        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))

                return 0;

        if (*flags & MS_RDONLY) {

                if (ms->s_state & MINIX_VALID_FS ||

                    !(sb->u.minix_sb.s_mount_state & MINIX_VALID_FS))

                        return 0;

                /* Mounting a rw partition read-only. */

                ms->s_state = sb->u.minix_sb.s_mount_state;

                mark_buffer_dirty(sb->u.minix_sb.s_sbh, 1);

                sb->s_dirt = 1;

                minix_commit_super (sb, ms);

        }

        else {

                /* Mount a partition which is read-only, read-write. */

                sb->u.minix_sb.s_mount_state = ms->s_state;

                ms->s_state &= ~MINIX_VALID_FS;

                mark_buffer_dirty(sb->u.minix_sb.s_sbh, 1);

                sb->s_dirt = 1;

                if (!(sb->u.minix_sb.s_mount_state & MINIX_VALID_FS))

                        printk ("MINIX-fs warning: remounting unchecked fs, "

                                "running fsck is recommended.\n");

                else if ((sb->u.minix_sb.s_mount_state & MINIX_ERROR_FS))

                        printk ("MINIX-fs warning: remounting fs with errors, "

                                "running fsck is recommended.\n");

        }

        return 0;

}

/*

 * Check the root directory of the filesystem to make sure

 * it really _is_ a minix filesystem, and to check the size

 * of the directory entry.

 */

static const char * minix_checkroot(struct super_block *s)

{

        struct inode * dir;

        struct buffer_head *bh;

        struct minix_dir_entry *de;

        const char * errmsg;

        int dirsize;

        dir = s->s_mounted;

        if (!S_ISDIR(dir->i_mode))

                return "root directory is not a directory";

        bh = minix_bread(dir, 0, 0);

        if (!bh)

                return "unable to read root directory";

        de = (struct minix_dir_entry *) bh->b_data;

        errmsg = "bad root directory '.' entry";

        dirsize = BLOCK_SIZE;

        if (de->inode == MINIX_ROOT_INO && strcmp(de->name, ".") == 0) {

                errmsg = "bad root directory '..' entry";

                dirsize = 8;

        }

        while ((dirsize <<= 1) < BLOCK_SIZE) {

                de = (struct minix_dir_entry *) (bh->b_data + dirsize);

                if (de->inode != MINIX_ROOT_INO)

                        continue;

                if (strcmp(de->name, ".."))

                        continue;

                s->u.minix_sb.s_dirsize = dirsize;

                s->u.minix_sb.s_namelen = dirsize - 2;

                errmsg = NULL;

                break;

        }

        brelse(bh);

        return errmsg;

}

struct super_block *minix_read_super(struct super_block *s,void *data,

                                     int silent)

{

        struct buffer_head *bh;

        struct minix_super_block *ms;

        int i, block;

        kdev_t dev = s->s_dev;

        const char * errmsg;

        if (32 != sizeof (struct minix_inode))

                panic("bad V1 i-node size");

        if (64 != sizeof(struct minix2_inode))

                panic("bad V2 i-node size");

        MOD_INC_USE_COUNT;

        lock_super(s);

        set_blocksize(dev, BLOCK_SIZE);

        if (!(bh = bread(dev,1,BLOCK_SIZE))) {

                s->s_dev = 0;

                unlock_super(s);

                printk("MINIX-fs: unable to read superblock\n");

                MOD_DEC_USE_COUNT;

                return NULL;

        }

        ms = (struct minix_super_block *) bh->b_data;

        s->u.minix_sb.s_ms = ms;

        s->u.minix_sb.s_sbh = bh;

        s->u.minix_sb.s_mount_state = ms->s_state;

        s->s_blocksize = 1024;

        s->s_blocksize_bits = 10;

        s->u.minix_sb.s_ninodes = ms->s_ninodes;

        s->u.minix_sb.s_imap_blocks = ms->s_imap_blocks;

        s->u.minix_sb.s_zmap_blocks = ms->s_zmap_blocks;

        s->u.minix_sb.s_firstdatazone = ms->s_firstdatazone;

        s->u.minix_sb.s_log_zone_size = ms->s_log_zone_size;

        s->u.minix_sb.s_max_size = ms->s_max_size;

        s->s_magic = ms->s_magic;

        if (s->s_magic == MINIX_SUPER_MAGIC) {

                s->u.minix_sb.s_version = MINIX_V1;

                s->u.minix_sb.s_nzones = ms->s_nzones;

                s->u.minix_sb.s_dirsize = 16;

                s->u.minix_sb.s_namelen = 14;

        } else if (s->s_magic == MINIX_SUPER_MAGIC2) {

                s->u.minix_sb.s_version = MINIX_V1;

                s->u.minix_sb.s_nzones = ms->s_nzones;

                s->u.minix_sb.s_dirsize = 32;

                s->u.minix_sb.s_namelen = 30;

        } else if (s->s_magic == MINIX2_SUPER_MAGIC) {

                s->u.minix_sb.s_version = MINIX_V2;

                s->u.minix_sb.s_nzones = ms->s_zones;

                s->u.minix_sb.s_dirsize = 16;

                s->u.minix_sb.s_namelen = 14;

        } else if (s->s_magic == MINIX2_SUPER_MAGIC2) {

                s->u.minix_sb.s_version = MINIX_V2;

                s->u.minix_sb.s_nzones = ms->s_zones;

                s->u.minix_sb.s_dirsize = 32;

                s->u.minix_sb.s_namelen = 30;

        } else {

                s->s_dev = 0;

                unlock_super(s);

                brelse(bh);

                if (!silent)

                        printk("VFS: Can't find a minix or minix V2 filesystem on dev "

                               "%s.\n", kdevname(dev));

                MOD_DEC_USE_COUNT;

                return NULL;

        }

        for (i=0;i < MINIX_I_MAP_SLOTS;i++)

                s->u.minix_sb.s_imap[i] = NULL;

        for (i=0;i < MINIX_Z_MAP_SLOTS;i++)

                s->u.minix_sb.s_zmap[i] = NULL;

        if (s->u.minix_sb.s_zmap_blocks > MINIX_Z_MAP_SLOTS) {

                s->s_dev = 0;

                unlock_super (s);

                brelse (bh);

                if (!silent)

                        printk ("MINIX-fs: filesystem too big\n");

                MOD_DEC_USE_COUNT;

                return NULL;

        }

        block=2;

        for (i=0 ; i < s->u.minix_sb.s_imap_blocks ; i++)

                if ((s->u.minix_sb.s_imap[i]=bread(dev,block,BLOCK_SIZE)) != NULL)

                        block++;

                else

                        break;

        for (i=0 ; i < s->u.minix_sb.s_zmap_blocks ; i++)

                if ((s->u.minix_sb.s_zmap[i]=bread(dev,block,BLOCK_SIZE)) != NULL)

                        block++;

                else

                        break;

        if (block != 2+s->u.minix_sb.s_imap_blocks+s->u.minix_sb.s_zmap_blocks) {

                for(i=0;i<MINIX_I_MAP_SLOTS;i++)

                        brelse(s->u.minix_sb.s_imap[i]);

                for(i=0;i<MINIX_Z_MAP_SLOTS;i++)

                        brelse(s->u.minix_sb.s_zmap[i]);

                s->s_dev = 0;

                unlock_super(s);

                brelse(bh);

                printk("MINIX-fs: bad superblock or unable to read bitmaps\n");

                MOD_DEC_USE_COUNT;

                return NULL;

        }

        set_bit(0,s->u.minix_sb.s_imap[0]->b_data);

        set_bit(0,s->u.minix_sb.s_zmap[0]->b_data);

        unlock_super(s);

        /* set up enough so that it can read an inode */

        s->s_dev = dev;

        s->s_op = &minix_sops;

        s->s_mounted = iget(s,MINIX_ROOT_INO);

        if (!s->s_mounted) {

                s->s_dev = 0;

                brelse(bh);

                if (!silent)

                        printk("MINIX-fs: get root inode failed\n");

                MOD_DEC_USE_COUNT;

                return NULL;

        }

        errmsg = minix_checkroot(s);

        if (errmsg) {

                if (!silent)

                        printk("MINIX-fs: %s\n", errmsg);

                iput (s->s_mounted);

                s->s_dev = 0;

                brelse (bh);

                MOD_DEC_USE_COUNT;

                return NULL;

        }

        if (!(s->s_flags & MS_RDONLY)) {

                ms->s_state &= ~MINIX_VALID_FS;

                mark_buffer_dirty(bh, 1);

                s->s_dirt = 1;

        }

        if (!(s->u.minix_sb.s_mount_state & MINIX_VALID_FS))

                printk ("MINIX-fs: mounting unchecked file system, "

                        "running fsck is recommended.\n");

        else if (s->u.minix_sb.s_mount_state & MINIX_ERROR_FS)

                printk ("MINIX-fs: mounting file system with errors, "

                        "running fsck is recommended.\n");

        return s;

}

void minix_statfs(struct super_block *sb, struct statfs *buf, int bufsiz)

{

        struct statfs tmp;

        tmp.f_type = sb->s_magic;

        tmp.f_bsize = sb->s_blocksize;

        tmp.f_blocks = (sb->u.minix_sb.s_nzones - sb->u.minix_sb.s_firstdatazone) << sb->u.minix_sb.s_log_zone_size;

        tmp.f_bfree = minix_count_free_blocks(sb);

        tmp.f_bavail = tmp.f_bfree;

        tmp.f_files = sb->u.minix_sb.s_ninodes;

        tmp.f_ffree = minix_count_free_inodes(sb);

        tmp.f_namelen = sb->u.minix_sb.s_namelen;

        memcpy_tofs(buf, &tmp, bufsiz);

}

/*

 * The minix V1 fs bmap functions.

 */

#define V1_inode_bmap(inode,nr) (((unsigned short *)(inode)->u.minix_i.u.i1_data)[(nr)])

static int V1_block_bmap(struct buffer_head * bh, int nr)

{

        int tmp;

        if (!bh)

                return 0;

        tmp = ((unsigned short *) bh->b_data)[nr];

        brelse(bh);

        return tmp;

}

static int V1_minix_bmap(struct inode * inode,int block)

{

        int i;

        if (block<0) {

                printk("minix_bmap: block<0");

                return 0;

        }

        if (block >= (inode->i_sb->u.minix_sb.s_max_size/BLOCK_SIZE)) {

                printk("minix_bmap: block>big");

                return 0;

        }

        if (block < 7)

                return V1_inode_bmap(inode,block);

        block -= 7;

        if (block < 512) {

                i = V1_inode_bmap(inode,7);

                if (!i)

                        return 0;

                return V1_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block);

        }

        block -= 512;

        i = V1_inode_bmap(inode,8);

        if (!i)

                return 0;

        i = V1_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block>>9);

        if (!i)

                return 0;

        return V1_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block & 511);

}

/*

 * The minix V2 fs bmap functions.

 */

#define V2_inode_bmap(inode,nr) (((unsigned long  *)(inode)->u.minix_i.u.i2_data)[(nr)])

static int V2_block_bmap(struct buffer_head * bh, int nr)

{

        int tmp;

        if (!bh)

                return 0;

        tmp = ((unsigned long *) bh->b_data)[nr];

        brelse(bh);

        return tmp;

}

static int V2_minix_bmap(struct inode * inode,int block)

{

        int i;

        if (block<0) {

                printk("minix_bmap: block<0");

                return 0;

        }

        if (block >= (inode->i_sb->u.minix_sb.s_max_size/BLOCK_SIZE)) {

                printk("minix_bmap: block>big");

                return 0;

        }

        if (block < 7)

                return V2_inode_bmap(inode,block);

        block -= 7;

        if (block < 256) {

                i = V2_inode_bmap(inode,7);

                if (!i)

                        return 0;

                return V2_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block);

        }

        block -= 256;

        if (block < 256*256) {

                i = V2_inode_bmap(inode,8);

                if (!i)

                        return 0;

                i = V2_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block >> 8);

                if (!i)

                        return 0;

                return V2_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block & 255);

        }

        block -= 256*256;

        i = V2_inode_bmap(inode,9);

        if (!i)

                return 0;

        i = V2_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block >> 16);

        if (!i)

                return 0;

        i = V2_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),(block >> 8) & 255);

        if (!i)

                return 0;

        return V2_block_bmap(bread(inode->i_dev,i,BLOCK_SIZE),block & 255);

}

/*

 * The global minix fs bmap function.

 */

int minix_bmap(struct inode * inode,int block)

{

        if (INODE_VERSION(inode) == MINIX_V1)

                return V1_minix_bmap(inode, block);

        else

                return V2_minix_bmap(inode, block);

}

/*

 * The minix V1 fs getblk functions.

 */

static struct buffer_head * V1_inode_getblk(struct inode * inode, int nr,

                                            int create)

{

        int tmp;

        unsigned short *p;

        struct buffer_head * result;

        p = inode->u.minix_i.u.i1_data + nr;

repeat:

        tmp = *p;

        if (tmp) {

                result = getblk(inode->i_dev, tmp, BLOCK_SIZE);

                if (tmp == *p)

                        return result;

                brelse(result);

                goto repeat;

        }

        if (!create)

                return NULL;

        tmp = minix_new_block(inode->i_sb);

        if (!tmp)

                return NULL;

        result = getblk(inode->i_dev, tmp, BLOCK_SIZE);

        if (*p) {

                minix_free_block(inode->i_sb,tmp);

                brelse(result);

                goto repeat;

        }

        *p = tmp;

        inode->i_ctime = CURRENT_TIME;

        inode->i_dirt = 1;

        return result;

}

static struct buffer_head * V1_block_getblk(struct inode * inode,

        struct buffer_head * bh, int nr, int create)

{

        int tmp;

        unsigned short *p;

        struct buffer_head * result;

        if (!bh)

                return NULL;

        if (!buffer_uptodate(bh)) {

                ll_rw_block(READ, 1, &bh);

                wait_on_buffer(bh);

                if (!buffer_uptodate(bh)) {

                        brelse(bh);

                        return NULL;

                }

        }

        p = nr + (unsigned short *) bh->b_data;

repeat:

        tmp = *p;

        if (tmp) {

                result = getblk(bh->b_dev, tmp, BLOCK_SIZE);

                if (tmp == *p) {

                        brelse(bh);

                        return result;

                }

                brelse(result);

                goto repeat;

        }

        if (!create) {

                brelse(bh);

                return NULL;

        }

        tmp = minix_new_block(inode->i_sb);

        if (!tmp) {

                brelse(bh);

                return NULL;

        }

        result = getblk(bh->b_dev, tmp, BLOCK_SIZE);

        if (*p) {

                minix_free_block(inode->i_sb,tmp);

                brelse(result);

                goto repeat;

        }

        *p = tmp;

        mark_buffer_dirty(bh, 1);

        brelse(bh);

        return result;

}

static struct buffer_head * V1_minix_getblk(struct inode * inode, int block,

                                            int create)

{

        struct buffer_head * bh;

        if (block<0) {

                printk("minix_getblk: block<0");

                return NULL;

        }

        if (block >= inode->i_sb->u.minix_sb.s_max_size/BLOCK_SIZE) {

                printk("minix_getblk: block>big");

                return NULL;

        }

        if (block < 7)

                return V1_inode_getblk(inode,block,create);

        block -= 7;

        if (block < 512) {

                bh = V1_inode_getblk(inode,7,create);

                return V1_block_getblk(inode, bh, block, create);

        }

        block -= 512;

        bh = V1_inode_getblk(inode,8,create);

        bh = V1_block_getblk(inode, bh, (block>>9) & 511, create);

        return V1_block_getblk(inode, bh, block & 511, create);

}

/*

 * The minix V2 fs getblk functions.

 */

static struct buffer_head * V2_inode_getblk(struct inode * inode, int nr,

                                            int create)

{

        int tmp;

        unsigned long *p;

        struct buffer_head * result;

        p = (unsigned long *) inode->u.minix_i.u.i2_data + nr;

repeat:

        tmp = *p;

        if (tmp) {

                result = getblk(inode->i_dev, tmp, BLOCK_SIZE);

                if (tmp == *p)

                        return result;

                brelse(result);

                goto repeat;

        }

        if (!create)

                return NULL;

        tmp = minix_new_block(inode->i_sb);

        if (!tmp)

                return NULL;

        result = getblk(inode->i_dev, tmp, BLOCK_SIZE);

        if (*p) {

                minix_free_block(inode->i_sb,tmp);

                brelse(result);

                goto repeat;

        }

        *p = tmp;

        inode->i_ctime = CURRENT_TIME;

        inode->i_dirt = 1;

        return result;

}

static struct buffer_head * V2_block_getblk(struct inode * inode,

        struct buffer_head * bh, int nr, int create)

{

        int tmp;

        unsigned long *p;

        struct buffer_head * result;

        if (!bh)

                return NULL;

        if (!buffer_uptodate(bh)) {

                ll_rw_block(READ, 1, &bh);

                wait_on_buffer(bh);

                if (!buffer_uptodate(bh)) {

                        brelse(bh);

                        return NULL;

                }

        }

        p = nr + (unsigned long *) bh->b_data;

repeat:

        tmp = *p;

        if (tmp) {

                result = getblk(bh->b_dev, tmp, BLOCK_SIZE);

                if (tmp == *p) {