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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [fat/] [fatent.c] - Blame information for rev 62

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/*
 * Copyright (C) 2004, OGAWA Hirofumi
 * Released under GPL v2.
 */
 
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/msdos_fs.h>
 
struct fatent_operations {
        void (*ent_blocknr)(struct super_block *, int, int *, sector_t *);
        void (*ent_set_ptr)(struct fat_entry *, int);
        int (*ent_bread)(struct super_block *, struct fat_entry *,
                         int, sector_t);
        int (*ent_get)(struct fat_entry *);
        void (*ent_put)(struct fat_entry *, int);
        int (*ent_next)(struct fat_entry *);
};
 
static DEFINE_SPINLOCK(fat12_entry_lock);
 
static void fat12_ent_blocknr(struct super_block *sb, int entry,
                              int *offset, sector_t *blocknr)
{
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
        int bytes = entry + (entry >> 1);
        WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry);
        *offset = bytes & (sb->s_blocksize - 1);
        *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
}
 
static void fat_ent_blocknr(struct super_block *sb, int entry,
                            int *offset, sector_t *blocknr)
{
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
        int bytes = (entry << sbi->fatent_shift);
        WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry);
        *offset = bytes & (sb->s_blocksize - 1);
        *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
}
 
static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset)
{
        struct buffer_head **bhs = fatent->bhs;
        if (fatent->nr_bhs == 1) {
                WARN_ON(offset >= (bhs[0]->b_size - 1));
                fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
                fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1);
        } else {
                WARN_ON(offset != (bhs[0]->b_size - 1));
                fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
                fatent->u.ent12_p[1] = bhs[1]->b_data;
        }
}
 
static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset)
{
        WARN_ON(offset & (2 - 1));
        fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset);
}
 
static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset)
{
        WARN_ON(offset & (4 - 1));
        fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset);
}
 
static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent,
                           int offset, sector_t blocknr)
{
        struct buffer_head **bhs = fatent->bhs;
 
        WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
        bhs[0] = sb_bread(sb, blocknr);
        if (!bhs[0])
                goto err;
 
        if ((offset + 1) < sb->s_blocksize)
                fatent->nr_bhs = 1;
        else {
                /* This entry is block boundary, it needs the next block */
                blocknr++;
                bhs[1] = sb_bread(sb, blocknr);
                if (!bhs[1])
                        goto err_brelse;
                fatent->nr_bhs = 2;
        }
        fat12_ent_set_ptr(fatent, offset);
        return 0;
 
err_brelse:
        brelse(bhs[0]);
err:
        printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n",
               (unsigned long long)blocknr);
        return -EIO;
}
 
static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent,
                         int offset, sector_t blocknr)
{
        struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
 
        WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
        fatent->bhs[0] = sb_bread(sb, blocknr);
        if (!fatent->bhs[0]) {
                printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n",
                       (unsigned long long)blocknr);
                return -EIO;
        }
        fatent->nr_bhs = 1;
        ops->ent_set_ptr(fatent, offset);
        return 0;
}
 
static int fat12_ent_get(struct fat_entry *fatent)
{
        u8 **ent12_p = fatent->u.ent12_p;
        int next;
 
        spin_lock(&fat12_entry_lock);
        if (fatent->entry & 1)
                next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4);
        else
                next = (*ent12_p[1] << 8) | *ent12_p[0];
        spin_unlock(&fat12_entry_lock);
 
        next &= 0x0fff;
        if (next >= BAD_FAT12)
                next = FAT_ENT_EOF;
        return next;
}
 
static int fat16_ent_get(struct fat_entry *fatent)
{
        int next = le16_to_cpu(*fatent->u.ent16_p);
        WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1));
        if (next >= BAD_FAT16)
                next = FAT_ENT_EOF;
        return next;
}
 
static int fat32_ent_get(struct fat_entry *fatent)
{
        int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff;
        WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1));
        if (next >= BAD_FAT32)
                next = FAT_ENT_EOF;
        return next;
}
 
static void fat12_ent_put(struct fat_entry *fatent, int new)
{
        u8 **ent12_p = fatent->u.ent12_p;
 
        if (new == FAT_ENT_EOF)
                new = EOF_FAT12;
 
        spin_lock(&fat12_entry_lock);
        if (fatent->entry & 1) {
                *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f);
                *ent12_p[1] = new >> 4;
        } else {
                *ent12_p[0] = new & 0xff;
                *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8);
        }
        spin_unlock(&fat12_entry_lock);
 
        mark_buffer_dirty(fatent->bhs[0]);
        if (fatent->nr_bhs == 2)
                mark_buffer_dirty(fatent->bhs[1]);
}
 
static void fat16_ent_put(struct fat_entry *fatent, int new)
{
        if (new == FAT_ENT_EOF)
                new = EOF_FAT16;
 
        *fatent->u.ent16_p = cpu_to_le16(new);
        mark_buffer_dirty(fatent->bhs[0]);
}
 
static void fat32_ent_put(struct fat_entry *fatent, int new)
{
        if (new == FAT_ENT_EOF)
                new = EOF_FAT32;
 
        WARN_ON(new & 0xf0000000);
        new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff;
        *fatent->u.ent32_p = cpu_to_le32(new);
        mark_buffer_dirty(fatent->bhs[0]);
}
 
static int fat12_ent_next(struct fat_entry *fatent)
{
        u8 **ent12_p = fatent->u.ent12_p;
        struct buffer_head **bhs = fatent->bhs;
        u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1);
 
        fatent->entry++;
        if (fatent->nr_bhs == 1) {
                WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 2)));
                WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));
                if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) {
                        ent12_p[0] = nextp - 1;
                        ent12_p[1] = nextp;
                        return 1;
                }
        } else {
                WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));
                WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data);
                ent12_p[0] = nextp - 1;
                ent12_p[1] = nextp;
                brelse(bhs[0]);
                bhs[0] = bhs[1];
                fatent->nr_bhs = 1;
                return 1;
        }
        ent12_p[0] = NULL;
        ent12_p[1] = NULL;
        return 0;
}
 
static int fat16_ent_next(struct fat_entry *fatent)
{
        const struct buffer_head *bh = fatent->bhs[0];
        fatent->entry++;
        if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) {
                fatent->u.ent16_p++;
                return 1;
        }
        fatent->u.ent16_p = NULL;
        return 0;
}
 
static int fat32_ent_next(struct fat_entry *fatent)
{
        const struct buffer_head *bh = fatent->bhs[0];
        fatent->entry++;
        if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) {
                fatent->u.ent32_p++;
                return 1;
        }
        fatent->u.ent32_p = NULL;
        return 0;
}
 
static struct fatent_operations fat12_ops = {
        .ent_blocknr    = fat12_ent_blocknr,
        .ent_set_ptr    = fat12_ent_set_ptr,
        .ent_bread      = fat12_ent_bread,
        .ent_get        = fat12_ent_get,
        .ent_put        = fat12_ent_put,
        .ent_next       = fat12_ent_next,
};
 
static struct fatent_operations fat16_ops = {
        .ent_blocknr    = fat_ent_blocknr,
        .ent_set_ptr    = fat16_ent_set_ptr,
        .ent_bread      = fat_ent_bread,
        .ent_get        = fat16_ent_get,
        .ent_put        = fat16_ent_put,
        .ent_next       = fat16_ent_next,
};
 
static struct fatent_operations fat32_ops = {
        .ent_blocknr    = fat_ent_blocknr,
        .ent_set_ptr    = fat32_ent_set_ptr,
        .ent_bread      = fat_ent_bread,
        .ent_get        = fat32_ent_get,
        .ent_put        = fat32_ent_put,
        .ent_next       = fat32_ent_next,
};
 
static inline void lock_fat(struct msdos_sb_info *sbi)
{
        mutex_lock(&sbi->fat_lock);
}
 
static inline void unlock_fat(struct msdos_sb_info *sbi)
{
        mutex_unlock(&sbi->fat_lock);
}
 
void fat_ent_access_init(struct super_block *sb)
{
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 
        mutex_init(&sbi->fat_lock);
 
        switch (sbi->fat_bits) {
        case 32:
                sbi->fatent_shift = 2;
                sbi->fatent_ops = &fat32_ops;
                break;
        case 16:
                sbi->fatent_shift = 1;
                sbi->fatent_ops = &fat16_ops;
                break;
        case 12:
                sbi->fatent_shift = -1;
                sbi->fatent_ops = &fat12_ops;
                break;
        }
}
 
static inline int fat_ent_update_ptr(struct super_block *sb,
                                     struct fat_entry *fatent,
                                     int offset, sector_t blocknr)
{
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
        struct fatent_operations *ops = sbi->fatent_ops;
        struct buffer_head **bhs = fatent->bhs;
 
        /* Is this fatent's blocks including this entry? */
        if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
                return 0;
        /* Does this entry need the next block? */
        if (sbi->fat_bits == 12 && (offset + 1) >= sb->s_blocksize) {
                if (fatent->nr_bhs != 2 || bhs[1]->b_blocknr != (blocknr + 1))
                        return 0;
        }
        ops->ent_set_ptr(fatent, offset);
        return 1;
}
 
int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry)
{
        struct super_block *sb = inode->i_sb;
        struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
        struct fatent_operations *ops = sbi->fatent_ops;
        int err, offset;
        sector_t blocknr;
 
        if (entry < FAT_START_ENT || sbi->max_cluster <= entry) {
                fatent_brelse(fatent);
                fat_fs_panic(sb, "invalid access to FAT (entry 0x%08x)", entry);
                return -EIO;
        }
 
        fatent_set_entry(fatent, entry);
        ops->ent_blocknr(sb, entry, &offset, &blocknr);
 
        if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) {
                fatent_brelse(fatent);
                err = ops->ent_bread(sb, fatent, offset, blocknr);
                if (err)
                        return err;
        }
        return ops->ent_get(fatent);
}
 
/* FIXME: We can write the blocks as more big chunk. */
static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs,
                          int nr_bhs)
{
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
        struct buffer_head *c_bh;
        int err, n, copy;
 
        err = 0;
        for (copy = 1; copy < sbi->fats; copy++) {
                sector_t backup_fat = sbi->fat_length * copy;
 
                for (n = 0; n < nr_bhs; n++) {
                        c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr);
                        if (!c_bh) {
                                err = -ENOMEM;
                                goto error;
                        }
                        memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize);
                        set_buffer_uptodate(c_bh);
                        mark_buffer_dirty(c_bh);
                        if (sb->s_flags & MS_SYNCHRONOUS)
                                err = sync_dirty_buffer(c_bh);
                        brelse(c_bh);
                        if (err)
                                goto error;
                }
        }
error:
        return err;
}
 
int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
                  int new, int wait)
{
        struct super_block *sb = inode->i_sb;
        struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
        int err;
 
        ops->ent_put(fatent, new);
        if (wait) {
                err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs);
                if (err)
                        return err;
        }
        return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs);
}
 
static inline int fat_ent_next(struct msdos_sb_info *sbi,
                               struct fat_entry *fatent)
{
        if (sbi->fatent_ops->ent_next(fatent)) {
                if (fatent->entry < sbi->max_cluster)
                        return 1;
        }
        return 0;
}
 
static inline int fat_ent_read_block(struct super_block *sb,
                                     struct fat_entry *fatent)
{
        struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
        sector_t blocknr;
        int offset;
 
        fatent_brelse(fatent);
        ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
        return ops->ent_bread(sb, fatent, offset, blocknr);
}
 
static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs,
                            struct fat_entry *fatent)
{
        int n, i;
 
        for (n = 0; n < fatent->nr_bhs; n++) {
                for (i = 0; i < *nr_bhs; i++) {
                        if (fatent->bhs[n] == bhs[i])
                                break;
                }
                if (i == *nr_bhs) {
                        get_bh(fatent->bhs[n]);
                        bhs[i] = fatent->bhs[n];
                        (*nr_bhs)++;
                }
        }
}
 
int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
{
        struct super_block *sb = inode->i_sb;
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
        struct fatent_operations *ops = sbi->fatent_ops;
        struct fat_entry fatent, prev_ent;
        struct buffer_head *bhs[MAX_BUF_PER_PAGE];
        int i, count, err, nr_bhs, idx_clus;
 
        BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2));    /* fixed limit */
 
        lock_fat(sbi);
        if (sbi->free_clusters != -1 && sbi->free_clusters < nr_cluster) {
                unlock_fat(sbi);
                return -ENOSPC;
        }
 
        err = nr_bhs = idx_clus = 0;
        count = FAT_START_ENT;
        fatent_init(&prev_ent);
        fatent_init(&fatent);
        fatent_set_entry(&fatent, sbi->prev_free + 1);
        while (count < sbi->max_cluster) {
                if (fatent.entry >= sbi->max_cluster)
                        fatent.entry = FAT_START_ENT;
                fatent_set_entry(&fatent, fatent.entry);
                err = fat_ent_read_block(sb, &fatent);
                if (err)
                        goto out;
 
                /* Find the free entries in a block */
                do {
                        if (ops->ent_get(&fatent) == FAT_ENT_FREE) {
                                int entry = fatent.entry;
 
                                /* make the cluster chain */
                                ops->ent_put(&fatent, FAT_ENT_EOF);
                                if (prev_ent.nr_bhs)
                                        ops->ent_put(&prev_ent, entry);
 
                                fat_collect_bhs(bhs, &nr_bhs, &fatent);
 
                                sbi->prev_free = entry;
                                if (sbi->free_clusters != -1)
                                        sbi->free_clusters--;
                                sb->s_dirt = 1;
 
                                cluster[idx_clus] = entry;
                                idx_clus++;
                                if (idx_clus == nr_cluster)
                                        goto out;
 
                                /*
                                 * fat_collect_bhs() gets ref-count of bhs,
                                 * so we can still use the prev_ent.
                                 */
                                prev_ent = fatent;
                        }
                        count++;
                        if (count == sbi->max_cluster)
                                break;
                } while (fat_ent_next(sbi, &fatent));
        }
 
        /* Couldn't allocate the free entries */
        sbi->free_clusters = 0;
        sb->s_dirt = 1;
        err = -ENOSPC;
 
out:
        unlock_fat(sbi);
        fatent_brelse(&fatent);
        if (!err) {
                if (inode_needs_sync(inode))
                        err = fat_sync_bhs(bhs, nr_bhs);
                if (!err)
                        err = fat_mirror_bhs(sb, bhs, nr_bhs);
        }
        for (i = 0; i < nr_bhs; i++)
                brelse(bhs[i]);
 
        if (err && idx_clus)
                fat_free_clusters(inode, cluster[0]);
 
        return err;
}
 
int fat_free_clusters(struct inode *inode, int cluster)
{
        struct super_block *sb = inode->i_sb;
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
        struct fatent_operations *ops = sbi->fatent_ops;
        struct fat_entry fatent;
        struct buffer_head *bhs[MAX_BUF_PER_PAGE];
        int i, err, nr_bhs;
 
        nr_bhs = 0;
        fatent_init(&fatent);
        lock_fat(sbi);
        do {
                cluster = fat_ent_read(inode, &fatent, cluster);
                if (cluster < 0) {
                        err = cluster;
                        goto error;
                } else if (cluster == FAT_ENT_FREE) {
                        fat_fs_panic(sb, "%s: deleting FAT entry beyond EOF",
                                     __FUNCTION__);
                        err = -EIO;
                        goto error;
                }
 
                ops->ent_put(&fatent, FAT_ENT_FREE);
                if (sbi->free_clusters != -1) {
                        sbi->free_clusters++;
                        sb->s_dirt = 1;
                }
 
                if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) {
                        if (sb->s_flags & MS_SYNCHRONOUS) {
                                err = fat_sync_bhs(bhs, nr_bhs);
                                if (err)
                                        goto error;
                        }
                        err = fat_mirror_bhs(sb, bhs, nr_bhs);
                        if (err)
                                goto error;
                        for (i = 0; i < nr_bhs; i++)
                                brelse(bhs[i]);
                        nr_bhs = 0;
                }
                fat_collect_bhs(bhs, &nr_bhs, &fatent);
        } while (cluster != FAT_ENT_EOF);
 
        if (sb->s_flags & MS_SYNCHRONOUS) {
                err = fat_sync_bhs(bhs, nr_bhs);
                if (err)
                        goto error;
        }
        err = fat_mirror_bhs(sb, bhs, nr_bhs);
error:
        fatent_brelse(&fatent);
        for (i = 0; i < nr_bhs; i++)
                brelse(bhs[i]);
        unlock_fat(sbi);
 
        fat_clusters_flush(sb);
 
        return err;
}
 
EXPORT_SYMBOL_GPL(fat_free_clusters);
 
/* 128kb is the whole sectors for FAT12 and FAT16 */
#define FAT_READA_SIZE          (128 * 1024)
 
static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent,
                          unsigned long reada_blocks)
{
        struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
        sector_t blocknr;
        int i, offset;
 
        ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
 
        for (i = 0; i < reada_blocks; i++)
                sb_breadahead(sb, blocknr + i);
}
 
int fat_count_free_clusters(struct super_block *sb)
{
        struct msdos_sb_info *sbi = MSDOS_SB(sb);
        struct fatent_operations *ops = sbi->fatent_ops;
        struct fat_entry fatent;
        unsigned long reada_blocks, reada_mask, cur_block;
        int err = 0, free;
 
        lock_fat(sbi);
        if (sbi->free_clusters != -1)
                goto out;
 
        reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
        reada_mask = reada_blocks - 1;
        cur_block = 0;
 
        free = 0;
        fatent_init(&fatent);
        fatent_set_entry(&fatent, FAT_START_ENT);
        while (fatent.entry < sbi->max_cluster) {
                /* readahead of fat blocks */
                if ((cur_block & reada_mask) == 0) {
                        unsigned long rest = sbi->fat_length - cur_block;
                        fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
                }
                cur_block++;
 
                err = fat_ent_read_block(sb, &fatent);
                if (err)
                        goto out;
 
                do {
                        if (ops->ent_get(&fatent) == FAT_ENT_FREE)
                                free++;
                } while (fat_ent_next(sbi, &fatent));
        }
        sbi->free_clusters = free;
        sb->s_dirt = 1;
        fatent_brelse(&fatent);
out:
        unlock_fat(sbi);
        return err;
}

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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [fat/] [fatent.c] - Blame information for rev 62

Line No.	Rev	Author	Line
1	62	marcus.erl	`/*`
2			`* Copyright (C) 2004, OGAWA Hirofumi`
3			`* Released under GPL v2.`
4			`*/`
5
6			`#include <linux/module.h>`
7			`#include <linux/fs.h>`
8			`#include <linux/msdos_fs.h>`
9
10			`struct fatent_operations {`
11			`void (ent_blocknr)(struct super_block , int, int , sector_t );`
12			`void (ent_set_ptr)(struct fat_entry , int);`
13			`int (ent_bread)(struct super_block , struct fat_entry *,`
14			`int, sector_t);`
15			`int (ent_get)(struct fat_entry );`
16			`void (ent_put)(struct fat_entry , int);`
17			`int (ent_next)(struct fat_entry );`
18			`};`
19
20			`static DEFINE_SPINLOCK(fat12_entry_lock);`
21
22			`static void fat12_ent_blocknr(struct super_block *sb, int entry,`
23			`int offset, sector_t blocknr)`
24			`{`
25			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
26			`int bytes = entry + (entry >> 1);`
27			`WARN_ON(entry < FAT_START_ENT \|\| sbi->max_cluster <= entry);`
28			`*offset = bytes & (sb->s_blocksize - 1);`
29			`*blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);`
30			`}`
31
32			`static void fat_ent_blocknr(struct super_block *sb, int entry,`
33			`int offset, sector_t blocknr)`
34			`{`
35			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
36			`int bytes = (entry << sbi->fatent_shift);`
37			`WARN_ON(entry < FAT_START_ENT \|\| sbi->max_cluster <= entry);`
38			`*offset = bytes & (sb->s_blocksize - 1);`
39			`*blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);`
40			`}`
41
42			`static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset)`
43			`{`
44			`struct buffer_head **bhs = fatent->bhs;`
45			`if (fatent->nr_bhs == 1) {`
46			`WARN_ON(offset >= (bhs[0]->b_size - 1));`
47			`fatent->u.ent12_p[0] = bhs[0]->b_data + offset;`
48			`fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1);`
49			`} else {`
50			`WARN_ON(offset != (bhs[0]->b_size - 1));`
51			`fatent->u.ent12_p[0] = bhs[0]->b_data + offset;`
52			`fatent->u.ent12_p[1] = bhs[1]->b_data;`
53			`}`
54			`}`
55
56			`static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset)`
57			`{`
58			`WARN_ON(offset & (2 - 1));`
59			`fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset);`
60			`}`
61
62			`static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset)`
63			`{`
64			`WARN_ON(offset & (4 - 1));`
65			`fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset);`
66			`}`
67
68			`static int fat12_ent_bread(struct super_block sb, struct fat_entry fatent,`
69			`int offset, sector_t blocknr)`
70			`{`
71			`struct buffer_head **bhs = fatent->bhs;`
72
73			`WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);`
74			`bhs[0] = sb_bread(sb, blocknr);`
75			`if (!bhs[0])`
76			`goto err;`
77
78			`if ((offset + 1) < sb->s_blocksize)`
79			`fatent->nr_bhs = 1;`
80			`else {`
81			`/* This entry is block boundary, it needs the next block */`
82			`blocknr++;`
83			`bhs[1] = sb_bread(sb, blocknr);`
84			`if (!bhs[1])`
85			`goto err_brelse;`
86			`fatent->nr_bhs = 2;`
87			`}`
88			`fat12_ent_set_ptr(fatent, offset);`
89			`return 0;`
90
91			`err_brelse:`
92			`brelse(bhs[0]);`
93			`err:`
94			`printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n",`
95			`(unsigned long long)blocknr);`
96			`return -EIO;`
97			`}`
98
99			`static int fat_ent_bread(struct super_block sb, struct fat_entry fatent,`
100			`int offset, sector_t blocknr)`
101			`{`
102			`struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;`
103
104			`WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);`
105			`fatent->bhs[0] = sb_bread(sb, blocknr);`
106			`if (!fatent->bhs[0]) {`
107			`printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n",`
108			`(unsigned long long)blocknr);`
109			`return -EIO;`
110			`}`
111			`fatent->nr_bhs = 1;`
112			`ops->ent_set_ptr(fatent, offset);`
113			`return 0;`
114			`}`
115
116			`static int fat12_ent_get(struct fat_entry *fatent)`
117			`{`
118			`u8 **ent12_p = fatent->u.ent12_p;`
119			`int next;`
120
121			`spin_lock(&fat12_entry_lock);`
122			`if (fatent->entry & 1)`
123			`next = (ent12_p[0] >> 4) \| (ent12_p[1] << 4);`
124			`else`
125			`next = (ent12_p[1] << 8) \| ent12_p[0];`
126			`spin_unlock(&fat12_entry_lock);`
127
128			`next &= 0x0fff;`
129			`if (next >= BAD_FAT12)`
130			`next = FAT_ENT_EOF;`
131			`return next;`
132			`}`
133
134			`static int fat16_ent_get(struct fat_entry *fatent)`
135			`{`
136			`int next = le16_to_cpu(*fatent->u.ent16_p);`
137			`WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1));`
138			`if (next >= BAD_FAT16)`
139			`next = FAT_ENT_EOF;`
140			`return next;`
141			`}`
142
143			`static int fat32_ent_get(struct fat_entry *fatent)`
144			`{`
145			`int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff;`
146			`WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1));`
147			`if (next >= BAD_FAT32)`
148			`next = FAT_ENT_EOF;`
149			`return next;`
150			`}`
151
152			`static void fat12_ent_put(struct fat_entry *fatent, int new)`
153			`{`
154			`u8 **ent12_p = fatent->u.ent12_p;`
155
156			`if (new == FAT_ENT_EOF)`
157			`new = EOF_FAT12;`
158
159			`spin_lock(&fat12_entry_lock);`
160			`if (fatent->entry & 1) {`
161			`ent12_p[0] = (new << 4) \| (ent12_p[0] & 0x0f);`
162			`*ent12_p[1] = new >> 4;`
163			`} else {`
164			`*ent12_p[0] = new & 0xff;`
165			`ent12_p[1] = (ent12_p[1] & 0xf0) \| (new >> 8);`
166			`}`
167			`spin_unlock(&fat12_entry_lock);`
168
169			`mark_buffer_dirty(fatent->bhs[0]);`
170			`if (fatent->nr_bhs == 2)`
171			`mark_buffer_dirty(fatent->bhs[1]);`
172			`}`
173
174			`static void fat16_ent_put(struct fat_entry *fatent, int new)`
175			`{`
176			`if (new == FAT_ENT_EOF)`
177			`new = EOF_FAT16;`
178
179			`*fatent->u.ent16_p = cpu_to_le16(new);`
180			`mark_buffer_dirty(fatent->bhs[0]);`
181			`}`
182
183			`static void fat32_ent_put(struct fat_entry *fatent, int new)`
184			`{`
185			`if (new == FAT_ENT_EOF)`
186			`new = EOF_FAT32;`
187
188			`WARN_ON(new & 0xf0000000);`
189			`new \|= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff;`
190			`*fatent->u.ent32_p = cpu_to_le32(new);`
191			`mark_buffer_dirty(fatent->bhs[0]);`
192			`}`
193
194			`static int fat12_ent_next(struct fat_entry *fatent)`
195			`{`
196			`u8 **ent12_p = fatent->u.ent12_p;`
197			`struct buffer_head **bhs = fatent->bhs;`
198			`u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1);`
199
200			`fatent->entry++;`
201			`if (fatent->nr_bhs == 1) {`
202			`WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 2)));`
203			`WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));`
204			`if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) {`
205			`ent12_p[0] = nextp - 1;`
206			`ent12_p[1] = nextp;`
207			`return 1;`
208			`}`
209			`} else {`
210			`WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));`
211			`WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data);`
212			`ent12_p[0] = nextp - 1;`
213			`ent12_p[1] = nextp;`
214			`brelse(bhs[0]);`
215			`bhs[0] = bhs[1];`
216			`fatent->nr_bhs = 1;`
217			`return 1;`
218			`}`
219			`ent12_p[0] = NULL;`
220			`ent12_p[1] = NULL;`
221			`return 0;`
222			`}`
223
224			`static int fat16_ent_next(struct fat_entry *fatent)`
225			`{`
226			`const struct buffer_head *bh = fatent->bhs[0];`
227			`fatent->entry++;`
228			`if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) {`
229			`fatent->u.ent16_p++;`
230			`return 1;`
231			`}`
232			`fatent->u.ent16_p = NULL;`
233			`return 0;`
234			`}`
235
236			`static int fat32_ent_next(struct fat_entry *fatent)`
237			`{`
238			`const struct buffer_head *bh = fatent->bhs[0];`
239			`fatent->entry++;`
240			`if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) {`
241			`fatent->u.ent32_p++;`
242			`return 1;`
243			`}`
244			`fatent->u.ent32_p = NULL;`
245			`return 0;`
246			`}`
247
248			`static struct fatent_operations fat12_ops = {`
249			`.ent_blocknr = fat12_ent_blocknr,`
250			`.ent_set_ptr = fat12_ent_set_ptr,`
251			`.ent_bread = fat12_ent_bread,`
252			`.ent_get = fat12_ent_get,`
253			`.ent_put = fat12_ent_put,`
254			`.ent_next = fat12_ent_next,`
255			`};`
256
257			`static struct fatent_operations fat16_ops = {`
258			`.ent_blocknr = fat_ent_blocknr,`
259			`.ent_set_ptr = fat16_ent_set_ptr,`
260			`.ent_bread = fat_ent_bread,`
261			`.ent_get = fat16_ent_get,`
262			`.ent_put = fat16_ent_put,`
263			`.ent_next = fat16_ent_next,`
264			`};`
265
266			`static struct fatent_operations fat32_ops = {`
267			`.ent_blocknr = fat_ent_blocknr,`
268			`.ent_set_ptr = fat32_ent_set_ptr,`
269			`.ent_bread = fat_ent_bread,`
270			`.ent_get = fat32_ent_get,`
271			`.ent_put = fat32_ent_put,`
272			`.ent_next = fat32_ent_next,`
273			`};`
274
275			`static inline void lock_fat(struct msdos_sb_info *sbi)`
276			`{`
277			`mutex_lock(&sbi->fat_lock);`
278			`}`
279
280			`static inline void unlock_fat(struct msdos_sb_info *sbi)`
281			`{`
282			`mutex_unlock(&sbi->fat_lock);`
283			`}`
284
285			`void fat_ent_access_init(struct super_block *sb)`
286			`{`
287			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
288
289			`mutex_init(&sbi->fat_lock);`
290
291			`switch (sbi->fat_bits) {`
292			`case 32:`
293			`sbi->fatent_shift = 2;`
294			`sbi->fatent_ops = &fat32_ops;`
295			`break;`
296			`case 16:`
297			`sbi->fatent_shift = 1;`
298			`sbi->fatent_ops = &fat16_ops;`
299			`break;`
300			`case 12:`
301			`sbi->fatent_shift = -1;`
302			`sbi->fatent_ops = &fat12_ops;`
303			`break;`
304			`}`
305			`}`
306
307			`static inline int fat_ent_update_ptr(struct super_block *sb,`
308			`struct fat_entry *fatent,`
309			`int offset, sector_t blocknr)`
310			`{`
311			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
312			`struct fatent_operations *ops = sbi->fatent_ops;`
313			`struct buffer_head **bhs = fatent->bhs;`
314
315			`/* Is this fatent's blocks including this entry? */`
316			`if (!fatent->nr_bhs \|\| bhs[0]->b_blocknr != blocknr)`
317			`return 0;`
318			`/* Does this entry need the next block? */`
319			`if (sbi->fat_bits == 12 && (offset + 1) >= sb->s_blocksize) {`
320			`if (fatent->nr_bhs != 2 \|\| bhs[1]->b_blocknr != (blocknr + 1))`
321			`return 0;`
322			`}`
323			`ops->ent_set_ptr(fatent, offset);`
324			`return 1;`
325			`}`
326
327			`int fat_ent_read(struct inode inode, struct fat_entry fatent, int entry)`
328			`{`
329			`struct super_block *sb = inode->i_sb;`
330			`struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);`
331			`struct fatent_operations *ops = sbi->fatent_ops;`
332			`int err, offset;`
333			`sector_t blocknr;`
334
335			`if (entry < FAT_START_ENT \|\| sbi->max_cluster <= entry) {`
336			`fatent_brelse(fatent);`
337			`fat_fs_panic(sb, "invalid access to FAT (entry 0x%08x)", entry);`
338			`return -EIO;`
339			`}`
340
341			`fatent_set_entry(fatent, entry);`
342			`ops->ent_blocknr(sb, entry, &offset, &blocknr);`
343
344			`if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) {`
345			`fatent_brelse(fatent);`
346			`err = ops->ent_bread(sb, fatent, offset, blocknr);`
347			`if (err)`
348			`return err;`
349			`}`
350			`return ops->ent_get(fatent);`
351			`}`
352
353			`/* FIXME: We can write the blocks as more big chunk. */`
354			`static int fat_mirror_bhs(struct super_block sb, struct buffer_head *bhs,`
355			`int nr_bhs)`
356			`{`
357			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
358			`struct buffer_head *c_bh;`
359			`int err, n, copy;`
360
361			`err = 0;`
362			`for (copy = 1; copy < sbi->fats; copy++) {`
363			`sector_t backup_fat = sbi->fat_length * copy;`
364
365			`for (n = 0; n < nr_bhs; n++) {`
366			`c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr);`
367			`if (!c_bh) {`
368			`err = -ENOMEM;`
369			`goto error;`
370			`}`
371			`memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize);`
372			`set_buffer_uptodate(c_bh);`
373			`mark_buffer_dirty(c_bh);`
374			`if (sb->s_flags & MS_SYNCHRONOUS)`
375			`err = sync_dirty_buffer(c_bh);`
376			`brelse(c_bh);`
377			`if (err)`
378			`goto error;`
379			`}`
380			`}`
381			`error:`
382			`return err;`
383			`}`
384
385			`int fat_ent_write(struct inode inode, struct fat_entry fatent,`
386			`int new, int wait)`
387			`{`
388			`struct super_block *sb = inode->i_sb;`
389			`struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;`
390			`int err;`
391
392			`ops->ent_put(fatent, new);`
393			`if (wait) {`
394			`err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs);`
395			`if (err)`
396			`return err;`
397			`}`
398			`return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs);`
399			`}`
400
401			`static inline int fat_ent_next(struct msdos_sb_info *sbi,`
402			`struct fat_entry *fatent)`
403			`{`
404			`if (sbi->fatent_ops->ent_next(fatent)) {`
405			`if (fatent->entry < sbi->max_cluster)`
406			`return 1;`
407			`}`
408			`return 0;`
409			`}`
410
411			`static inline int fat_ent_read_block(struct super_block *sb,`
412			`struct fat_entry *fatent)`
413			`{`
414			`struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;`
415			`sector_t blocknr;`
416			`int offset;`
417
418			`fatent_brelse(fatent);`
419			`ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);`
420			`return ops->ent_bread(sb, fatent, offset, blocknr);`
421			`}`
422
423			`static void fat_collect_bhs(struct buffer_head *bhs, int nr_bhs,`
424			`struct fat_entry *fatent)`
425			`{`
426			`int n, i;`
427
428			`for (n = 0; n < fatent->nr_bhs; n++) {`
429			`for (i = 0; i < *nr_bhs; i++) {`
430			`if (fatent->bhs[n] == bhs[i])`
431			`break;`
432			`}`
433			`if (i == *nr_bhs) {`
434			`get_bh(fatent->bhs[n]);`
435			`bhs[i] = fatent->bhs[n];`
436			`(*nr_bhs)++;`
437			`}`
438			`}`
439			`}`
440
441			`int fat_alloc_clusters(struct inode inode, int cluster, int nr_cluster)`
442			`{`
443			`struct super_block *sb = inode->i_sb;`
444			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
445			`struct fatent_operations *ops = sbi->fatent_ops;`
446			`struct fat_entry fatent, prev_ent;`
447			`struct buffer_head *bhs[MAX_BUF_PER_PAGE];`
448			`int i, count, err, nr_bhs, idx_clus;`
449
450			`BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */`
451
452			`lock_fat(sbi);`
453			`if (sbi->free_clusters != -1 && sbi->free_clusters < nr_cluster) {`
454			`unlock_fat(sbi);`
455			`return -ENOSPC;`
456			`}`
457
458			`err = nr_bhs = idx_clus = 0;`
459			`count = FAT_START_ENT;`
460			`fatent_init(&prev_ent);`
461			`fatent_init(&fatent);`
462			`fatent_set_entry(&fatent, sbi->prev_free + 1);`
463			`while (count < sbi->max_cluster) {`
464			`if (fatent.entry >= sbi->max_cluster)`
465			`fatent.entry = FAT_START_ENT;`
466			`fatent_set_entry(&fatent, fatent.entry);`
467			`err = fat_ent_read_block(sb, &fatent);`
468			`if (err)`
469			`goto out;`
470
471			`/* Find the free entries in a block */`
472			`do {`
473			`if (ops->ent_get(&fatent) == FAT_ENT_FREE) {`
474			`int entry = fatent.entry;`
475
476			`/* make the cluster chain */`
477			`ops->ent_put(&fatent, FAT_ENT_EOF);`
478			`if (prev_ent.nr_bhs)`
479			`ops->ent_put(&prev_ent, entry);`
480
481			`fat_collect_bhs(bhs, &nr_bhs, &fatent);`
482
483			`sbi->prev_free = entry;`
484			`if (sbi->free_clusters != -1)`
485			`sbi->free_clusters--;`
486			`sb->s_dirt = 1;`
487
488			`cluster[idx_clus] = entry;`
489			`idx_clus++;`
490			`if (idx_clus == nr_cluster)`
491			`goto out;`
492
493			`/*`
494			`* fat_collect_bhs() gets ref-count of bhs,`
495			`* so we can still use the prev_ent.`
496			`*/`
497			`prev_ent = fatent;`
498			`}`
499			`count++;`
500			`if (count == sbi->max_cluster)`
501			`break;`
502			`} while (fat_ent_next(sbi, &fatent));`
503			`}`
504
505			`/* Couldn't allocate the free entries */`
506			`sbi->free_clusters = 0;`
507			`sb->s_dirt = 1;`
508			`err = -ENOSPC;`
509
510			`out:`
511			`unlock_fat(sbi);`
512			`fatent_brelse(&fatent);`
513			`if (!err) {`
514			`if (inode_needs_sync(inode))`
515			`err = fat_sync_bhs(bhs, nr_bhs);`
516			`if (!err)`
517			`err = fat_mirror_bhs(sb, bhs, nr_bhs);`
518			`}`
519			`for (i = 0; i < nr_bhs; i++)`
520			`brelse(bhs[i]);`
521
522			`if (err && idx_clus)`
523			`fat_free_clusters(inode, cluster[0]);`
524
525			`return err;`
526			`}`
527
528			`int fat_free_clusters(struct inode *inode, int cluster)`
529			`{`
530			`struct super_block *sb = inode->i_sb;`
531			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
532			`struct fatent_operations *ops = sbi->fatent_ops;`
533			`struct fat_entry fatent;`
534			`struct buffer_head *bhs[MAX_BUF_PER_PAGE];`
535			`int i, err, nr_bhs;`
536
537			`nr_bhs = 0;`
538			`fatent_init(&fatent);`
539			`lock_fat(sbi);`
540			`do {`
541			`cluster = fat_ent_read(inode, &fatent, cluster);`
542			`if (cluster < 0) {`
543			`err = cluster;`
544			`goto error;`
545			`} else if (cluster == FAT_ENT_FREE) {`
546			`fat_fs_panic(sb, "%s: deleting FAT entry beyond EOF",`
547			`__FUNCTION__);`
548			`err = -EIO;`
549			`goto error;`
550			`}`
551
552			`ops->ent_put(&fatent, FAT_ENT_FREE);`
553			`if (sbi->free_clusters != -1) {`
554			`sbi->free_clusters++;`
555			`sb->s_dirt = 1;`
556			`}`
557
558			`if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) {`
559			`if (sb->s_flags & MS_SYNCHRONOUS) {`
560			`err = fat_sync_bhs(bhs, nr_bhs);`
561			`if (err)`
562			`goto error;`
563			`}`
564			`err = fat_mirror_bhs(sb, bhs, nr_bhs);`
565			`if (err)`
566			`goto error;`
567			`for (i = 0; i < nr_bhs; i++)`
568			`brelse(bhs[i]);`
569			`nr_bhs = 0;`
570			`}`
571			`fat_collect_bhs(bhs, &nr_bhs, &fatent);`
572			`} while (cluster != FAT_ENT_EOF);`
573
574			`if (sb->s_flags & MS_SYNCHRONOUS) {`
575			`err = fat_sync_bhs(bhs, nr_bhs);`
576			`if (err)`
577			`goto error;`
578			`}`
579			`err = fat_mirror_bhs(sb, bhs, nr_bhs);`
580			`error:`
581			`fatent_brelse(&fatent);`
582			`for (i = 0; i < nr_bhs; i++)`
583			`brelse(bhs[i]);`
584			`unlock_fat(sbi);`
585
586			`fat_clusters_flush(sb);`
587
588			`return err;`
589			`}`
590
591			`EXPORT_SYMBOL_GPL(fat_free_clusters);`
592
593			`/* 128kb is the whole sectors for FAT12 and FAT16 */`
594			`#define FAT_READA_SIZE (128 * 1024)`
595
596			`static void fat_ent_reada(struct super_block sb, struct fat_entry fatent,`
597			`unsigned long reada_blocks)`
598			`{`
599			`struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;`
600			`sector_t blocknr;`
601			`int i, offset;`
602
603			`ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);`
604
605			`for (i = 0; i < reada_blocks; i++)`
606			`sb_breadahead(sb, blocknr + i);`
607			`}`
608
609			`int fat_count_free_clusters(struct super_block *sb)`
610			`{`
611			`struct msdos_sb_info *sbi = MSDOS_SB(sb);`
612			`struct fatent_operations *ops = sbi->fatent_ops;`
613			`struct fat_entry fatent;`
614			`unsigned long reada_blocks, reada_mask, cur_block;`
615			`int err = 0, free;`
616
617			`lock_fat(sbi);`
618			`if (sbi->free_clusters != -1)`
619			`goto out;`
620
621			`reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;`
622			`reada_mask = reada_blocks - 1;`
623			`cur_block = 0;`
624
625			`free = 0;`
626			`fatent_init(&fatent);`
627			`fatent_set_entry(&fatent, FAT_START_ENT);`
628			`while (fatent.entry < sbi->max_cluster) {`
629			`/* readahead of fat blocks */`
630			`if ((cur_block & reada_mask) == 0) {`
631			`unsigned long rest = sbi->fat_length - cur_block;`
632			`fat_ent_reada(sb, &fatent, min(reada_blocks, rest));`
633			`}`
634			`cur_block++;`
635
636			`err = fat_ent_read_block(sb, &fatent);`
637			`if (err)`
638			`goto out;`
639
640			`do {`
641			`if (ops->ent_get(&fatent) == FAT_ENT_FREE)`
642			`free++;`
643			`} while (fat_ent_next(sbi, &fatent));`
644			`}`
645			`sbi->free_clusters = free;`
646			`sb->s_dirt = 1;`
647			`fatent_brelse(&fatent);`
648			`out:`
649			`unlock_fat(sbi);`
650			`return err;`
651			`}`