static long fat_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
{
int err = 0;
struct inode *inode = file->f_mapping->host;
int cluster, nr_cluster, fclus, dclus, free_bytes, nr_bytes;
struct super_block *sb = inode->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
if (mode & ~FALLOC_FL_KEEP_SIZE)
return -EOPNOTSUPP;
if ((offset + len) <= MSDOS_I(inode)->mmu_private) {
fat_msg(sb, KERN_ERR,
"fat_fallocate():Blocks already allocated");
return -EINVAL;
}
if ((mode & FALLOC_FL_KEEP_SIZE)) {
if (inode->i_size > 0) {
err = fat_get_cluster(inode, FAT_ENT_EOF,
&fclus, &dclus);
if (err < 0) {
fat_msg(sb, KERN_ERR,
"fat_fallocate():fat_get_cluster() error");
return err;
}
free_bytes = ((fclus+1) << sbi->cluster_bits) -
(inode->i_size);
nr_bytes = (offset + len - inode->i_size) - free_bytes;
} else
nr_bytes = (offset + len - inode->i_size);
nr_cluster = (nr_bytes + (sbi->cluster_size - 1)) >>
sbi->cluster_bits;
mutex_lock(&inode->i_mutex);
while (nr_cluster-- > 0) {
err = fat_alloc_clusters(inode, &cluster, 1);
if (err) {
fat_msg(sb, KERN_ERR,
"fat_fallocate():fat_alloc_clusters() error");
goto error;
}
err = fat_chain_add(inode, cluster, 1);
if (err) {
fat_free_clusters(inode, cluster);
goto error;
}
}
err = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
if (err < 0) {
fat_msg(sb, KERN_ERR,
"fat_fallocate():fat_get_cluster() error");
goto error;
}
MSDOS_I(inode)->mmu_private = (fclus + 1) << sbi->cluster_bits;
} else {
/*
* Desc: Return the size of a directory file in bytes
*
*/
static int fat_calc_dir_size(struct inode *inode)
{
struct fat_sb_info *sbi = MSDOS_SB(inode->i_sb);
int ret, fclus, dclus;
inode->i_size = 0;
if (MSDOS_I(inode)->i_start == 0)
return 0;
ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
if (ret < 0)
return ret;
inode->i_size = (fclus + 1) << sbi->cluster_bits;
return 0;
}
/** Walk the cluster chain.
*
* @param bs Buffer holding the boot sector for the file.
* @param service_id Service ID of the device with the file.
* @param firstc First cluster to start the walk with.
* @param lastc If non-NULL, output argument hodling the last cluster
* number visited.
* @param numc If non-NULL, output argument holding the number of
* clusters seen during the walk.
* @param max_clusters Maximum number of clusters to visit.
*
* @return EOK on success or a negative error code.
*/
int
fat_cluster_walk(fat_bs_t *bs, service_id_t service_id, fat_cluster_t firstc,
fat_cluster_t *lastc, uint32_t *numc, uint32_t max_clusters)
{
uint32_t clusters = 0;
fat_cluster_t clst = firstc, clst_last1 = FAT_CLST_LAST1(bs);
fat_cluster_t clst_bad = FAT_CLST_BAD(bs);
int rc;
if (firstc == FAT_CLST_RES0) {
/* No space allocated to the file. */
if (lastc)
*lastc = firstc;
if (numc)
*numc = 0;
return EOK;
}
while (clst < clst_last1 && clusters < max_clusters) {
assert(clst >= FAT_CLST_FIRST);
if (lastc)
*lastc = clst; /* remember the last cluster number */
/* read FAT1 */
rc = fat_get_cluster(bs, service_id, FAT1, clst, &clst);
if (rc != EOK)
return rc;
assert(clst != clst_bad);
clusters++;
}
if (lastc && clst < clst_last1)
*lastc = clst;
if (numc)
*numc = clusters;
return EOK;
}
/* Free all clusters after the skip'th cluster. */
static int fat_free(struct inode *inode, int skip)
{
struct super_block *sb = inode->i_sb;
int err, wait, free_start, i_start, i_logstart;
if (MSDOS_I(inode)->i_start == 0)
return 0;
fat_cache_inval_inode(inode);
wait = IS_DIRSYNC(inode);
i_start = free_start = MSDOS_I(inode)->i_start;
i_logstart = MSDOS_I(inode)->i_logstart;
/* First, we write the new file size. */
if (!skip) {
MSDOS_I(inode)->i_start = 0;
MSDOS_I(inode)->i_logstart = 0;
}
MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
if (wait) {
err = fat_sync_inode(inode);
if (err) {
MSDOS_I(inode)->i_start = i_start;
MSDOS_I(inode)->i_logstart = i_logstart;
return err;
}
} else
mark_inode_dirty(inode);
/* Write a new EOF, and get the remaining cluster chain for freeing. */
if (skip) {
struct fat_entry fatent;
int ret, fclus, dclus;
ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
if (ret < 0)
return ret;
else if (ret == FAT_ENT_EOF)
return 0;
fatent_init(&fatent);
ret = fat_ent_read(inode, &fatent, dclus);
if (ret == FAT_ENT_EOF) {
fatent_brelse(&fatent);
return 0;
} else if (ret == FAT_ENT_FREE) {
fat_fs_panic(sb,
"%s: invalid cluster chain (i_pos %lld)",
__FUNCTION__, MSDOS_I(inode)->i_pos);
ret = -EIO;
} else if (ret > 0) {
err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
if (err)
ret = err;
}
fatent_brelse(&fatent);
if (ret < 0)
return ret;
free_start = ret;
}
inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
/* Freeing the remained cluster chain */
return fat_free_clusters(inode, free_start);
}
