static int simplefs_create_fs_object(struct inode *dir, struct dentry *dentry,
umode_t mode)
{
struct inode *inode;
struct simplefs_inode *sfs_inode;
struct super_block *sb;
struct simplefs_inode *parent_dir_inode;
struct buffer_head *bh;
struct simplefs_dir_record *dir_contents_datablock;
uint64_t count;
int ret;
if (mutex_lock_interruptible(&simplefs_directory_children_update_lock)) {
sfs_trace("Failed to acquire mutex lock\n");
return -EINTR;
}
sb = dir->i_sb;
ret = simplefs_sb_get_objects_count(sb, &count);
if (ret < 0) {
mutex_unlock(&simplefs_directory_children_update_lock);
return ret;
}
if (unlikely(count >= SIMPLEFS_MAX_FILESYSTEM_OBJECTS_SUPPORTED)) {
/* The above condition can be just == insted of the >= */
printk(KERN_ERR
"Maximum number of objects supported by simplefs is already reached");
mutex_unlock(&simplefs_directory_children_update_lock);
return -ENOSPC;
}
if (!S_ISDIR(mode) && !S_ISREG(mode)) {
printk(KERN_ERR
"Creation request but for neither a file nor a directory");
mutex_unlock(&simplefs_directory_children_update_lock);
return -EINVAL;
}
inode = new_inode(sb);
if (!inode) {
mutex_unlock(&simplefs_directory_children_update_lock);
return -ENOMEM;
}
inode->i_sb = sb;
inode->i_op = &simplefs_inode_ops;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
inode->i_ino = (count + SIMPLEFS_START_INO - SIMPLEFS_RESERVED_INODES + 1);
sfs_inode = kmem_cache_alloc(sfs_inode_cachep, GFP_KERNEL);
sfs_inode->inode_no = inode->i_ino;
inode->i_private = sfs_inode;
sfs_inode->mode = mode;
if (S_ISDIR(mode)) {
printk(KERN_INFO "New directory creation request\n");
sfs_inode->dir_children_count = 0;
inode->i_fop = &simplefs_dir_operations;
} else if (S_ISREG(mode)) {
printk(KERN_INFO "New file creation request\n");
sfs_inode->file_size = 0;
inode->i_fop = &simplefs_file_operations;
}
/* First get a free block and update the free map,
* Then add inode to the inode store and update the sb inodes_count,
* Then update the parent directory's inode with the new child.
*
* The above ordering helps us to maintain fs consistency
* even in most crashes
*/
ret = simplefs_sb_get_a_freeblock(sb, &sfs_inode->data_block_number);
if (ret < 0) {
printk(KERN_ERR "simplefs could not get a freeblock");
mutex_unlock(&simplefs_directory_children_update_lock);
return ret;
}
simplefs_inode_add(sb, sfs_inode);
parent_dir_inode = SIMPLEFS_INODE(dir);
bh = sb_bread(sb, parent_dir_inode->data_block_number);
BUG_ON(!bh);
dir_contents_datablock = (struct simplefs_dir_record *)bh->b_data;
/* Navigate to the last record in the directory contents */
dir_contents_datablock += parent_dir_inode->dir_children_count;
dir_contents_datablock->inode_no = sfs_inode->inode_no;
strcpy(dir_contents_datablock->filename, dentry->d_name.name);
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
brelse(bh);
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
mutex_unlock(&simplefs_directory_children_update_lock);
sfs_trace("Failed to acquire mutex lock\n");
return -EINTR;
}
parent_dir_inode->dir_children_count++;
ret = simplefs_inode_save(sb, parent_dir_inode);
if (ret) {
mutex_unlock(&simplefs_inodes_mgmt_lock);
mutex_unlock(&simplefs_directory_children_update_lock);
/* TODO: Remove the newly created inode from the disk and in-memory inode store
* and also update the superblock, freemaps etc. to reflect the same.
* Basically, Undo all actions done during this create call */
return ret;
}
mutex_unlock(&simplefs_inodes_mgmt_lock);
mutex_unlock(&simplefs_directory_children_update_lock);
inode_init_owner(inode, dir, mode);
d_add(dentry, inode);
return 0;
}
static int simplefs_create_fs_object(struct inode *dir, struct dentry *dentry,
umode_t mode)
{
struct inode *inode;
struct simplefs_inode *sfs_inode;
struct simplefs_inode *inode_iterator;
struct super_block *sb;
struct simplefs_dir_record *record;
struct simplefs_inode *parent_dir_inode;
struct buffer_head *bh;
struct simplefs_dir_record *dir_contents_datablock;
uint64_t count;
int ret;
if (mutex_lock_interruptible(&simplefs_directory_children_update_lock)) {
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
return -EINTR;
}
sb = dir->i_sb;
ret = simplefs_sb_get_objects_count(sb, &count);
if (ret < 0) {
mutex_unlock(&simplefs_directory_children_update_lock);
return ret;
}
if (unlikely(count >= SIMPLEFS_MAX_FILESYSTEM_OBJECTS_SUPPORTED)) {
/* The above condition can be just == insted of the >= */
printk(KERN_ERR
"Maximum number of objects supported by simplefs is already reached");
mutex_unlock(&simplefs_directory_children_update_lock);
return -ENOSPC;
}
if (!S_ISDIR(mode) && !S_ISREG(mode)) {
printk(KERN_ERR
"Creation request but for neither a file nor a directory");
mutex_unlock(&simplefs_directory_children_update_lock);
return -EINVAL;
}
inode = new_inode(sb);
if (!inode) {
mutex_unlock(&simplefs_directory_children_update_lock);
return -ENOMEM;
}
inode->i_sb = sb;
inode->i_op = &simplefs_inode_ops;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
inode->i_ino = 10;
/* Loop until we get an unique inode number */
while (simplefs_get_inode(sb, inode->i_ino)) {
/* inode inode->i_ino already exists */
inode->i_ino++;
}
/* FIXME: This is leaking. We need to free all in-memory inodes sometime */
sfs_inode = kmalloc(sizeof(struct simplefs_inode), GFP_KERNEL);
sfs_inode->inode_no = inode->i_ino;
inode->i_private = sfs_inode;
sfs_inode->mode = mode;
if (S_ISDIR(mode)) {
printk(KERN_INFO "New directory creation request\n");
sfs_inode->dir_children_count = 0;
inode->i_fop = &simplefs_dir_operations;
} else if (S_ISREG(mode)) {
printk(KERN_INFO "New file creation request\n");
sfs_inode->file_size = 0;
inode->i_fop = &simplefs_file_operations;
}
/* First get a free block and update the free map,
* Then add inode to the inode store and update the sb inodes_count,
* Then update the parent directory's inode with the new child.
*
* The above ordering helps us to maintain fs consistency
* even in most crashes
*/
ret = simplefs_sb_get_a_freeblock(sb, &sfs_inode->data_block_number);
if (ret < 0) {
printk(KERN_ERR "simplefs could not get a freeblock");
mutex_unlock(&simplefs_directory_children_update_lock);
return ret;
}
simplefs_inode_add(sb, sfs_inode);
record = kmalloc(sizeof(struct simplefs_dir_record), GFP_KERNEL);
record->inode_no = sfs_inode->inode_no;
strcpy(record->filename, dentry->d_name.name);
parent_dir_inode = SIMPLEFS_INODE(dir);
bh = sb_bread(sb, parent_dir_inode->data_block_number);
dir_contents_datablock = (struct simplefs_dir_record *)bh->b_data;
/* Navigate to the last record in the directory contents */
dir_contents_datablock += parent_dir_inode->dir_children_count;
memcpy(dir_contents_datablock, record,
sizeof(struct simplefs_dir_record));
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
brelse(bh);
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
mutex_unlock(&simplefs_directory_children_update_lock);
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
return -EINTR;
}
bh = (struct buffer_head *)sb_bread(sb,
SIMPLEFS_INODESTORE_BLOCK_NUMBER);
inode_iterator = (struct simplefs_inode *)bh->b_data;
if (mutex_lock_interruptible(&simplefs_sb_lock)) {
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
return -EINTR;
}
count = 0;
while (inode_iterator->inode_no != parent_dir_inode->inode_no
&& count < SIMPLEFS_SB(sb)->inodes_count) {
count++;
inode_iterator++;
}
if (likely(inode_iterator->inode_no == parent_dir_inode->inode_no)) {
parent_dir_inode->dir_children_count++;
inode_iterator->dir_children_count =
parent_dir_inode->dir_children_count;
/* Updated the parent inode's dir count to reflect the new child too */
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
} else {
printk(KERN_ERR
"The updated childcount could not be stored to the dir inode.");
/* TODO: Remove the newly created inode from the disk and in-memory inode store
* and also update the superblock, freemaps etc. to reflect the same.
* Basically, Undo all actions done during this create call */
}
brelse(bh);
mutex_unlock(&simplefs_sb_lock);
mutex_unlock(&simplefs_inodes_mgmt_lock);
mutex_unlock(&simplefs_directory_children_update_lock);
inode_init_owner(inode, dir, mode);
d_add(dentry, inode);
return 0;
}
