static void simplefs_put_super(struct super_block *sb)
{
struct simplefs_super_block *sfs_sb = SIMPLEFS_SB(sb);
if (sfs_sb->journal)
WARN_ON(jbd2_journal_destroy(sfs_sb->journal) < 0);
sfs_sb->journal = NULL;
}
void simplefs_inode_add(struct super_block *vsb, struct simplefs_inode *inode)
{
struct simplefs_super_block *sb = SIMPLEFS_SB(vsb);
struct buffer_head *bh;
struct simplefs_inode *inode_iterator;
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
sfs_trace("Failed to acquire mutex lock\n");
return;
}
bh = sb_bread(vsb, SIMPLEFS_INODESTORE_BLOCK_NUMBER);
BUG_ON(!bh);
inode_iterator = (struct simplefs_inode *)bh->b_data;
if (mutex_lock_interruptible(&simplefs_sb_lock)) {
sfs_trace("Failed to acquire mutex lock\n");
return;
}
/* Append the new inode in the end in the inode store */
inode_iterator += sb->inodes_count;
memcpy(inode_iterator, inode, sizeof(struct simplefs_inode));
sb->inodes_count++;
mark_buffer_dirty(bh);
simplefs_sb_sync(vsb);
brelse(bh);
mutex_unlock(&simplefs_sb_lock);
mutex_unlock(&simplefs_inodes_mgmt_lock);
}
static int simplefs_load_journal(struct super_block *sb, int devnum)
{
struct journal_s *journal;
char b[BDEVNAME_SIZE];
dev_t dev;
struct block_device *bdev;
int hblock, blocksize, len;
struct simplefs_super_block *sfs_sb = SIMPLEFS_SB(sb);
dev = new_decode_dev(devnum);
printk(KERN_INFO "Journal device is: %s\n", __bdevname(dev, b));
bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
if (IS_ERR(bdev))
return 1;
blocksize = sb->s_blocksize;
hblock = bdev_logical_block_size(bdev);
len = SIMPLEFS_MAX_FILESYSTEM_OBJECTS_SUPPORTED;
journal = jbd2_journal_init_dev(bdev, sb->s_bdev, 1, -1, blocksize);
if (!journal) {
printk(KERN_ERR "Can't load journal\n");
return 1;
}
journal->j_private = sb;
sfs_sb->journal = journal;
return 0;
}
/* This functions returns a simplefs_inode with the given inode_no
* from the inode store, if it exists. */
struct simplefs_inode *simplefs_get_inode(struct super_block *sb,
uint64_t inode_no)
{
struct simplefs_super_block *sfs_sb = SIMPLEFS_SB(sb);
struct simplefs_inode *sfs_inode = NULL;
int i;
struct buffer_head *bh;
/* The inode store can be read once and kept in memory permanently while mounting.
* But such a model will not be scalable in a filesystem with
* millions or billions of files (inodes) */
bh = (struct buffer_head *)sb_bread(sb,
SIMPLEFS_INODESTORE_BLOCK_NUMBER);
sfs_inode = (struct simplefs_inode *)bh->b_data;
#if 0
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
return NULL;
}
#endif
for (i = 0; i < sfs_sb->inodes_count; i++) {
if (sfs_inode->inode_no == inode_no) {
/* FIXME: bh->b_data is probably leaking */
return sfs_inode;
}
sfs_inode++;
}
// mutex_unlock(&simplefs_inodes_mgmt_lock);
return NULL;
}
static void simplefs_put_super(struct super_block *sb)
{
struct simple_fs_sb_i *msblk = SIMPLEFS_SB(sb);
if(msblk->inode_cachep)
kmem_cache_destroy(msblk->inode_cachep);
kfree(msblk);
sb->s_private = NULL;
}
static struct inode* simplefs_alloc_inode(struct super_block *sb)
{
struct simple_fs_sb_i *msblk = SIMPLEFS_SB(sb);
struct simple_fs_inode_i *inode =
kmem_cache_alloc(msblk->inode_cachep,GFP_KERNEL);
if(!inode)
return NULL;
return &inode->vfs_inode;
}
void simplefs_sync_metadata(struct super_block *sb)
{
struct simple_fs_sb_i *msblk = SIMPLEFS_SB(sb);
/*
* Start with inodes.
*/
simplefs_sync_metadata_buffer(msblk->inode_table);
simplefs_sync_metadata_buffer(msblk->inode_bitmap);
simeplfs_sync_metadata_buffer(msblk->block_bitmap);
}
static void simplefs_destroy_inode(struct inode *vfs_inode)
{
struct simple_fs_inode_i *inode = SIMPLEFS_INODE(vfs_inode);
struct simple_fs_sb_i *sb = SIMPLEFS_SB(vfs_inode->i_sb);
if (inode->indirect_block) {
if(!buffer_uptodate(inode->indirect_block))
sync_dirty_buffer(inode->indirect_block);
bforget(inode->indirect_block);
}
kmem_cache_free(sb->inode_cachep,inode);
}
void simplefs_sb_sync(struct super_block *vsb)
{
struct buffer_head *bh;
struct simplefs_super_block *sb = SIMPLEFS_SB(vsb);
bh = (struct buffer_head *)sb_bread(vsb,
SIMPLEFS_SUPERBLOCK_BLOCK_NUMBER);
bh->b_data = (char *)sb;
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
brelse(bh);
}
static int simplefs_sb_get_objects_count(struct super_block *vsb,
uint64_t * out)
{
struct simplefs_super_block *sb = SIMPLEFS_SB(vsb);
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
sfs_trace("Failed to acquire mutex lock\n");
return -EINTR;
}
*out = sb->inodes_count;
mutex_unlock(&simplefs_inodes_mgmt_lock);
return 0;
}
static int simplefs_sb_get_objects_count(struct super_block *vsb,
uint64_t * out)
{
struct simplefs_super_block *sb = SIMPLEFS_SB(vsb);
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
return -EINTR;
}
*out = sb->inodes_count;
mutex_unlock(&simplefs_inodes_mgmt_lock);
return 0;
}
static int simplefs_sb_load_journal(struct super_block *sb, struct inode *inode)
{
struct journal_s *journal;
struct simplefs_super_block *sfs_sb = SIMPLEFS_SB(sb);
journal = jbd2_journal_init_inode(inode);
if (!journal) {
printk(KERN_ERR "Can't load journal\n");
return 1;
}
journal->j_private = sb;
sfs_sb->journal = journal;
return 0;
}
struct simplefs_inode *simplefs_inode_search(struct super_block *sb,
struct simplefs_inode *start,
struct simplefs_inode *search)
{
uint64_t count = 0;
while (start->inode_no != search->inode_no
&& count < SIMPLEFS_SB(sb)->inodes_count) {
count++;
start++;
}
if (start->inode_no == search->inode_no) {
return start;
}
return NULL;
}
/* This functions returns a simplefs_inode with the given inode_no
* from the inode store, if it exists. */
struct simplefs_inode *simplefs_get_inode(struct super_block *sb,
uint64_t inode_no)
{
struct simplefs_super_block *sfs_sb = SIMPLEFS_SB(sb);
struct simplefs_inode *sfs_inode = NULL;
struct simplefs_inode *inode_buffer = NULL;
int i;
struct buffer_head *bh;
/* The inode store can be read once and kept in memory permanently while mounting.
* But such a model will not be scalable in a filesystem with
* millions or billions of files (inodes) */
bh = sb_bread(sb, SIMPLEFS_INODESTORE_BLOCK_NUMBER);
BUG_ON(!bh);
sfs_inode = (struct simplefs_inode *)bh->b_data;
#if 0
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
return NULL;
}
#endif
for (i = 0; i < sfs_sb->inodes_count; i++) {
if (sfs_inode->inode_no == inode_no) {
inode_buffer = kmem_cache_alloc(sfs_inode_cachep, GFP_KERNEL);
memcpy(inode_buffer, sfs_inode, sizeof(*inode_buffer));
break;
}
sfs_inode++;
}
// mutex_unlock(&simplefs_inodes_mgmt_lock);
brelse(bh);
return inode_buffer;
}
/* This function returns a blocknumber which is free.
* The block will be removed from the freeblock list.
*
* In an ideal, production-ready filesystem, we will not be dealing with blocks,
* and instead we will be using extents
*
* If for some reason, the file creation/deletion failed, the block number
* will still be marked as non-free. You need fsck to fix this.*/
int simplefs_sb_get_a_freeblock(struct super_block *vsb, uint64_t * out)
{
struct simplefs_super_block *sb = SIMPLEFS_SB(vsb);
int i;
int ret = 0;
if (mutex_lock_interruptible(&simplefs_sb_lock)) {
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
ret = -EINTR;
goto end;
}
/* Loop until we find a free block. We start the loop from 3,
* as all prior blocks will always be in use */
for (i = 3; i < SIMPLEFS_MAX_FILESYSTEM_OBJECTS_SUPPORTED; i++) {
if (sb->free_blocks & (1 << i)) {
break;
}
}
if (unlikely(i == SIMPLEFS_MAX_FILESYSTEM_OBJECTS_SUPPORTED)) {
printk(KERN_ERR "No more free blocks available");
ret = -ENOSPC;
goto end;
}
*out = i;
/* Remove the identified block from the free list */
sb->free_blocks &= ~(1 << i);
simplefs_sb_sync(vsb);
end:
mutex_unlock(&simplefs_sb_lock);
return ret;
}
static int simplefs_write_inode(struct inode *vfs_inode, struct writeback_control *wbc)
{
/*
* We just need to write the inode here not it's pages.
*/
struct simple_fs_inode_i *minode = SIMPLEFS_INODE(vfs_inode);
struct simple_fs_sb_i *msblk = SIMPLEFS_SB(vfs_inode->i_sb);
int inodes_per_block = SIMPLEFS_INODE_SIZE/msblk->sb.block_size;
/*
* Find the inode table where we need to write this inode.
*/
struct buffer_head *inode_table = msblk->inode_table[(minode->inode.inode_no - 1)/inodes_per_block];
struct simplefs_inode *disk_inode =
(struct simplefs_inode*)(inode_table->b_data + (minode->inode.inode_no - 1) % inodes_per_block);
minode->inode.m_time = timespec_to_ns(vfs_inode.m_time);
minode->inode.m_time = cpu_to_le64(minode->inode.m_time);
if(!(vfs_inode->i_mode & S_IFDIR)) {
minode->inode.file_size = i_size_read(vfs_inode);
minode->inode.file_size = cpu_to_le64(minode->inode.file_size);
}
memcpy(disk_inode,&minode->inode,sizeof(struct simplefs_inode));
mark_buffer_dirty(inode_table);
if(wbc->sync_mode == WB_SYNC_ALL) {
SFSDBG("[SFS] Writeback control was to sync all in %s \n",__FUNCTION__);
sync_dirty_buffer(inode_table);
}
/*
* Perhaps we should sync dirty buffer here,
* but let's see how far we can go. The inode
* may actually not be written if we don't force
* sync and let the flush thread do it for us.
*/
SFSDBG("Not syncing in %s\n",__FUNCTION__);
}
/* FIXME: The write support is rudimentary. I have not figured out a way to do writes
* from particular offsets (even though I have written some untested code for this below) efficiently. */
ssize_t simplefs_write(struct file * filp, const char __user * buf, size_t len,
loff_t * ppos)
{
/* After the commit dd37978c5 in the upstream linux kernel,
* we can use just filp->f_inode instead of the
* f->f_path.dentry->d_inode redirection */
struct inode *inode;
struct simplefs_inode *sfs_inode;
struct simplefs_inode *inode_iterator;
struct buffer_head *bh;
struct super_block *sb;
char *buffer;
int count;
inode = filp->f_path.dentry->d_inode;
sfs_inode = SIMPLEFS_INODE(inode);
sb = inode->i_sb;
if (*ppos + len >= SIMPLEFS_DEFAULT_BLOCK_SIZE) {
printk(KERN_ERR "File size write will exceed a block");
return -ENOSPC;
}
bh = (struct buffer_head *)sb_bread(filp->f_path.dentry->d_inode->i_sb,
sfs_inode->data_block_number);
if (!bh) {
printk(KERN_ERR "Reading the block number [%llu] failed.",
sfs_inode->data_block_number);
return 0;
}
buffer = (char *)bh->b_data;
/* Move the pointer until the required byte offset */
buffer += *ppos;
if (copy_from_user(buffer, buf, len)) {
brelse(bh);
printk(KERN_ERR
"Error copying file contents from the userspace buffer to the kernel space\n");
return -EFAULT;
}
*ppos += len;
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
brelse(bh);
/* Set new size
* sfs_inode->file_size = max(sfs_inode->file_size, *ppos);
*
* FIXME: What to do if someone writes only some parts in between ?
* The above code will also fail in case a file is overwritten with
* a shorter buffer */
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
printk(KERN_ERR "Failed to acquire mutex lock %s +%d\n",
__FILE__, __LINE__);
return -EINTR;
}
/* Save the modified inode */
bh = (struct buffer_head *)sb_bread(sb,
SIMPLEFS_INODESTORE_BLOCK_NUMBER);
sfs_inode->file_size = *ppos;
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 != sfs_inode->inode_no
&& count < SIMPLEFS_SB(sb)->inodes_count) {
count++;
inode_iterator++;
}
if (likely(count < SIMPLEFS_SB(sb)->inodes_count)) {
inode_iterator->file_size = sfs_inode->file_size;
printk(KERN_INFO
"The new filesize that is written is: [%llu] and len was: [%lu]\n",
sfs_inode->file_size, len);
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
} else {
printk(KERN_ERR
"The new filesize could not be stored to the inode.");
len = -EIO;
}
brelse(bh);
mutex_unlock(&simplefs_sb_lock);
mutex_unlock(&simplefs_inodes_mgmt_lock);
return len;
}
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;
}
/* FIXME: The write support is rudimentary. I have not figured out a way to do writes
* from particular offsets (even though I have written some untested code for this below) efficiently. */
ssize_t simplefs_write(struct file * filp, const char __user * buf, size_t len,
loff_t * ppos)
{
/* After the commit dd37978c5 in the upstream linux kernel,
* we can use just filp->f_inode instead of the
* f->f_path.dentry->d_inode redirection */
struct inode *inode;
struct simplefs_inode *sfs_inode;
struct buffer_head *bh;
struct super_block *sb;
struct simplefs_super_block *sfs_sb;
handle_t *handle;
char *buffer;
int retval;
sb = filp->f_path.dentry->d_inode->i_sb;
sfs_sb = SIMPLEFS_SB(sb);
handle = jbd2_journal_start(sfs_sb->journal, 1);
if (IS_ERR(handle))
return PTR_ERR(handle);
retval = generic_write_checks(filp, ppos, &len, 0);
if (retval)
return retval;
inode = filp->f_path.dentry->d_inode;
sfs_inode = SIMPLEFS_INODE(inode);
bh = sb_bread(filp->f_path.dentry->d_inode->i_sb,
sfs_inode->data_block_number);
if (!bh) {
printk(KERN_ERR "Reading the block number [%llu] failed.",
sfs_inode->data_block_number);
return 0;
}
buffer = (char *)bh->b_data;
/* Move the pointer until the required byte offset */
buffer += *ppos;
retval = jbd2_journal_get_write_access(handle, bh);
if (WARN_ON(retval)) {
brelse(bh);
sfs_trace("Can't get write access for bh\n");
return retval;
}
if (copy_from_user(buffer, buf, len)) {
brelse(bh);
printk(KERN_ERR
"Error copying file contents from the userspace buffer to the kernel space\n");
return -EFAULT;
}
*ppos += len;
retval = jbd2_journal_dirty_metadata(handle, bh);
if (WARN_ON(retval)) {
brelse(bh);
return retval;
}
handle->h_sync = 1;
retval = jbd2_journal_stop(handle);
if (WARN_ON(retval)) {
brelse(bh);
return retval;
}
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
brelse(bh);
/* Set new size
* sfs_inode->file_size = max(sfs_inode->file_size, *ppos);
*
* FIXME: What to do if someone writes only some parts in between ?
* The above code will also fail in case a file is overwritten with
* a shorter buffer */
if (mutex_lock_interruptible(&simplefs_inodes_mgmt_lock)) {
sfs_trace("Failed to acquire mutex lock\n");
return -EINTR;
}
sfs_inode->file_size = *ppos;
retval = simplefs_inode_save(sb, sfs_inode);
if (retval) {
len = retval;
}
mutex_unlock(&simplefs_inodes_mgmt_lock);
return len;
}
static int simplefs_get_block(struct inode *vfs_inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
struct simple_fs_sb_i *msblk = SIMPLEFS_SB(vfs_inode->i_sb);
struct simple_fs_inode_i *minode = SIMPLEFS_INODE(vfs_inode);
uint64_t mapped_block = -1;
if(iblock > msblk->sb.block_size/sizeof(uint64_t))
goto fail_get_block;
if(create) {
/* Do we already have allocated the indirect block.
* If yes then all we need to do is check the block location
* for being 0 within that.
*/
if(iblock) {
allocate_indirect_block:
if(minode->inode.indirect_block_number) {
if(!minode->indirect_block) {
minode->indirect_block =
sb_bread(vfs_inode->i_sb,
minode->inode.indirect_block_number);
if(!minode->indirect_block)
goto fail_get_block;
}
uint64_t *block_offset =
((uint64_t*)(minode->indirect_block->b_data) + (iblock-1));
mapped_block = le64_to_cpu(*block_offset);
if(!mapped_block) {
mapped_block = allocate_data_blocks(vfs_inode,1);
if (!mapped_block) {
SFSDBG(KERN_INFO "Error allocating indirect data block %s %d\n"
,__FUNCTION__,__LINE__);
goto fail_get_block;
}
}
*block_offset = cpu_to_le64(mapped_block);
mark_buffer_dirty(minode->indirect_block);
mapped_block = block_offset;
}
else { /*Allocate that indirect block and the block within*/
minode->inode.indirect_block_number = allocate_data_blocks(vfs_inode,1);
if(!minode->inode.indirect_block_number) {
SFSDBG(KERN_INFO "Error allocating indirect block %s %d\n"
,__FUNCTION__,__LINE__);
goto fail_get_block;
}
else
goto allocate_indirect_block;
}
}
else { /*This is the first block for the file*/
if( minode->inode.data_block_number ){
mapped_block = le64_to_cpu(minode->inode.data_block_number);
}
else
{
minode->inode.data_block_number = allocate_data_blocks(vfs_inode,1);
if(!minode->inode.data_block_number) {
SFSDBG(KERN_INFO "Error allocating direct block %s %d\n"
,__FUNCTION__,__LINE__);
goto fail_get_block;
}
mapped_block = minode->inode.data_block_number;
minode->inode.data_block_number = cpu_to_le64(
minode->inode.data_block_number);
}
}
}
else {
/*
* Find the mapping but don't create it.
*/
if(iblock) {
if(minode->inode.indirect_block_number) {
if(!minode->indirect_block) {
minode->indirect_block =
sb_bread(vfs_inode->i_sb,
minode->inode.indirect_block_number);
if(!minode->indirect_block)
goto fail_get_block;
}
uint64_t *block_offset =
((uint64_t*)(minode->indirect_block->b_data) + (iblock-1));
mapped_block = le64_to_cpu(*block_offset);
if(!mapped_block)
goto fail_get_block;
}
else
goto fail_get_block;
}
else {
if(!minode->inode.data_block_number)
goto fail_get_block;
mapped_block = le64_to_cpu(minode->inode.data_block_number);
}
}
set_buffer_new(bh_result);
map_bh(bh_result,vfs_inode->i_sb,mapped_block);
return 0;
fail_get_block:
return -EOF;
}
static int allocate_data_blocks(struct inode *vfs_inode,int nr_blocks)
{
struct simple_fs_sb_i *msblk = SIMPLEFS_SB(vfs_inode->i_sb);
struct simple_fs_inode_i *minode = SIMPLEFS_INODE(vfs_inode);
struct buffer_head *sb_buffer_bitmap = NULL;
char *bitmap_buffer = NULL;
int block_start = 0,block_no = 0;
int bitmap_index = 0;
int blocks_alloced = 0;
int buffer_offset = 0; /*How many b_this_page has been done on a single bh*/
int block_start_buffer_offset = 0;
int block_start_bitmap_index = 0;
if(!nr_blocks)
return 0;
mutex_lock(&msblk->sb_mutex);
new_bitmap_buffer:
sb_buffer_bitmap = msblk->block_bitmap[bitmap_index];
if(!sb_buffer_bitmap)
goto out_failed;
allocate_block:
bitmap_buffer = sb_buffer_bitmap->b_data;
if( nr_blocks &&
(block_no =
alloc_bmap(bitmap_buffer,sb_buffer_bitmap->b_size)) < 0) {
sb_buffer_bitmap = sb_buffer_bitmap->b_this_page;
if(sb_buffer_bitmap == mbslk->block_bitmap[bitmap_index]) {
bitmap_index++; /*Move to next buffer head in the array*/
buffer_offset = 0;
goto new_bitmap_buffer;
}
else
buffer_offset++;
goto allocate_block;
}
else if(block_no >= 0) {
nr_blocks--;
blocks_alloced++;
if(!block_start) {
block_start = block_no +
(((sb_buffer_bitmap->b_size * buffer_offset)
+ (PAGE_SIZE*bitmap_index)) << 3);
block_start_buffer_offset = buffer_offset;
block_start_bitmap_index = bitmap_index;
}
if(buffer_uptodate(sb_buffer_bitmap))
mark_buffer_dirty(sb_buffer_bitmap);
block_no = -1;
if(nr_blocks)
goto allocate_block;
}
simplefs_sync_metadata(sb);
mutex_unlock(&msblk->sb_mutex);
return block_start; /*Return starting block number of the allocated blocks*/
out_failed:
if(blocks_alloced) {
/*
* Get the starting buffer head from where allocations
* were started.
*/
sb_buffer_bitmap = msblk->block_bitmap[block_start_bitmap_index];
/*
* Get the starting block number relative to the buffer head.
*/
block_no = block_start - ((
(sb_buffer_bitmap->b_size * block_start_buffer_offset)
+(PAGE_SIZE * block_start_bitmap_index))) * 8;
/*
* Move to the correct buffer head within the page.
*/
while(block_start_buffer_offset) {
sb_buffer_bitmap = sb_buffer_bitmap->b_this_page;
block_start_buffer_offset--;
}
bitmap_buffer = sb_buffer_bitmap->b_data;
while(blocks_alloced) {
if(free_bmap(bitmap_buffer,sb_buffer_bitmap->b_size,block_no++)){
blocks_alloced--;
if(buffer_uptodate(sb_buffer_bitmap))
mark_buffer_dirty(sb_buffer_bitmap);
}
/*
* There was no freeing of block because this block_no didn't
* belonged the starting buffer head. We need to move the
* buffer head to new buffer or perhaps we might need to
* get a new msblk->block_bitmap[j].
*/
else {
sb_buffer_bitmap = sb_buffer_bitmap->b_this_page;
if( sb_buffer_bitmap == msblk->block_bitmap[block_start_bitmap_index] )
sb_buffer_bitmap = msblk->block_bitmap[++block_start_bitmap_index];
block_no = 0; /*This is relative to the buffer head*/
bitmap_buffer = sb_buffer_bitmap->b_data;
}
}
}
simplefs_sync_metadata(sb);
mutex_unlock(msblk->sb_mutex);
return 0;
}