microsoft
/
WSL2-Linux-Kernel
зеркало из https://github.com/microsoft/WSL2-Linux-Kernel.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность
WSL2-Linux-Kernel/fs/btrfs/super.c

3038 строки
78 KiB
C
Исходник Ответственный История

#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "ioctl.h"
#include "print-tree.h"
struct btrfs_iget_args {
u64 ino;
struct btrfs_root *root;
};
#define BTRFS_SUPER_MAGIC 0x9123682E
static struct inode_operations btrfs_dir_inode_operations;
static struct inode_operations btrfs_symlink_inode_operations;
static struct inode_operations btrfs_dir_ro_inode_operations;
static struct super_operations btrfs_super_ops;
static struct file_operations btrfs_dir_file_operations;
static struct inode_operations btrfs_file_inode_operations;
static struct address_space_operations btrfs_aops;
static struct address_space_operations btrfs_symlink_aops;
static struct file_operations btrfs_file_operations;
static int drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode,
u64 start, u64 end, u64 *hint_block);
static int btrfs_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create);
#define S_SHIFT 12
static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
[S_IFREG >> S_SHIFT] = BTRFS_FT_REG_FILE,
[S_IFDIR >> S_SHIFT] = BTRFS_FT_DIR,
[S_IFCHR >> S_SHIFT] = BTRFS_FT_CHRDEV,
[S_IFBLK >> S_SHIFT] = BTRFS_FT_BLKDEV,
[S_IFIFO >> S_SHIFT] = BTRFS_FT_FIFO,
[S_IFSOCK >> S_SHIFT] = BTRFS_FT_SOCK,
[S_IFLNK >> S_SHIFT] = BTRFS_FT_SYMLINK,
};
static void btrfs_read_locked_inode(struct inode *inode)
{
struct btrfs_path *path;
struct btrfs_inode_item *inode_item;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_key location;
u64 alloc_group_block;
int ret;
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
mutex_lock(&root->fs_info->fs_mutex);
memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
if (ret) {
btrfs_free_path(path);
goto make_bad;
}
inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
path->slots[0],
struct btrfs_inode_item);
inode->i_mode = btrfs_inode_mode(inode_item);
inode->i_nlink = btrfs_inode_nlink(inode_item);
inode->i_uid = btrfs_inode_uid(inode_item);
inode->i_gid = btrfs_inode_gid(inode_item);
inode->i_size = btrfs_inode_size(inode_item);
inode->i_atime.tv_sec = btrfs_timespec_sec(&inode_item->atime);
inode->i_atime.tv_nsec = btrfs_timespec_nsec(&inode_item->atime);
inode->i_mtime.tv_sec = btrfs_timespec_sec(&inode_item->mtime);
inode->i_mtime.tv_nsec = btrfs_timespec_nsec(&inode_item->mtime);
inode->i_ctime.tv_sec = btrfs_timespec_sec(&inode_item->ctime);
inode->i_ctime.tv_nsec = btrfs_timespec_nsec(&inode_item->ctime);
inode->i_blocks = btrfs_inode_nblocks(inode_item);
inode->i_generation = btrfs_inode_generation(inode_item);
alloc_group_block = btrfs_inode_block_group(inode_item);
BTRFS_I(inode)->block_group = btrfs_lookup_block_group(root->fs_info,
alloc_group_block);
btrfs_free_path(path);
inode_item = NULL;
mutex_unlock(&root->fs_info->fs_mutex);
switch (inode->i_mode & S_IFMT) {
#if 0
default:
init_special_inode(inode, inode->i_mode,
btrfs_inode_rdev(inode_item));
break;
#endif
case S_IFREG:
inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
break;
case S_IFDIR:
inode->i_fop = &btrfs_dir_file_operations;
if (root == root->fs_info->tree_root)
inode->i_op = &btrfs_dir_ro_inode_operations;
else
inode->i_op = &btrfs_dir_inode_operations;
break;
case S_IFLNK:
inode->i_op = &btrfs_symlink_inode_operations;
inode->i_mapping->a_ops = &btrfs_symlink_aops;
break;
}
return;
make_bad:
btrfs_release_path(root, path);
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
make_bad_inode(inode);
}
static void fill_inode_item(struct btrfs_inode_item *item,
struct inode *inode)
{
btrfs_set_inode_uid(item, inode->i_uid);
btrfs_set_inode_gid(item, inode->i_gid);
btrfs_set_inode_size(item, inode->i_size);
btrfs_set_inode_mode(item, inode->i_mode);
btrfs_set_inode_nlink(item, inode->i_nlink);
btrfs_set_timespec_sec(&item->atime, inode->i_atime.tv_sec);
btrfs_set_timespec_nsec(&item->atime, inode->i_atime.tv_nsec);
btrfs_set_timespec_sec(&item->mtime, inode->i_mtime.tv_sec);
btrfs_set_timespec_nsec(&item->mtime, inode->i_mtime.tv_nsec);
btrfs_set_timespec_sec(&item->ctime, inode->i_ctime.tv_sec);
btrfs_set_timespec_nsec(&item->ctime, inode->i_ctime.tv_nsec);
btrfs_set_inode_nblocks(item, inode->i_blocks);
btrfs_set_inode_generation(item, inode->i_generation);
btrfs_set_inode_block_group(item,
BTRFS_I(inode)->block_group->key.objectid);
}
static int btrfs_update_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode)
{
struct btrfs_inode_item *inode_item;
struct btrfs_path *path;
int ret;
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
ret = btrfs_lookup_inode(trans, root, path,
&BTRFS_I(inode)->location, 1);
if (ret) {
if (ret > 0)
ret = -ENOENT;
goto failed;
}
inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
path->slots[0],
struct btrfs_inode_item);
fill_inode_item(inode_item, inode);
btrfs_mark_buffer_dirty(path->nodes[0]);
ret = 0;
failed:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
}
static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *dir,
struct dentry *dentry)
{
struct btrfs_path *path;
const char *name = dentry->d_name.name;
int name_len = dentry->d_name.len;
int ret = 0;
u64 objectid;
struct btrfs_dir_item *di;
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
name, name_len, -1);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto err;
}
if (!di) {
ret = -ENOENT;
goto err;
}
objectid = btrfs_disk_key_objectid(&di->location);
ret = btrfs_delete_one_dir_name(trans, root, path, di);
BUG_ON(ret);
btrfs_release_path(root, path);
di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
objectid, name, name_len, -1);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto err;
}
if (!di) {
ret = -ENOENT;
goto err;
}
ret = btrfs_delete_one_dir_name(trans, root, path, di);
BUG_ON(ret);
dentry->d_inode->i_ctime = dir->i_ctime;
err:
btrfs_free_path(path);
if (!ret) {
dir->i_size -= name_len * 2;
btrfs_update_inode(trans, root, dir);
drop_nlink(dentry->d_inode);
btrfs_update_inode(trans, root, dentry->d_inode);
dir->i_sb->s_dirt = 1;
}
return ret;
}
static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
{
struct btrfs_root *root;
struct btrfs_trans_handle *trans;
int ret;
root = BTRFS_I(dir)->root;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
ret = btrfs_unlink_trans(trans, root, dir, dentry);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(root);
return ret;
}
static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
int err;
int ret;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_trans_handle *trans;
struct btrfs_key found_key;
int found_type;
struct btrfs_leaf *leaf;
char *goodnames = "..";
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
key.objectid = inode->i_ino;
key.offset = (u64)-1;
key.flags = (u32)-1;
while(1) {
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0) {
err = ret;
goto out;
}
BUG_ON(ret == 0);
if (path->slots[0] == 0) {
err = -ENOENT;
goto out;
}
path->slots[0]--;
leaf = btrfs_buffer_leaf(path->nodes[0]);
btrfs_disk_key_to_cpu(&found_key,
&leaf->items[path->slots[0]].key);
found_type = btrfs_key_type(&found_key);
if (found_key.objectid != inode->i_ino) {
err = -ENOENT;
goto out;
}
if ((found_type != BTRFS_DIR_ITEM_KEY &&
found_type != BTRFS_DIR_INDEX_KEY) ||
(!btrfs_match_dir_item_name(root, path, goodnames, 2) &&
!btrfs_match_dir_item_name(root, path, goodnames, 1))) {
err = -ENOTEMPTY;
goto out;
}
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
if (found_type == BTRFS_DIR_ITEM_KEY && found_key.offset == 1)
break;
btrfs_release_path(root, path);
}
ret = 0;
btrfs_release_path(root, path);
/* now the directory is empty */
err = btrfs_unlink_trans(trans, root, dir, dentry);
if (!err) {
inode->i_size = 0;
}
out:
btrfs_release_path(root, path);
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
ret = btrfs_end_transaction(trans, root);
btrfs_btree_balance_dirty(root);
if (ret && !err)
err = ret;
return err;
}
static int btrfs_free_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode)
{
struct btrfs_path *path;
int ret;
clear_inode(inode);
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
ret = btrfs_lookup_inode(trans, root, path,
&BTRFS_I(inode)->location, -1);
BUG_ON(ret);
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
btrfs_free_path(path);
return ret;
}
static void reada_truncate(struct btrfs_root *root, struct btrfs_path *path,
u64 objectid)
{
struct btrfs_node *node;
int i;
int nritems;
u64 item_objectid;
u64 blocknr;
int slot;
int ret;
if (!path->nodes[1])
return;
node = btrfs_buffer_node(path->nodes[1]);
slot = path->slots[1];
if (slot == 0)
return;
nritems = btrfs_header_nritems(&node->header);
for (i = slot - 1; i >= 0; i--) {
item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
if (item_objectid != objectid)
break;
blocknr = btrfs_node_blockptr(node, i);
ret = readahead_tree_block(root, blocknr);
if (ret)
break;
}
}
static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode)
{
int ret;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_disk_key *found_key;
u32 found_type;
struct btrfs_leaf *leaf;
struct btrfs_file_extent_item *fi;
u64 extent_start = 0;
u64 extent_num_blocks = 0;
u64 item_end = 0;
int found_extent;
int del_item;
path = btrfs_alloc_path();
BUG_ON(!path);
/* FIXME, add redo link to tree so we don't leak on crash */
key.objectid = inode->i_ino;
key.offset = (u64)-1;
key.flags = (u32)-1;
while(1) {
btrfs_init_path(path);
fi = NULL;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0) {
goto error;
}
if (ret > 0) {
BUG_ON(path->slots[0] == 0);
path->slots[0]--;
}
reada_truncate(root, path, inode->i_ino);
leaf = btrfs_buffer_leaf(path->nodes[0]);
found_key = &leaf->items[path->slots[0]].key;
found_type = btrfs_disk_key_type(found_key);
if (btrfs_disk_key_objectid(found_key) != inode->i_ino)
break;
if (found_type != BTRFS_CSUM_ITEM_KEY &&
found_type != BTRFS_DIR_ITEM_KEY &&
found_type != BTRFS_DIR_INDEX_KEY &&
found_type != BTRFS_EXTENT_DATA_KEY)
break;
item_end = btrfs_disk_key_offset(found_key);
if (found_type == BTRFS_EXTENT_DATA_KEY) {
fi = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
path->slots[0],
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(fi) !=
BTRFS_FILE_EXTENT_INLINE) {
item_end += btrfs_file_extent_num_blocks(fi) <<
inode->i_blkbits;
}
}
if (found_type == BTRFS_CSUM_ITEM_KEY) {
ret = btrfs_csum_truncate(trans, root, path,
inode->i_size);
BUG_ON(ret);
}
if (item_end < inode->i_size) {
if (found_type) {
btrfs_set_key_type(&key, found_type - 1);
continue;
}
break;
}
if (btrfs_disk_key_offset(found_key) >= inode->i_size)
del_item = 1;
else
del_item = 0;
found_extent = 0;
if (found_type == BTRFS_EXTENT_DATA_KEY &&
btrfs_file_extent_type(fi) !=
BTRFS_FILE_EXTENT_INLINE) {
u64 num_dec;
if (!del_item) {
u64 orig_num_blocks =
btrfs_file_extent_num_blocks(fi);
extent_num_blocks = inode->i_size -
btrfs_disk_key_offset(found_key) +
root->blocksize - 1;
extent_num_blocks >>= inode->i_blkbits;
btrfs_set_file_extent_num_blocks(fi,
extent_num_blocks);
inode->i_blocks -= (orig_num_blocks -
extent_num_blocks) << 3;
mark_buffer_dirty(path->nodes[0]);
} else {
extent_start =
btrfs_file_extent_disk_blocknr(fi);
extent_num_blocks =
btrfs_file_extent_disk_num_blocks(fi);
/* FIXME blocksize != 4096 */
num_dec = btrfs_file_extent_num_blocks(fi) << 3;
if (extent_start != 0) {
found_extent = 1;
inode->i_blocks -= num_dec;
}
}
}
if (del_item) {
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
} else {
break;
}
btrfs_release_path(root, path);
if (found_extent) {
ret = btrfs_free_extent(trans, root, extent_start,
extent_num_blocks, 0);
BUG_ON(ret);
}
}
ret = 0;
error:
btrfs_release_path(root, path);
btrfs_free_path(path);
inode->i_sb->s_dirt = 1;
return ret;
}
static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
{
struct inode *inode = mapping->host;
unsigned blocksize = 1 << inode->i_blkbits;
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
struct page *page;
char *kaddr;
int ret = 0;
struct btrfs_root *root = BTRFS_I(inode)->root;
u64 alloc_hint;
struct btrfs_key ins;
struct btrfs_trans_handle *trans;
if ((offset & (blocksize - 1)) == 0)
goto out;
ret = -ENOMEM;
page = grab_cache_page(mapping, index);
if (!page)
goto out;
if (!PageUptodate(page)) {
ret = mpage_readpage(page, btrfs_get_block);
lock_page(page);
if (!PageUptodate(page)) {
ret = -EIO;
goto out;
}
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
ret = drop_extents(trans, root, inode, page->index << PAGE_CACHE_SHIFT,
(page->index + 1) << PAGE_CACHE_SHIFT, &alloc_hint);
BUG_ON(ret);
ret = btrfs_alloc_extent(trans, root, inode->i_ino, 1,
alloc_hint, (u64)-1, &ins, 1);
BUG_ON(ret);
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
page->index << PAGE_CACHE_SHIFT,
ins.objectid, 1, 1);
BUG_ON(ret);
SetPageChecked(page);
kaddr = kmap(page);
memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
flush_dcache_page(page);
btrfs_csum_file_block(trans, root, inode->i_ino,
page->index << PAGE_CACHE_SHIFT,
kaddr, PAGE_CACHE_SIZE);
kunmap(page);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
set_page_dirty(page);
unlock_page(page);
page_cache_release(page);
out:
return ret;
}
static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
int err;
err = inode_change_ok(inode, attr);
if (err)
return err;
if (S_ISREG(inode->i_mode) &&
attr->ia_valid & ATTR_SIZE && attr->ia_size > inode->i_size) {
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
u64 mask = root->blocksize - 1;
u64 pos = (inode->i_size + mask) & ~mask;
u64 hole_size;
if (attr->ia_size <= pos)
goto out;
btrfs_truncate_page(inode->i_mapping, inode->i_size);
hole_size = (attr->ia_size - pos + mask) & ~mask;
hole_size >>= inode->i_blkbits;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
err = btrfs_insert_file_extent(trans, root, inode->i_ino,
pos, 0, 0, hole_size);
BUG_ON(err);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
}
out:
err = inode_setattr(inode, attr);
return err;
}
static void btrfs_delete_inode(struct inode *inode)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
truncate_inode_pages(&inode->i_data, 0);
if (is_bad_inode(inode)) {
goto no_delete;
}
inode->i_size = 0;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
ret = btrfs_truncate_in_trans(trans, root, inode);
BUG_ON(ret);
btrfs_free_inode(trans, root, inode);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(root);
return;
no_delete:
clear_inode(inode);
}
static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
struct btrfs_key *location)
{
const char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
struct btrfs_dir_item *di;
struct btrfs_path *path;
struct btrfs_root *root = BTRFS_I(dir)->root;
int ret;
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
namelen, 0);
if (!di || IS_ERR(di)) {
location->objectid = 0;
ret = 0;
goto out;
}
btrfs_disk_key_to_cpu(location, &di->location);
out:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
}
static int fixup_tree_root_location(struct btrfs_root *root,
struct btrfs_key *location,
struct btrfs_root **sub_root)
{
struct btrfs_path *path;
struct btrfs_root_item *ri;
if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
return 0;
if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
return 0;
path = btrfs_alloc_path();
BUG_ON(!path);
mutex_lock(&root->fs_info->fs_mutex);
*sub_root = btrfs_read_fs_root(root->fs_info, location);
if (IS_ERR(*sub_root))
return PTR_ERR(*sub_root);
ri = &(*sub_root)->root_item;
location->objectid = btrfs_root_dirid(ri);
location->flags = 0;
btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
location->offset = 0;
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
return 0;
}
static int btrfs_init_locked_inode(struct inode *inode, void *p)
{
struct btrfs_iget_args *args = p;
inode->i_ino = args->ino;
BTRFS_I(inode)->root = args->root;
return 0;
}
static int btrfs_find_actor(struct inode *inode, void *opaque)
{
struct btrfs_iget_args *args = opaque;
return (args->ino == inode->i_ino &&
args->root == BTRFS_I(inode)->root);
}
static struct inode *btrfs_iget_locked(struct super_block *s, u64 objectid,
struct btrfs_root *root)
{
struct inode *inode;
struct btrfs_iget_args args;
args.ino = objectid;
args.root = root;
inode = iget5_locked(s, objectid, btrfs_find_actor,
btrfs_init_locked_inode,
(void *)&args);
return inode;
}
static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct inode * inode;
struct btrfs_inode *bi = BTRFS_I(dir);
struct btrfs_root *root = bi->root;
struct btrfs_root *sub_root = root;
struct btrfs_key location;
int ret;
if (dentry->d_name.len > BTRFS_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
mutex_lock(&root->fs_info->fs_mutex);
ret = btrfs_inode_by_name(dir, dentry, &location);
mutex_unlock(&root->fs_info->fs_mutex);
if (ret < 0)
return ERR_PTR(ret);
inode = NULL;
if (location.objectid) {
ret = fixup_tree_root_location(root, &location, &sub_root);
if (ret < 0)
return ERR_PTR(ret);
if (ret > 0)
return ERR_PTR(-ENOENT);
inode = btrfs_iget_locked(dir->i_sb, location.objectid,
sub_root);
if (!inode)
return ERR_PTR(-EACCES);
if (inode->i_state & I_NEW) {
if (sub_root != root) {
printk("adding new root for inode %lu root %p (found %p)\n", inode->i_ino, sub_root, BTRFS_I(inode)->root);
igrab(inode);
sub_root->inode = inode;
}
BTRFS_I(inode)->root = sub_root;
memcpy(&BTRFS_I(inode)->location, &location,
sizeof(location));
btrfs_read_locked_inode(inode);
unlock_new_inode(inode);
}
}
return d_splice_alias(inode, dentry);
}
static void reada_leaves(struct btrfs_root *root, struct btrfs_path *path,
u64 objectid)
{
struct btrfs_node *node;
int i;
u32 nritems;
u64 item_objectid;
u64 blocknr;
int slot;
int ret;
if (!path->nodes[1])
return;
node = btrfs_buffer_node(path->nodes[1]);
slot = path->slots[1];
nritems = btrfs_header_nritems(&node->header);
for (i = slot + 1; i < nritems; i++) {
item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
if (item_objectid != objectid)
break;
blocknr = btrfs_node_blockptr(node, i);
ret = readahead_tree_block(root, blocknr);
if (ret)
break;
}
}
static unsigned char btrfs_filetype_table[] = {
DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
};
static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct inode *inode = filp->f_path.dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_item *item;
struct btrfs_dir_item *di;
struct btrfs_key key;
struct btrfs_path *path;
int ret;
u32 nritems;
struct btrfs_leaf *leaf;
int slot;
int advance;
unsigned char d_type;
int over = 0;
u32 di_cur;
u32 di_total;
u32 di_len;
int key_type = BTRFS_DIR_INDEX_KEY;
/* FIXME, use a real flag for deciding about the key type */
if (root->fs_info->tree_root == root)
key_type = BTRFS_DIR_ITEM_KEY;
mutex_lock(&root->fs_info->fs_mutex);
key.objectid = inode->i_ino;
key.flags = 0;
btrfs_set_key_type(&key, key_type);
key.offset = filp->f_pos;
path = btrfs_alloc_path();
btrfs_init_path(path);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto err;
advance = 0;
reada_leaves(root, path, inode->i_ino);
while(1) {
leaf = btrfs_buffer_leaf(path->nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
slot = path->slots[0];
if (advance || slot >= nritems) {
if (slot >= nritems -1) {
reada_leaves(root, path, inode->i_ino);
ret = btrfs_next_leaf(root, path);
if (ret)
break;
leaf = btrfs_buffer_leaf(path->nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
slot = path->slots[0];
} else {
slot++;
path->slots[0]++;
}
}
advance = 1;
item = leaf->items + slot;
if (btrfs_disk_key_objectid(&item->key) != key.objectid)
break;
if (btrfs_disk_key_type(&item->key) != key_type)
break;
if (btrfs_disk_key_offset(&item->key) < filp->f_pos)
continue;
filp->f_pos = btrfs_disk_key_offset(&item->key);
advance = 1;
di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
di_cur = 0;
di_total = btrfs_item_size(leaf->items + slot);
while(di_cur < di_total) {
d_type = btrfs_filetype_table[btrfs_dir_type(di)];
over = filldir(dirent, (const char *)(di + 1),
btrfs_dir_name_len(di),
btrfs_disk_key_offset(&item->key),
btrfs_disk_key_objectid(&di->location),
d_type);
if (over)
goto nopos;
di_len = btrfs_dir_name_len(di) + sizeof(*di);
di_cur += di_len;
di = (struct btrfs_dir_item *)((char *)di + di_len);
}
}
filp->f_pos++;
nopos:
ret = 0;
err:
btrfs_release_path(root, path);
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
return ret;
}
static void btrfs_put_super (struct super_block * sb)
{
struct btrfs_root *root = btrfs_sb(sb);
int ret;
ret = close_ctree(root);
if (ret) {
printk("close ctree returns %d\n", ret);
}
sb->s_fs_info = NULL;
}
static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
{
struct inode * inode;
struct dentry * root_dentry;
struct btrfs_super_block *disk_super;
struct btrfs_root *tree_root;
struct btrfs_inode *bi;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_magic = BTRFS_SUPER_MAGIC;
sb->s_op = &btrfs_super_ops;
sb->s_time_gran = 1;
tree_root = open_ctree(sb);
if (!tree_root) {
printk("btrfs: open_ctree failed\n");
return -EIO;
}
sb->s_fs_info = tree_root;
disk_super = tree_root->fs_info->disk_super;
printk("read in super total blocks %Lu root %Lu\n",
btrfs_super_total_blocks(disk_super),
btrfs_super_root_dir(disk_super));
inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super),
tree_root);
bi = BTRFS_I(inode);
bi->location.objectid = inode->i_ino;
bi->location.offset = 0;
bi->location.flags = 0;
bi->root = tree_root;
btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
if (!inode)
return -ENOMEM;
if (inode->i_state & I_NEW) {
btrfs_read_locked_inode(inode);
unlock_new_inode(inode);
}
root_dentry = d_alloc_root(inode);
if (!root_dentry) {
iput(inode);
return -ENOMEM;
}
sb->s_root = root_dentry;
btrfs_transaction_queue_work(tree_root, HZ * 30);
return 0;
}
static int btrfs_write_inode(struct inode *inode, int wait)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
int ret = 0;
if (wait) {
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
ret = btrfs_commit_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
}
return ret;
}
static void btrfs_dirty_inode(struct inode *inode)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
btrfs_update_inode(trans, root, inode);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(root);
}
static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid,
struct btrfs_block_group_cache *group,
int mode)
{
struct inode *inode;
struct btrfs_inode_item inode_item;
struct btrfs_key *location;
int ret;
int owner;
inode = new_inode(root->fs_info->sb);
if (!inode)
return ERR_PTR(-ENOMEM);
BTRFS_I(inode)->root = root;
if (mode & S_IFDIR)
owner = 0;
else
owner = 1;
group = btrfs_find_block_group(root, group, 0, 0, owner);
BTRFS_I(inode)->block_group = group;
inode->i_uid = current->fsuid;
inode->i_gid = current->fsgid;
inode->i_mode = mode;
inode->i_ino = objectid;
inode->i_blocks = 0;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
fill_inode_item(&inode_item, inode);
location = &BTRFS_I(inode)->location;
location->objectid = objectid;
location->flags = 0;
location->offset = 0;
btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
BUG_ON(ret);
insert_inode_hash(inode);
return inode;
}
static inline u8 btrfs_inode_type(struct inode *inode)
{
return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
}
static int btrfs_add_link(struct btrfs_trans_handle *trans,
struct dentry *dentry, struct inode *inode)
{
int ret;
struct btrfs_key key;
struct btrfs_root *root = BTRFS_I(dentry->d_parent->d_inode)->root;
key.objectid = inode->i_ino;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
key.offset = 0;
ret = btrfs_insert_dir_item(trans, root,
dentry->d_name.name, dentry->d_name.len,
dentry->d_parent->d_inode->i_ino,
&key, btrfs_inode_type(inode));
if (ret == 0) {
dentry->d_parent->d_inode->i_size += dentry->d_name.len * 2;
ret = btrfs_update_inode(trans, root,
dentry->d_parent->d_inode);
}
return ret;
}
static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
struct dentry *dentry, struct inode *inode)
{
int err = btrfs_add_link(trans, dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
return 0;
}
if (err > 0)
err = -EEXIST;
return err;
}
static int btrfs_create(struct inode *dir, struct dentry *dentry,
int mode, struct nameidata *nd)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct inode *inode;
int err;
int drop_inode = 0;
u64 objectid;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
if (err) {
err = -ENOSPC;
goto out_unlock;
}
inode = btrfs_new_inode(trans, root, objectid,
BTRFS_I(dir)->block_group, mode);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_unlock;
btrfs_set_trans_block_group(trans, inode);
err = btrfs_add_nondir(trans, dentry, inode);
if (err)
drop_inode = 1;
else {
inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
}
dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, inode);
btrfs_update_inode_block_group(trans, dir);
out_unlock:
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
if (drop_inode) {
inode_dec_link_count(inode);
iput(inode);
}
btrfs_btree_balance_dirty(root);
return err;
}
static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *dentry)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct inode *inode = old_dentry->d_inode;
int err;
int drop_inode = 0;
if (inode->i_nlink == 0)
return -ENOENT;
inc_nlink(inode);
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
atomic_inc(&inode->i_count);
err = btrfs_add_nondir(trans, dentry, inode);
if (err)
drop_inode = 1;
dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, dir);
btrfs_update_inode(trans, root, inode);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
if (drop_inode) {
inode_dec_link_count(inode);
iput(inode);
}
btrfs_btree_balance_dirty(root);
return err;
}
static int btrfs_make_empty_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 dirid)
{
int ret;
char buf[2];
struct btrfs_key key;
buf[0] = '.';
buf[1] = '.';
key.objectid = objectid;
key.offset = 0;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
ret = btrfs_insert_dir_item(trans, root, buf, 1, objectid,
&key, BTRFS_FT_DIR);
if (ret)
goto error;
key.objectid = dirid;
ret = btrfs_insert_dir_item(trans, root, buf, 2, objectid,
&key, BTRFS_FT_DIR);
if (ret)
goto error;
error:
return ret;
}
static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
struct inode *inode;
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(dir)->root;
int err = 0;
int drop_on_err = 0;
u64 objectid;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
if (IS_ERR(trans)) {
err = PTR_ERR(trans);
goto out_unlock;
}
err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
if (err) {
err = -ENOSPC;
goto out_unlock;
}
inode = btrfs_new_inode(trans, root, objectid,
BTRFS_I(dir)->block_group, S_IFDIR | mode);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto out_fail;
}
drop_on_err = 1;
inode->i_op = &btrfs_dir_inode_operations;
inode->i_fop = &btrfs_dir_file_operations;
btrfs_set_trans_block_group(trans, inode);
err = btrfs_make_empty_dir(trans, root, inode->i_ino, dir->i_ino);
if (err)
goto out_fail;
inode->i_size = 6;
err = btrfs_update_inode(trans, root, inode);
if (err)
goto out_fail;
err = btrfs_add_link(trans, dentry, inode);
if (err)
goto out_fail;
d_instantiate(dentry, inode);
drop_on_err = 0;
dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, inode);
btrfs_update_inode_block_group(trans, dir);
out_fail:
btrfs_end_transaction(trans, root);
out_unlock:
mutex_unlock(&root->fs_info->fs_mutex);
if (drop_on_err)
iput(inode);
btrfs_btree_balance_dirty(root);
return err;
}
static int btrfs_sync_file(struct file *file,
struct dentry *dentry, int datasync)
{
struct inode *inode = dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
struct btrfs_trans_handle *trans;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
ret = -ENOMEM;
goto out;
}
ret = btrfs_commit_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
out:
return ret > 0 ? EIO : ret;
}
static int btrfs_sync_fs(struct super_block *sb, int wait)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root;
int ret;
root = btrfs_sb(sb);
sb->s_dirt = 0;
if (!wait) {
filemap_flush(root->fs_info->btree_inode->i_mapping);
return 0;
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
ret = btrfs_commit_transaction(trans, root);
sb->s_dirt = 0;
BUG_ON(ret);
printk("btrfs sync_fs\n");
mutex_unlock(&root->fs_info->fs_mutex);
return 0;
}
#define BTRFS_GET_BLOCK_NO_CREATE 0
#define BTRFS_GET_BLOCK_CREATE 1
#define BTRFS_GET_BLOCK_NO_DIRECT 2
static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create)
{
int ret;
int err = 0;
u64 blocknr;
u64 extent_start = 0;
u64 extent_end = 0;
u64 objectid = inode->i_ino;
u32 found_type;
u64 alloc_hint = 0;
struct btrfs_path *path;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_file_extent_item *item;
struct btrfs_leaf *leaf;
struct btrfs_disk_key *found_key;
struct btrfs_trans_handle *trans = NULL;
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
if (create & BTRFS_GET_BLOCK_CREATE) {
WARN_ON(1);
/* this almost but not quite works */
trans = btrfs_start_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
goto out;
}
ret = drop_extents(trans, root, inode,
iblock << inode->i_blkbits,
(iblock + 1) << inode->i_blkbits,
&alloc_hint);
BUG_ON(ret);
}
ret = btrfs_lookup_file_extent(NULL, root, path,
inode->i_ino,
iblock << inode->i_blkbits, 0);
if (ret < 0) {
err = ret;
goto out;
}
if (ret != 0) {
if (path->slots[0] == 0) {
btrfs_release_path(root, path);
goto not_found;
}
path->slots[0]--;
}
item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_file_extent_item);
leaf = btrfs_buffer_leaf(path->nodes[0]);
blocknr = btrfs_file_extent_disk_blocknr(item);
blocknr += btrfs_file_extent_offset(item);
/* are we inside the extent that was found? */
found_key = &leaf->items[path->slots[0]].key;
found_type = btrfs_disk_key_type(found_key);
if (btrfs_disk_key_objectid(found_key) != objectid ||
found_type != BTRFS_EXTENT_DATA_KEY) {
extent_end = 0;
extent_start = 0;
goto not_found;
}
found_type = btrfs_file_extent_type(item);
extent_start = btrfs_disk_key_offset(&leaf->items[path->slots[0]].key);
if (found_type == BTRFS_FILE_EXTENT_REG) {
extent_start = extent_start >> inode->i_blkbits;
extent_end = extent_start + btrfs_file_extent_num_blocks(item);
err = 0;
if (btrfs_file_extent_disk_blocknr(item) == 0)
goto out;
if (iblock >= extent_start && iblock < extent_end) {
btrfs_map_bh_to_logical(root, result, blocknr +
iblock - extent_start);
goto out;
}
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
char *ptr;
char *map;
u32 size;
if (create & BTRFS_GET_BLOCK_NO_DIRECT) {
err = -EINVAL;
goto out;
}
size = btrfs_file_extent_inline_len(leaf->items +
path->slots[0]);
extent_end = (extent_start + size) >> inode->i_blkbits;
extent_start >>= inode->i_blkbits;
if (iblock < extent_start || iblock > extent_end) {
goto not_found;
}
ptr = btrfs_file_extent_inline_start(item);
map = kmap(result->b_page);
memcpy(map, ptr, size);
memset(map + size, 0, PAGE_CACHE_SIZE - size);
flush_dcache_page(result->b_page);
kunmap(result->b_page);
set_buffer_uptodate(result);
SetPageChecked(result->b_page);
btrfs_map_bh_to_logical(root, result, 0);
}
not_found:
if (create & BTRFS_GET_BLOCK_CREATE) {
struct btrfs_key ins;
ret = btrfs_alloc_extent(trans, root, inode->i_ino,
1, alloc_hint, (u64)-1,
&ins, 1);
BUG_ON(ret);
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
iblock << inode->i_blkbits,
ins.objectid, ins.offset,
ins.offset);
BUG_ON(ret);
SetPageChecked(result->b_page);
btrfs_map_bh_to_logical(root, result, ins.objectid);
}
out:
if (trans)
err = btrfs_end_transaction(trans, root);
btrfs_free_path(path);
return err;
}
static int btrfs_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create)
{
int err;
struct btrfs_root *root = BTRFS_I(inode)->root;
mutex_lock(&root->fs_info->fs_mutex);
err = btrfs_get_block_lock(inode, iblock, result, create);
mutex_unlock(&root->fs_info->fs_mutex);
return err;
}
static int btrfs_get_block_bmap(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
mutex_lock(&root->fs_info->fs_mutex);
btrfs_get_block_lock(inode, iblock, result, BTRFS_GET_BLOCK_NO_DIRECT);
mutex_unlock(&root->fs_info->fs_mutex);
return 0;
}
static sector_t btrfs_bmap(struct address_space *as, sector_t block)
{
return generic_block_bmap(as, block, btrfs_get_block_bmap);
}
static int btrfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
return block_prepare_write(page, from, to, btrfs_get_block);
}
static void btrfs_write_super(struct super_block *sb)
{
sb->s_dirt = 0;
}
static int btrfs_readpage(struct file *file, struct page *page)
{
return mpage_readpage(page, btrfs_get_block);
}
/*
* While block_write_full_page is writing back the dirty buffers under
* the page lock, whoever dirtied the buffers may decide to clean them
* again at any time. We handle that by only looking at the buffer
* state inside lock_buffer().
*
* If block_write_full_page() is called for regular writeback
* (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a
* locked buffer. This only can happen if someone has written the buffer
* directly, with submit_bh(). At the address_space level PageWriteback
* prevents this contention from occurring.
*/
static int __btrfs_write_full_page(struct inode *inode, struct page *page,
struct writeback_control *wbc)
{
int err;
sector_t block;
sector_t last_block;
struct buffer_head *bh, *head;
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
BUG_ON(!PageLocked(page));
last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
if (!page_has_buffers(page)) {
create_empty_buffers(page, blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
}
/*
* Be very careful. We have no exclusion from __set_page_dirty_buffers
* here, and the (potentially unmapped) buffers may become dirty at
* any time. If a buffer becomes dirty here after we've inspected it
* then we just miss that fact, and the page stays dirty.
*
* Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
* handle that here by just cleaning them.
*/
block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
head = page_buffers(page);
bh = head;
/*
* Get all the dirty buffers mapped to disk addresses and
* handle any aliases from the underlying blockdev's mapping.
*/
do {
if (block > last_block) {
/*
* mapped buffers outside i_size will occur, because
* this page can be outside i_size when there is a
* truncate in progress.
*/
/*
* The buffer was zeroed by block_write_full_page()
*/
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
} else if (!buffer_mapped(bh) && buffer_dirty(bh)) {
WARN_ON(bh->b_size != blocksize);
err = btrfs_get_block(inode, block, bh, 0);
if (err) {
printk("writepage going to recovery err %d\n", err);
goto recover;
}
if (buffer_new(bh)) {
/* blockdev mappings never come here */
clear_buffer_new(bh);
}
}
bh = bh->b_this_page;
block++;
} while (bh != head);
do {
if (!buffer_mapped(bh))
continue;
/*
* If it's a fully non-blocking write attempt and we cannot
* lock the buffer then redirty the page. Note that this can
* potentially cause a busy-wait loop from pdflush and kswapd
* activity, but those code paths have their own higher-level
* throttling.
*/
if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
lock_buffer(bh);
} else if (test_set_buffer_locked(bh)) {
redirty_page_for_writepage(wbc, page);
continue;
}
if (test_clear_buffer_dirty(bh) && bh->b_blocknr != 0) {
mark_buffer_async_write(bh);
} else {
unlock_buffer(bh);
}
} while ((bh = bh->b_this_page) != head);
/*
* The page and its buffers are protected by PageWriteback(), so we can
* drop the bh refcounts early.
*/
BUG_ON(PageWriteback(page));
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
submit_bh(WRITE, bh);
nr_underway++;
}
bh = next;
} while (bh != head);
unlock_page(page);
err = 0;
done:
if (nr_underway == 0) {
/*
* The page was marked dirty, but the buffers were
* clean. Someone wrote them back by hand with
* ll_rw_block/submit_bh. A rare case.
*/
int uptodate = 1;
do {
if (!buffer_uptodate(bh)) {
uptodate = 0;
break;
}
bh = bh->b_this_page;
} while (bh != head);
if (uptodate)
SetPageUptodate(page);
end_page_writeback(page);
}
return err;
recover:
/*
* ENOSPC, or some other error. We may already have added some
* blocks to the file, so we need to write these out to avoid
* exposing stale data.
* The page is currently locked and not marked for writeback
*/
bh = head;
/* Recovery: lock and submit the mapped buffers */
do {
if (buffer_mapped(bh) && buffer_dirty(bh)) {
lock_buffer(bh);
mark_buffer_async_write(bh);
} else {
/*
* The buffer may have been set dirty during
* attachment to a dirty page.
*/
clear_buffer_dirty(bh);
}
} while ((bh = bh->b_this_page) != head);
SetPageError(page);
BUG_ON(PageWriteback(page));
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
clear_buffer_dirty(bh);
submit_bh(WRITE, bh);
nr_underway++;
}
bh = next;
} while (bh != head);
unlock_page(page);
goto done;
}
/*
* The generic ->writepage function for buffer-backed address_spaces
*/
static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
{
struct inode * const inode = page->mapping->host;
loff_t i_size = i_size_read(inode);
const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
unsigned offset;
void *kaddr;
/* Is the page fully inside i_size? */
if (page->index < end_index)
return __btrfs_write_full_page(inode, page, wbc);
/* Is the page fully outside i_size? (truncate in progress) */
offset = i_size & (PAGE_CACHE_SIZE-1);
if (page->index >= end_index+1 || !offset) {
/*
* The page may have dirty, unmapped buffers. For example,
* they may have been added in ext3_writepage(). Make them
* freeable here, so the page does not leak.
*/
block_invalidatepage(page, 0);
unlock_page(page);
return 0; /* don't care */
}
/*
* The page straddles i_size. It must be zeroed out on each and every
* writepage invokation because it may be mmapped. "A file is mapped
* in multiples of the page size. For a file that is not a multiple of
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
kaddr = kmap_atomic(page, KM_USER0);
memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
return __btrfs_write_full_page(inode, page, wbc);
}
static void btrfs_truncate(struct inode *inode)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
struct btrfs_trans_handle *trans;
if (!S_ISREG(inode->i_mode))
return;
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return;
btrfs_truncate_page(inode->i_mapping, inode->i_size);
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
/* FIXME, add redo link to tree so we don't leak on crash */
ret = btrfs_truncate_in_trans(trans, root, inode);
BUG_ON(ret);
btrfs_update_inode(trans, root, inode);
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(root);
}
static int btrfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct inode *inode = page->mapping->host;
struct buffer_head *bh;
loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
SetPageUptodate(page);
bh = page_buffers(page);
set_buffer_uptodate(bh);
if (buffer_mapped(bh) && bh->b_blocknr != 0) {
set_page_dirty(page);
}
if (pos > inode->i_size) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
}
return 0;
}
static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
struct page **prepared_pages,
const char __user * buf)
{
long page_fault = 0;
int i;
int offset = pos & (PAGE_CACHE_SIZE - 1);
for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
size_t count = min_t(size_t,
PAGE_CACHE_SIZE - offset, write_bytes);
struct page *page = prepared_pages[i];
fault_in_pages_readable(buf, count);
/* Copy data from userspace to the current page */
kmap(page);
page_fault = __copy_from_user(page_address(page) + offset,
buf, count);
/* Flush processor's dcache for this page */
flush_dcache_page(page);
kunmap(page);
buf += count;
write_bytes -= count;
if (page_fault)
break;
}
return page_fault ? -EFAULT : 0;
}
static void btrfs_drop_pages(struct page **pages, size_t num_pages)
{
size_t i;
for (i = 0; i < num_pages; i++) {
if (!pages[i])
break;
unlock_page(pages[i]);
mark_page_accessed(pages[i]);
page_cache_release(pages[i]);
}
}
static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct file *file,
struct page **pages,
size_t num_pages,
loff_t pos,
size_t write_bytes)
{
int i;
int offset;
int err = 0;
int ret;
int this_write;
struct inode *inode = file->f_path.dentry->d_inode;
struct buffer_head *bh;
struct btrfs_file_extent_item *ei;
for (i = 0; i < num_pages; i++) {
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
/* FIXME, one block at a time */
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
bh = page_buffers(pages[i]);
if (buffer_mapped(bh) && bh->b_blocknr == 0) {
struct btrfs_key key;
struct btrfs_path *path;
char *ptr;
u32 datasize;
path = btrfs_alloc_path();
BUG_ON(!path);
key.objectid = inode->i_ino;
key.offset = pages[i]->index << PAGE_CACHE_SHIFT;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
BUG_ON(write_bytes >= PAGE_CACHE_SIZE);
datasize = offset +
btrfs_file_extent_calc_inline_size(write_bytes);
ret = btrfs_insert_empty_item(trans, root, path, &key,
datasize);
BUG_ON(ret);
ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
path->slots[0], struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(ei, trans->transid);
btrfs_set_file_extent_type(ei,
BTRFS_FILE_EXTENT_INLINE);
ptr = btrfs_file_extent_inline_start(ei);
btrfs_memcpy(root, path->nodes[0]->b_data,
ptr, bh->b_data, offset + write_bytes);
mark_buffer_dirty(path->nodes[0]);
btrfs_free_path(path);
} else if (buffer_mapped(bh)) {
btrfs_csum_file_block(trans, root, inode->i_ino,
pages[i]->index << PAGE_CACHE_SHIFT,
kmap(pages[i]), PAGE_CACHE_SIZE);
kunmap(pages[i]);
}
SetPageChecked(pages[i]);
// btrfs_update_inode_block_group(trans, inode);
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
ret = btrfs_commit_write(file, pages[i], offset,
offset + this_write);
pos += this_write;
if (ret) {
err = ret;
goto failed;
}
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
}
failed:
return err;
}
static int drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode,
u64 start, u64 end, u64 *hint_block)
{
int ret;
struct btrfs_key key;
struct btrfs_leaf *leaf;
int slot;
struct btrfs_file_extent_item *extent;
u64 extent_end = 0;
int keep;
struct btrfs_file_extent_item old;
struct btrfs_path *path;
u64 search_start = start;
int bookend;
int found_type;
int found_extent;
int found_inline;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while(1) {
btrfs_release_path(root, path);
ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
search_start, -1);
if (ret < 0)
goto out;
if (ret > 0) {
if (path->slots[0] == 0) {
ret = 0;
goto out;
}
path->slots[0]--;
}
keep = 0;
bookend = 0;
found_extent = 0;
found_inline = 0;
extent = NULL;
leaf = btrfs_buffer_leaf(path->nodes[0]);
slot = path->slots[0];
btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
if (key.offset >= end || key.objectid != inode->i_ino) {
ret = 0;
goto out;
}
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY) {
ret = 0;
goto out;
}
extent = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(extent);
if (found_type == BTRFS_FILE_EXTENT_REG) {
extent_end = key.offset +
(btrfs_file_extent_num_blocks(extent) <<
inode->i_blkbits);
found_extent = 1;
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
found_inline = 1;
extent_end = key.offset +
btrfs_file_extent_inline_len(leaf->items + slot);
}
if (!found_extent && !found_inline) {
ret = 0;
goto out;
}
if (search_start >= extent_end) {
ret = 0;
goto out;
}
if (found_inline) {
u64 mask = root->blocksize - 1;
search_start = (extent_end + mask) & ~mask;
} else
search_start = extent_end;
if (end < extent_end && end >= key.offset) {
if (found_extent) {
u64 disk_blocknr =
btrfs_file_extent_disk_blocknr(extent);
u64 disk_num_blocks =
btrfs_file_extent_disk_num_blocks(extent);
memcpy(&old, extent, sizeof(old));
if (disk_blocknr != 0) {
ret = btrfs_inc_extent_ref(trans, root,
disk_blocknr, disk_num_blocks);
BUG_ON(ret);
}
}
WARN_ON(found_inline);
bookend = 1;
}
if (start > key.offset) {
u64 new_num;
u64 old_num;
/* truncate existing extent */
keep = 1;
WARN_ON(start & (root->blocksize - 1));
if (found_extent) {
new_num = (start - key.offset) >>
inode->i_blkbits;
old_num = btrfs_file_extent_num_blocks(extent);
*hint_block =
btrfs_file_extent_disk_blocknr(extent);
if (btrfs_file_extent_disk_blocknr(extent)) {
inode->i_blocks -=
(old_num - new_num) << 3;
}
btrfs_set_file_extent_num_blocks(extent,
new_num);
mark_buffer_dirty(path->nodes[0]);
} else {
WARN_ON(1);
}
}
if (!keep) {
u64 disk_blocknr = 0;
u64 disk_num_blocks = 0;
u64 extent_num_blocks = 0;
if (found_extent) {
disk_blocknr =
btrfs_file_extent_disk_blocknr(extent);
disk_num_blocks =
btrfs_file_extent_disk_num_blocks(extent);
extent_num_blocks =
btrfs_file_extent_num_blocks(extent);
*hint_block =
btrfs_file_extent_disk_blocknr(extent);
}
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
btrfs_release_path(root, path);
extent = NULL;
if (found_extent && disk_blocknr != 0) {
inode->i_blocks -= extent_num_blocks << 3;
ret = btrfs_free_extent(trans, root,
disk_blocknr,
disk_num_blocks, 0);
}
BUG_ON(ret);
if (!bookend && search_start >= end) {
ret = 0;
goto out;
}
if (!bookend)
continue;
}
if (bookend && found_extent) {
/* create bookend */
struct btrfs_key ins;
ins.objectid = inode->i_ino;
ins.offset = end;
ins.flags = 0;
btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
btrfs_release_path(root, path);
ret = btrfs_insert_empty_item(trans, root, path, &ins,
sizeof(*extent));
BUG_ON(ret);
extent = btrfs_item_ptr(
btrfs_buffer_leaf(path->nodes[0]),
path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_disk_blocknr(extent,
btrfs_file_extent_disk_blocknr(&old));
btrfs_set_file_extent_disk_num_blocks(extent,
btrfs_file_extent_disk_num_blocks(&old));
btrfs_set_file_extent_offset(extent,
btrfs_file_extent_offset(&old) +
((end - key.offset) >> inode->i_blkbits));
WARN_ON(btrfs_file_extent_num_blocks(&old) <
(extent_end - end) >> inode->i_blkbits);
btrfs_set_file_extent_num_blocks(extent,
(extent_end - end) >> inode->i_blkbits);
btrfs_set_file_extent_type(extent,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(extent,
btrfs_file_extent_generation(&old));
btrfs_mark_buffer_dirty(path->nodes[0]);
if (btrfs_file_extent_disk_blocknr(&old) != 0) {
inode->i_blocks +=
btrfs_file_extent_num_blocks(extent) << 3;
}
ret = 0;
goto out;
}
}
out:
btrfs_free_path(path);
return ret;
}
static int prepare_pages(struct btrfs_root *root,
struct file *file,
struct page **pages,
size_t num_pages,
loff_t pos,
unsigned long first_index,
unsigned long last_index,
size_t write_bytes,
u64 alloc_extent_start)
{
int i;
unsigned long index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = file->f_path.dentry->d_inode;
int offset;
int err = 0;
int this_write;
struct buffer_head *bh;
struct buffer_head *head;
loff_t isize = i_size_read(inode);
memset(pages, 0, num_pages * sizeof(struct page *));
for (i = 0; i < num_pages; i++) {
pages[i] = grab_cache_page(inode->i_mapping, index + i);
if (!pages[i]) {
err = -ENOMEM;
goto failed_release;
}
cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
wait_on_page_writeback(pages[i]);
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
if (!page_has_buffers(pages[i])) {
create_empty_buffers(pages[i],
root->fs_info->sb->s_blocksize,
(1 << BH_Uptodate));
}
head = page_buffers(pages[i]);
bh = head;
do {
err = btrfs_map_bh_to_logical(root, bh,
alloc_extent_start);
BUG_ON(err);
if (err)
goto failed_truncate;
bh = bh->b_this_page;
if (alloc_extent_start)
alloc_extent_start++;
} while (bh != head);
pos += this_write;
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
}
return 0;
failed_release:
btrfs_drop_pages(pages, num_pages);
return err;
failed_truncate:
btrfs_drop_pages(pages, num_pages);
if (pos > isize)
vmtruncate(inode, isize);
return err;
}
static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
loff_t pos;
size_t num_written = 0;
int err = 0;
int ret = 0;
struct inode *inode = file->f_path.dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct page *pages[8];
struct page *pinned[2];
unsigned long first_index;
unsigned long last_index;
u64 start_pos;
u64 num_blocks;
u64 alloc_extent_start;
u64 hint_block;
struct btrfs_trans_handle *trans;
struct btrfs_key ins;
pinned[0] = NULL;
pinned[1] = NULL;
if (file->f_flags & O_DIRECT)
return -EINVAL;
pos = *ppos;
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
current->backing_dev_info = inode->i_mapping->backing_dev_info;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
goto out;
if (count == 0)
goto out;
err = remove_suid(file->f_path.dentry);
if (err)
goto out;
file_update_time(file);
start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
num_blocks = (count + pos - start_pos + root->blocksize - 1) >>
inode->i_blkbits;
mutex_lock(&inode->i_mutex);
first_index = pos >> PAGE_CACHE_SHIFT;
last_index = (pos + count) >> PAGE_CACHE_SHIFT;
if ((pos & (PAGE_CACHE_SIZE - 1))) {
pinned[0] = grab_cache_page(inode->i_mapping, first_index);
if (!PageUptodate(pinned[0])) {
ret = mpage_readpage(pinned[0], btrfs_get_block);
BUG_ON(ret);
wait_on_page_locked(pinned[0]);
} else {
unlock_page(pinned[0]);
}
}
if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
pinned[1] = grab_cache_page(inode->i_mapping, last_index);
if (!PageUptodate(pinned[1])) {
ret = mpage_readpage(pinned[1], btrfs_get_block);
BUG_ON(ret);
wait_on_page_locked(pinned[1]);
} else {
unlock_page(pinned[1]);
}
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
mutex_unlock(&root->fs_info->fs_mutex);
goto out_unlock;
}
btrfs_set_trans_block_group(trans, inode);
/* FIXME blocksize != 4096 */
inode->i_blocks += num_blocks << 3;
hint_block = 0;
if (start_pos < inode->i_size) {
/* FIXME blocksize != pagesize */
ret = drop_extents(trans, root, inode,
start_pos,
(pos + count + root->blocksize -1) &
~((u64)root->blocksize - 1), &hint_block);
BUG_ON(ret);
}
if (inode->i_size < start_pos) {
u64 last_pos_in_file;
u64 hole_size;
u64 mask = root->blocksize - 1;
last_pos_in_file = (inode->i_size + mask) & ~mask;
hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
hole_size >>= inode->i_blkbits;
if (last_pos_in_file < start_pos) {
ret = btrfs_insert_file_extent(trans, root,
inode->i_ino,
last_pos_in_file,
0, 0, hole_size);
}
BUG_ON(ret);
}
if (inode->i_size >= PAGE_CACHE_SIZE || pos + count < inode->i_size ||
pos + count - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
ret = btrfs_alloc_extent(trans, root, inode->i_ino,
num_blocks, hint_block, (u64)-1,
&ins, 1);
BUG_ON(ret);
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
start_pos, ins.objectid, ins.offset,
ins.offset);
BUG_ON(ret);
} else {
ins.offset = 0;
ins.objectid = 0;
}
BUG_ON(ret);
alloc_extent_start = ins.objectid;
// btrfs_update_inode_block_group(trans, inode);
ret = btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
while(count > 0) {
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
size_t write_bytes = min(count, PAGE_CACHE_SIZE - offset);
size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
memset(pages, 0, sizeof(pages));
ret = prepare_pages(root, file, pages, num_pages,
pos, first_index, last_index,
write_bytes, alloc_extent_start);
BUG_ON(ret);
/* FIXME blocks != pagesize */
if (alloc_extent_start)
alloc_extent_start += num_pages;
ret = btrfs_copy_from_user(pos, num_pages,
write_bytes, pages, buf);
BUG_ON(ret);
ret = dirty_and_release_pages(NULL, root, file, pages,
num_pages, pos, write_bytes);
BUG_ON(ret);
btrfs_drop_pages(pages, num_pages);
buf += write_bytes;
count -= write_bytes;
pos += write_bytes;
num_written += write_bytes;
balance_dirty_pages_ratelimited(inode->i_mapping);
btrfs_btree_balance_dirty(root);
cond_resched();
}
out_unlock:
mutex_unlock(&inode->i_mutex);
out:
if (pinned[0])
page_cache_release(pinned[0]);
if (pinned[1])
page_cache_release(pinned[1]);
*ppos = pos;
current->backing_dev_info = NULL;
mark_inode_dirty(inode);
return num_written ? num_written : err;
}
static int btrfs_read_actor(read_descriptor_t *desc, struct page *page,
unsigned long offset, unsigned long size)
{
char *kaddr;
unsigned long left, count = desc->count;
struct inode *inode = page->mapping->host;
if (size > count)
size = count;
if (!PageChecked(page)) {
/* FIXME, do it per block */
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
struct buffer_head *bh;
if (page_has_buffers(page)) {
bh = page_buffers(page);
if (!buffer_mapped(bh)) {
SetPageChecked(page);
goto checked;
}
}
ret = btrfs_csum_verify_file_block(root,
page->mapping->host->i_ino,
page->index << PAGE_CACHE_SHIFT,
kmap(page), PAGE_CACHE_SIZE);
if (ret) {
if (ret != -ENOENT) {
printk("failed to verify ino %lu page %lu ret %d\n",
page->mapping->host->i_ino,
page->index, ret);
memset(page_address(page), 1, PAGE_CACHE_SIZE);
flush_dcache_page(page);
}
}
SetPageChecked(page);
kunmap(page);
}
checked:
/*
* Faults on the destination of a read are common, so do it before
* taking the kmap.
*/
if (!fault_in_pages_writeable(desc->arg.buf, size)) {
kaddr = kmap_atomic(page, KM_USER0);
left = __copy_to_user_inatomic(desc->arg.buf,
kaddr + offset, size);
kunmap_atomic(kaddr, KM_USER0);
if (left == 0)
goto success;
}
/* Do it the slow way */
kaddr = kmap(page);
left = __copy_to_user(desc->arg.buf, kaddr + offset, size);
kunmap(page);
if (left) {
size -= left;
desc->error = -EFAULT;
}
success:
desc->count = count - size;
desc->written += size;
desc->arg.buf += size;
return size;
}
/**
* btrfs_file_aio_read - filesystem read routine
* @iocb: kernel I/O control block
* @iov: io vector request
* @nr_segs: number of segments in the iovec
* @pos: current file position
*/
static ssize_t btrfs_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *filp = iocb->ki_filp;
ssize_t retval;
unsigned long seg;
size_t count;
loff_t *ppos = &iocb->ki_pos;
count = 0;
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *iv = &iov[seg];
/*
* If any segment has a negative length, or the cumulative
* length ever wraps negative then return -EINVAL.
*/
count += iv->iov_len;
if (unlikely((ssize_t)(count|iv->iov_len) < 0))
return -EINVAL;
if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
continue;
if (seg == 0)
return -EFAULT;
nr_segs = seg;
count -= iv->iov_len; /* This segment is no good */
break;
}
retval = 0;
if (count) {
for (seg = 0; seg < nr_segs; seg++) {
read_descriptor_t desc;
desc.written = 0;
desc.arg.buf = iov[seg].iov_base;
desc.count = iov[seg].iov_len;
if (desc.count == 0)
continue;
desc.error = 0;
do_generic_file_read(filp, ppos, &desc,
btrfs_read_actor);
retval += desc.written;
if (desc.error) {
retval = retval ?: desc.error;
break;
}
}
}
return retval;
}
static int create_subvol(struct btrfs_root *root, char *name, int namelen)
{
struct btrfs_trans_handle *trans;
struct btrfs_key key;
struct btrfs_root_item root_item;
struct btrfs_inode_item *inode_item;
struct buffer_head *subvol;
struct btrfs_leaf *leaf;
struct btrfs_root *new_root;
struct inode *inode;
struct inode *dir;
int ret;
u64 objectid;
u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
BUG_ON(!trans);
subvol = btrfs_alloc_free_block(trans, root, 0);
if (subvol == NULL)
return -ENOSPC;
leaf = btrfs_buffer_leaf(subvol);
btrfs_set_header_nritems(&leaf->header, 0);
btrfs_set_header_level(&leaf->header, 0);
btrfs_set_header_blocknr(&leaf->header, bh_blocknr(subvol));
btrfs_set_header_generation(&leaf->header, trans->transid);
btrfs_set_header_owner(&leaf->header, root->root_key.objectid);
memcpy(leaf->header.fsid, root->fs_info->disk_super->fsid,
sizeof(leaf->header.fsid));
mark_buffer_dirty(subvol);
inode_item = &root_item.inode;
memset(inode_item, 0, sizeof(*inode_item));
btrfs_set_inode_generation(inode_item, 1);
btrfs_set_inode_size(inode_item, 3);
btrfs_set_inode_nlink(inode_item, 1);
btrfs_set_inode_nblocks(inode_item, 1);
btrfs_set_inode_mode(inode_item, S_IFDIR | 0755);
btrfs_set_root_blocknr(&root_item, bh_blocknr(subvol));
btrfs_set_root_refs(&root_item, 1);
brelse(subvol);
subvol = NULL;
ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
0, &objectid);
BUG_ON(ret);
btrfs_set_root_dirid(&root_item, new_dirid);
key.objectid = objectid;
key.offset = 1;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
&root_item);
BUG_ON(ret);
/*
* insert the directory item
*/
key.offset = (u64)-1;
dir = root->fs_info->sb->s_root->d_inode;
ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
name, namelen, dir->i_ino, &key,
BTRFS_FT_DIR);
BUG_ON(ret);
ret = btrfs_commit_transaction(trans, root);
BUG_ON(ret);
new_root = btrfs_read_fs_root(root->fs_info, &key);
BUG_ON(!new_root);
trans = btrfs_start_transaction(new_root, 1);
BUG_ON(!trans);
inode = btrfs_new_inode(trans, new_root, new_dirid,
BTRFS_I(dir)->block_group, S_IFDIR | 0700);
inode->i_op = &btrfs_dir_inode_operations;
inode->i_fop = &btrfs_dir_file_operations;
ret = btrfs_make_empty_dir(trans, new_root, new_dirid, new_dirid);
BUG_ON(ret);
inode->i_nlink = 1;
inode->i_size = 6;
ret = btrfs_update_inode(trans, new_root, inode);
BUG_ON(ret);
ret = btrfs_commit_transaction(trans, new_root);
BUG_ON(ret);
iput(inode);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(root);
return 0;
}
static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
{
struct btrfs_trans_handle *trans;
struct btrfs_key key;
struct btrfs_root_item new_root_item;
int ret;
u64 objectid;
if (!root->ref_cows)
return -EINVAL;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
BUG_ON(!trans);
ret = btrfs_update_inode(trans, root, root->inode);
BUG_ON(ret);
ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
0, &objectid);
BUG_ON(ret);
memcpy(&new_root_item, &root->root_item,
sizeof(new_root_item));
key.objectid = objectid;
key.offset = 1;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
btrfs_set_root_blocknr(&new_root_item, bh_blocknr(root->node));
ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
&new_root_item);
BUG_ON(ret);
/*
* insert the directory item
*/
key.offset = (u64)-1;
ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
name, namelen,
root->fs_info->sb->s_root->d_inode->i_ino,
&key, BTRFS_FT_DIR);
BUG_ON(ret);
ret = btrfs_inc_root_ref(trans, root);
BUG_ON(ret);
ret = btrfs_commit_transaction(trans, root);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(root);
return 0;
}
static int btrfs_ioctl(struct inode *inode, struct file *filp, unsigned int
cmd, unsigned long arg)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_ioctl_vol_args vol_args;
int ret = 0;
struct btrfs_dir_item *di;
int namelen;
struct btrfs_path *path;
u64 root_dirid;
switch (cmd) {
case BTRFS_IOC_SNAP_CREATE:
if (copy_from_user(&vol_args,
(struct btrfs_ioctl_vol_args __user *)arg,
sizeof(vol_args)))
return -EFAULT;
namelen = strlen(vol_args.name);
if (namelen > BTRFS_VOL_NAME_MAX)
return -EINVAL;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
mutex_lock(&root->fs_info->fs_mutex);
di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
path, root_dirid,
vol_args.name, namelen, 0);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_free_path(path);
if (di && !IS_ERR(di))
return -EEXIST;
if (root == root->fs_info->tree_root)
ret = create_subvol(root, vol_args.name, namelen);
else
ret = create_snapshot(root, vol_args.name, namelen);
WARN_ON(ret);
break;
default:
return -ENOTTY;
}
return ret;
}
#ifdef CONFIG_COMPAT
static long btrfs_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct inode *inode = file->f_path.dentry->d_inode;
int ret;
lock_kernel();
ret = btrfs_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
unlock_kernel();
return ret;
}
#endif
static struct kmem_cache *btrfs_inode_cachep;
struct kmem_cache *btrfs_trans_handle_cachep;
struct kmem_cache *btrfs_transaction_cachep;
struct kmem_cache *btrfs_bit_radix_cachep;
struct kmem_cache *btrfs_path_cachep;
/*
* Called inside transaction, so use GFP_NOFS
*/
static struct inode *btrfs_alloc_inode(struct super_block *sb)
{
struct btrfs_inode *ei;
ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
return &ei->vfs_inode;
}
static void btrfs_destroy_inode(struct inode *inode)
{
WARN_ON(!list_empty(&inode->i_dentry));
WARN_ON(inode->i_data.nrpages);
kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
}
static void init_once(void * foo, struct kmem_cache * cachep,
unsigned long flags)
{
struct btrfs_inode *ei = (struct btrfs_inode *) foo;
if ((flags & (SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
inode_init_once(&ei->vfs_inode);
}
}
static int init_inodecache(void)
{
btrfs_inode_cachep = kmem_cache_create("btrfs_inode_cache",
sizeof(struct btrfs_inode),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
init_once, NULL);
btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle_cache",
sizeof(struct btrfs_trans_handle),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
NULL, NULL);
btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction_cache",
sizeof(struct btrfs_transaction),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
NULL, NULL);
btrfs_path_cachep = kmem_cache_create("btrfs_path_cache",
sizeof(struct btrfs_transaction),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
NULL, NULL);
btrfs_bit_radix_cachep = kmem_cache_create("btrfs_radix",
256,
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD |
SLAB_DESTROY_BY_RCU),
NULL, NULL);
if (btrfs_inode_cachep == NULL || btrfs_trans_handle_cachep == NULL ||
btrfs_transaction_cachep == NULL || btrfs_bit_radix_cachep == NULL)
return -ENOMEM;
return 0;
}
static void destroy_inodecache(void)
{
kmem_cache_destroy(btrfs_inode_cachep);
kmem_cache_destroy(btrfs_trans_handle_cachep);
kmem_cache_destroy(btrfs_transaction_cachep);
kmem_cache_destroy(btrfs_bit_radix_cachep);
kmem_cache_destroy(btrfs_path_cachep);
}
static int btrfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_bdev(fs_type, flags, dev_name, data,
btrfs_fill_super, mnt);
}
static int btrfs_getattr(struct vfsmount *mnt,
struct dentry *dentry, struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
generic_fillattr(inode, stat);
stat->blksize = 256 * 1024;
return 0;
}
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct btrfs_root *root = btrfs_sb(dentry->d_sb);
struct btrfs_super_block *disk_super = root->fs_info->disk_super;
buf->f_namelen = BTRFS_NAME_LEN;
buf->f_blocks = btrfs_super_total_blocks(disk_super);
buf->f_bfree = buf->f_blocks - btrfs_super_blocks_used(disk_super);
buf->f_bavail = buf->f_bfree;
buf->f_bsize = dentry->d_sb->s_blocksize;
buf->f_type = BTRFS_SUPER_MAGIC;
return 0;
}
static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
struct inode * new_dir,struct dentry *new_dentry)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(old_dir)->root;
struct inode *new_inode = new_dentry->d_inode;
struct inode *old_inode = old_dentry->d_inode;
struct timespec ctime = CURRENT_TIME;
struct btrfs_path *path;
struct btrfs_dir_item *di;
int ret;
if (S_ISDIR(old_inode->i_mode) && new_inode &&
new_inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
return -ENOTEMPTY;
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, new_dir);
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out_fail;
}
old_dentry->d_inode->i_nlink++;
old_dir->i_ctime = old_dir->i_mtime = ctime;
new_dir->i_ctime = new_dir->i_mtime = ctime;
old_inode->i_ctime = ctime;
if (S_ISDIR(old_inode->i_mode) && old_dir != new_dir) {
struct btrfs_key *location = &BTRFS_I(new_dir)->location;
u64 old_parent_oid;
di = btrfs_lookup_dir_item(trans, root, path, old_inode->i_ino,
"..", 2, -1);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out_fail;
}
if (!di) {
ret = -ENOENT;
goto out_fail;
}
old_parent_oid = btrfs_disk_key_objectid(&di->location);
ret = btrfs_del_item(trans, root, path);
if (ret) {
ret = -EIO;
goto out_fail;
}
btrfs_release_path(root, path);
di = btrfs_lookup_dir_index_item(trans, root, path,
old_inode->i_ino,
old_parent_oid,
"..", 2, -1);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out_fail;
}
if (!di) {
ret = -ENOENT;
goto out_fail;
}
ret = btrfs_del_item(trans, root, path);
if (ret) {
ret = -EIO;
goto out_fail;
}
btrfs_release_path(root, path);
ret = btrfs_insert_dir_item(trans, root, "..", 2,
old_inode->i_ino, location,
BTRFS_FT_DIR);
if (ret)
goto out_fail;
}
ret = btrfs_unlink_trans(trans, root, old_dir, old_dentry);
if (ret)
goto out_fail;
if (new_inode) {
new_inode->i_ctime = CURRENT_TIME;
ret = btrfs_unlink_trans(trans, root, new_dir, new_dentry);
if (ret)
goto out_fail;
if (S_ISDIR(new_inode->i_mode))
clear_nlink(new_inode);
else
drop_nlink(new_inode);
btrfs_update_inode(trans, root, new_inode);
}
ret = btrfs_add_link(trans, new_dentry, old_inode);
if (ret)
goto out_fail;
out_fail:
btrfs_free_path(path);
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
return ret;
}
static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
const char *symname)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_path *path;
struct btrfs_key key;
struct inode *inode;
int err;
int drop_inode = 0;
u64 objectid;
int name_len;
int datasize;
char *ptr;
struct btrfs_file_extent_item *ei;
name_len = strlen(symname) + 1;
if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
return -ENAMETOOLONG;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
if (err) {
err = -ENOSPC;
goto out_unlock;
}
inode = btrfs_new_inode(trans, root, objectid,
BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_unlock;
btrfs_set_trans_block_group(trans, inode);
err = btrfs_add_nondir(trans, dentry, inode);
if (err)
drop_inode = 1;
else {
inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
}
dir->i_sb->s_dirt = 1;
btrfs_update_inode_block_group(trans, inode);
btrfs_update_inode_block_group(trans, dir);
if (drop_inode)
goto out_unlock;
path = btrfs_alloc_path();
BUG_ON(!path);
key.objectid = inode->i_ino;
key.offset = 0;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
datasize = btrfs_file_extent_calc_inline_size(name_len);
err = btrfs_insert_empty_item(trans, root, path, &key,
datasize);
BUG_ON(err);
ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
path->slots[0], struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(ei, trans->transid);
btrfs_set_file_extent_type(ei,
BTRFS_FILE_EXTENT_INLINE);
ptr = btrfs_file_extent_inline_start(ei);
btrfs_memcpy(root, path->nodes[0]->b_data,
ptr, symname, name_len);
mark_buffer_dirty(path->nodes[0]);
btrfs_free_path(path);
inode->i_op = &btrfs_symlink_inode_operations;
inode->i_mapping->a_ops = &btrfs_symlink_aops;
inode->i_size = name_len - 1;
btrfs_update_inode(trans, root, inode);
err = 0;
out_unlock:
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
if (drop_inode) {
inode_dec_link_count(inode);
iput(inode);
}
btrfs_btree_balance_dirty(root);
return err;
}
static struct file_system_type btrfs_fs_type = {
.owner = THIS_MODULE,
.name = "btrfs",
.get_sb = btrfs_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static struct super_operations btrfs_super_ops = {
.delete_inode = btrfs_delete_inode,
.put_super = btrfs_put_super,
.read_inode = btrfs_read_locked_inode,
.write_super = btrfs_write_super,
.sync_fs = btrfs_sync_fs,
.write_inode = btrfs_write_inode,
.dirty_inode = btrfs_dirty_inode,
.alloc_inode = btrfs_alloc_inode,
.destroy_inode = btrfs_destroy_inode,
.statfs = btrfs_statfs,
};
static struct inode_operations btrfs_dir_inode_operations = {
.lookup = btrfs_lookup,
.create = btrfs_create,
.unlink = btrfs_unlink,
.link = btrfs_link,
.mkdir = btrfs_mkdir,
.rmdir = btrfs_rmdir,
.rename = btrfs_rename,
.symlink = btrfs_symlink,
.setattr = btrfs_setattr,
};
static struct inode_operations btrfs_dir_ro_inode_operations = {
.lookup = btrfs_lookup,
};
static struct file_operations btrfs_dir_file_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = btrfs_readdir,
.ioctl = btrfs_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = btrfs_compat_ioctl,
#endif
};
static struct address_space_operations btrfs_aops = {
.readpage = btrfs_readpage,
.writepage = btrfs_writepage,
.sync_page = block_sync_page,
.prepare_write = btrfs_prepare_write,
.commit_write = btrfs_commit_write,
.bmap = btrfs_bmap,
};
static struct address_space_operations btrfs_symlink_aops = {
.readpage = btrfs_readpage,
.writepage = btrfs_writepage,
};
static struct inode_operations btrfs_file_inode_operations = {
.truncate = btrfs_truncate,
.getattr = btrfs_getattr,
.setattr = btrfs_setattr,
};
static struct file_operations btrfs_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.aio_read = btrfs_file_aio_read,
.write = btrfs_file_write,
.mmap = generic_file_mmap,
.open = generic_file_open,
.ioctl = btrfs_ioctl,
.fsync = btrfs_sync_file,
#ifdef CONFIG_COMPAT
.compat_ioctl = btrfs_compat_ioctl,
#endif
};
static struct inode_operations btrfs_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = page_follow_link_light,
.put_link = page_put_link,
};
static int __init init_btrfs_fs(void)
{
int err;
printk("btrfs loaded!\n");
btrfs_init_transaction_sys();
err = init_inodecache();
if (err)
return err;
return register_filesystem(&btrfs_fs_type);
destroy_inodecache();
return err;
}
static void __exit exit_btrfs_fs(void)
{
btrfs_exit_transaction_sys();
destroy_inodecache();
unregister_filesystem(&btrfs_fs_type);
printk("btrfs unloaded\n");
}
module_init(init_btrfs_fs)
module_exit(exit_btrfs_fs)
MODULE_LICENSE("GPL");
Ссылка в новой задаче Показать git blame Копировать постоянную ссылку