1 #include <linux/module.h>
3 #include <linux/blkdev.h>
4 #include <linux/crypto.h>
5 #include <linux/scatterlist.h>
8 #include "transaction.h"
11 static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
13 struct btrfs_node *node = btrfs_buffer_node(buf);
14 if (buf->b_blocknr != btrfs_header_blocknr(&node->header)) {
17 if (root->node && btrfs_header_parentid(&node->header) !=
18 btrfs_header_parentid(btrfs_buffer_header(root->node))) {
24 struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr)
26 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
27 int blockbits = root->fs_info->sb->s_blocksize_bits;
28 unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
30 struct buffer_head *bh;
31 struct buffer_head *head;
32 struct buffer_head *ret = NULL;
34 page = find_lock_page(mapping, index);
38 if (!page_has_buffers(page))
41 head = page_buffers(page);
44 if (buffer_mapped(bh) && bh->b_blocknr == blocknr) {
53 page_cache_release(page);
57 struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
60 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
61 int blockbits = root->fs_info->sb->s_blocksize_bits;
62 unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
64 struct buffer_head *bh;
65 struct buffer_head *head;
66 struct buffer_head *ret = NULL;
67 u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
68 page = grab_cache_page(mapping, index);
72 if (!page_has_buffers(page))
73 create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
74 head = page_buffers(page);
77 if (!buffer_mapped(bh)) {
78 bh->b_bdev = root->fs_info->sb->s_bdev;
79 bh->b_blocknr = first_block;
80 set_buffer_mapped(bh);
82 if (bh->b_blocknr == blocknr) {
92 page_cache_release(page);
96 static sector_t max_block(struct block_device *bdev)
98 sector_t retval = ~((sector_t)0);
99 loff_t sz = i_size_read(bdev->bd_inode);
102 unsigned int size = block_size(bdev);
103 unsigned int sizebits = blksize_bits(size);
104 retval = (sz >> sizebits);
109 static int btree_get_block(struct inode *inode, sector_t iblock,
110 struct buffer_head *bh, int create)
112 if (iblock >= max_block(inode->i_sb->s_bdev)) {
117 * for reads, we're just trying to fill a partial page.
118 * return a hole, they will have to call get_block again
119 * before they can fill it, and they will get -EIO at that
124 bh->b_bdev = inode->i_sb->s_bdev;
125 bh->b_blocknr = iblock;
126 set_buffer_mapped(bh);
130 static int csum_tree_block(struct btrfs_root * root, struct buffer_head *bh,
133 struct btrfs_node *node = btrfs_buffer_node(bh);
134 struct scatterlist sg;
135 struct crypto_hash *tfm = root->fs_info->hash_tfm;
136 struct hash_desc desc;
142 sg_init_one(&sg, bh->b_data + 32, bh->b_size - 32);
143 spin_lock(&root->fs_info->hash_lock);
144 ret = crypto_hash_digest(&desc, &sg, bh->b_size - 32, result);
145 spin_unlock(&root->fs_info->hash_lock);
147 printk("sha256 digest failed\n");
150 if (memcmp(node->header.csum, result, sizeof(result)))
151 printk("csum verify failed on %Lu\n", bh->b_blocknr);
154 memcpy(node->header.csum, result, sizeof(node->header.csum));
158 static int btree_writepage(struct page *page, struct writeback_control *wbc)
160 struct buffer_head *bh;
161 struct btrfs_root *root = btrfs_sb(page->mapping->host->i_sb);
162 struct buffer_head *head;
164 if (!page_has_buffers(page)) {
165 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
166 (1 << BH_Dirty)|(1 << BH_Uptodate));
168 head = page_buffers(page);
171 if (buffer_dirty(bh))
172 csum_tree_block(root, bh, 0);
173 bh = bh->b_this_page;
174 } while (bh != head);
175 return block_write_full_page(page, btree_get_block, wbc);
178 static int btree_readpage(struct file * file, struct page * page)
180 return block_read_full_page(page, btree_get_block);
183 static struct address_space_operations btree_aops = {
184 .readpage = btree_readpage,
185 .writepage = btree_writepage,
186 .sync_page = block_sync_page,
189 struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
191 struct buffer_head *bh = NULL;
193 bh = btrfs_find_create_tree_block(root, blocknr);
197 if (!buffer_uptodate(bh)) {
199 bh->b_end_io = end_buffer_read_sync;
202 if (!buffer_uptodate(bh))
204 csum_tree_block(root, bh, 1);
208 if (check_tree_block(root, bh))
217 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
218 struct buffer_head *buf)
220 mark_buffer_dirty(buf);
224 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
225 struct buffer_head *buf)
227 clear_buffer_dirty(buf);
231 static int __setup_root(struct btrfs_super_block *super,
232 struct btrfs_root *root,
233 struct btrfs_fs_info *fs_info,
237 root->commit_root = NULL;
238 root->blocksize = btrfs_super_blocksize(super);
240 root->fs_info = fs_info;
241 memset(&root->root_key, 0, sizeof(root->root_key));
242 memset(&root->root_item, 0, sizeof(root->root_item));
246 static int find_and_setup_root(struct btrfs_super_block *super,
247 struct btrfs_root *tree_root,
248 struct btrfs_fs_info *fs_info,
250 struct btrfs_root *root)
254 __setup_root(super, root, fs_info, objectid);
255 ret = btrfs_find_last_root(tree_root, objectid,
256 &root->root_item, &root->root_key);
259 root->node = read_tree_block(root,
260 btrfs_root_blocknr(&root->root_item));
265 struct btrfs_root *open_ctree(struct super_block *sb,
266 struct buffer_head *sb_buffer,
267 struct btrfs_super_block *disk_super)
269 struct btrfs_root *root = kmalloc(sizeof(struct btrfs_root),
271 struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
273 struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
275 struct btrfs_root *inode_root = kmalloc(sizeof(struct btrfs_root),
277 struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
281 if (!btrfs_super_root(disk_super)) {
284 init_bit_radix(&fs_info->pinned_radix);
285 init_bit_radix(&fs_info->pending_del_radix);
286 sb_set_blocksize(sb, sb_buffer->b_size);
287 fs_info->running_transaction = NULL;
288 fs_info->fs_root = root;
289 fs_info->tree_root = tree_root;
290 fs_info->extent_root = extent_root;
291 fs_info->inode_root = inode_root;
292 fs_info->last_inode_alloc = 0;
293 fs_info->last_inode_alloc_dirid = 0;
294 fs_info->disk_super = disk_super;
296 fs_info->btree_inode = new_inode(sb);
297 fs_info->btree_inode->i_ino = 1;
298 fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
299 fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
300 mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
301 fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
302 spin_lock_init(&fs_info->hash_lock);
304 if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) {
305 printk("failed to allocate sha256 hash\n");
309 mutex_init(&fs_info->trans_mutex);
310 mutex_init(&fs_info->fs_mutex);
311 memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
312 memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
314 __setup_root(disk_super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID);
316 fs_info->sb_buffer = read_tree_block(tree_root, sb_buffer->b_blocknr);
318 if (!fs_info->sb_buffer) {
324 disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
325 fs_info->disk_super = disk_super;
327 tree_root->node = read_tree_block(tree_root,
328 btrfs_super_root(disk_super));
329 BUG_ON(!tree_root->node);
331 ret = find_and_setup_root(disk_super, tree_root, fs_info,
332 BTRFS_EXTENT_TREE_OBJECTID, extent_root);
335 ret = find_and_setup_root(disk_super, tree_root, fs_info,
336 BTRFS_INODE_MAP_OBJECTID, inode_root);
339 ret = find_and_setup_root(disk_super, tree_root, fs_info,
340 BTRFS_FS_TREE_OBJECTID, root);
342 root->commit_root = root->node;
345 root->fs_info->generation = root->root_key.offset + 1;
349 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
352 struct buffer_head *bh = root->fs_info->sb_buffer;
353 btrfs_set_super_root(root->fs_info->disk_super,
354 root->fs_info->tree_root->node->b_blocknr);
356 clear_buffer_dirty(bh);
357 csum_tree_block(root, bh, 0);
358 bh->b_end_io = end_buffer_write_sync;
360 submit_bh(WRITE, bh);
362 if (!buffer_uptodate(bh)) {
369 int close_ctree(struct btrfs_root *root)
372 struct btrfs_trans_handle *trans;
374 trans = btrfs_start_transaction(root, 1);
375 btrfs_commit_transaction(trans, root);
376 /* run commit again to drop the original snapshot */
377 trans = btrfs_start_transaction(root, 1);
378 btrfs_commit_transaction(trans, root);
379 ret = btrfs_write_and_wait_transaction(NULL, root);
381 write_ctree_super(NULL, root);
384 btrfs_block_release(root, root->node);
385 if (root->fs_info->extent_root->node)
386 btrfs_block_release(root->fs_info->extent_root,
387 root->fs_info->extent_root->node);
388 if (root->fs_info->inode_root->node)
389 btrfs_block_release(root->fs_info->inode_root,
390 root->fs_info->inode_root->node);
391 if (root->fs_info->tree_root->node)
392 btrfs_block_release(root->fs_info->tree_root,
393 root->fs_info->tree_root->node);
394 btrfs_block_release(root, root->commit_root);
395 btrfs_block_release(root, root->fs_info->sb_buffer);
396 crypto_free_hash(root->fs_info->hash_tfm);
397 truncate_inode_pages(root->fs_info->btree_inode->i_mapping, 0);
398 iput(root->fs_info->btree_inode);
399 kfree(root->fs_info->extent_root);
400 kfree(root->fs_info->inode_root);
401 kfree(root->fs_info->tree_root);
402 kfree(root->fs_info);
407 void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)