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/fs/hfs/btree.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 366 lines | 314 code | 37 blank | 15 comment | 39 complexity | 7a4a86a95610a3853b55937467acdfaf MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  1/*
  2 *  linux/fs/hfs/btree.c
  3 *
  4 * Copyright (C) 2001
  5 * Brad Boyer (flar@allandria.com)
  6 * (C) 2003 Ardis Technologies <roman@ardistech.com>
  7 *
  8 * Handle opening/closing btree
  9 */
 10
 11#include <linux/pagemap.h>
 12#include <linux/slab.h>
 13#include <linux/log2.h>
 14
 15#include "btree.h"
 16
 17/* Get a reference to a B*Tree and do some initial checks */
 18struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
 19{
 20	struct hfs_btree *tree;
 21	struct hfs_btree_header_rec *head;
 22	struct address_space *mapping;
 23	struct page *page;
 24	unsigned int size;
 25
 26	tree = kzalloc(sizeof(*tree), GFP_KERNEL);
 27	if (!tree)
 28		return NULL;
 29
 30	mutex_init(&tree->tree_lock);
 31	spin_lock_init(&tree->hash_lock);
 32	/* Set the correct compare function */
 33	tree->sb = sb;
 34	tree->cnid = id;
 35	tree->keycmp = keycmp;
 36
 37	tree->inode = iget_locked(sb, id);
 38	if (!tree->inode)
 39		goto free_tree;
 40	BUG_ON(!(tree->inode->i_state & I_NEW));
 41	{
 42	struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
 43	HFS_I(tree->inode)->flags = 0;
 44	mutex_init(&HFS_I(tree->inode)->extents_lock);
 45	switch (id) {
 46	case HFS_EXT_CNID:
 47		hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
 48				    mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
 49		if (HFS_I(tree->inode)->alloc_blocks >
 50					HFS_I(tree->inode)->first_blocks) {
 51			printk(KERN_ERR "hfs: invalid btree extent records\n");
 52			unlock_new_inode(tree->inode);
 53			goto free_inode;
 54		}
 55
 56		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
 57		break;
 58	case HFS_CAT_CNID:
 59		hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
 60				    mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
 61
 62		if (!HFS_I(tree->inode)->first_blocks) {
 63			printk(KERN_ERR "hfs: invalid btree extent records "
 64								"(0 size).\n");
 65			unlock_new_inode(tree->inode);
 66			goto free_inode;
 67		}
 68
 69		tree->inode->i_mapping->a_ops = &hfs_btree_aops;
 70		break;
 71	default:
 72		BUG();
 73	}
 74	}
 75	unlock_new_inode(tree->inode);
 76
 77	mapping = tree->inode->i_mapping;
 78	page = read_mapping_page(mapping, 0, NULL);
 79	if (IS_ERR(page))
 80		goto free_inode;
 81
 82	/* Load the header */
 83	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 84	tree->root = be32_to_cpu(head->root);
 85	tree->leaf_count = be32_to_cpu(head->leaf_count);
 86	tree->leaf_head = be32_to_cpu(head->leaf_head);
 87	tree->leaf_tail = be32_to_cpu(head->leaf_tail);
 88	tree->node_count = be32_to_cpu(head->node_count);
 89	tree->free_nodes = be32_to_cpu(head->free_nodes);
 90	tree->attributes = be32_to_cpu(head->attributes);
 91	tree->node_size = be16_to_cpu(head->node_size);
 92	tree->max_key_len = be16_to_cpu(head->max_key_len);
 93	tree->depth = be16_to_cpu(head->depth);
 94
 95	size = tree->node_size;
 96	if (!is_power_of_2(size))
 97		goto fail_page;
 98	if (!tree->node_count)
 99		goto fail_page;
100	switch (id) {
101	case HFS_EXT_CNID:
102		if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
103			printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
104				tree->max_key_len);
105			goto fail_page;
106		}
107		break;
108	case HFS_CAT_CNID:
109		if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
110			printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
111				tree->max_key_len);
112			goto fail_page;
113		}
114		break;
115	default:
116		BUG();
117	}
118
119	tree->node_size_shift = ffs(size) - 1;
120	tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
121
122	kunmap(page);
123	page_cache_release(page);
124	return tree;
125
126fail_page:
127	page_cache_release(page);
128free_inode:
129	tree->inode->i_mapping->a_ops = &hfs_aops;
130	iput(tree->inode);
131free_tree:
132	kfree(tree);
133	return NULL;
134}
135
136/* Release resources used by a btree */
137void hfs_btree_close(struct hfs_btree *tree)
138{
139	struct hfs_bnode *node;
140	int i;
141
142	if (!tree)
143		return;
144
145	for (i = 0; i < NODE_HASH_SIZE; i++) {
146		while ((node = tree->node_hash[i])) {
147			tree->node_hash[i] = node->next_hash;
148			if (atomic_read(&node->refcnt))
149				printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n",
150					node->tree->cnid, node->this, atomic_read(&node->refcnt));
151			hfs_bnode_free(node);
152			tree->node_hash_cnt--;
153		}
154	}
155	iput(tree->inode);
156	kfree(tree);
157}
158
159void hfs_btree_write(struct hfs_btree *tree)
160{
161	struct hfs_btree_header_rec *head;
162	struct hfs_bnode *node;
163	struct page *page;
164
165	node = hfs_bnode_find(tree, 0);
166	if (IS_ERR(node))
167		/* panic? */
168		return;
169	/* Load the header */
170	page = node->page[0];
171	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
172
173	head->root = cpu_to_be32(tree->root);
174	head->leaf_count = cpu_to_be32(tree->leaf_count);
175	head->leaf_head = cpu_to_be32(tree->leaf_head);
176	head->leaf_tail = cpu_to_be32(tree->leaf_tail);
177	head->node_count = cpu_to_be32(tree->node_count);
178	head->free_nodes = cpu_to_be32(tree->free_nodes);
179	head->attributes = cpu_to_be32(tree->attributes);
180	head->depth = cpu_to_be16(tree->depth);
181
182	kunmap(page);
183	set_page_dirty(page);
184	hfs_bnode_put(node);
185}
186
187static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
188{
189	struct hfs_btree *tree = prev->tree;
190	struct hfs_bnode *node;
191	struct hfs_bnode_desc desc;
192	__be32 cnid;
193
194	node = hfs_bnode_create(tree, idx);
195	if (IS_ERR(node))
196		return node;
197
198	if (!tree->free_nodes)
199		panic("FIXME!!!");
200	tree->free_nodes--;
201	prev->next = idx;
202	cnid = cpu_to_be32(idx);
203	hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
204
205	node->type = HFS_NODE_MAP;
206	node->num_recs = 1;
207	hfs_bnode_clear(node, 0, tree->node_size);
208	desc.next = 0;
209	desc.prev = 0;
210	desc.type = HFS_NODE_MAP;
211	desc.height = 0;
212	desc.num_recs = cpu_to_be16(1);
213	desc.reserved = 0;
214	hfs_bnode_write(node, &desc, 0, sizeof(desc));
215	hfs_bnode_write_u16(node, 14, 0x8000);
216	hfs_bnode_write_u16(node, tree->node_size - 2, 14);
217	hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
218
219	return node;
220}
221
222struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
223{
224	struct hfs_bnode *node, *next_node;
225	struct page **pagep;
226	u32 nidx, idx;
227	unsigned off;
228	u16 off16;
229	u16 len;
230	u8 *data, byte, m;
231	int i;
232
233	while (!tree->free_nodes) {
234		struct inode *inode = tree->inode;
235		u32 count;
236		int res;
237
238		res = hfs_extend_file(inode);
239		if (res)
240			return ERR_PTR(res);
241		HFS_I(inode)->phys_size = inode->i_size =
242				(loff_t)HFS_I(inode)->alloc_blocks *
243				HFS_SB(tree->sb)->alloc_blksz;
244		HFS_I(inode)->fs_blocks = inode->i_size >>
245					  tree->sb->s_blocksize_bits;
246		inode_set_bytes(inode, inode->i_size);
247		count = inode->i_size >> tree->node_size_shift;
248		tree->free_nodes = count - tree->node_count;
249		tree->node_count = count;
250	}
251
252	nidx = 0;
253	node = hfs_bnode_find(tree, nidx);
254	if (IS_ERR(node))
255		return node;
256	len = hfs_brec_lenoff(node, 2, &off16);
257	off = off16;
258
259	off += node->page_offset;
260	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
261	data = kmap(*pagep);
262	off &= ~PAGE_CACHE_MASK;
263	idx = 0;
264
265	for (;;) {
266		while (len) {
267			byte = data[off];
268			if (byte != 0xff) {
269				for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
270					if (!(byte & m)) {
271						idx += i;
272						data[off] |= m;
273						set_page_dirty(*pagep);
274						kunmap(*pagep);
275						tree->free_nodes--;
276						mark_inode_dirty(tree->inode);
277						hfs_bnode_put(node);
278						return hfs_bnode_create(tree, idx);
279					}
280				}
281			}
282			if (++off >= PAGE_CACHE_SIZE) {
283				kunmap(*pagep);
284				data = kmap(*++pagep);
285				off = 0;
286			}
287			idx += 8;
288			len--;
289		}
290		kunmap(*pagep);
291		nidx = node->next;
292		if (!nidx) {
293			printk(KERN_DEBUG "hfs: create new bmap node...\n");
294			next_node = hfs_bmap_new_bmap(node, idx);
295		} else
296			next_node = hfs_bnode_find(tree, nidx);
297		hfs_bnode_put(node);
298		if (IS_ERR(next_node))
299			return next_node;
300		node = next_node;
301
302		len = hfs_brec_lenoff(node, 0, &off16);
303		off = off16;
304		off += node->page_offset;
305		pagep = node->page + (off >> PAGE_CACHE_SHIFT);
306		data = kmap(*pagep);
307		off &= ~PAGE_CACHE_MASK;
308	}
309}
310
311void hfs_bmap_free(struct hfs_bnode *node)
312{
313	struct hfs_btree *tree;
314	struct page *page;
315	u16 off, len;
316	u32 nidx;
317	u8 *data, byte, m;
318
319	dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
320	tree = node->tree;
321	nidx = node->this;
322	node = hfs_bnode_find(tree, 0);
323	if (IS_ERR(node))
324		return;
325	len = hfs_brec_lenoff(node, 2, &off);
326	while (nidx >= len * 8) {
327		u32 i;
328
329		nidx -= len * 8;
330		i = node->next;
331		hfs_bnode_put(node);
332		if (!i) {
333			/* panic */;
334			printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
335			return;
336		}
337		node = hfs_bnode_find(tree, i);
338		if (IS_ERR(node))
339			return;
340		if (node->type != HFS_NODE_MAP) {
341			/* panic */;
342			printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
343			hfs_bnode_put(node);
344			return;
345		}
346		len = hfs_brec_lenoff(node, 0, &off);
347	}
348	off += node->page_offset + nidx / 8;
349	page = node->page[off >> PAGE_CACHE_SHIFT];
350	data = kmap(page);
351	off &= ~PAGE_CACHE_MASK;
352	m = 1 << (~nidx & 7);
353	byte = data[off];
354	if (!(byte & m)) {
355		printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
356		kunmap(page);
357		hfs_bnode_put(node);
358		return;
359	}
360	data[off] = byte & ~m;
361	set_page_dirty(page);
362	kunmap(page);
363	hfs_bnode_put(node);
364	tree->free_nodes++;
365	mark_inode_dirty(tree->inode);
366}