[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / omfs / file.c

/*
 * OMFS (as used by RIO Karma) file operations.
 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
 * Released under GPL v2.
 */

#include <linux/version.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include "omfs.h"

static int omfs_sync_file(struct file *file, struct dentry *dentry,
		int datasync)
{
	struct inode *inode = dentry->d_inode;
	int err;

	err = sync_mapping_buffers(inode->i_mapping);
	if (!(inode->i_state & I_DIRTY))
		return err;
	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
		return err;
	err |= omfs_sync_inode(inode);
	return err ? -EIO : 0;
}

void omfs_make_empty_table(struct buffer_head *bh, int offset)
{
	struct omfs_extent *oe = (struct omfs_extent *) &bh->b_data[offset];

	oe->e_next = ~cpu_to_be64(0ULL);
	oe->e_extent_count = cpu_to_be32(1),
	oe->e_fill = cpu_to_be32(0x22),
	oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);
	oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);
}

int omfs_shrink_inode(struct inode *inode)
{
	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
	struct omfs_extent *oe;
	struct omfs_extent_entry *entry;
	struct buffer_head *bh;
	u64 next, last;
	u32 extent_count;
	int ret;

	/* traverse extent table, freeing each entry that is greater
	 * than inode->i_size;
	 */
	next = inode->i_ino;

	/* only support truncate -> 0 for now */
	ret = -EIO;
	if (inode->i_size != 0)
		goto out;

	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
	if (!bh)
		goto out;

	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);

	for (;;) {

		if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) {
			brelse(bh);
			goto out;
		}

		extent_count = be32_to_cpu(oe->e_extent_count);
		last = next;
		next = be64_to_cpu(oe->e_next);
		entry = &oe->e_entry;

		/* ignore last entry as it is the terminator */
		for (; extent_count > 1; extent_count--) {
			u64 start, count;
			start = be64_to_cpu(entry->e_cluster);
			count = be64_to_cpu(entry->e_blocks);

			omfs_clear_range(inode->i_sb, start, (int) count);
			entry++;
		}
		omfs_make_empty_table(bh, (char *) oe - bh->b_data);
		mark_buffer_dirty(bh);
		brelse(bh);

		if (last != inode->i_ino)
			omfs_clear_range(inode->i_sb, last, sbi->s_mirrors);

		if (next == ~0)
			break;

		bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
		if (!bh)
			goto out;
		oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
	}
	ret = 0;
out:
	return ret;
}

static void omfs_truncate(struct inode *inode)
{
	omfs_shrink_inode(inode);
	mark_inode_dirty(inode);
}

/*
 * Add new blocks to the current extent, or create new entries/continuations
 * as necessary.
 */
static int omfs_grow_extent(struct inode *inode, struct omfs_extent *oe,
			u64 *ret_block)
{
	struct omfs_extent_entry *terminator;
	struct omfs_extent_entry *entry = &oe->e_entry;
	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
	u32 extent_count = be32_to_cpu(oe->e_extent_count);
	u64 new_block = 0;
	u32 max_count;
	int new_count;
	int ret = 0;

	/* reached the end of the extent table with no blocks mapped.
	 * there are three possibilities for adding: grow last extent,
	 * add a new extent to the current extent table, and add a
	 * continuation inode.  in last two cases need an allocator for
	 * sbi->s_cluster_size
	 */

	/* TODO: handle holes */

	/* should always have a terminator */
	if (extent_count < 1)
		return -EIO;

	/* trivially grow current extent, if next block is not taken */
	terminator = entry + extent_count - 1;
	if (extent_count > 1) {
		entry = terminator-1;
		new_block = be64_to_cpu(entry->e_cluster) +
			be64_to_cpu(entry->e_blocks);

		if (omfs_allocate_block(inode->i_sb, new_block)) {
			entry->e_blocks =
				cpu_to_be64(be64_to_cpu(entry->e_blocks) + 1);
			terminator->e_blocks = ~(cpu_to_be64(
				be64_to_cpu(~terminator->e_blocks) + 1));
			goto out;
		}
	}
	max_count = (sbi->s_sys_blocksize - OMFS_EXTENT_START -
		sizeof(struct omfs_extent)) /
		sizeof(struct omfs_extent_entry) + 1;

	/* TODO: add a continuation block here */
	if (be32_to_cpu(oe->e_extent_count) > max_count-1)
		return -EIO;

	/* try to allocate a new cluster */
	ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize,
		&new_block, &new_count);
	if (ret)
		goto out_fail;

	/* copy terminator down an entry */
	entry = terminator;
	terminator++;
	memcpy(terminator, entry, sizeof(struct omfs_extent_entry));

	entry->e_cluster = cpu_to_be64(new_block);
	entry->e_blocks = cpu_to_be64((u64) new_count);

	terminator->e_blocks = ~(cpu_to_be64(
		be64_to_cpu(~terminator->e_blocks) + (u64) new_count));

	/* write in new entry */
	oe->e_extent_count = cpu_to_be32(1 + be32_to_cpu(oe->e_extent_count));

out:
	*ret_block = new_block;
out_fail:
	return ret;
}

/*
 * Scans across the directory table for a given file block number.
 * If block not found, return 0.
 */
static sector_t find_block(struct inode *inode, struct omfs_extent_entry *ent,
			sector_t block, int count, int *left)
{
	/* count > 1 because of terminator */
	sector_t searched = 0;
	for (; count > 1; count--) {
		int numblocks = clus_to_blk(OMFS_SB(inode->i_sb),
			be64_to_cpu(ent->e_blocks));

		if (block >= searched  &&
		    block < searched + numblocks) {
			/*
			 * found it at cluster + (block - searched)
			 * numblocks - (block - searched) is remainder
			 */
			*left = numblocks - (block - searched);
			return clus_to_blk(OMFS_SB(inode->i_sb),
				be64_to_cpu(ent->e_cluster)) +
				block - searched;
		}
		searched += numblocks;
		ent++;
	}
	return 0;
}

static int omfs_get_block(struct inode *inode, sector_t block,
			  struct buffer_head *bh_result, int create)
{
	struct buffer_head *bh;
	sector_t next, offset;
	int ret;
	u64 new_block;
	int extent_count;
	struct omfs_extent *oe;
	struct omfs_extent_entry *entry;
	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
	int max_blocks = bh_result->b_size >> inode->i_blkbits;
	int remain;

	ret = -EIO;
	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, inode->i_ino));
	if (!bh)
		goto out;

	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
	next = inode->i_ino;

	for (;;) {

		if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
			goto out_brelse;

		extent_count = be32_to_cpu(oe->e_extent_count);
		next = be64_to_cpu(oe->e_next);
		entry = &oe->e_entry;

		offset = find_block(inode, entry, block, extent_count, &remain);
		if (offset > 0) {
			ret = 0;
			map_bh(bh_result, inode->i_sb, offset);
			if (remain > max_blocks)
				remain = max_blocks;
			bh_result->b_size = (remain << inode->i_blkbits);
			goto out_brelse;
		}
		if (next == ~0)
			break;

		brelse(bh);
		bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
		if (!bh)
			goto out;
		oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
	}
	if (create) {
		ret = omfs_grow_extent(inode, oe, &new_block);
		if (ret == 0) {
			mark_buffer_dirty(bh);
			mark_inode_dirty(inode);
			map_bh(bh_result, inode->i_sb,
					clus_to_blk(sbi, new_block));
		}
	}
out_brelse:
	brelse(bh);
out:
	return ret;
}

static int omfs_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page, omfs_get_block);
}

static int omfs_readpages(struct file *file, struct address_space *mapping,
		struct list_head *pages, unsigned nr_pages)
{
	return mpage_readpages(mapping, pages, nr_pages, omfs_get_block);
}

static int omfs_writepage(struct page *page, struct writeback_control *wbc)
{
	return block_write_full_page(page, omfs_get_block, wbc);
}

static int
omfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
	return mpage_writepages(mapping, wbc, omfs_get_block);
}

static int omfs_write_begin(struct file *file, struct address_space *mapping,
			loff_t pos, unsigned len, unsigned flags,
			struct page **pagep, void **fsdata)
{
	*pagep = NULL;
	return block_write_begin(file, mapping, pos, len, flags,
				pagep, fsdata, omfs_get_block);
}

static sector_t omfs_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping, block, omfs_get_block);
}

struct file_operations omfs_file_operations = {
	.llseek = generic_file_llseek,
	.read = do_sync_read,
	.write = do_sync_write,
	.aio_read = generic_file_aio_read,
	.aio_write = generic_file_aio_write,
	.mmap = generic_file_mmap,
	.fsync = omfs_sync_file,
	.splice_read = generic_file_splice_read,
};

struct inode_operations omfs_file_inops = {
	.truncate = omfs_truncate
};

struct address_space_operations omfs_aops = {
	.readpage = omfs_readpage,
	.readpages = omfs_readpages,
	.writepage = omfs_writepage,
	.writepages = omfs_writepages,
	.sync_page = block_sync_page,
	.write_begin = omfs_write_begin,
	.write_end = generic_write_end,
	.bmap = omfs_bmap,
};
Commit	Line	Data
8f09e987 BC	1	/*
	2	* OMFS (as used by RIO Karma) file operations.
	3	* Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
	4	* Released under GPL v2.
	5	*/
	6
	7	#include <linux/version.h>
	8	#include <linux/module.h>
	9	#include <linux/fs.h>
	10	#include <linux/buffer_head.h>
	11	#include <linux/mpage.h>
	12	#include "omfs.h"
	13
	14	static int omfs_sync_file(struct file file, struct dentry dentry,
	15	int datasync)
	16	{
	17	struct inode *inode = dentry->d_inode;
	18	int err;
	19
	20	err = sync_mapping_buffers(inode->i_mapping);
	21	if (!(inode->i_state & I_DIRTY))
	22	return err;
	23	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
	24	return err;
	25	err \|= omfs_sync_inode(inode);
	26	return err ? -EIO : 0;
	27	}
	28
	29	void omfs_make_empty_table(struct buffer_head *bh, int offset)
	30	{
	31	struct omfs_extent oe = (struct omfs_extent ) &bh->b_data[offset];
	32
d406f66d	33	oe->e_next = ~cpu_to_be64(0ULL);
8f09e987 BC	34	oe->e_extent_count = cpu_to_be32(1),
8f09e987 BC	35	oe->e_fill = cpu_to_be32(0x22),
d406f66d HH	36	oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);
d406f66d HH	37	oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);
8f09e987 BC	38	}
	39
	40	int omfs_shrink_inode(struct inode *inode)
	41	{
	42	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
	43	struct omfs_extent *oe;
	44	struct omfs_extent_entry *entry;
	45	struct buffer_head *bh;
	46	u64 next, last;
	47	u32 extent_count;
	48	int ret;
	49
	50	/* traverse extent table, freeing each entry that is greater
	51	* than inode->i_size;
	52	*/
	53	next = inode->i_ino;
	54
	55	/* only support truncate -> 0 for now */
	56	ret = -EIO;
	57	if (inode->i_size != 0)
	58	goto out;
	59
	60	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
	61	if (!bh)
	62	goto out;
	63
	64	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
	65
	66	for (;;) {
	67
	68	if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) {
	69	brelse(bh);
	70	goto out;
	71	}
	72
	73	extent_count = be32_to_cpu(oe->e_extent_count);
	74	last = next;
	75	next = be64_to_cpu(oe->e_next);
	76	entry = &oe->e_entry;
	77
	78	/* ignore last entry as it is the terminator */
	79	for (; extent_count > 1; extent_count--) {
	80	u64 start, count;
	81	start = be64_to_cpu(entry->e_cluster);
	82	count = be64_to_cpu(entry->e_blocks);
	83
	84	omfs_clear_range(inode->i_sb, start, (int) count);
	85	entry++;
	86	}
	87	omfs_make_empty_table(bh, (char *) oe - bh->b_data);
	88	mark_buffer_dirty(bh);
	89	brelse(bh);
	90
	91	if (last != inode->i_ino)
	92	omfs_clear_range(inode->i_sb, last, sbi->s_mirrors);
	93
	94	if (next == ~0)
	95	break;
	96
	97	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
	98	if (!bh)
	99	goto out;
	100	oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
	101	}
102	ret = 0;
103	out:
104	return ret;
105	}
106
107	static void omfs_truncate(struct inode *inode)
108	{
109	omfs_shrink_inode(inode);
110	mark_inode_dirty(inode);
111	}
112
113	/*
114	* Add new blocks to the current extent, or create new entries/continuations
115	* as necessary.
116	*/
117	static int omfs_grow_extent(struct inode inode, struct omfs_extent oe,
118	u64 *ret_block)
119	{
120	struct omfs_extent_entry *terminator;
121	struct omfs_extent_entry *entry = &oe->e_entry;
122	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
123	u32 extent_count = be32_to_cpu(oe->e_extent_count);
124	u64 new_block = 0;
125	u32 max_count;
126	int new_count;
127	int ret = 0;
128
129	/* reached the end of the extent table with no blocks mapped.
130	* there are three possibilities for adding: grow last extent,
131	* add a new extent to the current extent table, and add a
132	* continuation inode. in last two cases need an allocator for
133	* sbi->s_cluster_size
134	*/
135
136	/* TODO: handle holes */
137
138	/* should always have a terminator */
139	if (extent_count < 1)
140	return -EIO;
141
142	/* trivially grow current extent, if next block is not taken */
143	terminator = entry + extent_count - 1;
144	if (extent_count > 1) {
145	entry = terminator-1;
146	new_block = be64_to_cpu(entry->e_cluster) +
147	be64_to_cpu(entry->e_blocks);
148
149	if (omfs_allocate_block(inode->i_sb, new_block)) {
150	entry->e_blocks =
151	cpu_to_be64(be64_to_cpu(entry->e_blocks) + 1);
152	terminator->e_blocks = ~(cpu_to_be64(
153	be64_to_cpu(~terminator->e_blocks) + 1));
154	goto out;
155	}
156	}
157	max_count = (sbi->s_sys_blocksize - OMFS_EXTENT_START -
158	sizeof(struct omfs_extent)) /
159	sizeof(struct omfs_extent_entry) + 1;
160
161	/* TODO: add a continuation block here */
162	if (be32_to_cpu(oe->e_extent_count) > max_count-1)
163	return -EIO;
164
165	/* try to allocate a new cluster */
166	ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize,
167	&new_block, &new_count);
168	if (ret)
169	goto out_fail;
170
171	/* copy terminator down an entry */
172	entry = terminator;
173	terminator++;
174	memcpy(terminator, entry, sizeof(struct omfs_extent_entry));
175
176	entry->e_cluster = cpu_to_be64(new_block);
177	entry->e_blocks = cpu_to_be64((u64) new_count);
178
179	terminator->e_blocks = ~(cpu_to_be64(
180	be64_to_cpu(~terminator->e_blocks) + (u64) new_count));
181
182	/* write in new entry */
183	oe->e_extent_count = cpu_to_be32(1 + be32_to_cpu(oe->e_extent_count));
184
185	out:
186	*ret_block = new_block;
187	out_fail:
188	return ret;
189	}
190
191	/*
192	* Scans across the directory table for a given file block number.
193	* If block not found, return 0.
194	*/
195	static sector_t find_block(struct inode inode, struct omfs_extent_entry ent,
196	sector_t block, int count, int *left)
197	{
198	/* count > 1 because of terminator */
199	sector_t searched = 0;
200	for (; count > 1; count--) {
201	int numblocks = clus_to_blk(OMFS_SB(inode->i_sb),
202	be64_to_cpu(ent->e_blocks));
203
204	if (block >= searched &&
205	block < searched + numblocks) {
206	/*
207	* found it at cluster + (block - searched)
208	* numblocks - (block - searched) is remainder
209	*/
210	*left = numblocks - (block - searched);
211	return clus_to_blk(OMFS_SB(inode->i_sb),
212	be64_to_cpu(ent->e_cluster)) +
213	block - searched;
214	}
215	searched += numblocks;
216	ent++;
217	}
218	return 0;
219	}
220
221	static int omfs_get_block(struct inode *inode, sector_t block,
222	struct buffer_head *bh_result, int create)
223	{
224	struct buffer_head *bh;
225	sector_t next, offset;
226	int ret;
227	u64 new_block;
228	int extent_count;
229	struct omfs_extent *oe;
230	struct omfs_extent_entry *entry;
231	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
232	int max_blocks = bh_result->b_size >> inode->i_blkbits;
233	int remain;
234
235	ret = -EIO;
236	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, inode->i_ino));
237	if (!bh)
238	goto out;
239
240	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
241	next = inode->i_ino;
242
243	for (;;) {
244
245	if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
246	goto out_brelse;
247
248	extent_count = be32_to_cpu(oe->e_extent_count);
249	next = be64_to_cpu(oe->e_next);
250	entry = &oe->e_entry;
251
252	offset = find_block(inode, entry, block, extent_count, &remain);
253	if (offset > 0) {
254	ret = 0;
255	map_bh(bh_result, inode->i_sb, offset);
256	if (remain > max_blocks)
257	remain = max_blocks;
258	bh_result->b_size = (remain << inode->i_blkbits);
259	goto out_brelse;
260	}
261	if (next == ~0)
262	break;
263
264	brelse(bh);
265	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
266	if (!bh)
267	goto out;
268	oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
269	}
270	if (create) {
271	ret = omfs_grow_extent(inode, oe, &new_block);
272	if (ret == 0) {
273	mark_buffer_dirty(bh);
274	mark_inode_dirty(inode);
275	map_bh(bh_result, inode->i_sb,
276	clus_to_blk(sbi, new_block));
277	}
278	}
279	out_brelse:
280	brelse(bh);
281	out:
282	return ret;
283	}
284
285	static int omfs_readpage(struct file file, struct page page)
286	{
287	return block_read_full_page(page, omfs_get_block);
288	}
289
290	static int omfs_readpages(struct file file, struct address_space mapping,
291	struct list_head *pages, unsigned nr_pages)
292	{
293	return mpage_readpages(mapping, pages, nr_pages, omfs_get_block);
294	}
295
296	static int omfs_writepage(struct page page, struct writeback_control wbc)
297	{
298	return block_write_full_page(page, omfs_get_block, wbc);
299	}
300
301	static int
302	omfs_writepages(struct address_space mapping, struct writeback_control wbc)
303	{
304	return mpage_writepages(mapping, wbc, omfs_get_block);
305	}
306
307	static int omfs_write_begin(struct file file, struct address_space mapping,
308	loff_t pos, unsigned len, unsigned flags,
309	struct page pagep, void fsdata)
310	{
311	*pagep = NULL;
312	return block_write_begin(file, mapping, pos, len, flags,
313	pagep, fsdata, omfs_get_block);
314	}
315
316	static sector_t omfs_bmap(struct address_space *mapping, sector_t block)
317	{
318	return generic_block_bmap(mapping, block, omfs_get_block);
319	}
320
321	struct file_operations omfs_file_operations = {
322	.llseek = generic_file_llseek,
323	.read = do_sync_read,
324	.write = do_sync_write,
325	.aio_read = generic_file_aio_read,
326	.aio_write = generic_file_aio_write,
327	.mmap = generic_file_mmap,
328	.fsync = omfs_sync_file,
329	.splice_read = generic_file_splice_read,
330	};
331
332	struct inode_operations omfs_file_inops = {
333	.truncate = omfs_truncate
334	};
335
336	struct address_space_operations omfs_aops = {
337	.readpage = omfs_readpage,
338	.readpages = omfs_readpages,
339	.writepage = omfs_writepage,
340	.writepages = omfs_writepages,
341	.sync_page = block_sync_page,
342	.write_begin = omfs_write_begin,
343	.write_end = generic_write_end,
344	.bmap = omfs_bmap,
345	};
346