[linux.git] / fs / omfs / file.c

/*
 * OMFS (as used by RIO Karma) file operations.
 * Copyright (C) 2005 Bob Copeland <[email protected]>
 * 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 u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset)
{
	return (sbi->s_sys_blocksize - offset -
		sizeof(struct omfs_extent)) /
		sizeof(struct omfs_extent_entry) + 1;
}

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;
	u32 max_extents;
	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]);
	max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);

	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);

		if (extent_count > max_extents)
			goto out_brelse;

		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]);
		max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
	}
	ret = 0;
out:
	return ret;
out_brelse:
	brelse(bh);
	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 = omfs_max_extents(sbi, OMFS_EXTENT_START);

	/* 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;
	u32 max_extents;
	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]);
	max_extents = omfs_max_extents(sbi, 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;

		if (extent_count > max_extents)
			goto out_brelse;

		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]);
		max_extents = omfs_max_extents(sbi, 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);
}

const 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 = simple_fsync,
	.splice_read = generic_file_splice_read,
};

const struct inode_operations omfs_file_inops = {
	.truncate = omfs_truncate
};

const 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 <[email protected]>
	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
9419fc1c BC	14	static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset)
	15	{
	16	return (sbi->s_sys_blocksize - offset -
	17	sizeof(struct omfs_extent)) /
	18	sizeof(struct omfs_extent_entry) + 1;
	19	}
	20
8f09e987 BC	21	void omfs_make_empty_table(struct buffer_head *bh, int offset)
	22	{
	23	struct omfs_extent oe = (struct omfs_extent ) &bh->b_data[offset];
	24
d406f66d	25	oe->e_next = ~cpu_to_be64(0ULL);
8f09e987 BC	26	oe->e_extent_count = cpu_to_be32(1),
8f09e987 BC	27	oe->e_fill = cpu_to_be32(0x22),
d406f66d HH	28	oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);
d406f66d HH	29	oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);
8f09e987 BC	30	}
	31
	32	int omfs_shrink_inode(struct inode *inode)
	33	{
	34	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
	35	struct omfs_extent *oe;
	36	struct omfs_extent_entry *entry;
	37	struct buffer_head *bh;
	38	u64 next, last;
	39	u32 extent_count;
9419fc1c	40	u32 max_extents;
8f09e987 BC	41	int ret;
	42
	43	/* traverse extent table, freeing each entry that is greater
	44	* than inode->i_size;
	45	*/
	46	next = inode->i_ino;
	47
	48	/* only support truncate -> 0 for now */
	49	ret = -EIO;
	50	if (inode->i_size != 0)
	51	goto out;
	52
	53	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
	54	if (!bh)
	55	goto out;
	56
	57	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
9419fc1c	58	max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
8f09e987 BC	59
	60	for (;;) {
	61
9419fc1c BC	62	if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
9419fc1c BC	63	goto out_brelse;
8f09e987 BC	64
8f09e987 BC	65	extent_count = be32_to_cpu(oe->e_extent_count);
9419fc1c BC	66
	67	if (extent_count > max_extents)
	68	goto out_brelse;
	69
8f09e987 BC	70	last = next;
	71	next = be64_to_cpu(oe->e_next);
	72	entry = &oe->e_entry;
	73
	74	/* ignore last entry as it is the terminator */
	75	for (; extent_count > 1; extent_count--) {
	76	u64 start, count;
	77	start = be64_to_cpu(entry->e_cluster);
	78	count = be64_to_cpu(entry->e_blocks);
	79
	80	omfs_clear_range(inode->i_sb, start, (int) count);
	81	entry++;
	82	}
	83	omfs_make_empty_table(bh, (char *) oe - bh->b_data);
	84	mark_buffer_dirty(bh);
	85	brelse(bh);
	86
	87	if (last != inode->i_ino)
	88	omfs_clear_range(inode->i_sb, last, sbi->s_mirrors);
	89
	90	if (next == ~0)
	91	break;
	92
	93	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
	94	if (!bh)
	95	goto out;
	96	oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
9419fc1c	97	max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
8f09e987 BC	98	}
	99	ret = 0;
	100	out:
	101	return ret;
9419fc1c BC	102	out_brelse:
	103	brelse(bh);
	104	return ret;
8f09e987 BC	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	}
9419fc1c	157	max_count = omfs_max_extents(sbi, OMFS_EXTENT_START);
8f09e987 BC	158
	159	/* TODO: add a continuation block here */
	160	if (be32_to_cpu(oe->e_extent_count) > max_count-1)
	161	return -EIO;
	162
	163	/* try to allocate a new cluster */
	164	ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize,
	165	&new_block, &new_count);
	166	if (ret)
	167	goto out_fail;
	168
	169	/* copy terminator down an entry */
	170	entry = terminator;
	171	terminator++;
	172	memcpy(terminator, entry, sizeof(struct omfs_extent_entry));
	173
	174	entry->e_cluster = cpu_to_be64(new_block);
	175	entry->e_blocks = cpu_to_be64((u64) new_count);
	176
	177	terminator->e_blocks = ~(cpu_to_be64(
	178	be64_to_cpu(~terminator->e_blocks) + (u64) new_count));
	179
	180	/* write in new entry */
	181	oe->e_extent_count = cpu_to_be32(1 + be32_to_cpu(oe->e_extent_count));
	182
	183	out:
	184	*ret_block = new_block;
	185	out_fail:
	186	return ret;
	187	}
	188
	189	/*
	190	* Scans across the directory table for a given file block number.
	191	* If block not found, return 0.
	192	*/
	193	static sector_t find_block(struct inode inode, struct omfs_extent_entry ent,
	194	sector_t block, int count, int *left)
	195	{
	196	/* count > 1 because of terminator */
	197	sector_t searched = 0;
	198	for (; count > 1; count--) {
	199	int numblocks = clus_to_blk(OMFS_SB(inode->i_sb),
	200	be64_to_cpu(ent->e_blocks));
	201
	202	if (block >= searched &&
	203	block < searched + numblocks) {
	204	/*
	205	* found it at cluster + (block - searched)
	206	* numblocks - (block - searched) is remainder
	207	*/
	208	*left = numblocks - (block - searched);
	209	return clus_to_blk(OMFS_SB(inode->i_sb),
	210	be64_to_cpu(ent->e_cluster)) +
	211	block - searched;
	212	}
	213	searched += numblocks;
	214	ent++;
	215	}
	216	return 0;
	217	}
	218
	219	static int omfs_get_block(struct inode *inode, sector_t block,
	220	struct buffer_head *bh_result, int create)
	221	{
222	struct buffer_head *bh;
223	sector_t next, offset;
224	int ret;
225	u64 new_block;
9419fc1c	226	u32 max_extents;
8f09e987 BC	227	int extent_count;
	228	struct omfs_extent *oe;
	229	struct omfs_extent_entry *entry;
	230	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
	231	int max_blocks = bh_result->b_size >> inode->i_blkbits;
	232	int remain;
	233
	234	ret = -EIO;
	235	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, inode->i_ino));
	236	if (!bh)
	237	goto out;
	238
	239	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
9419fc1c	240	max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
8f09e987 BC	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
9419fc1c BC	252	if (extent_count > max_extents)
	253	goto out_brelse;
	254
8f09e987 BC	255	offset = find_block(inode, entry, block, extent_count, &remain);
	256	if (offset > 0) {
	257	ret = 0;
	258	map_bh(bh_result, inode->i_sb, offset);
	259	if (remain > max_blocks)
	260	remain = max_blocks;
	261	bh_result->b_size = (remain << inode->i_blkbits);
	262	goto out_brelse;
	263	}
	264	if (next == ~0)
	265	break;
	266
	267	brelse(bh);
	268	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
	269	if (!bh)
	270	goto out;
	271	oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
9419fc1c	272	max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
8f09e987 BC	273	}
	274	if (create) {
	275	ret = omfs_grow_extent(inode, oe, &new_block);
	276	if (ret == 0) {
	277	mark_buffer_dirty(bh);
	278	mark_inode_dirty(inode);
	279	map_bh(bh_result, inode->i_sb,
	280	clus_to_blk(sbi, new_block));
	281	}
	282	}
	283	out_brelse:
	284	brelse(bh);
	285	out:
	286	return ret;
	287	}
	288
	289	static int omfs_readpage(struct file file, struct page page)
	290	{
	291	return block_read_full_page(page, omfs_get_block);
	292	}
	293
	294	static int omfs_readpages(struct file file, struct address_space mapping,
	295	struct list_head *pages, unsigned nr_pages)
	296	{
	297	return mpage_readpages(mapping, pages, nr_pages, omfs_get_block);
	298	}
	299
	300	static int omfs_writepage(struct page page, struct writeback_control wbc)
	301	{
	302	return block_write_full_page(page, omfs_get_block, wbc);
	303	}
	304
	305	static int
	306	omfs_writepages(struct address_space mapping, struct writeback_control wbc)
	307	{
	308	return mpage_writepages(mapping, wbc, omfs_get_block);
	309	}
	310
	311	static int omfs_write_begin(struct file file, struct address_space mapping,
	312	loff_t pos, unsigned len, unsigned flags,
	313	struct page pagep, void fsdata)
	314	{
	315	*pagep = NULL;
	316	return block_write_begin(file, mapping, pos, len, flags,
	317	pagep, fsdata, omfs_get_block);
	318	}
	319
	320	static sector_t omfs_bmap(struct address_space *mapping, sector_t block)
	321	{
	322	return generic_block_bmap(mapping, block, omfs_get_block);
	323	}
	324
828c0950	325	const struct file_operations omfs_file_operations = {
8f09e987 BC	326	.llseek = generic_file_llseek,
	327	.read = do_sync_read,
	328	.write = do_sync_write,
	329	.aio_read = generic_file_aio_read,
	330	.aio_write = generic_file_aio_write,
	331	.mmap = generic_file_mmap,
bea6b64c	332	.fsync = simple_fsync,
8f09e987 BC	333	.splice_read = generic_file_splice_read,
	334	};
	335
6e1d5dcc	336	const struct inode_operations omfs_file_inops = {
8f09e987 BC	337	.truncate = omfs_truncate
	338	};
	339
7f09410b	340	const struct address_space_operations omfs_aops = {
8f09e987 BC	341	.readpage = omfs_readpage,
	342	.readpages = omfs_readpages,
	343	.writepage = omfs_writepage,
	344	.writepages = omfs_writepages,
	345	.sync_page = block_sync_page,
	346	.write_begin = omfs_write_begin,
	347	.write_end = generic_write_end,
	348	.bmap = omfs_bmap,
	349	};
	350