[net-next-2.6.git] / fs / reiserfs / tail_conversion.c

/*
 * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details
 */

#include <linux/config.h>
#include <linux/time.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/reiserfs_fs.h>

/* access to tail : when one is going to read tail it must make sure, that is not running.
 direct2indirect and indirect2direct can not run concurrently */

/* Converts direct items to an unformatted node. Panics if file has no
   tail. -ENOSPC if no disk space for conversion */
/* path points to first direct item of the file regarless of how many of
   them are there */
int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
		    struct path *path, struct buffer_head *unbh,
		    loff_t tail_offset)
{
	struct super_block *sb = inode->i_sb;
	struct buffer_head *up_to_date_bh;
	struct item_head *p_le_ih = PATH_PITEM_HEAD(path);
	unsigned long total_tail = 0;
	struct cpu_key end_key;	/* Key to search for the last byte of the
				   converted item. */
	struct item_head ind_ih;	/* new indirect item to be inserted or
					   key of unfm pointer to be pasted */
	int n_blk_size, n_retval;	/* returned value for reiserfs_insert_item and clones */
	unp_t unfm_ptr;		/* Handle on an unformatted node
				   that will be inserted in the
				   tree. */

	BUG_ON(!th->t_trans_id);

	REISERFS_SB(sb)->s_direct2indirect++;

	n_blk_size = sb->s_blocksize;

	/* and key to search for append or insert pointer to the new
	   unformatted node. */
	copy_item_head(&ind_ih, p_le_ih);
	set_le_ih_k_offset(&ind_ih, tail_offset);
	set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);

	/* Set the key to search for the place for new unfm pointer */
	make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);

	// FIXME: we could avoid this 
	if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
		reiserfs_warning(sb, "PAP-14030: direct2indirect: "
				 "pasted or inserted byte exists in the tree %K. "
				 "Use fsck to repair.", &end_key);
		pathrelse(path);
		return -EIO;
	}

	p_le_ih = PATH_PITEM_HEAD(path);

	unfm_ptr = cpu_to_le32(unbh->b_blocknr);

	if (is_statdata_le_ih(p_le_ih)) {
		/* Insert new indirect item. */
		set_ih_free_space(&ind_ih, 0);	/* delete at nearest future */
		put_ih_item_len(&ind_ih, UNFM_P_SIZE);
		PATH_LAST_POSITION(path)++;
		n_retval =
		    reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
					 (char *)&unfm_ptr);
	} else {
		/* Paste into last indirect item of an object. */
		n_retval = reiserfs_paste_into_item(th, path, &end_key, inode,
						    (char *)&unfm_ptr,
						    UNFM_P_SIZE);
	}
	if (n_retval) {
		return n_retval;
	}
	// note: from here there are two keys which have matching first
	// three key components. They only differ by the fourth one.

	/* Set the key to search for the direct items of the file */
	make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
		     4);

	/* Move bytes from the direct items to the new unformatted node
	   and delete them. */
	while (1) {
		int tail_size;

		/* end_key.k_offset is set so, that we will always have found
		   last item of the file */
		if (search_for_position_by_key(sb, &end_key, path) ==
		    POSITION_FOUND)
			reiserfs_panic(sb,
				       "PAP-14050: direct2indirect: "
				       "direct item (%K) not found", &end_key);
		p_le_ih = PATH_PITEM_HEAD(path);
		RFALSE(!is_direct_le_ih(p_le_ih),
		       "vs-14055: direct item expected(%K), found %h",
		       &end_key, p_le_ih);
		tail_size = (le_ih_k_offset(p_le_ih) & (n_blk_size - 1))
		    + ih_item_len(p_le_ih) - 1;

		/* we only send the unbh pointer if the buffer is not up to date.
		 ** this avoids overwriting good data from writepage() with old data
		 ** from the disk or buffer cache
		 ** Special case: unbh->b_page will be NULL if we are coming through
		 ** DIRECT_IO handler here.
		 */
		if (!unbh->b_page || buffer_uptodate(unbh)
		    || PageUptodate(unbh->b_page)) {
			up_to_date_bh = NULL;
		} else {
			up_to_date_bh = unbh;
		}
		n_retval = reiserfs_delete_item(th, path, &end_key, inode,
						up_to_date_bh);

		total_tail += n_retval;
		if (tail_size == n_retval)
			// done: file does not have direct items anymore
			break;

	}
	/* if we've copied bytes from disk into the page, we need to zero
	 ** out the unused part of the block (it was not up to date before)
	 */
	if (up_to_date_bh) {
		unsigned pgoff =
		    (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
		char *kaddr = kmap_atomic(up_to_date_bh->b_page, KM_USER0);
		memset(kaddr + pgoff, 0, n_blk_size - total_tail);
		kunmap_atomic(kaddr, KM_USER0);
	}

	REISERFS_I(inode)->i_first_direct_byte = U32_MAX;

	return 0;
}

/* stolen from fs/buffer.c */
void reiserfs_unmap_buffer(struct buffer_head *bh)
{
	lock_buffer(bh);
	if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
		BUG();
	}
	clear_buffer_dirty(bh);
	/* Remove the buffer from whatever list it belongs to. We are mostly
	   interested in removing it from per-sb j_dirty_buffers list, to avoid
	   BUG() on attempt to write not mapped buffer */
	if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
		struct inode *inode = bh->b_page->mapping->host;
		struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
		spin_lock(&j->j_dirty_buffers_lock);
		list_del_init(&bh->b_assoc_buffers);
		reiserfs_free_jh(bh);
		spin_unlock(&j->j_dirty_buffers_lock);
	}
	clear_buffer_mapped(bh);
	clear_buffer_req(bh);
	clear_buffer_new(bh);
	bh->b_bdev = NULL;
	unlock_buffer(bh);
}

/* this first locks inode (neither reads nor sync are permitted),
   reads tail through page cache, insert direct item. When direct item
   inserted successfully inode is left locked. Return value is always
   what we expect from it (number of cut bytes). But when tail remains
   in the unformatted node, we set mode to SKIP_BALANCING and unlock
   inode */
int indirect2direct(struct reiserfs_transaction_handle *th, struct inode *p_s_inode, struct page *page, struct path *p_s_path,	/* path to the indirect item. */
		    const struct cpu_key *p_s_item_key,	/* Key to look for unformatted node pointer to be cut. */
		    loff_t n_new_file_size,	/* New file size. */
		    char *p_c_mode)
{
	struct super_block *p_s_sb = p_s_inode->i_sb;
	struct item_head s_ih;
	unsigned long n_block_size = p_s_sb->s_blocksize;
	char *tail;
	int tail_len, round_tail_len;
	loff_t pos, pos1;	/* position of first byte of the tail */
	struct cpu_key key;

	BUG_ON(!th->t_trans_id);

	REISERFS_SB(p_s_sb)->s_indirect2direct++;

	*p_c_mode = M_SKIP_BALANCING;

	/* store item head path points to. */
	copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));

	tail_len = (n_new_file_size & (n_block_size - 1));
	if (get_inode_sd_version(p_s_inode) == STAT_DATA_V2)
		round_tail_len = ROUND_UP(tail_len);
	else
		round_tail_len = tail_len;

	pos =
	    le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
					 1) * p_s_sb->s_blocksize;
	pos1 = pos;

	// we are protected by i_mutex. The tail can not disapper, not
	// append can be done either
	// we are in truncate or packing tail in file_release

	tail = (char *)kmap(page);	/* this can schedule */

	if (path_changed(&s_ih, p_s_path)) {
		/* re-search indirect item */
		if (search_for_position_by_key(p_s_sb, p_s_item_key, p_s_path)
		    == POSITION_NOT_FOUND)
			reiserfs_panic(p_s_sb,
				       "PAP-5520: indirect2direct: "
				       "item to be converted %K does not exist",
				       p_s_item_key);
		copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
#ifdef CONFIG_REISERFS_CHECK
		pos = le_ih_k_offset(&s_ih) - 1 +
		    (ih_item_len(&s_ih) / UNFM_P_SIZE -
		     1) * p_s_sb->s_blocksize;
		if (pos != pos1)
			reiserfs_panic(p_s_sb, "vs-5530: indirect2direct: "
				       "tail position changed while we were reading it");
#endif
	}

	/* Set direct item header to insert. */
	make_le_item_head(&s_ih, NULL, get_inode_item_key_version(p_s_inode),
			  pos1 + 1, TYPE_DIRECT, round_tail_len,
			  0xffff /*ih_free_space */ );

	/* we want a pointer to the first byte of the tail in the page.
	 ** the page was locked and this part of the page was up to date when
	 ** indirect2direct was called, so we know the bytes are still valid
	 */
	tail = tail + (pos & (PAGE_CACHE_SIZE - 1));

	PATH_LAST_POSITION(p_s_path)++;

	key = *p_s_item_key;
	set_cpu_key_k_type(&key, TYPE_DIRECT);
	key.key_length = 4;
	/* Insert tail as new direct item in the tree */
	if (reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode,
				 tail ? tail : NULL) < 0) {
		/* No disk memory. So we can not convert last unformatted node
		   to the direct item.  In this case we used to adjust
		   indirect items's ih_free_space. Now ih_free_space is not
		   used, it would be ideal to write zeros to corresponding
		   unformatted node. For now i_size is considered as guard for
		   going out of file size */
		kunmap(page);
		return n_block_size - round_tail_len;
	}
	kunmap(page);

	/* make sure to get the i_blocks changes from reiserfs_insert_item */
	reiserfs_update_sd(th, p_s_inode);

	// note: we have now the same as in above direct2indirect
	// conversion: there are two keys which have matching first three
	// key components. They only differ by the fouhth one.

	/* We have inserted new direct item and must remove last
	   unformatted node. */
	*p_c_mode = M_CUT;

	/* we store position of first direct item in the in-core inode */
	//mark_file_with_tail (p_s_inode, pos1 + 1);
	REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1;

	return n_block_size - round_tail_len;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details
	3	*/
	4
	5	#include <linux/config.h>
	6	#include <linux/time.h>
	7	#include <linux/pagemap.h>
	8	#include <linux/buffer_head.h>
	9	#include <linux/reiserfs_fs.h>
	10
	11	/* access to tail : when one is going to read tail it must make sure, that is not running.
	12	direct2indirect and indirect2direct can not run concurrently */
	13
1da177e4 LT	14	/* Converts direct items to an unformatted node. Panics if file has no
	15	tail. -ENOSPC if no disk space for conversion */
	16	/* path points to first direct item of the file regarless of how many of
	17	them are there */
bd4c625c LT	18	int direct2indirect(struct reiserfs_transaction_handle th, struct inode inode,
	19	struct path path, struct buffer_head unbh,
	20	loff_t tail_offset)
1da177e4	21	{
bd4c625c LT	22	struct super_block *sb = inode->i_sb;
	23	struct buffer_head *up_to_date_bh;
	24	struct item_head *p_le_ih = PATH_PITEM_HEAD(path);
	25	unsigned long total_tail = 0;
	26	struct cpu_key end_key; /* Key to search for the last byte of the
	27	converted item. */
	28	struct item_head ind_ih; /* new indirect item to be inserted or
	29	key of unfm pointer to be pasted */
	30	int n_blk_size, n_retval; /* returned value for reiserfs_insert_item and clones */
	31	unp_t unfm_ptr; /* Handle on an unformatted node
	32	that will be inserted in the
	33	tree. */
	34
	35	BUG_ON(!th->t_trans_id);
	36
	37	REISERFS_SB(sb)->s_direct2indirect++;
	38
	39	n_blk_size = sb->s_blocksize;
	40
	41	/* and key to search for append or insert pointer to the new
	42	unformatted node. */
	43	copy_item_head(&ind_ih, p_le_ih);
	44	set_le_ih_k_offset(&ind_ih, tail_offset);
	45	set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
	46
	47	/* Set the key to search for the place for new unfm pointer */
	48	make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
	49
	50	// FIXME: we could avoid this
	51	if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
	52	reiserfs_warning(sb, "PAP-14030: direct2indirect: "
	53	"pasted or inserted byte exists in the tree %K. "
	54	"Use fsck to repair.", &end_key);
	55	pathrelse(path);
	56	return -EIO;
	57	}
	58
	59	p_le_ih = PATH_PITEM_HEAD(path);
	60
	61	unfm_ptr = cpu_to_le32(unbh->b_blocknr);
	62
	63	if (is_statdata_le_ih(p_le_ih)) {
	64	/* Insert new indirect item. */
	65	set_ih_free_space(&ind_ih, 0); /* delete at nearest future */
	66	put_ih_item_len(&ind_ih, UNFM_P_SIZE);
	67	PATH_LAST_POSITION(path)++;
	68	n_retval =
	69	reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
1da177e4	70	(char *)&unfm_ptr);
1da177e4	71	} else {
bd4c625c LT	72	/* Paste into last indirect item of an object. */
	73	n_retval = reiserfs_paste_into_item(th, path, &end_key, inode,
	74	(char *)&unfm_ptr,
	75	UNFM_P_SIZE);
1da177e4	76	}
bd4c625c LT	77	if (n_retval) {
	78	return n_retval;
	79	}
	80	// note: from here there are two keys which have matching first
	81	// three key components. They only differ by the fourth one.
	82
	83	/* Set the key to search for the direct items of the file */
	84	make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
	85	4);
	86
	87	/* Move bytes from the direct items to the new unformatted node
	88	and delete them. */
	89	while (1) {
	90	int tail_size;
	91
	92	/* end_key.k_offset is set so, that we will always have found
	93	last item of the file */
	94	if (search_for_position_by_key(sb, &end_key, path) ==
	95	POSITION_FOUND)
	96	reiserfs_panic(sb,
	97	"PAP-14050: direct2indirect: "
	98	"direct item (%K) not found", &end_key);
	99	p_le_ih = PATH_PITEM_HEAD(path);
	100	RFALSE(!is_direct_le_ih(p_le_ih),
	101	"vs-14055: direct item expected(%K), found %h",
	102	&end_key, p_le_ih);
	103	tail_size = (le_ih_k_offset(p_le_ih) & (n_blk_size - 1))
	104	+ ih_item_len(p_le_ih) - 1;
	105
	106	/* we only send the unbh pointer if the buffer is not up to date.
	107	** this avoids overwriting good data from writepage() with old data
	108	** from the disk or buffer cache
	109	** Special case: unbh->b_page will be NULL if we are coming through
	110	** DIRECT_IO handler here.
	111	*/
	112	if (!unbh->b_page \|\| buffer_uptodate(unbh)
	113	\|\| PageUptodate(unbh->b_page)) {
	114	up_to_date_bh = NULL;
	115	} else {
	116	up_to_date_bh = unbh;
	117	}
	118	n_retval = reiserfs_delete_item(th, path, &end_key, inode,
	119	up_to_date_bh);
	120
	121	total_tail += n_retval;
	122	if (tail_size == n_retval)
	123	// done: file does not have direct items anymore
	124	break;
1da177e4	125
bd4c625c LT	126	}
	127	/* if we've copied bytes from disk into the page, we need to zero
	128	** out the unused part of the block (it was not up to date before)
	129	*/
	130	if (up_to_date_bh) {
	131	unsigned pgoff =
	132	(tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
	133	char *kaddr = kmap_atomic(up_to_date_bh->b_page, KM_USER0);
	134	memset(kaddr + pgoff, 0, n_blk_size - total_tail);
	135	kunmap_atomic(kaddr, KM_USER0);
	136	}
	137
	138	REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
	139
	140	return 0;
	141	}
1da177e4 LT	142
1da177e4 LT	143	/* stolen from fs/buffer.c */
bd4c625c LT	144	void reiserfs_unmap_buffer(struct buffer_head *bh)
	145	{
	146	lock_buffer(bh);
	147	if (buffer_journaled(bh) \|\| buffer_journal_dirty(bh)) {
	148	BUG();
	149	}
	150	clear_buffer_dirty(bh);
	151	/* Remove the buffer from whatever list it belongs to. We are mostly
	152	interested in removing it from per-sb j_dirty_buffers list, to avoid
	153	BUG() on attempt to write not mapped buffer */
	154	if ((!list_empty(&bh->b_assoc_buffers) \|\| bh->b_private) && bh->b_page) {
	155	struct inode *inode = bh->b_page->mapping->host;
	156	struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
	157	spin_lock(&j->j_dirty_buffers_lock);
	158	list_del_init(&bh->b_assoc_buffers);
	159	reiserfs_free_jh(bh);
	160	spin_unlock(&j->j_dirty_buffers_lock);
	161	}
	162	clear_buffer_mapped(bh);
	163	clear_buffer_req(bh);
	164	clear_buffer_new(bh);
	165	bh->b_bdev = NULL;
	166	unlock_buffer(bh);
1da177e4 LT	167	}
	168
	169	/* this first locks inode (neither reads nor sync are permitted),
	170	reads tail through page cache, insert direct item. When direct item
	171	inserted successfully inode is left locked. Return value is always
	172	what we expect from it (number of cut bytes). But when tail remains
	173	in the unformatted node, we set mode to SKIP_BALANCING and unlock
	174	inode */
bd4c625c LT	175	int indirect2direct(struct reiserfs_transaction_handle th, struct inode p_s_inode, struct page page, struct path p_s_path, /* path to the indirect item. */
	176	const struct cpu_key p_s_item_key, / Key to look for unformatted node pointer to be cut. */
	177	loff_t n_new_file_size, /* New file size. */
	178	char *p_c_mode)
1da177e4	179	{
bd4c625c LT	180	struct super_block *p_s_sb = p_s_inode->i_sb;
	181	struct item_head s_ih;
	182	unsigned long n_block_size = p_s_sb->s_blocksize;
	183	char *tail;
	184	int tail_len, round_tail_len;
	185	loff_t pos, pos1; /* position of first byte of the tail */
	186	struct cpu_key key;
1da177e4	187
bd4c625c	188	BUG_ON(!th->t_trans_id);
1da177e4	189
bd4c625c	190	REISERFS_SB(p_s_sb)->s_indirect2direct++;
1da177e4	191
bd4c625c	192	*p_c_mode = M_SKIP_BALANCING;
1da177e4	193
bd4c625c	194	/* store item head path points to. */
1da177e4	195	copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
bd4c625c LT	196
	197	tail_len = (n_new_file_size & (n_block_size - 1));
	198	if (get_inode_sd_version(p_s_inode) == STAT_DATA_V2)
	199	round_tail_len = ROUND_UP(tail_len);
	200	else
	201	round_tail_len = tail_len;
	202
	203	pos =
	204	le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
	205	1) * p_s_sb->s_blocksize;
	206	pos1 = pos;
	207
1b1dcc1b	208	// we are protected by i_mutex. The tail can not disapper, not
bd4c625c LT	209	// append can be done either
	210	// we are in truncate or packing tail in file_release
	211
	212	tail = (char )kmap(page); / this can schedule */
	213
	214	if (path_changed(&s_ih, p_s_path)) {
	215	/* re-search indirect item */
	216	if (search_for_position_by_key(p_s_sb, p_s_item_key, p_s_path)
	217	== POSITION_NOT_FOUND)
	218	reiserfs_panic(p_s_sb,
	219	"PAP-5520: indirect2direct: "
	220	"item to be converted %K does not exist",
	221	p_s_item_key);
	222	copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
1da177e4	223	#ifdef CONFIG_REISERFS_CHECK
bd4c625c LT	224	pos = le_ih_k_offset(&s_ih) - 1 +
	225	(ih_item_len(&s_ih) / UNFM_P_SIZE -
	226	1) * p_s_sb->s_blocksize;
	227	if (pos != pos1)
	228	reiserfs_panic(p_s_sb, "vs-5530: indirect2direct: "
	229	"tail position changed while we were reading it");
1da177e4	230	#endif
bd4c625c	231	}
1da177e4	232
bd4c625c LT	233	/* Set direct item header to insert. */
	234	make_le_item_head(&s_ih, NULL, get_inode_item_key_version(p_s_inode),
	235	pos1 + 1, TYPE_DIRECT, round_tail_len,
	236	0xffff /ih_free_space / );
	237
	238	/* we want a pointer to the first byte of the tail in the page.
	239	** the page was locked and this part of the page was up to date when
	240	** indirect2direct was called, so we know the bytes are still valid
	241	*/
	242	tail = tail + (pos & (PAGE_CACHE_SIZE - 1));
	243
	244	PATH_LAST_POSITION(p_s_path)++;
	245
	246	key = *p_s_item_key;
	247	set_cpu_key_k_type(&key, TYPE_DIRECT);
	248	key.key_length = 4;
	249	/* Insert tail as new direct item in the tree */
	250	if (reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode,
	251	tail ? tail : NULL) < 0) {
	252	/* No disk memory. So we can not convert last unformatted node
	253	to the direct item. In this case we used to adjust
	254	indirect items's ih_free_space. Now ih_free_space is not
	255	used, it would be ideal to write zeros to corresponding
	256	unformatted node. For now i_size is considered as guard for
	257	going out of file size */
	258	kunmap(page);
	259	return n_block_size - round_tail_len;
	260	}
	261	kunmap(page);
1da177e4	262
bd4c625c LT	263	/* make sure to get the i_blocks changes from reiserfs_insert_item */
bd4c625c LT	264	reiserfs_update_sd(th, p_s_inode);
1da177e4	265
bd4c625c LT	266	// note: we have now the same as in above direct2indirect
	267	// conversion: there are two keys which have matching first three
	268	// key components. They only differ by the fouhth one.
1da177e4	269
bd4c625c LT	270	/* We have inserted new direct item and must remove last
	271	unformatted node. */
	272	*p_c_mode = M_CUT;
1da177e4	273
bd4c625c LT	274	/* we store position of first direct item in the in-core inode */
	275	//mark_file_with_tail (p_s_inode, pos1 + 1);
	276	REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1;
1da177e4	277
bd4c625c LT	278	return n_block_size - round_tail_len;
bd4c625c LT	279	}