[net-next-2.6.git] / fs / sysv / ialloc.c

/*
 *  linux/fs/sysv/ialloc.c
 *
 *  minix/bitmap.c
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  ext/freelists.c
 *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
 *
 *  xenix/alloc.c
 *  Copyright (C) 1992  Doug Evans
 *
 *  coh/alloc.c
 *  Copyright (C) 1993  Pascal Haible, Bruno Haible
 *
 *  sysv/ialloc.c
 *  Copyright (C) 1993  Bruno Haible
 *
 *  This file contains code for allocating/freeing inodes.
 */

#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include "sysv.h"

/* We don't trust the value of
   sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
   but we nevertheless keep it up to date. */

/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */

/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
static inline sysv_ino_t *
sv_sb_fic_inode(struct super_block * sb, unsigned int i)
{
	struct sysv_sb_info *sbi = SYSV_SB(sb);

	if (sbi->s_bh1 == sbi->s_bh2)
		return &sbi->s_sb_fic_inodes[i];
	else {
		/* 512 byte Xenix FS */
		unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
		if (offset < 512)
			return (sysv_ino_t*)(sbi->s_sbd1 + offset);
		else
			return (sysv_ino_t*)(sbi->s_sbd2 + offset);
	}
}

struct sysv_inode *
sysv_raw_inode(struct super_block *sb, unsigned ino, struct buffer_head **bh)
{
	struct sysv_sb_info *sbi = SYSV_SB(sb);
	struct sysv_inode *res;
	int block = sbi->s_firstinodezone + sbi->s_block_base;

	block += (ino-1) >> sbi->s_inodes_per_block_bits;
	*bh = sb_bread(sb, block);
	if (!*bh)
		return NULL;
	res = (struct sysv_inode *)(*bh)->b_data;
	return res + ((ino-1) & sbi->s_inodes_per_block_1);
}

static int refill_free_cache(struct super_block *sb)
{
	struct sysv_sb_info *sbi = SYSV_SB(sb);
	struct buffer_head * bh;
	struct sysv_inode * raw_inode;
	int i = 0, ino;

	ino = SYSV_ROOT_INO+1;
	raw_inode = sysv_raw_inode(sb, ino, &bh);
	if (!raw_inode)
		goto out;
	while (ino <= sbi->s_ninodes) {
		if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) {
			*sv_sb_fic_inode(sb,i++) = cpu_to_fs16(SYSV_SB(sb), ino);
			if (i == sbi->s_fic_size)
				break;
		}
		if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
			brelse(bh);
			raw_inode = sysv_raw_inode(sb, ino, &bh);
			if (!raw_inode)
				goto out;
		} else
			raw_inode++;
	}
	brelse(bh);
out:
	return i;
}

void sysv_free_inode(struct inode * inode)
{
	struct super_block *sb = inode->i_sb;
	struct sysv_sb_info *sbi = SYSV_SB(sb);
	unsigned int ino;
	struct buffer_head * bh;
	struct sysv_inode * raw_inode;
	unsigned count;

	sb = inode->i_sb;
	ino = inode->i_ino;
	if (ino <= SYSV_ROOT_INO || ino > sbi->s_ninodes) {
		printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
		return;
	}
	raw_inode = sysv_raw_inode(sb, ino, &bh);
	clear_inode(inode);
	if (!raw_inode) {
		printk("sysv_free_inode: unable to read inode block on device "
		       "%s\n", inode->i_sb->s_id);
		return;
	}
	lock_super(sb);
	count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
	if (count < sbi->s_fic_size) {
		*sv_sb_fic_inode(sb,count++) = cpu_to_fs16(sbi, ino);
		*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
	}
	fs16_add(sbi, sbi->s_sb_total_free_inodes, 1);
	dirty_sb(sb);
	memset(raw_inode, 0, sizeof(struct sysv_inode));
	mark_buffer_dirty(bh);
	unlock_super(sb);
	brelse(bh);
}

struct inode * sysv_new_inode(const struct inode * dir, mode_t mode)
{
	struct super_block *sb = dir->i_sb;
	struct sysv_sb_info *sbi = SYSV_SB(sb);
	struct inode *inode;
	sysv_ino_t ino;
	unsigned count;
	struct writeback_control wbc = {
		.sync_mode = WB_SYNC_NONE
	};

	inode = new_inode(sb);
	if (!inode)
		return ERR_PTR(-ENOMEM);

	lock_super(sb);
	count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
	if (count == 0 || (*sv_sb_fic_inode(sb,count-1) == 0)) {
		count = refill_free_cache(sb);
		if (count == 0) {
			iput(inode);
			unlock_super(sb);
			return ERR_PTR(-ENOSPC);
		}
	}
	/* Now count > 0. */
	ino = *sv_sb_fic_inode(sb,--count);
	*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
	fs16_add(sbi, sbi->s_sb_total_free_inodes, -1);
	dirty_sb(sb);
	inode_init_owner(inode, dir, mode);
	inode->i_ino = fs16_to_cpu(sbi, ino);
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
	inode->i_blocks = 0;
	memset(SYSV_I(inode)->i_data, 0, sizeof(SYSV_I(inode)->i_data));
	SYSV_I(inode)->i_dir_start_lookup = 0;
	insert_inode_hash(inode);
	mark_inode_dirty(inode);

	sysv_write_inode(inode, &wbc);	/* ensure inode not allocated again */
	mark_inode_dirty(inode);	/* cleared by sysv_write_inode() */
	/* That's it. */
	unlock_super(sb);
	return inode;
}

unsigned long sysv_count_free_inodes(struct super_block * sb)
{
	struct sysv_sb_info *sbi = SYSV_SB(sb);
	struct buffer_head * bh;
	struct sysv_inode * raw_inode;
	int ino, count, sb_count;

	lock_super(sb);

	sb_count = fs16_to_cpu(sbi, *sbi->s_sb_total_free_inodes);

	if (0)
		goto trust_sb;

	/* this causes a lot of disk traffic ... */
	count = 0;
	ino = SYSV_ROOT_INO+1;
	raw_inode = sysv_raw_inode(sb, ino, &bh);
	if (!raw_inode)
		goto Eio;
	while (ino <= sbi->s_ninodes) {
		if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
			count++;
		if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
			brelse(bh);
			raw_inode = sysv_raw_inode(sb, ino, &bh);
			if (!raw_inode)
				goto Eio;
		} else
			raw_inode++;
	}
	brelse(bh);
	if (count != sb_count)
		goto Einval;
out:
	unlock_super(sb);
	return count;

Einval:
	printk("sysv_count_free_inodes: "
		"free inode count was %d, correcting to %d\n",
		sb_count, count);
	if (!(sb->s_flags & MS_RDONLY)) {
		*sbi->s_sb_total_free_inodes = cpu_to_fs16(SYSV_SB(sb), count);
		dirty_sb(sb);
	}
	goto out;

Eio:
	printk("sysv_count_free_inodes: unable to read inode table\n");
trust_sb:
	count = sb_count;
	goto out;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/sysv/ialloc.c
	3	*
	4	* minix/bitmap.c
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* ext/freelists.c
	8	* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
	9	*
	10	* xenix/alloc.c
	11	* Copyright (C) 1992 Doug Evans
	12	*
	13	* coh/alloc.c
	14	* Copyright (C) 1993 Pascal Haible, Bruno Haible
	15	*
	16	* sysv/ialloc.c
	17	* Copyright (C) 1993 Bruno Haible
	18	*
	19	* This file contains code for allocating/freeing inodes.
	20	*/
	21
	22	#include <linux/kernel.h>
	23	#include <linux/stddef.h>
	24	#include <linux/sched.h>
	25	#include <linux/stat.h>
	26	#include <linux/string.h>
	27	#include <linux/buffer_head.h>
46c23d7f	28	#include <linux/writeback.h>
1da177e4 LT	29	#include "sysv.h"
	30
	31	/* We don't trust the value of
	32	sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
	33	but we nevertheless keep it up to date. */
	34
	35	/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */
	36
	37	/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
	38	static inline sysv_ino_t *
	39	sv_sb_fic_inode(struct super_block * sb, unsigned int i)
	40	{
	41	struct sysv_sb_info *sbi = SYSV_SB(sb);
	42
	43	if (sbi->s_bh1 == sbi->s_bh2)
	44	return &sbi->s_sb_fic_inodes[i];
	45	else {
	46	/* 512 byte Xenix FS */
	47	unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
	48	if (offset < 512)
	49	return (sysv_ino_t*)(sbi->s_sbd1 + offset);
	50	else
	51	return (sysv_ino_t*)(sbi->s_sbd2 + offset);
	52	}
	53	}
	54
	55	struct sysv_inode *
	56	sysv_raw_inode(struct super_block sb, unsigned ino, struct buffer_head *bh)
	57	{
	58	struct sysv_sb_info *sbi = SYSV_SB(sb);
	59	struct sysv_inode *res;
	60	int block = sbi->s_firstinodezone + sbi->s_block_base;
	61
	62	block += (ino-1) >> sbi->s_inodes_per_block_bits;
	63	*bh = sb_bread(sb, block);
	64	if (!*bh)
	65	return NULL;
	66	res = (struct sysv_inode )(bh)->b_data;
	67	return res + ((ino-1) & sbi->s_inodes_per_block_1);
	68	}
	69
	70	static int refill_free_cache(struct super_block *sb)
	71	{
	72	struct sysv_sb_info *sbi = SYSV_SB(sb);
	73	struct buffer_head * bh;
	74	struct sysv_inode * raw_inode;
	75	int i = 0, ino;
	76
	77	ino = SYSV_ROOT_INO+1;
	78	raw_inode = sysv_raw_inode(sb, ino, &bh);
	79	if (!raw_inode)
	80	goto out;
	81	while (ino <= sbi->s_ninodes) {
	82	if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) {
	83	*sv_sb_fic_inode(sb,i++) = cpu_to_fs16(SYSV_SB(sb), ino);
	84	if (i == sbi->s_fic_size)
	85	break;
	86	}
	87	if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
	88	brelse(bh);
	89	raw_inode = sysv_raw_inode(sb, ino, &bh);
	90	if (!raw_inode)
	91	goto out;
	92	} else
93	raw_inode++;
94	}
95	brelse(bh);
96	out:
97	return i;
98	}
99
100	void sysv_free_inode(struct inode * inode)
101	{
102	struct super_block *sb = inode->i_sb;
103	struct sysv_sb_info *sbi = SYSV_SB(sb);
104	unsigned int ino;
105	struct buffer_head * bh;
106	struct sysv_inode * raw_inode;
107	unsigned count;
108
109	sb = inode->i_sb;
110	ino = inode->i_ino;
111	if (ino <= SYSV_ROOT_INO \|\| ino > sbi->s_ninodes) {
112	printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
113	return;
114	}
115	raw_inode = sysv_raw_inode(sb, ino, &bh);
116	clear_inode(inode);
117	if (!raw_inode) {
118	printk("sysv_free_inode: unable to read inode block on device "
119	"%s\n", inode->i_sb->s_id);
120	return;
121	}
122	lock_super(sb);
123	count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
124	if (count < sbi->s_fic_size) {
125	*sv_sb_fic_inode(sb,count++) = cpu_to_fs16(sbi, ino);
126	*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
127	}
128	fs16_add(sbi, sbi->s_sb_total_free_inodes, 1);
129	dirty_sb(sb);
130	memset(raw_inode, 0, sizeof(struct sysv_inode));
131	mark_buffer_dirty(bh);
132	unlock_super(sb);
133	brelse(bh);
134	}
135
136	struct inode * sysv_new_inode(const struct inode * dir, mode_t mode)
137	{
138	struct super_block *sb = dir->i_sb;
139	struct sysv_sb_info *sbi = SYSV_SB(sb);
140	struct inode *inode;
141	sysv_ino_t ino;
142	unsigned count;
46c23d7f LR	143	struct writeback_control wbc = {
	144	.sync_mode = WB_SYNC_NONE
	145	};
1da177e4 LT	146
	147	inode = new_inode(sb);
	148	if (!inode)
	149	return ERR_PTR(-ENOMEM);
	150
	151	lock_super(sb);
	152	count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
	153	if (count == 0 \|\| (*sv_sb_fic_inode(sb,count-1) == 0)) {
	154	count = refill_free_cache(sb);
	155	if (count == 0) {
	156	iput(inode);
	157	unlock_super(sb);
	158	return ERR_PTR(-ENOSPC);
	159	}
	160	}
	161	/* Now count > 0. */
	162	ino = *sv_sb_fic_inode(sb,--count);
	163	*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
	164	fs16_add(sbi, sbi->s_sb_total_free_inodes, -1);
	165	dirty_sb(sb);
85640bd9	166	inode_init_owner(inode, dir, mode);
1da177e4 LT	167	inode->i_ino = fs16_to_cpu(sbi, ino);
1da177e4 LT	168	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
ba52de12	169	inode->i_blocks = 0;
1da177e4 LT	170	memset(SYSV_I(inode)->i_data, 0, sizeof(SYSV_I(inode)->i_data));
	171	SYSV_I(inode)->i_dir_start_lookup = 0;
	172	insert_inode_hash(inode);
	173	mark_inode_dirty(inode);
	174
46c23d7f	175	sysv_write_inode(inode, &wbc); /* ensure inode not allocated again */
1da177e4 LT	176	mark_inode_dirty(inode); /* cleared by sysv_write_inode() */
	177	/* That's it. */
	178	unlock_super(sb);
	179	return inode;
	180	}
	181
	182	unsigned long sysv_count_free_inodes(struct super_block * sb)
	183	{
	184	struct sysv_sb_info *sbi = SYSV_SB(sb);
	185	struct buffer_head * bh;
	186	struct sysv_inode * raw_inode;
	187	int ino, count, sb_count;
	188
	189	lock_super(sb);
	190
	191	sb_count = fs16_to_cpu(sbi, *sbi->s_sb_total_free_inodes);
	192
	193	if (0)
	194	goto trust_sb;
	195
	196	/* this causes a lot of disk traffic ... */
	197	count = 0;
	198	ino = SYSV_ROOT_INO+1;
	199	raw_inode = sysv_raw_inode(sb, ino, &bh);
	200	if (!raw_inode)
	201	goto Eio;
	202	while (ino <= sbi->s_ninodes) {
	203	if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
	204	count++;
	205	if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
	206	brelse(bh);
	207	raw_inode = sysv_raw_inode(sb, ino, &bh);
	208	if (!raw_inode)
	209	goto Eio;
	210	} else
	211	raw_inode++;
	212	}
	213	brelse(bh);
	214	if (count != sb_count)
	215	goto Einval;
	216	out:
	217	unlock_super(sb);
	218	return count;
	219
	220	Einval:
	221	printk("sysv_count_free_inodes: "
	222	"free inode count was %d, correcting to %d\n",
	223	sb_count, count);
	224	if (!(sb->s_flags & MS_RDONLY)) {
	225	*sbi->s_sb_total_free_inodes = cpu_to_fs16(SYSV_SB(sb), count);
	226	dirty_sb(sb);
	227	}
	228	goto out;
	229
	230	Eio:
	231	printk("sysv_count_free_inodes: unable to read inode table\n");
	232	trust_sb:
	233	count = sb_count;
	234	goto out;
	235	}