[linux.git] / fs / efs / inode.c

/*
 * inode.c
 *
 * Copyright (c) 1999 Al Smith
 *
 * Portions derived from work (c) 1995,1996 Christian Vogelgsang,
 *              and from work (c) 1998 Mike Shaver.
 */

#include <linux/buffer_head.h>
#include <linux/module.h>
#include <linux/fs.h>
#include "efs.h"
#include <linux/efs_fs_sb.h>

static int efs_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page,efs_get_block);
}
static sector_t _efs_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping,block,efs_get_block);
}
static const struct address_space_operations efs_aops = {
	.readpage = efs_readpage,
	.sync_page = block_sync_page,
	.bmap = _efs_bmap
};

static inline void extent_copy(efs_extent *src, efs_extent *dst) {
	/*
	 * this is slightly evil. it doesn't just copy
	 * efs_extent from src to dst, it also mangles
	 * the bits so that dst ends up in cpu byte-order.
	 */

	dst->cooked.ex_magic  =  (unsigned int) src->raw[0];
	dst->cooked.ex_bn     = ((unsigned int) src->raw[1] << 16) |
				((unsigned int) src->raw[2] <<  8) |
				((unsigned int) src->raw[3] <<  0);
	dst->cooked.ex_length =  (unsigned int) src->raw[4];
	dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) |
				((unsigned int) src->raw[6] <<  8) |
				((unsigned int) src->raw[7] <<  0);
	return;
}

struct inode *efs_iget(struct super_block *super, unsigned long ino)
{
	int i, inode_index;
	dev_t device;
	u32 rdev;
	struct buffer_head *bh;
	struct efs_sb_info    *sb = SUPER_INFO(super);
	struct efs_inode_info *in;
	efs_block_t block, offset;
	struct efs_dinode *efs_inode;
	struct inode *inode;

	inode = iget_locked(super, ino);
	if (IS_ERR(inode))
		return ERR_PTR(-ENOMEM);
	if (!(inode->i_state & I_NEW))
		return inode;

	in = INODE_INFO(inode);

	/*
	** EFS layout:
	**
	** |   cylinder group    |   cylinder group    |   cylinder group ..etc
	** |inodes|data          |inodes|data          |inodes|data       ..etc
	**
	** work out the inode block index, (considering initially that the
	** inodes are stored as consecutive blocks). then work out the block
	** number of that inode given the above layout, and finally the
	** offset of the inode within that block.
	*/

	inode_index = inode->i_ino /
		(EFS_BLOCKSIZE / sizeof(struct efs_dinode));

	block = sb->fs_start + sb->first_block + 
		(sb->group_size * (inode_index / sb->inode_blocks)) +
		(inode_index % sb->inode_blocks);

	offset = (inode->i_ino %
			(EFS_BLOCKSIZE / sizeof(struct efs_dinode))) *
		sizeof(struct efs_dinode);

	bh = sb_bread(inode->i_sb, block);
	if (!bh) {
		printk(KERN_WARNING "EFS: bread() failed at block %d\n", block);
		goto read_inode_error;
	}

	efs_inode = (struct efs_dinode *) (bh->b_data + offset);
    
	inode->i_mode  = be16_to_cpu(efs_inode->di_mode);
	inode->i_nlink = be16_to_cpu(efs_inode->di_nlink);
	inode->i_uid   = (uid_t)be16_to_cpu(efs_inode->di_uid);
	inode->i_gid   = (gid_t)be16_to_cpu(efs_inode->di_gid);
	inode->i_size  = be32_to_cpu(efs_inode->di_size);
	inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime);
	inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime);
	inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime);
	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;

	/* this is the number of blocks in the file */
	if (inode->i_size == 0) {
		inode->i_blocks = 0;
	} else {
		inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1;
	}

	rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev);
	if (rdev == 0xffff) {
		rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev);
		if (sysv_major(rdev) > 0xfff)
			device = 0;
		else
			device = MKDEV(sysv_major(rdev), sysv_minor(rdev));
	} else
		device = old_decode_dev(rdev);

	/* get the number of extents for this object */
	in->numextents = be16_to_cpu(efs_inode->di_numextents);
	in->lastextent = 0;

	/* copy the extents contained within the inode to memory */
	for(i = 0; i < EFS_DIRECTEXTENTS; i++) {
		extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i]));
		if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) {
			printk(KERN_WARNING "EFS: extent %d has bad magic number in inode %lu\n", i, inode->i_ino);
			brelse(bh);
			goto read_inode_error;
		}
	}

	brelse(bh);
   
#ifdef DEBUG
	printk(KERN_DEBUG "EFS: efs_iget(): inode %lu, extents %d, mode %o\n",
		inode->i_ino, in->numextents, inode->i_mode);
#endif

	switch (inode->i_mode & S_IFMT) {
		case S_IFDIR: 
			inode->i_op = &efs_dir_inode_operations; 
			inode->i_fop = &efs_dir_operations; 
			break;
		case S_IFREG:
			inode->i_fop = &generic_ro_fops;
			inode->i_data.a_ops = &efs_aops;
			break;
		case S_IFLNK:
			inode->i_op = &page_symlink_inode_operations;
			inode->i_data.a_ops = &efs_symlink_aops;
			break;
		case S_IFCHR:
		case S_IFBLK:
		case S_IFIFO:
			init_special_inode(inode, inode->i_mode, device);
			break;
		default:
			printk(KERN_WARNING "EFS: unsupported inode mode %o\n", inode->i_mode);
			goto read_inode_error;
			break;
	}

	unlock_new_inode(inode);
	return inode;
        
read_inode_error:
	printk(KERN_WARNING "EFS: failed to read inode %lu\n", inode->i_ino);
	iget_failed(inode);
	return ERR_PTR(-EIO);
}

static inline efs_block_t
efs_extent_check(efs_extent *ptr, efs_block_t block, struct efs_sb_info *sb) {
	efs_block_t start;
	efs_block_t length;
	efs_block_t offset;

	/*
	 * given an extent and a logical block within a file,
	 * can this block be found within this extent ?
	 */
	start  = ptr->cooked.ex_bn;
	length = ptr->cooked.ex_length;
	offset = ptr->cooked.ex_offset;

	if ((block >= offset) && (block < offset+length)) {
		return(sb->fs_start + start + block - offset);
	} else {
		return 0;
	}
}

efs_block_t efs_map_block(struct inode *inode, efs_block_t block) {
	struct efs_sb_info    *sb = SUPER_INFO(inode->i_sb);
	struct efs_inode_info *in = INODE_INFO(inode);
	struct buffer_head    *bh = NULL;

	int cur, last, first = 1;
	int ibase, ioffset, dirext, direxts, indext, indexts;
	efs_block_t iblock, result = 0, lastblock = 0;
	efs_extent ext, *exts;

	last = in->lastextent;

	if (in->numextents <= EFS_DIRECTEXTENTS) {
		/* first check the last extent we returned */
		if ((result = efs_extent_check(&in->extents[last], block, sb)))
			return result;
    
		/* if we only have one extent then nothing can be found */
		if (in->numextents == 1) {
			printk(KERN_ERR "EFS: map_block() failed to map (1 extent)\n");
			return 0;
		}

		direxts = in->numextents;

		/*
		 * check the stored extents in the inode
		 * start with next extent and check forwards
		 */
		for(dirext = 1; dirext < direxts; dirext++) {
			cur = (last + dirext) % in->numextents;
			if ((result = efs_extent_check(&in->extents[cur], block, sb))) {
				in->lastextent = cur;
				return result;
			}
		}

		printk(KERN_ERR "EFS: map_block() failed to map block %u (dir)\n", block);
		return 0;
	}

#ifdef DEBUG
	printk(KERN_DEBUG "EFS: map_block(): indirect search for logical block %u\n", block);
#endif
	direxts = in->extents[0].cooked.ex_offset;
	indexts = in->numextents;

	for(indext = 0; indext < indexts; indext++) {
		cur = (last + indext) % indexts;

		/*
		 * work out which direct extent contains `cur'.
		 *
		 * also compute ibase: i.e. the number of the first
		 * indirect extent contained within direct extent `cur'.
		 *
		 */
		ibase = 0;
		for(dirext = 0; cur < ibase && dirext < direxts; dirext++) {
			ibase += in->extents[dirext].cooked.ex_length *
				(EFS_BLOCKSIZE / sizeof(efs_extent));
		}

		if (dirext == direxts) {
			/* should never happen */
			printk(KERN_ERR "EFS: couldn't find direct extent for indirect extent %d (block %u)\n", cur, block);
			if (bh) brelse(bh);
			return 0;
		}
		
		/* work out block number and offset of this indirect extent */
		iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn +
			(cur - ibase) /
			(EFS_BLOCKSIZE / sizeof(efs_extent));
		ioffset = (cur - ibase) %
			(EFS_BLOCKSIZE / sizeof(efs_extent));

		if (first || lastblock != iblock) {
			if (bh) brelse(bh);

			bh = sb_bread(inode->i_sb, iblock);
			if (!bh) {
				printk(KERN_ERR "EFS: bread() failed at block %d\n", iblock);
				return 0;
			}
#ifdef DEBUG
			printk(KERN_DEBUG "EFS: map_block(): read indirect extent block %d\n", iblock);
#endif
			first = 0;
			lastblock = iblock;
		}

		exts = (efs_extent *) bh->b_data;

		extent_copy(&(exts[ioffset]), &ext);

		if (ext.cooked.ex_magic != 0) {
			printk(KERN_ERR "EFS: extent %d has bad magic number in block %d\n", cur, iblock);
			if (bh) brelse(bh);
			return 0;
		}

		if ((result = efs_extent_check(&ext, block, sb))) {
			if (bh) brelse(bh);
			in->lastextent = cur;
			return result;
		}
	}
	if (bh) brelse(bh);
	printk(KERN_ERR "EFS: map_block() failed to map block %u (indir)\n", block);
	return 0;
}  

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* inode.c
	3	*
	4	* Copyright (c) 1999 Al Smith
	5	*
	6	* Portions derived from work (c) 1995,1996 Christian Vogelgsang,
	7	* and from work (c) 1998 Mike Shaver.
	8	*/
	9
1da177e4 LT	10	#include <linux/buffer_head.h>
	11	#include <linux/module.h>
	12	#include <linux/fs.h>
45254b4f CH	13	#include "efs.h"
45254b4f CH	14	#include <linux/efs_fs_sb.h>
1da177e4 LT	15
	16	static int efs_readpage(struct file file, struct page page)
	17	{
	18	return block_read_full_page(page,efs_get_block);
	19	}
	20	static sector_t _efs_bmap(struct address_space *mapping, sector_t block)
	21	{
	22	return generic_block_bmap(mapping,block,efs_get_block);
	23	}
f5e54d6e	24	static const struct address_space_operations efs_aops = {
1da177e4 LT	25	.readpage = efs_readpage,
	26	.sync_page = block_sync_page,
	27	.bmap = _efs_bmap
	28	};
	29
	30	static inline void extent_copy(efs_extent src, efs_extent dst) {
	31	/*
	32	* this is slightly evil. it doesn't just copy
	33	* efs_extent from src to dst, it also mangles
	34	* the bits so that dst ends up in cpu byte-order.
	35	*/
	36
	37	dst->cooked.ex_magic = (unsigned int) src->raw[0];
	38	dst->cooked.ex_bn = ((unsigned int) src->raw[1] << 16) \|
	39	((unsigned int) src->raw[2] << 8) \|
	40	((unsigned int) src->raw[3] << 0);
	41	dst->cooked.ex_length = (unsigned int) src->raw[4];
	42	dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) \|
	43	((unsigned int) src->raw[6] << 8) \|
	44	((unsigned int) src->raw[7] << 0);
	45	return;
	46	}
	47
298384cd	48	struct inode efs_iget(struct super_block super, unsigned long ino)
1da177e4 LT	49	{
	50	int i, inode_index;
	51	dev_t device;
	52	u32 rdev;
	53	struct buffer_head *bh;
298384cd DH	54	struct efs_sb_info *sb = SUPER_INFO(super);
298384cd DH	55	struct efs_inode_info *in;
1da177e4 LT	56	efs_block_t block, offset;
1da177e4 LT	57	struct efs_dinode *efs_inode;
298384cd DH	58	struct inode *inode;
	59
	60	inode = iget_locked(super, ino);
	61	if (IS_ERR(inode))
	62	return ERR_PTR(-ENOMEM);
	63	if (!(inode->i_state & I_NEW))
	64	return inode;
	65
	66	in = INODE_INFO(inode);
	67
1da177e4 LT	68	/*
	69	** EFS layout:
	70	**
	71	** \| cylinder group \| cylinder group \| cylinder group ..etc
	72	** \|inodes\|data \|inodes\|data \|inodes\|data ..etc
	73	**
	74	** work out the inode block index, (considering initially that the
	75	** inodes are stored as consecutive blocks). then work out the block
	76	** number of that inode given the above layout, and finally the
	77	** offset of the inode within that block.
	78	*/
	79
	80	inode_index = inode->i_ino /
	81	(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
	82
	83	block = sb->fs_start + sb->first_block +
	84	(sb->group_size * (inode_index / sb->inode_blocks)) +
	85	(inode_index % sb->inode_blocks);
	86
	87	offset = (inode->i_ino %
	88	(EFS_BLOCKSIZE / sizeof(struct efs_dinode))) *
	89	sizeof(struct efs_dinode);
	90
	91	bh = sb_bread(inode->i_sb, block);
	92	if (!bh) {
	93	printk(KERN_WARNING "EFS: bread() failed at block %d\n", block);
	94	goto read_inode_error;
	95	}
	96
	97	efs_inode = (struct efs_dinode *) (bh->b_data + offset);
	98
	99	inode->i_mode = be16_to_cpu(efs_inode->di_mode);
	100	inode->i_nlink = be16_to_cpu(efs_inode->di_nlink);
	101	inode->i_uid = (uid_t)be16_to_cpu(efs_inode->di_uid);
	102	inode->i_gid = (gid_t)be16_to_cpu(efs_inode->di_gid);
	103	inode->i_size = be32_to_cpu(efs_inode->di_size);
	104	inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime);
	105	inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime);
	106	inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime);
	107	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
	108
	109	/* this is the number of blocks in the file */
	110	if (inode->i_size == 0) {
	111	inode->i_blocks = 0;
	112	} else {
	113	inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1;
	114	}
	115
	116	rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev);
	117	if (rdev == 0xffff) {
	118	rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev);
	119	if (sysv_major(rdev) > 0xfff)
	120	device = 0;
	121	else
	122	device = MKDEV(sysv_major(rdev), sysv_minor(rdev));
	123	} else
	124	device = old_decode_dev(rdev);
	125
	126	/* get the number of extents for this object */
	127	in->numextents = be16_to_cpu(efs_inode->di_numextents);
	128	in->lastextent = 0;
	129
	130	/* copy the extents contained within the inode to memory */
	131	for(i = 0; i < EFS_DIRECTEXTENTS; i++) {
132	extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i]));
133	if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) {
134	printk(KERN_WARNING "EFS: extent %d has bad magic number in inode %lu\n", i, inode->i_ino);
135	brelse(bh);
136	goto read_inode_error;
137	}
138	}
139
140	brelse(bh);
141
142	#ifdef DEBUG
865965a6	143	printk(KERN_DEBUG "EFS: efs_iget(): inode %lu, extents %d, mode %o\n",
1da177e4 LT	144	inode->i_ino, in->numextents, inode->i_mode);
	145	#endif
	146
	147	switch (inode->i_mode & S_IFMT) {
	148	case S_IFDIR:
	149	inode->i_op = &efs_dir_inode_operations;
	150	inode->i_fop = &efs_dir_operations;
	151	break;
	152	case S_IFREG:
	153	inode->i_fop = &generic_ro_fops;
	154	inode->i_data.a_ops = &efs_aops;
	155	break;
	156	case S_IFLNK:
	157	inode->i_op = &page_symlink_inode_operations;
	158	inode->i_data.a_ops = &efs_symlink_aops;
	159	break;
	160	case S_IFCHR:
	161	case S_IFBLK:
	162	case S_IFIFO:
	163	init_special_inode(inode, inode->i_mode, device);
	164	break;
	165	default:
	166	printk(KERN_WARNING "EFS: unsupported inode mode %o\n", inode->i_mode);
	167	goto read_inode_error;
	168	break;
	169	}
	170
298384cd DH	171	unlock_new_inode(inode);
298384cd DH	172	return inode;
1da177e4 LT	173
	174	read_inode_error:
	175	printk(KERN_WARNING "EFS: failed to read inode %lu\n", inode->i_ino);
298384cd DH	176	iget_failed(inode);
298384cd DH	177	return ERR_PTR(-EIO);
1da177e4 LT	178	}
	179
	180	static inline efs_block_t
	181	efs_extent_check(efs_extent ptr, efs_block_t block, struct efs_sb_info sb) {
	182	efs_block_t start;
	183	efs_block_t length;
	184	efs_block_t offset;
	185
	186	/*
	187	* given an extent and a logical block within a file,
	188	* can this block be found within this extent ?
	189	*/
	190	start = ptr->cooked.ex_bn;
	191	length = ptr->cooked.ex_length;
	192	offset = ptr->cooked.ex_offset;
	193
	194	if ((block >= offset) && (block < offset+length)) {
	195	return(sb->fs_start + start + block - offset);
	196	} else {
	197	return 0;
	198	}
	199	}
	200
	201	efs_block_t efs_map_block(struct inode *inode, efs_block_t block) {
	202	struct efs_sb_info *sb = SUPER_INFO(inode->i_sb);
	203	struct efs_inode_info *in = INODE_INFO(inode);
	204	struct buffer_head *bh = NULL;
	205
	206	int cur, last, first = 1;
	207	int ibase, ioffset, dirext, direxts, indext, indexts;
	208	efs_block_t iblock, result = 0, lastblock = 0;
	209	efs_extent ext, *exts;
	210
	211	last = in->lastextent;
	212
	213	if (in->numextents <= EFS_DIRECTEXTENTS) {
	214	/* first check the last extent we returned */
	215	if ((result = efs_extent_check(&in->extents[last], block, sb)))
	216	return result;
	217
	218	/* if we only have one extent then nothing can be found */
	219	if (in->numextents == 1) {
	220	printk(KERN_ERR "EFS: map_block() failed to map (1 extent)\n");
	221	return 0;
	222	}
	223
	224	direxts = in->numextents;
	225
	226	/*
	227	* check the stored extents in the inode
	228	* start with next extent and check forwards
	229	*/
	230	for(dirext = 1; dirext < direxts; dirext++) {
	231	cur = (last + dirext) % in->numextents;
	232	if ((result = efs_extent_check(&in->extents[cur], block, sb))) {
	233	in->lastextent = cur;
	234	return result;
	235	}
	236	}
	237
	238	printk(KERN_ERR "EFS: map_block() failed to map block %u (dir)\n", block);
	239	return 0;
	240	}
	241
242	#ifdef DEBUG
243	printk(KERN_DEBUG "EFS: map_block(): indirect search for logical block %u\n", block);
244	#endif
245	direxts = in->extents[0].cooked.ex_offset;
246	indexts = in->numextents;
247
248	for(indext = 0; indext < indexts; indext++) {
249	cur = (last + indext) % indexts;
250
251	/*
252	* work out which direct extent contains `cur'.
253	*
254	* also compute ibase: i.e. the number of the first
255	* indirect extent contained within direct extent `cur'.
256	*
257	*/
258	ibase = 0;
259	for(dirext = 0; cur < ibase && dirext < direxts; dirext++) {
260	ibase += in->extents[dirext].cooked.ex_length *
261	(EFS_BLOCKSIZE / sizeof(efs_extent));
262	}
263
264	if (dirext == direxts) {
265	/* should never happen */
266	printk(KERN_ERR "EFS: couldn't find direct extent for indirect extent %d (block %u)\n", cur, block);
267	if (bh) brelse(bh);
268	return 0;
269	}
270
271	/* work out block number and offset of this indirect extent */
272	iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn +
273	(cur - ibase) /
274	(EFS_BLOCKSIZE / sizeof(efs_extent));
275	ioffset = (cur - ibase) %
276	(EFS_BLOCKSIZE / sizeof(efs_extent));
277
278	if (first \|\| lastblock != iblock) {
279	if (bh) brelse(bh);
280
281	bh = sb_bread(inode->i_sb, iblock);
282	if (!bh) {
283	printk(KERN_ERR "EFS: bread() failed at block %d\n", iblock);
284	return 0;
285	}
286	#ifdef DEBUG
287	printk(KERN_DEBUG "EFS: map_block(): read indirect extent block %d\n", iblock);
288	#endif
289	first = 0;
290	lastblock = iblock;
291	}
292
293	exts = (efs_extent *) bh->b_data;
294
295	extent_copy(&(exts[ioffset]), &ext);
296
297	if (ext.cooked.ex_magic != 0) {
298	printk(KERN_ERR "EFS: extent %d has bad magic number in block %d\n", cur, iblock);
299	if (bh) brelse(bh);
300	return 0;
301	}
302
303	if ((result = efs_extent_check(&ext, block, sb))) {
304	if (bh) brelse(bh);
305	in->lastextent = cur;
306	return result;
307	}
308	}
309	if (bh) brelse(bh);
310	printk(KERN_ERR "EFS: map_block() failed to map block %u (indir)\n", block);
311	return 0;
312	}
313
314	MODULE_LICENSE("GPL");