[deliverable/linux.git] / fs / freevxfs / vxfs_lookup.c

/*
 * Copyright (c) 2000-2001 Christoph Hellwig.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL").
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Veritas filesystem driver - lookup and other directory related code.
 */
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>

#include "vxfs.h"
#include "vxfs_dir.h"
#include "vxfs_inode.h"
#include "vxfs_extern.h"

/*
 * Number of VxFS blocks per page.
 */
#define VXFS_BLOCK_PER_PAGE(sbp)  ((PAGE_CACHE_SIZE / (sbp)->s_blocksize))


static struct dentry *	vxfs_lookup(struct inode *, struct dentry *, unsigned int);
static int		vxfs_readdir(struct file *, struct dir_context *);

const struct inode_operations vxfs_dir_inode_ops = {
	.lookup =		vxfs_lookup,
};

const struct file_operations vxfs_dir_operations = {
	.llseek =		generic_file_llseek,
	.read =			generic_read_dir,
	.iterate =		vxfs_readdir,
};

 
static inline u_long
dir_pages(struct inode *inode)
{
	return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
}
 
static inline u_long
dir_blocks(struct inode *ip)
{
	u_long			bsize = ip->i_sb->s_blocksize;
	return (ip->i_size + bsize - 1) & ~(bsize - 1);
}

/*
 * NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure.
 *
 * len <= VXFS_NAMELEN and de != NULL are guaranteed by caller.
 */
static inline int
vxfs_match(int len, const char * const name, struct vxfs_direct *de)
{
	if (len != de->d_namelen)
		return 0;
	if (!de->d_ino)
		return 0;
	return !memcmp(name, de->d_name, len);
}

static inline struct vxfs_direct *
vxfs_next_entry(struct vxfs_direct *de)
{
	return ((struct vxfs_direct *)((char*)de + de->d_reclen));
}

/**
 * vxfs_find_entry - find a mathing directory entry for a dentry
 * @ip:		directory inode
 * @dp:		dentry for which we want to find a direct
 * @ppp:	gets filled with the page the return value sits in
 *
 * Description:
 *   vxfs_find_entry finds a &struct vxfs_direct for the VFS directory
 *   cache entry @dp.  @ppp will be filled with the page the return
 *   value resides in.
 *
 * Returns:
 *   The wanted direct on success, else a NULL pointer.
 */
static struct vxfs_direct *
vxfs_find_entry(struct inode *ip, struct dentry *dp, struct page **ppp)
{
	u_long				npages, page, nblocks, pblocks, block;
	u_long				bsize = ip->i_sb->s_blocksize;
	const char			*name = dp->d_name.name;
	int				namelen = dp->d_name.len;

	npages = dir_pages(ip);
	nblocks = dir_blocks(ip);
	pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb);
	
	for (page = 0; page < npages; page++) {
		caddr_t			kaddr;
		struct page		*pp;

		pp = vxfs_get_page(ip->i_mapping, page);
		if (IS_ERR(pp))
			continue;
		kaddr = (caddr_t)page_address(pp);

		for (block = 0; block <= nblocks && block <= pblocks; block++) {
			caddr_t			baddr, limit;
			struct vxfs_dirblk	*dbp;
			struct vxfs_direct	*de;

			baddr = kaddr + (block * bsize);
			limit = baddr + bsize - VXFS_DIRLEN(1);
			
			dbp = (struct vxfs_dirblk *)baddr;
			de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp));

			for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
				if (!de->d_reclen)
					break;
				if (!de->d_ino)
					continue;
				if (vxfs_match(namelen, name, de)) {
					*ppp = pp;
					return (de);
				}
			}
		}
		vxfs_put_page(pp);
	}

	return NULL;
}

/**
 * vxfs_inode_by_name - find inode number for dentry
 * @dip:	directory to search in
 * @dp:		dentry we search for
 *
 * Description:
 *   vxfs_inode_by_name finds out the inode number of
 *   the path component described by @dp in @dip.
 *
 * Returns:
 *   The wanted inode number on success, else Zero.
 */
static ino_t
vxfs_inode_by_name(struct inode *dip, struct dentry *dp)
{
	struct vxfs_direct		*de;
	struct page			*pp;
	ino_t				ino = 0;

	de = vxfs_find_entry(dip, dp, &pp);
	if (de) {
		ino = de->d_ino;
		kunmap(pp);
		page_cache_release(pp);
	}
	
	return (ino);
}

/**
 * vxfs_lookup - lookup pathname component
 * @dip:	dir in which we lookup
 * @dp:		dentry we lookup
 * @flags:	lookup flags
 *
 * Description:
 *   vxfs_lookup tries to lookup the pathname component described
 *   by @dp in @dip.
 *
 * Returns:
 *   A NULL-pointer on success, else an negative error code encoded
 *   in the return pointer.
 */
static struct dentry *
vxfs_lookup(struct inode *dip, struct dentry *dp, unsigned int flags)
{
	struct inode		*ip = NULL;
	ino_t			ino;
			 
	if (dp->d_name.len > VXFS_NAMELEN)
		return ERR_PTR(-ENAMETOOLONG);
				 
	ino = vxfs_inode_by_name(dip, dp);
	if (ino) {
		ip = vxfs_iget(dip->i_sb, ino);
		if (IS_ERR(ip))
			return ERR_CAST(ip);
	}
	d_add(dp, ip);
	return NULL;
}

/**
 * vxfs_readdir - read a directory
 * @fp:		the directory to read
 * @retp:	return buffer
 * @filler:	filldir callback
 *
 * Description:
 *   vxfs_readdir fills @retp with directory entries from @fp
 *   using the VFS supplied callback @filler.
 *
 * Returns:
 *   Zero.
 */
static int
vxfs_readdir(struct file *fp, struct dir_context *ctx)
{
	struct inode		*ip = file_inode(fp);
	struct super_block	*sbp = ip->i_sb;
	u_long			bsize = sbp->s_blocksize;
	u_long			page, npages, block, pblocks, nblocks, offset;
	loff_t			pos;

	if (ctx->pos == 0) {
		if (!dir_emit_dot(fp, ctx))
			return 0;
		ctx->pos = 1;
	}
	if (ctx->pos == 1) {
		if (!dir_emit(ctx, "..", 2, VXFS_INO(ip)->vii_dotdot, DT_DIR))
			return 0;
		ctx->pos = 2;
	}
	pos = ctx->pos - 2;
	
	if (pos > VXFS_DIRROUND(ip->i_size))
		return 0;

	npages = dir_pages(ip);
	nblocks = dir_blocks(ip);
	pblocks = VXFS_BLOCK_PER_PAGE(sbp);

	page = pos >> PAGE_CACHE_SHIFT;
	offset = pos & ~PAGE_CACHE_MASK;
	block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks;

	for (; page < npages; page++, block = 0) {
		char			*kaddr;
		struct page		*pp;

		pp = vxfs_get_page(ip->i_mapping, page);
		if (IS_ERR(pp))
			continue;
		kaddr = (char *)page_address(pp);

		for (; block <= nblocks && block <= pblocks; block++) {
			char			*baddr, *limit;
			struct vxfs_dirblk	*dbp;
			struct vxfs_direct	*de;

			baddr = kaddr + (block * bsize);
			limit = baddr + bsize - VXFS_DIRLEN(1);
	
			dbp = (struct vxfs_dirblk *)baddr;
			de = (struct vxfs_direct *)
				(offset ?
				 (kaddr + offset) :
				 (baddr + VXFS_DIRBLKOV(dbp)));

			for (; (char *)de <= limit; de = vxfs_next_entry(de)) {
				if (!de->d_reclen)
					break;
				if (!de->d_ino)
					continue;

				offset = (char *)de - kaddr;
				ctx->pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
				if (!dir_emit(ctx, de->d_name, de->d_namelen,
					de->d_ino, DT_UNKNOWN)) {
					vxfs_put_page(pp);
					return 0;
				}
			}
			offset = 0;
		}
		vxfs_put_page(pp);
		offset = 0;
	}
	ctx->pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Copyright (c) 2000-2001 Christoph Hellwig.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions, and the following disclaimer,
	10	* without modification.
	11	* 2. The name of the author may not be used to endorse or promote products
	12	* derived from this software without specific prior written permission.
	13	*
	14	* Alternatively, this software may be distributed under the terms of the
	15	* GNU General Public License ("GPL").
	16	*
	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	18	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	19	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	20	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
	21	* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	22	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	23	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	24	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	25	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	27	* SUCH DAMAGE.
	28	*/
	29
	30	/*
	31	* Veritas filesystem driver - lookup and other directory related code.
	32	*/
	33	#include <linux/fs.h>
	34	#include <linux/time.h>
	35	#include <linux/mm.h>
	36	#include <linux/highmem.h>
	37	#include <linux/kernel.h>
	38	#include <linux/pagemap.h>
1da177e4 LT	39
	40	#include "vxfs.h"
	41	#include "vxfs_dir.h"
	42	#include "vxfs_inode.h"
	43	#include "vxfs_extern.h"
	44
	45	/*
	46	* Number of VxFS blocks per page.
	47	*/
	48	#define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_CACHE_SIZE / (sbp)->s_blocksize))
	49
	50
00cd8dd3	51	static struct dentry * vxfs_lookup(struct inode , struct dentry , unsigned int);
9b5d5a17	52	static int vxfs_readdir(struct file , struct dir_context );
1da177e4	53
754661f1	54	const struct inode_operations vxfs_dir_inode_ops = {
1da177e4 LT	55	.lookup = vxfs_lookup,
	56	};
	57
4b6f5d20	58	const struct file_operations vxfs_dir_operations = {
ca572727 B	59	.llseek = generic_file_llseek,
ca572727 B	60	.read = generic_read_dir,
9b5d5a17	61	.iterate = vxfs_readdir,
1da177e4 LT	62	};
	63
	64
8cb681b9	65	static inline u_long
1da177e4 LT	66	dir_pages(struct inode *inode)
	67	{
	68	return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
	69	}
	70
8cb681b9	71	static inline u_long
1da177e4 LT	72	dir_blocks(struct inode *ip)
	73	{
	74	u_long bsize = ip->i_sb->s_blocksize;
	75	return (ip->i_size + bsize - 1) & ~(bsize - 1);
	76	}
	77
	78	/*
	79	* NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure.
	80	*
	81	* len <= VXFS_NAMELEN and de != NULL are guaranteed by caller.
	82	*/
8cb681b9	83	static inline int
1da177e4 LT	84	vxfs_match(int len, const char * const name, struct vxfs_direct *de)
	85	{
	86	if (len != de->d_namelen)
	87	return 0;
	88	if (!de->d_ino)
	89	return 0;
	90	return !memcmp(name, de->d_name, len);
	91	}
	92
8cb681b9	93	static inline struct vxfs_direct *
1da177e4 LT	94	vxfs_next_entry(struct vxfs_direct *de)
	95	{
	96	return ((struct vxfs_direct )((char)de + de->d_reclen));
	97	}
	98
	99	/**
	100	* vxfs_find_entry - find a mathing directory entry for a dentry
	101	* @ip: directory inode
	102	* @dp: dentry for which we want to find a direct
	103	* @ppp: gets filled with the page the return value sits in
	104	*
	105	* Description:
	106	* vxfs_find_entry finds a &struct vxfs_direct for the VFS directory
	107	* cache entry @dp. @ppp will be filled with the page the return
	108	* value resides in.
	109	*
	110	* Returns:
	111	* The wanted direct on success, else a NULL pointer.
	112	*/
	113	static struct vxfs_direct *
	114	vxfs_find_entry(struct inode ip, struct dentry dp, struct page **ppp)
	115	{
	116	u_long npages, page, nblocks, pblocks, block;
	117	u_long bsize = ip->i_sb->s_blocksize;
	118	const char *name = dp->d_name.name;
	119	int namelen = dp->d_name.len;
	120
	121	npages = dir_pages(ip);
	122	nblocks = dir_blocks(ip);
	123	pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb);
	124
	125	for (page = 0; page < npages; page++) {
	126	caddr_t kaddr;
	127	struct page *pp;
	128
	129	pp = vxfs_get_page(ip->i_mapping, page);
	130	if (IS_ERR(pp))
	131	continue;
	132	kaddr = (caddr_t)page_address(pp);
	133
	134	for (block = 0; block <= nblocks && block <= pblocks; block++) {
	135	caddr_t baddr, limit;
	136	struct vxfs_dirblk *dbp;
	137	struct vxfs_direct *de;
	138
	139	baddr = kaddr + (block * bsize);
	140	limit = baddr + bsize - VXFS_DIRLEN(1);
	141
	142	dbp = (struct vxfs_dirblk *)baddr;
	143	de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp));
	144
	145	for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
	146	if (!de->d_reclen)
	147	break;
	148	if (!de->d_ino)
	149	continue;
	150	if (vxfs_match(namelen, name, de)) {
	151	*ppp = pp;
	152	return (de);
	153	}
	154	}
	155	}
	156	vxfs_put_page(pp);
	157	}
158
159	return NULL;
160	}
161
162	/**
163	* vxfs_inode_by_name - find inode number for dentry
164	* @dip: directory to search in
25985edc	165	* @dp: dentry we search for
1da177e4 LT	166	*
	167	* Description:
	168	* vxfs_inode_by_name finds out the inode number of
	169	* the path component described by @dp in @dip.
	170	*
	171	* Returns:
	172	* The wanted inode number on success, else Zero.
	173	*/
	174	static ino_t
	175	vxfs_inode_by_name(struct inode dip, struct dentry dp)
	176	{
	177	struct vxfs_direct *de;
	178	struct page *pp;
	179	ino_t ino = 0;
	180
	181	de = vxfs_find_entry(dip, dp, &pp);
	182	if (de) {
	183	ino = de->d_ino;
	184	kunmap(pp);
	185	page_cache_release(pp);
	186	}
	187
	188	return (ino);
	189	}
	190
	191	/**
	192	* vxfs_lookup - lookup pathname component
	193	* @dip: dir in which we lookup
	194	* @dp: dentry we lookup
ddae82d8	195	* @flags: lookup flags
1da177e4 LT	196	*
	197	* Description:
	198	* vxfs_lookup tries to lookup the pathname component described
	199	* by @dp in @dip.
	200	*
	201	* Returns:
	202	* A NULL-pointer on success, else an negative error code encoded
	203	* in the return pointer.
	204	*/
	205	static struct dentry *
00cd8dd3	206	vxfs_lookup(struct inode dip, struct dentry dp, unsigned int flags)
1da177e4 LT	207	{
	208	struct inode *ip = NULL;
	209	ino_t ino;
	210
	211	if (dp->d_name.len > VXFS_NAMELEN)
	212	return ERR_PTR(-ENAMETOOLONG);
	213
1da177e4 LT	214	ino = vxfs_inode_by_name(dip, dp);
1da177e4 LT	215	if (ino) {
d0b07948	216	ip = vxfs_iget(dip->i_sb, ino);
6d7bccc2	217	if (IS_ERR(ip))
d0b07948	218	return ERR_CAST(ip);
1da177e4	219	}
1da177e4 LT	220	d_add(dp, ip);
	221	return NULL;
	222	}
	223
	224	/**
	225	* vxfs_readdir - read a directory
	226	* @fp: the directory to read
	227	* @retp: return buffer
	228	* @filler: filldir callback
	229	*
	230	* Description:
	231	* vxfs_readdir fills @retp with directory entries from @fp
	232	* using the VFS supplied callback @filler.
	233	*
	234	* Returns:
	235	* Zero.
	236	*/
	237	static int
9b5d5a17	238	vxfs_readdir(struct file fp, struct dir_context ctx)
1da177e4	239	{
496ad9aa	240	struct inode *ip = file_inode(fp);
1da177e4 LT	241	struct super_block *sbp = ip->i_sb;
	242	u_long bsize = sbp->s_blocksize;
	243	u_long page, npages, block, pblocks, nblocks, offset;
	244	loff_t pos;
	245
9b5d5a17 AV	246	if (ctx->pos == 0) {
	247	if (!dir_emit_dot(fp, ctx))
	248	return 0;
	249	ctx->pos = 1;
1da177e4	250	}
9b5d5a17 AV	251	if (ctx->pos == 1) {
	252	if (!dir_emit(ctx, "..", 2, VXFS_INO(ip)->vii_dotdot, DT_DIR))
	253	return 0;
	254	ctx->pos = 2;
	255	}
	256	pos = ctx->pos - 2;
1da177e4	257
6d7bccc2	258	if (pos > VXFS_DIRROUND(ip->i_size))
1da177e4	259	return 0;
1da177e4 LT	260
	261	npages = dir_pages(ip);
	262	nblocks = dir_blocks(ip);
	263	pblocks = VXFS_BLOCK_PER_PAGE(sbp);
	264
	265	page = pos >> PAGE_CACHE_SHIFT;
	266	offset = pos & ~PAGE_CACHE_MASK;
	267	block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks;
	268
	269	for (; page < npages; page++, block = 0) {
9b5d5a17	270	char *kaddr;
1da177e4 LT	271	struct page *pp;
	272
	273	pp = vxfs_get_page(ip->i_mapping, page);
	274	if (IS_ERR(pp))
	275	continue;
9b5d5a17	276	kaddr = (char *)page_address(pp);
1da177e4 LT	277
1da177e4 LT	278	for (; block <= nblocks && block <= pblocks; block++) {
9b5d5a17	279	char baddr, limit;
1da177e4 LT	280	struct vxfs_dirblk *dbp;
	281	struct vxfs_direct *de;
	282
	283	baddr = kaddr + (block * bsize);
	284	limit = baddr + bsize - VXFS_DIRLEN(1);
	285
	286	dbp = (struct vxfs_dirblk *)baddr;
	287	de = (struct vxfs_direct *)
	288	(offset ?
	289	(kaddr + offset) :
	290	(baddr + VXFS_DIRBLKOV(dbp)));
	291
9b5d5a17	292	for (; (char *)de <= limit; de = vxfs_next_entry(de)) {
1da177e4 LT	293	if (!de->d_reclen)
	294	break;
	295	if (!de->d_ino)
	296	continue;
	297
9b5d5a17 AV	298	offset = (char *)de - kaddr;
	299	ctx->pos = ((page << PAGE_CACHE_SHIFT) \| offset) + 2;
	300	if (!dir_emit(ctx, de->d_name, de->d_namelen,
	301	de->d_ino, DT_UNKNOWN)) {
1da177e4	302	vxfs_put_page(pp);
9b5d5a17	303	return 0;
1da177e4 LT	304	}
	305	}
	306	offset = 0;
	307	}
	308	vxfs_put_page(pp);
	309	offset = 0;
	310	}
9b5d5a17	311	ctx->pos = ((page << PAGE_CACHE_SHIFT) \| offset) + 2;
1da177e4 LT	312	return 0;
1da177e4 LT	313	}