[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 <linux/smp_lock.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 *, struct nameidata *);
static int		vxfs_readdir(struct file *, void *, filldir_t);

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

const struct file_operations vxfs_dir_operations = {
	.readdir =		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 seach 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
 * @nd:		lookup nameidata
 *
 * 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, struct nameidata *nd)
{
	struct inode		*ip = NULL;
	ino_t			ino;
			 
	if (dp->d_name.len > VXFS_NAMELEN)
		return ERR_PTR(-ENAMETOOLONG);
				 
	lock_kernel();
	ino = vxfs_inode_by_name(dip, dp);
	if (ino) {
		ip = iget(dip->i_sb, ino);
		if (!ip) {
			unlock_kernel();
			return ERR_PTR(-EACCES);
		}
	}
	unlock_kernel();
	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, void *retp, filldir_t filler)
{
	struct inode		*ip = fp->f_dentry->d_inode;
	struct super_block	*sbp = ip->i_sb;
	u_long			bsize = sbp->s_blocksize;
	u_long			page, npages, block, pblocks, nblocks, offset;
	loff_t			pos;

	switch ((long)fp->f_pos) {
	case 0:
		if (filler(retp, ".", 1, fp->f_pos, ip->i_ino, DT_DIR) < 0)
			goto out;
		fp->f_pos++;
		/* fallthrough */
	case 1:
		if (filler(retp, "..", 2, fp->f_pos, VXFS_INO(ip)->vii_dotdot, DT_DIR) < 0)
			goto out;
		fp->f_pos++;
		/* fallthrough */
	}

	pos = fp->f_pos - 2;
	
	if (pos > VXFS_DIRROUND(ip->i_size)) {
		unlock_kernel();
		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) {
		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 <= 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 *)
				(offset ?
				 (kaddr + offset) :
				 (baddr + VXFS_DIRBLKOV(dbp)));

			for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
				int	over;

				if (!de->d_reclen)
					break;
				if (!de->d_ino)
					continue;

				offset = (caddr_t)de - kaddr;
				over = filler(retp, de->d_name, de->d_namelen,
					((page << PAGE_CACHE_SHIFT) | offset) + 2,
					de->d_ino, DT_UNKNOWN);
				if (over) {
					vxfs_put_page(pp);
					goto done;
				}
			}
			offset = 0;
		}
		vxfs_put_page(pp);
		offset = 0;
	}

done:
	fp->f_pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
out:
	unlock_kernel();
	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>
	39	#include <linux/smp_lock.h>
	40
	41	#include "vxfs.h"
	42	#include "vxfs_dir.h"
	43	#include "vxfs_inode.h"
	44	#include "vxfs_extern.h"
	45
	46	/*
	47	* Number of VxFS blocks per page.
	48	*/
	49	#define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_CACHE_SIZE / (sbp)->s_blocksize))
	50
	51
	52	static struct dentry * vxfs_lookup(struct inode , struct dentry , struct nameidata *);
	53	static int vxfs_readdir(struct file , void , filldir_t);
	54
	55	struct inode_operations vxfs_dir_inode_ops = {
	56	.lookup = vxfs_lookup,
	57	};
	58
4b6f5d20	59	const struct file_operations vxfs_dir_operations = {
1da177e4 LT	60	.readdir = vxfs_readdir,
	61	};
	62
	63
8cb681b9	64	static inline u_long
1da177e4 LT	65	dir_pages(struct inode *inode)
	66	{
	67	return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
	68	}
	69
8cb681b9	70	static inline u_long
1da177e4 LT	71	dir_blocks(struct inode *ip)
	72	{
	73	u_long bsize = ip->i_sb->s_blocksize;
	74	return (ip->i_size + bsize - 1) & ~(bsize - 1);
	75	}
	76
	77	/*
	78	* NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure.
	79	*
	80	* len <= VXFS_NAMELEN and de != NULL are guaranteed by caller.
	81	*/
8cb681b9	82	static inline int
1da177e4 LT	83	vxfs_match(int len, const char * const name, struct vxfs_direct *de)
	84	{
	85	if (len != de->d_namelen)
	86	return 0;
	87	if (!de->d_ino)
	88	return 0;
	89	return !memcmp(name, de->d_name, len);
	90	}
	91
8cb681b9	92	static inline struct vxfs_direct *
1da177e4 LT	93	vxfs_next_entry(struct vxfs_direct *de)
	94	{
	95	return ((struct vxfs_direct )((char)de + de->d_reclen));
	96	}
	97
	98	/**
	99	* vxfs_find_entry - find a mathing directory entry for a dentry
	100	* @ip: directory inode
	101	* @dp: dentry for which we want to find a direct
	102	* @ppp: gets filled with the page the return value sits in
	103	*
	104	* Description:
	105	* vxfs_find_entry finds a &struct vxfs_direct for the VFS directory
	106	* cache entry @dp. @ppp will be filled with the page the return
	107	* value resides in.
	108	*
	109	* Returns:
	110	* The wanted direct on success, else a NULL pointer.
	111	*/
	112	static struct vxfs_direct *
	113	vxfs_find_entry(struct inode ip, struct dentry dp, struct page **ppp)
	114	{
	115	u_long npages, page, nblocks, pblocks, block;
	116	u_long bsize = ip->i_sb->s_blocksize;
	117	const char *name = dp->d_name.name;
	118	int namelen = dp->d_name.len;
	119
	120	npages = dir_pages(ip);
	121	nblocks = dir_blocks(ip);
	122	pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb);
	123
	124	for (page = 0; page < npages; page++) {
	125	caddr_t kaddr;
	126	struct page *pp;
	127
	128	pp = vxfs_get_page(ip->i_mapping, page);
	129	if (IS_ERR(pp))
	130	continue;
	131	kaddr = (caddr_t)page_address(pp);
	132
	133	for (block = 0; block <= nblocks && block <= pblocks; block++) {
	134	caddr_t baddr, limit;
	135	struct vxfs_dirblk *dbp;
	136	struct vxfs_direct *de;
	137
	138	baddr = kaddr + (block * bsize);
	139	limit = baddr + bsize - VXFS_DIRLEN(1);
	140
	141	dbp = (struct vxfs_dirblk *)baddr;
	142	de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp));
	143
	144	for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
	145	if (!de->d_reclen)
	146	break;
	147	if (!de->d_ino)
	148	continue;
	149	if (vxfs_match(namelen, name, de)) {
	150	*ppp = pp;
	151	return (de);
	152	}
	153	}
	154	}
	155	vxfs_put_page(pp);
	156	}
157
158	return NULL;
159	}
160
161	/**
162	* vxfs_inode_by_name - find inode number for dentry
163	* @dip: directory to search in
164	* @dp: dentry we seach for
165	*
166	* Description:
167	* vxfs_inode_by_name finds out the inode number of
168	* the path component described by @dp in @dip.
169	*
170	* Returns:
171	* The wanted inode number on success, else Zero.
172	*/
173	static ino_t
174	vxfs_inode_by_name(struct inode dip, struct dentry dp)
175	{
176	struct vxfs_direct *de;
177	struct page *pp;
178	ino_t ino = 0;
179
180	de = vxfs_find_entry(dip, dp, &pp);
181	if (de) {
182	ino = de->d_ino;
183	kunmap(pp);
184	page_cache_release(pp);
185	}
186
187	return (ino);
188	}
189
190	/**
191	* vxfs_lookup - lookup pathname component
192	* @dip: dir in which we lookup
193	* @dp: dentry we lookup
194	* @nd: lookup nameidata
195	*
196	* Description:
197	* vxfs_lookup tries to lookup the pathname component described
198	* by @dp in @dip.
199	*
200	* Returns:
201	* A NULL-pointer on success, else an negative error code encoded
202	* in the return pointer.
203	*/
204	static struct dentry *
205	vxfs_lookup(struct inode dip, struct dentry dp, struct nameidata *nd)
206	{
207	struct inode *ip = NULL;
208	ino_t ino;
209
210	if (dp->d_name.len > VXFS_NAMELEN)
211	return ERR_PTR(-ENAMETOOLONG);
212
213	lock_kernel();
214	ino = vxfs_inode_by_name(dip, dp);
215	if (ino) {
216	ip = iget(dip->i_sb, ino);
217	if (!ip) {
218	unlock_kernel();
219	return ERR_PTR(-EACCES);
220	}
221	}
222	unlock_kernel();
223	d_add(dp, ip);
224	return NULL;
225	}
226
227	/**
228	* vxfs_readdir - read a directory
229	* @fp: the directory to read
230	* @retp: return buffer
231	* @filler: filldir callback
232	*
233	* Description:
234	* vxfs_readdir fills @retp with directory entries from @fp
235	* using the VFS supplied callback @filler.
236	*
237	* Returns:
238	* Zero.
239	*/
240	static int
241	vxfs_readdir(struct file fp, void retp, filldir_t filler)
242	{
243	struct inode *ip = fp->f_dentry->d_inode;
244	struct super_block *sbp = ip->i_sb;
245	u_long bsize = sbp->s_blocksize;
246	u_long page, npages, block, pblocks, nblocks, offset;
247	loff_t pos;
248
249	switch ((long)fp->f_pos) {
250	case 0:
251	if (filler(retp, ".", 1, fp->f_pos, ip->i_ino, DT_DIR) < 0)
252	goto out;
253	fp->f_pos++;
254	/* fallthrough */
255	case 1:
256	if (filler(retp, "..", 2, fp->f_pos, VXFS_INO(ip)->vii_dotdot, DT_DIR) < 0)
257	goto out;
258	fp->f_pos++;
259	/* fallthrough */
260	}
261
262	pos = fp->f_pos - 2;
263
264	if (pos > VXFS_DIRROUND(ip->i_size)) {
265	unlock_kernel();
266	return 0;
267	}
268
269	npages = dir_pages(ip);
270	nblocks = dir_blocks(ip);
271	pblocks = VXFS_BLOCK_PER_PAGE(sbp);
272
273	page = pos >> PAGE_CACHE_SHIFT;
274	offset = pos & ~PAGE_CACHE_MASK;
275	block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks;
276
277	for (; page < npages; page++, block = 0) {
278	caddr_t kaddr;
279	struct page *pp;
280
281	pp = vxfs_get_page(ip->i_mapping, page);
282	if (IS_ERR(pp))
283	continue;
284	kaddr = (caddr_t)page_address(pp);
285
286	for (; block <= nblocks && block <= pblocks; block++) {
287	caddr_t baddr, limit;
288	struct vxfs_dirblk *dbp;
289	struct vxfs_direct *de;
290
291	baddr = kaddr + (block * bsize);
292	limit = baddr + bsize - VXFS_DIRLEN(1);
293
294	dbp = (struct vxfs_dirblk *)baddr;
295	de = (struct vxfs_direct *)
296	(offset ?
297	(kaddr + offset) :
298	(baddr + VXFS_DIRBLKOV(dbp)));
299
300	for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
301	int over;
302
303	if (!de->d_reclen)
304	break;
305	if (!de->d_ino)
306	continue;
307
308	offset = (caddr_t)de - kaddr;
309	over = filler(retp, de->d_name, de->d_namelen,
310	((page << PAGE_CACHE_SHIFT) \| offset) + 2,
311	de->d_ino, DT_UNKNOWN);
312	if (over) {
313	vxfs_put_page(pp);
314	goto done;
315	}
316	}
317	offset = 0;
318	}
319	vxfs_put_page(pp);
320	offset = 0;
321	}
322
323	done:
324	fp->f_pos = ((page << PAGE_CACHE_SHIFT) \| offset) + 2;
325	out:
326	unlock_kernel();
327	return 0;
328	}