aboutsummaryrefslogtreecommitdiffstats
path: root/fs/freevxfs/vxfs_lookup.c
blob: 506ae251d2c0195f4abeeb177a730d5869aeb79a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
/*
 * 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,
};

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;
}