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

/*
 * Copyright (c) 2000-2001 Christoph Hellwig.
 * Copyright (c) 2016 Krzysztof Blaszkowski
 * 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_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_shared =	vxfs_readdir,
};


/**
 * 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 bsize = ip->i_sb->s_blocksize;
	const char *name = dp->d_name.name;
	int namelen = dp->d_name.len;
	loff_t limit = VXFS_DIRROUND(ip->i_size);
	struct vxfs_direct *de_exit = NULL;
	loff_t pos = 0;
	struct vxfs_sb_info *sbi = VXFS_SBI(ip->i_sb);

	while (pos < limit) {
		struct page *pp;
		char *kaddr;
		int pg_ofs = pos & ~PAGE_MASK;

		pp = vxfs_get_page(ip->i_mapping, pos >> PAGE_SHIFT);
		if (IS_ERR(pp))
			return NULL;
		kaddr = (char *)page_address(pp);

		while (pg_ofs < PAGE_SIZE && pos < limit) {
			struct vxfs_direct *de;

			if ((pos & (bsize - 1)) < 4) {
				struct vxfs_dirblk *dbp =
					(struct vxfs_dirblk *)
					 (kaddr + (pos & ~PAGE_MASK));
				int overhead = VXFS_DIRBLKOV(sbi, dbp);

				pos += overhead;
				pg_ofs += overhead;
			}
			de = (struct vxfs_direct *)(kaddr + pg_ofs);

			if (!de->d_reclen) {
				pos += bsize - 1;
				pos &= ~(bsize - 1);
				break;
			}

			pg_ofs += fs16_to_cpu(sbi, de->d_reclen);
			pos += fs16_to_cpu(sbi, de->d_reclen);
			if (!de->d_ino)
				continue;

			if (namelen != fs16_to_cpu(sbi, de->d_namelen))
				continue;
			if (!memcmp(name, de->d_name, namelen)) {
				*ppp = pp;
				de_exit = de;
				break;
			}
		}
		if (!de_exit)
			vxfs_put_page(pp);
		else
			break;
	}

	return de_exit;
}

/**
 * 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 = fs32_to_cpu(VXFS_SBI(dip->i_sb), de->d_ino);
		kunmap(pp);
		put_page(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 a 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);
	return d_splice_alias(ip, dp);
}

/**
 * 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;
	loff_t			pos, limit;
	struct vxfs_sb_info	*sbi = VXFS_SBI(sbp);

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

	limit = VXFS_DIRROUND(ip->i_size);
	if (ctx->pos > limit)
		goto out;

	pos = ctx->pos & ~3L;

	while (pos < limit) {
		struct page *pp;
		char *kaddr;
		int pg_ofs = pos & ~PAGE_MASK;
		int rc = 0;

		pp = vxfs_get_page(ip->i_mapping, pos >> PAGE_SHIFT);
		if (IS_ERR(pp))
			return -ENOMEM;

		kaddr = (char *)page_address(pp);

		while (pg_ofs < PAGE_SIZE && pos < limit) {
			struct vxfs_direct *de;

			if ((pos & (bsize - 1)) < 4) {
				struct vxfs_dirblk *dbp =
					(struct vxfs_dirblk *)
					 (kaddr + (pos & ~PAGE_MASK));
				int overhead = VXFS_DIRBLKOV(sbi, dbp);

				pos += overhead;
				pg_ofs += overhead;
			}
			de = (struct vxfs_direct *)(kaddr + pg_ofs);

			if (!de->d_reclen) {
				pos += bsize - 1;
				pos &= ~(bsize - 1);
				break;
			}

			pg_ofs += fs16_to_cpu(sbi, de->d_reclen);
			pos += fs16_to_cpu(sbi, de->d_reclen);
			if (!de->d_ino)
				continue;

			rc = dir_emit(ctx, de->d_name,
					fs16_to_cpu(sbi, de->d_namelen),
					fs32_to_cpu(sbi, de->d_ino),
					DT_UNKNOWN);
			if (!rc) {
				/* the dir entry was not read, fix pos. */
				pos -= fs16_to_cpu(sbi, de->d_reclen);
				break;
			}
		}
		vxfs_put_page(pp);
		if (!rc)
			break;
	}

	ctx->pos = pos | 2;

out:
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* Copyright (c) 2000-2001 Christoph Hellwig.
1cce1701	3	* Copyright (c) 2016 Krzysztof Blaszkowski
1da177e4 LT	4	* All rights reserved.
	5	*
	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice, this list of conditions, and the following disclaimer,
	11	* without modification.
	12	* 2. The name of the author may not be used to endorse or promote products
	13	* derived from this software without specific prior written permission.
	14	*
	15	* Alternatively, this software may be distributed under the terms of the
	16	* GNU General Public License ("GPL").
	17	*
	18	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	19	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	20	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	21	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
	22	* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	23	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	24	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	25	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	26	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	27	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	28	* SUCH DAMAGE.
	29	*/
	30
	31	/*
	32	* Veritas filesystem driver - lookup and other directory related code.
	33	*/
	34	#include <linux/fs.h>
	35	#include <linux/time.h>
	36	#include <linux/mm.h>
	37	#include <linux/highmem.h>
	38	#include <linux/kernel.h>
	39	#include <linux/pagemap.h>
1da177e4 LT	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	*/
09cbfeaf	49	#define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_SIZE / (sbp)->s_blocksize))
1da177e4 LT	50
1da177e4 LT	51
00cd8dd3	52	static struct dentry * vxfs_lookup(struct inode , struct dentry , unsigned int);
9b5d5a17	53	static int vxfs_readdir(struct file , struct dir_context );
1da177e4	54
754661f1	55	const struct inode_operations vxfs_dir_inode_ops = {
1da177e4 LT	56	.lookup = vxfs_lookup,
	57	};
	58
4b6f5d20	59	const struct file_operations vxfs_dir_operations = {
ca572727 B	60	.llseek = generic_file_llseek,
ca572727 B	61	.read = generic_read_dir,
c51da20c	62	.iterate_shared = vxfs_readdir,
1da177e4 LT	63	};
1da177e4 LT	64
1da177e4 LT	65
	66	/**
	67	* vxfs_find_entry - find a mathing directory entry for a dentry
	68	* @ip: directory inode
	69	* @dp: dentry for which we want to find a direct
	70	* @ppp: gets filled with the page the return value sits in
	71	*
	72	* Description:
	73	* vxfs_find_entry finds a &struct vxfs_direct for the VFS directory
	74	* cache entry @dp. @ppp will be filled with the page the return
	75	* value resides in.
	76	*
	77	* Returns:
	78	* The wanted direct on success, else a NULL pointer.
	79	*/
	80	static struct vxfs_direct *
	81	vxfs_find_entry(struct inode ip, struct dentry dp, struct page **ppp)
	82	{
12495ea3 KB	83	u_long bsize = ip->i_sb->s_blocksize;
	84	const char *name = dp->d_name.name;
	85	int namelen = dp->d_name.len;
	86	loff_t limit = VXFS_DIRROUND(ip->i_size);
	87	struct vxfs_direct *de_exit = NULL;
	88	loff_t pos = 0;
	89	struct vxfs_sb_info *sbi = VXFS_SBI(ip->i_sb);
	90
	91	while (pos < limit) {
	92	struct page *pp;
	93	char *kaddr;
	94	int pg_ofs = pos & ~PAGE_MASK;
1da177e4	95
12495ea3	96	pp = vxfs_get_page(ip->i_mapping, pos >> PAGE_SHIFT);
1da177e4	97	if (IS_ERR(pp))
12495ea3 KB	98	return NULL;
	99	kaddr = (char *)page_address(pp);
	100
	101	while (pg_ofs < PAGE_SIZE && pos < limit) {
	102	struct vxfs_direct *de;
	103
	104	if ((pos & (bsize - 1)) < 4) {
	105	struct vxfs_dirblk *dbp =
	106	(struct vxfs_dirblk *)
	107	(kaddr + (pos & ~PAGE_MASK));
	108	int overhead = VXFS_DIRBLKOV(sbi, dbp);
	109
	110	pos += overhead;
	111	pg_ofs += overhead;
	112	}
	113	de = (struct vxfs_direct *)(kaddr + pg_ofs);
	114
	115	if (!de->d_reclen) {
	116	pos += bsize - 1;
	117	pos &= ~(bsize - 1);
	118	break;
	119	}
	120
	121	pg_ofs += fs16_to_cpu(sbi, de->d_reclen);
	122	pos += fs16_to_cpu(sbi, de->d_reclen);
	123	if (!de->d_ino)
	124	continue;
	125
	126	if (namelen != fs16_to_cpu(sbi, de->d_namelen))
	127	continue;
	128	if (!memcmp(name, de->d_name, namelen)) {
	129	*ppp = pp;
	130	de_exit = de;
	131	break;
1da177e4 LT	132	}
1da177e4 LT	133	}
12495ea3 KB	134	if (!de_exit)
	135	vxfs_put_page(pp);
	136	else
	137	break;
1da177e4 LT	138	}
1da177e4 LT	139
12495ea3	140	return de_exit;
1da177e4 LT	141	}
	142
	143	/**
	144	* vxfs_inode_by_name - find inode number for dentry
	145	* @dip: directory to search in
25985edc	146	* @dp: dentry we search for
1da177e4 LT	147	*
	148	* Description:
	149	* vxfs_inode_by_name finds out the inode number of
	150	* the path component described by @dp in @dip.
	151	*
	152	* Returns:
	153	* The wanted inode number on success, else Zero.
	154	*/
	155	static ino_t
	156	vxfs_inode_by_name(struct inode dip, struct dentry dp)
	157	{
	158	struct vxfs_direct *de;
	159	struct page *pp;
	160	ino_t ino = 0;
	161
	162	de = vxfs_find_entry(dip, dp, &pp);
	163	if (de) {
0d83f7fc	164	ino = fs32_to_cpu(VXFS_SBI(dip->i_sb), de->d_ino);
1da177e4	165	kunmap(pp);
09cbfeaf	166	put_page(pp);
1da177e4 LT	167	}
	168
	169	return (ino);
	170	}
	171
	172	/**
	173	* vxfs_lookup - lookup pathname component
	174	* @dip: dir in which we lookup
	175	* @dp: dentry we lookup
ddae82d8	176	* @flags: lookup flags
1da177e4 LT	177	*
	178	* Description:
	179	* vxfs_lookup tries to lookup the pathname component described
	180	* by @dp in @dip.
	181	*
	182	* Returns:
eaf593c3	183	* A NULL-pointer on success, else a negative error code encoded
1da177e4 LT	184	* in the return pointer.
	185	*/
	186	static struct dentry *
00cd8dd3	187	vxfs_lookup(struct inode dip, struct dentry dp, unsigned int flags)
1da177e4 LT	188	{
	189	struct inode *ip = NULL;
	190	ino_t ino;
	191
	192	if (dp->d_name.len > VXFS_NAMELEN)
	193	return ERR_PTR(-ENAMETOOLONG);
	194
1da177e4	195	ino = vxfs_inode_by_name(dip, dp);
72ff0b03	196	if (ino)
d0b07948	197	ip = vxfs_iget(dip->i_sb, ino);
72ff0b03	198	return d_splice_alias(ip, dp);
1da177e4 LT	199	}
	200
	201	/**
	202	* vxfs_readdir - read a directory
	203	* @fp: the directory to read
	204	* @retp: return buffer
	205	* @filler: filldir callback
	206	*
	207	* Description:
	208	* vxfs_readdir fills @retp with directory entries from @fp
	209	* using the VFS supplied callback @filler.
	210	*
	211	* Returns:
	212	* Zero.
	213	*/
	214	static int
9b5d5a17	215	vxfs_readdir(struct file fp, struct dir_context ctx)
1da177e4	216	{
496ad9aa	217	struct inode *ip = file_inode(fp);
1da177e4 LT	218	struct super_block *sbp = ip->i_sb;
1da177e4 LT	219	u_long bsize = sbp->s_blocksize;
12495ea3 KB	220	loff_t pos, limit;
12495ea3 KB	221	struct vxfs_sb_info *sbi = VXFS_SBI(sbp);
0d83f7fc	222
9b5d5a17 AV	223	if (ctx->pos == 0) {
9b5d5a17 AV	224	if (!dir_emit_dot(fp, ctx))
12495ea3 KB	225	goto out;
12495ea3 KB	226	ctx->pos++;
1da177e4	227	}
9b5d5a17 AV	228	if (ctx->pos == 1) {
9b5d5a17 AV	229	if (!dir_emit(ctx, "..", 2, VXFS_INO(ip)->vii_dotdot, DT_DIR))
12495ea3 KB	230	goto out;
12495ea3 KB	231	ctx->pos++;
9b5d5a17	232	}
1da177e4	233
12495ea3 KB	234	limit = VXFS_DIRROUND(ip->i_size);
	235	if (ctx->pos > limit)
	236	goto out;
1da177e4	237
12495ea3	238	pos = ctx->pos & ~3L;
1da177e4	239
12495ea3 KB	240	while (pos < limit) {
	241	struct page *pp;
	242	char *kaddr;
	243	int pg_ofs = pos & ~PAGE_MASK;
	244	int rc = 0;
1da177e4	245
12495ea3	246	pp = vxfs_get_page(ip->i_mapping, pos >> PAGE_SHIFT);
1da177e4	247	if (IS_ERR(pp))
12495ea3 KB	248	return -ENOMEM;
12495ea3 KB	249
9b5d5a17	250	kaddr = (char *)page_address(pp);
1da177e4	251
12495ea3 KB	252	while (pg_ofs < PAGE_SIZE && pos < limit) {
12495ea3 KB	253	struct vxfs_direct *de;
1da177e4	254
12495ea3 KB	255	if ((pos & (bsize - 1)) < 4) {
	256	struct vxfs_dirblk *dbp =
	257	(struct vxfs_dirblk *)
	258	(kaddr + (pos & ~PAGE_MASK));
	259	int overhead = VXFS_DIRBLKOV(sbi, dbp);
	260
	261	pos += overhead;
	262	pg_ofs += overhead;
	263	}
	264	de = (struct vxfs_direct *)(kaddr + pg_ofs);
	265
	266	if (!de->d_reclen) {
	267	pos += bsize - 1;
	268	pos &= ~(bsize - 1);
	269	break;
	270	}
	271
	272	pg_ofs += fs16_to_cpu(sbi, de->d_reclen);
	273	pos += fs16_to_cpu(sbi, de->d_reclen);
	274	if (!de->d_ino)
	275	continue;
	276
	277	rc = dir_emit(ctx, de->d_name,
	278	fs16_to_cpu(sbi, de->d_namelen),
	279	fs32_to_cpu(sbi, de->d_ino),
	280	DT_UNKNOWN);
	281	if (!rc) {
	282	/* the dir entry was not read, fix pos. */
	283	pos -= fs16_to_cpu(sbi, de->d_reclen);
	284	break;
1da177e4	285	}
1da177e4 LT	286	}
1da177e4 LT	287	vxfs_put_page(pp);
12495ea3 KB	288	if (!rc)
12495ea3 KB	289	break;
1da177e4	290	}
12495ea3 KB	291
	292	ctx->pos = pos \| 2;
	293
	294	out:
1da177e4 LT	295	return 0;
1da177e4 LT	296	}