patch-2.4.5 linux/fs/freevxfs/vxfs_lookup.c

• Lines: 324
• Date: Mon May 21 12:31:06 2001
• Orig file: v2.4.4/linux/fs/freevxfs/vxfs_lookup.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.4/linux/fs/freevxfs/vxfs_lookup.c linux/fs/freevxfs/vxfs_lookup.c
@@ -0,0 +1,323 @@
+/*
+ * 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.
+ */
+
+#ident "$Id: vxfs_lookup.c,v 1.17 2001/05/21 15:23:53 hch Exp hch $"
+
+/*
+ * Veritas filesystem driver - lookup and other directory related code.
+ */
+#include <linux/fs.h>
+#include <linux/sched.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 *);
+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, 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
+ *
+ * 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 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 == 0)
+		return NULL;
+
+	ip = iget(dip->i_sb, ino);
+	if (!ip)
+		return ERR_PTR(-EACCES);
+	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, nblocks, offset;
+	loff_t			pos;
+	int			pblocks;
+
+	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))
+		return 0;
+
+	page = pos >> PAGE_CACHE_SHIFT;
+	offset = pos & ~PAGE_CACHE_MASK;
+	block = pos >> sbp->s_blocksize_bits;
+
+	npages = dir_pages(ip);
+	nblocks = dir_blocks(ip);
+	pblocks = VXFS_BLOCK_PER_PAGE(sbp);
+
+	for (; page < npages; page++, block = 0) {
+		caddr_t			kaddr;
+		struct page		*pp;
+
+		pp = vxfs_get_page(ip, 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;
+				}
+			}
+		}
+		vxfs_put_page(pp);
+		offset = 0;
+	}
+
+done:
+	fp->f_pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
+out:
+	fp->f_version = ip->i_version;
+	return 0;
+}