331 lines
8.0 KiB
C
331 lines
8.0 KiB
C
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/*
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* Copyright (c) 2000-2001 Christoph Hellwig.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL").
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Veritas filesystem driver - lookup and other directory related code.
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*/
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#include <linux/fs.h>
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#include <linux/time.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/kernel.h>
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#include <linux/pagemap.h>
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#include <linux/smp_lock.h>
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#include "vxfs.h"
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#include "vxfs_dir.h"
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#include "vxfs_inode.h"
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#include "vxfs_extern.h"
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/*
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* Number of VxFS blocks per page.
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*/
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#define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_CACHE_SIZE / (sbp)->s_blocksize))
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static struct dentry * vxfs_lookup(struct inode *, struct dentry *, struct nameidata *);
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static int vxfs_readdir(struct file *, void *, filldir_t);
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const struct inode_operations vxfs_dir_inode_ops = {
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.lookup = vxfs_lookup,
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};
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const struct file_operations vxfs_dir_operations = {
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.readdir = vxfs_readdir,
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};
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static inline u_long
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dir_pages(struct inode *inode)
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{
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return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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}
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static inline u_long
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dir_blocks(struct inode *ip)
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{
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u_long bsize = ip->i_sb->s_blocksize;
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return (ip->i_size + bsize - 1) & ~(bsize - 1);
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}
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/*
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* NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure.
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*
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* len <= VXFS_NAMELEN and de != NULL are guaranteed by caller.
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*/
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static inline int
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vxfs_match(int len, const char * const name, struct vxfs_direct *de)
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{
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if (len != de->d_namelen)
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return 0;
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if (!de->d_ino)
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return 0;
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return !memcmp(name, de->d_name, len);
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}
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static inline struct vxfs_direct *
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vxfs_next_entry(struct vxfs_direct *de)
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{
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return ((struct vxfs_direct *)((char*)de + de->d_reclen));
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}
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/**
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* vxfs_find_entry - find a mathing directory entry for a dentry
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* @ip: directory inode
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* @dp: dentry for which we want to find a direct
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* @ppp: gets filled with the page the return value sits in
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*
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* Description:
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* vxfs_find_entry finds a &struct vxfs_direct for the VFS directory
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* cache entry @dp. @ppp will be filled with the page the return
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* value resides in.
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*
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* Returns:
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* The wanted direct on success, else a NULL pointer.
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*/
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static struct vxfs_direct *
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vxfs_find_entry(struct inode *ip, struct dentry *dp, struct page **ppp)
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{
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u_long npages, page, nblocks, pblocks, block;
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u_long bsize = ip->i_sb->s_blocksize;
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const char *name = dp->d_name.name;
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int namelen = dp->d_name.len;
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npages = dir_pages(ip);
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nblocks = dir_blocks(ip);
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pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb);
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for (page = 0; page < npages; page++) {
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caddr_t kaddr;
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struct page *pp;
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pp = vxfs_get_page(ip->i_mapping, page);
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if (IS_ERR(pp))
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continue;
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kaddr = (caddr_t)page_address(pp);
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for (block = 0; block <= nblocks && block <= pblocks; block++) {
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caddr_t baddr, limit;
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struct vxfs_dirblk *dbp;
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struct vxfs_direct *de;
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baddr = kaddr + (block * bsize);
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limit = baddr + bsize - VXFS_DIRLEN(1);
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dbp = (struct vxfs_dirblk *)baddr;
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de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp));
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for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
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if (!de->d_reclen)
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break;
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if (!de->d_ino)
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continue;
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if (vxfs_match(namelen, name, de)) {
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*ppp = pp;
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return (de);
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}
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}
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}
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vxfs_put_page(pp);
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}
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return NULL;
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}
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/**
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* vxfs_inode_by_name - find inode number for dentry
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* @dip: directory to search in
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* @dp: dentry we seach for
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*
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* Description:
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* vxfs_inode_by_name finds out the inode number of
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* the path component described by @dp in @dip.
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*
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* Returns:
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* The wanted inode number on success, else Zero.
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*/
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static ino_t
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vxfs_inode_by_name(struct inode *dip, struct dentry *dp)
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{
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struct vxfs_direct *de;
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struct page *pp;
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ino_t ino = 0;
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de = vxfs_find_entry(dip, dp, &pp);
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if (de) {
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ino = de->d_ino;
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kunmap(pp);
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page_cache_release(pp);
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}
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return (ino);
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}
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/**
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* vxfs_lookup - lookup pathname component
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* @dip: dir in which we lookup
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* @dp: dentry we lookup
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* @nd: lookup nameidata
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*
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* Description:
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* vxfs_lookup tries to lookup the pathname component described
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* by @dp in @dip.
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*
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* Returns:
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* A NULL-pointer on success, else an negative error code encoded
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* in the return pointer.
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*/
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static struct dentry *
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vxfs_lookup(struct inode *dip, struct dentry *dp, struct nameidata *nd)
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{
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struct inode *ip = NULL;
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ino_t ino;
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if (dp->d_name.len > VXFS_NAMELEN)
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return ERR_PTR(-ENAMETOOLONG);
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lock_kernel();
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ino = vxfs_inode_by_name(dip, dp);
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if (ino) {
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ip = vxfs_iget(dip->i_sb, ino);
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if (IS_ERR(ip)) {
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unlock_kernel();
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return ERR_CAST(ip);
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}
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}
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unlock_kernel();
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d_add(dp, ip);
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return NULL;
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}
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/**
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* vxfs_readdir - read a directory
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* @fp: the directory to read
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* @retp: return buffer
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* @filler: filldir callback
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*
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* Description:
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* vxfs_readdir fills @retp with directory entries from @fp
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* using the VFS supplied callback @filler.
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*
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* Returns:
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* Zero.
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*/
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static int
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vxfs_readdir(struct file *fp, void *retp, filldir_t filler)
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{
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struct inode *ip = fp->f_path.dentry->d_inode;
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struct super_block *sbp = ip->i_sb;
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u_long bsize = sbp->s_blocksize;
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u_long page, npages, block, pblocks, nblocks, offset;
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loff_t pos;
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lock_kernel();
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switch ((long)fp->f_pos) {
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case 0:
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if (filler(retp, ".", 1, fp->f_pos, ip->i_ino, DT_DIR) < 0)
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goto out;
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fp->f_pos++;
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/* fallthrough */
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case 1:
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if (filler(retp, "..", 2, fp->f_pos, VXFS_INO(ip)->vii_dotdot, DT_DIR) < 0)
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goto out;
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fp->f_pos++;
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/* fallthrough */
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}
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pos = fp->f_pos - 2;
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if (pos > VXFS_DIRROUND(ip->i_size)) {
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unlock_kernel();
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return 0;
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}
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npages = dir_pages(ip);
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nblocks = dir_blocks(ip);
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pblocks = VXFS_BLOCK_PER_PAGE(sbp);
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page = pos >> PAGE_CACHE_SHIFT;
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offset = pos & ~PAGE_CACHE_MASK;
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block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks;
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for (; page < npages; page++, block = 0) {
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caddr_t kaddr;
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struct page *pp;
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pp = vxfs_get_page(ip->i_mapping, page);
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if (IS_ERR(pp))
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continue;
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kaddr = (caddr_t)page_address(pp);
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for (; block <= nblocks && block <= pblocks; block++) {
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caddr_t baddr, limit;
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struct vxfs_dirblk *dbp;
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struct vxfs_direct *de;
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baddr = kaddr + (block * bsize);
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limit = baddr + bsize - VXFS_DIRLEN(1);
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dbp = (struct vxfs_dirblk *)baddr;
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de = (struct vxfs_direct *)
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(offset ?
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(kaddr + offset) :
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(baddr + VXFS_DIRBLKOV(dbp)));
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for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
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int over;
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if (!de->d_reclen)
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break;
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if (!de->d_ino)
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continue;
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offset = (caddr_t)de - kaddr;
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over = filler(retp, de->d_name, de->d_namelen,
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((page << PAGE_CACHE_SHIFT) | offset) + 2,
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de->d_ino, DT_UNKNOWN);
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if (over) {
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vxfs_put_page(pp);
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goto done;
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}
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}
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offset = 0;
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}
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vxfs_put_page(pp);
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offset = 0;
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}
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done:
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fp->f_pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
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out:
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unlock_kernel();
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return 0;
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}
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