297 lines
7.2 KiB
C
297 lines
7.2 KiB
C
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/*
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* Copyright (c) 2000-2001 Christoph Hellwig.
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* Copyright (c) 2016 Krzysztof Blaszkowski
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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 "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_SIZE / (sbp)->s_blocksize))
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static struct dentry * vxfs_lookup(struct inode *, struct dentry *, unsigned int);
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static int vxfs_readdir(struct file *, struct dir_context *);
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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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.llseek = generic_file_llseek,
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.read = generic_read_dir,
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.iterate_shared = vxfs_readdir,
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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 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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loff_t limit = VXFS_DIRROUND(ip->i_size);
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struct vxfs_direct *de_exit = NULL;
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loff_t pos = 0;
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struct vxfs_sb_info *sbi = VXFS_SBI(ip->i_sb);
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while (pos < limit) {
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struct page *pp;
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char *kaddr;
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int pg_ofs = pos & ~PAGE_MASK;
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pp = vxfs_get_page(ip->i_mapping, pos >> PAGE_SHIFT);
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if (IS_ERR(pp))
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return NULL;
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kaddr = (char *)page_address(pp);
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while (pg_ofs < PAGE_SIZE && pos < limit) {
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struct vxfs_direct *de;
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if ((pos & (bsize - 1)) < 4) {
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struct vxfs_dirblk *dbp =
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(struct vxfs_dirblk *)
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(kaddr + (pos & ~PAGE_MASK));
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int overhead = VXFS_DIRBLKOV(sbi, dbp);
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pos += overhead;
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pg_ofs += overhead;
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}
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de = (struct vxfs_direct *)(kaddr + pg_ofs);
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if (!de->d_reclen) {
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pos += bsize - 1;
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pos &= ~(bsize - 1);
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break;
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}
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pg_ofs += fs16_to_cpu(sbi, de->d_reclen);
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pos += fs16_to_cpu(sbi, de->d_reclen);
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if (!de->d_ino)
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continue;
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if (namelen != fs16_to_cpu(sbi, de->d_namelen))
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continue;
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if (!memcmp(name, de->d_name, namelen)) {
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*ppp = pp;
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de_exit = de;
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break;
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}
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}
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if (!de_exit)
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vxfs_put_page(pp);
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else
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break;
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}
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return de_exit;
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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 search 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 = fs32_to_cpu(VXFS_SBI(dip->i_sb), de->d_ino);
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kunmap(pp);
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put_page(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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* @flags: lookup flags
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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 a 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, unsigned int flags)
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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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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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return d_splice_alias(ip, dp);
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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, struct dir_context *ctx)
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{
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struct inode *ip = file_inode(fp);
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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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loff_t pos, limit;
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struct vxfs_sb_info *sbi = VXFS_SBI(sbp);
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if (ctx->pos == 0) {
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if (!dir_emit_dot(fp, ctx))
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goto out;
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ctx->pos++;
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}
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if (ctx->pos == 1) {
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if (!dir_emit(ctx, "..", 2, VXFS_INO(ip)->vii_dotdot, DT_DIR))
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goto out;
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ctx->pos++;
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}
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limit = VXFS_DIRROUND(ip->i_size);
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if (ctx->pos > limit)
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goto out;
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pos = ctx->pos & ~3L;
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while (pos < limit) {
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struct page *pp;
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char *kaddr;
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int pg_ofs = pos & ~PAGE_MASK;
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int rc = 0;
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pp = vxfs_get_page(ip->i_mapping, pos >> PAGE_SHIFT);
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if (IS_ERR(pp))
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return -ENOMEM;
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kaddr = (char *)page_address(pp);
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while (pg_ofs < PAGE_SIZE && pos < limit) {
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struct vxfs_direct *de;
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if ((pos & (bsize - 1)) < 4) {
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struct vxfs_dirblk *dbp =
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(struct vxfs_dirblk *)
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(kaddr + (pos & ~PAGE_MASK));
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int overhead = VXFS_DIRBLKOV(sbi, dbp);
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pos += overhead;
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pg_ofs += overhead;
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}
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de = (struct vxfs_direct *)(kaddr + pg_ofs);
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if (!de->d_reclen) {
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pos += bsize - 1;
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pos &= ~(bsize - 1);
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break;
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}
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pg_ofs += fs16_to_cpu(sbi, de->d_reclen);
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pos += fs16_to_cpu(sbi, de->d_reclen);
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if (!de->d_ino)
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continue;
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rc = dir_emit(ctx, de->d_name,
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fs16_to_cpu(sbi, de->d_namelen),
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fs32_to_cpu(sbi, de->d_ino),
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DT_UNKNOWN);
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if (!rc) {
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/* the dir entry was not read, fix pos. */
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pos -= fs16_to_cpu(sbi, de->d_reclen);
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break;
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}
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}
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vxfs_put_page(pp);
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if (!rc)
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break;
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}
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ctx->pos = pos | 2;
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out:
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return 0;
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}
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