121 строка
2.7 KiB
C
121 строка
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* namei.c
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*
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* Copyright (c) 1999 Al Smith
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*
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* Portions derived from work (c) 1995,1996 Christian Vogelgsang.
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*/
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#include <linux/buffer_head.h>
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#include <linux/string.h>
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#include <linux/exportfs.h>
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#include "efs.h"
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static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len)
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{
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struct buffer_head *bh;
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int slot, namelen;
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char *nameptr;
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struct efs_dir *dirblock;
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struct efs_dentry *dirslot;
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efs_ino_t inodenum;
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efs_block_t block;
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if (inode->i_size & (EFS_DIRBSIZE-1))
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pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
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__func__);
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for(block = 0; block < inode->i_blocks; block++) {
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bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
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if (!bh) {
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pr_err("%s(): failed to read dir block %d\n",
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__func__, block);
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return 0;
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}
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dirblock = (struct efs_dir *) bh->b_data;
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if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
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pr_err("%s(): invalid directory block\n", __func__);
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brelse(bh);
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return 0;
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}
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for (slot = 0; slot < dirblock->slots; slot++) {
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dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
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namelen = dirslot->namelen;
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nameptr = dirslot->name;
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if ((namelen == len) && (!memcmp(name, nameptr, len))) {
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inodenum = be32_to_cpu(dirslot->inode);
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brelse(bh);
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return inodenum;
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}
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}
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brelse(bh);
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}
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return 0;
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}
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struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
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{
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efs_ino_t inodenum;
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struct inode *inode = NULL;
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inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
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if (inodenum)
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inode = efs_iget(dir->i_sb, inodenum);
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return d_splice_alias(inode, dentry);
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}
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static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,
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u32 generation)
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{
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struct inode *inode;
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if (ino == 0)
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return ERR_PTR(-ESTALE);
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inode = efs_iget(sb, ino);
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if (IS_ERR(inode))
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return ERR_CAST(inode);
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if (generation && inode->i_generation != generation) {
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iput(inode);
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return ERR_PTR(-ESTALE);
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}
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return inode;
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}
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struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
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int fh_len, int fh_type)
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{
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return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
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efs_nfs_get_inode);
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}
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struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
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int fh_len, int fh_type)
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{
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return generic_fh_to_parent(sb, fid, fh_len, fh_type,
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efs_nfs_get_inode);
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}
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struct dentry *efs_get_parent(struct dentry *child)
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{
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struct dentry *parent = ERR_PTR(-ENOENT);
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efs_ino_t ino;
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ino = efs_find_entry(d_inode(child), "..", 2);
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if (ino)
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parent = d_obtain_alias(efs_iget(child->d_sb, ino));
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return parent;
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}
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