121 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * namei.c4 *5 * Copyright (c) 1999 Al Smith6 *7 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.8 */9 10#include <linux/buffer_head.h>11#include <linux/string.h>12#include <linux/exportfs.h>13#include "efs.h"14 15 16static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len)17{18 struct buffer_head *bh;19 20 int slot, namelen;21 char *nameptr;22 struct efs_dir *dirblock;23 struct efs_dentry *dirslot;24 efs_ino_t inodenum;25 efs_block_t block;26 27 if (inode->i_size & (EFS_DIRBSIZE-1))28 pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",29 __func__);30 31 for(block = 0; block < inode->i_blocks; block++) {32 33 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));34 if (!bh) {35 pr_err("%s(): failed to read dir block %d\n",36 __func__, block);37 return 0;38 }39 40 dirblock = (struct efs_dir *) bh->b_data;41 42 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {43 pr_err("%s(): invalid directory block\n", __func__);44 brelse(bh);45 return 0;46 }47 48 for (slot = 0; slot < dirblock->slots; slot++) {49 dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));50 51 namelen = dirslot->namelen;52 nameptr = dirslot->name;53 54 if ((namelen == len) && (!memcmp(name, nameptr, len))) {55 inodenum = be32_to_cpu(dirslot->inode);56 brelse(bh);57 return inodenum;58 }59 }60 brelse(bh);61 }62 return 0;63}64 65struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)66{67 efs_ino_t inodenum;68 struct inode *inode = NULL;69 70 inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);71 if (inodenum)72 inode = efs_iget(dir->i_sb, inodenum);73 74 return d_splice_alias(inode, dentry);75}76 77static struct inode *efs_nfs_get_inode(struct super_block *sb, u64 ino,78 u32 generation)79{80 struct inode *inode;81 82 if (ino == 0)83 return ERR_PTR(-ESTALE);84 inode = efs_iget(sb, ino);85 if (IS_ERR(inode))86 return ERR_CAST(inode);87 88 if (generation && inode->i_generation != generation) {89 iput(inode);90 return ERR_PTR(-ESTALE);91 }92 93 return inode;94}95 96struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,97 int fh_len, int fh_type)98{99 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,100 efs_nfs_get_inode);101}102 103struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,104 int fh_len, int fh_type)105{106 return generic_fh_to_parent(sb, fid, fh_len, fh_type,107 efs_nfs_get_inode);108}109 110struct dentry *efs_get_parent(struct dentry *child)111{112 struct dentry *parent = ERR_PTR(-ENOENT);113 efs_ino_t ino;114 115 ino = efs_find_entry(d_inode(child), "..", 2);116 if (ino)117 parent = d_obtain_alias(efs_iget(child->d_sb, ino));118 119 return parent;120}121