1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * namei.c 4 * 5 * Copyright (c) 1999 Al Smith 6 * 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 16 static 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 65 struct 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 77 static 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 96 struct 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 } 102 103 struct 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 } 109 110 struct 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