| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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 | } |