1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/affs/dir.c 4 * 5 * (c) 1996 Hans-Joachim Widmaier - Rewritten 6 * 7 * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem. 8 * 9 * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. 10 * 11 * (C) 1991 Linus Torvalds - minix filesystem 12 * 13 * affs directory handling functions 14 * 15 */ 16 17 #include <linux/iversion.h> 18 #include "affs.h" 19 20 static int affs_readdir(struct file *, struct dir_context *); 21 22 const struct file_operations affs_dir_operations = { 23 .read = generic_read_dir, 24 .llseek = generic_file_llseek, 25 .iterate_shared = affs_readdir, 26 .fsync = affs_file_fsync, 27 }; 28 29 /* 30 * directories can handle most operations... 31 */ 32 const struct inode_operations affs_dir_inode_operations = { 33 .create = affs_create, 34 .lookup = affs_lookup, 35 .link = affs_link, 36 .unlink = affs_unlink, 37 .symlink = affs_symlink, 38 .mkdir = affs_mkdir, 39 .rmdir = affs_rmdir, 40 .rename = affs_rename2, 41 .setattr = affs_notify_change, 42 }; 43 44 static int 45 affs_readdir(struct file *file, struct dir_context *ctx) 46 { 47 struct inode *inode = file_inode(file); 48 struct super_block *sb = inode->i_sb; 49 struct buffer_head *dir_bh = NULL; 50 struct buffer_head *fh_bh = NULL; 51 unsigned char *name; 52 int namelen; 53 u32 i; 54 int hash_pos; 55 int chain_pos; 56 u32 ino; 57 int error = 0; 58 59 pr_debug("%s(ino=%lu,f_pos=%llx)\n", __func__, inode->i_ino, ctx->pos); 60 61 if (ctx->pos < 2) { 62 file->private_data = (void *)0; 63 if (!dir_emit_dots(file, ctx)) 64 return 0; 65 } 66 67 affs_lock_dir(inode); 68 chain_pos = (ctx->pos - 2) & 0xffff; 69 hash_pos = (ctx->pos - 2) >> 16; 70 if (chain_pos == 0xffff) { 71 affs_warning(sb, "readdir", "More than 65535 entries in chain"); 72 chain_pos = 0; 73 hash_pos++; 74 ctx->pos = ((hash_pos << 16) | chain_pos) + 2; 75 } 76 dir_bh = affs_bread(sb, inode->i_ino); 77 if (!dir_bh) 78 goto out_unlock_dir; 79 80 /* If the directory hasn't changed since the last call to readdir(), 81 * we can jump directly to where we left off. 82 */ 83 ino = (u32)(long)file->private_data; 84 if (ino && inode_eq_iversion(inode, file->f_version)) { 85 pr_debug("readdir() left off=%d\n", ino); 86 goto inside; 87 } 88 89 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 90 for (i = 0; ino && i < chain_pos; i++) { 91 fh_bh = affs_bread(sb, ino); 92 if (!fh_bh) { 93 affs_error(sb, "readdir","Cannot read block %d", i); 94 error = -EIO; 95 goto out_brelse_dir; 96 } 97 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 98 affs_brelse(fh_bh); 99 fh_bh = NULL; 100 } 101 if (ino) 102 goto inside; 103 hash_pos++; 104 105 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) { 106 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 107 if (!ino) 108 continue; 109 ctx->pos = (hash_pos << 16) + 2; 110 inside: 111 do { 112 fh_bh = affs_bread(sb, ino); 113 if (!fh_bh) { 114 affs_error(sb, "readdir", 115 "Cannot read block %d", ino); 116 break; 117 } 118 119 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], 120 (u8)AFFSNAMEMAX); 121 name = AFFS_TAIL(sb, fh_bh)->name + 1; 122 pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n", 123 namelen, name, ino, hash_pos, ctx->pos); 124 125 if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN)) 126 goto done; 127 ctx->pos++; 128 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 129 affs_brelse(fh_bh); 130 fh_bh = NULL; 131 } while (ino); 132 } 133 done: 134 file->f_version = inode_query_iversion(inode); 135 file->private_data = (void *)(long)ino; 136 affs_brelse(fh_bh); 137 138 out_brelse_dir: 139 affs_brelse(dir_bh); 140 141 out_unlock_dir: 142 affs_unlock_dir(inode); 143 return error; 144 } 145