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