// SPDX-License-Identifier: GPL-2.0 /* * linux/fs/affs/dir.c * * (c) 1996 Hans-Joachim Widmaier - Rewritten * * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem. * * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. * * (C) 1991 Linus Torvalds - minix filesystem * * affs directory handling functions * */ #include <linux/iversion.h> #include "affs.h" static int affs_readdir(struct file *, struct dir_context *); const struct file_operations affs_dir_operations = { .read = generic_read_dir, .llseek = generic_file_llseek, .iterate_shared = affs_readdir, .fsync = affs_file_fsync, }; /* * directories can handle most operations... */ const struct inode_operations affs_dir_inode_operations = { .create = affs_create, .lookup = affs_lookup, .link = affs_link, .unlink = affs_unlink, .symlink = affs_symlink, .mkdir = affs_mkdir, .rmdir = affs_rmdir, .rename = affs_rename2, .setattr = affs_notify_change, }; static int affs_readdir(struct file *file, struct dir_context *ctx) { struct inode *inode = file_inode(file); struct super_block *sb = inode->i_sb; struct buffer_head *dir_bh = NULL; struct buffer_head *fh_bh = NULL; unsigned char *name; int namelen; u32 i; int hash_pos; int chain_pos; u32 ino; int error = 0; pr_debug("%s(ino=%lu,f_pos=%llx)\n", __func__, inode->i_ino, ctx->pos); if (ctx->pos < 2) { file->private_data = (void *)0; if (!dir_emit_dots(file, ctx)) return 0; } affs_lock_dir(inode); chain_pos = (ctx->pos - 2) & 0xffff; hash_pos = (ctx->pos - 2) >> 16; if (chain_pos == 0xffff) { affs_warning(sb, "readdir", "More than 65535 entries in chain"); chain_pos = 0; hash_pos++; ctx->pos = ((hash_pos << 16) | chain_pos) + 2; } dir_bh = affs_bread(sb, inode->i_ino); if (!dir_bh) goto out_unlock_dir; /* If the directory hasn't changed since the last call to readdir(), * we can jump directly to where we left off. */ ino = (u32)(long)file->private_data; if (ino && inode_eq_iversion(inode, file->f_version)) { pr_debug("readdir() left off=%d\n", ino); goto inside; } ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); for (i = 0; ino && i < chain_pos; i++) { fh_bh = affs_bread(sb, ino); if (!fh_bh) { affs_error(sb, "readdir","Cannot read block %d", i); error = -EIO; goto out_brelse_dir; } ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); affs_brelse(fh_bh); fh_bh = NULL; } if (ino) goto inside; hash_pos++; for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) { ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); if (!ino) continue; ctx->pos = (hash_pos << 16) + 2; inside: do { fh_bh = affs_bread(sb, ino); if (!fh_bh) { affs_error(sb, "readdir", "Cannot read block %d", ino); break; } namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)AFFSNAMEMAX); name = AFFS_TAIL(sb, fh_bh)->name + 1; pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n", namelen, name, ino, hash_pos, ctx->pos); if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN)) goto done; ctx->pos++; ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); affs_brelse(fh_bh); fh_bh = NULL; } while (ino); } done: file->f_version = inode_query_iversion(inode); file->private_data = (void *)(long)ino; affs_brelse(fh_bh); out_brelse_dir: affs_brelse(dir_bh); out_unlock_dir: affs_unlock_dir(inode); return error; }