mirror of https://gitee.com/openkylin/linux.git
136 lines
3.3 KiB
C
136 lines
3.3 KiB
C
/*
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* linux/fs/affs/dir.c
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*
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* (c) 1996 Hans-Joachim Widmaier - Rewritten
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*
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* (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
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*
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* (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
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*
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* (C) 1991 Linus Torvalds - minix filesystem
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*
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* affs directory handling functions
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*
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*/
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#include "affs.h"
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static int affs_readdir(struct file *, struct dir_context *);
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const struct file_operations affs_dir_operations = {
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.read = generic_read_dir,
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.llseek = generic_file_llseek,
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.iterate = affs_readdir,
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.fsync = affs_file_fsync,
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};
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/*
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* directories can handle most operations...
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*/
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const struct inode_operations affs_dir_inode_operations = {
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.create = affs_create,
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.lookup = affs_lookup,
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.link = affs_link,
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.unlink = affs_unlink,
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.symlink = affs_symlink,
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.mkdir = affs_mkdir,
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.rmdir = affs_rmdir,
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.rename = affs_rename,
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.setattr = affs_notify_change,
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};
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static int
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affs_readdir(struct file *file, struct dir_context *ctx)
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{
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struct inode *inode = file_inode(file);
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struct super_block *sb = inode->i_sb;
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struct buffer_head *dir_bh = NULL;
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struct buffer_head *fh_bh = NULL;
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unsigned char *name;
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int namelen;
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u32 i;
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int hash_pos;
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int chain_pos;
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u32 ino;
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pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)ctx->pos);
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if (ctx->pos < 2) {
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file->private_data = (void *)0;
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if (!dir_emit_dots(file, ctx))
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return 0;
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}
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affs_lock_dir(inode);
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chain_pos = (ctx->pos - 2) & 0xffff;
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hash_pos = (ctx->pos - 2) >> 16;
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if (chain_pos == 0xffff) {
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affs_warning(sb, "readdir", "More than 65535 entries in chain");
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chain_pos = 0;
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hash_pos++;
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ctx->pos = ((hash_pos << 16) | chain_pos) + 2;
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}
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dir_bh = affs_bread(sb, inode->i_ino);
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if (!dir_bh)
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goto readdir_out;
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/* If the directory hasn't changed since the last call to readdir(),
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* we can jump directly to where we left off.
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*/
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ino = (u32)(long)file->private_data;
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if (ino && file->f_version == inode->i_version) {
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pr_debug("AFFS: readdir() left off=%d\n", ino);
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goto inside;
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}
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ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
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for (i = 0; ino && i < chain_pos; i++) {
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fh_bh = affs_bread(sb, ino);
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if (!fh_bh) {
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affs_error(sb, "readdir","Cannot read block %d", i);
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return -EIO;
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}
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ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
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affs_brelse(fh_bh);
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fh_bh = NULL;
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}
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if (ino)
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goto inside;
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hash_pos++;
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for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
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ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
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if (!ino)
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continue;
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ctx->pos = (hash_pos << 16) + 2;
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inside:
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do {
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fh_bh = affs_bread(sb, ino);
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if (!fh_bh) {
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affs_error(sb, "readdir","Cannot read block %d", ino);
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break;
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}
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namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
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name = AFFS_TAIL(sb, fh_bh)->name + 1;
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pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
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namelen, name, ino, hash_pos, (u32)ctx->pos);
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if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN))
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goto readdir_done;
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ctx->pos++;
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ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
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affs_brelse(fh_bh);
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fh_bh = NULL;
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} while (ino);
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}
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readdir_done:
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file->f_version = inode->i_version;
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file->private_data = (void *)(long)ino;
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readdir_out:
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affs_brelse(dir_bh);
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affs_brelse(fh_bh);
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affs_unlock_dir(inode);
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return 0;
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}
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