root/fs/affs/dir.c

DEFINITIONS

1. affs_readdir

/*
 *  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 "affs.h"

static int affs_readdir(struct file *, void *, filldir_t);

const struct file_operations affs_dir_operations = {
        .read           = generic_read_dir,
        .llseek         = generic_file_llseek,
        .readdir        = affs_readdir,
        .fsync          = 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_rename,
        .setattr        = affs_notify_change,
};

static int
affs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
        struct inode            *inode = filp->f_path.dentry->d_inode;
        struct super_block      *sb = inode->i_sb;
        struct buffer_head      *dir_bh;
        struct buffer_head      *fh_bh;
        unsigned char           *name;
        int                      namelen;
        u32                      i;
        int                      hash_pos;
        int                      chain_pos;
        u32                      f_pos;
        u32                      ino;
        int                      stored;
        int                      res;

        pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)filp->f_pos);

        stored = 0;
        res    = -EIO;
        dir_bh = NULL;
        fh_bh  = NULL;
        f_pos  = filp->f_pos;

        if (f_pos == 0) {
                filp->private_data = (void *)0;
                if (filldir(dirent, ".", 1, f_pos, inode->i_ino, DT_DIR) < 0)
                        return 0;
                filp->f_pos = f_pos = 1;
                stored++;
        }
        if (f_pos == 1) {
                if (filldir(dirent, "..", 2, f_pos, parent_ino(filp->f_path.dentry), DT_DIR) < 0)
                        return stored;
                filp->f_pos = f_pos = 2;
                stored++;
        }

        affs_lock_dir(inode);
        chain_pos = (f_pos - 2) & 0xffff;
        hash_pos  = (f_pos - 2) >> 16;
        if (chain_pos == 0xffff) {
                affs_warning(sb, "readdir", "More than 65535 entries in chain");
                chain_pos = 0;
                hash_pos++;
                filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
        }
        dir_bh = affs_bread(sb, inode->i_ino);
        if (!dir_bh)
                goto readdir_out;

        /* If the directory hasn't changed since the last call to readdir(),
         * we can jump directly to where we left off.
         */
        ino = (u32)(long)filp->private_data;
        if (ino && filp->f_version == inode->i_version) {
                pr_debug("AFFS: 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);
                        goto readdir_out;
                }
                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;
                f_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);
                                goto readdir_done;
                        }

                        namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
                        name = AFFS_TAIL(sb, fh_bh)->name + 1;
                        pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
                                 namelen, name, ino, hash_pos, f_pos);
                        if (filldir(dirent, name, namelen, f_pos, ino, DT_UNKNOWN) < 0)
                                goto readdir_done;
                        stored++;
                        f_pos++;
                        ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
                        affs_brelse(fh_bh);
                        fh_bh = NULL;
                } while (ino);
        }
readdir_done:
        filp->f_pos = f_pos;
        filp->f_version = inode->i_version;
        filp->private_data = (void *)(long)ino;
        res = stored;

readdir_out:
        affs_brelse(dir_bh);
        affs_brelse(fh_bh);
        affs_unlock_dir(inode);
        pr_debug("AFFS: readdir()=%d\n", stored);
        return res;
}