namei.c

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/*
 * linux/fs/ufs/namei.c
 *
 * Migration to usage of "page cache" on May 2006 by
 * Evgeniy Dushistov <[email protected]> based on ext2 code base.
 *
 * Copyright (C) 1998
 * Daniel Pirkl <[email protected]>
 * Charles University, Faculty of Mathematics and Physics
 *
 *  from
 *
 *  linux/fs/ext2/namei.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([email protected])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/namei.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller ([email protected]), 1995
 */

#include <linux/time.h>
#include <linux/fs.h>

#include "ufs_fs.h"
#include "ufs.h"
#include "util.h"

static inline int ufs_add_nondir(struct dentry *dentry, struct inode *inode)
{
    int err = ufs_add_link(dentry, inode);
    if (!err) {
        d_instantiate(dentry, inode);
        return 0;
    }
    inode_dec_link_count(inode);
    iput(inode);
    return err;
}

static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
{
    struct inode * inode = NULL;
    ino_t ino;
    
    if (dentry->d_name.len > UFS_MAXNAMLEN)
        return ERR_PTR(-ENAMETOOLONG);

    lock_ufs(dir->i_sb);
    ino = ufs_inode_by_name(dir, &dentry->d_name);
    if (ino)
        inode = ufs_iget(dir->i_sb, ino);
    unlock_ufs(dir->i_sb);
    return d_splice_alias(inode, dentry);
}

/*
 * By the time this is called, we already have created
 * the directory cache entry for the new file, but it
 * is so far negative - it has no inode.
 *
 * If the create succeeds, we fill in the inode information
 * with d_instantiate(). 
 */
static int ufs_create (struct inode * dir, struct dentry * dentry, umode_t mode,
        bool excl)
{
    struct inode *inode;
    int err;

    UFSD("BEGIN\n");

    inode = ufs_new_inode(dir, mode);
    err = PTR_ERR(inode);

    if (!IS_ERR(inode)) {
        inode->i_op = &ufs_file_inode_operations;
        inode->i_fop = &ufs_file_operations;
        inode->i_mapping->a_ops = &ufs_aops;
        mark_inode_dirty(inode);
        lock_ufs(dir->i_sb);
        err = ufs_add_nondir(dentry, inode);
        unlock_ufs(dir->i_sb);
    }
    UFSD("END: err=%d\n", err);
    return err;
}

static int ufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
{
    struct inode *inode;
    int err;

    if (!old_valid_dev(rdev))
        return -EINVAL;

    inode = ufs_new_inode(dir, mode);
    err = PTR_ERR(inode);
    if (!IS_ERR(inode)) {
        init_special_inode(inode, mode, rdev);
        ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
        mark_inode_dirty(inode);
        lock_ufs(dir->i_sb);
        err = ufs_add_nondir(dentry, inode);
        unlock_ufs(dir->i_sb);
    }
    return err;
}

static int ufs_symlink (struct inode * dir, struct dentry * dentry,
    const char * symname)
{
    struct super_block * sb = dir->i_sb;
    int err = -ENAMETOOLONG;
    unsigned l = strlen(symname)+1;
    struct inode * inode;

    if (l > sb->s_blocksize)
        goto out_notlocked;

    lock_ufs(dir->i_sb);
    inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
    err = PTR_ERR(inode);
    if (IS_ERR(inode))
        goto out;

    if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
        /* slow symlink */
        inode->i_op = &ufs_symlink_inode_operations;
        inode->i_mapping->a_ops = &ufs_aops;
        err = page_symlink(inode, symname, l);
        if (err)
            goto out_fail;
    } else {
        /* fast symlink */
        inode->i_op = &ufs_fast_symlink_inode_operations;
        memcpy(UFS_I(inode)->i_u1.i_symlink, symname, l);
        inode->i_size = l-1;
    }
    mark_inode_dirty(inode);

    err = ufs_add_nondir(dentry, inode);
out:
    unlock_ufs(dir->i_sb);
out_notlocked:
    return err;

out_fail:
    inode_dec_link_count(inode);
    iput(inode);
    goto out;
}

static int ufs_link (struct dentry * old_dentry, struct inode * dir,
    struct dentry *dentry)
{
    struct inode *inode = old_dentry->d_inode;
    int error;

    lock_ufs(dir->i_sb);

    inode->i_ctime = CURRENT_TIME_SEC;
    inode_inc_link_count(inode);
    ihold(inode);

    error = ufs_add_nondir(dentry, inode);
    unlock_ufs(dir->i_sb);
    return error;
}

static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
{
    struct inode * inode;
    int err;

    lock_ufs(dir->i_sb);
    inode_inc_link_count(dir);

    inode = ufs_new_inode(dir, S_IFDIR|mode);
    err = PTR_ERR(inode);
    if (IS_ERR(inode))
        goto out_dir;

    inode->i_op = &ufs_dir_inode_operations;
    inode->i_fop = &ufs_dir_operations;
    inode->i_mapping->a_ops = &ufs_aops;

    inode_inc_link_count(inode);

    err = ufs_make_empty(inode, dir);
    if (err)
        goto out_fail;

    err = ufs_add_link(dentry, inode);
    if (err)
        goto out_fail;
    unlock_ufs(dir->i_sb);

    d_instantiate(dentry, inode);
out:
    return err;

out_fail:
    inode_dec_link_count(inode);
    inode_dec_link_count(inode);
    iput (inode);
out_dir:
    inode_dec_link_count(dir);
    unlock_ufs(dir->i_sb);
    goto out;
}

static int ufs_unlink(struct inode *dir, struct dentry *dentry)
{
    struct inode * inode = dentry->d_inode;
    struct ufs_dir_entry *de;
    struct page *page;
    int err = -ENOENT;

    de = ufs_find_entry(dir, &dentry->d_name, &page);
    if (!de)
        goto out;

    err = ufs_delete_entry(dir, de, page);
    if (err)
        goto out;

    inode->i_ctime = dir->i_ctime;
    inode_dec_link_count(inode);
    err = 0;
out:
    return err;
}

static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
{
    struct inode * inode = dentry->d_inode;
    int err= -ENOTEMPTY;

    lock_ufs(dir->i_sb);
    if (ufs_empty_dir (inode)) {
        err = ufs_unlink(dir, dentry);
        if (!err) {
            inode->i_size = 0;
            inode_dec_link_count(inode);
            inode_dec_link_count(dir);
        }
    }
    unlock_ufs(dir->i_sb);
    return err;
}

static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
              struct inode *new_dir, struct dentry *new_dentry)
{
    struct inode *old_inode = old_dentry->d_inode;
    struct inode *new_inode = new_dentry->d_inode;
    struct page *dir_page = NULL;
    struct ufs_dir_entry * dir_de = NULL;
    struct page *old_page;
    struct ufs_dir_entry *old_de;
    int err = -ENOENT;

    old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
    if (!old_de)
        goto out;

    if (S_ISDIR(old_inode->i_mode)) {
        err = -EIO;
        dir_de = ufs_dotdot(old_inode, &dir_page);
        if (!dir_de)
            goto out_old;
    }

    if (new_inode) {
        struct page *new_page;
        struct ufs_dir_entry *new_de;

        err = -ENOTEMPTY;
        if (dir_de && !ufs_empty_dir(new_inode))
            goto out_dir;

        err = -ENOENT;
        new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
        if (!new_de)
            goto out_dir;
        ufs_set_link(new_dir, new_de, new_page, old_inode);
        new_inode->i_ctime = CURRENT_TIME_SEC;
        if (dir_de)
            drop_nlink(new_inode);
        inode_dec_link_count(new_inode);
    } else {
        err = ufs_add_link(new_dentry, old_inode);
        if (err)
            goto out_dir;
        if (dir_de)
            inode_inc_link_count(new_dir);
    }

    /*
     * Like most other Unix systems, set the ctime for inodes on a
     * rename.
     */
    old_inode->i_ctime = CURRENT_TIME_SEC;

    ufs_delete_entry(old_dir, old_de, old_page);
    mark_inode_dirty(old_inode);

    if (dir_de) {
        ufs_set_link(old_inode, dir_de, dir_page, new_dir);
        inode_dec_link_count(old_dir);
    }
    return 0;


out_dir:
    if (dir_de) {
        kunmap(dir_page);
        page_cache_release(dir_page);
    }
out_old:
    kunmap(old_page);
    page_cache_release(old_page);
out:
    return err;
}

const struct inode_operations ufs_dir_inode_operations = {
    .create     = ufs_create,
    .lookup     = ufs_lookup,
    .link       = ufs_link,
    .unlink     = ufs_unlink,
    .symlink    = ufs_symlink,
    .mkdir      = ufs_mkdir,
    .rmdir      = ufs_rmdir,
    .mknod      = ufs_mknod,
    .rename     = ufs_rename,
};