root/fs/hpfs/namei.c
// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/hpfs/namei.c
 *
 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
 *
 *  adding & removing files & directories
 */
#include <linux/sched.h>
#include "hpfs_fn.h"

static void hpfs_update_directory_times(struct inode *dir)
{
        time64_t t = local_to_gmt(dir->i_sb, local_get_seconds(dir->i_sb));
        if (t == inode_get_mtime_sec(dir) &&
            t == inode_get_ctime_sec(dir))
                return;
        inode_set_mtime_to_ts(dir, inode_set_ctime(dir, t, 0));
        hpfs_write_inode_nolock(dir);
}

static struct dentry *hpfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
                                 struct dentry *dentry, umode_t mode)
{
        const unsigned char *name = dentry->d_name.name;
        unsigned len = dentry->d_name.len;
        struct quad_buffer_head qbh0;
        struct buffer_head *bh;
        struct hpfs_dirent *de;
        struct fnode *fnode;
        struct dnode *dnode;
        struct inode *result;
        fnode_secno fno;
        dnode_secno dno;
        int r;
        struct hpfs_dirent dee;
        int err;
        if ((err = hpfs_chk_name(name, &len))) return ERR_PTR(err==-ENOENT ? -EINVAL : err);
        hpfs_lock(dir->i_sb);
        err = -ENOSPC;
        fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
        if (!fnode)
                goto bail;
        dnode = hpfs_alloc_dnode(dir->i_sb, fno, &dno, &qbh0);
        if (!dnode)
                goto bail1;
        memset(&dee, 0, sizeof dee);
        dee.directory = 1;
        if (!(mode & 0222)) dee.read_only = 1;
        /*dee.archive = 0;*/
        dee.hidden = name[0] == '.';
        dee.fnode = cpu_to_le32(fno);
        dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));
        result = new_inode(dir->i_sb);
        if (!result) {
                err = -ENOMEM;
                goto bail2;
        }
        hpfs_init_inode(result);
        result->i_ino = fno;
        hpfs_i(result)->i_parent_dir = dir->i_ino;
        hpfs_i(result)->i_dno = dno;
        inode_set_mtime_to_ts(result,
                              inode_set_atime_to_ts(result, inode_set_ctime(result, local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date)), 0)));
        hpfs_i(result)->i_ea_size = 0;
        result->i_mode |= S_IFDIR;
        result->i_op = &hpfs_dir_iops;
        result->i_fop = &hpfs_dir_ops;
        result->i_blocks = 4;
        result->i_size = 2048;
        set_nlink(result, 2);
        if (dee.read_only)
                result->i_mode &= ~0222;

        r = hpfs_add_dirent(dir, name, len, &dee);
        if (r == 1)
                goto bail3;
        if (r == -1) {
                err = -EEXIST;
                goto bail3;
        }
        fnode->len = len;
        memcpy(fnode->name, name, len > 15 ? 15 : len);
        fnode->up = cpu_to_le32(dir->i_ino);
        fnode->flags |= FNODE_dir;
        fnode->btree.n_free_nodes = 7;
        fnode->btree.n_used_nodes = 1;
        fnode->btree.first_free = cpu_to_le16(0x14);
        fnode->u.external[0].disk_secno = cpu_to_le32(dno);
        fnode->u.external[0].file_secno = cpu_to_le32(-1);
        dnode->root_dnode = 1;
        dnode->up = cpu_to_le32(fno);
        de = hpfs_add_de(dir->i_sb, dnode, "\001\001", 2, 0);
        de->creation_date = de->write_date = de->read_date = cpu_to_le32(local_get_seconds(dir->i_sb));
        if (!(mode & 0222)) de->read_only = 1;
        de->first = de->directory = 1;
        /*de->hidden = de->system = 0;*/
        de->fnode = cpu_to_le32(fno);
        mark_buffer_dirty(bh);
        brelse(bh);
        hpfs_mark_4buffers_dirty(&qbh0);
        hpfs_brelse4(&qbh0);
        inc_nlink(dir);
        insert_inode_hash(result);

        if (!uid_eq(result->i_uid, current_fsuid()) ||
            !gid_eq(result->i_gid, current_fsgid()) ||
            result->i_mode != (mode | S_IFDIR)) {
                result->i_uid = current_fsuid();
                result->i_gid = current_fsgid();
                result->i_mode = mode | S_IFDIR;
                hpfs_write_inode_nolock(result);
        }
        hpfs_update_directory_times(dir);
        d_instantiate(dentry, result);
        hpfs_unlock(dir->i_sb);
        return NULL;
bail3:
        iput(result);
bail2:
        hpfs_brelse4(&qbh0);
        hpfs_free_dnode(dir->i_sb, dno);
bail1:
        brelse(bh);
        hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
        hpfs_unlock(dir->i_sb);
        return ERR_PTR(err);
}

static int hpfs_create(struct mnt_idmap *idmap, struct inode *dir,
                       struct dentry *dentry, umode_t mode, bool excl)
{
        const unsigned char *name = dentry->d_name.name;
        unsigned len = dentry->d_name.len;
        struct inode *result = NULL;
        struct buffer_head *bh;
        struct fnode *fnode;
        fnode_secno fno;
        int r;
        struct hpfs_dirent dee;
        int err;
        if ((err = hpfs_chk_name(name, &len)))
                return err==-ENOENT ? -EINVAL : err;
        hpfs_lock(dir->i_sb);
        err = -ENOSPC;
        fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
        if (!fnode)
                goto bail;
        memset(&dee, 0, sizeof dee);
        if (!(mode & 0222)) dee.read_only = 1;
        dee.archive = 1;
        dee.hidden = name[0] == '.';
        dee.fnode = cpu_to_le32(fno);
        dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));

        result = new_inode(dir->i_sb);
        if (!result) {
                err = -ENOMEM;
                goto bail1;
        }
        hpfs_init_inode(result);
        result->i_ino = fno;
        result->i_mode |= S_IFREG;
        result->i_mode &= ~0111;
        result->i_op = &hpfs_file_iops;
        result->i_fop = &hpfs_file_ops;
        set_nlink(result, 1);
        hpfs_i(result)->i_parent_dir = dir->i_ino;
        inode_set_mtime_to_ts(result,
                              inode_set_atime_to_ts(result, inode_set_ctime(result, local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date)), 0)));
        hpfs_i(result)->i_ea_size = 0;
        if (dee.read_only)
                result->i_mode &= ~0222;
        result->i_blocks = 1;
        result->i_size = 0;
        result->i_data.a_ops = &hpfs_aops;
        hpfs_i(result)->mmu_private = 0;

        r = hpfs_add_dirent(dir, name, len, &dee);
        if (r == 1)
                goto bail2;
        if (r == -1) {
                err = -EEXIST;
                goto bail2;
        }
        fnode->len = len;
        memcpy(fnode->name, name, len > 15 ? 15 : len);
        fnode->up = cpu_to_le32(dir->i_ino);
        mark_buffer_dirty(bh);
        brelse(bh);

        insert_inode_hash(result);

        if (!uid_eq(result->i_uid, current_fsuid()) ||
            !gid_eq(result->i_gid, current_fsgid()) ||
            result->i_mode != (mode | S_IFREG)) {
                result->i_uid = current_fsuid();
                result->i_gid = current_fsgid();
                result->i_mode = mode | S_IFREG;
                hpfs_write_inode_nolock(result);
        }
        hpfs_update_directory_times(dir);
        d_instantiate(dentry, result);
        hpfs_unlock(dir->i_sb);
        return 0;

bail2:
        iput(result);
bail1:
        brelse(bh);
        hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
        hpfs_unlock(dir->i_sb);
        return err;
}

static int hpfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
                      struct dentry *dentry, umode_t mode, dev_t rdev)
{
        const unsigned char *name = dentry->d_name.name;
        unsigned len = dentry->d_name.len;
        struct buffer_head *bh;
        struct fnode *fnode;
        fnode_secno fno;
        int r;
        struct hpfs_dirent dee;
        struct inode *result = NULL;
        int err;
        if ((err = hpfs_chk_name(name, &len))) return err==-ENOENT ? -EINVAL : err;
        if (hpfs_sb(dir->i_sb)->sb_eas < 2) return -EPERM;
        hpfs_lock(dir->i_sb);
        err = -ENOSPC;
        fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
        if (!fnode)
                goto bail;
        memset(&dee, 0, sizeof dee);
        if (!(mode & 0222)) dee.read_only = 1;
        dee.archive = 1;
        dee.hidden = name[0] == '.';
        dee.fnode = cpu_to_le32(fno);
        dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));

        result = new_inode(dir->i_sb);
        if (!result) {
                err = -ENOMEM;
                goto bail1;
        }
        hpfs_init_inode(result);
        result->i_ino = fno;
        hpfs_i(result)->i_parent_dir = dir->i_ino;
        inode_set_mtime_to_ts(result,
                              inode_set_atime_to_ts(result, inode_set_ctime(result, local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date)), 0)));
        hpfs_i(result)->i_ea_size = 0;
        result->i_uid = current_fsuid();
        result->i_gid = current_fsgid();
        set_nlink(result, 1);
        result->i_size = 0;
        result->i_blocks = 1;
        init_special_inode(result, mode, rdev);

        r = hpfs_add_dirent(dir, name, len, &dee);
        if (r == 1)
                goto bail2;
        if (r == -1) {
                err = -EEXIST;
                goto bail2;
        }
        fnode->len = len;
        memcpy(fnode->name, name, len > 15 ? 15 : len);
        fnode->up = cpu_to_le32(dir->i_ino);
        mark_buffer_dirty(bh);

        insert_inode_hash(result);

        hpfs_write_inode_nolock(result);
        hpfs_update_directory_times(dir);
        d_instantiate(dentry, result);
        brelse(bh);
        hpfs_unlock(dir->i_sb);
        return 0;
bail2:
        iput(result);
bail1:
        brelse(bh);
        hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
        hpfs_unlock(dir->i_sb);
        return err;
}

static int hpfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
                        struct dentry *dentry, const char *symlink)
{
        const unsigned char *name = dentry->d_name.name;
        unsigned len = dentry->d_name.len;
        struct buffer_head *bh;
        struct fnode *fnode;
        fnode_secno fno;
        int r;
        struct hpfs_dirent dee;
        struct inode *result;
        int err;
        if ((err = hpfs_chk_name(name, &len))) return err==-ENOENT ? -EINVAL : err;
        hpfs_lock(dir->i_sb);
        if (hpfs_sb(dir->i_sb)->sb_eas < 2) {
                hpfs_unlock(dir->i_sb);
                return -EPERM;
        }
        err = -ENOSPC;
        fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
        if (!fnode)
                goto bail;
        memset(&dee, 0, sizeof dee);
        dee.archive = 1;
        dee.hidden = name[0] == '.';
        dee.fnode = cpu_to_le32(fno);
        dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));

        result = new_inode(dir->i_sb);
        if (!result) {
                err = -ENOMEM;
                goto bail1;
        }
        result->i_ino = fno;
        hpfs_init_inode(result);
        hpfs_i(result)->i_parent_dir = dir->i_ino;
        inode_set_mtime_to_ts(result,
                              inode_set_atime_to_ts(result, inode_set_ctime(result, local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date)), 0)));
        hpfs_i(result)->i_ea_size = 0;
        result->i_mode = S_IFLNK | 0777;
        result->i_uid = current_fsuid();
        result->i_gid = current_fsgid();
        result->i_blocks = 1;
        set_nlink(result, 1);
        result->i_size = strlen(symlink);
        inode_nohighmem(result);
        result->i_op = &page_symlink_inode_operations;
        result->i_data.a_ops = &hpfs_symlink_aops;

        r = hpfs_add_dirent(dir, name, len, &dee);
        if (r == 1)
                goto bail2;
        if (r == -1) {
                err = -EEXIST;
                goto bail2;
        }
        fnode->len = len;
        memcpy(fnode->name, name, len > 15 ? 15 : len);
        fnode->up = cpu_to_le32(dir->i_ino);
        hpfs_set_ea(result, fnode, "SYMLINK", symlink, strlen(symlink));
        mark_buffer_dirty(bh);
        brelse(bh);

        insert_inode_hash(result);

        hpfs_write_inode_nolock(result);
        hpfs_update_directory_times(dir);
        d_instantiate(dentry, result);
        hpfs_unlock(dir->i_sb);
        return 0;
bail2:
        iput(result);
bail1:
        brelse(bh);
        hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
        hpfs_unlock(dir->i_sb);
        return err;
}

static int hpfs_unlink(struct inode *dir, struct dentry *dentry)
{
        const unsigned char *name = dentry->d_name.name;
        unsigned len = dentry->d_name.len;
        struct quad_buffer_head qbh;
        struct hpfs_dirent *de;
        struct inode *inode = d_inode(dentry);
        dnode_secno dno;
        int r;
        int err;

        hpfs_lock(dir->i_sb);
        hpfs_adjust_length(name, &len);

        err = -ENOENT;
        de = map_dirent(dir, hpfs_i(dir)->i_dno, name, len, &dno, &qbh);
        if (!de)
                goto out;

        err = -EPERM;
        if (de->first)
                goto out1;

        err = -EISDIR;
        if (de->directory)
                goto out1;

        r = hpfs_remove_dirent(dir, dno, de, &qbh, 1);
        switch (r) {
        case 1:
                hpfs_error(dir->i_sb, "there was error when removing dirent");
                err = -EFSERROR;
                break;
        case 2:         /* no space for deleting */
                err = -ENOSPC;
                break;
        default:
                drop_nlink(inode);
                err = 0;
        }
        goto out;

out1:
        hpfs_brelse4(&qbh);
out:
        if (!err)
                hpfs_update_directory_times(dir);
        hpfs_unlock(dir->i_sb);
        return err;
}

static int hpfs_rmdir(struct inode *dir, struct dentry *dentry)
{
        const unsigned char *name = dentry->d_name.name;
        unsigned len = dentry->d_name.len;
        struct quad_buffer_head qbh;
        struct hpfs_dirent *de;
        struct inode *inode = d_inode(dentry);
        dnode_secno dno;
        int n_items = 0;
        int err;
        int r;

        hpfs_adjust_length(name, &len);
        hpfs_lock(dir->i_sb);
        err = -ENOENT;
        de = map_dirent(dir, hpfs_i(dir)->i_dno, name, len, &dno, &qbh);
        if (!de)
                goto out;

        err = -EPERM;
        if (de->first)
                goto out1;

        err = -ENOTDIR;
        if (!de->directory)
                goto out1;

        hpfs_count_dnodes(dir->i_sb, hpfs_i(inode)->i_dno, NULL, NULL, &n_items);
        err = -ENOTEMPTY;
        if (n_items)
                goto out1;

        r = hpfs_remove_dirent(dir, dno, de, &qbh, 1);
        switch (r) {
        case 1:
                hpfs_error(dir->i_sb, "there was error when removing dirent");
                err = -EFSERROR;
                break;
        case 2:
                err = -ENOSPC;
                break;
        default:
                drop_nlink(dir);
                clear_nlink(inode);
                err = 0;
        }
        goto out;
out1:
        hpfs_brelse4(&qbh);
out:
        if (!err)
                hpfs_update_directory_times(dir);
        hpfs_unlock(dir->i_sb);
        return err;
}

static int hpfs_symlink_read_folio(struct file *file, struct folio *folio)
{
        char *link = folio_address(folio);
        struct inode *i = folio->mapping->host;
        struct fnode *fnode;
        struct buffer_head *bh;
        int err;

        err = -EIO;
        hpfs_lock(i->i_sb);
        if (!(fnode = hpfs_map_fnode(i->i_sb, i->i_ino, &bh)))
                goto fail;
        err = hpfs_read_ea(i->i_sb, fnode, "SYMLINK", link, PAGE_SIZE);
        brelse(bh);
fail:
        hpfs_unlock(i->i_sb);
        folio_end_read(folio, err == 0);
        return err;
}

const struct address_space_operations hpfs_symlink_aops = {
        .read_folio     = hpfs_symlink_read_folio
};

static int hpfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
                       struct dentry *old_dentry, struct inode *new_dir,
                       struct dentry *new_dentry, unsigned int flags)
{
        const unsigned char *old_name = old_dentry->d_name.name;
        unsigned old_len = old_dentry->d_name.len;
        const unsigned char *new_name = new_dentry->d_name.name;
        unsigned new_len = new_dentry->d_name.len;
        struct inode *i = d_inode(old_dentry);
        struct inode *new_inode = d_inode(new_dentry);
        struct quad_buffer_head qbh, qbh1;
        struct hpfs_dirent *dep, *nde;
        struct hpfs_dirent de;
        dnode_secno dno;
        int r;
        struct buffer_head *bh;
        struct fnode *fnode;
        int err;

        if (flags & ~RENAME_NOREPLACE)
                return -EINVAL;

        if ((err = hpfs_chk_name(new_name, &new_len))) return err;
        err = 0;
        hpfs_adjust_length(old_name, &old_len);

        hpfs_lock(i->i_sb);
        /* order doesn't matter, due to VFS exclusion */
        
        /* Erm? Moving over the empty non-busy directory is perfectly legal */
        if (new_inode && S_ISDIR(new_inode->i_mode)) {
                err = -EINVAL;
                goto end1;
        }

        if (!(dep = map_dirent(old_dir, hpfs_i(old_dir)->i_dno, old_name, old_len, &dno, &qbh))) {
                hpfs_error(i->i_sb, "lookup succeeded but map dirent failed");
                err = -ENOENT;
                goto end1;
        }
        copy_de(&de, dep);
        de.hidden = new_name[0] == '.';

        if (new_inode) {
                int r;
                if ((r = hpfs_remove_dirent(old_dir, dno, dep, &qbh, 1)) != 2) {
                        if ((nde = map_dirent(new_dir, hpfs_i(new_dir)->i_dno, new_name, new_len, NULL, &qbh1))) {
                                clear_nlink(new_inode);
                                copy_de(nde, &de);
                                memcpy(nde->name, new_name, new_len);
                                hpfs_mark_4buffers_dirty(&qbh1);
                                hpfs_brelse4(&qbh1);
                                goto end;
                        }
                        hpfs_error(new_dir->i_sb, "hpfs_rename: could not find dirent");
                        err = -EFSERROR;
                        goto end1;
                }
                err = -ENOSPC;
                goto end1;
        }

        if (new_dir == old_dir) hpfs_brelse4(&qbh);

        if ((r = hpfs_add_dirent(new_dir, new_name, new_len, &de))) {
                if (r == -1) hpfs_error(new_dir->i_sb, "hpfs_rename: dirent already exists!");
                err = r == 1 ? -ENOSPC : -EFSERROR;
                if (new_dir != old_dir) hpfs_brelse4(&qbh);
                goto end1;
        }
        
        if (new_dir == old_dir)
                if (!(dep = map_dirent(old_dir, hpfs_i(old_dir)->i_dno, old_name, old_len, &dno, &qbh))) {
                        hpfs_error(i->i_sb, "lookup succeeded but map dirent failed at #2");
                        err = -ENOENT;
                        goto end1;
                }

        if ((r = hpfs_remove_dirent(old_dir, dno, dep, &qbh, 0))) {
                hpfs_error(i->i_sb, "hpfs_rename: could not remove dirent");
                err = r == 2 ? -ENOSPC : -EFSERROR;
                goto end1;
        }

end:
        hpfs_i(i)->i_parent_dir = new_dir->i_ino;
        if (S_ISDIR(i->i_mode)) {
                inc_nlink(new_dir);
                drop_nlink(old_dir);
        }
        if ((fnode = hpfs_map_fnode(i->i_sb, i->i_ino, &bh))) {
                fnode->up = cpu_to_le32(new_dir->i_ino);
                fnode->len = new_len;
                memcpy(fnode->name, new_name, new_len>15?15:new_len);
                if (new_len < 15) memset(&fnode->name[new_len], 0, 15 - new_len);
                mark_buffer_dirty(bh);
                brelse(bh);
        }
end1:
        if (!err) {
                hpfs_update_directory_times(old_dir);
                hpfs_update_directory_times(new_dir);
        }
        hpfs_unlock(i->i_sb);
        return err;
}

const struct inode_operations hpfs_dir_iops =
{
        .create         = hpfs_create,
        .lookup         = hpfs_lookup,
        .unlink         = hpfs_unlink,
        .symlink        = hpfs_symlink,
        .mkdir          = hpfs_mkdir,
        .rmdir          = hpfs_rmdir,
        .mknod          = hpfs_mknod,
        .rename         = hpfs_rename,
        .setattr        = hpfs_setattr,
};