C++ d_inode函数代码示例

/*
 * hfs_remove()
 *
 * This serves as both unlink() and rmdir() in the inode_operations
 * structure for regular HFS directories.  The purpose is to delete
 * an existing child, given the inode for the parent directory and
 * the name (and its length) of the existing directory.
 *
 * HFS does not have hardlinks, so both rmdir and unlink set the
 * link count to 0.  The only difference is the emptiness check.
 */
static int hfs_remove(struct inode *dir, struct dentry *dentry)
{
	struct inode *inode = d_inode(dentry);
	int res;

	if (S_ISDIR(inode->i_mode) && inode->i_size != 2)
		return -ENOTEMPTY;
	res = hfs_cat_delete(inode->i_ino, dir, &dentry->d_name);
	if (res)
		return res;
	clear_nlink(inode);
	inode->i_ctime = current_time(inode);
	hfs_delete_inode(inode);
	mark_inode_dirty(inode);
	return 0;
}

static struct dentry *jffs2_get_parent(struct dentry *child)
{
	struct jffs2_inode_info *f;
	uint32_t pino;

	BUG_ON(!d_is_dir(child));

	f = JFFS2_INODE_INFO(d_inode(child));

	pino = f->inocache->pino_nlink;

	JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
		    f->inocache->ino, pino);

	return d_obtain_alias(jffs2_iget(child->d_sb, pino));
}

static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
		const void *value, size_t size, int flags, int type)
{
	struct inode *inode = d_inode(dentry);

	if (strcmp(name, "") != 0)
		return -EINVAL;
	if (!inode_owner_or_capable(inode))
		return -EPERM;
	if (value == NULL)
		return -EINVAL;

	F2FS_I(inode)->i_advise |= *(char *)value;
	mark_inode_dirty(inode);
	return 0;
}

static int do_open_dir(struct file *file, int flags, struct file *h_file)
{
	int err;
	aufs_bindex_t bindex, btail;
	struct dentry *dentry, *h_dentry;
	struct vfsmount *mnt;

	FiMustWriteLock(file);
	AuDebugOn(h_file);

	err = 0;
	mnt = file->f_path.mnt;
	dentry = file->f_path.dentry;
	file->f_version = d_inode(dentry)->i_version;
	bindex = au_dbtop(dentry);
	au_set_fbtop(file, bindex);
	btail = au_dbtaildir(dentry);
	au_set_fbbot_dir(file, btail);
	for (; !err && bindex <= btail; bindex++) {
		h_dentry = au_h_dptr(dentry, bindex);
		if (!h_dentry)
			continue;

		err = vfsub_test_mntns(mnt, h_dentry->d_sb);
		if (unlikely(err))
			break;
		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
		if (IS_ERR(h_file)) {
			err = PTR_ERR(h_file);
			break;
		}
		au_set_h_fptr(file, bindex, h_file);
	}
	au_update_figen(file);
	/* todo: necessary? */
	/* file->f_ra = h_file->f_ra; */
	if (!err)
		return 0; /* success */

	/* close all */
	for (bindex = au_fbtop(file); bindex <= btail; bindex++)
		au_set_h_fptr(file, bindex, NULL);
	au_set_fbtop(file, -1);
	au_set_fbbot_dir(file, -1);

	return err;
}

int
xfs_readlink_by_handle(
	struct file		*parfilp,
	xfs_fsop_handlereq_t	*hreq)
{
	struct dentry		*dentry;
	__u32			olen;
	void			*link;
	int			error;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	dentry = xfs_handlereq_to_dentry(parfilp, hreq);
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);

	/* Restrict this handle operation to symlinks only. */
	if (!d_is_symlink(dentry)) {
		error = -EINVAL;
		goto out_dput;
	}

	if (copy_from_user(&olen, hreq->ohandlen, sizeof(__u32))) {
		error = -EFAULT;
		goto out_dput;
	}

	link = kmalloc(MAXPATHLEN+1, GFP_KERNEL);
	if (!link) {
		error = -ENOMEM;
		goto out_dput;
	}

	error = xfs_readlink(XFS_I(d_inode(dentry)), link);
	if (error)
		goto out_kfree;
	error = readlink_copy(hreq->ohandle, olen, link);
	if (error)
		goto out_kfree;

 out_kfree:
	kfree(link);
 out_dput:
	dput(dentry);
	return error;
}

/*
 * Cross-directory rename, target does not exist.  Just a little nasty.
 * Create a new dentry in the target dir, then remove the old dentry,
 * all the while taking care to remember our operation in the journal.
 */
static int logfs_rename_cross(struct inode *old_dir, struct dentry *old_dentry,
			      struct inode *new_dir, struct dentry *new_dentry)
{
	struct logfs_super *super = logfs_super(old_dir->i_sb);
	struct logfs_disk_dentry dd;
	struct logfs_transaction *ta;
	loff_t pos;
	int err;

	/* 1. locate source dd */
	err = logfs_get_dd(old_dir, old_dentry, &dd, &pos);
	if (err)
		return err;

	ta = kzalloc(sizeof(*ta), GFP_KERNEL);
	if (!ta)
		return -ENOMEM;

	ta->state = CROSS_RENAME_1;
	ta->dir = old_dir->i_ino;
	ta->pos = pos;

	/* 2. write target dd */
	mutex_lock(&super->s_dirop_mutex);
	logfs_add_transaction(new_dir, ta);
	err = logfs_write_dir(new_dir, new_dentry, d_inode(old_dentry));
	if (!err)
		err = write_inode(new_dir);

	if (err) {
		super->s_rename_dir = 0;
		super->s_rename_pos = 0;
		abort_transaction(new_dir, ta);
		goto out;
	}

	/* 3. remove source dd */
	ta->state = CROSS_RENAME_2;
	logfs_add_transaction(old_dir, ta);
	err = logfs_delete_dd(old_dir, pos);
	if (!err)
		err = write_inode(old_dir);
	LOGFS_BUG_ON(err, old_dir->i_sb);
out:
	mutex_unlock(&super->s_dirop_mutex);
	return err;
}

static int ceph_get_name(struct dentry *parent, char *name,
			 struct dentry *child)
{
	struct ceph_mds_client *mdsc;
	struct ceph_mds_request *req;
	int err;

	mdsc = ceph_inode_to_client(d_inode(child))->mdsc;
	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
				       USE_ANY_MDS);
	if (IS_ERR(req))
		return PTR_ERR(req);

	inode_lock(d_inode(parent));

	req->r_inode = d_inode(child);
	ihold(d_inode(child));
	req->r_ino2 = ceph_vino(d_inode(parent));
	req->r_parent = d_inode(parent);
	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
	req->r_num_caps = 2;
	err = ceph_mdsc_do_request(mdsc, NULL, req);

	inode_unlock(d_inode(parent));

	if (!err) {
		struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
		memcpy(name, rinfo->dname, rinfo->dname_len);
		name[rinfo->dname_len] = 0;
		dout("get_name %p ino %llx.%llx name %s\n",
		     child, ceph_vinop(d_inode(child)), name);
	} else {
		dout("get_name %p ino %llx.%llx err %d\n",
		     child, ceph_vinop(d_inode(child)), err);
	}

	ceph_mdsc_put_request(req);
	return err;
}

/*
 * Validate dentries for encrypted directories to make sure we aren't
 * potentially caching stale data after a key has been added or
 * removed.
 */
static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags)
{
	struct inode *dir = d_inode(dentry->d_parent);
	struct ext4_crypt_info *ci = EXT4_I(dir)->i_crypt_info;
	int dir_has_key, cached_with_key;

	if (!ext4_encrypted_inode(dir))
		return 0;

	if (ci && ci->ci_keyring_key &&
	    (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
					  (1 << KEY_FLAG_REVOKED) |
					  (1 << KEY_FLAG_DEAD))))
		ci = NULL;

	/* this should eventually be an flag in d_flags */
	cached_with_key = dentry->d_fsdata != NULL;
	dir_has_key = (ci != NULL);

	/*
	 * If the dentry was cached without the key, and it is a
	 * negative dentry, it might be a valid name.  We can't check
	 * if the key has since been made available due to locking
	 * reasons, so we fail the validation so ext4_lookup() can do
	 * this check.
	 *
	 * We also fail the validation if the dentry was created with
	 * the key present, but we no longer have the key, or vice versa.
	 */
	if ((!cached_with_key && d_is_negative(dentry)) ||
	    (!cached_with_key && dir_has_key) ||
	    (cached_with_key && !dir_has_key)) {
#if 0				/* Revalidation debug */
		char buf[80];
		char *cp = simple_dname(dentry, buf, sizeof(buf));

		if (IS_ERR(cp))
			cp = (char *) "???";
		pr_err("revalidate: %s %p %d %d %d\n", cp, dentry->d_fsdata,
		       cached_with_key, d_is_negative(dentry),
		       dir_has_key);
#endif
		return 0;
	}
	return 1;
}

/*
 * read the attributes of an inode
 */
int afs_getattr(const struct path *path, struct kstat *stat,
		u32 request_mask, unsigned int query_flags)
{
	struct inode *inode = d_inode(path->dentry);
	struct afs_vnode *vnode = AFS_FS_I(inode);
	int seq = 0;

	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);

	do {
		read_seqbegin_or_lock(&vnode->cb_lock, &seq);
		generic_fillattr(inode, stat);
	} while (need_seqretry(&vnode->cb_lock, seq));

	done_seqretry(&vnode->cb_lock, seq);
	return 0;
}

static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
		struct kstat *stat)
{
	struct inode *inode = d_inode(dentry);
	struct net *net;

	net = get_proc_task_net(inode);

	generic_fillattr(inode, stat);

	if (net != NULL) {
		stat->nlink = net->proc_net->nlink;
		put_net(net);
	}

	return 0;
}

/*
 *	sysv_find_entry()
 *
 * finds an entry in the specified directory with the wanted name. It
 * returns the cache buffer in which the entry was found, and the entry
 * itself (as a parameter - res_dir). It does NOT read the inode of the
 * entry - you'll have to do that yourself if you want to.
 */
struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_page)
{
	const char * name = dentry->d_name.name;
	int namelen = dentry->d_name.len;
	struct inode * dir = d_inode(dentry->d_parent);
	unsigned long start, n;
	unsigned long npages = dir_pages(dir);
	struct page *page = NULL;
	struct sysv_dir_entry *de;

	*res_page = NULL;

	start = SYSV_I(dir)->i_dir_start_lookup;
	if (start >= npages)
		start = 0;
	n = start;

	do {
		char *kaddr;
		page = dir_get_page(dir, n);
		if (!IS_ERR(page)) {
			kaddr = (char*)page_address(page);
			de = (struct sysv_dir_entry *) kaddr;
			kaddr += PAGE_SIZE - SYSV_DIRSIZE;
			for ( ; (char *) de <= kaddr ; de++) {
				if (!de->inode)
					continue;
				if (namecompare(namelen, SYSV_NAMELEN,
							name, de->name))
					goto found;
			}
			dir_put_page(page);
		}

		if (++n >= npages)
			n = 0;
	} while (n != start);

	return NULL;

found:
	SYSV_I(dir)->i_dir_start_lookup = n;
	*res_page = page;
	return de;
}

ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
	struct inode *inode = d_inode(dentry);
	struct f2fs_xattr_entry *entry;
	void *base_addr;
	int error = 0;
	size_t rest = buffer_size;

	down_read(&F2FS_I(inode)->i_xattr_sem);
	error = read_all_xattrs(inode, NULL, &base_addr);
	up_read(&F2FS_I(inode)->i_xattr_sem);
	if (error)
		return error;

	list_for_each_xattr(entry, base_addr) {
		const struct xattr_handler *handler =
			f2fs_xattr_handler(entry->e_name_index);
		const char *prefix;
		size_t prefix_len;
		size_t size;

		if (!handler || (handler->list && !handler->list(dentry)))
			continue;

		prefix = handler->prefix ?: handler->name;
		prefix_len = strlen(prefix);
		size = prefix_len + entry->e_name_len + 1;
		if (buffer) {
			if (size > rest) {
				error = -ERANGE;
				goto cleanup;
			}
			memcpy(buffer, prefix, prefix_len);
			buffer += prefix_len;
			memcpy(buffer, entry->e_name, entry->e_name_len);
			buffer += entry->e_name_len;
			*buffer++ = 0;
		}
		rest -= size;
	}
	error = buffer_size - rest;
cleanup:
	kzfree(base_addr);
	return error;
}

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

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

	error = ufs_add_link(dentry, inode);
	if (error) {
		inode_dec_link_count(inode);
		iput(inode);
	} else
		d_instantiate(dentry, inode);
	return error;
}

/*
 * Encode post-operation attributes.
 * The inode may be NULL if the call failed because of a stale file
 * handle. In this case, no attributes are returned.
 */
static __be32 *
encode_post_op_attr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)
{
	struct dentry *dentry = fhp->fh_dentry;
	if (dentry && d_really_is_positive(dentry)) {
	        __be32 err;
		struct kstat stat;

		err = fh_getattr(fhp, &stat);
		if (!err) {
			*p++ = xdr_one;		/* attributes follow */
			lease_get_mtime(d_inode(dentry), &stat.mtime);
			return encode_fattr3(rqstp, p, fhp, &stat);
		}
	}
	*p++ = xdr_zero;
	return p;
}

static void au_do_hide(struct dentry *dentry)
{
	struct inode *inode;

	if (d_really_is_positive(dentry)) {
		inode = d_inode(dentry);
		if (!d_is_dir(dentry)) {
			if (inode->i_nlink && !d_unhashed(dentry))
				drop_nlink(inode);
		} else {
			clear_nlink(inode);
			/* stop next lookup */
			inode->i_flags |= S_DEAD;
		}
		smp_mb(); /* necessary? */
	}
	d_drop(dentry);
}