fs_incore.c

非常经典的一个分布式系统

		if (((l == LONG_MIN || l == LONG_MAX) &&
		     errno == ERANGE) ||
		    (long )gid != l)
			return -EINVAL;
		if (*cp != '\0')
			return -EINVAL;
	}

	err = 0;

	dev = _sysio_dev_alloc();

	mnt = NULL;
	rootpb = NULL;
	rooti = NULL;
	fs = NULL;
	icino = NULL;
	icfs = NULL;

	/*
	 * Create new FS.
	 */
	icfs = malloc(sizeof(struct incore_filesys));
	if (!icfs) {
		err = -ENOMEM;
		goto error;
	}
	(void )memset(icfs, 0, sizeof(struct incore_filesys));
	LIST_INIT(&icfs->icfs_icinodes);

	/*
	 * Create root i-node.
	 */
	(void )memset(&stat, 0, sizeof(stat));
	stat.st_dev = dev;
	inum = incore_inum_alloc();
#ifdef HAVE__ST_INO
	stat.__st_ino = inum; 
#endif
	stat.st_mode = S_IFDIR | (mode & 07777);
	stat.st_nlink = 2;
	stat.st_uid = uid;
	stat.st_gid = gid;
	stat.st_size = 0;
	stat.st_blksize = INCORE_BLKSIZE;
	stat.st_blocks = 0;
	stat.st_ctime = stat.st_mtime = stat.st_atime = 0;
	stat.st_ino = inum;
	icino = incore_directory_new(icfs, NULL, &stat);
	if (!icino)
		return -ENOSPC;
	icino->ici_st.st_atime = icino->ici_st.st_mtime;

	fs =
	    _sysio_fs_new(&incore_fs_ops,
			  (flags & MOUNT_F_RO) ? FS_F_RO : 0,
			  icfs);
	if (!fs) {
		err = -ENOMEM;
		goto error;
	}

	/*
	 * Create root for system.
	 *
	 * Persistent across remounts because we ask for immunity.
	 */
	rooti =
	    _sysio_i_new(fs,
			 &icino->ici_fileid,
			 &icino->ici_st,
			 1,
			 &_sysio_incore_dir_ops,
			 icino);
	if (!rooti) {
		err = -ENOMEM;
		goto error;
	}
	rootpb = _sysio_pb_new(&noname, NULL, rooti);
	if (!rootpb) {
		err = -ENOMEM;
		goto error;
	}

	/*
	 * Have path-node specified by the given source argument. Let the
	 * system finish the job, now.
	 */
	mnt = NULL;
	err =
	    _sysio_do_mount(fs,
			    rootpb,
			    flags,
			    tocover,
			    &mnt);
	if (err)
		goto error;

	*mntp = mnt;

	goto out;

error:
	if (mnt && _sysio_do_unmount(mnt) != 0)
			abort();
	if (rootpb) {
		_sysio_pb_gone(rootpb);
		rooti = NULL;
	}
	if (rooti)
		I_RELE(rooti);
	if (fs) {
		FS_RELE(fs);
		goto out;
	}
	if (icino) {
		incore_i_destroy(icino);
		goto out;
	}
	if (icfs) {
		free(icfs);
		goto out;
	}

out:
	return err;
}

static void
_sysio_incore_fsop_gone(struct filesys *fs)
{
	struct incore_filesys *icfs;
	struct incore_inode *icino, *oicino;

	icfs = FS2ICFS(fs);

	/*
	 * Free up i-node resource associated with this file system.
	 */
	icino = icfs->icfs_icinodes.lh_first;
	while (icino) {
		oicino = icino;
		icino = icino->ici_link.le_next;
		incore_i_destroy(oicino);
	}

	/*
	 * Free the FS record.
	 */
	free(icfs);
}

/*
 * A directory search engine. Various functions are carried out by
 * supplying appropriate callback functions.
 *
 * The two arguments, entry and hole, are called, if not null, for each
 * directory entry and hole, respectively.
 */
static void *
incore_directory_probe(void *data,
		       size_t siz,
		       _SYSIO_OFF_T origin
#ifndef _DIRENT_HAVE_D_OFF
				__IS_UNUSED
#endif
		       ,
		       probe_ty entry,
		       probe_ty hole,
		       void *arg)
{
	struct intnl_dirent *de;
	void	*p;
	size_t	n;

	de = data;
	for (;;) {
#ifdef _DIRENT_HAVE_D_OFF
		assert(de->d_off);
#else
		assert(de->d_reclen);
#endif
		if (entry && (p = (*entry)(de, de->d_reclen, arg)))
			return p;
		n =
#ifdef _DIRENT_HAVE_D_OFF
		    de->d_off - origin;
#else
		    ((void *)de - data) + de->d_reclen;
#endif
		if (hole) {
			p = (*hole)((void *)de, de->d_reclen, arg);
			if (p)
				return p;
		}
		if (n >= siz)
			break;
		de = (struct intnl_dirent *)((char *)data + n);
	}

	return NULL;
}

static struct intnl_dirent *
incore_directory_match(struct intnl_dirent *de,
		       size_t reclen,
		       struct lookup_data *ld)
{
	size_t	len;

#if defined(BSD) || defined(REDSTORM)
	if (IFTODT(de->d_type) == DT_WHT)
		return NULL;
#endif
#ifdef _DIRENT_HAVE_D_NAMLEN
	len = de->d_namlen;
#else
	{
		const char *cp, *end;

		cp = de->d_name;
		end = (const char *)de + reclen;
		while (cp < end && *cp != '\0')
			cp++;
		len = cp - de->d_name;
	}
#endif
	if (ld->name->len == len &&
	    strncmp(de->d_name, ld->name->name, ld->name->len) == 0)
		return de;
	ld->de = de;
	return NULL;
}

static int
_sysio_incore_dirop_lookup(struct pnode *pno,
			   struct inode **inop,
			   struct intent *intnt __IS_UNUSED,
			   const char *path __IS_UNUSED)
{
	struct inode *ino;
	struct intnl_dirent *de;
	struct incore_inode *icino;
	struct lookup_data lookup_data;
	struct file_identifier fileid;
#ifdef notdef
	struct inode_ops *ops;
#endif

	/*
	 * Revalidate?
	 */
	if (*inop) {
		icino = I2IC(*inop);
		assert(icino);
		(*inop)->i_stbuf = icino->ici_st;
		return 0;
	}

	ino = pno->p_parent->p_base->pb_ino;
	icino = I2IC(ino);
	INCORE_LD_INIT(&lookup_data,
		       ULONG_MAX,
		       &pno->p_base->pb_name);
	de =
	    incore_directory_probe(icino->ici_data,
				   icino->ici_st.st_size,
				   0,
				   (probe_ty )incore_directory_match,
				   NULL,
				   &lookup_data);
	if (!de)
		return -ENOENT;

	fileid.fid_data = &de->d_ino;
	fileid.fid_len = sizeof(de->d_ino);
	ino =
	    _sysio_i_find(ino->i_fs, &fileid);
#ifdef notdef
	if (ino)
		goto out;
	icino->ici_fileid.fid_data = &icino->ici_st.st_ino;
	icino->ici_fileid.fid_len = sizeof(icino->ici_st.st_ino);
	ops = NULL;
	switch (icino->ici_st.st_mode & S_IFMT) {
	case S_IFDIR:
		ops = &_sysio_incore_dir_ops;
		break;
	case S_IFREG:
		ops = &_sysio_incore_file_ops;
		break;
	default:
		break;
	}
	if (!ops)
		abort();
	ino =
	    _sysio_i_new(ino->i_fs,
			 &icino->ici_fileid,
			 &icino->ici_st
			 1,
			 ops,
			 icino);
#endif
	if (!ino)
		return -ENOMEM;

#ifdef notdef
out:
#endif
	*inop = ino;
	return 0;
}

static int
_sysio_incore_inop_getattr(struct pnode *pno,
			   struct inode *ino,
			   struct intnl_stat *stbuf)
{
	struct incore_inode *icino;

	if (!ino)
		ino = pno->p_base->pb_ino;
	icino = I2IC(ino);
	*stbuf = icino->ici_st;
	return 0;
}

static int
_sysio_incore_inop_setattr(struct pnode *pno,
			   struct inode *ino,
			   unsigned mask,
			   struct intnl_stat *stbuf)
{
	struct incore_inode *icino;
	int	err;

	if (!ino)
		ino = pno->p_base->pb_ino;
	if (!ino)
		return -EBADF;
	icino = I2IC(ino);

	err = 0;
	if (mask & SETATTR_LEN) {
		err = incore_trunc(icino, stbuf->st_size, 1);
		if (err)
			goto out;
		mask &= ~SETATTR_LEN;
	}
	if (mask & SETATTR_MODE) {
		icino->ici_st.st_mode =
		    (icino->ici_st.st_mode & S_IFMT) | (stbuf->st_mode & 07777);
	}
	if (mask & SETATTR_MTIME)
		icino->ici_st.st_mtime = stbuf->st_mtime;
	if (mask & SETATTR_ATIME)
		icino->ici_st.st_atime = stbuf->st_atime;
	if (mask & SETATTR_UID)
		icino->ici_st.st_uid = stbuf->st_uid;
	if (mask & SETATTR_GID)
		icino->ici_st.st_gid = stbuf->st_gid;
	icino->ici_st.st_ctime = time(NULL);

	ino->i_stbuf = icino->ici_st;
out:
	return err;
}

static void *
incore_directory_position(struct intnl_dirent *de,
			  size_t reclen __IS_UNUSED,
			  void *p)
{

	return (void *)de >= p ? de : NULL;
}

struct copy_info {
	void	*data;
	size_t	nbytes;
	unsigned count;
};

/*
 * Eumeration callback.
 *
 * Note:
 * Whiteout entries are never returned.
 */
static void *
incore_directory_enumerate(struct intnl_dirent *de,
			   size_t reclen,
			   struct copy_info *cinfo) {

#ifdef DT_WHT
	if (de->d_type == DT_WHT) {
		/*
		 * Keep going  but skip the copy.
		 */
		return NULL;
	}
#endif
	cinfo->count++;
	if (reclen > cinfo->nbytes)
		return de;
	(void *)memcpy(cinfo->data, de, reclen);
	cinfo->data = (char *)cinfo->data + reclen;
	cinfo->nbytes -= reclen;
	return NULL;
}

static ssize_t
_sysio_incore_dirop_filldirentries(struct inode *ino,
				   _SYSIO_OFF_T *posp,
				   char *buf,
				   size_t nbytes)
{
	struct incore_inode *icino = I2IC(ino);
	off_t	off;
	struct intnl_dirent *de;
	struct copy_info copy_info;

	if (*posp >= icino->ici_st.st_size)
		return 0;

	de =
	    incore_directory_probe(icino->ici_data,
				   icino->ici_st.st_size,
				   *posp,
				   (probe_ty )incore_directory_position,
				   NULL,
				   (char *)icino->ici_data + *posp);
	if (!de) {
		/*
		 * Past EOF.
		 */
		return 0;
	}

	copy_info.data = buf;
	copy_info.nbytes = nbytes;
	copy_info.count = 0;
	off = (char *)de - (char *)icino->ici_data;
	de =
	    incore_directory_probe(de,
				   icino->ici_st.st_size - off,
				   off,
				   (probe_ty )incore_directory_enumerate,
				   NULL,
				   &copy_info);
	icino->ici_st.st_atime = time(NULL);
	if (nbytes == copy_info.nbytes && copy_info.count)
		return -EINVAL;
	nbytes -= copy_info.nbytes;
#if 0
	if (!nbytes)
		return -EOVERFLOW;
#endif
	*posp += nbytes;
	return (ssize_t )nbytes;
}

static struct intnl_dirent *
incore_directory_best_fit(void *data, size_t len, struct lookup_data *ld)
{

	if (!ld->hole.len || len < ld->hole.len) {
		ld->hole.p = data;
		ld->hole.len = len;
	}

	return NULL;
}

static int
incore_directory_insert(struct incore_inode *parent,
			struct qstr *name,
			ino_t inum,
			unsigned char type)
{
	size_t	reclen;
	struct lookup_data lookup_data;
	struct intnl_dirent *de;
	size_t	xt;
	size_t	n;
	size_t	r;

	reclen = INCORE_D_RECLEN(name->len);
	INCORE_LD_INIT(&lookup_data, reclen, name);
	de =
	    incore_directory_probe(parent->ici_data,
				   parent->ici_st.st_size,
				   0,
				   (probe_ty )incore_directory_match,
				   (probe_ty )incore_directory_best_fit,
				   &lookup_data);
	if (de)
		return -EEXIST;
	de = lookup_data.de;
	xt = (char *)lookup_data.de - (char *)parent->ici_data;
	n =
#ifdef _DIRENT_HAVE_D_OFF
	    de->d_off;
#else
	    xt + de->d_reclen;
#endif
	r =
#ifdef _DIRENT_HAVE_D_OFF
	    de->d_reclen;
#else
	    INCORE_D_RECLEN(de->d_namlen);
#endif
	if (!parent->ici_st.st_size ||
	    xt + r + reclen > (size_t )parent->ici_st.st_size) {
		int	err;

		err = incore_trunc(parent, xt + r + reclen, 1);
		if (err)
			return err;
		de = (struct intnl_dirent *)((char *)parent->ici_data + xt);
		n = parent->ici_st.st_size;
	}

#ifdef _DIRENT_HAVE_D_OFF
	de->d_off = xt + r;				/* trim */
#else
	de->d_reclen = r;
#endif
	de = (struct intnl_dirent *)((char *)de + r);				/* reposition */
	xt += r;

#ifndef _DIRENT_HAVE_D_OFF
	/*
	 * Will we split this hole or use all of it?
	 */
	if (lookup_data.hole.len - reclen &&
	    lookup_data.hole.len - reclen <= INCORE_D_RECLEN(1))
		reclen = lookup_data.hole.len;
#endif

	/*
	 * Insert new.
	 */
	de->d_ino = inum;
#ifdef _DIRENT_HAVE_D_OFF
	de->d_off = n;
#endif
	de->d_reclen = reclen;
	de->d_type = type;
	(void )memcpy(de->d_name, name->name, name->len);
#ifdef _DIRENT_HAVE_D_NAMLEN
	de->d_namlen = name->len;
#endif

#ifndef _DIRENT_HAVE_D_OFF
	xt += reclen;
	if (n - xt) {
		/*
		 * White-out remaining part of the hole.
		 */
		(void *)de += reclen;
		de->d_ino = 0;
		de->d_reclen = n - xt;
		de->d_type = DT_WHT;
		de->d_namlen = 0;
	}
#endif

	/*
	 * Update attributes to reflect the new entry.
	 */
	parent->ici_st.st_nlink++;
	assert(parent->ici_st.st_nlink);
	parent->ici_st.st_atime = parent->ici_st.st_mtime = time(NULL);