inode.c

linux 内核源代码

	if ((name->len == 1 && memcmp(name->name, ".", 1) == 0) ||
	    (name->len == 2 && memcmp(name->name, "..", 2) == 0 &&
	     dir == sb->s_root->d_inode)) {
		igrab(dir);
		return dir;
	}

	if (gfs2_glock_is_locked_by_me(dip->i_gl) == 0) {
		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
		if (error)
			return ERR_PTR(error);
		unlock = 1;
	}

	if (!is_root) {
		error = permission(dir, MAY_EXEC, NULL);
		if (error)
			goto out;
	}

	inode = gfs2_dir_search(dir, name);
	if (IS_ERR(inode))
		error = PTR_ERR(inode);
out:
	if (unlock)
		gfs2_glock_dq_uninit(&d_gh);
	if (error == -ENOENT)
		return NULL;
	return inode ? inode : ERR_PTR(error);
}

static void gfs2_inum_range_in(struct gfs2_inum_range_host *ir, const void *buf)
{
	const struct gfs2_inum_range *str = buf;

	ir->ir_start = be64_to_cpu(str->ir_start);
	ir->ir_length = be64_to_cpu(str->ir_length);
}

static void gfs2_inum_range_out(const struct gfs2_inum_range_host *ir, void *buf)
{
	struct gfs2_inum_range *str = buf;

	str->ir_start = cpu_to_be64(ir->ir_start);
	str->ir_length = cpu_to_be64(ir->ir_length);
}

static int pick_formal_ino_1(struct gfs2_sbd *sdp, u64 *formal_ino)
{
	struct gfs2_inode *ip = GFS2_I(sdp->sd_ir_inode);
	struct buffer_head *bh;
	struct gfs2_inum_range_host ir;
	int error;

	error = gfs2_trans_begin(sdp, RES_DINODE, 0);
	if (error)
		return error;
	mutex_lock(&sdp->sd_inum_mutex);

	error = gfs2_meta_inode_buffer(ip, &bh);
	if (error) {
		mutex_unlock(&sdp->sd_inum_mutex);
		gfs2_trans_end(sdp);
		return error;
	}

	gfs2_inum_range_in(&ir, bh->b_data + sizeof(struct gfs2_dinode));

	if (ir.ir_length) {
		*formal_ino = ir.ir_start++;
		ir.ir_length--;
		gfs2_trans_add_bh(ip->i_gl, bh, 1);
		gfs2_inum_range_out(&ir,
				    bh->b_data + sizeof(struct gfs2_dinode));
		brelse(bh);
		mutex_unlock(&sdp->sd_inum_mutex);
		gfs2_trans_end(sdp);
		return 0;
	}

	brelse(bh);

	mutex_unlock(&sdp->sd_inum_mutex);
	gfs2_trans_end(sdp);

	return 1;
}

static int pick_formal_ino_2(struct gfs2_sbd *sdp, u64 *formal_ino)
{
	struct gfs2_inode *ip = GFS2_I(sdp->sd_ir_inode);
	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_inum_inode);
	struct gfs2_holder gh;
	struct buffer_head *bh;
	struct gfs2_inum_range_host ir;
	int error;

	error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
	if (error)
		return error;

	error = gfs2_trans_begin(sdp, 2 * RES_DINODE, 0);
	if (error)
		goto out;
	mutex_lock(&sdp->sd_inum_mutex);

	error = gfs2_meta_inode_buffer(ip, &bh);
	if (error)
		goto out_end_trans;

	gfs2_inum_range_in(&ir, bh->b_data + sizeof(struct gfs2_dinode));

	if (!ir.ir_length) {
		struct buffer_head *m_bh;
		u64 x, y;
		__be64 z;

		error = gfs2_meta_inode_buffer(m_ip, &m_bh);
		if (error)
			goto out_brelse;

		z = *(__be64 *)(m_bh->b_data + sizeof(struct gfs2_dinode));
		x = y = be64_to_cpu(z);
		ir.ir_start = x;
		ir.ir_length = GFS2_INUM_QUANTUM;
		x += GFS2_INUM_QUANTUM;
		if (x < y)
			gfs2_consist_inode(m_ip);
		z = cpu_to_be64(x);
		gfs2_trans_add_bh(m_ip->i_gl, m_bh, 1);
		*(__be64 *)(m_bh->b_data + sizeof(struct gfs2_dinode)) = z;

		brelse(m_bh);
	}

	*formal_ino = ir.ir_start++;
	ir.ir_length--;

	gfs2_trans_add_bh(ip->i_gl, bh, 1);
	gfs2_inum_range_out(&ir, bh->b_data + sizeof(struct gfs2_dinode));

out_brelse:
	brelse(bh);
out_end_trans:
	mutex_unlock(&sdp->sd_inum_mutex);
	gfs2_trans_end(sdp);
out:
	gfs2_glock_dq_uninit(&gh);
	return error;
}

static int pick_formal_ino(struct gfs2_sbd *sdp, u64 *inum)
{
	int error;

	error = pick_formal_ino_1(sdp, inum);
	if (error <= 0)
		return error;

	error = pick_formal_ino_2(sdp, inum);

	return error;
}

/**
 * create_ok - OK to create a new on-disk inode here?
 * @dip:  Directory in which dinode is to be created
 * @name:  Name of new dinode
 * @mode:
 *
 * Returns: errno
 */

static int create_ok(struct gfs2_inode *dip, const struct qstr *name,
		     unsigned int mode)
{
	int error;

	error = permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, NULL);
	if (error)
		return error;

	/*  Don't create entries in an unlinked directory  */
	if (!dip->i_inode.i_nlink)
		return -EPERM;

	error = gfs2_dir_check(&dip->i_inode, name, NULL);
	switch (error) {
	case -ENOENT:
		error = 0;
		break;
	case 0:
		return -EEXIST;
	default:
		return error;
	}

	if (dip->i_di.di_entries == (u32)-1)
		return -EFBIG;
	if (S_ISDIR(mode) && dip->i_inode.i_nlink == (u32)-1)
		return -EMLINK;

	return 0;
}

static void munge_mode_uid_gid(struct gfs2_inode *dip, unsigned int *mode,
			       unsigned int *uid, unsigned int *gid)
{
	if (GFS2_SB(&dip->i_inode)->sd_args.ar_suiddir &&
	    (dip->i_inode.i_mode & S_ISUID) && dip->i_inode.i_uid) {
		if (S_ISDIR(*mode))
			*mode |= S_ISUID;
		else if (dip->i_inode.i_uid != current->fsuid)
			*mode &= ~07111;
		*uid = dip->i_inode.i_uid;
	} else
		*uid = current->fsuid;

	if (dip->i_inode.i_mode & S_ISGID) {
		if (S_ISDIR(*mode))
			*mode |= S_ISGID;
		*gid = dip->i_inode.i_gid;
	} else
		*gid = current->fsgid;
}

static int alloc_dinode(struct gfs2_inode *dip, u64 *no_addr, u64 *generation)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	int error;

	gfs2_alloc_get(dip);

	dip->i_alloc.al_requested = RES_DINODE;
	error = gfs2_inplace_reserve(dip);
	if (error)
		goto out;

	error = gfs2_trans_begin(sdp, RES_RG_BIT + RES_STATFS, 0);
	if (error)
		goto out_ipreserv;

	*no_addr = gfs2_alloc_di(dip, generation);

	gfs2_trans_end(sdp);

out_ipreserv:
	gfs2_inplace_release(dip);
out:
	gfs2_alloc_put(dip);
	return error;
}

/**
 * init_dinode - Fill in a new dinode structure
 * @dip: the directory this inode is being created in
 * @gl: The glock covering the new inode
 * @inum: the inode number
 * @mode: the file permissions
 * @uid:
 * @gid:
 *
 */

static void init_dinode(struct gfs2_inode *dip, struct gfs2_glock *gl,
			const struct gfs2_inum_host *inum, unsigned int mode,
			unsigned int uid, unsigned int gid,
			const u64 *generation, dev_t dev, struct buffer_head **bhp)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct gfs2_dinode *di;
	struct buffer_head *dibh;
	struct timespec tv = CURRENT_TIME;

	dibh = gfs2_meta_new(gl, inum->no_addr);
	gfs2_trans_add_bh(gl, dibh, 1);
	gfs2_metatype_set(dibh, GFS2_METATYPE_DI, GFS2_FORMAT_DI);
	gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
	di = (struct gfs2_dinode *)dibh->b_data;

	di->di_num.no_formal_ino = cpu_to_be64(inum->no_formal_ino);
	di->di_num.no_addr = cpu_to_be64(inum->no_addr);
	di->di_mode = cpu_to_be32(mode);
	di->di_uid = cpu_to_be32(uid);
	di->di_gid = cpu_to_be32(gid);
	di->di_nlink = 0;
	di->di_size = 0;
	di->di_blocks = cpu_to_be64(1);
	di->di_atime = di->di_mtime = di->di_ctime = cpu_to_be64(tv.tv_sec);
	di->di_major = cpu_to_be32(MAJOR(dev));
	di->di_minor = cpu_to_be32(MINOR(dev));
	di->di_goal_meta = di->di_goal_data = cpu_to_be64(inum->no_addr);
	di->di_generation = cpu_to_be64(*generation);
	di->di_flags = 0;

	if (S_ISREG(mode)) {
		if ((dip->i_di.di_flags & GFS2_DIF_INHERIT_JDATA) ||
		    gfs2_tune_get(sdp, gt_new_files_jdata))
			di->di_flags |= cpu_to_be32(GFS2_DIF_JDATA);
		if ((dip->i_di.di_flags & GFS2_DIF_INHERIT_DIRECTIO) ||
		    gfs2_tune_get(sdp, gt_new_files_directio))
			di->di_flags |= cpu_to_be32(GFS2_DIF_DIRECTIO);
	} else if (S_ISDIR(mode)) {
		di->di_flags |= cpu_to_be32(dip->i_di.di_flags &
					    GFS2_DIF_INHERIT_DIRECTIO);
		di->di_flags |= cpu_to_be32(dip->i_di.di_flags &
					    GFS2_DIF_INHERIT_JDATA);
	}

	di->__pad1 = 0;
	di->di_payload_format = cpu_to_be32(S_ISDIR(mode) ? GFS2_FORMAT_DE : 0);
	di->di_height = 0;
	di->__pad2 = 0;
	di->__pad3 = 0;
	di->di_depth = 0;
	di->di_entries = 0;
	memset(&di->__pad4, 0, sizeof(di->__pad4));
	di->di_eattr = 0;
	di->di_atime_nsec = cpu_to_be32(tv.tv_nsec);
	di->di_mtime_nsec = cpu_to_be32(tv.tv_nsec);
	di->di_ctime_nsec = cpu_to_be32(tv.tv_nsec);
	memset(&di->di_reserved, 0, sizeof(di->di_reserved));
	
	set_buffer_uptodate(dibh);

	*bhp = dibh;
}

static int make_dinode(struct gfs2_inode *dip, struct gfs2_glock *gl,
		       unsigned int mode, const struct gfs2_inum_host *inum,
		       const u64 *generation, dev_t dev, struct buffer_head **bhp)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	unsigned int uid, gid;
	int error;

	munge_mode_uid_gid(dip, &mode, &uid, &gid);
	gfs2_alloc_get(dip);

	error = gfs2_quota_lock(dip, uid, gid);
	if (error)
		goto out;

	error = gfs2_quota_check(dip, uid, gid);
	if (error)
		goto out_quota;

	error = gfs2_trans_begin(sdp, RES_DINODE + RES_QUOTA, 0);
	if (error)
		goto out_quota;

	init_dinode(dip, gl, inum, mode, uid, gid, generation, dev, bhp);
	gfs2_quota_change(dip, +1, uid, gid);
	gfs2_trans_end(sdp);

out_quota:
	gfs2_quota_unlock(dip);
out:
	gfs2_alloc_put(dip);
	return error;
}

static int link_dinode(struct gfs2_inode *dip, const struct qstr *name,
		       struct gfs2_inode *ip)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct gfs2_alloc *al;
	int alloc_required;
	struct buffer_head *dibh;
	int error;

	al = gfs2_alloc_get(dip);

	error = gfs2_quota_lock(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
	if (error)
		goto fail;

	error = alloc_required = gfs2_diradd_alloc_required(&dip->i_inode, name);
	if (alloc_required < 0)
		goto fail;
	if (alloc_required) {
		error = gfs2_quota_check(dip, dip->i_inode.i_uid, dip->i_inode.i_gid);
		if (error)
			goto fail_quota_locks;

		al->al_requested = sdp->sd_max_dirres;

		error = gfs2_inplace_reserve(dip);
		if (error)
			goto fail_quota_locks;

		error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
					 al->al_rgd->rd_length +
					 2 * RES_DINODE +
					 RES_STATFS + RES_QUOTA, 0);
		if (error)
			goto fail_ipreserv;
	} else {
		error = gfs2_trans_begin(sdp, RES_LEAF + 2 * RES_DINODE, 0);
		if (error)
			goto fail_quota_locks;
	}

	error = gfs2_dir_add(&dip->i_inode, name, ip, IF2DT(ip->i_inode.i_mode));
	if (error)
		goto fail_end_trans;

	error = gfs2_meta_inode_buffer(ip, &dibh);
	if (error)
		goto fail_end_trans;
	ip->i_inode.i_nlink = 1;
	gfs2_trans_add_bh(ip->i_gl, dibh, 1);
	gfs2_dinode_out(ip, dibh->b_data);
	brelse(dibh);
	return 0;

fail_end_trans:
	gfs2_trans_end(sdp);

fail_ipreserv:
	if (dip->i_alloc.al_rgd)
		gfs2_inplace_release(dip);

fail_quota_locks:
	gfs2_quota_unlock(dip);

fail:
	gfs2_alloc_put(dip);
	return error;
}

static int gfs2_security_init(struct gfs2_inode *dip, struct gfs2_inode *ip)
{
	int err;
	size_t len;
	void *value;
	char *name;
	struct gfs2_ea_request er;

	err = security_inode_init_security(&ip->i_inode, &dip->i_inode,
					   &name, &value, &len);

	if (err) {
		if (err == -EOPNOTSUPP)
			return 0;
		return err;
	}

	memset(&er, 0, sizeof(struct gfs2_ea_request));

	er.er_type = GFS2_EATYPE_SECURITY;
	er.er_name = name;
	er.er_data = value;
	er.er_name_len = strlen(name);
	er.er_data_len = len;

	err = gfs2_ea_set_i(ip, &er);

	kfree(value);
	kfree(name);

	return err;
}

/**
 * gfs2_createi - Create a new inode
 * @ghs: An array of two holders
 * @name: The name of the new file
 * @mode: the permissions on the new inode
 *
 * @ghs[0] is an initialized holder for the directory
 * @ghs[1] is the holder for the inode lock
 *
 * If the return value is not NULL, the glocks on both the directory and the new
 * file are held.  A transaction has been started and an inplace reservation
 * is held, as well.
 *
 * Returns: An inode