xref: /freebsd/sys/contrib/openzfs/module/os/freebsd/zfs/vdev_label_os.c (revision 8ac904ce090b1c2e355da8aa122ca2252183f4e1)
1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3  * CDDL HEADER START
4  *
5  * The contents of this file are subject to the terms of the
6  * Common Development and Distribution License (the "License").
7  * You may not use this file except in compliance with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or https://opensource.org/licenses/CDDL-1.0.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 
23 #include <sys/zfs_context.h>
24 #include <sys/spa.h>
25 #include <sys/spa_impl.h>
26 #include <sys/dmu.h>
27 #include <sys/zap.h>
28 #include <sys/vdev.h>
29 #include <sys/vdev_os.h>
30 #include <sys/vdev_impl.h>
31 #include <sys/uberblock_impl.h>
32 #include <sys/metaslab.h>
33 #include <sys/metaslab_impl.h>
34 #include <sys/zio.h>
35 #include <sys/dsl_scan.h>
36 #include <sys/abd.h>
37 #include <sys/fs/zfs.h>
38 
39 int
vdev_label_write_pad2(vdev_t * vd,const char * buf,size_t size)40 vdev_label_write_pad2(vdev_t *vd, const char *buf, size_t size)
41 {
42 	spa_t *spa = vd->vdev_spa;
43 	zio_t *zio;
44 	abd_t *pad2;
45 	int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
46 	    ZIO_FLAG_TRYHARD;
47 	int error;
48 
49 	if (size > VDEV_PAD_SIZE)
50 		return (EINVAL);
51 
52 	if (!vd->vdev_ops->vdev_op_leaf)
53 		return (ENODEV);
54 	if (vdev_is_dead(vd))
55 		return (ENXIO);
56 
57 	ASSERT3U(spa_config_held(spa, SCL_ALL, RW_WRITER), ==, SCL_ALL);
58 
59 	pad2 = abd_alloc_for_io(VDEV_PAD_SIZE, B_TRUE);
60 	abd_copy_from_buf(pad2, buf, size);
61 	abd_zero_off(pad2, size, VDEV_PAD_SIZE - size);
62 
63 	zio = zio_root(spa, NULL, NULL, flags);
64 	vdev_label_write(zio, vd, 0, pad2,
65 	    offsetof(vdev_label_t, vl_be),
66 	    VDEV_PAD_SIZE, NULL, NULL, flags);
67 	error = zio_wait(zio);
68 
69 	abd_free(pad2);
70 	return (error);
71 }
72 
73 static void
vdev_child_done(zio_t * zio)74 vdev_child_done(zio_t *zio)
75 {
76 	zio_t *pio = zio->io_private;
77 
78 	mutex_enter(&pio->io_lock);
79 	pio->io_error = zio_worst_error(pio->io_error, zio->io_error);
80 	mutex_exit(&pio->io_lock);
81 }
82 
83 /*
84  * Check if the reserved boot area is in-use.
85  *
86  * When booting FreeBSD with an MBR partition with ZFS, the zfsboot file
87  * (which understands the ZFS file system) is written to the ZFS BOOT
88  * reserve area (at offset 512K). We check for that here before attaching
89  * a disk to raidz which would then corrupt this boot data.
90  */
91 int
vdev_check_boot_reserve(spa_t * spa,vdev_t * childvd)92 vdev_check_boot_reserve(spa_t *spa, vdev_t *childvd)
93 {
94 	ASSERT(childvd->vdev_ops->vdev_op_leaf);
95 
96 	size_t size = 1ULL << childvd->vdev_top->vdev_ashift;
97 	abd_t *abd = abd_alloc_linear(size, B_FALSE);
98 
99 	zio_t *pio = zio_root(spa, NULL, NULL, 0);
100 	/*
101 	 * Note: zio_vdev_child_io() adds VDEV_LABEL_START_SIZE to the offset
102 	 * to calculate the physical offset to write to.  Passing in a negative
103 	 * offset lets us access the boot area.
104 	 */
105 	zio_nowait(zio_vdev_child_io(pio, NULL, childvd,
106 	    VDEV_BOOT_OFFSET - VDEV_LABEL_START_SIZE, abd, size, ZIO_TYPE_READ,
107 	    ZIO_PRIORITY_ASYNC_READ, 0, vdev_child_done, pio));
108 	zio_wait(pio);
109 
110 	unsigned char *buf = abd_to_buf(abd);
111 
112 	/*
113 	 * The BTX server has a special header at the begining.
114 	 *
115 	 * btx_hdr:	.byte 0xeb		# Machine ID
116 	 *		.byte 0xe		# Header size
117 	 *		.ascii "BTX"		# Magic
118 	 *		.byte 0x1		# Major version
119 	 *		.byte 0x2		# Minor version
120 	 *		.byte BTX_FLAGS		# Flags
121 	 */
122 	if (buf[0] == 0xeb && buf[1] == 0x0e &&
123 	    buf[2] == 'B' && buf[3] == 'T' && buf[4] == 'X') {
124 		abd_free(abd);
125 		return (EBUSY);
126 	}
127 
128 	abd_free(abd);
129 	return (0);
130 }
131