module/os/freebsd/zfs/vdev_label_os.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 #include <sys/zfs_context.h>
  23 #include <sys/spa.h>
  24 #include <sys/spa_impl.h>
  25 #include <sys/dmu.h>
  26 #include <sys/zap.h>
  27 #include <sys/vdev.h>
  28 #include <sys/vdev_os.h>
  29 #include <sys/vdev_impl.h>
  30 #include <sys/uberblock_impl.h>
  31 #include <sys/metaslab.h>
  32 #include <sys/metaslab_impl.h>
  33 #include <sys/zio.h>
  34 #include <sys/dsl_scan.h>
  35 #include <sys/abd.h>
  36 #include <sys/fs/zfs.h>
  37
  38 int
  39 vdev_label_write_pad2(vdev_t *vd, const char *buf, size_t size)
  40 {
  41         spa_t *spa = vd->vdev_spa;
  42         zio_t *zio;
  43         abd_t *pad2;
  44         int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
  45         int error;
  46
  47         if (size > VDEV_PAD_SIZE)
  48                 return (EINVAL);
  49
  50         if (!vd->vdev_ops->vdev_op_leaf)
  51                 return (ENODEV);
  52         if (vdev_is_dead(vd))
  53                 return (ENXIO);
  54
  55         ASSERT3U(spa_config_held(spa, SCL_ALL, RW_WRITER), ==, SCL_ALL);
  56
  57         pad2 = abd_alloc_for_io(VDEV_PAD_SIZE, B_TRUE);
  58         abd_copy_from_buf(pad2, buf, size);
  59         abd_zero_off(pad2, size, VDEV_PAD_SIZE - size);
  60
  61 retry:
  62         zio = zio_root(spa, NULL, NULL, flags);
  63         vdev_label_write(zio, vd, 0, pad2,
  64             offsetof(vdev_label_t, vl_be),
  65             VDEV_PAD_SIZE, NULL, NULL, flags);
  66         error = zio_wait(zio);
  67         if (error != 0 && !(flags & ZIO_FLAG_TRYHARD)) {
  68                 flags |= ZIO_FLAG_TRYHARD;
  69                 goto retry;
  70         }
  71
  72         abd_free(pad2);
  73         return (error);
  74 }
  75
  76 static void
  77 vdev_child_done(zio_t *zio)
  78 {
  79         zio_t *pio = zio->io_private;
  80
  81         mutex_enter(&pio->io_lock);
  82         pio->io_error = zio_worst_error(pio->io_error, zio->io_error);
  83         mutex_exit(&pio->io_lock);
  84 }
  85
  86 /*
  87  * Check if the reserved boot area is in-use.
  88  *
  89  * When booting FreeBSD with an MBR partition with ZFS, the zfsboot file
  90  * (which understands the ZFS file system) is written to the ZFS BOOT
  91  * reserve area (at offset 512K). We check for that here before attaching
  92  * a disk to raidz which would then corrupt this boot data.
  93  */
  94 int
  95 vdev_check_boot_reserve(spa_t *spa, vdev_t *childvd)
  96 {
  97         ASSERT(childvd->vdev_ops->vdev_op_leaf);
  98
  99         size_t size = SPA_MINBLOCKSIZE;
 100         abd_t *abd = abd_alloc_linear(size, B_FALSE);
 101
 102         zio_t *pio = zio_root(spa, NULL, NULL, 0);
 103         /*
 104          * Note: zio_vdev_child_io() adds VDEV_LABEL_START_SIZE to the offset
 105          * to calculate the physical offset to write to.  Passing in a negative
 106          * offset lets us access the boot area.
 107          */
 108         zio_nowait(zio_vdev_child_io(pio, NULL, childvd,
 109             VDEV_BOOT_OFFSET - VDEV_LABEL_START_SIZE, abd, size, ZIO_TYPE_READ,
 110             ZIO_PRIORITY_ASYNC_READ, 0, vdev_child_done, pio));
 111         zio_wait(pio);
 112
 113         unsigned char *buf = abd_to_buf(abd);
 114
 115         /*
 116          * The BTX server has a special header at the begining.
 117          *
 118          * btx_hdr:     .byte 0xeb              # Machine ID
 119          *              .byte 0xe               # Header size
 120          *              .ascii "BTX"            # Magic
 121          *              .byte 0x1               # Major version
 122          *              .byte 0x2               # Minor version
 123          *              .byte BTX_FLAGS         # Flags
 124          */
 125         if (buf[0] == 0xeb && buf[1] == 0x0e &&
 126             buf[2] == 'B' && buf[3] == 'T' && buf[4] == 'X') {
 127                 abd_free(abd);
 128                 return (EBUSY);
 129         }
 130
 131         abd_free(abd);
 132         return (0);
 133 }