Date: Fri, 24 Mar 1995 03:31:41 +1000 From: Bruce Evans <bde@zeta.org.au> To: current@FreeBSD.org Cc: bde@zeta.org.au Subject: Re: cvs commit: src/sys/scsi sd.c Message-ID: <199503231731.DAA22454@godzilla.zeta.org.au>
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I have committed the the changes for slices to the sd driver: --- bde 95/03/23 08:09:02 Modified: sys/scsi sd.c Log: Support disk slices. This involves mainly replacing inline code with function calls. Broken tracking of open partitions gets fixed as a side effect. Races in sdopen() and sdioctl() become more numerous than before. Close the device in sdsize(). Media removal could not have worked right when unused swap devices were held open. There may now be a problem with used swap devices not being held open. Fix ancient operator precedence bug in sddump(). It may have been possible to attempt dumping to unloaded media. Remove NetBSD ifdefs. We're too different now, and the NetBSD driver was already too different for them to be relevant. Remove support for soft write protection. There are no ioctls to set it, and this driver never set it either. It was used in the wd driver to disable writing to unlabelled disk, but we want to support writing to foreign partitions on unlabeled disks. Clean up some formatting and restore some old-style function headers. --- This should not affect the operation of normal BSD partitions sd0[a-c], sd0[e-h], rsd0[a-c] and rsd0[e-h] (all examples assume drive 0). The d partition should become available as a normal partition. The whole disk can be accessed as device sd0 or rsd0 instead. Use MAKEDEV to create these devices if you don't already have them. Programs that want to access the d partition may break. There aren't many such programs - only fdisk and sysinstall. sysinstall breaks, but `fdisk /dev/rsd0' should work. There will be some new boot messages such as the following: sd0s1: start 32, end = 262143, size 262112: OK sd0s2: start 262144, end = 1816575, size 1554432: OK sd0s3: start 1816576, end = 2078719, size 262144: OK sd0s5: start 1816608, end = 2078719, size 262112: OK sd1s1: start 32, end = 524287, size 524256: OK sd1s2: start 524288, end = 1572863, size 1048576: OK sd0s1: start 32, end = 262143, size 262112: OK sd0s2: start 262144, end = 1816575, size 1554432: OK sd0s3: start 1816576, end = 2078719, size 262144: OK sd0s5: start 1816608, end = 2078719, size 262112: OK [messages not related to slices...] sd0s1: start 32, end = 262143, size 262112: OK sd0s2: start 262144, end = 1816575, size 1554432: OK sd0s3: start 1816576, end = 2078719, size 262144: OK sd0s5: start 1816608, end = 2078719, size 262112: OK sd0s1 is an MSDOS partition. I use a line "/dev/sd0s1 /dosC msdos ..." in /etc/fstab to mount this. If you have an MSDOS partition in the disklabel, then you should see additional messages about the partition not being valid because it is not within the slice and the partition should be replaced by one of size 0 and any reference to it in /etc/fstab should stop working. These problems may be fixed by editing the label and /etc/fstab. The on-disk label isn't changed automatically. Run MAKEDEV to create new slices if necessary. sd0s2 is a FreeBSD slice. The first BSD slice is aliased to slice 0 and `s0' is not present in the names for slice 0. This allows you to use the old names and device inodes. You may wire down the slice number by never using the slice 0 alias. Run `MAKEDEV sd0s2h' to create the partitions for sd0s2. sd0s3 is an extended DOSpartition. Extended DOSpartitions contain further extended DOSpartitions and slice and are not suitable for holding file systems. Slices are only created for primary extended DOSpartitions. sd0s5 is a logical MSDOS drive within sd0s3. There may be up to 26 slices of any type within extended DOSpartition(s). There may be multiple FreeBSD slices, but currently, booting is only supported from the first slice, the boot slice must be a primary DOSpartition, and fdisk doesn't support slices within extended DOSpartitions. Run `MAKEDEV sd0s5' to create the non-default slice sd0s5. sd1s1 is a DOS slice. sd1s2 is a FreeBSD slice. The messages for sd0 are repeated twice because the partition table and labels are reread whenever a sliced disk device is opened when there are no current opens on it, and devices sd0 is opened and fully closed several times while booting. This wart is currently required for rereading the changed partition tables. It also helps debug partition tables and disk labels. If sd0 is the root device, then after root is mounted the messages for sd0 should never be seen again. Mounting and unmounting sd1a would cause lots of messages. The procedure for putting partition tables and labels on disk is not much changed from before. It is best practiced on the vn device. The main new points are that sd0d is no longer the whole disk (this affects fdisk) and slices in /etc/disktab must be relative, i.e., the c partition must start at 0, and all the partitions must fit in the slice. If there are no DOSpartitions, then slice 0 is supposed to be the whole disk. Note that boot blocks contain a bogus DOSpartition table so you will have to do some work to reach this pure state. The whole-disk device sd0s1 has an in-core-only read-only label. fdisk will print a warning when it can't write this label. I found old mail giving examples of some more error messages: >>sd0: rejecting partition in BSD label: it isn't entirely within the slice >>sd0e: start 32, end 262143, size 262112 >I still have a slice for a DOS primary partition on 'e' for backwardsness. >The message omits the position of the slice because it was printed >immediately above. >>sd1: raw partition size != slice size >>sd1: start 6144, end 825343, size 819200 >>sd1c: start 6144, end 823963, size 817820 The messages may have changed slightly since then. Bruce
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