11182 loader: Distinguish between "no partition" and "choose best partition" with a constant.
Review Request #1961 — Created June 3, 2019 and submitted
https://svnweb.freebsd.org/base?view=revision&revision=345477 The values of the d_slice and d_partition fields of a disk_devdesc have a few values with special meanings in the disk_open() routine. Through various evolutions of the loader code over time, a d_partition value of -1 has meant both "use the first ufs partition found in the bsd label" and "don't open a bsd partition at all, open the raw slice." This defines a new special value of -2 to mean open the raw slice, and it gives symbolic names to all the special values used in d_slice and d_partition, and adjusts all existing uses of those fields to use the new constants. The phab review for this timed out without being accepted, but I'm still citing it below because there is useful commentary there. Differential Revision: https://reviews.freebsd.org/D19262 https://svnweb.freebsd.org/base?view=revision&revision=r346675 Restore the ability to open a raw disk or partition in loader(8). The disk_open() function searches for "the best partition" when slice and partition information is not provided as part of the device name. As of r345477 the slice and partition fields of a disk_devdesc are initialized to D_SLICEWILD and D_PARTWILD; in the past they were initialized to -1, which was sometimes interpreted as meaning 'wildcard' and sometimes as 'open the raw partition' depending on the context. So as an unintended side effect of r345477 it became basically impossible to ever open a disk or partition without doing the 'best partition' search. One visible effect of that was the inability to open the raw disk to read the partition table correctly in zfs_probe_dev(), leading to failures to find the zfs pool unless it was on the first partition. Now instead of always initializing slice and partition to wildcards, the disk_parsedev() function initializes them based on the presence of a path/file name following the device. If there is any path or filename following the ':' that ends the device name, then slice and partition are initialized to D_SLICEWILD and D_PARTWILD. If there is nothing after the ':' then it is considered to be a request to open the raw device or partition itself (not a file stored within it), and the fields are initialized to D_SLICENONE and D_PARTNONE. With this change in place, all the tests in src/tools/boot are succesful again, including the recently-added cases of booting from a zfs pool on a partition other than slice 1 of the device. https://svnweb.freebsd.org/base?view=revision&revision=r346984 Use D_PARTISGPT rather than bare 255 These three cases dovetail with other places in the code where we use or set D_PARTISGPT when we mean that the partitioning scheme is GPT. Use this #define to make the code easier to undertand. Reviewed by: tsoome@ Differential Revision: https://reviews.freebsd.org/D20122 use local partdev device descriptor to read disk global partition table. Check if we have VTOC at the start of the disk. In case the D_PARTISGPT was used with non-GPT table, use D_PARTWILD to allow the autodetection code to work - D_PARTNONE means we should open raw MBR partition. /code/illumos-gate/usr/src/tools/proto/root_i386-nd/opt/onbld/bin/i386/smatch: ../../common/disk.c:310 disk_open() warn: was && intended here instead of ||? /code/illumos-gate/usr/src/tools/proto/root_i386-nd/opt/onbld/bin/i386/smatch: ../../common/disk.c:327 disk_open() warn: was && intended here instead of ||?