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geom(4): Kill GEOM_PART_EBR_COMPAT option

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Take advantage of Warner's nice new real GEOM aliasing system and use it for
aliased partition names that actually work.

Our canonical EBR partition name is the weird, not-default-on-x86-prior-to-
this-revision "da1p4+00001234."  However, if compatibility mode (tunable
kern.geom.part.ebr.compat_aliases) is enabled (1, default), we continue to
provide the alias names like "da1p5" in addition to the weird canonical
names.

Naming partition providers was just one aspect of the COMPAT knob; in
addition it limited mutability, in part because it did not preserve existing
EBR header content aside from that of LBA 0.  This change saves the EBR
header for LBA 0, as well as for every EBR partition encountered.  That way,
when we write out the EBR partition table on modification, we can restore
any bootloader or other metadata in both LBA0 (the first data-containing EBR
may start after 0) as well as every logical EBR we read from the disk, and
only update the geometry metadata and linked list pointers that describe the
actual partitioning.

(This change does not add support for the 'bootcode' verb to EBR.)

PR:		232463
Reported by:	Manish Jain <bourne.identity AT hotmail.com>
Discussed with:	ae (no objection)
Relnotes:	maybe
Differential Revision:	https://reviews.freebsd.org/D24939
This commit is contained in:
Conrad Meyer 2020-07-01 02:16:36 +00:00
parent 80a315ffb6
commit 64612d4e44
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=362823
5 changed files with 83 additions and 59 deletions
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1
sys/amd64/conf/DEFAULTS
View File

@ -18,7 +18,6 @@ device uart_ns8250
# Default partitioning schemes
options GEOM_PART_BSD
options GEOM_PART_EBR
options GEOM_PART_EBR_COMPAT
options GEOM_PART_MBR
options GEOM_PART_GPT

1
sys/conf/NOTES
View File

@ -171,7 +171,6 @@ options GEOM_PART_APM # Apple partitioning
options GEOM_PART_BSD # BSD disklabel
options GEOM_PART_BSD64 # BSD disklabel64
options GEOM_PART_EBR # Extended Boot Records
options GEOM_PART_EBR_COMPAT # Backward compatible partition names
options GEOM_PART_GPT # GPT partitioning
options GEOM_PART_LDM # Logical Disk Manager
options GEOM_PART_MBR # MBR partitioning

1
sys/conf/options
View File

@ -125,7 +125,6 @@ GEOM_PART_APM opt_geom.h
GEOM_PART_BSD opt_geom.h
GEOM_PART_BSD64 opt_geom.h
GEOM_PART_EBR opt_geom.h
GEOM_PART_EBR_COMPAT opt_geom.h
GEOM_PART_GPT opt_geom.h
GEOM_PART_LDM opt_geom.h
GEOM_PART_MBR opt_geom.h

138
sys/geom/part/g_part_ebr.c
View File

@ -52,40 +52,48 @@ __FBSDID("$FreeBSD$");
FEATURE(geom_part_ebr,
"GEOM partitioning class for extended boot records support");
#if defined(GEOM_PART_EBR_COMPAT)
FEATURE(geom_part_ebr_compat,
"GEOM EBR partitioning class: backward-compatible partition names");
#endif
SYSCTL_DECL(_kern_geom_part);
static SYSCTL_NODE(_kern_geom_part, OID_AUTO, ebr, CTLFLAG_RW | CTLFLAG_MPSAFE,
0, "GEOM_PART_EBR Extended Boot Record");
static bool compat_aliases = true;
SYSCTL_BOOL(_kern_geom_part_ebr, OID_AUTO, compat_aliases,
CTLFLAG_RDTUN, &compat_aliases, 0,
"Set non-zero to enable EBR compatibility alias names (e.g., ada0p5)");
#define EBRNAMFMT "+%08u"
#define EBRSIZE 512
struct g_part_ebr_table {
struct g_part_table base;
#ifndef GEOM_PART_EBR_COMPAT
u_char ebr[EBRSIZE];
#endif
u_char lba0_ebr[EBRSIZE];
};
struct g_part_ebr_entry {
struct g_part_entry base;
struct dos_partition ent;
u_char ebr[EBRSIZE];
u_int ebr_compat_idx;
};
static int g_part_ebr_add(struct g_part_table *, struct g_part_entry *,
struct g_part_parms *);
static void g_part_ebr_add_alias(struct g_part_table *, struct g_provider *,
struct g_part_entry *, const char *);
static int g_part_ebr_create(struct g_part_table *, struct g_part_parms *);
static int g_part_ebr_destroy(struct g_part_table *, struct g_part_parms *);
static void g_part_ebr_dumpconf(struct g_part_table *, struct g_part_entry *,
struct sbuf *, const char *);
static int g_part_ebr_dumpto(struct g_part_table *, struct g_part_entry *);
#if defined(GEOM_PART_EBR_COMPAT)
static void g_part_ebr_fullname(struct g_part_table *, struct g_part_entry *,
struct sbuf *, const char *);
#endif
static int g_part_ebr_modify(struct g_part_table *, struct g_part_entry *,
struct g_part_parms *);
static const char *g_part_ebr_name(struct g_part_table *, struct g_part_entry *,
char *, size_t);
static struct g_provider *g_part_ebr_new_provider(struct g_part_table *,
struct g_geom *, struct g_part_entry *, const char *);
static int g_part_ebr_precheck(struct g_part_table *, enum g_part_ctl,
struct g_part_parms *);
static int g_part_ebr_probe(struct g_part_table *, struct g_consumer *);
@ -100,15 +108,14 @@ static int g_part_ebr_resize(struct g_part_table *, struct g_part_entry *,
static kobj_method_t g_part_ebr_methods[] = {
KOBJMETHOD(g_part_add, g_part_ebr_add),
KOBJMETHOD(g_part_add_alias, g_part_ebr_add_alias),
KOBJMETHOD(g_part_create, g_part_ebr_create),
KOBJMETHOD(g_part_destroy, g_part_ebr_destroy),
KOBJMETHOD(g_part_dumpconf, g_part_ebr_dumpconf),
KOBJMETHOD(g_part_dumpto, g_part_ebr_dumpto),
#if defined(GEOM_PART_EBR_COMPAT)
KOBJMETHOD(g_part_fullname, g_part_ebr_fullname),
#endif
KOBJMETHOD(g_part_modify, g_part_ebr_modify),
KOBJMETHOD(g_part_name, g_part_ebr_name),
KOBJMETHOD(g_part_new_provider, g_part_ebr_new_provider),
KOBJMETHOD(g_part_precheck, g_part_ebr_precheck),
KOBJMETHOD(g_part_probe, g_part_ebr_probe),
KOBJMETHOD(g_part_read, g_part_ebr_read),
@ -171,7 +178,7 @@ ebr_entry_link(struct g_part_table *table, uint32_t start, uint32_t end,
buf[0] = 0 /* dp_flag */;
ebr_set_chs(table, start, &buf[3] /* dp_scyl */, &buf[1] /* dp_shd */,
&buf[2] /* dp_ssect */);
buf[4] = 5 /* dp_typ */;
buf[4] = DOSPTYP_EXT /* dp_typ */;
ebr_set_chs(table, end, &buf[7] /* dp_ecyl */, &buf[5] /* dp_ehd */,
&buf[6] /* dp_esect */);
le32enc(buf + 8, start);
@ -249,7 +256,9 @@ g_part_ebr_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
{
struct g_provider *pp;
struct g_part_ebr_entry *entry;
struct g_part_entry *iter;
uint32_t start, size;
u_int idx;
if (gpp->gpp_parms & G_PART_PARM_LABEL)
return (EINVAL);
@ -276,9 +285,48 @@ g_part_ebr_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
&entry->ent.dp_shd, &entry->ent.dp_ssect);
ebr_set_chs(basetable, baseentry->gpe_end, &entry->ent.dp_ecyl,
&entry->ent.dp_ehd, &entry->ent.dp_esect);
if (compat_aliases) {
idx = 5;
LIST_FOREACH(iter, &basetable->gpt_entry, gpe_entry)
idx++;
entry->ebr_compat_idx = idx;
}
return (ebr_parse_type(gpp->gpp_type, &entry->ent.dp_typ));
}
static void
g_part_ebr_add_alias(struct g_part_table *table, struct g_provider *pp,
struct g_part_entry *baseentry, const char *pfx)
{
struct g_part_ebr_entry *entry;
g_provider_add_alias(pp, "%s%s" EBRNAMFMT, pfx, g_part_separator,
baseentry->gpe_index);
if (compat_aliases) {
entry = (struct g_part_ebr_entry *)baseentry;
g_provider_add_alias(pp, "%.*s%u", (int)strlen(pfx) - 1, pfx,
entry->ebr_compat_idx);
}
}
static struct g_provider *
g_part_ebr_new_provider(struct g_part_table *table, struct g_geom *gp,
struct g_part_entry *baseentry, const char *pfx)
{
struct g_part_ebr_entry *entry;
struct g_provider *pp;
pp = g_new_providerf(gp, "%s%s" EBRNAMFMT, pfx, g_part_separator,
baseentry->gpe_index);
if (compat_aliases) {
entry = (struct g_part_ebr_entry *)baseentry;
g_provider_add_alias(pp, "%.*s%u", (int)strlen(pfx) - 1, pfx,
entry->ebr_compat_idx);
}
return (pp);
}
static int
g_part_ebr_create(struct g_part_table *basetable, struct g_part_parms *gpp)
{
@ -358,24 +406,6 @@ g_part_ebr_dumpto(struct g_part_table *table, struct g_part_entry *baseentry)
entry->ent.dp_typ == DOSPTYP_LINSWP) ? 1 : 0);
}
#if defined(GEOM_PART_EBR_COMPAT)
static void
g_part_ebr_fullname(struct g_part_table *table, struct g_part_entry *entry,
struct sbuf *sb, const char *pfx)
{
struct g_part_entry *iter;
u_int idx;
idx = 5;
LIST_FOREACH(iter, &table->gpt_entry, gpe_entry) {
if (iter == entry)
break;
idx++;
}
sbuf_printf(sb, "%.*s%u", (int)strlen(pfx) - 1, pfx, idx);
}
#endif
static int
g_part_ebr_modify(struct g_part_table *basetable,
struct g_part_entry *baseentry, struct g_part_parms *gpp)
@ -409,8 +439,7 @@ static const char *
g_part_ebr_name(struct g_part_table *table, struct g_part_entry *entry,
char *buf, size_t bufsz)
{
snprintf(buf, bufsz, "+%08u", entry->gpe_index);
snprintf(buf, bufsz, EBRNAMFMT, entry->gpe_index);
return (buf);
}
@ -418,11 +447,6 @@ static int
g_part_ebr_precheck(struct g_part_table *table, enum g_part_ctl req,
struct g_part_parms *gpp)
{
#if defined(GEOM_PART_EBR_COMPAT)
if (req == G_PART_CTL_DESTROY)
return (0);
return (ECANCELED);
#else
/*
* The index is a function of the start of the partition.
* This is not something the user can override, nor is it
@ -432,7 +456,6 @@ g_part_ebr_precheck(struct g_part_table *table, enum g_part_ctl req,
if (req == G_PART_CTL_ADD)
gpp->gpp_index = (gpp->gpp_start / table->gpt_sectors) + 1;
return (0);
#endif
}
static int
@ -501,9 +524,10 @@ g_part_ebr_read(struct g_part_table *basetable, struct g_consumer *cp)
struct g_part_ebr_entry *entry;
u_char *buf;
off_t ofs, msize;
u_int lba;
u_int lba, idx;
int error, index;
idx = 5;
pp = cp->provider;
table = (struct g_part_ebr_table *)basetable;
msize = MIN(pp->mediasize / pp->sectorsize, UINT32_MAX);
@ -525,18 +549,21 @@ g_part_ebr_read(struct g_part_table *basetable, struct g_consumer *cp)
printf("GEOM: %s: invalid entries in the EBR ignored.\n",
pp->name);
}
#ifndef GEOM_PART_EBR_COMPAT
/* Save the first EBR, it can contain a boot code */
/*
* Preserve EBR, it can contain boot code or other metadata we
* are ignorant of.
*/
if (lba == 0)
bcopy(buf, table->ebr, sizeof(table->ebr));
#endif
g_free(buf);
memcpy(table->lba0_ebr, buf, sizeof(table->lba0_ebr));
if (ent[0].dp_typ == 0)
if (ent[0].dp_typ == 0) {
g_free(buf);
break;
}
if (ent[0].dp_typ == 5 && ent[1].dp_typ == 0) {
lba = ent[0].dp_start;
g_free(buf);
continue;
}
@ -547,6 +574,10 @@ g_part_ebr_read(struct g_part_table *basetable, struct g_consumer *cp)
pp->sectorsize;
entry = (struct g_part_ebr_entry *)baseentry;
entry->ent = ent[0];
memcpy(entry->ebr, buf, sizeof(entry->ebr));
if (compat_aliases)
entry->ebr_compat_idx = idx++;
g_free(buf);
if (ent[1].dp_typ == 0)
break;
@ -618,9 +649,7 @@ g_part_ebr_type(struct g_part_table *basetable, struct g_part_entry *baseentry,
static int
g_part_ebr_write(struct g_part_table *basetable, struct g_consumer *cp)
{
#ifndef GEOM_PART_EBR_COMPAT
struct g_part_ebr_table *table;
#endif
struct g_provider *pp;
struct g_part_entry *baseentry, *next;
struct g_part_ebr_entry *entry;
@ -630,10 +659,10 @@ g_part_ebr_write(struct g_part_table *basetable, struct g_consumer *cp)
pp = cp->provider;
buf = g_malloc(pp->sectorsize, M_WAITOK | M_ZERO);
#ifndef GEOM_PART_EBR_COMPAT
table = (struct g_part_ebr_table *)basetable;
bcopy(table->ebr, buf, DOSPARTOFF);
#endif
_Static_assert(DOSPARTOFF <= sizeof(table->lba0_ebr), "");
memcpy(buf, table->lba0_ebr, DOSPARTOFF);
le16enc(buf + DOSMAGICOFFSET, DOSMAGIC);
baseentry = LIST_FIRST(&basetable->gpt_entry);
@ -661,6 +690,9 @@ g_part_ebr_write(struct g_part_table *basetable, struct g_consumer *cp)
do {
entry = (struct g_part_ebr_entry *)baseentry;
_Static_assert(DOSPARTOFF <= sizeof(entry->ebr), "");
memcpy(buf, entry->ebr, DOSPARTOFF);
p = buf + DOSPARTOFF;
p[0] = entry->ent.dp_flag;
p[1] = entry->ent.dp_shd;
@ -686,10 +718,6 @@ g_part_ebr_write(struct g_part_table *basetable, struct g_consumer *cp)
error = g_write_data(cp, baseentry->gpe_start * pp->sectorsize,
buf, pp->sectorsize);
#ifndef GEOM_PART_EBR_COMPAT
if (baseentry->gpe_start == 0)
bzero(buf, DOSPARTOFF);
#endif
baseentry = next;
} while (!error && baseentry != NULL);

1
sys/i386/conf/DEFAULTS
View File

@ -19,7 +19,6 @@ device uart_ns8250
# Default partitioning schemes
options GEOM_PART_BSD
options GEOM_PART_EBR
options GEOM_PART_EBR_COMPAT
options GEOM_PART_MBR
options GEOM_PART_GPT