Date: Sun, 12 Apr 2026 22:17:11 +0000 From: Warner Losh <imp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 890adccde076 - stable/14 - gpart: More nuance for GPT support Message-ID: <69dc19e7.21398.512d0c97@gitrepo.freebsd.org>
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The branch stable/14 has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=890adccde0763536189cc1995e49f753e8d00497 commit 890adccde0763536189cc1995e49f753e8d00497 Author: Warner Losh <imp@FreeBSD.org> AuthorDate: 2024-10-15 23:15:17 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2026-04-12 22:08:16 +0000 gpart: More nuance for GPT support A careful reading of the GPT standard shows that one may have fewer than 128 entries in your GPT table. While the standard requires that we reserve enough space (32 512-byte-LBAs or 4 4096-byte-LBAs), it also explicitly allows one to specify fewer actual partitions (since that controls what is in the CRC). It requires that the first LBA to be 32 (512 sectors) or 6 (4k sectors) or larger. That requirement is not enforced (it's not listed as one of validation criteria for the GPT). We should likely do so in the future. To that end, allow a default number of entries to use (defent) on creation to be different (larger) than the minimum number of legal entries. For gpt, these numbers work out to 128 and 1 respectively. For all the others, make minent == defent so this is a nop for those partitioning schemes. Sponsored by: Netflix Reviewed by: zlei, emaste Differential Revision: https://reviews.freebsd.org/D42246 (cherry picked from commit 09c999b1557a8031d2b60435d71a0a5ed4f0f016) --- sys/geom/part/g_part.c | 2 +- sys/geom/part/g_part.h | 5 +++-- sys/geom/part/g_part_apm.c | 1 + sys/geom/part/g_part_bsd.c | 1 + sys/geom/part/g_part_bsd64.c | 1 + sys/geom/part/g_part_ebr.c | 1 + sys/geom/part/g_part_gpt.c | 3 ++- sys/geom/part/g_part_mbr.c | 1 + 8 files changed, 11 insertions(+), 4 deletions(-) diff --git a/sys/geom/part/g_part.c b/sys/geom/part/g_part.c index 10305ee940fe..02c550d74620 100644 --- a/sys/geom/part/g_part.c +++ b/sys/geom/part/g_part.c @@ -1006,7 +1006,7 @@ g_part_ctl_create(struct gctl_req *req, struct g_part_parms *gpp) table->gpt_gp = gp; table->gpt_scheme = gpp->gpp_scheme; table->gpt_entries = (gpp->gpp_parms & G_PART_PARM_ENTRIES) ? - gpp->gpp_entries : scheme->gps_minent; + gpp->gpp_entries : scheme->gps_defent; LIST_INIT(&table->gpt_entry); if (null == NULL) { cp = g_new_consumer(gp); diff --git a/sys/geom/part/g_part.h b/sys/geom/part/g_part.h index 13bbb1e4126a..575d97623e9b 100644 --- a/sys/geom/part/g_part.h +++ b/sys/geom/part/g_part.h @@ -118,8 +118,9 @@ const char *g_part_alias_name(enum g_part_alias); struct g_part_scheme { KOBJ_CLASS_FIELDS; size_t gps_entrysz; - int gps_minent; - int gps_maxent; + int gps_minent; /* Minimum number of entries possible */ + int gps_defent; /* Default number of entries to create */ + int gps_maxent; /* Maximum number of entries possible */ int gps_bootcodesz; TAILQ_ENTRY(g_part_scheme) scheme_list; }; diff --git a/sys/geom/part/g_part_apm.c b/sys/geom/part/g_part_apm.c index 9ee48168b1e8..5f9cb64eab02 100644 --- a/sys/geom/part/g_part_apm.c +++ b/sys/geom/part/g_part_apm.c @@ -102,6 +102,7 @@ static struct g_part_scheme g_part_apm_scheme = { sizeof(struct g_part_apm_table), .gps_entrysz = sizeof(struct g_part_apm_entry), .gps_minent = 16, + .gps_defent = 16, .gps_maxent = 4096, }; G_PART_SCHEME_DECLARE(g_part_apm); diff --git a/sys/geom/part/g_part_bsd.c b/sys/geom/part/g_part_bsd.c index 625cdb4c727e..d1bee3f6c5e9 100644 --- a/sys/geom/part/g_part_bsd.c +++ b/sys/geom/part/g_part_bsd.c @@ -107,6 +107,7 @@ static struct g_part_scheme g_part_bsd_scheme = { sizeof(struct g_part_bsd_table), .gps_entrysz = sizeof(struct g_part_bsd_entry), .gps_minent = 8, + .gps_defent = 8, .gps_maxent = 20, /* Only 22 entries fit in 512 byte sectors */ .gps_bootcodesz = BBSIZE, }; diff --git a/sys/geom/part/g_part_bsd64.c b/sys/geom/part/g_part_bsd64.c index 4a1481f97c3e..14f8d0cde476 100644 --- a/sys/geom/part/g_part_bsd64.c +++ b/sys/geom/part/g_part_bsd64.c @@ -161,6 +161,7 @@ static struct g_part_scheme g_part_bsd64_scheme = { sizeof(struct g_part_bsd64_table), .gps_entrysz = sizeof(struct g_part_bsd64_entry), .gps_minent = MAXPARTITIONS64, + .gps_defent = MAXPARTITIONS64, .gps_maxent = MAXPARTITIONS64 }; G_PART_SCHEME_DECLARE(g_part_bsd64); diff --git a/sys/geom/part/g_part_ebr.c b/sys/geom/part/g_part_ebr.c index 6be64f58287c..9c1a46111b16 100644 --- a/sys/geom/part/g_part_ebr.c +++ b/sys/geom/part/g_part_ebr.c @@ -125,6 +125,7 @@ static struct g_part_scheme g_part_ebr_scheme = { sizeof(struct g_part_ebr_table), .gps_entrysz = sizeof(struct g_part_ebr_entry), .gps_minent = 1, + .gps_defent = 1, .gps_maxent = INT_MAX, }; G_PART_SCHEME_DECLARE(g_part_ebr); diff --git a/sys/geom/part/g_part_gpt.c b/sys/geom/part/g_part_gpt.c index d795ccf4332b..de22d385af41 100644 --- a/sys/geom/part/g_part_gpt.c +++ b/sys/geom/part/g_part_gpt.c @@ -155,7 +155,8 @@ static struct g_part_scheme g_part_gpt_scheme = { g_part_gpt_methods, sizeof(struct g_part_gpt_table), .gps_entrysz = sizeof(struct g_part_gpt_entry), - .gps_minent = 128, + .gps_minent = 1, + .gps_defent = 128, .gps_maxent = 4096, .gps_bootcodesz = MBRSIZE, }; diff --git a/sys/geom/part/g_part_mbr.c b/sys/geom/part/g_part_mbr.c index 36862c8ff018..e0e764bbaae9 100644 --- a/sys/geom/part/g_part_mbr.c +++ b/sys/geom/part/g_part_mbr.c @@ -116,6 +116,7 @@ static struct g_part_scheme g_part_mbr_scheme = { sizeof(struct g_part_mbr_table), .gps_entrysz = sizeof(struct g_part_mbr_entry), .gps_minent = NDOSPART, + .gps_defent = NDOSPART, .gps_maxent = NDOSPART, .gps_bootcodesz = MBRSIZE, };home | help
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