Add PARTUUID detection support

PATCH Superseded Nicholas Vinson 2 participants 14 messages Apr 7, 2018 – Apr 17, 2018

Share & tools

Nicholas Vinson

author

2018-04-07 23:28 UTC #0 lore raw

v9 cover Add PARTUUID detection support

Changes from Patch v8:
- Renamed GRUB_ENABLE_LINUX_PARTUUID to GRUB_DISABLE_LINUX_PARTUUID
- Updated the 10_linux logic so GRUB_ENABLE_LINUX_PARTUUID and GRUB_ENABLE_LINUX_UUID would behave more independently.
- Documented interactions of GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection in commit message.
- Added optional patch that sets GRUB_DISABLE_LINUX_PARTUUID to true by default.
- Fixed merge conflicts between this patchset and upstream's master branch.

Changes from Patch v7:
- Changed checks in probe_partuuid() to use the variable 'p' instead of disk->partition
- Moved 'disk->partition = p;' assignment to inside the 'p & p->parent == NULL' statement
- Moved 'disk->partition = p->parent;' assignment to before partmap name checks.
- Fixed formatting issues.
- Copied Daniel Kiper's reviewed-by line to unaltered patches.

Changes from Patch v6:
- Corrected spelling and grammatical errors in description text for GRUB_ENABLE_LINUX_PARTUUID
- Moved disk->partition save & restore logic to beginning and end of probe_partuuid()
- Fixed formatting errors in probe_partuuid

Changes from Patch v5:
- Added sign-off by lines
- Fixed formatting errors found by Daniel Kiper

Changes from Patch v4:
- Updated grub.texi to reflect new behavior for GRUB_ENABLE_LINUX_PARTUUID

- Updated 10_linux.in logic to favor the PARTUUID when GRUB_ENABLE_LINUX_PARTUUID is enabled and GRUB_DISABLE_LINUX_UUID is disabled.

Changes from Patch v3:
- Removed flex-2.6.3 compatibility patch

- Removed Steve Kenton's patch

Changes from Patch v2:
- Added flex-2.6.3 compatibility patch

- Fixed a GPT partition read error

- Added Steve Kenton's patch

- Changed struct grub_part_gpt_type name to struct grub_part_gpt_part_guid

- Changed grub_part_gpt_type_t typedef name to grub_part_gpt_guid_t

- Added sprint_gpt_guid to Steve Kenton's patch

- Updated v1 and Steve Kenton's patch to use similar methods when reading partition GUIDs.

Changes from Patch v1:
- Added GRUB_ENABLE_LINUX_PARTUUID variable description to grub.texi

- Removed added gpt_part_guid copy logic from
grub_gpt_partition_map_iterate()

- Removed added NT disk signature copy logic from grub_partition_msdos_iterate()

- Removed modifications to partition number increment logic

- Removed added guid union definition.

- Added GRUB_ENABLE_LINUX_PARTUUID to grub-mkconfig.in export list

- Moved PRINT_GPT_PARTTYPE printing logic to print_gpt_guid() function in grub-probe.c

- Updated PRINT_GPT_PARTTYPE case to call print_gpt_guid() function in grub-probe.c.

- Created probe_partuuid() function in grub-probe.c

- Updated print == PRINT_PARTUUID check logic in probe() to call probe_partuuid().

- Updated UUID logic in 10_linux.in to enable root=PARTUUID feature only if GRUB_DISABLE_LINUX_UUID is not set to true, and GRUB_DEVICE_PARTUUID is not empty, GRUB_ENABLE_LINUX_PARTUUID is set to true.

Hello,

This is a request to add PARTUUID detection support grub-probe for MBR and GPT partition schemes. The Linux kernel supports mounting the root filesystem by Linux device name or by the Partition [GU]UID. GRUB's mkconfig, however, currently only supports specifying the rootfs in the kernel command-line by Linux device name unless an initramfs is also present. When an initramfs is present GRUB's mkconfig will set the kernel's root parameter value to either the Linux device name or to the filesystem [GU]UID.

Therefore, the only way to protect a Linux system from failing to boot when its Linux storage device names change is to either manually edit grub.cfg or /etc/default/grub and append root=PARTUUID=xxx to the command-line or create an initramfs that understands how to mount devices by filesystem [G]UID and let grub-mkconfig pass the filesystem [GU]UID to the initramfs.

The goal of this patch set is to enable root=PARTUUID=xxx support in grub-mkconfig, so that users don't have to manually edit /etc/default/grub or grub.cfg, or create an initramfs for the sole purpose of having a robust bootloader configuration for Linux.

Thanks,
Nicholas Vinson

Nicholas Vinson (5):
Centralize guid prints
Update grub_gpt_partentry
Add PARTUUID detection support to grub-probe
Update grub script template files
Default to disabling partition UUID support

 docs/grub.texi               | 11 +++++++
 grub-core/disk/ldm.c         |  2 +-
 grub-core/partmap/gpt.c      |  4 +--
 include/grub/gpt_partition.h |  8 ++---
 util/grub-install.c          |  2 +-
 util/grub-mkconfig.in        |  3 ++
 util/grub-probe.c            | 76 +++++++++++++++++++++++++++++++++++---------
 util/grub.d/10_linux.in      | 22 +++++++++++--
 8 files changed, 102 insertions(+), 26 deletions(-)

Signature · 1 line

2.16.3

Nicholas Vinson

author

2018-04-07 23:28 UTC #1 lore raw

PATCH v9 1/5 Centralize guid prints

Define print_gpt_guid(), so there is a central function for printing GUID strings. This change is a precursor for later patches which rely on this logic.

Signed-off-by Nicholas Vinson <[email protected]>

Reviewed-by Daniel Kiper <[email protected]>

---
 util/grub-probe.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

util/grub-probe.c +15 ~~-15~~

index 8ac527d2f..21cb80fbe 100644
@@ -129,6 +129,20 @@ get_targets_string (void)
   return str;
 }
 
+static int
+print_gpt_guid (grub_gpt_part_guid_t guid)
+{
+  guid.data1 = grub_le_to_cpu32 (guid.data1);
+  guid.data2 = grub_le_to_cpu16 (guid.data2);
+  guid.data3 = grub_le_to_cpu16 (guid.data3);
+
+  return grub_printf ("%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+		      guid.data1, guid.data2, guid.data3, guid.data4[0],
+		      guid.data4[1], guid.data4[2], guid.data4[3],
+		      guid.data4[4], guid.data4[5], guid.data4[6],
+		      guid.data4[7]);
+}
+
 static void
 do_print (const char *x, void *data)
 {

@@ -641,21 +655,7 @@ probe (const char *path, char **device_names, char delim)
 
               if (grub_disk_read (dev->disk, p->offset, p->index,
                                   sizeof (gptdata), &gptdata) == 0)
-                {
-                  grub_gpt_part_type_t gpttype;
-                  gpttype.data1 = grub_le_to_cpu32 (gptdata.type.data1);
-                  gpttype.data2 = grub_le_to_cpu16 (gptdata.type.data2);
-                  gpttype.data3 = grub_le_to_cpu16 (gptdata.type.data3);
-                  grub_memcpy (gpttype.data4, gptdata.type.data4, 8);
-
-                  grub_printf ("%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
-                               gpttype.data1, gpttype.data2,
-                               gpttype.data3, gpttype.data4[0], 
-                               gpttype.data4[1], gpttype.data4[2],
-                               gpttype.data4[3], gpttype.data4[4],
-                               gpttype.data4[5], gpttype.data4[6],
-                               gpttype.data4[7]);
-                }
+		print_gpt_guid(gptdata.type);
               dev->disk->partition = p;
             }
           putchar (delim);

Signature · 1 line

2.16.3

Nicholas Vinson

author

2018-04-07 23:28 UTC #2 lore raw

PATCH v9 2/5 Update grub_gpt_partentry

In reply to Nicholas Vinson

Rename grub_gpt_part_type to grub_gpt_part_guid and update grub_gpt_partentry to use this type for both the partition type GUID string and the partition GUID string entries. This change ensures that the two GUID fields are handled more consistently and helps to simplify the changes needed to add Linux partition GUID support.

Signed-off-by Nicholas Vinson <[email protected]>

---
 grub-core/disk/ldm.c         | 2 +-
 grub-core/partmap/gpt.c      | 4 ++--
 include/grub/gpt_partition.h | 8 ++++----
 util/grub-install.c          | 2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

grub-core/disk/ldm.c +1 -1

index 0f978ad05..2a22d2d6c 100644
@@ -135,7 +135,7 @@ msdos_has_ldm_partition (grub_disk_t dsk)
   return has_ldm;
 }
 
-static const grub_gpt_part_type_t ldm_type = GRUB_GPT_PARTITION_TYPE_LDM;
+static const grub_gpt_part_guid_t ldm_type = GRUB_GPT_PARTITION_TYPE_LDM;
 
 /* Helper for gpt_ldm_sector.  */
 static int

grub-core/partmap/gpt.c +2 -2

index 83bcba779..103f6796f 100644
@@ -33,10 +33,10 @@ static grub_uint8_t grub_gpt_magic[8] =
     0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
   };
 
-static const grub_gpt_part_type_t grub_gpt_partition_type_empty = GRUB_GPT_PARTITION_TYPE_EMPTY;
+static const grub_gpt_part_guid_t grub_gpt_partition_type_empty = GRUB_GPT_PARTITION_TYPE_EMPTY;
 
 #ifdef GRUB_UTIL
-static const grub_gpt_part_type_t grub_gpt_partition_type_bios_boot = GRUB_GPT_PARTITION_TYPE_BIOS_BOOT;
+static const grub_gpt_part_guid_t grub_gpt_partition_type_bios_boot = GRUB_GPT_PARTITION_TYPE_BIOS_BOOT;
 #endif
 
 /* 512 << 7 = 65536 byte sectors.  */

include/grub/gpt_partition.h +4 -4

index 9668a68c3..7a93f4329 100644
@@ -22,14 +22,14 @@
 #include <grub/types.h>
 #include <grub/partition.h>
 
-struct grub_gpt_part_type
+struct grub_gpt_part_guid
 {
   grub_uint32_t data1;
   grub_uint16_t data2;
   grub_uint16_t data3;
   grub_uint8_t data4[8];
 } GRUB_PACKED;
-typedef struct grub_gpt_part_type grub_gpt_part_type_t;
+typedef struct grub_gpt_part_guid grub_gpt_part_guid_t;
 
 #define GRUB_GPT_PARTITION_TYPE_EMPTY \
   { 0x0, 0x0, 0x0, \

@@ -70,8 +70,8 @@ struct grub_gpt_header
 
 struct grub_gpt_partentry
 {
-  grub_gpt_part_type_t type;
-  grub_uint8_t guid[16];
+  grub_gpt_part_guid_t type;
+  grub_gpt_part_guid_t guid;
   grub_uint64_t start;
   grub_uint64_t end;
   grub_uint64_t attrib;

util/grub-install.c +1 -1

index 690f180c5..78d0138cb 100644
@@ -714,7 +714,7 @@ is_prep_partition (grub_device_t dev)
       if (grub_disk_read (dev->disk, p->offset, p->index,
 			  sizeof (gptdata), &gptdata) == 0)
 	{
-	  const grub_gpt_part_type_t template = {
+	  const grub_gpt_part_guid_t template = {
 	    grub_cpu_to_le32_compile_time (0x9e1a2d38),
 	    grub_cpu_to_le16_compile_time (0xc612),
 	    grub_cpu_to_le16_compile_time (0x4316),

Signature · 1 line

2.16.3

Nicholas Vinson

author

2018-04-07 23:28 UTC #3 lore raw

PATCH v9 3/5 Add PARTUUID detection support to grub-probe

In reply to Nicholas Vinson

Add PARTUUID detection support grub-probe for MBR and GPT partition schemes.

Signed-off-by Nicholas Vinson <[email protected]>

Reviewed-by Daniel Kiper <[email protected]>

---
 util/grub-probe.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

util/grub-probe.c +46 -0

index 21cb80fbe..e91ae730e 100644
@@ -28,6 +28,7 @@
 #include <grub/partition.h>
 #include <grub/msdos_partition.h>
 #include <grub/gpt_partition.h>
+#include <grub/i386/pc/boot.h>
 #include <grub/emu/hostdisk.h>
 #include <grub/emu/getroot.h>
 #include <grub/term.h>

@@ -62,6 +63,7 @@ enum {
   PRINT_DRIVE,
   PRINT_DEVICE,
   PRINT_PARTMAP,
+  PRINT_PARTUUID,
   PRINT_ABSTRACTION,
   PRINT_CRYPTODISK_UUID,
   PRINT_HINT_STR,

@@ -85,6 +87,7 @@ static const char *targets[] =
     [PRINT_DRIVE]              = "drive",
     [PRINT_DEVICE]             = "device",
     [PRINT_PARTMAP]            = "partmap",
+    [PRINT_PARTUUID]           = "partuuid",
     [PRINT_ABSTRACTION]        = "abstraction",
     [PRINT_CRYPTODISK_UUID]    = "cryptodisk_uuid",
     [PRINT_HINT_STR]           = "hints_string",

@@ -181,6 +184,43 @@ probe_partmap (grub_disk_t disk, char delim)
     }
 }
 
+static void
+probe_partuuid (grub_disk_t disk, char delim)
+{
+  grub_partition_t p = disk->partition;
+
+  /*
+   * Nested partitions not supported for now.
+   * Non-nested partitions must have disk->partition->parent == NULL
+   */
+  if (p && p->parent == NULL)
+    {
+      disk->partition = p->parent;
+      if (strcmp(p->partmap->name, "msdos") == 0)
+	{
+	    /*
+	     * The partition GUID for MSDOS is the partition number (starting
+	     * with 1) prepended with the NT disk signature.
+	     */
+	    grub_uint32_t nt_disk_sig;
+
+	    if (grub_disk_read (disk, 0, GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC,
+				sizeof(nt_disk_sig), &nt_disk_sig) == 0)
+	      grub_printf ("%08x-%02x",
+			   grub_le_to_cpu32(nt_disk_sig), 1 + p->number);
+	}
+      else if (strcmp(p->partmap->name, "gpt") == 0)
+	{
+	  struct grub_gpt_partentry gptdata;
+
+	  if (grub_disk_read (disk, p->offset, p->index,
+			      sizeof(gptdata), &gptdata) == 0)
+	    print_gpt_guid(gptdata.guid);
+	}
+      disk->partition = p;
+    }
+}
+
 static void
 probe_cryptodisk_uuid (grub_disk_t disk, char delim)
 {

@@ -635,6 +675,12 @@ probe (const char *path, char **device_names, char delim)
 	/* Check if dev->disk itself is contained in a partmap.  */
 	probe_partmap (dev->disk, delim);
 
+      else if (print == PRINT_PARTUUID)
+	{
+	  probe_partuuid (dev->disk, delim);
+	  putchar (delim);
+	}
+
       else if (print == PRINT_MSDOS_PARTTYPE)
 	{
 	  if (dev->disk->partition

Signature · 1 line

2.16.3

Nicholas Vinson

author

2018-04-07 23:28 UTC #4 lore raw

PATCH v9 4/5 Update grub script template files

In reply to Nicholas Vinson

Update grub-mkconfig.in and 10_linux.in to support grub-probe's new partuuid target. Update grub.texi documentation. The following table shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection interact:

Initramfs  GRUB_DISABLE_LINUX_PARTUUID  GRUB_DISABLE_LINUX_UUID  Linux Root
detected   Set                          Set                      ID Method

False      False                        False                    part UUID
False      False                        True                     part UUID
False      True                         False                    dev name
False      True                         True                     dev name
True       False                        False                    fs UUID
True       False                        True                     part UUID
True       True                         False                    fs UUID
True       True                         True                     dev name

Signed-off-by Nicholas Vinson <[email protected]>

---
 docs/grub.texi          | 10 ++++++++++
 util/grub-mkconfig.in   |  3 +++
 util/grub.d/10_linux.in | 18 +++++++++++++++---
 3 files changed, 28 insertions(+), 3 deletions(-)

docs/grub.texi +10 -0

index 65b4bbeda..06f0afe45 100644
@@ -1424,6 +1424,16 @@ the Linux kernel, using a @samp{root=UUID=...} kernel parameter.  This is
 usually more reliable, but in some cases it may not be appropriate.  To
 disable the use of UUIDs, set this option to @samp{true}.
 
+@item GRUB_DISABLE_LINUX_PARTUUID
+If @command{grub-mkconfig} cannot identify the root filesystem via its
+universally-unique indentifier (UUID), @command{grub-mkconfig} will use the UUID
+of the partition containing the filesystem to identify the root filesystem to
+the Linux kernel via a @samp{root=PARTUUID=...} kernel parameter.  This is not
+as reliable as using the filesystem UUID, but is more reliable than using the
+Linux device names.  When enabled, this option requires the Linux kernel version
+to be greater than 2.6.37 (3.10 for systems using the MSDOS partition scheme) or
+newer.  To disable the use of partition UUIDs, set this option to @samp{true}.
+
 @item GRUB_DISABLE_RECOVERY
 If this option is set to @samp{true}, disable the generation of recovery
 mode menu entries.

util/grub-mkconfig.in +3 -0

index 35ef583b0..33332360e 100644
@@ -134,6 +134,7 @@ fi
 # Device containing our userland.  Typically used for root= parameter.
 GRUB_DEVICE="`${grub_probe} --target=device /`"
 GRUB_DEVICE_UUID="`${grub_probe} --device ${GRUB_DEVICE} --target=fs_uuid 2> /dev/null`" || true
+GRUB_DEVICE_PARTUUID="`${grub_probe} --device ${GRUB_DEVICE} --target=partuuid 2> /dev/null`" || true
 
 # Device containing our /boot partition.  Usually the same as GRUB_DEVICE.
 GRUB_DEVICE_BOOT="`${grub_probe} --target=device /boot`"

@@ -188,6 +189,7 @@ if [ "x${GRUB_ACTUAL_DEFAULT}" = "xsaved" ] ; then GRUB_ACTUAL_DEFAULT="`"${grub
 # override them.
 export GRUB_DEVICE \
   GRUB_DEVICE_UUID \
+  GRUB_DEVICE_PARTUUID \
   GRUB_DEVICE_BOOT \
   GRUB_DEVICE_BOOT_UUID \
   GRUB_FS \

@@ -223,6 +225,7 @@ export GRUB_DEFAULT \
   GRUB_TERMINAL_OUTPUT \
   GRUB_SERIAL_COMMAND \
   GRUB_DISABLE_LINUX_UUID \
+  GRUB_DISABLE_LINUX_PARTUUID \
   GRUB_DISABLE_RECOVERY \
   GRUB_VIDEO_BACKEND \
   GRUB_GFXMODE \

util/grub.d/10_linux.in +15 -3

index faedf74e1..6916f1841 100644
@@ -45,10 +45,16 @@ esac
 
 # btrfs may reside on multiple devices. We cannot pass them as value of root= parameter
 # and mounting btrfs requires user space scanning, so force UUID in this case.
-if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
-    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
+if ( [ "x${GRUB_DEVICE_UUID}" = "x" ] && [ "x${GRUB_DEVICE_PARTUUID}" = "x" ) \
+    || ( [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
+	&& [ "x${GRUB_DISABLE_LINUX_PARTUUID}" = "xtrue" ] ) \
+    || ( ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
+	&& ! test -e "/dev/disk/by-partuuid/${GRUB_DEVICE_PARTUUID}" ) \
     || ( test -e "${GRUB_DEVICE}" && uses_abstraction "${GRUB_DEVICE}" lvm ); then
   LINUX_ROOT_DEVICE=${GRUB_DEVICE}
+elif [ "x${GRUB_DEVICE_UUID}" = "x" ] \
+    || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ]; then
+  LINUX_ROOT_DEVICE=PARTUUID=${GRUB_DEVICE_PARTUUID}
 else
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
 fi

@@ -242,7 +248,13 @@ while [ "x$list" != "x" ] ; do
   if test -z "${initramfs}" && test -z "${initrd_real}" ; then
     # "UUID=" and "ZFS=" magic is parsed by initrd or initramfs.  Since there's
     # no initrd or builtin initramfs, it can't work here.
-    linux_root_device_thisversion=${GRUB_DEVICE}
+    if [ "x${GRUB_DEVICE_PARTUUID}" = "x" ] \
+	|| [ "x${GRUB_DISABLE_LINUX_PARTUUID}" = "xtrue" ]; then
+
+	linux_root_device_thisversion=${GRUB_DEVICE}
+    else
+	linux_root_device_thisversion=PARTUUID=${GRUB_DEVICE_PARTUUID}
+    fi
   fi
 
   if [ "x$is_top_level" = xtrue ] && [ "x${GRUB_DISABLE_SUBMENU}" != xy ]; then

Signature · 1 line

2.16.3

Daniel Kiper

2018-04-10 20:52 UTC #5 lore raw

Re: [GRUB PARTUUID PATCH V9 4/5] Update grub script template files

Quoted 8 lines · Nicholas Vinson

Update grub-mkconfig.in and 10_linux.in to support grub-probe's new partuuid target. Update grub.texi documentation. The following table shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection interact:
Initramfs  GRUB_DISABLE_LINUX_PARTUUID  GRUB_DISABLE_LINUX_UUID  Linux Root
detected   Set                          Set                      ID Method

Quoted 8 lines

False      False                        False                    part UUID
False      False                        True                     part UUID
False      True                         False                    dev name
False      True                         True                     dev name
True       False                        False                    fs UUID
True       False                        True                     part UUID
True       True                         False                    fs UUID
True       True                         True                     dev name

What will happen if GRUB_DISABLE_LINUX_PARTUUID and/or GRUB_DISABLE_LINUX_UUID are not set? I think that you can avoid that by setting defaults. You do that for GRUB_DISABLE_LINUX_PARTUUID in next patch but GRUB_DISABLE_LINUX_UUID does not have any default.

Quoted 5 lines

Signed-off-by Nicholas Vinson <[email protected]>

---
 docs/grub.texi          | 10 ++++++++++
 util/grub-mkconfig.in   |  3 +++
 util/grub.d/10_linux.in | 18 +++++++++++++++---

Could you update util/grub.d/20_linux_xen.in too?

Quoted 7 lines

 3 files changed, 28 insertions(+), 3 deletions(-)

docs/grub.texi +0 -0

index 65b4bbeda..06f0afe45 100644

docs/grub.texi the Linux kernel, using a @samp{root=UUID=...} kernel parameter. This is · line 1433

Quoted 10 lines

docs/grub.texi +7 -0

@@ -1424,6 +1424,16 @@ the Linux kernel, using a @samp{root=UUID=...} kernel parameter.  This is
 usually more reliable, but in some cases it may not be appropriate.  To
 disable the use of UUIDs, set this option to @samp{true}.
 
+@item GRUB_DISABLE_LINUX_PARTUUID
+If @command{grub-mkconfig} cannot identify the root filesystem via its
+universally-unique indentifier (UUID), @command{grub-mkconfig} will use the UUID
+of the partition containing the filesystem to identify the root filesystem to
+the Linux kernel via a @samp{root=PARTUUID=...} kernel parameter.  This is not
+as reliable as using the filesystem UUID, but is more reliable than using the
+Linux device names.  When enabled, this option requires the Linux kernel version

s/When enabled, /When enabled, GRUB_DISABLE_LINUX_PARTUUID set to false, / or something like that. Otherwise it is unclear.

Daniel

Nick Vinson

author

2018-04-11 03:00 UTC #6 lore raw

Re: [GRUB PARTUUID PATCH V9 4/5] Update grub script template files

Quoted 18 lines · Daniel Kiper

Quoted 8 lines · Nicholas Vinson

Update grub-mkconfig.in and 10_linux.in to support grub-probe's new partuuid target. Update grub.texi documentation. The following table shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection interact:
Initramfs  GRUB_DISABLE_LINUX_PARTUUID  GRUB_DISABLE_LINUX_UUID  Linux Root
detected   Set                          Set                      ID Method

Quoted 8 lines

False      False                        False                    part UUID
False      False                        True                     part UUID
False      True                         False                    dev name
False      True                         True                     dev name
True       False                        False                    fs UUID
True       False                        True                     part UUID
True       True                         False                    fs UUID
True       True                         True                     dev name

Quoted 5 lines

What will happen if GRUB_DISABLE_LINUX_PARTUUID and/or GRUB_DISABLE_LINUX_UUID are not set? I think that you can avoid that by setting defaults. You do that for GRUB_DISABLE_LINUX_PARTUUID in next patch but GRUB_DISABLE_LINUX_UUID does not have any default.

If they're not set, then that's the same as them being set to 'False'. I should have worded my table above a bit differently and used Yes/No instead of True/False as that is really what it is trying to convey. I.E. If there is no initramfs detected and GRUB_DISABLE_LINUX_PARTUUID is not set and GRUB_DISABLE_LINUX_UUID is not set, set the kernel root variable to "root=PARTUUID=...".

In the scripts, the only value explicitly checked for is 'true'. Anything else (including unset) is considered false.

Quoted 7 lines

Quoted 5 lines
Signed-off-by Nicholas Vinson <[email protected]>
---
 docs/grub.texi          | 10 ++++++++++
 util/grub-mkconfig.in   |  3 +++
 util/grub.d/10_linux.in | 18 +++++++++++++++---
Could you update util/grub.d/20_linux_xen.in too?

Let me see what I can do. I have never worked with xen before, so I do not know much about it.

Quoted 11 lines

 3 files changed, 28 insertions(+), 3 deletions(-)

docs/grub.texi +0 -0

index 65b4bbeda..06f0afe45 100644
@@ -1424,6 +1424,16 @@ the Linux kernel, using a @samp{root=UUID=...} kernel parameter.  This is
 usually more reliable, but in some cases it may not be appropriate.  To
 disable the use of UUIDs, set this option to @samp{true}.

Quoted 10 lines

docs/grub.texi the Linux kernel, using a @samp{root=UUID=...} kernel parameter. This is · line 1433
Quoted 7 lines
docs/grub.texi +7 -0
+@item GRUB_DISABLE_LINUX_PARTUUID
+If @command{grub-mkconfig} cannot identify the root filesystem via its
+universally-unique indentifier (UUID), @command{grub-mkconfig} will use the UUID
+of the partition containing the filesystem to identify the root filesystem to
+the Linux kernel via a @samp{root=PARTUUID=...} kernel parameter.  This is not
+as reliable as using the filesystem UUID, but is more reliable than using the
+Linux device names.  When enabled, this option requires the Linux kernel version
s/When enabled, /When enabled, GRUB_DISABLE_LINUX_PARTUUID set to false, / or something like that. Otherwise it is unclear.

I'll clean up the wording in the next release.

Thanks,
Nicholas Vinson

Quoted 3 lines

Daniel

Daniel Kiper

2018-04-11 08:31 UTC #7 lore raw

Re: [GRUB PARTUUID PATCH V9 4/5] Update grub script template files

Quoted 25 lines · Nick Vinson

Quoted 18 lines · Daniel Kiper
Quoted 8 lines · Nicholas Vinson
Update grub-mkconfig.in and 10_linux.in to support grub-probe's new partuuid target. Update grub.texi documentation. The following table shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection interact:
Initramfs  GRUB_DISABLE_LINUX_PARTUUID  GRUB_DISABLE_LINUX_UUID  Linux Root
detected   Set                          Set                      ID Method
Quoted 8 lines
False      False                        False                    part UUID
False      False                        True                     part UUID
False      True                         False                    dev name
False      True                         True                     dev name
True       False                        False                    fs UUID
True       False                        True                     part UUID
True       True                         False                    fs UUID
True       True                         True                     dev name
Quoted 5 lines
What will happen if GRUB_DISABLE_LINUX_PARTUUID and/or GRUB_DISABLE_LINUX_UUID are not set? I think that you can avoid that by setting defaults. You do that for GRUB_DISABLE_LINUX_PARTUUID in next patch but GRUB_DISABLE_LINUX_UUID does not have any default.

Quoted 3 lines

If they're not set, then that's the same as them being set to 'False'. I should have worded my table above a bit differently and used Yes/No instead of True/False as that is really what it is trying to convey.

IMO it will be more confusing. I think that I would use lowercase false/true as it is used in the script and below the table I would add a note that <VARIABLE_UNSET> == false or something like that.

Quoted 6 lines

I.E. If there is no initramfs detected and GRUB_DISABLE_LINUX_PARTUUID is not set and GRUB_DISABLE_LINUX_UUID is not set, set the kernel root variable to "root=PARTUUID=...".
In the scripts, the only value explicitly checked for is 'true'. Anything else (including unset) is considered false.

OK, perfect!

Quoted 10 lines

Quoted 7 lines
Quoted 5 lines
Signed-off-by Nicholas Vinson <[email protected]>
---
 docs/grub.texi          | 10 ++++++++++
 util/grub-mkconfig.in   |  3 +++
 util/grub.d/10_linux.in | 18 +++++++++++++++---
Could you update util/grub.d/20_linux_xen.in too?
Let me see what I can do. I have never worked with xen before, so I do not know much about it.

This should be easy. However, if you are not sure please drop me a line.

Quoted 21 lines

Quoted 10 lines

 3 files changed, 28 insertions(+), 3 deletions(-)

docs/grub.texi +0 -0

index 65b4bbeda..06f0afe45 100644
@@ -1424,6 +1424,16 @@ the Linux kernel, using a @samp{root=UUID=...} kernel parameter.  This is
 usually more reliable, but in some cases it may not be appropriate.  To
 disable the use of UUIDs, set this option to @samp{true}.

Quoted 10 lines

docs/grub.texi the Linux kernel, using a @samp{root=UUID=...} kernel parameter. This is · line 1433
Quoted 7 lines
docs/grub.texi +7 -0
+@item GRUB_DISABLE_LINUX_PARTUUID
+If @command{grub-mkconfig} cannot identify the root filesystem via its
+universally-unique indentifier (UUID), @command{grub-mkconfig} will use the UUID
+of the partition containing the filesystem to identify the root filesystem to
+the Linux kernel via a @samp{root=PARTUUID=...} kernel parameter.  This is not
+as reliable as using the filesystem UUID, but is more reliable than using the
+Linux device names.  When enabled, this option requires the Linux kernel version
s/When enabled, /When enabled, GRUB_DISABLE_LINUX_PARTUUID set to false, / or something like that. Otherwise it is unclear.

Quoted 1 line

I'll clean up the wording in the next release.

Thanks a lot!

By the way, should not we merge patches 4 and 5 into one patch?

Daniel

Nick Vinson

author

2018-04-11 14:45 UTC #8 lore raw

Re: [GRUB PARTUUID PATCH V9 4/5] Update grub script template files

Quoted 26 lines · Daniel Kiper

Quoted 25 lines · Nick Vinson
Quoted 23 lines · Daniel Kiper
Quoted 8 lines · Nicholas Vinson
Update grub-mkconfig.in and 10_linux.in to support grub-probe's new partuuid target. Update grub.texi documentation. The following table shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection interact:
Initramfs  GRUB_DISABLE_LINUX_PARTUUID  GRUB_DISABLE_LINUX_UUID  Linux Root
detected   Set                          Set                      ID Method
Quoted 8 lines
False      False                        False                    part UUID
False      False                        True                     part UUID
False      True                         False                    dev name
False      True                         True                     dev name
True       False                        False                    fs UUID
True       False                        True                     part UUID
True       True                         False                    fs UUID
True       True                         True                     dev name
What will happen if GRUB_DISABLE_LINUX_PARTUUID and/or GRUB_DISABLE_LINUX_UUID are not set? I think that you can avoid that by setting defaults. You do that for GRUB_DISABLE_LINUX_PARTUUID in next patch but GRUB_DISABLE_LINUX_UUID does not have any default.

Quoted 7 lines

Quoted 3 lines
If they're not set, then that's the same as them being set to 'False'. I should have worded my table above a bit differently and used Yes/No instead of True/False as that is really what it is trying to convey.
IMO it will be more confusing. I think that I would use lowercase false/true as it is used in the script and below the table I would add a note that <VARIABLE_UNSET> == false or something like that.

Ack. I will update the commit comment.

Quoted 44 lines

Quoted 7 lines
I.E. If there is no initramfs detected and GRUB_DISABLE_LINUX_PARTUUID is not set and GRUB_DISABLE_LINUX_UUID is not set, set the kernel root variable to "root=PARTUUID=...".
In the scripts, the only value explicitly checked for is 'true'. Anything else (including unset) is considered false.
OK, perfect!
Quoted 10 lines
Quoted 7 lines
Quoted 5 lines
Signed-off-by Nicholas Vinson <[email protected]>
---
 docs/grub.texi          | 10 ++++++++++
 util/grub-mkconfig.in   |  3 +++
 util/grub.d/10_linux.in | 18 +++++++++++++++---
Could you update util/grub.d/20_linux_xen.in too?
Let me see what I can do. I have never worked with xen before, so I do not know much about it.
This should be easy. However, if you are not sure please drop me a line.
Quoted 21 lines
Quoted 20 lines
Quoted 7 lines
 3 files changed, 28 insertions(+), 3 deletions(-)
docs/grub.texi +0 -0
index 65b4bbeda..06f0afe45 100644
docs/grub.texi the Linux kernel, using a @samp{root=UUID=...} kernel parameter. This is · line 1433
Quoted 10 lines
docs/grub.texi +7 -0
@@ -1424,6 +1424,16 @@ the Linux kernel, using a @samp{root=UUID=...} kernel parameter.  This is
 usually more reliable, but in some cases it may not be appropriate.  To
 disable the use of UUIDs, set this option to @samp{true}.
 
+@item GRUB_DISABLE_LINUX_PARTUUID
+If @command{grub-mkconfig} cannot identify the root filesystem via its
+universally-unique indentifier (UUID), @command{grub-mkconfig} will use the UUID
+of the partition containing the filesystem to identify the root filesystem to
+the Linux kernel via a @samp{root=PARTUUID=...} kernel parameter.  This is not
+as reliable as using the filesystem UUID, but is more reliable than using the
+Linux device names.  When enabled, this option requires the Linux kernel version
s/When enabled, /When enabled, GRUB_DISABLE_LINUX_PARTUUID set to false, / or something like that. Otherwise it is unclear.

Quoted 5 lines

Quoted 1 line
I'll clean up the wording in the next release.
Thanks a lot!
By the way, should not we merge patches 4 and 5 into one patch?

We should.

I split it so that if #5 proved controversial for some reason and received a lot of resistance, it could be dropped and the remainder of the patchset could be merged.

There does not seem to be any issue with setting GRUB_DISABLE_LINUX_PARTUUID to a default value, so there is no reason to keep it separate.

Thanks,
Nicholas Vinson

Quoted 3 lines

Daniel

Daniel Kiper

2018-04-16 11:48 UTC #9 lore raw

Re: [GRUB PARTUUID PATCH V9 4/5] Update grub script template files

Quoted 31 lines · Nick Vinson

Quoted 30 lines · Daniel Kiper
Quoted 28 lines · Nick Vinson
Quoted 18 lines · Daniel Kiper
Quoted 8 lines · Nicholas Vinson
Update grub-mkconfig.in and 10_linux.in to support grub-probe's new partuuid target. Update grub.texi documentation. The following table shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection interact:
Initramfs  GRUB_DISABLE_LINUX_PARTUUID  GRUB_DISABLE_LINUX_UUID  Linux Root
detected   Set                          Set                      ID Method
Quoted 8 lines
False      False                        False                    part UUID
False      False                        True                     part UUID
False      True                         False                    dev name
False      True                         True                     dev name
True       False                        False                    fs UUID
True       False                        True                     part UUID
True       True                         False                    fs UUID
True       True                         True                     dev name
Quoted 5 lines
What will happen if GRUB_DISABLE_LINUX_PARTUUID and/or GRUB_DISABLE_LINUX_UUID are not set? I think that you can avoid that by setting defaults. You do that for GRUB_DISABLE_LINUX_PARTUUID in next patch but GRUB_DISABLE_LINUX_UUID does not have any default.
If they're not set, then that's the same as them being set to 'False'. I should have worded my table above a bit differently and used Yes/No instead of True/False as that is really what it is trying to convey.

Quoted 5 lines

Quoted 3 lines
IMO it will be more confusing. I think that I would use lowercase false/true as it is used in the script and below the table I would add a note that <VARIABLE_UNSET> == false or something like that.
Ack. I will update the commit comment.

Thanks. May I ask you to put similar table into docs/grub.texi?

Daniel

Nick Vinson

author

2018-04-17 05:34 UTC #10 lore raw

Re: [GRUB PARTUUID PATCH V9 4/5] Update grub script template files

Quoted 32 lines · Daniel Kiper

Quoted 31 lines · Nick Vinson
Quoted 30 lines · Daniel Kiper
Quoted 28 lines · Nick Vinson
Quoted 18 lines · Daniel Kiper
Quoted 8 lines · Nicholas Vinson
Update grub-mkconfig.in and 10_linux.in to support grub-probe's new partuuid target. Update grub.texi documentation. The following table shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection interact:
Initramfs  GRUB_DISABLE_LINUX_PARTUUID  GRUB_DISABLE_LINUX_UUID  Linux Root
detected   Set                          Set                      ID Method
Quoted 8 lines
False      False                        False                    part UUID
False      False                        True                     part UUID
False      True                         False                    dev name
False      True                         True                     dev name
True       False                        False                    fs UUID
True       False                        True                     part UUID
True       True                         False                    fs UUID
True       True                         True                     dev name
Quoted 5 lines
What will happen if GRUB_DISABLE_LINUX_PARTUUID and/or GRUB_DISABLE_LINUX_UUID are not set? I think that you can avoid that by setting defaults. You do that for GRUB_DISABLE_LINUX_PARTUUID in next patch but GRUB_DISABLE_LINUX_UUID does not have any default.
If they're not set, then that's the same as them being set to 'False'. I should have worded my table above a bit differently and used Yes/No instead of True/False as that is really what it is trying to convey.

Quoted 7 lines

Quoted 5 lines
Quoted 3 lines
IMO it will be more confusing. I think that I would use lowercase false/true as it is used in the script and below the table I would add a note that <VARIABLE_UNSET> == false or something like that.
Ack. I will update the commit comment.
Thanks. May I ask you to put similar table into docs/grub.texi?

Done.

Thanks,
Nicholas Vinson

Quoted 3 lines

Daniel

Nicholas Vinson

author

2018-04-07 23:28 UTC #11 lore raw

PATCH v9 5/5 Default to disabling partition UUID support

In reply to Nicholas Vinson

The addition of GRUB_DISABLE_LINUX_PARTUUID and having it default to 'false' is a breaking change for systems that use GPT partition schemes and Linux kernel version 2.6.37 or older and a breaking change for systems that use MBR partition schemes and Linux kernel version 3.10 or older.

This patch updates grub.d/10_linux so that GRUB_DISABLE_LINUX_PARTUUID is set to 'true' if the system has not specified otherwise.

Signed-off-by Nicholas Vinson <[email protected]>

---
 docs/grub.texi          | 5 +++--
 util/grub.d/10_linux.in | 4 ++++
 2 files changed, 7 insertions(+), 2 deletions(-)

docs/grub.texi +3 -2

index 06f0afe45..3fcc42e74 100644
@@ -1426,13 +1426,14 @@ disable the use of UUIDs, set this option to @samp{true}.
 
 @item GRUB_DISABLE_LINUX_PARTUUID
 If @command{grub-mkconfig} cannot identify the root filesystem via its
-universally-unique indentifier (UUID), @command{grub-mkconfig} will use the UUID
+universally-unique indentifier (UUID), @command{grub-mkconfig} can use the UUID
 of the partition containing the filesystem to identify the root filesystem to
 the Linux kernel via a @samp{root=PARTUUID=...} kernel parameter.  This is not
 as reliable as using the filesystem UUID, but is more reliable than using the
 Linux device names.  When enabled, this option requires the Linux kernel version
 to be greater than 2.6.37 (3.10 for systems using the MSDOS partition scheme) or
-newer.  To disable the use of partition UUIDs, set this option to @samp{true}.
+newer.  This option defaults to @samp{true}.  To enable the use of partition
+UUIDs, set this option to @samp{false}.
 
 @item GRUB_DISABLE_RECOVERY
 If this option is set to @samp{true}, disable the generation of recovery

util/grub.d/10_linux.in +4 -0

index 6916f1841..146499f22 100644
@@ -43,6 +43,10 @@ case ${GRUB_DEVICE} in
   ;;
 esac
 
+# Default to disabling partition uuid support to maintian compatibility with
+# older kernels.
+GRUB_DISABLE_LINUX_PARTUUID=${GRUB_DISABLE_LINUX_PARTUUID-true}
+
 # btrfs may reside on multiple devices. We cannot pass them as value of root= parameter
 # and mounting btrfs requires user space scanning, so force UUID in this case.
 if ( [ "x${GRUB_DEVICE_UUID}" = "x" ] && [ "x${GRUB_DEVICE_PARTUUID}" = "x" ) \

Signature · 1 line

2.16.3

Daniel Kiper

2018-04-10 20:56 UTC #12 lore raw

In reply to Nicholas Vinson

Quoted 11 lines · Nicholas Vinson

Changes from Patch v8:
- Renamed GRUB_ENABLE_LINUX_PARTUUID to GRUB_DISABLE_LINUX_PARTUUID
- Updated the 10_linux logic so GRUB_ENABLE_LINUX_PARTUUID and GRUB_ENABLE_LINUX_UUID would behave more independently.
- Documented interactions of GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection in commit message.
- Added optional patch that sets GRUB_DISABLE_LINUX_PARTUUID to true by default.
- Fixed merge conflicts between this patchset and upstream's master branch.

Could you provide summary for current version not only for previous ones?

Anyway, I think that most of the patches are now in good shape. I am looking forward for next version.

Thank you for doing the work.

Daniel

Nick Vinson

author

2018-04-11 03:02 UTC #13 lore raw

Quoted 13 lines · Daniel Kiper

Quoted 11 lines · Nicholas Vinson
Changes from Patch v8:
- Renamed GRUB_ENABLE_LINUX_PARTUUID to GRUB_DISABLE_LINUX_PARTUUID
- Updated the 10_linux logic so GRUB_ENABLE_LINUX_PARTUUID and GRUB_ENABLE_LINUX_UUID would behave more independently.
- Documented interactions of GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection in commit message.
- Added optional patch that sets GRUB_DISABLE_LINUX_PARTUUID to true by default.
- Fixed merge conflicts between this patchset and upstream's master branch.

Quoted 1 line

Could you provide summary for current version not only for previous ones?

I can add a summary section before the change log. I'll make sure to do so with the next patchset.

Thanks,
Nicholas Vinson

Quoted 8 lines

Anyway, I think that most of the patches are now in good shape. I am looking forward for next version.
Thank you for doing the work.
Daniel