From b25606806096b51e9d920f50b9bb47773641644d Mon Sep 17 00:00:00 2001 From: Robbie Harwood Date: Thu, 6 Jan 2022 17:42:54 +0000 Subject: [PATCH] btrfs: use full bootloader area Signed-off-by: Robbie Harwood --- ...btrfs-Use-full-btrfs-bootloader-area.patch | 163 ++++++++++++++++++ grub.patches | 1 + grub2.spec | 5 +- 3 files changed, 168 insertions(+), 1 deletion(-) create mode 100644 0213-fs-btrfs-Use-full-btrfs-bootloader-area.patch diff --git a/0213-fs-btrfs-Use-full-btrfs-bootloader-area.patch b/0213-fs-btrfs-Use-full-btrfs-bootloader-area.patch new file mode 100644 index 0000000..a5a62ee --- /dev/null +++ b/0213-fs-btrfs-Use-full-btrfs-bootloader-area.patch @@ -0,0 +1,163 @@ +From 6e5b9bc2f1d2e3a10096716350fa67f48c199f5d Mon Sep 17 00:00:00 2001 +From: Michael Chang +Date: Mon, 13 Dec 2021 14:25:49 +0800 +Subject: [PATCH] fs/btrfs: Use full btrfs bootloader area + +Up to now GRUB can only embed to the first 64 KiB before primary +superblock of btrfs, effectively limiting the GRUB core size. That +could consequently pose restrictions to feature enablement like +advanced zstd compression. + +This patch attempts to utilize full unused area reserved by btrfs for +the bootloader outlined in the document [1]: + + The first 1MiB on each device is unused with the exception of primary + superblock that is on the offset 64KiB and spans 4KiB. + +Apart from that, adjacent sectors to superblock and first block group +are not used for embedding in case of overflow and logged access to +adjacent sectors could be useful for tracing it up. + +This patch has been tested to provide out of the box support for btrfs +zstd compression with which GRUB has been installed to the partition. + +[1] https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs(5)#BOOTLOADER_SUPPORT + +Signed-off-by: Michael Chang +Reviewed-by: Daniel Kiper +(cherry picked from commit b0f06a81c6f31b6fa20be67a96b6683bba8210c9) +--- + grub-core/fs/btrfs.c | 90 +++++++++++++++++++++++++++++++++++++------- + include/grub/disk.h | 2 + + 2 files changed, 79 insertions(+), 13 deletions(-) + +diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c +index 4cc86e9b7..07c0ff874 100644 +--- a/grub-core/fs/btrfs.c ++++ b/grub-core/fs/btrfs.c +@@ -2476,6 +2476,33 @@ grub_btrfs_label (grub_device_t device, char **label) + } + + #ifdef GRUB_UTIL ++ ++struct embed_region { ++ unsigned int start; ++ unsigned int secs; ++}; ++ ++/* ++ * https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs(5)#BOOTLOADER_SUPPORT ++ * The first 1 MiB on each device is unused with the exception of primary ++ * superblock that is on the offset 64 KiB and spans 4 KiB. ++ */ ++ ++static const struct { ++ struct embed_region available; ++ struct embed_region used[6]; ++} btrfs_head = { ++ .available = {0, GRUB_DISK_KiB_TO_SECTORS (1024)}, /* The first 1 MiB. */ ++ .used = { ++ {0, 1}, /* boot.S. */ ++ {GRUB_DISK_KiB_TO_SECTORS (64) - 1, 1}, /* Overflow guard. */ ++ {GRUB_DISK_KiB_TO_SECTORS (64), GRUB_DISK_KiB_TO_SECTORS (4)}, /* 4 KiB superblock. */ ++ {GRUB_DISK_KiB_TO_SECTORS (68), 1}, /* Overflow guard. */ ++ {GRUB_DISK_KiB_TO_SECTORS (1024) - 1, 1}, /* Overflow guard. */ ++ {0, 0} /* Array terminator. */ ++ } ++}; ++ + static grub_err_t + grub_btrfs_embed (grub_device_t device __attribute__ ((unused)), + unsigned int *nsectors, +@@ -2483,25 +2510,62 @@ grub_btrfs_embed (grub_device_t device __attribute__ ((unused)), + grub_embed_type_t embed_type, + grub_disk_addr_t **sectors) + { +- unsigned i; ++ unsigned int i, j, n = 0; ++ const struct embed_region *u; ++ grub_disk_addr_t *map; + + if (embed_type != GRUB_EMBED_PCBIOS) + return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, + "BtrFS currently supports only PC-BIOS embedding"); + +- if (64 * 2 - 1 < *nsectors) +- return grub_error (GRUB_ERR_OUT_OF_RANGE, +- N_("your core.img is unusually large. " +- "It won't fit in the embedding area")); +- +- *nsectors = 64 * 2 - 1; +- if (*nsectors > max_nsectors) +- *nsectors = max_nsectors; +- *sectors = grub_calloc (*nsectors, sizeof (**sectors)); +- if (!*sectors) ++ map = grub_calloc (btrfs_head.available.secs, sizeof (*map)); ++ if (map == NULL) + return grub_errno; +- for (i = 0; i < *nsectors; i++) +- (*sectors)[i] = i + 1; ++ ++ /* ++ * Populating the map array so that it can be used to index if a disk ++ * address is available to embed: ++ * - 0: available, ++ * - 1: unavailable. ++ */ ++ for (u = btrfs_head.used; u->secs; ++u) ++ { ++ unsigned int end = u->start + u->secs; ++ ++ if (end > btrfs_head.available.secs) ++ end = btrfs_head.available.secs; ++ for (i = u->start; i < end; ++i) ++ map[i] = 1; ++ } ++ ++ /* Adding up n until it matches total size of available embedding area. */ ++ for (i = 0; i < btrfs_head.available.secs; ++i) ++ if (map[i] == 0) ++ n++; ++ ++ if (n < *nsectors) ++ { ++ grub_free (map); ++ return grub_error (GRUB_ERR_OUT_OF_RANGE, ++ N_("your core.img is unusually large. " ++ "It won't fit in the embedding area")); ++ } ++ ++ if (n > max_nsectors) ++ n = max_nsectors; ++ ++ /* ++ * Populating the array so that it can used to index disk block address for ++ * an image file's offset to be embedded on disk (the unit is in sectors): ++ * - i: The disk block address relative to btrfs_head.available.start, ++ * - j: The offset in image file. ++ */ ++ for (i = 0, j = 0; i < btrfs_head.available.secs && j < n; ++i) ++ if (map[i] == 0) ++ map[j++] = btrfs_head.available.start + i; ++ ++ *nsectors = n; ++ *sectors = map; + + return GRUB_ERR_NONE; + } +diff --git a/include/grub/disk.h b/include/grub/disk.h +index f95aca929..06210a704 100644 +--- a/include/grub/disk.h ++++ b/include/grub/disk.h +@@ -182,6 +182,8 @@ typedef struct grub_disk_memberlist *grub_disk_memberlist_t; + /* Return value of grub_disk_native_sectors() in case disk size is unknown. */ + #define GRUB_DISK_SIZE_UNKNOWN 0xffffffffffffffffULL + ++#define GRUB_DISK_KiB_TO_SECTORS(x) ((x) << (10 - GRUB_DISK_SECTOR_BITS)) ++ + /* Convert sector number from one sector size to another. */ + static inline grub_disk_addr_t + grub_convert_sector (grub_disk_addr_t sector, +-- +2.34.1 + diff --git a/grub.patches b/grub.patches index b833690..bbb454a 100644 --- a/grub.patches +++ b/grub.patches @@ -210,3 +210,4 @@ Patch0209: 0209-fs-xfs-Fix-unreadable-filesystem-with-v4-superblock.patch Patch0210: 0210-Print-module-name-on-license-check-failure.patch Patch0211: 0211-powerpc-ieee1275-load-grub-at-4MB-not-2MB.patch Patch0212: 0212-grub-mkconfig-restore-umask-for-grub.cfg.patch +Patch0213: 0213-fs-btrfs-Use-full-btrfs-bootloader-area.patch diff --git a/grub2.spec b/grub2.spec index 586a833..7f22435 100644 --- a/grub2.spec +++ b/grub2.spec @@ -14,7 +14,7 @@ Name: grub2 Epoch: 1 Version: 2.06 -Release: 11%{?dist} +Release: 12%{?dist} Summary: Bootloader with support for Linux, Multiboot and more License: GPLv3+ URL: http://www.gnu.org/software/grub/ @@ -523,6 +523,9 @@ mv ${EFI_HOME}/grub.cfg.stb ${EFI_HOME}/grub.cfg %endif %changelog +* Thu Jan 06 2022 Robbie Harwood - 2.06-12 +- btrfs: use full bootloader area + * Fri Dec 10 2021 Robbie Harwood - 2.06-11 - Bump to rerun signing (no code changes)