From 42aba3795c01fff399496be4fbdd5b038ab326140a9c5c221935b368db3e7d3d Mon Sep 17 00:00:00 2001 From: Michael Chang Date: Mon, 6 Dec 2021 02:44:05 +0000 Subject: [PATCH] Accepting request 935870 from home:michael-chang:branches:Base:System - Fix extent not found when initramfs contains shared extents (bsc#1190982) * 0001-fs-btrfs-Make-extent-item-iteration-to-handle-gaps.patch OBS-URL: https://build.opensuse.org/request/show/935870 OBS-URL: https://build.opensuse.org/package/show/Base:System/grub2?expand=0&rev=398 --- ...extent-item-iteration-to-handle-gaps.patch | 124 ++++++++++++++++++ grub2.changes | 6 + grub2.spec | 1 + 3 files changed, 131 insertions(+) create mode 100644 0001-fs-btrfs-Make-extent-item-iteration-to-handle-gaps.patch diff --git a/0001-fs-btrfs-Make-extent-item-iteration-to-handle-gaps.patch b/0001-fs-btrfs-Make-extent-item-iteration-to-handle-gaps.patch new file mode 100644 index 0000000..b7b3fcd --- /dev/null +++ b/0001-fs-btrfs-Make-extent-item-iteration-to-handle-gaps.patch @@ -0,0 +1,124 @@ +From 149df8b7bb86401693e1f064859de0a8906d97b7 Mon Sep 17 00:00:00 2001 +From: Qu Wenruo +Date: Thu, 28 Oct 2021 17:44:57 +0800 +Subject: [PATCH] fs/btrfs: Make extent item iteration to handle gaps + +[BUG] +Grub btrfs implementation can't handle two very basic btrfs file +layouts: + +1. Mixed inline/regualr extents + # mkfs.btrfs -f test.img + # mount test.img /mnt/btrfs + # xfs_io -f -c "pwrite 0 1k" -c "sync" -c "falloc 0 4k" \ + -c "pwrite 4k 4k" /mnt/btrfs/file + # umount /mnt/btrfs + # ./grub-fstest ./grub-fstest --debug=btrfs ~/test.img hex "/file" + + Such mixed inline/regular extents case is not recommended layout, + but all existing tools and kernel can handle it without problem + +2. NO_HOLES feature + # mkfs.btrfs -f test.img -O no_holes + # mount test.img /mnt/btrfs + # xfs_io -f -c "pwrite 0 4k" -c "pwrite 8k 4k" /mnt/btrfs/file + # umount /mnt/btrfs + # ./grub-fstest ./grub-fstest --debug=btrfs ~/test.img hex "/file" + + NO_HOLES feature is going to be the default mkfs feature in the incoming + v5.15 release, and kernel has support for it since v4.0. + +[CAUSE] +The way GRUB btrfs code iterates through file extents relies on no gap +between extents. + +If any gap is hit, then grub btrfs will error out, without any proper +reason to help debug the bug. + +This is a bad assumption, since a long long time ago btrfs has a new +feature called NO_HOLES to allow btrfs to skip the padding hole extent +to reduce metadata usage. + +The NO_HOLES feature is already stable since kernel v4.0 and is going to +be the default mkfs feature in the incoming v5.15 btrfs-progs release. + +[FIX] +When there is a extent gap, instead of error out, just try next item. + +This is still not ideal, as kernel/progs/U-boot all do the iteration +item by item, not relying on the file offset continuity. + +But it will be way more time consuming to correct the whole behavior +than starting from scratch to build a proper designed btrfs module for GRUB. + +Signed-off-by: Qu Wenruo +Reviewed-by: Daniel Kiper +--- + grub-core/fs/btrfs.c | 35 ++++++++++++++++++++++++++++++++--- + 1 file changed, 32 insertions(+), 3 deletions(-) + +diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c +index 9625bdf16..b8625197b 100644 +--- a/grub-core/fs/btrfs.c ++++ b/grub-core/fs/btrfs.c +@@ -1506,6 +1506,7 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data, + grub_size_t csize; + grub_err_t err; + grub_off_t extoff; ++ struct grub_btrfs_leaf_descriptor desc; + if (!data->extent || data->extstart > pos || data->extino != ino + || data->exttree != tree || data->extend <= pos) + { +@@ -1518,7 +1519,7 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data, + key_in.type = GRUB_BTRFS_ITEM_TYPE_EXTENT_ITEM; + key_in.offset = grub_cpu_to_le64 (pos); + err = lower_bound (data, &key_in, &key_out, tree, +- &elemaddr, &elemsize, NULL, 0); ++ &elemaddr, &elemsize, &desc, 0); + if (err) + return -1; + if (key_out.object_id != ino +@@ -1557,10 +1558,38 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data, + PRIxGRUB_UINT64_T "\n", + grub_le_to_cpu64 (key_out.offset), + grub_le_to_cpu64 (data->extent->size)); ++ /* ++ * The way of extent item iteration is pretty bad, it completely ++ * requires all extents are contiguous, which is not ensured. ++ * ++ * Features like NO_HOLE and mixed inline/regular extents can cause ++ * gaps between file extent items. ++ * ++ * The correct way is to follow kernel/U-boot to iterate item by ++ * item, without any assumption on the file offset continuity. ++ * ++ * Here we just manually skip to next item and re-do the verification. ++ * ++ * TODO: Rework the whole extent item iteration code, if not the ++ * whole btrfs implementation. ++ */ + if (data->extend <= pos) + { +- grub_error (GRUB_ERR_BAD_FS, "extent not found"); +- return -1; ++ err = next(data, &desc, &elemaddr, &elemsize, &key_out); ++ if (err < 0) ++ return -1; ++ /* No next item for the inode, we hit the end */ ++ if (err == 0 || key_out.object_id != ino || ++ key_out.type != GRUB_BTRFS_ITEM_TYPE_EXTENT_ITEM) ++ return pos - pos0; ++ ++ csize = grub_le_to_cpu64(key_out.offset) - pos; ++ if (csize > len) ++ csize = len; ++ buf += csize; ++ pos += csize; ++ len -= csize; ++ continue; + } + } + csize = data->extend - pos; +-- +2.31.1 + diff --git a/grub2.changes b/grub2.changes index 2110cd7..8aa09d6 100644 --- a/grub2.changes +++ b/grub2.changes @@ -1,3 +1,9 @@ +------------------------------------------------------------------- +Mon Dec 6 01:21:07 UTC 2021 - Michael Chang + +- Fix extent not found when initramfs contains shared extents (bsc#1190982) + * 0001-fs-btrfs-Make-extent-item-iteration-to-handle-gaps.patch + ------------------------------------------------------------------- Thu Nov 11 07:45:11 UTC 2021 - Michael Chang diff --git a/grub2.spec b/grub2.spec index 577788e..e73eeca 100644 --- a/grub2.spec +++ b/grub2.spec @@ -314,6 +314,7 @@ Patch796: 0001-disk-diskfilter-Use-nodes-in-logical-volume-s-segmen.patch Patch797: 0001-fs-xfs-Fix-unreadable-filesystem-with-v4-superblock.patch Patch798: 0001-arm64-Fix-EFI-loader-kernel-image-allocation.patch Patch799: 0002-Arm-check-for-the-PE-magic-for-the-compiled-arch.patch +Patch800: 0001-fs-btrfs-Make-extent-item-iteration-to-handle-gaps.patch Requires: gettext-runtime %if 0%{?suse_version} >= 1140