You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
118 lines
4.4 KiB
118 lines
4.4 KiB
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
|
From: Erwan Velu <erwanaliasr1@gmail.com> |
|
Date: Wed, 25 Aug 2021 15:31:52 +0200 |
|
Subject: [PATCH] fs/xfs: Fix unreadable filesystem with v4 superblock |
|
|
|
The commit 8b1e5d193 (fs/xfs: Add bigtime incompat feature support) |
|
introduced the bigtime support by adding some features in v3 inodes. |
|
This change extended grub_xfs_inode struct by 76 bytes but also changed |
|
the computation of XFS_V2_INODE_SIZE and XFS_V3_INODE_SIZE. Prior this |
|
commit, XFS_V2_INODE_SIZE was 100 bytes. After the commit it's 84 bytes |
|
XFS_V2_INODE_SIZE becomes 16 bytes too small. |
|
|
|
As a result, the data structures aren't properly aligned and the GRUB |
|
generates "attempt to read or write outside of partition" errors when |
|
trying to read the XFS filesystem: |
|
|
|
GNU GRUB version 2.11 |
|
.... |
|
grub> set debug=efi,gpt,xfs |
|
grub> insmod part_gpt |
|
grub> ls (hd0,gpt1)/ |
|
partmap/gpt.c:93: Read a valid GPT header |
|
partmap/gpt.c:115: GPT entry 0: start=4096, length=1953125 |
|
fs/xfs.c:931: Reading sb |
|
fs/xfs.c:270: Validating superblock |
|
fs/xfs.c:295: XFS v4 superblock detected |
|
fs/xfs.c:962: Reading root ino 128 |
|
fs/xfs.c:515: Reading inode (128) - 64, 0 |
|
fs/xfs.c:515: Reading inode (739521961424144223) - 344365866970255880, 3840 |
|
error: attempt to read or write outside of partition. |
|
|
|
This commit change the XFS_V2_INODE_SIZE computation by subtracting 76 |
|
bytes instead of 92 bytes from the actual size of grub_xfs_inode struct. |
|
This 76 bytes value comes from added members: |
|
20 grub_uint8_t unused5 |
|
1 grub_uint64_t flags2 |
|
48 grub_uint8_t unused6 |
|
|
|
This patch explicitly splits the v2 and v3 parts of the structure. |
|
The unused4 is still ending of the v2 structures and the v3 starts |
|
at unused5. Thanks to this we will avoid future corruptions of v2 |
|
or v3 inodes. |
|
|
|
The XFS_V2_INODE_SIZE is returning to its expected size and the |
|
filesystem is back to a readable state: |
|
|
|
GNU GRUB version 2.11 |
|
.... |
|
grub> set debug=efi,gpt,xfs |
|
grub> insmod part_gpt |
|
grub> ls (hd0,gpt1)/ |
|
partmap/gpt.c:93: Read a valid GPT header |
|
partmap/gpt.c:115: GPT entry 0: start=4096, length=1953125 |
|
fs/xfs.c:931: Reading sb |
|
fs/xfs.c:270: Validating superblock |
|
fs/xfs.c:295: XFS v4 superblock detected |
|
fs/xfs.c:962: Reading root ino 128 |
|
fs/xfs.c:515: Reading inode (128) - 64, 0 |
|
fs/xfs.c:515: Reading inode (128) - 64, 0 |
|
fs/xfs.c:931: Reading sb |
|
fs/xfs.c:270: Validating superblock |
|
fs/xfs.c:295: XFS v4 superblock detected |
|
fs/xfs.c:962: Reading root ino 128 |
|
fs/xfs.c:515: Reading inode (128) - 64, 0 |
|
fs/xfs.c:515: Reading inode (128) - 64, 0 |
|
fs/xfs.c:515: Reading inode (128) - 64, 0 |
|
fs/xfs.c:515: Reading inode (131) - 64, 768 |
|
efi/ fs/xfs.c:515: Reading inode (3145856) - 1464904, 0 |
|
grub2/ fs/xfs.c:515: Reading inode (132) - 64, 1024 |
|
grub/ fs/xfs.c:515: Reading inode (139) - 64, 2816 |
|
grub> |
|
|
|
Fixes: 8b1e5d193 (fs/xfs: Add bigtime incompat feature support) |
|
|
|
Signed-off-by: Erwan Velu <e.velu@criteo.com> |
|
Tested-by: Carlos Maiolino <cmaiolino@redhat.com> |
|
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> |
|
(cherry picked from commit a4b495520e4dc41a896a8b916a64eda9970c50ea) |
|
--- |
|
grub-core/fs/xfs.c | 14 ++++++++++---- |
|
1 file changed, 10 insertions(+), 4 deletions(-) |
|
|
|
diff --git a/grub-core/fs/xfs.c b/grub-core/fs/xfs.c |
|
index 0f524c3a8a6..e3816d1ec4a 100644 |
|
--- a/grub-core/fs/xfs.c |
|
+++ b/grub-core/fs/xfs.c |
|
@@ -192,6 +192,11 @@ struct grub_xfs_time_legacy |
|
grub_uint32_t nanosec; |
|
} GRUB_PACKED; |
|
|
|
+/* |
|
+ * The struct grub_xfs_inode layout was taken from the |
|
+ * struct xfs_dinode_core which is described here: |
|
+ * https://mirrors.edge.kernel.org/pub/linux/utils/fs/xfs/docs/xfs_filesystem_structure.pdf |
|
+ */ |
|
struct grub_xfs_inode |
|
{ |
|
grub_uint8_t magic[2]; |
|
@@ -208,14 +213,15 @@ struct grub_xfs_inode |
|
grub_uint32_t nextents; |
|
grub_uint16_t unused3; |
|
grub_uint8_t fork_offset; |
|
- grub_uint8_t unused4[37]; |
|
+ grub_uint8_t unused4[17]; /* Last member of inode v2. */ |
|
+ grub_uint8_t unused5[20]; /* First member of inode v3. */ |
|
grub_uint64_t flags2; |
|
- grub_uint8_t unused5[48]; |
|
+ grub_uint8_t unused6[48]; /* Last member of inode v3. */ |
|
} GRUB_PACKED; |
|
|
|
#define XFS_V3_INODE_SIZE sizeof(struct grub_xfs_inode) |
|
-/* Size of struct grub_xfs_inode until fork_offset (included). */ |
|
-#define XFS_V2_INODE_SIZE (XFS_V3_INODE_SIZE - 92) |
|
+/* Size of struct grub_xfs_inode v2, up to unused4 member included. */ |
|
+#define XFS_V2_INODE_SIZE (XFS_V3_INODE_SIZE - 76) |
|
|
|
struct grub_xfs_dirblock_tail |
|
{
|
|
|