|
 |
5593c8 |
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
|
|
5593c8 |
From: Erwan Velu <erwanaliasr1@gmail.com>
|
|
|
5593c8 |
Date: Wed, 25 Aug 2021 15:31:52 +0200
|
|
|
5593c8 |
Subject: [PATCH] fs/xfs: Fix unreadable filesystem with v4 superblock
|
|
|
5593c8 |
|
|
|
5593c8 |
The commit 8b1e5d193 (fs/xfs: Add bigtime incompat feature support)
|
|
|
5593c8 |
introduced the bigtime support by adding some features in v3 inodes.
|
|
|
5593c8 |
This change extended grub_xfs_inode struct by 76 bytes but also changed
|
|
|
5593c8 |
the computation of XFS_V2_INODE_SIZE and XFS_V3_INODE_SIZE. Prior this
|
|
|
5593c8 |
commit, XFS_V2_INODE_SIZE was 100 bytes. After the commit it's 84 bytes
|
|
|
5593c8 |
XFS_V2_INODE_SIZE becomes 16 bytes too small.
|
|
|
5593c8 |
|
|
|
5593c8 |
As a result, the data structures aren't properly aligned and the GRUB
|
|
|
5593c8 |
generates "attempt to read or write outside of partition" errors when
|
|
|
5593c8 |
trying to read the XFS filesystem:
|
|
|
5593c8 |
|
|
|
5593c8 |
GNU GRUB version 2.11
|
|
|
5593c8 |
....
|
|
|
5593c8 |
grub> set debug=efi,gpt,xfs
|
|
|
5593c8 |
grub> insmod part_gpt
|
|
|
5593c8 |
grub> ls (hd0,gpt1)/
|
|
|
5593c8 |
partmap/gpt.c:93: Read a valid GPT header
|
|
|
5593c8 |
partmap/gpt.c:115: GPT entry 0: start=4096, length=1953125
|
|
|
5593c8 |
fs/xfs.c:931: Reading sb
|
|
|
5593c8 |
fs/xfs.c:270: Validating superblock
|
|
|
5593c8 |
fs/xfs.c:295: XFS v4 superblock detected
|
|
|
5593c8 |
fs/xfs.c:962: Reading root ino 128
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (128) - 64, 0
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (739521961424144223) - 344365866970255880, 3840
|
|
|
5593c8 |
error: attempt to read or write outside of partition.
|
|
|
5593c8 |
|
|
|
5593c8 |
This commit change the XFS_V2_INODE_SIZE computation by subtracting 76
|
|
|
5593c8 |
bytes instead of 92 bytes from the actual size of grub_xfs_inode struct.
|
|
|
5593c8 |
This 76 bytes value comes from added members:
|
|
|
5593c8 |
20 grub_uint8_t unused5
|
|
|
5593c8 |
1 grub_uint64_t flags2
|
|
|
5593c8 |
48 grub_uint8_t unused6
|
|
|
5593c8 |
|
|
|
5593c8 |
This patch explicitly splits the v2 and v3 parts of the structure.
|
|
|
5593c8 |
The unused4 is still ending of the v2 structures and the v3 starts
|
|
|
5593c8 |
at unused5. Thanks to this we will avoid future corruptions of v2
|
|
|
5593c8 |
or v3 inodes.
|
|
|
5593c8 |
|
|
|
5593c8 |
The XFS_V2_INODE_SIZE is returning to its expected size and the
|
|
|
5593c8 |
filesystem is back to a readable state:
|
|
|
5593c8 |
|
|
|
5593c8 |
GNU GRUB version 2.11
|
|
|
5593c8 |
....
|
|
|
5593c8 |
grub> set debug=efi,gpt,xfs
|
|
|
5593c8 |
grub> insmod part_gpt
|
|
|
5593c8 |
grub> ls (hd0,gpt1)/
|
|
|
5593c8 |
partmap/gpt.c:93: Read a valid GPT header
|
|
|
5593c8 |
partmap/gpt.c:115: GPT entry 0: start=4096, length=1953125
|
|
|
5593c8 |
fs/xfs.c:931: Reading sb
|
|
|
5593c8 |
fs/xfs.c:270: Validating superblock
|
|
|
5593c8 |
fs/xfs.c:295: XFS v4 superblock detected
|
|
|
5593c8 |
fs/xfs.c:962: Reading root ino 128
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (128) - 64, 0
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (128) - 64, 0
|
|
|
5593c8 |
fs/xfs.c:931: Reading sb
|
|
|
5593c8 |
fs/xfs.c:270: Validating superblock
|
|
|
5593c8 |
fs/xfs.c:295: XFS v4 superblock detected
|
|
|
5593c8 |
fs/xfs.c:962: Reading root ino 128
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (128) - 64, 0
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (128) - 64, 0
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (128) - 64, 0
|
|
|
5593c8 |
fs/xfs.c:515: Reading inode (131) - 64, 768
|
|
|
5593c8 |
efi/ fs/xfs.c:515: Reading inode (3145856) - 1464904, 0
|
|
|
5593c8 |
grub2/ fs/xfs.c:515: Reading inode (132) - 64, 1024
|
|
|
5593c8 |
grub/ fs/xfs.c:515: Reading inode (139) - 64, 2816
|
|
|
5593c8 |
grub>
|
|
|
5593c8 |
|
|
|
5593c8 |
Fixes: 8b1e5d193 (fs/xfs: Add bigtime incompat feature support)
|
|
|
5593c8 |
|
|
|
5593c8 |
Signed-off-by: Erwan Velu <e.velu@criteo.com>
|
|
|
5593c8 |
Tested-by: Carlos Maiolino <cmaiolino@redhat.com>
|
|
|
5593c8 |
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
|
|
|
5593c8 |
(cherry picked from commit a4b495520e4dc41a896a8b916a64eda9970c50ea)
|
|
|
5593c8 |
---
|
|
|
5593c8 |
grub-core/fs/xfs.c | 14 ++++++++++----
|
|
|
5593c8 |
1 file changed, 10 insertions(+), 4 deletions(-)
|
|
|
5593c8 |
|
|
|
5593c8 |
diff --git a/grub-core/fs/xfs.c b/grub-core/fs/xfs.c
|
|
|
5593c8 |
index 0f524c3a8a6..e3816d1ec4a 100644
|
|
|
5593c8 |
--- a/grub-core/fs/xfs.c
|
|
|
5593c8 |
+++ b/grub-core/fs/xfs.c
|
|
|
5593c8 |
@@ -192,6 +192,11 @@ struct grub_xfs_time_legacy
|
|
|
5593c8 |
grub_uint32_t nanosec;
|
|
|
5593c8 |
} GRUB_PACKED;
|
|
|
5593c8 |
|
|
|
5593c8 |
+/*
|
|
|
5593c8 |
+ * The struct grub_xfs_inode layout was taken from the
|
|
|
5593c8 |
+ * struct xfs_dinode_core which is described here:
|
|
|
5593c8 |
+ * https://mirrors.edge.kernel.org/pub/linux/utils/fs/xfs/docs/xfs_filesystem_structure.pdf
|
|
|
5593c8 |
+ */
|
|
|
5593c8 |
struct grub_xfs_inode
|
|
|
5593c8 |
{
|
|
|
5593c8 |
grub_uint8_t magic[2];
|
|
|
5593c8 |
@@ -208,14 +213,15 @@ struct grub_xfs_inode
|
|
|
5593c8 |
grub_uint32_t nextents;
|
|
|
5593c8 |
grub_uint16_t unused3;
|
|
|
5593c8 |
grub_uint8_t fork_offset;
|
|
|
5593c8 |
- grub_uint8_t unused4[37];
|
|
|
5593c8 |
+ grub_uint8_t unused4[17]; /* Last member of inode v2. */
|
|
|
5593c8 |
+ grub_uint8_t unused5[20]; /* First member of inode v3. */
|
|
|
5593c8 |
grub_uint64_t flags2;
|
|
|
5593c8 |
- grub_uint8_t unused5[48];
|
|
|
5593c8 |
+ grub_uint8_t unused6[48]; /* Last member of inode v3. */
|
|
|
5593c8 |
} GRUB_PACKED;
|
|
|
5593c8 |
|
|
|
5593c8 |
#define XFS_V3_INODE_SIZE sizeof(struct grub_xfs_inode)
|
|
|
5593c8 |
-/* Size of struct grub_xfs_inode until fork_offset (included). */
|
|
|
5593c8 |
-#define XFS_V2_INODE_SIZE (XFS_V3_INODE_SIZE - 92)
|
|
|
5593c8 |
+/* Size of struct grub_xfs_inode v2, up to unused4 member included. */
|
|
|
5593c8 |
+#define XFS_V2_INODE_SIZE (XFS_V3_INODE_SIZE - 76)
|
|
|
5593c8 |
|
|
|
5593c8 |
struct grub_xfs_dirblock_tail
|
|
|
5593c8 |
{
|