1 From cda0a857dd7a27cd5d621747464bfe71e8727fff Mon Sep 17 00:00:00 2001
2 From: Daniel Kiper <daniel.kiper@oracle.com>
3 Date: Tue, 29 May 2018 16:16:02 +0200
4 Subject: xfs: Accept filesystem with sparse inodes
5
6 The sparse inode metadata format became a mkfs.xfs default in
7 xfsprogs-4.16.0, and such filesystems are now rejected by grub as
8 containing an incompatible feature.
9
10 In essence, this feature allows xfs to allocate inodes into fragmented
11 freespace. (Without this feature, if xfs could not allocate contiguous
12 space for 64 new inodes, inode creation would fail.)
13
14 In practice, the disk format change is restricted to the inode btree,
15 which as far as I can tell is not used by grub. If all you're doing
16 today is parsing a directory, reading an inode number, and converting
17 that inode number to a disk location, then ignoring this feature
18 should be fine, so I've added it to XFS_SB_FEAT_INCOMPAT_SUPPORTED
19
20 I did some brief testing of this patch by hacking up the regression
21 tests to completely fragment freespace on the test xfs filesystem, and
22 then write a large-ish number of inodes to consume any existing
23 contiguous 64-inode chunk. This way any files the grub tests add and
24 traverse would be in such a fragmented inode allocation. Tests passed,
25 but I'm not sure how to cleanly integrate that into the test harness.
26
27 Signed-off-by: Eric Sandeen <sandeen@redhat.com>
28 Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
29 Tested-by: Chris Murphy <lists@colorremedies.com>
30 ---
31 grub-core/fs/xfs.c | 11 ++++++++++-
32 1 file changed, 10 insertions(+), 1 deletion(-)
33
34 diff --git a/grub-core/fs/xfs.c b/grub-core/fs/xfs.c
35 index c6031bd..3b00c74 100644
36 --- a/grub-core/fs/xfs.c
37 +++ b/grub-core/fs/xfs.c
38 @@ -79,9 +79,18 @@ GRUB_MOD_LICENSE ("GPLv3+");
39 #define XFS_SB_FEAT_INCOMPAT_SPINODES (1 << 1) /* sparse inode chunks */
40 #define XFS_SB_FEAT_INCOMPAT_META_UUID (1 << 2) /* metadata UUID */
41
42 -/* We do not currently verify metadata UUID so it is safe to read such filesystem */
43 +/*
44 + * Directory entries with ftype are explicitly handled by GRUB code.
45 + *
46 + * We do not currently read the inode btrees, so it is safe to read filesystems
47 + * with the XFS_SB_FEAT_INCOMPAT_SPINODES feature.
48 + *
49 + * We do not currently verify metadata UUID, so it is safe to read filesystems
50 + * with the XFS_SB_FEAT_INCOMPAT_META_UUID feature.
51 + */
52 #define XFS_SB_FEAT_INCOMPAT_SUPPORTED \
53 (XFS_SB_FEAT_INCOMPAT_FTYPE | \
54 + XFS_SB_FEAT_INCOMPAT_SPINODES | \
55 XFS_SB_FEAT_INCOMPAT_META_UUID)
56
57 struct grub_xfs_sblock
58 --
59 cgit v1.0-41-gc330
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