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From: Christoph Hellwig <hch@lst.de>
To: linux-xfs@vger.kernel.org
Subject: [PATCH, RFC] libxfs: check the size of on-disk data structures
Date: Wed,  8 Nov 2023 17:33:16 +0100	[thread overview]
Message-ID: <20231108163316.493089-1-hch@lst.de> (raw)

Provide a dumb BUILD_BUG_ON_MSG and import the kernel xfs_ondisk.h file
so that libxfs_init can check the size of all relevant on-disk
structures.

This seems like a better way to verify the struct size in userspace
compared to the xfs/122 test in xfstests that needs constant updates.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---

Note that xfs_ondisk.h should move to libxfs if this gets applied.

 include/xfs.h       |   4 +
 libxfs/init.c       |   7 ++
 libxfs/xfs_ondisk.h | 195 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 206 insertions(+)
 create mode 100644 libxfs/xfs_ondisk.h

diff --git a/include/xfs.h b/include/xfs.h
index e97158c8d..796af1f37 100644
--- a/include/xfs.h
+++ b/include/xfs.h
@@ -38,6 +38,10 @@ extern int xfs_assert_largefile[sizeof(off_t)-8];
 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 #endif
 
+#ifndef BUILD_BUG_ON_MSG
+#define BUILD_BUG_ON_MSG(a, b)	BUILD_BUG_ON(a)
+#endif
+
 #define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
 
 #include <xfs/xfs_types.h>
diff --git a/libxfs/init.c b/libxfs/init.c
index ce6e62cde..aa37ef651 100644
--- a/libxfs/init.c
+++ b/libxfs/init.c
@@ -23,6 +23,11 @@
 #include "xfs_refcount_btree.h"
 #include "libfrog/platform.h"
 
+#include "xfs_format.h"
+#include "xfs_da_format.h"
+#include "xfs_log_format.h"
+#include "xfs_ondisk.h"
+
 #include "libxfs.h"		/* for now */
 
 #ifndef HAVE_LIBURCU_ATOMIC64
@@ -317,6 +322,8 @@ libxfs_init(libxfs_init_t *a)
 	int		rval = 0;
 	int		flags;
 
+	xfs_check_ondisk_structs();
+
 	dpath[0] = logpath[0] = rtpath[0] = '\0';
 	dname = a->dname;
 	logname = a->logname;
diff --git a/libxfs/xfs_ondisk.h b/libxfs/xfs_ondisk.h
new file mode 100644
index 000000000..c4cc99b70
--- /dev/null
+++ b/libxfs/xfs_ondisk.h
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016 Oracle.
+ * All Rights Reserved.
+ */
+#ifndef __XFS_ONDISK_H
+#define __XFS_ONDISK_H
+
+#define XFS_CHECK_STRUCT_SIZE(structname, size) \
+	BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(" \
+		#structname ") is wrong, expected " #size)
+
+#define XFS_CHECK_OFFSET(structname, member, off) \
+	BUILD_BUG_ON_MSG(offsetof(structname, member) != (off), \
+		"XFS: offsetof(" #structname ", " #member ") is wrong, " \
+		"expected " #off)
+
+#define XFS_CHECK_VALUE(value, expected) \
+	BUILD_BUG_ON_MSG((value) != (expected), \
+		"XFS: value of " #value " is wrong, expected " #expected)
+
+static inline void __init
+xfs_check_ondisk_structs(void)
+{
+	/* ag/file structures */
+	XFS_CHECK_STRUCT_SIZE(struct xfs_acl,			4);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_acl_entry,		12);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_agf,			224);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_agfl,			36);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			344);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_key,		8);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_rec,		16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_bmdr_block,		4);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_btree_block_shdr,	48);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_btree_block_lhdr,	64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_btree_block,		72);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dinode,		176);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_disk_dquot,		104);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dqblk,			136);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dsb,			264);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dsymlink_hdr,		56);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_inobt_key,		4);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_inobt_rec,		16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_refcount_key,		4);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_refcount_rec,		12);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_rmap_key,		20);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_rmap_rec,		24);
+	XFS_CHECK_STRUCT_SIZE(xfs_timestamp_t,			8);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_legacy_timestamp,	8);
+	XFS_CHECK_STRUCT_SIZE(xfs_alloc_key_t,			8);
+	XFS_CHECK_STRUCT_SIZE(xfs_alloc_ptr_t,			4);
+	XFS_CHECK_STRUCT_SIZE(xfs_alloc_rec_t,			8);
+	XFS_CHECK_STRUCT_SIZE(xfs_inobt_ptr_t,			4);
+	XFS_CHECK_STRUCT_SIZE(xfs_refcount_ptr_t,		4);
+	XFS_CHECK_STRUCT_SIZE(xfs_rmap_ptr_t,			4);
+
+	/* dir/attr trees */
+	XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_leaf_hdr,	80);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_leafblock,	80);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_rmt_hdr,		56);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_da3_blkinfo,		56);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_da3_intnode,		64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_da3_node_hdr,		64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dir3_blk_hdr,		48);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dir3_data_hdr,		64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dir3_free,		64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dir3_free_hdr,		64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dir3_leaf,		64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dir3_leaf_hdr,		64);
+	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_entry_t,		8);
+	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_hdr_t,		32);
+	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_map_t,		4);
+	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_local_t,	4);
+
+	/*
+	 * m68k has problems with xfs_attr_leaf_name_remote_t, but we pad it to
+	 * 4 bytes anyway so it's not obviously a problem.  Hence for the moment
+	 * we don't check this structure. This can be re-instated when the attr
+	 * definitions are updated to use c99 VLA definitions.
+	 *
+	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_remote_t,	12);
+	 */
+
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, valuelen,	0);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, namelen,	2);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, nameval,	3);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valueblk,	0);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen,	4);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen,	8);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name,	9);
+	XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t,		32);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_attr_shortform,	4);
+	XFS_CHECK_OFFSET(struct xfs_attr_shortform, hdr.totsize, 0);
+	XFS_CHECK_OFFSET(struct xfs_attr_shortform, hdr.count,	 2);
+	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].namelen,	4);
+	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].valuelen,	5);
+	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].flags,	6);
+	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].nameval,	7);
+	XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t,			12);
+	XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t,			16);
+	XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t,		8);
+	XFS_CHECK_STRUCT_SIZE(xfs_da_node_hdr_t,		16);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_free_t,		4);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_hdr_t,		16);
+	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, freetag,	0);
+	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, length,	2);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_hdr_t,		16);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_t,			16);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_entry_t,		8);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_hdr_t,		16);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_t,			16);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_tail_t,		4);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_entry_t,		3);
+	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, namelen,		0);
+	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, offset,		1);
+	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, name,		3);
+	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_hdr_t,		10);
+
+	/* log structures */
+	XFS_CHECK_STRUCT_SIZE(struct xfs_buf_log_format,	88);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat,		24);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_extent_32,		12);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_extent_64,		16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_log_dinode,		176);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_icreate_log,		28);
+	XFS_CHECK_STRUCT_SIZE(xfs_log_timestamp_t,		8);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_log_legacy_timestamp,	8);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_inode_log_format_32,	52);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_inode_log_format,	56);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_qoff_logformat,	20);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_trans_header,		16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_attri_log_format,	40);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_attrd_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_bui_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_bud_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_cui_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_cud_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_rui_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_rud_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_map_extent,		32);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_phys_extent,		16);
+
+	XFS_CHECK_OFFSET(struct xfs_bui_log_format, bui_extents,	16);
+	XFS_CHECK_OFFSET(struct xfs_cui_log_format, cui_extents,	16);
+	XFS_CHECK_OFFSET(struct xfs_rui_log_format, rui_extents,	16);
+	XFS_CHECK_OFFSET(struct xfs_efi_log_format, efi_extents,	16);
+	XFS_CHECK_OFFSET(struct xfs_efi_log_format_32, efi_extents,	16);
+	XFS_CHECK_OFFSET(struct xfs_efi_log_format_64, efi_extents,	16);
+
+	/*
+	 * The v5 superblock format extended several v4 header structures with
+	 * additional data. While new fields are only accessible on v5
+	 * superblocks, it's important that the v5 structures place original v4
+	 * fields/headers in the correct location on-disk. For example, we must
+	 * be able to find magic values at the same location in certain blocks
+	 * regardless of superblock version.
+	 *
+	 * The following checks ensure that various v5 data structures place the
+	 * subset of v4 metadata associated with the same type of block at the
+	 * start of the on-disk block. If there is no data structure definition
+	 * for certain types of v4 blocks, traverse down to the first field of
+	 * common metadata (e.g., magic value) and make sure it is at offset
+	 * zero.
+	 */
+	XFS_CHECK_OFFSET(struct xfs_dir3_leaf, hdr.info.hdr,	0);
+	XFS_CHECK_OFFSET(struct xfs_da3_intnode, hdr.info.hdr,	0);
+	XFS_CHECK_OFFSET(struct xfs_dir3_data_hdr, hdr.magic,	0);
+	XFS_CHECK_OFFSET(struct xfs_dir3_free, hdr.hdr.magic,	0);
+	XFS_CHECK_OFFSET(struct xfs_attr3_leafblock, hdr.info.hdr, 0);
+
+	XFS_CHECK_STRUCT_SIZE(struct xfs_bulkstat,		192);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_inumbers,		24);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_bulkstat_req,		64);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_inumbers_req,		64);
+
+	/*
+	 * Make sure the incore inode timestamp range corresponds to hand
+	 * converted values based on the ondisk format specification.
+	 */
+	XFS_CHECK_VALUE(XFS_BIGTIME_TIME_MIN - XFS_BIGTIME_EPOCH_OFFSET,
+			XFS_LEGACY_TIME_MIN);
+	XFS_CHECK_VALUE(XFS_BIGTIME_TIME_MAX - XFS_BIGTIME_EPOCH_OFFSET,
+			16299260424LL);
+
+	/* Do the same with the incore quota expiration range. */
+	XFS_CHECK_VALUE(XFS_DQ_BIGTIME_EXPIRY_MIN << XFS_DQ_BIGTIME_SHIFT, 4);
+	XFS_CHECK_VALUE(XFS_DQ_BIGTIME_EXPIRY_MAX << XFS_DQ_BIGTIME_SHIFT,
+			16299260424LL);
+}
+
+#endif /* __XFS_ONDISK_H */
-- 
2.39.2


             reply	other threads:[~2023-11-08 16:33 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-08 16:33 Christoph Hellwig [this message]
2023-11-09 19:52 ` [PATCH, RFC] libxfs: check the size of on-disk data structures Darrick J. Wong
2023-11-10  5:08   ` Christoph Hellwig
2023-12-01  2:06     ` Darrick J. Wong
2023-12-04  4:37       ` Christoph Hellwig
2023-12-04 19:53         ` Darrick J. Wong
2023-12-04 20:04           ` Christoph Hellwig

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