xref: /openbmc/linux/fs/xfs/scrub/attr.h (revision 2326f3cd)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * Copyright (C) 2019 Oracle.  All Rights Reserved.
4  * Author: Darrick J. Wong <darrick.wong@oracle.com>
5  */
6 #ifndef __XFS_SCRUB_ATTR_H__
7 #define __XFS_SCRUB_ATTR_H__
8 
9 /*
10  * Temporary storage for online scrub and repair of extended attributes.
11  */
12 struct xchk_xattr_buf {
13 	/* Size of @buf, in bytes. */
14 	size_t			sz;
15 
16 	/*
17 	 * Memory buffer -- either used for extracting attr values while
18 	 * walking the attributes; or for computing attr block bitmaps when
19 	 * checking the attribute tree.
20 	 *
21 	 * Each bitmap contains enough bits to track every byte in an attr
22 	 * block (rounded up to the size of an unsigned long).  The attr block
23 	 * used space bitmap starts at the beginning of the buffer; the free
24 	 * space bitmap follows immediately after; and we have a third buffer
25 	 * for storing intermediate bitmap results.
26 	 */
27 	uint8_t			buf[0];
28 };
29 
30 /* A place to store attribute values. */
31 static inline uint8_t *
32 xchk_xattr_valuebuf(
33 	struct xfs_scrub	*sc)
34 {
35 	struct xchk_xattr_buf	*ab = sc->buf;
36 
37 	return ab->buf;
38 }
39 
40 /* A bitmap of space usage computed by walking an attr leaf block. */
41 static inline unsigned long *
42 xchk_xattr_usedmap(
43 	struct xfs_scrub	*sc)
44 {
45 	struct xchk_xattr_buf	*ab = sc->buf;
46 
47 	return (unsigned long *)ab->buf;
48 }
49 
50 /* A bitmap of free space computed by walking attr leaf block free info. */
51 static inline unsigned long *
52 xchk_xattr_freemap(
53 	struct xfs_scrub	*sc)
54 {
55 	return xchk_xattr_usedmap(sc) +
56 			BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
57 }
58 
59 /* A bitmap used to hold temporary results. */
60 static inline unsigned long *
61 xchk_xattr_dstmap(
62 	struct xfs_scrub	*sc)
63 {
64 	return xchk_xattr_freemap(sc) +
65 			BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
66 }
67 
68 #endif	/* __XFS_SCRUB_ATTR_H__ */
69