cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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health.c (7417B)


      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * Copyright (C) 2019 Oracle.  All Rights Reserved.
      4 * Author: Darrick J. Wong <darrick.wong@oracle.com>
      5 */
      6#include "xfs.h"
      7#include "xfs_fs.h"
      8#include "xfs_shared.h"
      9#include "xfs_format.h"
     10#include "xfs_btree.h"
     11#include "xfs_ag.h"
     12#include "xfs_health.h"
     13#include "scrub/scrub.h"
     14#include "scrub/health.h"
     15
     16/*
     17 * Scrub and In-Core Filesystem Health Assessments
     18 * ===============================================
     19 *
     20 * Online scrub and repair have the time and the ability to perform stronger
     21 * checks than we can do from the metadata verifiers, because they can
     22 * cross-reference records between data structures.  Therefore, scrub is in a
     23 * good position to update the online filesystem health assessments to reflect
     24 * the good/bad state of the data structure.
     25 *
     26 * We therefore extend scrub in the following ways to achieve this:
     27 *
     28 * 1. Create a "sick_mask" field in the scrub context.  When we're setting up a
     29 * scrub call, set this to the default XFS_SICK_* flag(s) for the selected
     30 * scrub type (call it A).  Scrub and repair functions can override the default
     31 * sick_mask value if they choose.
     32 *
     33 * 2. If the scrubber returns a runtime error code, we exit making no changes
     34 * to the incore sick state.
     35 *
     36 * 3. If the scrubber finds that A is clean, use sick_mask to clear the incore
     37 * sick flags before exiting.
     38 *
     39 * 4. If the scrubber finds that A is corrupt, use sick_mask to set the incore
     40 * sick flags.  If the user didn't want to repair then we exit, leaving the
     41 * metadata structure unfixed and the sick flag set.
     42 *
     43 * 5. Now we know that A is corrupt and the user wants to repair, so run the
     44 * repairer.  If the repairer returns an error code, we exit with that error
     45 * code, having made no further changes to the incore sick state.
     46 *
     47 * 6. If repair rebuilds A correctly and the subsequent re-scrub of A is clean,
     48 * use sick_mask to clear the incore sick flags.  This should have the effect
     49 * that A is no longer marked sick.
     50 *
     51 * 7. If repair rebuilds A incorrectly, the re-scrub will find it corrupt and
     52 * use sick_mask to set the incore sick flags.  This should have no externally
     53 * visible effect since we already set them in step (4).
     54 *
     55 * There are some complications to this story, however.  For certain types of
     56 * complementary metadata indices (e.g. inobt/finobt), it is easier to rebuild
     57 * both structures at the same time.  The following principles apply to this
     58 * type of repair strategy:
     59 *
     60 * 8. Any repair function that rebuilds multiple structures should update
     61 * sick_mask_visible to reflect whatever other structures are rebuilt, and
     62 * verify that all the rebuilt structures can pass a scrub check.  The outcomes
     63 * of 5-7 still apply, but with a sick_mask that covers everything being
     64 * rebuilt.
     65 */
     66
     67/* Map our scrub type to a sick mask and a set of health update functions. */
     68
     69enum xchk_health_group {
     70	XHG_FS = 1,
     71	XHG_RT,
     72	XHG_AG,
     73	XHG_INO,
     74};
     75
     76struct xchk_health_map {
     77	enum xchk_health_group	group;
     78	unsigned int		sick_mask;
     79};
     80
     81static const struct xchk_health_map type_to_health_flag[XFS_SCRUB_TYPE_NR] = {
     82	[XFS_SCRUB_TYPE_SB]		= { XHG_AG,  XFS_SICK_AG_SB },
     83	[XFS_SCRUB_TYPE_AGF]		= { XHG_AG,  XFS_SICK_AG_AGF },
     84	[XFS_SCRUB_TYPE_AGFL]		= { XHG_AG,  XFS_SICK_AG_AGFL },
     85	[XFS_SCRUB_TYPE_AGI]		= { XHG_AG,  XFS_SICK_AG_AGI },
     86	[XFS_SCRUB_TYPE_BNOBT]		= { XHG_AG,  XFS_SICK_AG_BNOBT },
     87	[XFS_SCRUB_TYPE_CNTBT]		= { XHG_AG,  XFS_SICK_AG_CNTBT },
     88	[XFS_SCRUB_TYPE_INOBT]		= { XHG_AG,  XFS_SICK_AG_INOBT },
     89	[XFS_SCRUB_TYPE_FINOBT]		= { XHG_AG,  XFS_SICK_AG_FINOBT },
     90	[XFS_SCRUB_TYPE_RMAPBT]		= { XHG_AG,  XFS_SICK_AG_RMAPBT },
     91	[XFS_SCRUB_TYPE_REFCNTBT]	= { XHG_AG,  XFS_SICK_AG_REFCNTBT },
     92	[XFS_SCRUB_TYPE_INODE]		= { XHG_INO, XFS_SICK_INO_CORE },
     93	[XFS_SCRUB_TYPE_BMBTD]		= { XHG_INO, XFS_SICK_INO_BMBTD },
     94	[XFS_SCRUB_TYPE_BMBTA]		= { XHG_INO, XFS_SICK_INO_BMBTA },
     95	[XFS_SCRUB_TYPE_BMBTC]		= { XHG_INO, XFS_SICK_INO_BMBTC },
     96	[XFS_SCRUB_TYPE_DIR]		= { XHG_INO, XFS_SICK_INO_DIR },
     97	[XFS_SCRUB_TYPE_XATTR]		= { XHG_INO, XFS_SICK_INO_XATTR },
     98	[XFS_SCRUB_TYPE_SYMLINK]	= { XHG_INO, XFS_SICK_INO_SYMLINK },
     99	[XFS_SCRUB_TYPE_PARENT]		= { XHG_INO, XFS_SICK_INO_PARENT },
    100	[XFS_SCRUB_TYPE_RTBITMAP]	= { XHG_RT,  XFS_SICK_RT_BITMAP },
    101	[XFS_SCRUB_TYPE_RTSUM]		= { XHG_RT,  XFS_SICK_RT_SUMMARY },
    102	[XFS_SCRUB_TYPE_UQUOTA]		= { XHG_FS,  XFS_SICK_FS_UQUOTA },
    103	[XFS_SCRUB_TYPE_GQUOTA]		= { XHG_FS,  XFS_SICK_FS_GQUOTA },
    104	[XFS_SCRUB_TYPE_PQUOTA]		= { XHG_FS,  XFS_SICK_FS_PQUOTA },
    105	[XFS_SCRUB_TYPE_FSCOUNTERS]	= { XHG_FS,  XFS_SICK_FS_COUNTERS },
    106};
    107
    108/* Return the health status mask for this scrub type. */
    109unsigned int
    110xchk_health_mask_for_scrub_type(
    111	__u32			scrub_type)
    112{
    113	return type_to_health_flag[scrub_type].sick_mask;
    114}
    115
    116/*
    117 * Update filesystem health assessments based on what we found and did.
    118 *
    119 * If the scrubber finds errors, we mark sick whatever's mentioned in
    120 * sick_mask, no matter whether this is a first scan or an
    121 * evaluation of repair effectiveness.
    122 *
    123 * Otherwise, no direct corruption was found, so mark whatever's in
    124 * sick_mask as healthy.
    125 */
    126void
    127xchk_update_health(
    128	struct xfs_scrub	*sc)
    129{
    130	struct xfs_perag	*pag;
    131	bool			bad;
    132
    133	if (!sc->sick_mask)
    134		return;
    135
    136	bad = (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
    137				   XFS_SCRUB_OFLAG_XCORRUPT));
    138	switch (type_to_health_flag[sc->sm->sm_type].group) {
    139	case XHG_AG:
    140		pag = xfs_perag_get(sc->mp, sc->sm->sm_agno);
    141		if (bad)
    142			xfs_ag_mark_sick(pag, sc->sick_mask);
    143		else
    144			xfs_ag_mark_healthy(pag, sc->sick_mask);
    145		xfs_perag_put(pag);
    146		break;
    147	case XHG_INO:
    148		if (!sc->ip)
    149			return;
    150		if (bad)
    151			xfs_inode_mark_sick(sc->ip, sc->sick_mask);
    152		else
    153			xfs_inode_mark_healthy(sc->ip, sc->sick_mask);
    154		break;
    155	case XHG_FS:
    156		if (bad)
    157			xfs_fs_mark_sick(sc->mp, sc->sick_mask);
    158		else
    159			xfs_fs_mark_healthy(sc->mp, sc->sick_mask);
    160		break;
    161	case XHG_RT:
    162		if (bad)
    163			xfs_rt_mark_sick(sc->mp, sc->sick_mask);
    164		else
    165			xfs_rt_mark_healthy(sc->mp, sc->sick_mask);
    166		break;
    167	default:
    168		ASSERT(0);
    169		break;
    170	}
    171}
    172
    173/* Is the given per-AG btree healthy enough for scanning? */
    174bool
    175xchk_ag_btree_healthy_enough(
    176	struct xfs_scrub	*sc,
    177	struct xfs_perag	*pag,
    178	xfs_btnum_t		btnum)
    179{
    180	unsigned int		mask = 0;
    181
    182	/*
    183	 * We always want the cursor if it's the same type as whatever we're
    184	 * scrubbing, even if we already know the structure is corrupt.
    185	 *
    186	 * Otherwise, we're only interested in the btree for cross-referencing.
    187	 * If we know the btree is bad then don't bother, just set XFAIL.
    188	 */
    189	switch (btnum) {
    190	case XFS_BTNUM_BNO:
    191		if (sc->sm->sm_type == XFS_SCRUB_TYPE_BNOBT)
    192			return true;
    193		mask = XFS_SICK_AG_BNOBT;
    194		break;
    195	case XFS_BTNUM_CNT:
    196		if (sc->sm->sm_type == XFS_SCRUB_TYPE_CNTBT)
    197			return true;
    198		mask = XFS_SICK_AG_CNTBT;
    199		break;
    200	case XFS_BTNUM_INO:
    201		if (sc->sm->sm_type == XFS_SCRUB_TYPE_INOBT)
    202			return true;
    203		mask = XFS_SICK_AG_INOBT;
    204		break;
    205	case XFS_BTNUM_FINO:
    206		if (sc->sm->sm_type == XFS_SCRUB_TYPE_FINOBT)
    207			return true;
    208		mask = XFS_SICK_AG_FINOBT;
    209		break;
    210	case XFS_BTNUM_RMAP:
    211		if (sc->sm->sm_type == XFS_SCRUB_TYPE_RMAPBT)
    212			return true;
    213		mask = XFS_SICK_AG_RMAPBT;
    214		break;
    215	case XFS_BTNUM_REFC:
    216		if (sc->sm->sm_type == XFS_SCRUB_TYPE_REFCNTBT)
    217			return true;
    218		mask = XFS_SICK_AG_REFCNTBT;
    219		break;
    220	default:
    221		ASSERT(0);
    222		return true;
    223	}
    224
    225	if (xfs_ag_has_sickness(pag, mask)) {
    226		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XFAIL;
    227		return false;
    228	}
    229
    230	return true;
    231}