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linux-stable/fs/xfs/scrub/common.c
Darrick J. Wong c3eabd3650 xfs: initial agnumber -> perag conversions for shrink 
If we want to use active references to the perag to be able to gate
 shrink removing AGs and hence perags safely, we've got a fair bit of
 work to do actually use perags in all the places we need to.
 
 There's a lot of code that iterates ag numbers and then
 looks up perags from that, often multiple times for the same perag
 in the one operation. If we want to use reference counted perags for
 access control, then we need to convert all these uses to perag
 iterators, not agno iterators.
 
 [Patches 1-4]
 
 The first step of this is consolidating all the perag management -
 init, free, get, put, etc into a common location. THis is spread all
 over the place right now, so move it all into libxfs/xfs_ag.[ch].
 This does expose kernel only bits of the perag to libxfs and hence
 userspace, so the structures and code is rearranged to minimise the
 number of ifdefs that need to be added to the userspace codebase.
 The perag iterator in xfs_icache.c is promoted to a first class API
 and expanded to the needs of the code as required.
 
 [Patches 5-10]
 
 These are the first basic perag iterator conversions and changes to
 pass the perag down the stack from those iterators where
 appropriate. A lot of this is obvious, simple changes, though in
 some places we stop passing the perag down the stack because the
 code enters into an as yet unconverted subsystem that still uses raw
 AGs.
 
 [Patches 11-16]
 
 These replace the agno passed in the btree cursor for per-ag btree
 operations with a perag that is passed to the cursor init function.
 The cursor takes it's own reference to the perag, and the reference
 is dropped when the cursor is deleted. Hence we get reference
 coverage for the entire time the cursor is active, even if the code
 that initialised the cursor drops it's reference before the cursor
 or any of it's children (duplicates) have been deleted.
 
 The first patch adds the perag infrastructure for the cursor, the
 next four patches convert a btree cursor at a time, and the last
 removes the agno from the cursor once it is unused.
 
 [Patches 17-21]
 
 These patches are a demonstration of the simplifications and
 cleanups that come from plumbing the perag through interfaces that
 select and then operate on a specific AG. In this case the inode
 allocation algorithm does up to three walks across all AGs before it
 either allocates an inode or fails. Two of these walks are purely
 just to select the AG, and even then it doesn't guarantee inode
 allocation success so there's a third walk if the selected AG
 allocation fails.
 
 These patches collapse the selection and allocation into a single
 loop, simplifies the error handling because xfs_dir_ialloc() always
 returns ENOSPC if no AG was selected for inode allocation or we fail
 to allocate an inode in any AG, gets rid of xfs_dir_ialloc()
 wrapper, converts inode allocation to run entirely from a single
 perag instance, and then factors xfs_dialloc() into a much, much
 simpler loop which is easy to understand.
 
 Hence we end up with the same inode allocation logic, but it only
 needs two complete iterations at worst, makes AG selection and
 allocation atomic w.r.t. shrink and chops out out over 100 lines of
 code from this hot code path.
 
 [Patch 22]
 
 Converts the unlink path to pass perags through it.
 
 There's more conversion work to be done, but this patchset gets
 through a large chunk of it in one hit. Most of the iterators are
 converted, so once this is solidified we can move on to converting
 these to active references for being able to free perags while the
 fs is still active.
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Merge tag 'xfs-perag-conv-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs into xfs-5.14-merge2

xfs: initial agnumber -> perag conversions for shrink

If we want to use active references to the perag to be able to gate
shrink removing AGs and hence perags safely, we've got a fair bit of
work to do actually use perags in all the places we need to.

There's a lot of code that iterates ag numbers and then
looks up perags from that, often multiple times for the same perag
in the one operation. If we want to use reference counted perags for
access control, then we need to convert all these uses to perag
iterators, not agno iterators.

[Patches 1-4]

The first step of this is consolidating all the perag management -
init, free, get, put, etc into a common location. THis is spread all
over the place right now, so move it all into libxfs/xfs_ag.[ch].
This does expose kernel only bits of the perag to libxfs and hence
userspace, so the structures and code is rearranged to minimise the
number of ifdefs that need to be added to the userspace codebase.
The perag iterator in xfs_icache.c is promoted to a first class API
and expanded to the needs of the code as required.

[Patches 5-10]

These are the first basic perag iterator conversions and changes to
pass the perag down the stack from those iterators where
appropriate. A lot of this is obvious, simple changes, though in
some places we stop passing the perag down the stack because the
code enters into an as yet unconverted subsystem that still uses raw
AGs.

[Patches 11-16]

These replace the agno passed in the btree cursor for per-ag btree
operations with a perag that is passed to the cursor init function.
The cursor takes it's own reference to the perag, and the reference
is dropped when the cursor is deleted. Hence we get reference
coverage for the entire time the cursor is active, even if the code
that initialised the cursor drops it's reference before the cursor
or any of it's children (duplicates) have been deleted.

The first patch adds the perag infrastructure for the cursor, the
next four patches convert a btree cursor at a time, and the last
removes the agno from the cursor once it is unused.

[Patches 17-21]

These patches are a demonstration of the simplifications and
cleanups that come from plumbing the perag through interfaces that
select and then operate on a specific AG. In this case the inode
allocation algorithm does up to three walks across all AGs before it
either allocates an inode or fails. Two of these walks are purely
just to select the AG, and even then it doesn't guarantee inode
allocation success so there's a third walk if the selected AG
allocation fails.

These patches collapse the selection and allocation into a single
loop, simplifies the error handling because xfs_dir_ialloc() always
returns ENOSPC if no AG was selected for inode allocation or we fail
to allocate an inode in any AG, gets rid of xfs_dir_ialloc()
wrapper, converts inode allocation to run entirely from a single
perag instance, and then factors xfs_dialloc() into a much, much
simpler loop which is easy to understand.

Hence we end up with the same inode allocation logic, but it only
needs two complete iterations at worst, makes AG selection and
allocation atomic w.r.t. shrink and chops out out over 100 lines of
code from this hot code path.

[Patch 22]

Converts the unlink path to pass perags through it.

There's more conversion work to be done, but this patchset gets
through a large chunk of it in one hit. Most of the iterators are
converted, so once this is solidified we can move on to converting
these to active references for being able to free perags while the
fs is still active.

* tag 'xfs-perag-conv-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (23 commits)
  xfs: remove xfs_perag_t
  xfs: use perag through unlink processing
  xfs: clean up and simplify xfs_dialloc()
  xfs: inode allocation can use a single perag instance
  xfs: get rid of xfs_dir_ialloc()
  xfs: collapse AG selection for inode allocation
  xfs: simplify xfs_dialloc_select_ag() return values
  xfs: remove agno from btree cursor
  xfs: use perag for ialloc btree cursors
  xfs: convert allocbt cursors to use perags
  xfs: convert refcount btree cursor to use perags
  xfs: convert rmap btree cursor to using a perag
  xfs: add a perag to the btree cursor
  xfs: pass perags around in fsmap data dev functions
  xfs: push perags through the ag reservation callouts
  xfs: pass perags through to the busy extent code
  xfs: convert secondary superblock walk to use perags
  xfs: convert xfs_iwalk to use perag references
  xfs: convert raw ag walks to use for_each_perag
  xfs: make for_each_perag... a first class citizen
  ...
2021-06-08 09:13:13 -07:00

896 lines
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_btree.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_icache.h"
#include "xfs_alloc.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc.h"
#include "xfs_ialloc_btree.h"
#include "xfs_refcount_btree.h"
#include "xfs_rmap.h"
#include "xfs_rmap_btree.h"
#include "xfs_log.h"
#include "xfs_trans_priv.h"
#include "xfs_attr.h"
#include "xfs_reflink.h"
#include "xfs_ag.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/repair.h"
#include "scrub/health.h"
/* Common code for the metadata scrubbers. */
/*
* Handling operational errors.
*
* The *_process_error() family of functions are used to process error return
* codes from functions called as part of a scrub operation.
*
* If there's no error, we return true to tell the caller that it's ok
* to move on to the next check in its list.
*
* For non-verifier errors (e.g. ENOMEM) we return false to tell the
* caller that something bad happened, and we preserve *error so that
* the caller can return the *error up the stack to userspace.
*
* Verifier errors (EFSBADCRC/EFSCORRUPTED) are recorded by setting
* OFLAG_CORRUPT in sm_flags and the *error is cleared. In other words,
* we track verifier errors (and failed scrub checks) via OFLAG_CORRUPT,
* not via return codes. We return false to tell the caller that
* something bad happened. Since the error has been cleared, the caller
* will (presumably) return that zero and scrubbing will move on to
* whatever's next.
*
* ftrace can be used to record the precise metadata location and the
* approximate code location of the failed operation.
*/
/* Check for operational errors. */
static bool
__xchk_process_error(
struct xfs_scrub *sc,
xfs_agnumber_t agno,
xfs_agblock_t bno,
int *error,
__u32 errflag,
void *ret_ip)
{
switch (*error) {
case 0:
return true;
case -EDEADLOCK:
/* Used to restart an op with deadlock avoidance. */
trace_xchk_deadlock_retry(
sc->ip ? sc->ip : XFS_I(file_inode(sc->file)),
sc->sm, *error);
break;
case -EFSBADCRC:
case -EFSCORRUPTED:
/* Note the badness but don't abort. */
sc->sm->sm_flags |= errflag;
*error = 0;
/* fall through */
default:
trace_xchk_op_error(sc, agno, bno, *error,
ret_ip);
break;
}
return false;
}
bool
xchk_process_error(
struct xfs_scrub *sc,
xfs_agnumber_t agno,
xfs_agblock_t bno,
int *error)
{
return __xchk_process_error(sc, agno, bno, error,
XFS_SCRUB_OFLAG_CORRUPT, __return_address);
}
bool
xchk_xref_process_error(
struct xfs_scrub *sc,
xfs_agnumber_t agno,
xfs_agblock_t bno,
int *error)
{
return __xchk_process_error(sc, agno, bno, error,
XFS_SCRUB_OFLAG_XFAIL, __return_address);
}
/* Check for operational errors for a file offset. */
static bool
__xchk_fblock_process_error(
struct xfs_scrub *sc,
int whichfork,
xfs_fileoff_t offset,
int *error,
__u32 errflag,
void *ret_ip)
{
switch (*error) {
case 0:
return true;
case -EDEADLOCK:
/* Used to restart an op with deadlock avoidance. */
trace_xchk_deadlock_retry(sc->ip, sc->sm, *error);
break;
case -EFSBADCRC:
case -EFSCORRUPTED:
/* Note the badness but don't abort. */
sc->sm->sm_flags |= errflag;
*error = 0;
/* fall through */
default:
trace_xchk_file_op_error(sc, whichfork, offset, *error,
ret_ip);
break;
}
return false;
}
bool
xchk_fblock_process_error(
struct xfs_scrub *sc,
int whichfork,
xfs_fileoff_t offset,
int *error)
{
return __xchk_fblock_process_error(sc, whichfork, offset, error,
XFS_SCRUB_OFLAG_CORRUPT, __return_address);
}
bool
xchk_fblock_xref_process_error(
struct xfs_scrub *sc,
int whichfork,
xfs_fileoff_t offset,
int *error)
{
return __xchk_fblock_process_error(sc, whichfork, offset, error,
XFS_SCRUB_OFLAG_XFAIL, __return_address);
}
/*
* Handling scrub corruption/optimization/warning checks.
*
* The *_set_{corrupt,preen,warning}() family of functions are used to
* record the presence of metadata that is incorrect (corrupt), could be
* optimized somehow (preen), or should be flagged for administrative
* review but is not incorrect (warn).
*
* ftrace can be used to record the precise metadata location and
* approximate code location of the failed check.
*/
/* Record a block which could be optimized. */
void
xchk_block_set_preen(
struct xfs_scrub *sc,
struct xfs_buf *bp)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN;
trace_xchk_block_preen(sc, bp->b_bn, __return_address);
}
/*
* Record an inode which could be optimized. The trace data will
* include the block given by bp if bp is given; otherwise it will use
* the block location of the inode record itself.
*/
void
xchk_ino_set_preen(
struct xfs_scrub *sc,
xfs_ino_t ino)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN;
trace_xchk_ino_preen(sc, ino, __return_address);
}
/* Record something being wrong with the filesystem primary superblock. */
void
xchk_set_corrupt(
struct xfs_scrub *sc)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
trace_xchk_fs_error(sc, 0, __return_address);
}
/* Record a corrupt block. */
void
xchk_block_set_corrupt(
struct xfs_scrub *sc,
struct xfs_buf *bp)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
trace_xchk_block_error(sc, bp->b_bn, __return_address);
}
/* Record a corruption while cross-referencing. */
void
xchk_block_xref_set_corrupt(
struct xfs_scrub *sc,
struct xfs_buf *bp)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT;
trace_xchk_block_error(sc, bp->b_bn, __return_address);
}
/*
* Record a corrupt inode. The trace data will include the block given
* by bp if bp is given; otherwise it will use the block location of the
* inode record itself.
*/
void
xchk_ino_set_corrupt(
struct xfs_scrub *sc,
xfs_ino_t ino)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
trace_xchk_ino_error(sc, ino, __return_address);
}
/* Record a corruption while cross-referencing with an inode. */
void
xchk_ino_xref_set_corrupt(
struct xfs_scrub *sc,
xfs_ino_t ino)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT;
trace_xchk_ino_error(sc, ino, __return_address);
}
/* Record corruption in a block indexed by a file fork. */
void
xchk_fblock_set_corrupt(
struct xfs_scrub *sc,
int whichfork,
xfs_fileoff_t offset)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
trace_xchk_fblock_error(sc, whichfork, offset, __return_address);
}
/* Record a corruption while cross-referencing a fork block. */
void
xchk_fblock_xref_set_corrupt(
struct xfs_scrub *sc,
int whichfork,
xfs_fileoff_t offset)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT;
trace_xchk_fblock_error(sc, whichfork, offset, __return_address);
}
/*
* Warn about inodes that need administrative review but is not
* incorrect.
*/
void
xchk_ino_set_warning(
struct xfs_scrub *sc,
xfs_ino_t ino)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_WARNING;
trace_xchk_ino_warning(sc, ino, __return_address);
}
/* Warn about a block indexed by a file fork that needs review. */
void
xchk_fblock_set_warning(
struct xfs_scrub *sc,
int whichfork,
xfs_fileoff_t offset)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_WARNING;
trace_xchk_fblock_warning(sc, whichfork, offset, __return_address);
}
/* Signal an incomplete scrub. */
void
xchk_set_incomplete(
struct xfs_scrub *sc)
{
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_INCOMPLETE;
trace_xchk_incomplete(sc, __return_address);
}
/*
* rmap scrubbing -- compute the number of blocks with a given owner,
* at least according to the reverse mapping data.
*/
struct xchk_rmap_ownedby_info {
const struct xfs_owner_info *oinfo;
xfs_filblks_t *blocks;
};
STATIC int
xchk_count_rmap_ownedby_irec(
struct xfs_btree_cur *cur,
struct xfs_rmap_irec *rec,
void *priv)
{
struct xchk_rmap_ownedby_info *sroi = priv;
bool irec_attr;
bool oinfo_attr;
irec_attr = rec->rm_flags & XFS_RMAP_ATTR_FORK;
oinfo_attr = sroi->oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK;
if (rec->rm_owner != sroi->oinfo->oi_owner)
return 0;
if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) || irec_attr == oinfo_attr)
(*sroi->blocks) += rec->rm_blockcount;
return 0;
}
/*
* Calculate the number of blocks the rmap thinks are owned by something.
* The caller should pass us an rmapbt cursor.
*/
int
xchk_count_rmap_ownedby_ag(
struct xfs_scrub *sc,
struct xfs_btree_cur *cur,
const struct xfs_owner_info *oinfo,
xfs_filblks_t *blocks)
{
struct xchk_rmap_ownedby_info sroi = {
.oinfo = oinfo,
.blocks = blocks,
};
*blocks = 0;
return xfs_rmap_query_all(cur, xchk_count_rmap_ownedby_irec,
&sroi);
}
/*
* AG scrubbing
*
* These helpers facilitate locking an allocation group's header
* buffers, setting up cursors for all btrees that are present, and
* cleaning everything up once we're through.
*/
/* Decide if we want to return an AG header read failure. */
static inline bool
want_ag_read_header_failure(
struct xfs_scrub *sc,
unsigned int type)
{
/* Return all AG header read failures when scanning btrees. */
if (sc->sm->sm_type != XFS_SCRUB_TYPE_AGF &&
sc->sm->sm_type != XFS_SCRUB_TYPE_AGFL &&
sc->sm->sm_type != XFS_SCRUB_TYPE_AGI)
return true;
/*
* If we're scanning a given type of AG header, we only want to
* see read failures from that specific header. We'd like the
* other headers to cross-check them, but this isn't required.
*/
if (sc->sm->sm_type == type)
return true;
return false;
}
/*
* Grab all the headers for an AG.
*
* The headers should be released by xchk_ag_free, but as a fail
* safe we attach all the buffers we grab to the scrub transaction so
* they'll all be freed when we cancel it.
*/
int
xchk_ag_read_headers(
struct xfs_scrub *sc,
xfs_agnumber_t agno,
struct xchk_ag *sa)
{
struct xfs_mount *mp = sc->mp;
int error;
sa->agno = agno;
error = xfs_ialloc_read_agi(mp, sc->tp, agno, &sa->agi_bp);
if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGI))
goto out;
error = xfs_alloc_read_agf(mp, sc->tp, agno, 0, &sa->agf_bp);
if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGF))
goto out;
error = xfs_alloc_read_agfl(mp, sc->tp, agno, &sa->agfl_bp);
if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGFL))
goto out;
error = 0;
out:
return error;
}
/* Release all the AG btree cursors. */
void
xchk_ag_btcur_free(
struct xchk_ag *sa)
{
if (sa->refc_cur)
xfs_btree_del_cursor(sa->refc_cur, XFS_BTREE_ERROR);
if (sa->rmap_cur)
xfs_btree_del_cursor(sa->rmap_cur, XFS_BTREE_ERROR);
if (sa->fino_cur)
xfs_btree_del_cursor(sa->fino_cur, XFS_BTREE_ERROR);
if (sa->ino_cur)
xfs_btree_del_cursor(sa->ino_cur, XFS_BTREE_ERROR);
if (sa->cnt_cur)
xfs_btree_del_cursor(sa->cnt_cur, XFS_BTREE_ERROR);
if (sa->bno_cur)
xfs_btree_del_cursor(sa->bno_cur, XFS_BTREE_ERROR);
sa->refc_cur = NULL;
sa->rmap_cur = NULL;
sa->fino_cur = NULL;
sa->ino_cur = NULL;
sa->bno_cur = NULL;
sa->cnt_cur = NULL;
}
/* Initialize all the btree cursors for an AG. */
void
xchk_ag_btcur_init(
struct xfs_scrub *sc,
struct xchk_ag *sa)
{
struct xfs_mount *mp = sc->mp;
xchk_perag_get(sc->mp, sa);
if (sa->agf_bp &&
xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_BNO)) {
/* Set up a bnobt cursor for cross-referencing. */
sa->bno_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
sa->pag, XFS_BTNUM_BNO);
}
if (sa->agf_bp &&
xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_CNT)) {
/* Set up a cntbt cursor for cross-referencing. */
sa->cnt_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
sa->pag, XFS_BTNUM_CNT);
}
/* Set up a inobt cursor for cross-referencing. */
if (sa->agi_bp &&
xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_INO)) {
sa->ino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
sa->pag, XFS_BTNUM_INO);
}
/* Set up a finobt cursor for cross-referencing. */
if (sa->agi_bp && xfs_sb_version_hasfinobt(&mp->m_sb) &&
xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_FINO)) {
sa->fino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
sa->pag, XFS_BTNUM_FINO);
}
/* Set up a rmapbt cursor for cross-referencing. */
if (sa->agf_bp && xfs_sb_version_hasrmapbt(&mp->m_sb) &&
xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_RMAP)) {
sa->rmap_cur = xfs_rmapbt_init_cursor(mp, sc->tp, sa->agf_bp,
sa->pag);
}
/* Set up a refcountbt cursor for cross-referencing. */
if (sa->agf_bp && xfs_sb_version_hasreflink(&mp->m_sb) &&
xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_REFC)) {
sa->refc_cur = xfs_refcountbt_init_cursor(mp, sc->tp,
sa->agf_bp, sa->pag);
}
}
/* Release the AG header context and btree cursors. */
void
xchk_ag_free(
struct xfs_scrub *sc,
struct xchk_ag *sa)
{
xchk_ag_btcur_free(sa);
if (sa->agfl_bp) {
xfs_trans_brelse(sc->tp, sa->agfl_bp);
sa->agfl_bp = NULL;
}
if (sa->agf_bp) {
xfs_trans_brelse(sc->tp, sa->agf_bp);
sa->agf_bp = NULL;
}
if (sa->agi_bp) {
xfs_trans_brelse(sc->tp, sa->agi_bp);
sa->agi_bp = NULL;
}
if (sa->pag) {
xfs_perag_put(sa->pag);
sa->pag = NULL;
}
sa->agno = NULLAGNUMBER;
}
/*
* For scrub, grab the AGI and the AGF headers, in that order. Locking
* order requires us to get the AGI before the AGF. We use the
* transaction to avoid deadlocking on crosslinked metadata buffers;
* either the caller passes one in (bmap scrub) or we have to create a
* transaction ourselves.
*/
int
xchk_ag_init(
struct xfs_scrub *sc,
xfs_agnumber_t agno,
struct xchk_ag *sa)
{
int error;
error = xchk_ag_read_headers(sc, agno, sa);
if (error)
return error;
xchk_ag_btcur_init(sc, sa);
return 0;
}
/*
* Grab the per-ag structure if we haven't already gotten it. Teardown of the
* xchk_ag will release it for us.
*/
void
xchk_perag_get(
struct xfs_mount *mp,
struct xchk_ag *sa)
{
if (!sa->pag)
sa->pag = xfs_perag_get(mp, sa->agno);
}
/* Per-scrubber setup functions */
/*
* Grab an empty transaction so that we can re-grab locked buffers if
* one of our btrees turns out to be cyclic.
*
* If we're going to repair something, we need to ask for the largest possible
* log reservation so that we can handle the worst case scenario for metadata
* updates while rebuilding a metadata item. We also need to reserve as many
* blocks in the head transaction as we think we're going to need to rebuild
* the metadata object.
*/
int
xchk_trans_alloc(
struct xfs_scrub *sc,
uint resblks)
{
if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
return xfs_trans_alloc(sc->mp, &M_RES(sc->mp)->tr_itruncate,
resblks, 0, 0, &sc->tp);
return xfs_trans_alloc_empty(sc->mp, &sc->tp);
}
/* Set us up with a transaction and an empty context. */
int
xchk_setup_fs(
struct xfs_scrub *sc)
{
uint resblks;
resblks = xrep_calc_ag_resblks(sc);
return xchk_trans_alloc(sc, resblks);
}
/* Set us up with AG headers and btree cursors. */
int
xchk_setup_ag_btree(
struct xfs_scrub *sc,
bool force_log)
{
struct xfs_mount *mp = sc->mp;
int error;
/*
* If the caller asks us to checkpont the log, do so. This
* expensive operation should be performed infrequently and only
* as a last resort. Any caller that sets force_log should
* document why they need to do so.
*/
if (force_log) {
error = xchk_checkpoint_log(mp);
if (error)
return error;
}
error = xchk_setup_fs(sc);
if (error)
return error;
return xchk_ag_init(sc, sc->sm->sm_agno, &sc->sa);
}
/* Push everything out of the log onto disk. */
int
xchk_checkpoint_log(
struct xfs_mount *mp)
{
int error;
error = xfs_log_force(mp, XFS_LOG_SYNC);
if (error)
return error;
xfs_ail_push_all_sync(mp->m_ail);
return 0;
}
/*
* Given an inode and the scrub control structure, grab either the
* inode referenced in the control structure or the inode passed in.
* The inode is not locked.
*/
int
xchk_get_inode(
struct xfs_scrub *sc)
{
struct xfs_imap imap;
struct xfs_mount *mp = sc->mp;
struct xfs_inode *ip_in = XFS_I(file_inode(sc->file));
struct xfs_inode *ip = NULL;
int error;
/* We want to scan the inode we already had opened. */
if (sc->sm->sm_ino == 0 || sc->sm->sm_ino == ip_in->i_ino) {
sc->ip = ip_in;
return 0;
}
/* Look up the inode, see if the generation number matches. */
if (xfs_internal_inum(mp, sc->sm->sm_ino))
return -ENOENT;
error = xfs_iget(mp, NULL, sc->sm->sm_ino,
XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE, 0, &ip);
switch (error) {
case -ENOENT:
/* Inode doesn't exist, just bail out. */
return error;
case 0:
/* Got an inode, continue. */
break;
case -EINVAL:
/*
* -EINVAL with IGET_UNTRUSTED could mean one of several
* things: userspace gave us an inode number that doesn't
* correspond to fs space, or doesn't have an inobt entry;
* or it could simply mean that the inode buffer failed the
* read verifiers.
*
* Try just the inode mapping lookup -- if it succeeds, then
* the inode buffer verifier failed and something needs fixing.
* Otherwise, we really couldn't find it so tell userspace
* that it no longer exists.
*/
error = xfs_imap(sc->mp, sc->tp, sc->sm->sm_ino, &imap,
XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE);
if (error)
return -ENOENT;
error = -EFSCORRUPTED;
/* fall through */
default:
trace_xchk_op_error(sc,
XFS_INO_TO_AGNO(mp, sc->sm->sm_ino),
XFS_INO_TO_AGBNO(mp, sc->sm->sm_ino),
error, __return_address);
return error;
}
if (VFS_I(ip)->i_generation != sc->sm->sm_gen) {
xfs_irele(ip);
return -ENOENT;
}
sc->ip = ip;
return 0;
}
/* Set us up to scrub a file's contents. */
int
xchk_setup_inode_contents(
struct xfs_scrub *sc,
unsigned int resblks)
{
int error;
error = xchk_get_inode(sc);
if (error)
return error;
/* Got the inode, lock it and we're ready to go. */
sc->ilock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
xfs_ilock(sc->ip, sc->ilock_flags);
error = xchk_trans_alloc(sc, resblks);
if (error)
goto out;
sc->ilock_flags |= XFS_ILOCK_EXCL;
xfs_ilock(sc->ip, XFS_ILOCK_EXCL);
out:
/* scrub teardown will unlock and release the inode for us */
return error;
}
/*
* Predicate that decides if we need to evaluate the cross-reference check.
* If there was an error accessing the cross-reference btree, just delete
* the cursor and skip the check.
*/
bool
xchk_should_check_xref(
struct xfs_scrub *sc,
int *error,
struct xfs_btree_cur **curpp)
{
/* No point in xref if we already know we're corrupt. */
if (xchk_skip_xref(sc->sm))
return false;
if (*error == 0)
return true;
if (curpp) {
/* If we've already given up on xref, just bail out. */
if (!*curpp)
return false;
/* xref error, delete cursor and bail out. */
xfs_btree_del_cursor(*curpp, XFS_BTREE_ERROR);
*curpp = NULL;
}
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XFAIL;
trace_xchk_xref_error(sc, *error, __return_address);
/*
* Errors encountered during cross-referencing with another
* data structure should not cause this scrubber to abort.
*/
*error = 0;
return false;
}
/* Run the structure verifiers on in-memory buffers to detect bad memory. */
void
xchk_buffer_recheck(
struct xfs_scrub *sc,
struct xfs_buf *bp)
{
xfs_failaddr_t fa;
if (bp->b_ops == NULL) {
xchk_block_set_corrupt(sc, bp);
return;
}
if (bp->b_ops->verify_struct == NULL) {
xchk_set_incomplete(sc);
return;
}
fa = bp->b_ops->verify_struct(bp);
if (!fa)
return;
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
trace_xchk_block_error(sc, bp->b_bn, fa);
}
/*
* Scrub the attr/data forks of a metadata inode. The metadata inode must be
* pointed to by sc->ip and the ILOCK must be held.
*/
int
xchk_metadata_inode_forks(
struct xfs_scrub *sc)
{
__u32 smtype;
bool shared;
int error;
if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
return 0;
/* Metadata inodes don't live on the rt device. */
if (sc->ip->i_diflags & XFS_DIFLAG_REALTIME) {
xchk_ino_set_corrupt(sc, sc->ip->i_ino);
return 0;
}
/* They should never participate in reflink. */
if (xfs_is_reflink_inode(sc->ip)) {
xchk_ino_set_corrupt(sc, sc->ip->i_ino);
return 0;
}
/* They also should never have extended attributes. */
if (xfs_inode_hasattr(sc->ip)) {
xchk_ino_set_corrupt(sc, sc->ip->i_ino);
return 0;
}
/* Invoke the data fork scrubber. */
smtype = sc->sm->sm_type;
sc->sm->sm_type = XFS_SCRUB_TYPE_BMBTD;
error = xchk_bmap_data(sc);
sc->sm->sm_type = smtype;
if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
return error;
/* Look for incorrect shared blocks. */
if (xfs_sb_version_hasreflink(&sc->mp->m_sb)) {
error = xfs_reflink_inode_has_shared_extents(sc->tp, sc->ip,
&shared);
if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0,
&error))
return error;
if (shared)
xchk_ino_set_corrupt(sc, sc->ip->i_ino);
}
return error;
}
/*
* Try to lock an inode in violation of the usual locking order rules. For
* example, trying to get the IOLOCK while in transaction context, or just
* plain breaking AG-order or inode-order inode locking rules. Either way,
* the only way to avoid an ABBA deadlock is to use trylock and back off if
* we can't.
*/
int
xchk_ilock_inverted(
struct xfs_inode *ip,
uint lock_mode)
{
int i;
for (i = 0; i < 20; i++) {
if (xfs_ilock_nowait(ip, lock_mode))
return 0;
delay(1);
}
return -EDEADLOCK;
}
/* Pause background reaping of resources. */
void
xchk_stop_reaping(
struct xfs_scrub *sc)
{
sc->flags |= XCHK_REAPING_DISABLED;
xfs_blockgc_stop(sc->mp);
}
/* Restart background reaping of resources. */
void
xchk_start_reaping(
struct xfs_scrub *sc)
{
xfs_blockgc_start(sc->mp);
sc->flags &= ~XCHK_REAPING_DISABLED;
}
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