xfs: probe the scrub ioctl

Create a probe scrubber with id 0.  This will be used by xfs_scrub to
probe the kernel's abilities to scrub (and repair) the metadata.  We do
this by validating the ioctl inputs from userspace, preparing the
filesystem for a scrub (or a repair) operation, and immediately
returning to userspace.  Userspace can use the returned errno and
structure state to decide (in broad terms) if scrub/repair are
supported by the running kernel.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Darrick J. Wong 2017-10-17 21:37:36 -07:00
parent a56371865e
commit dcb660f922
7 changed files with 150 additions and 1 deletions

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@ -143,6 +143,7 @@ ifeq ($(CONFIG_XFS_ONLINE_SCRUB),y)
xfs-y += $(addprefix scrub/, \
trace.o \
common.o \
scrub.o \
)
endif

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@ -483,9 +483,10 @@ struct xfs_scrub_metadata {
*/
/* Scrub subcommands. */
#define XFS_SCRUB_TYPE_PROBE 0 /* presence test ioctl */
/* Number of scrub subcommands. */
#define XFS_SCRUB_TYPE_NR 0
#define XFS_SCRUB_TYPE_NR 1
/* i: Repair this metadata. */
#define XFS_SCRUB_IFLAG_REPAIR (1 << 0)

59
fs/xfs/scrub/common.c Normal file
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@ -0,0 +1,59 @@
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#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_defer.h"
#include "xfs_btree.h"
#include "xfs_bit.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_inode.h"
#include "xfs_alloc.h"
#include "xfs_alloc_btree.h"
#include "xfs_bmap.h"
#include "xfs_bmap_btree.h"
#include "xfs_ialloc.h"
#include "xfs_ialloc_btree.h"
#include "xfs_refcount.h"
#include "xfs_refcount_btree.h"
#include "xfs_rmap.h"
#include "xfs_rmap_btree.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
/* Common code for the metadata scrubbers. */
/* Per-scrubber setup functions */
/* Set us up with a transaction and an empty context. */
int
xfs_scrub_setup_fs(
struct xfs_scrub_context *sc,
struct xfs_inode *ip)
{
return xfs_scrub_trans_alloc(sc->sm, sc->mp, &sc->tp);
}

57
fs/xfs/scrub/common.h Normal file
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@ -0,0 +1,57 @@
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef __XFS_SCRUB_COMMON_H__
#define __XFS_SCRUB_COMMON_H__
/*
* We /could/ terminate a scrub/repair operation early. If we're not
* in a good place to continue (fatal signal, etc.) then bail out.
* Note that we're careful not to make any judgements about *error.
*/
static inline bool
xfs_scrub_should_terminate(
struct xfs_scrub_context *sc,
int *error)
{
if (fatal_signal_pending(current)) {
if (*error == 0)
*error = -EAGAIN;
return true;
}
return false;
}
/*
* Grab an empty transaction so that we can re-grab locked buffers if
* one of our btrees turns out to be cyclic.
*/
static inline int
xfs_scrub_trans_alloc(
struct xfs_scrub_metadata *sm,
struct xfs_mount *mp,
struct xfs_trans **tpp)
{
return xfs_trans_alloc_empty(mp, tpp);
}
/* Setup functions */
int xfs_scrub_setup_fs(struct xfs_scrub_context *sc, struct xfs_inode *ip);
#endif /* __XFS_SCRUB_COMMON_H__ */

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@ -42,6 +42,7 @@
#include "xfs_rmap_btree.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
/*
@ -108,6 +109,30 @@
* will be set.
*/
/*
* Scrub probe -- userspace uses this to probe if we're willing to scrub
* or repair a given mountpoint. This will be used by xfs_scrub to
* probe the kernel's abilities to scrub (and repair) the metadata. We
* do this by validating the ioctl inputs from userspace, preparing the
* filesystem for a scrub (or a repair) operation, and immediately
* returning to userspace. Userspace can use the returned errno and
* structure state to decide (in broad terms) if scrub/repair are
* supported by the running kernel.
*/
int
xfs_scrub_probe(
struct xfs_scrub_context *sc)
{
int error = 0;
if (sc->sm->sm_ino || sc->sm->sm_agno)
return -EINVAL;
if (xfs_scrub_should_terminate(sc, &error))
return error;
return 0;
}
/* Scrub setup and teardown */
/* Free all the resources and finish the transactions. */
@ -126,6 +151,10 @@ xfs_scrub_teardown(
/* Scrubbing dispatch. */
static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
{ /* ioctl presence test */
.setup = xfs_scrub_setup_fs,
.scrub = xfs_scrub_probe,
},
};
/* This isn't a stable feature, warn once per day. */

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@ -45,5 +45,6 @@ struct xfs_scrub_context {
};
/* Metadata scrubbers */
int xfs_scrub_tester(struct xfs_scrub_context *sc);
#endif /* __XFS_SCRUB_SCRUB_H__ */

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@ -32,6 +32,7 @@
#include "xfs_trans.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
/*
* We include this last to have the helpers above available for the trace