Re: [PATCH 03/27] xfs: create an ioctl to scrub AG metadata

[Brian Foster <bfoster@redhat.com>]

On Wed, Sep 20, 2017 at 05:17:56PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Create an ioctl that can be used to scrub internal filesystem metadata.
> The new ioctl takes the metadata type, an (optional) AG number, an
> (optional) inode number and generation, and a flags argument.  This will
> be used by the upcoming XFS online scrub tool.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/Kconfig           |   17 ++++++++++++++
>  fs/xfs/Makefile          |   11 +++++++++
>  fs/xfs/libxfs/xfs_fs.h   |   53 +++++++++++++++++++++++++++++++++++++++++++++
>  fs/xfs/scrub/scrub.c     |   54 ++++++++++++++++++++++++++++++++++++++++++++++
>  fs/xfs/scrub/scrub.h     |   25 +++++++++++++++++++++
>  fs/xfs/scrub/trace.c     |   41 +++++++++++++++++++++++++++++++++++
>  fs/xfs/scrub/trace.h     |   33 ++++++++++++++++++++++++++++
>  fs/xfs/scrub/xfs_scrub.h |   29 +++++++++++++++++++++++++
>  fs/xfs/xfs_ioctl.c       |   28 ++++++++++++++++++++++++
>  fs/xfs/xfs_ioctl32.c     |    1 +
>  10 files changed, 292 insertions(+)
>  create mode 100644 fs/xfs/scrub/scrub.c
>  create mode 100644 fs/xfs/scrub/scrub.h
>  create mode 100644 fs/xfs/scrub/trace.c
>  create mode 100644 fs/xfs/scrub/trace.h
>  create mode 100644 fs/xfs/scrub/xfs_scrub.h
> 
> 

The code looks sane, though I think I need to understand the error codes
a bit better. Perhaps once I get further into the series..

Brian

> diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig
> index 1b98cfa..f42fcf1 100644
> --- a/fs/xfs/Kconfig
> +++ b/fs/xfs/Kconfig
> @@ -71,6 +71,23 @@ config XFS_RT
>  
>  	  If unsure, say N.
>  
> +config XFS_ONLINE_SCRUB
> +	bool "XFS online metadata check support"
> +	default n
> +	depends on XFS_FS
> +	help
> +	  If you say Y here you will be able to check metadata on a
> +	  mounted XFS filesystem.  This feature is intended to reduce
> +	  filesystem downtime by supplementing xfs_repair.  The key
> +	  advantage here is to look for problems proactively so that
> +	  they can be dealt with in a controlled manner.
> +
> +	  This feature is considered EXPERIMENTAL.  Use with caution!
> +
> +	  See the xfs_scrub man page in section 8 for additional information.
> +
> +	  If unsure, say N.
> +
>  config XFS_WARN
>  	bool "XFS Verbose Warnings"
>  	depends on XFS_FS && !XFS_DEBUG
> diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
> index dbc33e0..f4312bc 100644
> --- a/fs/xfs/Makefile
> +++ b/fs/xfs/Makefile
> @@ -138,3 +138,14 @@ xfs-$(CONFIG_XFS_POSIX_ACL)	+= xfs_acl.o
>  xfs-$(CONFIG_SYSCTL)		+= xfs_sysctl.o
>  xfs-$(CONFIG_COMPAT)		+= xfs_ioctl32.o
>  xfs-$(CONFIG_EXPORTFS_BLOCK_OPS)	+= xfs_pnfs.o
> +
> +# online scrub/repair
> +ifeq ($(CONFIG_XFS_ONLINE_SCRUB),y)
> +
> +# Tracepoints like to blow up, so build that before everything else
> +
> +xfs-y				+= $(addprefix scrub/, \
> +				   trace.o \
> +				   scrub.o \
> +				   )
> +endif
> diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
> index 2c26c38..a4b4c8c 100644
> --- a/fs/xfs/libxfs/xfs_fs.h
> +++ b/fs/xfs/libxfs/xfs_fs.h
> @@ -468,6 +468,58 @@ typedef struct xfs_swapext
>  #define XFS_FSOP_GOING_FLAGS_LOGFLUSH		0x1	/* flush log but not data */
>  #define XFS_FSOP_GOING_FLAGS_NOLOGFLUSH		0x2	/* don't flush log nor data */
>  
> +/* metadata scrubbing */
> +struct xfs_scrub_metadata {
> +	__u32 sm_type;		/* What to check? */
> +	__u32 sm_flags;		/* flags; see below. */
> +	__u64 sm_ino;		/* inode number. */
> +	__u32 sm_gen;		/* inode generation. */
> +	__u32 sm_agno;		/* ag number. */
> +	__u64 sm_reserved[5];	/* pad to 64 bytes */
> +};
> +
> +/*
> + * Metadata types and flags for scrub operation.
> + */
> +
> +/* Scrub subcommands. */
> +
> +/* Number of scrub subcommands. */
> +#define XFS_SCRUB_TYPE_NR	0
> +
> +/* i: Repair this metadata. */
> +#define XFS_SCRUB_IFLAG_REPAIR		(1 << 0)
> +
> +/* o: Metadata object needs repair. */
> +#define XFS_SCRUB_OFLAG_CORRUPT		(1 << 1)
> +
> +/*
> + * o: Metadata object could be optimized.  It's not corrupt, but
> + *    we could improve on it somehow.
> + */
> +#define XFS_SCRUB_OFLAG_PREEN		(1 << 2)
> +
> +/* o: Cross-referencing failed. */
> +#define XFS_SCRUB_OFLAG_XFAIL		(1 << 3)
> +
> +/* o: Metadata object disagrees with cross-referenced metadata. */
> +#define XFS_SCRUB_OFLAG_XCORRUPT	(1 << 4)
> +
> +/* o: Scan was not complete. */
> +#define XFS_SCRUB_OFLAG_INCOMPLETE	(1 << 5)
> +
> +/* o: Metadata object looked funny but isn't corrupt. */
> +#define XFS_SCRUB_OFLAG_WARNING		(1 << 6)
> +
> +#define XFS_SCRUB_FLAGS_IN	(XFS_SCRUB_IFLAG_REPAIR)
> +#define XFS_SCRUB_FLAGS_OUT	(XFS_SCRUB_OFLAG_CORRUPT | \
> +				 XFS_SCRUB_OFLAG_PREEN | \
> +				 XFS_SCRUB_OFLAG_XFAIL | \
> +				 XFS_SCRUB_OFLAG_XCORRUPT | \
> +				 XFS_SCRUB_OFLAG_INCOMPLETE | \
> +				 XFS_SCRUB_OFLAG_WARNING)
> +#define XFS_SCRUB_FLAGS_ALL	(XFS_SCRUB_FLAGS_IN | XFS_SCRUB_FLAGS_OUT)
> +
>  /*
>   * AG reserved block counters
>   */
> @@ -522,6 +574,7 @@ struct xfs_fsop_ag_resblks {
>  #define XFS_IOC_ZERO_RANGE	_IOW ('X', 57, struct xfs_flock64)
>  #define XFS_IOC_FREE_EOFBLOCKS	_IOR ('X', 58, struct xfs_fs_eofblocks)
>  /*	XFS_IOC_GETFSMAP ------ hoisted 59         */
> +#define XFS_IOC_SCRUB_METADATA	_IOWR('X', 60, struct xfs_scrub_metadata)
>  
>  /*
>   * ioctl commands that replace IRIX syssgi()'s
> diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
> new file mode 100644
> index 0000000..5db2a6f
> --- /dev/null
> +++ b/fs/xfs/scrub/scrub.c
> @@ -0,0 +1,54 @@
> +/*
> + * 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/trace.h"
> +
> +/* Dispatch metadata scrubbing. */
> +int
> +xfs_scrub_metadata(
> +	struct xfs_inode		*ip,
> +	struct xfs_scrub_metadata	*sm)
> +{
> +	return -EOPNOTSUPP;
> +}
> diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
> new file mode 100644
> index 0000000..eb1cd9d
> --- /dev/null
> +++ b/fs/xfs/scrub/scrub.h
> @@ -0,0 +1,25 @@
> +/*
> + * 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_SCRUB_H__
> +#define __XFS_SCRUB_SCRUB_H__
> +
> +/* Metadata scrubbers */
> +
> +#endif	/* __XFS_SCRUB_SCRUB_H__ */
> diff --git a/fs/xfs/scrub/trace.c b/fs/xfs/scrub/trace.c
> new file mode 100644
> index 0000000..c59fd41
> --- /dev/null
> +++ b/fs/xfs/scrub/trace.c
> @@ -0,0 +1,41 @@
> +/*
> + * 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_log_format.h"
> +#include "xfs_trans_resv.h"
> +#include "xfs_mount.h"
> +#include "xfs_defer.h"
> +#include "xfs_da_format.h"
> +#include "xfs_defer.h"
> +#include "xfs_inode.h"
> +#include "xfs_btree.h"
> +#include "xfs_trans.h"
> +#include "scrub/xfs_scrub.h"
> +#include "scrub/scrub.h"
> +
> +/*
> + * We include this last to have the helpers above available for the trace
> + * event implementations.
> + */
> +#define CREATE_TRACE_POINTS
> +#include "scrub/trace.h"
> diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
> new file mode 100644
> index 0000000..a95a7c8
> --- /dev/null
> +++ b/fs/xfs/scrub/trace.h
> @@ -0,0 +1,33 @@
> +/*
> + * 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.
> + */
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM xfs_scrub
> +
> +#if !defined(_TRACE_XFS_SCRUB_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_XFS_SCRUB_TRACE_H
> +
> +#include <linux/tracepoint.h>
> +
> +#endif /* _TRACE_XFS_SCRUB_TRACE_H */
> +
> +#undef TRACE_INCLUDE_PATH
> +#define TRACE_INCLUDE_PATH .
> +#define TRACE_INCLUDE_FILE scrub/trace
> +#include <trace/define_trace.h>
> diff --git a/fs/xfs/scrub/xfs_scrub.h b/fs/xfs/scrub/xfs_scrub.h
> new file mode 100644
> index 0000000..e00e0ea
> --- /dev/null
> +++ b/fs/xfs/scrub/xfs_scrub.h
> @@ -0,0 +1,29 @@
> +/*
> + * 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_H__
> +#define __XFS_SCRUB_H__
> +
> +#ifndef CONFIG_XFS_ONLINE_SCRUB
> +# define xfs_scrub_metadata(ip, sm)	(-ENOTTY)
> +#else
> +int xfs_scrub_metadata(struct xfs_inode *ip, struct xfs_scrub_metadata *sm);
> +#endif /* CONFIG_XFS_ONLINE_SCRUB */
> +
> +#endif	/* __XFS_SCRUB_H__ */
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 44dc178..ab7a7f8 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -44,6 +44,7 @@
>  #include "xfs_btree.h"
>  #include <linux/fsmap.h>
>  #include "xfs_fsmap.h"
> +#include "scrub/xfs_scrub.h"
>  
>  #include <linux/capability.h>
>  #include <linux/cred.h>
> @@ -1702,6 +1703,30 @@ xfs_ioc_getfsmap(
>  	return 0;
>  }
>  
> +STATIC int
> +xfs_ioc_scrub_metadata(
> +	struct xfs_inode		*ip,
> +	void				__user *arg)
> +{
> +	struct xfs_scrub_metadata	scrub;
> +	int				error;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +
> +	if (copy_from_user(&scrub, arg, sizeof(scrub)))
> +		return -EFAULT;
> +
> +	error = xfs_scrub_metadata(ip, &scrub);
> +	if (error)
> +		return error;
> +
> +	if (copy_to_user(arg, &scrub, sizeof(scrub)))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>  int
>  xfs_ioc_swapext(
>  	xfs_swapext_t	*sxp)
> @@ -1906,6 +1931,9 @@ xfs_file_ioctl(
>  	case FS_IOC_GETFSMAP:
>  		return xfs_ioc_getfsmap(ip, arg);
>  
> +	case XFS_IOC_SCRUB_METADATA:
> +		return xfs_ioc_scrub_metadata(ip, arg);
> +
>  	case XFS_IOC_FD_TO_HANDLE:
>  	case XFS_IOC_PATH_TO_HANDLE:
>  	case XFS_IOC_PATH_TO_FSHANDLE: {
> diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
> index e8b4de3..972d4bd 100644
> --- a/fs/xfs/xfs_ioctl32.c
> +++ b/fs/xfs/xfs_ioctl32.c
> @@ -557,6 +557,7 @@ xfs_file_compat_ioctl(
>  	case XFS_IOC_ERROR_CLEARALL:
>  	case FS_IOC_GETFSMAP:
>  	case XFS_IOC_GET_AG_RESBLKS:
> +	case XFS_IOC_SCRUB_METADATA:
>  		return xfs_file_ioctl(filp, cmd, p);
>  #ifndef BROKEN_X86_ALIGNMENT
>  	/* These are handled fine if no alignment issues */
> 
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