xfs: online scrub support

From: Darrick J. Wong <[email protected]>

For an XFS_IGET_INCORE iget operation, if the inode isn't in the cache, return ENODATA so that we don't confuse it with the pre-existing ENOENT cases (inode is in cache, but freed).

Signed-off-by Darrick J. Wong <[email protected]>

---

 fs/xfs/xfs_icache.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

fs/xfs/xfs_icache.c +1 -2

index 3422711..43005fb 100644
@@ -610,7 +610,7 @@ xfs_iget(
 	} else {
 		rcu_read_unlock();
 		if (flags & XFS_IGET_INCORE) {
-			error = -ENOENT;
+			error = -ENODATA;
 			goto out_error_or_again;
 		}
 		XFS_STATS_INC(mp, xs_ig_missed);
 
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From: Darrick J. Wong <[email protected]>

Establish an ioctl for userspace to query the original and current per-AG reservation counts. This will be used by xfs_scrub to check that the vfs counters are at least somewhat sane.

Signed-off-by Darrick J. Wong <[email protected]>

---

 fs/xfs/libxfs/xfs_fs.h |   12 ++++++++++++
 fs/xfs/xfs_fsops.c     |   26 ++++++++++++++++++++++++++
 fs/xfs/xfs_fsops.h     |    2 ++
 fs/xfs/xfs_ioctl.c     |   24 ++++++++++++++++++++++++
 fs/xfs/xfs_ioctl32.c   |    1 +
 5 files changed, 65 insertions(+)

fs/xfs/libxfs/xfs_fs.h +12 -0

index 8c61f21..2c26c38 100644
@@ -469,6 +469,17 @@ typedef struct xfs_swapext
 #define XFS_FSOP_GOING_FLAGS_NOLOGFLUSH		0x2	/* don't flush log nor data */
 
 /*
+ * AG reserved block counters
+ */
+struct xfs_fsop_ag_resblks {
+	__u32 ar_flags;			/* output flags, none defined now */
+	__u32 ar_reserved;		/* zero */
+	__u64 ar_current_resv;		/* blocks reserved now */
+	__u64 ar_mount_resv;		/* blocks reserved at mount time */
+	__u64 ar_reserved2[5];		/* zero */
+};
+
+/*
  * ioctl limits
  */
 #ifdef XATTR_LIST_MAX

@@ -543,6 +554,7 @@ typedef struct xfs_swapext
 #define XFS_IOC_ATTRMULTI_BY_HANDLE  _IOW ('X', 123, struct xfs_fsop_attrmulti_handlereq)
 #define XFS_IOC_FSGEOMETRY	     _IOR ('X', 124, struct xfs_fsop_geom)
 #define XFS_IOC_GOINGDOWN	     _IOR ('X', 125, uint32_t)
+#define XFS_IOC_GET_AG_RESBLKS	     _IOR ('X', 126, struct xfs_fsop_ag_resblks)
 /*	XFS_IOC_GETFSUUID ---------- deprecated 140	 */
 
 

fs/xfs/xfs_fsops.c +26 -0

index 8f22fc5..50fb3a2 100644
@@ -44,6 +44,7 @@
 #include "xfs_filestream.h"
 #include "xfs_rmap.h"
 #include "xfs_ag_resv.h"
+#include "xfs_fs.h"
 
 /*
  * File system operations

@@ -1046,3 +1047,28 @@ xfs_fs_unreserve_ag_blocks(
 
 	return error;
 }
+
+/* Query the per-AG reservations to see how many blocks we have reserved. */
+int
+xfs_fs_get_ag_reserve_blocks(
+	struct xfs_mount		*mp,
+	struct xfs_fsop_ag_resblks	*out)
+{
+	struct xfs_ag_resv		*r;
+	struct xfs_perag		*pag;
+	xfs_agnumber_t			agno;
+
+	memset(out, 0, sizeof(struct xfs_fsop_ag_resblks));
+	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
+		pag = xfs_perag_get(mp, agno);
+		r = xfs_perag_resv(pag, XFS_AG_RESV_METADATA);
+		out->ar_current_resv += r->ar_reserved;
+		out->ar_mount_resv += r->ar_asked;
+		r = xfs_perag_resv(pag, XFS_AG_RESV_AGFL);
+		out->ar_current_resv += r->ar_reserved;
+		out->ar_mount_resv += r->ar_asked;
+		xfs_perag_put(pag);
+	}
+
+	return 0;
+}

fs/xfs/xfs_fsops.h +2 -0

index 2954c13..c8f5e26 100644
@@ -25,6 +25,8 @@ extern int xfs_fs_counts(xfs_mount_t *mp, xfs_fsop_counts_t *cnt);
 extern int xfs_reserve_blocks(xfs_mount_t *mp, uint64_t *inval,
 				xfs_fsop_resblks_t *outval);
 extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
+extern int xfs_fs_get_ag_reserve_blocks(struct xfs_mount *mp,
+		struct xfs_fsop_ag_resblks *out);
 
 extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
 extern int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);

fs/xfs/xfs_ioctl.c +24 -0

index 5049e8a..44dc178 100644
@@ -1782,6 +1782,27 @@ xfs_ioc_swapext(
 	return error;
 }
 
+static int
+xfs_ioc_get_ag_reserve_blocks(
+	struct xfs_mount		*mp,
+	void __user			*arg)
+{
+	struct xfs_fsop_ag_resblks	out;
+	int				error;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	error = xfs_fs_get_ag_reserve_blocks(mp, &out);
+	if (error)
+		return error;
+
+	if (copy_to_user(arg, &out, sizeof(out)))
+		return -EFAULT;
+
+	return 0;
+}
+
 /*
  * Note: some of the ioctl's return positive numbers as a
  * byte count indicating success, such as readlink_by_handle.

@@ -1987,6 +2008,9 @@ xfs_file_ioctl(
 		return 0;
 	}
 
+	case XFS_IOC_GET_AG_RESBLKS:
+		return xfs_ioc_get_ag_reserve_blocks(mp, arg);
+
 	case XFS_IOC_FSGROWFSDATA: {
 		xfs_growfs_data_t in;
 

fs/xfs/xfs_ioctl32.c +1 -1

index fa0bc4d..e8b4de3 100644
@@ -556,6 +556,7 @@ xfs_file_compat_ioctl(
 	case XFS_IOC_ERROR_INJECTION:
 	case XFS_IOC_ERROR_CLEARALL:
 	case FS_IOC_GETFSMAP:
+	case XFS_IOC_GET_AG_RESBLKS:
 		return xfs_file_ioctl(filp, cmd, p);
 #ifndef BROKEN_X86_ALIGNMENT
 	/* These are handled fine if no alignment issues */
 
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Quoted 6 lines · Darrick J. Wong

From: Darrick J. Wong <[email protected]>

Establish an ioctl for userspace to query the original and current per-AG reservation counts. This will be used by xfs_scrub to check that the vfs counters are at least somewhat sane.

Quoted 2 lines

Signed-off-by Darrick J. Wong <[email protected]>

---

The code seems fine, but I'm wondering how much of this would remain as is based on Dave's potential switch of the perag res stuff to be a hidden reservation. That itself still needs to be posted/reviewed/etc., so might it be smarter to defer defining an interface to export this stuff until the core mechanism is worked out?

That aside, I'm also wondering how/what userspace scrub does with the overall total values as opposed to individual AG reservation values.

Are the current "ask" values expected to be uniform across each AG..?

For example, what happens if one AG has a bogus "current" value for whatever reason (perhaps this is more relevant for both values if we do actually end up with on-disk reservations)?

Brian

Quoted 148 lines

 fs/xfs/libxfs/xfs_fs.h |   12 ++++++++++++
 fs/xfs/xfs_fsops.c     |   26 ++++++++++++++++++++++++++
 fs/xfs/xfs_fsops.h     |    2 ++
 fs/xfs/xfs_ioctl.c     |   24 ++++++++++++++++++++++++
 fs/xfs/xfs_ioctl32.c   |    1 +
 5 files changed, 65 insertions(+)

fs/xfs/libxfs/xfs_fs.h +12 -0

index 8c61f21..2c26c38 100644
@@ -469,6 +469,17 @@ typedef struct xfs_swapext
 #define XFS_FSOP_GOING_FLAGS_NOLOGFLUSH		0x2	/* don't flush log nor data */
 
 /*
+ * AG reserved block counters
+ */
+struct xfs_fsop_ag_resblks {
+	__u32 ar_flags;			/* output flags, none defined now */
+	__u32 ar_reserved;		/* zero */
+	__u64 ar_current_resv;		/* blocks reserved now */
+	__u64 ar_mount_resv;		/* blocks reserved at mount time */
+	__u64 ar_reserved2[5];		/* zero */
+};
+
+/*
  * ioctl limits
  */
 #ifdef XATTR_LIST_MAX

@@ -543,6 +554,7 @@ typedef struct xfs_swapext
 #define XFS_IOC_ATTRMULTI_BY_HANDLE  _IOW ('X', 123, struct xfs_fsop_attrmulti_handlereq)
 #define XFS_IOC_FSGEOMETRY	     _IOR ('X', 124, struct xfs_fsop_geom)
 #define XFS_IOC_GOINGDOWN	     _IOR ('X', 125, uint32_t)
+#define XFS_IOC_GET_AG_RESBLKS	     _IOR ('X', 126, struct xfs_fsop_ag_resblks)
 /*	XFS_IOC_GETFSUUID ---------- deprecated 140	 */
 
 

fs/xfs/xfs_fsops.c +26 -0

index 8f22fc5..50fb3a2 100644
@@ -44,6 +44,7 @@
 #include "xfs_filestream.h"
 #include "xfs_rmap.h"
 #include "xfs_ag_resv.h"
+#include "xfs_fs.h"
 
 /*
  * File system operations

@@ -1046,3 +1047,28 @@ xfs_fs_unreserve_ag_blocks(
 
 	return error;
 }
+
+/* Query the per-AG reservations to see how many blocks we have reserved. */
+int
+xfs_fs_get_ag_reserve_blocks(
+	struct xfs_mount		*mp,
+	struct xfs_fsop_ag_resblks	*out)
+{
+	struct xfs_ag_resv		*r;
+	struct xfs_perag		*pag;
+	xfs_agnumber_t			agno;
+
+	memset(out, 0, sizeof(struct xfs_fsop_ag_resblks));
+	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
+		pag = xfs_perag_get(mp, agno);
+		r = xfs_perag_resv(pag, XFS_AG_RESV_METADATA);
+		out->ar_current_resv += r->ar_reserved;
+		out->ar_mount_resv += r->ar_asked;
+		r = xfs_perag_resv(pag, XFS_AG_RESV_AGFL);
+		out->ar_current_resv += r->ar_reserved;
+		out->ar_mount_resv += r->ar_asked;
+		xfs_perag_put(pag);
+	}
+
+	return 0;
+}

fs/xfs/xfs_fsops.h +2 -0

index 2954c13..c8f5e26 100644
@@ -25,6 +25,8 @@ extern int xfs_fs_counts(xfs_mount_t *mp, xfs_fsop_counts_t *cnt);
 extern int xfs_reserve_blocks(xfs_mount_t *mp, uint64_t *inval,
 				xfs_fsop_resblks_t *outval);
 extern int xfs_fs_goingdown(xfs_mount_t *mp, uint32_t inflags);
+extern int xfs_fs_get_ag_reserve_blocks(struct xfs_mount *mp,
+		struct xfs_fsop_ag_resblks *out);
 
 extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
 extern int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);

fs/xfs/xfs_ioctl.c +24 -0

index 5049e8a..44dc178 100644
@@ -1782,6 +1782,27 @@ xfs_ioc_swapext(
 	return error;
 }
 
+static int
+xfs_ioc_get_ag_reserve_blocks(
+	struct xfs_mount		*mp,
+	void __user			*arg)
+{
+	struct xfs_fsop_ag_resblks	out;
+	int				error;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	error = xfs_fs_get_ag_reserve_blocks(mp, &out);
+	if (error)
+		return error;
+
+	if (copy_to_user(arg, &out, sizeof(out)))
+		return -EFAULT;
+
+	return 0;
+}
+
 /*
  * Note: some of the ioctl's return positive numbers as a
  * byte count indicating success, such as readlink_by_handle.

@@ -1987,6 +2008,9 @@ xfs_file_ioctl(
 		return 0;
 	}
 
+	case XFS_IOC_GET_AG_RESBLKS:
+		return xfs_ioc_get_ag_reserve_blocks(mp, arg);
+
 	case XFS_IOC_FSGROWFSDATA: {
 		xfs_growfs_data_t in;
 

fs/xfs/xfs_ioctl32.c +1 -1

index fa0bc4d..e8b4de3 100644
@@ -556,6 +556,7 @@ xfs_file_compat_ioctl(
 	case XFS_IOC_ERROR_INJECTION:
 	case XFS_IOC_ERROR_CLEARALL:
 	case FS_IOC_GETFSMAP:
+	case XFS_IOC_GET_AG_RESBLKS:
 		return xfs_file_ioctl(filp, cmd, p);
 #ifndef BROKEN_X86_ALIGNMENT
 	/* These are handled fine if no alignment issues */
 
--

Quoted 3 lines

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From: Darrick J. Wong <[email protected]>

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 <[email protected]>

---
 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

fs/xfs/Kconfig +17 -0

index 1b98cfa..f42fcf1 100644
@@ -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

fs/xfs/Makefile +11 -0

index dbc33e0..f4312bc 100644
@@ -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

fs/xfs/libxfs/xfs_fs.h +53 -0

index 2c26c38..a4b4c8c 100644
@@ -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

fs/xfs/scrub/scrub.c new file +54 -0

new file mode 100644
index 0000000..5db2a6f
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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;
+}

fs/xfs/scrub/scrub.h new file +25 -0

new file mode 100644
index 0000000..eb1cd9d
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/scrub/trace.c new file +41 -0

new file mode 100644
index 0000000..c59fd41
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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"

fs/xfs/scrub/trace.h new file +33 -0

new file mode 100644
index 0000000..a95a7c8
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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>

fs/xfs/scrub/xfs_scrub.h new file +29 -0

new file mode 100644
index 0000000..e00e0ea
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/xfs_ioctl.c +28 -0

index 44dc178..ab7a7f8 100644
@@ -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: {

fs/xfs/xfs_ioctl32.c +1 -1

index e8b4de3..972d4bd 100644
@@ -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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Quoted 17 lines · Darrick J. Wong

From: Darrick J. Wong <[email protected]>

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 <[email protected]>

---
 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 +++++++++++++++++++++++++

Quoted 10 lines

 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

Quoted 397 lines

fs/xfs/Kconfig +17 -0

index 1b98cfa..f42fcf1 100644
@@ -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

fs/xfs/Makefile +11 -0

index dbc33e0..f4312bc 100644
@@ -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

fs/xfs/libxfs/xfs_fs.h +53 -0

index 2c26c38..a4b4c8c 100644
@@ -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

fs/xfs/scrub/scrub.c new file +54 -0

new file mode 100644
index 0000000..5db2a6f
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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;
+}

fs/xfs/scrub/scrub.h new file +25 -0

new file mode 100644
index 0000000..eb1cd9d
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/scrub/trace.c new file +41 -0

new file mode 100644
index 0000000..c59fd41
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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"

fs/xfs/scrub/trace.h new file +33 -0

new file mode 100644
index 0000000..a95a7c8
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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>

fs/xfs/scrub/xfs_scrub.h new file +29 -0

new file mode 100644
index 0000000..e00e0ea
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/xfs_ioctl.c +28 -0

index 44dc178..ab7a7f8 100644
@@ -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: {

fs/xfs/xfs_ioctl32.c +1 -1

index e8b4de3..972d4bd 100644
@@ -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 */
 
--

Quoted 3 lines

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Quoted 29 lines · Brian Foster

Quoted 27 lines · Darrick J. Wong

From: Darrick J. Wong <[email protected]>

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 <[email protected]>

---
 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

Quoted 2 lines

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..

Yes, the ioctl needs documentation, though I'm unclear on where's an appropriate place to put them. The ioctl is not intended for general consumption, so man-pages.git seems inappropriate. I was thinking either in xfs_fs.h directly, or perhaps xfsprogs' man pages?

(We don't seem to document the xfs ioctls afaict?)

--D

Quoted 399 lines

Brian

Quoted 396 lines

fs/xfs/Kconfig +17 -0

index 1b98cfa..f42fcf1 100644
@@ -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

fs/xfs/Makefile +11 -0

index dbc33e0..f4312bc 100644
@@ -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

fs/xfs/libxfs/xfs_fs.h +53 -0

index 2c26c38..a4b4c8c 100644
@@ -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

fs/xfs/scrub/scrub.c new file +54 -0

new file mode 100644
index 0000000..5db2a6f
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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;
+}

fs/xfs/scrub/scrub.h new file +25 -0

new file mode 100644
index 0000000..eb1cd9d
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/scrub/trace.c new file +41 -0

new file mode 100644
index 0000000..c59fd41
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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"

fs/xfs/scrub/trace.h new file +33 -0

new file mode 100644
index 0000000..a95a7c8
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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>

fs/xfs/scrub/xfs_scrub.h new file +29 -0

new file mode 100644
index 0000000..e00e0ea
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/xfs_ioctl.c +28 -0

index 44dc178..ab7a7f8 100644
@@ -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: {

fs/xfs/xfs_ioctl32.c +1 -0

index e8b4de3..972d4bd 100644
@@ -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 */

Quoted 8 lines

Quoted 4 lines

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Quoted 30 lines · Darrick J. Wong

Quoted 29 lines · Brian Foster

Quoted 27 lines · Darrick J. Wong

From: Darrick J. Wong <[email protected]>

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 <[email protected]>

---
 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

Quoted 8 lines

Quoted 2 lines

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..

Yes, the ioctl needs documentation, though I'm unclear on where's an appropriate place to put them. The ioctl is not intended for general consumption, so man-pages.git seems inappropriate. I was thinking either in xfs_fs.h directly, or perhaps xfsprogs' man pages?

For now (while all of this is still experimental and until you get a better answer :P), it seems reasonable enough to me to add basic interface documentation to the kernel source. Then we at least have the content and can move it out into a manpage or something later, if needed.

Brian

Quoted 411 lines

(We don't seem to document the xfs ioctls afaict?)

--D

Quoted 399 lines

Brian

Quoted 396 lines

fs/xfs/Kconfig +17 -0

index 1b98cfa..f42fcf1 100644
@@ -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

fs/xfs/Makefile +11 -0

index dbc33e0..f4312bc 100644
@@ -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

fs/xfs/libxfs/xfs_fs.h +53 -0

index 2c26c38..a4b4c8c 100644
@@ -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

fs/xfs/scrub/scrub.c new file +54 -0

new file mode 100644
index 0000000..5db2a6f
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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;
+}

fs/xfs/scrub/scrub.h new file +25 -0

new file mode 100644
index 0000000..eb1cd9d
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/scrub/trace.c new file +41 -0

new file mode 100644
index 0000000..c59fd41
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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"

fs/xfs/scrub/trace.h new file +33 -0

new file mode 100644
index 0000000..a95a7c8
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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>

fs/xfs/scrub/xfs_scrub.h new file +29 -0

new file mode 100644
index 0000000..e00e0ea
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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__ */

fs/xfs/xfs_ioctl.c +28 -0

index 44dc178..ab7a7f8 100644
@@ -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: {

fs/xfs/xfs_ioctl32.c +1 -0

index e8b4de3..972d4bd 100644
@@ -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 */

Quoted 8 lines

Quoted 4 lines

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Quoted 4 lines

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From: Darrick J. Wong <[email protected]>

Create structures needed to hold scrubbing context and dispatch incoming commands to the individual scrubbers.

Signed-off-by Darrick J. Wong <[email protected]>

---
 fs/xfs/scrub/scrub.c |  172 ++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/scrub.h |   19 ++++++
 fs/xfs/scrub/trace.h |   43 +++++++++++++
 3 files changed, 233 insertions(+), 1 deletion(-)

fs/xfs/scrub/scrub.c +52 -0

index 5db2a6f..7cf518e 100644
@@ -44,11 +44,181 @@
 #include "scrub/scrub.h"
 #include "scrub/trace.h"
 
+/*
+ * Online Scrub and Repair
+ *
+ * Traditionally, XFS (the kernel driver) did not know how to check or
+ * repair on-disk data structures.  That task was left to the xfs_check
+ * and xfs_repair tools, both of which require taking the filesystem
+ * offline for a thorough but time consuming examination.  Online
+ * scrub & repair, on the other hand, enables us to check the metadata
+ * for obvious errors while carefully stepping around the filesystem's
+ * ongoing operations, locking rules, etc.
+ *
+ * Given that most XFS metadata consist of records stored in a btree,
+ * most of the checking functions iterate the btree blocks themselves
+ * looking for irregularities.  When a record block is encountered, each
+ * record can be checked for obviously bad values.  Record values can
+ * also be cross-referenced against other btrees to look for potential
+ * misunderstandings between pieces of metadata.
+ *
+ * It is expected that the checkers responsible for per-AG metadata
+ * structures will lock the AG headers (AGI, AGF, AGFL), iterate the
+ * metadata structure, and perform any relevant cross-referencing before
+ * unlocking the AG and returning the results to userspace.  These
+ * scrubbers must not keep an AG locked for too long to avoid tying up
+ * the block and inode allocators.
+ *
+ * Block maps and b-trees rooted in an inode present a special challenge
+ * because they can involve extents from any AG.  The general scrubber
+ * structure of lock -> check -> xref -> unlock still holds, but AG
+ * locking order rules /must/ be obeyed to avoid deadlocks.  The
+ * ordering rule, of course, is that we must lock in increasing AG
+ * order.  Helper functions are provided to track which AG headers we've
+ * already locked.  If we detect an imminent locking order violation, we
+ * can signal a potential deadlock, in which case the scrubber can jump
+ * out to the top level, lock all the AGs in order, and retry the scrub.
+ *
+ * For file data (directories, extended attributes, symlinks) scrub, we
+ * can simply lock the inode and walk the data.  For btree data
+ * (directories and attributes) we follow the same btree-scrubbing
+ * strategy outlined previously to check the records.
+ *
+ * We use a bit of trickery with transactions to avoid buffer deadlocks
+ * if there is a cycle in the metadata.  The basic problem is that
+ * travelling down a btree involves locking the current buffer at each
+ * tree level.  If a pointer should somehow point back to a buffer that
+ * we've already examined, we will deadlock due to the second buffer
+ * locking attempt.  Note however that grabbing a buffer in transaction
+ * context links the locked buffer to the transaction.  If we try to
+ * re-grab the buffer in the context of the same transaction, we avoid
+ * the second lock attempt and continue.  Between the verifier and the
+ * scrubber, something will notice that something is amiss and report
+ * the corruption.  Therefore, each scrubber will allocate an empty
+ * transaction, attach buffers to it, and cancel the transaction at the

fs/xfs/scrub/scrub.c +100 -1

+{
+	if (sc->tp) {
+		xfs_trans_cancel(sc->tp);
+		sc->tp = NULL;
+	}
+	return error;
+}
+
+/* Scrubbing dispatch. */
+
+static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
+};
+
 /* Dispatch metadata scrubbing. */
 int
 xfs_scrub_metadata(
 	struct xfs_inode		*ip,
 	struct xfs_scrub_metadata	*sm)
 {
-	return -EOPNOTSUPP;
+	struct xfs_scrub_context	sc;
+	struct xfs_mount		*mp = ip->i_mount;
+	const struct xfs_scrub_meta_ops	*ops;
+	bool				try_harder = false;
+	int				error = 0;
+
+	trace_xfs_scrub_start(ip, sm, error);
+
+	/* Forbidden if we are shut down or mounted norecovery. */
+	error = -ESHUTDOWN;
+	if (XFS_FORCED_SHUTDOWN(mp))
+		goto out;
+	error = -ENOTRECOVERABLE;
+	if (mp->m_flags & XFS_MOUNT_NORECOVERY)
+		goto out;
+
+	/* Check our inputs. */
+	error = -EINVAL;
+	sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
+	if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN)
+		goto out;
+	if (memchr_inv(sm->sm_reserved, 0, sizeof(sm->sm_reserved)))
+		goto out;
+
+	/* Do we know about this type of metadata? */
+	error = -ENOENT;
+	if (sm->sm_type >= XFS_SCRUB_TYPE_NR)
+		goto out;
+	ops = &meta_scrub_ops[sm->sm_type];
+	if (ops->scrub == NULL)
+		goto out;
+
+	/* Does this fs even support this type of metadata? */
+	if (ops->has && !ops->has(&mp->m_sb))
+		goto out;
+
+	/* We don't know how to repair anything yet. */
+	error = -EOPNOTSUPP;
+	if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
+		goto out;
+
+	/* This isn't a stable feature.  Use with care. */
+	{
+		static bool warned;
+
+		if (!warned)
+			xfs_alert(mp,
+	"EXPERIMENTAL online scrub feature in use. Use at your own risk!");
+		warned = true;
+	}
+
+retry_op:
+	/* Set up for the operation. */
+	memset(&sc, 0, sizeof(sc));
+	sc.mp = ip->i_mount;
+	sc.sm = sm;
+	sc.ops = ops;
+	sc.try_harder = try_harder;
+	error = sc.ops->setup(&sc, ip);
+	if (error)
+		goto out_teardown;
+
+	/* Scrub for errors. */
+	error = sc.ops->scrub(&sc);
+	if (!try_harder && error == -EDEADLOCK) {
+		/*
+		 * Scrubbers return -EDEADLOCK to mean 'try harder'.
+		 * Tear down everything we hold, then set up again with
+		 * preparation for worst-case scenarios.
+		 */
+		error = xfs_scrub_teardown(&sc, 0);
+		if (error)
+			goto out;
+		try_harder = true;
+		goto retry_op;
+	} else if (error)
+		goto out_teardown;
+
+	if (sc.sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
+			       XFS_SCRUB_OFLAG_XCORRUPT))
+		xfs_alert_ratelimited(mp, "Corruption detected during scrub.");
+
+out_teardown:
+	error = xfs_scrub_teardown(&sc, error);
+out:
+	trace_xfs_scrub_done(ip, sm, error);
+	return error;
 }

fs/xfs/scrub/scrub.h +0 -0

index eb1cd9d..b271b2a 100644

fs/xfs/scrub/scrub.h +12 -0

+};
+
+struct xfs_scrub_context {
+	/* General scrub state. */
+	struct xfs_mount		*mp;
+	struct xfs_scrub_metadata	*sm;
+	const struct xfs_scrub_meta_ops	*ops;
+	struct xfs_trans		*tp;
+	struct xfs_inode		*ip;
+	bool				try_harder;
+};
+
 /* Metadata scrubbers */
 
 #endif	/* __XFS_SCRUB_SCRUB_H__ */

fs/xfs/scrub/trace.h +43 -1

index a95a7c8..688517e 100644
@@ -25,6 +25,49 @@
 
 #include <linux/tracepoint.h>
 
+DECLARE_EVENT_CLASS(xfs_scrub_class,
+	TP_PROTO(struct xfs_inode *ip, struct xfs_scrub_metadata *sm,
+		 int error),
+	TP_ARGS(ip, sm, error),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_ino_t, ino)
+		__field(unsigned int, type)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_ino_t, inum)
+		__field(unsigned int, gen)
+		__field(unsigned int, flags)
+		__field(int, error)
+	),
+	TP_fast_assign(
+		__entry->dev = ip->i_mount->m_super->s_dev;
+		__entry->ino = ip->i_ino;
+		__entry->type = sm->sm_type;
+		__entry->agno = sm->sm_agno;
+		__entry->inum = sm->sm_ino;
+		__entry->gen = sm->sm_gen;
+		__entry->flags = sm->sm_flags;
+		__entry->error = error;
+	),
+	TP_printk("dev %d:%d ino %llu type %u agno %u inum %llu gen %u flags 0x%x error %d",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino,
+		  __entry->type,
+		  __entry->agno,
+		  __entry->inum,
+		  __entry->gen,
+		  __entry->flags,
+		  __entry->error)
+)
+#define DEFINE_SCRUB_EVENT(name) \
+DEFINE_EVENT(xfs_scrub_class, name, \
+	TP_PROTO(struct xfs_inode *ip, struct xfs_scrub_metadata *sm, \
+		 int error), \
+	TP_ARGS(ip, sm, error))
+
+DEFINE_SCRUB_EVENT(xfs_scrub_start);
+DEFINE_SCRUB_EVENT(xfs_scrub_done);
+
 #endif /* _TRACE_XFS_SCRUB_TRACE_H */
 
 #undef TRACE_INCLUDE_PATH
 
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Quoted 77 lines · Darrick J. Wong

From: Darrick J. Wong <[email protected]>

Create structures needed to hold scrubbing context and dispatch incoming commands to the individual scrubbers.

Signed-off-by Darrick J. Wong <[email protected]>

---
 fs/xfs/scrub/scrub.c |  172 ++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/scrub.h |   19 ++++++
 fs/xfs/scrub/trace.h |   43 +++++++++++++
 3 files changed, 233 insertions(+), 1 deletion(-)

fs/xfs/scrub/scrub.c +56 -0

index 5db2a6f..7cf518e 100644
@@ -44,11 +44,181 @@
 #include "scrub/scrub.h"
 #include "scrub/trace.h"
 
+/*
+ * Online Scrub and Repair
+ *
+ * Traditionally, XFS (the kernel driver) did not know how to check or
+ * repair on-disk data structures.  That task was left to the xfs_check
+ * and xfs_repair tools, both of which require taking the filesystem
+ * offline for a thorough but time consuming examination.  Online
+ * scrub & repair, on the other hand, enables us to check the metadata
+ * for obvious errors while carefully stepping around the filesystem's
+ * ongoing operations, locking rules, etc.
+ *
+ * Given that most XFS metadata consist of records stored in a btree,
+ * most of the checking functions iterate the btree blocks themselves
+ * looking for irregularities.  When a record block is encountered, each
+ * record can be checked for obviously bad values.  Record values can
+ * also be cross-referenced against other btrees to look for potential
+ * misunderstandings between pieces of metadata.
+ *
+ * It is expected that the checkers responsible for per-AG metadata
+ * structures will lock the AG headers (AGI, AGF, AGFL), iterate the
+ * metadata structure, and perform any relevant cross-referencing before
+ * unlocking the AG and returning the results to userspace.  These
+ * scrubbers must not keep an AG locked for too long to avoid tying up
+ * the block and inode allocators.
+ *
+ * Block maps and b-trees rooted in an inode present a special challenge
+ * because they can involve extents from any AG.  The general scrubber
+ * structure of lock -> check -> xref -> unlock still holds, but AG
+ * locking order rules /must/ be obeyed to avoid deadlocks.  The
+ * ordering rule, of course, is that we must lock in increasing AG
+ * order.  Helper functions are provided to track which AG headers we've
+ * already locked.  If we detect an imminent locking order violation, we
+ * can signal a potential deadlock, in which case the scrubber can jump
+ * out to the top level, lock all the AGs in order, and retry the scrub.
+ *
+ * For file data (directories, extended attributes, symlinks) scrub, we
+ * can simply lock the inode and walk the data.  For btree data
+ * (directories and attributes) we follow the same btree-scrubbing
+ * strategy outlined previously to check the records.
+ *
+ * We use a bit of trickery with transactions to avoid buffer deadlocks
+ * if there is a cycle in the metadata.  The basic problem is that
+ * travelling down a btree involves locking the current buffer at each
+ * tree level.  If a pointer should somehow point back to a buffer that
+ * we've already examined, we will deadlock due to the second buffer
+ * locking attempt.  Note however that grabbing a buffer in transaction
+ * context links the locked buffer to the transaction.  If we try to
+ * re-grab the buffer in the context of the same transaction, we avoid
+ * the second lock attempt and continue.  Between the verifier and the
+ * scrubber, something will notice that something is amiss and report
+ * the corruption.  Therefore, each scrubber will allocate an empty
+ * transaction, attach buffers to it, and cancel the transaction at the
+ * end of the scrub run.  Cancelling a non-dirty transaction simply
+ * unlocks the buffers.
+ *
+ * There are four pieces of data that scrub can communicate to

fs/xfs/scrub/scrub.c line 108

Quoted 6 lines

fs/xfs/scrub/scrub.c +6 -0

+ * userspace.  The first is the error code (errno), which can be used to
+ * communicate operational errors in performing the scrub.  There are
+ * also three flags that can be set in the scrub context.  If the data
+ * structure itself is corrupt, the CORRUPT flag will be set.  If
+ * the metadata is correct but otherwise suboptimal, the PREEN flag
+ * will be set.

Did you mean to describe other flags here?

fs/xfs/scrub/scrub.c line 117

Quoted 9 lines

fs/xfs/scrub/scrub.c +9 -0

+ */
+
+/* Scrub setup and teardown */
+
+/* Free all the resources and finish the transactions. */
+STATIC int
+xfs_scrub_teardown(
+	struct xfs_scrub_context	*sc,
+	int				error)

What's the purpose of passing error just to return it?

Quoted 116 lines

fs/xfs/scrub/scrub.c +100 -1

+{
+	if (sc->tp) {
+		xfs_trans_cancel(sc->tp);
+		sc->tp = NULL;
+	}
+	return error;
+}
+
+/* Scrubbing dispatch. */
+
+static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
+};
+
 /* Dispatch metadata scrubbing. */
 int
 xfs_scrub_metadata(
 	struct xfs_inode		*ip,
 	struct xfs_scrub_metadata	*sm)
 {
-	return -EOPNOTSUPP;
+	struct xfs_scrub_context	sc;
+	struct xfs_mount		*mp = ip->i_mount;
+	const struct xfs_scrub_meta_ops	*ops;
+	bool				try_harder = false;
+	int				error = 0;
+
+	trace_xfs_scrub_start(ip, sm, error);
+
+	/* Forbidden if we are shut down or mounted norecovery. */
+	error = -ESHUTDOWN;
+	if (XFS_FORCED_SHUTDOWN(mp))
+		goto out;
+	error = -ENOTRECOVERABLE;
+	if (mp->m_flags & XFS_MOUNT_NORECOVERY)
+		goto out;
+
+	/* Check our inputs. */
+	error = -EINVAL;
+	sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
+	if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN)
+		goto out;
+	if (memchr_inv(sm->sm_reserved, 0, sizeof(sm->sm_reserved)))
+		goto out;
+
+	/* Do we know about this type of metadata? */
+	error = -ENOENT;
+	if (sm->sm_type >= XFS_SCRUB_TYPE_NR)
+		goto out;
+	ops = &meta_scrub_ops[sm->sm_type];
+	if (ops->scrub == NULL)
+		goto out;
+
+	/* Does this fs even support this type of metadata? */
+	if (ops->has && !ops->has(&mp->m_sb))
+		goto out;
+
+	/* We don't know how to repair anything yet. */
+	error = -EOPNOTSUPP;
+	if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
+		goto out;
+
+	/* This isn't a stable feature.  Use with care. */
+	{
+		static bool warned;
+
+		if (!warned)
+			xfs_alert(mp,
+	"EXPERIMENTAL online scrub feature in use. Use at your own risk!");
+		warned = true;
+	}
+
+retry_op:
+	/* Set up for the operation. */
+	memset(&sc, 0, sizeof(sc));
+	sc.mp = ip->i_mount;
+	sc.sm = sm;
+	sc.ops = ops;
+	sc.try_harder = try_harder;
+	error = sc.ops->setup(&sc, ip);
+	if (error)
+		goto out_teardown;
+
+	/* Scrub for errors. */
+	error = sc.ops->scrub(&sc);
+	if (!try_harder && error == -EDEADLOCK) {
+		/*
+		 * Scrubbers return -EDEADLOCK to mean 'try harder'.
+		 * Tear down everything we hold, then set up again with
+		 * preparation for worst-case scenarios.
+		 */
+		error = xfs_scrub_teardown(&sc, 0);
+		if (error)
+			goto out;
+		try_harder = true;
+		goto retry_op;
+	} else if (error)
+		goto out_teardown;
+
+	if (sc.sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
+			       XFS_SCRUB_OFLAG_XCORRUPT))
+		xfs_alert_ratelimited(mp, "Corruption detected during scrub.");
+
+out_teardown:
+	error = xfs_scrub_teardown(&sc, error);
+out:
+	trace_xfs_scrub_done(ip, sm, error);
+	return error;
 }

fs/xfs/scrub/scrub.h +0 -0

index eb1cd9d..b271b2a 100644
@@ -20,6 +20,25 @@
 #ifndef __XFS_SCRUB_SCRUB_H__
 #define __XFS_SCRUB_SCRUB_H__
 

fs/xfs/scrub/scrub.h line 29

Quoted 7 lines

fs/xfs/scrub/scrub.h +7 -0

+struct xfs_scrub_context;
+
+struct xfs_scrub_meta_ops {
+	int		(*setup)(struct xfs_scrub_context *,
+				 struct xfs_inode *);
+	int		(*scrub)(struct xfs_scrub_context *);
+	bool		(*has)(struct xfs_sb *);

I assume 'has' is to identify whether a particular mount supports a particular feature. I suppose a better name would be nice here, or perhaps just a comment to outline the purpose of each callout.

Brian

Quoted 71 lines

fs/xfs/scrub/scrub.h +12 -0

+};
+
+struct xfs_scrub_context {
+	/* General scrub state. */
+	struct xfs_mount		*mp;
+	struct xfs_scrub_metadata	*sm;
+	const struct xfs_scrub_meta_ops	*ops;
+	struct xfs_trans		*tp;
+	struct xfs_inode		*ip;
+	bool				try_harder;
+};
+
 /* Metadata scrubbers */
 
 #endif	/* __XFS_SCRUB_SCRUB_H__ */

fs/xfs/scrub/trace.h +43 -1

index a95a7c8..688517e 100644
@@ -25,6 +25,49 @@
 
 #include <linux/tracepoint.h>
 
+DECLARE_EVENT_CLASS(xfs_scrub_class,
+	TP_PROTO(struct xfs_inode *ip, struct xfs_scrub_metadata *sm,
+		 int error),
+	TP_ARGS(ip, sm, error),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_ino_t, ino)
+		__field(unsigned int, type)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_ino_t, inum)
+		__field(unsigned int, gen)
+		__field(unsigned int, flags)
+		__field(int, error)
+	),
+	TP_fast_assign(
+		__entry->dev = ip->i_mount->m_super->s_dev;
+		__entry->ino = ip->i_ino;
+		__entry->type = sm->sm_type;
+		__entry->agno = sm->sm_agno;
+		__entry->inum = sm->sm_ino;
+		__entry->gen = sm->sm_gen;
+		__entry->flags = sm->sm_flags;
+		__entry->error = error;
+	),
+	TP_printk("dev %d:%d ino %llu type %u agno %u inum %llu gen %u flags 0x%x error %d",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino,
+		  __entry->type,
+		  __entry->agno,
+		  __entry->inum,
+		  __entry->gen,
+		  __entry->flags,
+		  __entry->error)
+)
+#define DEFINE_SCRUB_EVENT(name) \
+DEFINE_EVENT(xfs_scrub_class, name, \
+	TP_PROTO(struct xfs_inode *ip, struct xfs_scrub_metadata *sm, \
+		 int error), \
+	TP_ARGS(ip, sm, error))
+
+DEFINE_SCRUB_EVENT(xfs_scrub_start);
+DEFINE_SCRUB_EVENT(xfs_scrub_done);
+
 #endif /* _TRACE_XFS_SCRUB_TRACE_H */
 
 #undef TRACE_INCLUDE_PATH
 
--

Quoted 3 lines

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From: Darrick J. Wong <[email protected]>

Create a test scrubber with id 0. This will be used by xfs_scrub to probe the kernel's abilities to scrub (and repair) the metadata.

Signed-off-by Darrick J. Wong <[email protected]>

---
 fs/xfs/Makefile        |    1 +
 fs/xfs/libxfs/xfs_fs.h |    3 ++
 fs/xfs/scrub/common.c  |   60 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/common.h  |   44 +++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/scrub.c   |   33 ++++++++++++++++++++++++++
 fs/xfs/scrub/scrub.h   |    1 +
 fs/xfs/scrub/trace.c   |    1 +
 7 files changed, 142 insertions(+), 1 deletion(-)
 create mode 100644 fs/xfs/scrub/common.c
 create mode 100644 fs/xfs/scrub/common.h

fs/xfs/Makefile +1 -0

index f4312bc..ca14595 100644
@@ -146,6 +146,7 @@ ifeq ($(CONFIG_XFS_ONLINE_SCRUB),y)
 
 xfs-y				+= $(addprefix scrub/, \
 				   trace.o \
+				   common.o \
 				   scrub.o \
 				   )
 endif

fs/xfs/libxfs/xfs_fs.h +0 -0

index a4b4c8c..5105bad 100644

fs/xfs/libxfs/xfs_fs.h +1 -1

 /* 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)

fs/xfs/scrub/common.c new file +50 -0

new file mode 100644
index 0000000..13ccb36
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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 */

+/*
+ * Test scrubber -- userspace uses this to probe if we're willing to
+ * scrub or repair a given mountpoint.
+ */

fs/xfs/scrub/common.c new file +10 -0

+int
+xfs_scrub_tester(
+	struct xfs_scrub_context	*sc)
+{
+	if (sc->sm->sm_ino || sc->sm->sm_agno)
+		return -EINVAL;
+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_CORRUPT)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_PREEN)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN;

Quoted 38 lines · Darrick J. Wong

From: Darrick J. Wong <[email protected]>

Create a test scrubber with id 0. This will be used by xfs_scrub to probe the kernel's abilities to scrub (and repair) the metadata.

Signed-off-by Darrick J. Wong <[email protected]>

---
 fs/xfs/Makefile        |    1 +
 fs/xfs/libxfs/xfs_fs.h |    3 ++
 fs/xfs/scrub/common.c  |   60 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/common.h  |   44 +++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/scrub.c   |   33 ++++++++++++++++++++++++++
 fs/xfs/scrub/scrub.h   |    1 +
 fs/xfs/scrub/trace.c   |    1 +
 7 files changed, 142 insertions(+), 1 deletion(-)
 create mode 100644 fs/xfs/scrub/common.c
 create mode 100644 fs/xfs/scrub/common.h

fs/xfs/Makefile +1 -0

index f4312bc..ca14595 100644
@@ -146,6 +146,7 @@ ifeq ($(CONFIG_XFS_ONLINE_SCRUB),y)
 
 xfs-y				+= $(addprefix scrub/, \
 				   trace.o \
+				   common.o \
 				   scrub.o \
 				   )
 endif

fs/xfs/libxfs/xfs_fs.h +0 -0

index a4b4c8c..5105bad 100644
@@ -483,9 +483,10 @@ struct xfs_scrub_metadata {
  */
 

fs/xfs/libxfs/xfs_fs.h struct xfs_scrub_metadata { · line 486

Quoted 2 lines

fs/xfs/libxfs/xfs_fs.h +1 -0

 /* Scrub subcommands. */
+#define XFS_SCRUB_TYPE_TEST	0	/* presence test ioctl */

Shouldn't we call this a "probe" - as in "probe for support" so it doesn't get confused with "use this to test whether scrub works"

Quoted 68 lines

fs/xfs/libxfs/xfs_fs.h +1 -1

 /* 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)

fs/xfs/scrub/common.c new file +55 -0

new file mode 100644
index 0000000..13ccb36
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <[email protected]>
+ *
+ * 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,

fs/xfs/scrub/common.c line 60

Quoted 5 lines

fs/xfs/scrub/common.c new file +5 -0

+	struct xfs_inode		*ip)
+{
+	return xfs_scrub_trans_alloc(sc->sm, sc->mp,
+			&M_RES(sc->mp)->tr_itruncate, 0, 0, 0, &sc->tp);
+}

Using the truncate transaction reservation really needs explaining here....

.....

Quoted 5 lines

+/*
+ * Test scrubber -- userspace uses this to probe if we're willing to
+ * scrub or repair a given mountpoint.
+ */

Yup, definitely should be called xfs_scrub_probe()....

Quoted 10 lines

fs/xfs/scrub/common.c new file +10 -0

+int
+xfs_scrub_tester(
+	struct xfs_scrub_context	*sc)
+{
+	if (sc->sm->sm_ino || sc->sm->sm_agno)
+		return -EINVAL;
+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_CORRUPT)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_PREEN)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_PREEN;

fs/xfs/scrub/common.c

Quoted 10 lines

fs/xfs/scrub/common.c new file +10 -0

+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_XFAIL)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XFAIL;
+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_XCORRUPT)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XCORRUPT;
+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_INCOMPLETE)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_INCOMPLETE;
+	if (sc->sm->sm_gen & XFS_SCRUB_OFLAG_WARNING)
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_WARNING;
+	if (sc->sm->sm_gen & ~XFS_SCRUB_FLAGS_OUT)
+		return -ENOENT;

Shouldn't this check should be first? If not, comment to explain?

Also, I find that really hard to parse because it's so dense and so much is repeated over and over again (makes my pattern matching brain cells scream). It's copying the exact same flags from sc->sm->sm_gen to sc->sm->sm_flags, so why not somethign like: