xfs: scrub inode block mappings

Scrub an individual inode's block mappings to make sure they make sense.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/Makefile

@@ -145,6 +145,7 @@ xfs-y				+= $(addprefix scrub/, \
 				   trace.o \
 				   agheader.o \
 				   alloc.o \
+				   bmap.o \
 				   btree.o \
 				   common.o \
 				   ialloc.o \

fs/xfs/libxfs/xfs_fs.h

@@ -495,9 +495,12 @@ struct xfs_scrub_metadata {
 #define XFS_SCRUB_TYPE_RMAPBT	9	/* reverse mapping btree */
 #define XFS_SCRUB_TYPE_REFCNTBT	10	/* reference count btree */
 #define XFS_SCRUB_TYPE_INODE	11	/* inode record */
+#define XFS_SCRUB_TYPE_BMBTD	12	/* data fork block mapping */
+#define XFS_SCRUB_TYPE_BMBTA	13	/* attr fork block mapping */
+#define XFS_SCRUB_TYPE_BMBTC	14	/* CoW fork block mapping */
 
 /* Number of scrub subcommands. */
-#define XFS_SCRUB_TYPE_NR	12
+#define XFS_SCRUB_TYPE_NR	15
 
 /* i: Repair this metadata. */
 #define XFS_SCRUB_IFLAG_REPAIR		(1 << 0)

fs/xfs/scrub/bmap.c

@@ -0,0 +1,366 @@
+/*
+ * 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_inode_fork.h"
+#include "xfs_alloc.h"
+#include "xfs_rtalloc.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_rmap.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/btree.h"
+#include "scrub/trace.h"
+
+/* Set us up with an inode's bmap. */
+int
+xfs_scrub_setup_inode_bmap(
+	struct xfs_scrub_context	*sc,
+	struct xfs_inode		*ip)
+{
+	struct xfs_mount		*mp = sc->mp;
+	int				error;
+
+	error = xfs_scrub_get_inode(sc, ip);
+	if (error)
+		goto out;
+
+	sc->ilock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
+	xfs_ilock(sc->ip, sc->ilock_flags);
+
+	/*
+	 * We don't want any ephemeral data fork updates sitting around
+	 * while we inspect block mappings, so wait for directio to finish
+	 * and flush dirty data if we have delalloc reservations.
+	 */
+	if (S_ISREG(VFS_I(sc->ip)->i_mode) &&
+	    sc->sm->sm_type == XFS_SCRUB_TYPE_BMBTD) {
+		inode_dio_wait(VFS_I(sc->ip));
+		error = filemap_write_and_wait(VFS_I(sc->ip)->i_mapping);
+		if (error)
+			goto out;
+	}
+
+	/* Got the inode, lock it and we're ready to go. */
+	error = xfs_scrub_trans_alloc(sc->sm, mp, &sc->tp);
+	if (error)
+		goto out;
+	sc->ilock_flags |= XFS_ILOCK_EXCL;
+	xfs_ilock(sc->ip, XFS_ILOCK_EXCL);
+
+out:
+	/* scrub teardown will unlock and release the inode */
+	return error;
+}
+
+/*
+ * Inode fork block mapping (BMBT) scrubber.
+ * More complex than the others because we have to scrub
+ * all the extents regardless of whether or not the fork
+ * is in btree format.
+ */
+
+struct xfs_scrub_bmap_info {
+	struct xfs_scrub_context	*sc;
+	xfs_fileoff_t			lastoff;
+	bool				is_rt;
+	bool				is_shared;
+	int				whichfork;
+};
+
+/* Scrub a single extent record. */
+STATIC int
+xfs_scrub_bmap_extent(
+	struct xfs_inode		*ip,
+	struct xfs_btree_cur		*cur,
+	struct xfs_scrub_bmap_info	*info,
+	struct xfs_bmbt_irec		*irec)
+{
+	struct xfs_mount		*mp = info->sc->mp;
+	struct xfs_buf			*bp = NULL;
+	int				error = 0;
+
+	if (cur)
+		xfs_btree_get_block(cur, 0, &bp);
+
+	/*
+	 * Check for out-of-order extents.  This record could have come
+	 * from the incore list, for which there is no ordering check.
+	 */
+	if (irec->br_startoff < info->lastoff)
+		xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+
+	/* There should never be a "hole" extent in either extent list. */
+	if (irec->br_startblock == HOLESTARTBLOCK)
+		xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+
+	/*
+	 * Check for delalloc extents.  We never iterate the ones in the
+	 * in-core extent scan, and we should never see these in the bmbt.
+	 */
+	if (isnullstartblock(irec->br_startblock))
+		xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+
+	/* Make sure the extent points to a valid place. */
+	if (irec->br_startblock + irec->br_blockcount <= irec->br_startblock)
+		xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+	if (info->is_rt &&
+	    (!xfs_verify_rtbno(mp, irec->br_startblock) ||
+	     !xfs_verify_rtbno(mp, irec->br_startblock +
+				irec->br_blockcount - 1)))
+		xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+	if (!info->is_rt &&
+	    (!xfs_verify_fsbno(mp, irec->br_startblock) ||
+	     !xfs_verify_fsbno(mp, irec->br_startblock +
+				irec->br_blockcount - 1)))
+		xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+
+	/* We don't allow unwritten extents on attr forks. */
+	if (irec->br_state == XFS_EXT_UNWRITTEN &&
+	    info->whichfork == XFS_ATTR_FORK)
+		xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+
+	info->lastoff = irec->br_startoff + irec->br_blockcount;
+	return error;
+}
+
+/* Scrub a bmbt record. */
+STATIC int
+xfs_scrub_bmapbt_rec(
+	struct xfs_scrub_btree		*bs,
+	union xfs_btree_rec		*rec)
+{
+	struct xfs_bmbt_rec_host	ihost;
+	struct xfs_bmbt_irec		irec;
+	struct xfs_scrub_bmap_info	*info = bs->private;
+	struct xfs_inode		*ip = bs->cur->bc_private.b.ip;
+	struct xfs_buf			*bp = NULL;
+	struct xfs_btree_block		*block;
+	uint64_t			owner;
+	int				i;
+
+	/*
+	 * Check the owners of the btree blocks up to the level below
+	 * the root since the verifiers don't do that.
+	 */
+	if (xfs_sb_version_hascrc(&bs->cur->bc_mp->m_sb) &&
+	    bs->cur->bc_ptrs[0] == 1) {
+		for (i = 0; i < bs->cur->bc_nlevels - 1; i++) {
+			block = xfs_btree_get_block(bs->cur, i, &bp);
+			owner = be64_to_cpu(block->bb_u.l.bb_owner);
+			if (owner != ip->i_ino)
+				xfs_scrub_fblock_set_corrupt(bs->sc,
+						info->whichfork, 0);
+		}
+	}
+
+	/* Set up the in-core record and scrub it. */
+	ihost.l0 = be64_to_cpu(rec->bmbt.l0);
+	ihost.l1 = be64_to_cpu(rec->bmbt.l1);
+	xfs_bmbt_get_all(&ihost, &irec);
+	return xfs_scrub_bmap_extent(ip, bs->cur, info, &irec);
+}
+
+/* Scan the btree records. */
+STATIC int
+xfs_scrub_bmap_btree(
+	struct xfs_scrub_context	*sc,
+	int				whichfork,
+	struct xfs_scrub_bmap_info	*info)
+{
+	struct xfs_owner_info		oinfo;
+	struct xfs_mount		*mp = sc->mp;
+	struct xfs_inode		*ip = sc->ip;
+	struct xfs_btree_cur		*cur;
+	int				error;
+
+	cur = xfs_bmbt_init_cursor(mp, sc->tp, ip, whichfork);
+	xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, whichfork);
+	error = xfs_scrub_btree(sc, cur, xfs_scrub_bmapbt_rec, &oinfo, info);
+	xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR :
+					  XFS_BTREE_NOERROR);
+	return error;
+}
+
+/*
+ * Scrub an inode fork's block mappings.
+ *
+ * First we scan every record in every btree block, if applicable.
+ * Then we unconditionally scan the incore extent cache.
+ */
+STATIC int
+xfs_scrub_bmap(
+	struct xfs_scrub_context	*sc,
+	int				whichfork)
+{
+	struct xfs_bmbt_irec		irec;
+	struct xfs_scrub_bmap_info	info = {0};
+	struct xfs_mount		*mp = sc->mp;
+	struct xfs_inode		*ip = sc->ip;
+	struct xfs_ifork		*ifp;
+	xfs_fileoff_t			endoff;
+	xfs_extnum_t			idx;
+	bool				found;
+	int				error = 0;
+
+	ifp = XFS_IFORK_PTR(ip, whichfork);
+
+	info.is_rt = whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip);
+	info.whichfork = whichfork;
+	info.is_shared = whichfork == XFS_DATA_FORK && xfs_is_reflink_inode(ip);
+	info.sc = sc;
+
+	switch (whichfork) {
+	case XFS_COW_FORK:
+		/* Non-existent CoW forks are ignorable. */
+		if (!ifp)
+			goto out;
+		/* No CoW forks on non-reflink inodes/filesystems. */
+		if (!xfs_is_reflink_inode(ip)) {
+			xfs_scrub_ino_set_corrupt(sc, sc->ip->i_ino, NULL);
+			goto out;
+		}
+		break;
+	case XFS_ATTR_FORK:
+		if (!ifp)
+			goto out;
+		if (!xfs_sb_version_hasattr(&mp->m_sb) &&
+		    !xfs_sb_version_hasattr2(&mp->m_sb))
+			xfs_scrub_ino_set_corrupt(sc, sc->ip->i_ino, NULL);
+		break;
+	default:
+		ASSERT(whichfork == XFS_DATA_FORK);
+		break;
+	}
+
+	/* Check the fork values */
+	switch (XFS_IFORK_FORMAT(ip, whichfork)) {
+	case XFS_DINODE_FMT_UUID:
+	case XFS_DINODE_FMT_DEV:
+	case XFS_DINODE_FMT_LOCAL:
+		/* No mappings to check. */
+		goto out;
+	case XFS_DINODE_FMT_EXTENTS:
+		if (!(ifp->if_flags & XFS_IFEXTENTS)) {
+			xfs_scrub_fblock_set_corrupt(sc, whichfork, 0);
+			goto out;
+		}
+		break;
+	case XFS_DINODE_FMT_BTREE:
+		if (whichfork == XFS_COW_FORK) {
+			xfs_scrub_fblock_set_corrupt(sc, whichfork, 0);
+			goto out;
+		}
+
+		error = xfs_scrub_bmap_btree(sc, whichfork, &info);
+		if (error)
+			goto out;
+		break;
+	default:
+		xfs_scrub_fblock_set_corrupt(sc, whichfork, 0);
+		goto out;
+	}
+
+	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
+		goto out;
+
+	/* Now try to scrub the in-memory extent list. */
+        if (!(ifp->if_flags & XFS_IFEXTENTS)) {
+		error = xfs_iread_extents(sc->tp, ip, whichfork);
+		if (!xfs_scrub_fblock_process_error(sc, whichfork, 0, &error))
+			goto out;
+	}
+
+	/* Find the offset of the last extent in the mapping. */
+	error = xfs_bmap_last_offset(ip, &endoff, whichfork);
+	if (!xfs_scrub_fblock_process_error(sc, whichfork, 0, &error))
+		goto out;
+
+	/* Scrub extent records. */
+	info.lastoff = 0;
+	ifp = XFS_IFORK_PTR(ip, whichfork);
+	for (found = xfs_iext_lookup_extent(ip, ifp, 0, &idx, &irec);
+	     found != 0;
+	     found = xfs_iext_get_extent(ifp, ++idx, &irec)) {
+		if (xfs_scrub_should_terminate(sc, &error))
+			break;
+		if (isnullstartblock(irec.br_startblock))
+			continue;
+		if (irec.br_startoff >= endoff) {
+			xfs_scrub_fblock_set_corrupt(sc, whichfork,
+					irec.br_startoff);
+			goto out;
+		}
+		error = xfs_scrub_bmap_extent(ip, NULL, &info, &irec);
+		if (error)
+			goto out;
+	}
+
+out:
+	return error;
+}
+
+/* Scrub an inode's data fork. */
+int
+xfs_scrub_bmap_data(
+	struct xfs_scrub_context	*sc)
+{
+	return xfs_scrub_bmap(sc, XFS_DATA_FORK);
+}
+
+/* Scrub an inode's attr fork. */
+int
+xfs_scrub_bmap_attr(
+	struct xfs_scrub_context	*sc)
+{
+	return xfs_scrub_bmap(sc, XFS_ATTR_FORK);
+}
+
+/* Scrub an inode's CoW fork. */
+int
+xfs_scrub_bmap_cow(
+	struct xfs_scrub_context	*sc)
+{
+	if (!xfs_is_reflink_inode(sc->ip))
+		return -ENOENT;
+
+	return xfs_scrub_bmap(sc, XFS_COW_FORK);
+}