[PATCH v2 18/30] xfs: scrub inode btrees

["Darrick J. Wong" <darrick.wong@oracle.com>]

Check the records of the inode btrees to make sure that the values
make sense given the inode records themselves.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
v2: fix insane freemask variable usage, shorten helper function names
---
 fs/xfs/Makefile            |    1 
 fs/xfs/libxfs/xfs_format.h |    2 
 fs/xfs/libxfs/xfs_fs.h     |    4 -
 fs/xfs/scrub/common.c      |   29 ++++
 fs/xfs/scrub/common.h      |    3 
 fs/xfs/scrub/ialloc.c      |  334 ++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/scrub/scrub.c       |    9 +
 fs/xfs/scrub/scrub.h       |    2 
 8 files changed, 382 insertions(+), 2 deletions(-)
 create mode 100644 fs/xfs/scrub/ialloc.c

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 84ac733..82326b7 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -150,6 +150,7 @@ xfs-y				+= $(addprefix scrub/, \
 				   alloc.o \
 				   btree.o \
 				   common.o \
+				   ialloc.o \
 				   scrub.o \
 				   )
 endif
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 23229f0..154c3dd 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -518,7 +518,7 @@ static inline int xfs_sb_version_hasftype(struct xfs_sb *sbp)
 		 (sbp->sb_features2 & XFS_SB_VERSION2_FTYPE));
 }
 
-static inline int xfs_sb_version_hasfinobt(xfs_sb_t *sbp)
+static inline bool xfs_sb_version_hasfinobt(xfs_sb_t *sbp)
 {
 	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) &&
 		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_FINOBT);
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 1e23d13..74df6ec 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -490,9 +490,11 @@ struct xfs_scrub_metadata {
 #define XFS_SCRUB_TYPE_AGI	4	/* AG inode header */
 #define XFS_SCRUB_TYPE_BNOBT	5	/* freesp by block btree */
 #define XFS_SCRUB_TYPE_CNTBT	6	/* freesp by length btree */
+#define XFS_SCRUB_TYPE_INOBT	7	/* inode btree */
+#define XFS_SCRUB_TYPE_FINOBT	8	/* free inode btree */
 
 /* Number of scrub subcommands. */
-#define XFS_SCRUB_TYPE_NR	7
+#define XFS_SCRUB_TYPE_NR	9
 
 /* i: Repair this metadata. */
 #define XFS_SCRUB_IFLAG_REPAIR		(1 << 0)
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index 018127a..39165c3 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -40,6 +40,8 @@
 #include "xfs_refcount_btree.h"
 #include "xfs_rmap.h"
 #include "xfs_rmap_btree.h"
+#include "xfs_log.h"
+#include "xfs_trans_priv.h"
 #include "scrub/xfs_scrub.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
@@ -451,11 +453,38 @@ xfs_scrub_setup_ag_btree(
 	struct xfs_inode		*ip,
 	bool				force_log)
 {
+	struct xfs_mount		*mp = sc->mp;
 	int				error;
 
+	/*
+	 * If the caller asks us to checkpont the log, do so.  This
+	 * expensive operation should be performed infrequently and only
+	 * as a last resort.  Any caller that sets force_log should
+	 * document why they need to do so.
+	 */
+	if (force_log) {
+		error = xfs_scrub_checkpoint_log(mp);
+		if (error)
+			return error;
+	}
+
 	error = xfs_scrub_setup_ag_header(sc, ip);
 	if (error)
 		return error;
 
 	return xfs_scrub_ag_init(sc, sc->sm->sm_agno, &sc->sa);
 }
+
+/* Push everything out of the log onto disk. */
+int
+xfs_scrub_checkpoint_log(
+	struct xfs_mount	*mp)
+{
+	int			error;
+
+	error = _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
+	if (error)
+		return error;
+	xfs_ail_push_all_sync(mp->m_ail);
+	return 0;
+}
diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h
index 372a844..17830b8 100644
--- a/fs/xfs/scrub/common.h
+++ b/fs/xfs/scrub/common.h
@@ -73,6 +73,7 @@ void xfs_scrub_fblock_set_warning(struct xfs_scrub_context *sc, int whichfork,
 		xfs_fileoff_t offset);
 
 void xfs_scrub_set_incomplete(struct xfs_scrub_context *sc);
+int xfs_scrub_checkpoint_log(struct xfs_mount *mp);
 
 /* Setup functions */
 int xfs_scrub_setup_fs(struct xfs_scrub_context *sc, struct xfs_inode *ip);
@@ -80,6 +81,8 @@ int xfs_scrub_setup_ag_header(struct xfs_scrub_context *sc,
 			      struct xfs_inode *ip);
 int xfs_scrub_setup_ag_allocbt(struct xfs_scrub_context *sc,
 			       struct xfs_inode *ip);
+int xfs_scrub_setup_ag_iallocbt(struct xfs_scrub_context *sc,
+				struct xfs_inode *ip);
 
 
 void xfs_scrub_ag_free(struct xfs_scrub_context *sc, struct xfs_scrub_ag *sa);
diff --git a/fs/xfs/scrub/ialloc.c b/fs/xfs/scrub/ialloc.c
new file mode 100644
index 0000000..90e7911
--- /dev/null
+++ b/fs/xfs/scrub/ialloc.c
@@ -0,0 +1,334 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "xfs_ialloc.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_icache.h"
+#include "xfs_rmap.h"
+#include "xfs_log.h"
+#include "xfs_trans_priv.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 to scrub inode btrees.
+ * If we detect a discrepancy between the inobt and the inode,
+ * try again after forcing logged inode cores out to disk.
+ */
+int
+xfs_scrub_setup_ag_iallocbt(
+	struct xfs_scrub_context	*sc,
+	struct xfs_inode		*ip)
+{
+	return xfs_scrub_setup_ag_btree(sc, ip, sc->try_harder);
+}
+
+/* Inode btree scrubber. */
+
+/* Is this chunk worth checking? */
+STATIC bool
+xfs_scrub_iallocbt_chunk(
+	struct xfs_scrub_btree		*bs,
+	struct xfs_inobt_rec_incore	*irec,
+	xfs_agino_t			agino,
+	xfs_extlen_t			len)
+{
+	struct xfs_mount		*mp = bs->cur->bc_mp;
+	xfs_agnumber_t			agno = bs->cur->bc_private.a.agno;
+	xfs_agblock_t			bno;
+
+	bno = XFS_AGINO_TO_AGBNO(mp, agino);
+	if (bno + len <= bno ||
+	    !xfs_verify_agbno(mp, agno, bno) ||
+	    !xfs_verify_agbno(mp, agno, bno + len - 1))
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+	return true;
+}
+
+/* Count the number of free inodes. */
+static unsigned int
+xfs_scrub_iallocbt_freecount(
+	xfs_inofree_t			freemask)
+{
+	BUILD_BUG_ON(sizeof(freemask) != sizeof(__u64));
+	return hweight64(freemask);
+}
+
+/* Check a particular inode with ir_free. */
+STATIC int
+xfs_scrub_iallocbt_check_cluster_freemask(
+	struct xfs_scrub_btree		*bs,
+	xfs_ino_t			fsino,
+	xfs_agino_t			chunkino,
+	xfs_agino_t			clusterino,
+	struct xfs_inobt_rec_incore	*irec,
+	struct xfs_buf			*bp)
+{
+	struct xfs_dinode		*dip;
+	struct xfs_mount		*mp = bs->cur->bc_mp;
+	bool				inode_is_free = false;
+	bool				freemask_ok;
+	bool				inuse;
+	int				error;
+
+	dip = xfs_buf_offset(bp, clusterino * mp->m_sb.sb_inodesize);
+	if (be16_to_cpu(dip->di_magic) != XFS_DINODE_MAGIC ||
+	    (dip->di_version >= 3 &&
+	     be64_to_cpu(dip->di_ino) != fsino + clusterino)) {
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+		goto out;
+	}
+
+	if (irec->ir_free & XFS_INOBT_MASK(chunkino + clusterino))
+		inode_is_free = true;
+	error = xfs_icache_inode_is_allocated(mp, bs->cur->bc_tp,
+			fsino + clusterino, &inuse);
+	if (error == -ENODATA) {
+		/* Not cached, just read the disk buffer */
+		freemask_ok = inode_is_free ^ !!(dip->di_mode);
+		if (!bs->sc->try_harder && !freemask_ok)
+			return -EDEADLOCK;
+	} else if (error < 0) {
+		/*
+		 * Inode is only half assembled, or there was an IO error,
+		 * or the verifier failed, so don't bother trying to check.
+		 * The inode scrubber can deal with this.
+		 */
+		goto out;
+	} else {
+		/* Inode is all there. */
+		freemask_ok = inode_is_free ^ inuse;
+	}
+	if (!freemask_ok)
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+out:
+	return 0;
+}
+
+/* Make sure the free mask is consistent with what the inodes think. */
+STATIC int
+xfs_scrub_iallocbt_check_freemask(
+	struct xfs_scrub_btree		*bs,
+	struct xfs_inobt_rec_incore	*irec)
+{
+	struct xfs_owner_info		oinfo;
+	struct xfs_imap			imap;
+	struct xfs_mount		*mp = bs->cur->bc_mp;
+	struct xfs_dinode		*dip;
+	struct xfs_buf			*bp;
+	xfs_ino_t			fsino;
+	xfs_agino_t			nr_inodes;
+	xfs_agino_t			agino;
+	xfs_agino_t			chunkino;
+	xfs_agino_t			clusterino;
+	xfs_agblock_t			agbno;
+	int				blks_per_cluster;
+	uint16_t			holemask;
+	uint16_t			ir_holemask;
+	int				error = 0;
+
+	/* Make sure the freemask matches the inode records. */
+	blks_per_cluster = xfs_icluster_size_fsb(mp);
+	nr_inodes = XFS_OFFBNO_TO_AGINO(mp, blks_per_cluster, 0);
+	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_INODES);
+
+	for (agino = irec->ir_startino;
+	     agino < irec->ir_startino + XFS_INODES_PER_CHUNK;
+	     agino += blks_per_cluster * mp->m_sb.sb_inopblock) {
+		fsino = XFS_AGINO_TO_INO(mp, bs->cur->bc_private.a.agno, agino);
+		chunkino = agino - irec->ir_startino;
+		agbno = XFS_AGINO_TO_AGBNO(mp, agino);
+
+		/* Compute the holemask mask for this cluster. */
+		for (clusterino = 0, holemask = 0; clusterino < nr_inodes;
+		     clusterino += XFS_INODES_PER_HOLEMASK_BIT)
+			holemask |= XFS_INOBT_MASK((chunkino + clusterino) /
+					XFS_INODES_PER_HOLEMASK_BIT);
+
+		/* The whole cluster must be a hole or not a hole. */
+		ir_holemask = (irec->ir_holemask & holemask);
+		if (ir_holemask != holemask && ir_holemask != 0) {
+			xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+			continue;
+		}
+
+		/* If any part of this is a hole, skip it. */
+		if (ir_holemask)
+			continue;
+
+		/* Grab the inode cluster buffer. */
+		imap.im_blkno = XFS_AGB_TO_DADDR(mp, bs->cur->bc_private.a.agno,
+				agbno);
+		imap.im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
+		imap.im_boffset = 0;
+
+		error = xfs_imap_to_bp(mp, bs->cur->bc_tp, &imap,
+				&dip, &bp, 0, 0);
+		if (!xfs_scrub_btree_process_error(bs->sc, bs->cur, 0, &error))
+			continue;
+
+		/* Which inodes are free? */
+		for (clusterino = 0; clusterino < nr_inodes; clusterino++) {
+			error = xfs_scrub_iallocbt_check_cluster_freemask(bs,
+					fsino, chunkino, clusterino, irec, bp);
+			if (error) {
+				xfs_trans_brelse(bs->cur->bc_tp, bp);
+				return error;
+			}
+		}
+
+		xfs_trans_brelse(bs->cur->bc_tp, bp);
+	}
+
+	return error;
+}
+
+/* Scrub an inobt/finobt record. */
+STATIC int
+xfs_scrub_iallocbt_rec(
+	struct xfs_scrub_btree		*bs,
+	union xfs_btree_rec		*rec)
+{
+	struct xfs_mount		*mp = bs->cur->bc_mp;
+	struct xfs_inobt_rec_incore	irec;
+	uint64_t			holes;
+	xfs_agnumber_t			agno = bs->cur->bc_private.a.agno;
+	xfs_agino_t			agino;
+	xfs_agblock_t			agbno;
+	xfs_extlen_t			len;
+	int				holecount;
+	int				i;
+	int				error = 0;
+	unsigned int			real_freecount;
+	uint16_t			holemask;
+
+	xfs_inobt_btrec_to_irec(mp, rec, &irec);
+
+	if (irec.ir_count > XFS_INODES_PER_CHUNK ||
+	    irec.ir_freecount > XFS_INODES_PER_CHUNK)
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+	real_freecount = irec.ir_freecount +
+			(XFS_INODES_PER_CHUNK - irec.ir_count);
+	if (real_freecount != xfs_scrub_iallocbt_freecount(irec.ir_free))
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+	agino = irec.ir_startino;
+	/* Record has to be properly aligned within the AG. */
+	if (!xfs_verify_agino(mp, agno, agino) ||
+	    !xfs_verify_agino(mp, agno, agino + XFS_INODES_PER_CHUNK - 1)) {
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+		goto out;
+	}
+
+	/* Make sure this record is aligned to cluster and inoalignmnt size. */
+	agbno = XFS_AGINO_TO_AGBNO(mp, irec.ir_startino);
+	if ((agbno & (xfs_ialloc_cluster_alignment(mp) - 1)) ||
+	    (agbno & (xfs_icluster_size_fsb(mp) - 1)))
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+	/* Handle non-sparse inodes */
+	if (!xfs_inobt_issparse(irec.ir_holemask)) {
+		len = XFS_B_TO_FSB(mp,
+				XFS_INODES_PER_CHUNK * mp->m_sb.sb_inodesize);
+		if (irec.ir_count != XFS_INODES_PER_CHUNK)
+			xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+		if (!xfs_scrub_iallocbt_chunk(bs, &irec, agino, len))
+			goto out;
+		goto check_freemask;
+	}
+
+	/* Check each chunk of a sparse inode cluster. */
+	holemask = irec.ir_holemask;
+	holecount = 0;
+	len = XFS_B_TO_FSB(mp,
+			XFS_INODES_PER_HOLEMASK_BIT * mp->m_sb.sb_inodesize);
+	holes = ~xfs_inobt_irec_to_allocmask(&irec);
+	if ((holes & irec.ir_free) != holes ||
+	    irec.ir_freecount > irec.ir_count)
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+	for (i = 0; i < XFS_INOBT_HOLEMASK_BITS; i++) {
+		if (holemask & 1)
+			holecount += XFS_INODES_PER_HOLEMASK_BIT;
+		else if (!xfs_scrub_iallocbt_chunk(bs, &irec, agino, len))
+			break;
+		holemask >>= 1;
+		agino += XFS_INODES_PER_HOLEMASK_BIT;
+	}
+
+	if (holecount > XFS_INODES_PER_CHUNK ||
+	    holecount + irec.ir_count != XFS_INODES_PER_CHUNK)
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, 0);
+
+check_freemask:
+	error = xfs_scrub_iallocbt_check_freemask(bs, &irec);
+	if (error)
+		goto out;
+
+out:
+	return error;
+}
+
+/* Scrub the inode btrees for some AG. */
+STATIC int
+xfs_scrub_iallocbt(
+	struct xfs_scrub_context	*sc,
+	xfs_btnum_t			which)
+{
+	struct xfs_btree_cur		*cur;
+	struct xfs_owner_info		oinfo;
+
+	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_INOBT);
+	cur = which == XFS_BTNUM_INO ? sc->sa.ino_cur : sc->sa.fino_cur;
+	return xfs_scrub_btree(sc, cur, xfs_scrub_iallocbt_rec, &oinfo, NULL);
+}
+
+int
+xfs_scrub_inobt(
+	struct xfs_scrub_context	*sc)
+{
+	return xfs_scrub_iallocbt(sc, XFS_BTNUM_INO);
+}
+
+int
+xfs_scrub_finobt(
+	struct xfs_scrub_context	*sc)
+{
+	return xfs_scrub_iallocbt(sc, XFS_BTNUM_FINO);
+}
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index d69ab7f..3c04913 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -182,6 +182,15 @@ static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
 		.setup	= xfs_scrub_setup_ag_allocbt,
 		.scrub	= xfs_scrub_cntbt,
 	},
+	{ /* inobt */
+		.setup	= xfs_scrub_setup_ag_iallocbt,
+		.scrub	= xfs_scrub_inobt,
+	},
+	{ /* finobt */
+		.setup	= xfs_scrub_setup_ag_iallocbt,
+		.scrub	= xfs_scrub_finobt,
+		.has	= xfs_sb_version_hasfinobt,
+	},
 };
 
 /* This isn't a stable feature, warn once per day. */
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index a4af99c..5d97453 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -73,5 +73,7 @@ int xfs_scrub_agfl(struct xfs_scrub_context *sc);
 int xfs_scrub_agi(struct xfs_scrub_context *sc);
 int xfs_scrub_bnobt(struct xfs_scrub_context *sc);
 int xfs_scrub_cntbt(struct xfs_scrub_context *sc);
+int xfs_scrub_inobt(struct xfs_scrub_context *sc);
+int xfs_scrub_finobt(struct xfs_scrub_context *sc);
 
 #endif	/* __XFS_SCRUB_SCRUB_H__ */