xfs: repair the rmapbt

Rebuild the reverse mapping btree from all primary metadata.  This first
patch establishes the bare mechanics of finding records and putting
together a new ondisk tree; more complex pieces are needed to make it
work properly.

Link: Documentation/filesystems/xfs-online-fsck-design.rst
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/Makefile

@@ -201,6 +201,7 @@ xfs-y				+= $(addprefix scrub/, \
 				   reap.o \
 				   refcount_repair.o \
 				   repair.o \
+				   rmap_repair.o \
 				   )
 
 xfs-$(CONFIG_XFS_RT)		+= $(addprefix scrub/, \

fs/xfs/libxfs/xfs_ag.h

@@ -90,6 +90,7 @@ struct xfs_perag {
 	uint8_t		pagf_repair_bno_level;
 	uint8_t		pagf_repair_cnt_level;
 	uint8_t		pagf_repair_refcount_level;
+	uint8_t		pagf_repair_rmap_level;
 #endif
 
 	spinlock_t	pag_state_lock;

fs/xfs/libxfs/xfs_bmap.c

@@ -6379,3 +6379,46 @@ xfs_bunmapi_range(
 out:
 	return error;
 }
+
+struct xfs_bmap_query_range {
+	xfs_bmap_query_range_fn	fn;
+	void			*priv;
+};
+
+/* Format btree record and pass to our callback. */
+STATIC int
+xfs_bmap_query_range_helper(
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_rec	*rec,
+	void				*priv)
+{
+	struct xfs_bmap_query_range	*query = priv;
+	struct xfs_bmbt_irec		irec;
+	xfs_failaddr_t			fa;
+
+	xfs_bmbt_disk_get_all(&rec->bmbt, &irec);
+	fa = xfs_bmap_validate_extent(cur->bc_ino.ip, cur->bc_ino.whichfork,
+			&irec);
+	if (fa) {
+		xfs_btree_mark_sick(cur);
+		return xfs_bmap_complain_bad_rec(cur->bc_ino.ip,
+				cur->bc_ino.whichfork, fa, &irec);
+	}
+
+	return query->fn(cur, &irec, query->priv);
+}
+
+/* Find all bmaps. */
+int
+xfs_bmap_query_all(
+	struct xfs_btree_cur		*cur,
+	xfs_bmap_query_range_fn		fn,
+	void				*priv)
+{
+	struct xfs_bmap_query_range	query = {
+		.priv			= priv,
+		.fn			= fn,
+	};
+
+	return xfs_btree_query_all(cur, xfs_bmap_query_range_helper, &query);
+}

fs/xfs/libxfs/xfs_bmap.h

@@ -280,4 +280,12 @@ extern struct kmem_cache	*xfs_bmap_intent_cache;
 int __init xfs_bmap_intent_init_cache(void);
 void xfs_bmap_intent_destroy_cache(void);
 
+typedef int (*xfs_bmap_query_range_fn)(
+	struct xfs_btree_cur	*cur,
+	struct xfs_bmbt_irec	*rec,
+	void			*priv);
+
+int xfs_bmap_query_all(struct xfs_btree_cur *cur, xfs_bmap_query_range_fn fn,
+		void *priv);
+
 #endif	/* __XFS_BMAP_H__ */

fs/xfs/libxfs/xfs_rmap.c

@@ -215,10 +215,10 @@ xfs_rmap_btrec_to_irec(
 /* Simple checks for rmap records. */
 xfs_failaddr_t
 xfs_rmap_check_irec(
-	struct xfs_btree_cur		*cur,
+	struct xfs_perag		*pag,
 	const struct xfs_rmap_irec	*irec)
 {
-	struct xfs_mount		*mp = cur->bc_mp;
+	struct xfs_mount		*mp = pag->pag_mount;
 	bool				is_inode;
 	bool				is_unwritten;
 	bool				is_bmbt;
@@ -233,8 +233,8 @@ xfs_rmap_check_irec(
 			return __this_address;
 	} else {
 		/* check for valid extent range, including overflow */
-		if (!xfs_verify_agbext(cur->bc_ag.pag, irec->rm_startblock,
-						       irec->rm_blockcount))
+		if (!xfs_verify_agbext(pag, irec->rm_startblock,
+					    irec->rm_blockcount))
 			return __this_address;
 	}
 
@@ -307,7 +307,7 @@ xfs_rmap_get_rec(
 
 	fa = xfs_rmap_btrec_to_irec(rec, irec);
 	if (!fa)
-		fa = xfs_rmap_check_irec(cur, irec);
+		fa = xfs_rmap_check_irec(cur->bc_ag.pag, irec);
 	if (fa)
 		return xfs_rmap_complain_bad_rec(cur, fa, irec);
 
@@ -2442,7 +2442,7 @@ xfs_rmap_query_range_helper(
 
 	fa = xfs_rmap_btrec_to_irec(rec, &irec);
 	if (!fa)
-		fa = xfs_rmap_check_irec(cur, &irec);
+		fa = xfs_rmap_check_irec(cur->bc_ag.pag, &irec);
 	if (fa)
 		return xfs_rmap_complain_bad_rec(cur, fa, &irec);
 

fs/xfs/libxfs/xfs_rmap.h

@@ -195,7 +195,7 @@ int xfs_rmap_compare(const struct xfs_rmap_irec *a,
 union xfs_btree_rec;
 xfs_failaddr_t xfs_rmap_btrec_to_irec(const union xfs_btree_rec *rec,
 		struct xfs_rmap_irec *irec);
-xfs_failaddr_t xfs_rmap_check_irec(struct xfs_btree_cur *cur,
+xfs_failaddr_t xfs_rmap_check_irec(struct xfs_perag *pag,
 		const struct xfs_rmap_irec *irec);
 
 int xfs_rmap_has_records(struct xfs_btree_cur *cur, xfs_agblock_t bno,

fs/xfs/libxfs/xfs_rmap_btree.c

@@ -342,7 +342,18 @@ xfs_rmapbt_verify(
 
 	level = be16_to_cpu(block->bb_level);
 	if (pag && xfs_perag_initialised_agf(pag)) {
-		if (level >= pag->pagf_rmap_level)
+		unsigned int	maxlevel = pag->pagf_rmap_level;
+
+#ifdef CONFIG_XFS_ONLINE_REPAIR
+		/*
+		 * Online repair could be rewriting the free space btrees, so
+		 * we'll validate against the larger of either tree while this
+		 * is going on.
+		 */
+		maxlevel = max_t(unsigned int, maxlevel,
+				pag->pagf_repair_rmap_level);
+#endif
+		if (level >= maxlevel)
 			return __this_address;
 	} else if (level >= mp->m_rmap_maxlevels)
 		return __this_address;

fs/xfs/scrub/common.c

@@ -460,7 +460,7 @@ xchk_perag_read_headers(
  * Grab the AG headers for the attached perag structure and wait for pending
  * intents to drain.
  */
-static int
+int
 xchk_perag_drain_and_lock(
 	struct xfs_scrub	*sc)
 {

fs/xfs/scrub/common.h

@@ -134,6 +134,7 @@ int xchk_setup_nlinks(struct xfs_scrub *sc);
 void xchk_ag_free(struct xfs_scrub *sc, struct xchk_ag *sa);
 int xchk_ag_init(struct xfs_scrub *sc, xfs_agnumber_t agno,
 		struct xchk_ag *sa);
+int xchk_perag_drain_and_lock(struct xfs_scrub *sc);
 
 /*
  * Grab all AG resources, treating the inability to grab the perag structure as

fs/xfs/scrub/newbt.c

@@ -239,7 +239,11 @@ xrep_newbt_alloc_ag_blocks(
 
 		xrep_newbt_validate_ag_alloc_hint(xnr);
 
-		error = xfs_alloc_vextent_near_bno(&args, xnr->alloc_hint);
+		if (xnr->alloc_vextent)
+			error = xnr->alloc_vextent(sc, &args, xnr->alloc_hint);
+		else
+			error = xfs_alloc_vextent_near_bno(&args,
+					xnr->alloc_hint);
 		if (error)
 			return error;
 		if (args.fsbno == NULLFSBLOCK)
@@ -309,7 +313,11 @@ xrep_newbt_alloc_file_blocks(
 
 		xrep_newbt_validate_file_alloc_hint(xnr);
 
-		error = xfs_alloc_vextent_start_ag(&args, xnr->alloc_hint);
+		if (xnr->alloc_vextent)
+			error = xnr->alloc_vextent(sc, &args, xnr->alloc_hint);
+		else
+			error = xfs_alloc_vextent_start_ag(&args,
+					xnr->alloc_hint);
 		if (error)
 			return error;
 		if (args.fsbno == NULLFSBLOCK)

fs/xfs/scrub/newbt.h

@@ -6,6 +6,8 @@
 #ifndef __XFS_SCRUB_NEWBT_H__
 #define __XFS_SCRUB_NEWBT_H__
 
+struct xfs_alloc_arg;
+
 struct xrep_newbt_resv {
 	/* Link to list of extents that we've reserved. */
 	struct list_head	list;
@@ -28,6 +30,11 @@ struct xrep_newbt_resv {
 struct xrep_newbt {
 	struct xfs_scrub	*sc;
 
+	/* Custom allocation function, or NULL for xfs_alloc_vextent */
+	int			(*alloc_vextent)(struct xfs_scrub *sc,
+						 struct xfs_alloc_arg *args,
+						 xfs_fsblock_t alloc_hint);
+
 	/* List of extents that we've reserved. */
 	struct list_head	resv_list;
 

fs/xfs/scrub/reap.c

@@ -114,7 +114,7 @@ xreap_put_freelist(
 	int			error;
 
 	/* Make sure there's space on the freelist. */
-	error = xrep_fix_freelist(sc, true);
+	error = xrep_fix_freelist(sc, 0);
 	if (error)
 		return error;
 

fs/xfs/scrub/repair.c

@@ -401,7 +401,7 @@ xrep_calc_ag_resblks(
 int
 xrep_fix_freelist(
 	struct xfs_scrub	*sc,
-	bool			can_shrink)
+	int			alloc_flags)
 {
 	struct xfs_alloc_arg	args = {0};
 
@@ -411,8 +411,7 @@ xrep_fix_freelist(
 	args.alignment = 1;
 	args.pag = sc->sa.pag;
 
-	return xfs_alloc_fix_freelist(&args,
-			can_shrink ? 0 : XFS_ALLOC_FLAG_NOSHRINK);
+	return xfs_alloc_fix_freelist(&args, alloc_flags);
 }
 
 /*

fs/xfs/scrub/repair.h

@@ -51,7 +51,7 @@ struct xbitmap;
 struct xagb_bitmap;
 struct xfsb_bitmap;
 
-int xrep_fix_freelist(struct xfs_scrub *sc, bool can_shrink);
+int xrep_fix_freelist(struct xfs_scrub *sc, int alloc_flags);
 
 struct xrep_find_ag_btree {
 	/* in: rmap owner of the btree we're looking for */
@@ -86,6 +86,7 @@ int xrep_ino_ensure_extent_count(struct xfs_scrub *sc, int whichfork,
 int xrep_reset_perag_resv(struct xfs_scrub *sc);
 int xrep_bmap(struct xfs_scrub *sc, int whichfork, bool allow_unwritten);
 int xrep_metadata_inode_forks(struct xfs_scrub *sc);
+int xrep_setup_ag_rmapbt(struct xfs_scrub *sc);
 
 /* Repair setup functions */
 int xrep_setup_ag_allocbt(struct xfs_scrub *sc);
@@ -111,6 +112,7 @@ int xrep_agfl(struct xfs_scrub *sc);
 int xrep_agi(struct xfs_scrub *sc);
 int xrep_allocbt(struct xfs_scrub *sc);
 int xrep_iallocbt(struct xfs_scrub *sc);
+int xrep_rmapbt(struct xfs_scrub *sc);
 int xrep_refcountbt(struct xfs_scrub *sc);
 int xrep_inode(struct xfs_scrub *sc);
 int xrep_bmap_data(struct xfs_scrub *sc);
@@ -177,6 +179,7 @@ xrep_setup_nothing(
 	return 0;
 }
 #define xrep_setup_ag_allocbt		xrep_setup_nothing
+#define xrep_setup_ag_rmapbt		xrep_setup_nothing
 
 #define xrep_setup_inode(sc, imap)	((void)0)
 
@@ -190,6 +193,7 @@ xrep_setup_nothing(
 #define xrep_agi			xrep_notsupported
 #define xrep_allocbt			xrep_notsupported
 #define xrep_iallocbt			xrep_notsupported
+#define xrep_rmapbt			xrep_notsupported
 #define xrep_refcountbt			xrep_notsupported
 #define xrep_inode			xrep_notsupported
 #define xrep_bmap_data			xrep_notsupported

fs/xfs/scrub/rmap.c

@@ -25,6 +25,7 @@
 #include "scrub/btree.h"
 #include "scrub/bitmap.h"
 #include "scrub/agb_bitmap.h"
+#include "scrub/repair.h"
 
 /*
  * Set us up to scrub reverse mapping btrees.
@@ -36,6 +37,14 @@ xchk_setup_ag_rmapbt(
 	if (xchk_need_intent_drain(sc))
 		xchk_fsgates_enable(sc, XCHK_FSGATES_DRAIN);
 
+	if (xchk_could_repair(sc)) {
+		int		error;
+
+		error = xrep_setup_ag_rmapbt(sc);
+		if (error)
+			return error;
+	}
+
 	return xchk_setup_ag_btree(sc, false);
 }
 
@@ -349,7 +358,7 @@ xchk_rmapbt_rec(
 	struct xfs_rmap_irec	irec;
 
 	if (xfs_rmap_btrec_to_irec(rec, &irec) != NULL ||
-	    xfs_rmap_check_irec(bs->cur, &irec) != NULL) {
+	    xfs_rmap_check_irec(bs->cur->bc_ag.pag, &irec) != NULL) {
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 		return 0;
 	}

fs/xfs/scrub/scrub.c

@@ -278,7 +278,7 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
 		.setup	= xchk_setup_ag_rmapbt,
 		.scrub	= xchk_rmapbt,
 		.has	= xfs_has_rmapbt,
-		.repair	= xrep_notsupported,
+		.repair	= xrep_rmapbt,
 	},
 	[XFS_SCRUB_TYPE_REFCNTBT] = {	/* refcountbt */
 		.type	= ST_PERAG,

fs/xfs/scrub/trace.h

@@ -1595,7 +1595,6 @@ DEFINE_EVENT(xrep_rmap_class, name, \
 		 uint64_t owner, uint64_t offset, unsigned int flags), \
 	TP_ARGS(mp, agno, agbno, len, owner, offset, flags))
 DEFINE_REPAIR_RMAP_EVENT(xrep_ibt_walk_rmap);
-DEFINE_REPAIR_RMAP_EVENT(xrep_rmap_extent_fn);
 DEFINE_REPAIR_RMAP_EVENT(xrep_bmap_walk_rmap);
 
 TRACE_EVENT(xrep_abt_found,
@@ -1713,6 +1712,38 @@ TRACE_EVENT(xrep_bmap_found,
 		  __entry->state)
 );
 
+TRACE_EVENT(xrep_rmap_found,
+	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno,
+		 const struct xfs_rmap_irec *rec),
+	TP_ARGS(mp, agno, rec),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_agblock_t, agbno)
+		__field(xfs_extlen_t, len)
+		__field(uint64_t, owner)
+		__field(uint64_t, offset)
+		__field(unsigned int, flags)
+	),
+	TP_fast_assign(
+		__entry->dev = mp->m_super->s_dev;
+		__entry->agno = agno;
+		__entry->agbno = rec->rm_startblock;
+		__entry->len = rec->rm_blockcount;
+		__entry->owner = rec->rm_owner;
+		__entry->offset = rec->rm_offset;
+		__entry->flags = rec->rm_flags;
+	),
+	TP_printk("dev %d:%d agno 0x%x agbno 0x%x fsbcount 0x%x owner 0x%llx fileoff 0x%llx flags 0x%x",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->agno,
+		  __entry->agbno,
+		  __entry->len,
+		  __entry->owner,
+		  __entry->offset,
+		  __entry->flags)
+);
+
 TRACE_EVENT(xrep_findroot_block,
 	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, xfs_agblock_t agbno,
 		 uint32_t magic, uint16_t level),