[PATCH 5/5] xfs: repair refcount btrees

Darrick J. Wong
2023-07-27T22:31:41Z

Reconstruct the refcount data from the rmap btree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/Makefile | 1
fs/xfs/libxfs/xfs_ag.h | 1
fs/xfs/libxfs/xfs_btree.c | 26 +
fs/xfs/libxfs/xfs_btree.h | 2
fs/xfs/libxfs/xfs_refcount.c | 18 +
fs/xfs/libxfs/xfs_refcount.h | 2
fs/xfs/libxfs/xfs_refcount_btree.c | 13 +
fs/xfs/scrub/refcount_repair.c | 796 ++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/repair.h | 2
fs/xfs/scrub/scrub.c | 2
fs/xfs/scrub/trace.h | 22 +
11 files changed, 867 insertions(+), 18 deletions(-)
create mode 100644 fs/xfs/scrub/refcount_repair.c

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 7fed0e706cfa0..a6f708dc56cc2 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -185,6 +185,7 @@ xfs-y += $(addprefix scrub/, \
ialloc_repair.o \
newbt.o \
reap.o \
+ refcount_repair.o \
repair.o \
)
endif
diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h
index 686f4eadd5743..616812911a23f 100644
--- a/fs/xfs/libxfs/xfs_ag.h
+++ b/fs/xfs/libxfs/xfs_ag.h
@@ -87,6 +87,7 @@ struct xfs_perag {
* verifiers while rebuilding the AG btrees.
*/
uint8_t pagf_alt_levels[XFS_BTNUM_AGF];
+ uint8_t pagf_alt_refcount_level;
#endif

spinlock_t pag_state_lock;
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index c100e92140be1..ea8d3659df208 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -5212,3 +5212,29 @@ xfs_btree_destroy_cur_caches(void)
xfs_rmapbt_destroy_cur_cache();
xfs_refcountbt_destroy_cur_cache();
}
+
+/* Move the btree cursor before the first record. */
+int
+xfs_btree_goto_left_edge(
+ struct xfs_btree_cur *cur)
+{
+ int stat = 0;
+ int error;
+
+ memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
+ error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
+ if (error)
+ return error;
+ if (!stat)
+ return 0;
+
+ error = xfs_btree_decrement(cur, 0, &stat);
+ if (error)
+ return error;
+ if (stat != 0) {
+ ASSERT(0);
+ return -EFSCORRUPTED;
+ }
+
+ return 0;
+}
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index e0875cec49392..d906324e25c86 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -738,4 +738,6 @@ xfs_btree_alloc_cursor(
int __init xfs_btree_init_cur_caches(void);
void xfs_btree_destroy_cur_caches(void);

+int xfs_btree_goto_left_edge(struct xfs_btree_cur *cur);
+
#endif /* __XFS_BTREE_H__ */
diff --git a/fs/xfs/libxfs/xfs_refcount.c b/fs/xfs/libxfs/xfs_refcount.c
index 646b3fa362ad0..8db7b6163e55f 100644
--- a/fs/xfs/libxfs/xfs_refcount.c
+++ b/fs/xfs/libxfs/xfs_refcount.c
@@ -120,14 +120,11 @@ xfs_refcount_btrec_to_irec(
irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount);
}

-/* Simple checks for refcount records. */
-xfs_failaddr_t
-xfs_refcount_check_irec(
- struct xfs_btree_cur *cur,
+inline xfs_failaddr_t
+xfs_refcount_check_perag_irec(
+ struct xfs_perag *pag,
const struct xfs_refcount_irec *irec)
{
- struct xfs_perag *pag = cur->bc_ag.pag;
-
if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)
return __this_address;

@@ -144,6 +141,15 @@ xfs_refcount_check_irec(
return NULL;
}

+/* Simple checks for refcount records. */
+xfs_failaddr_t
+xfs_refcount_check_irec(
+ struct xfs_btree_cur *cur,
+ const struct xfs_refcount_irec *irec)
+{
+ return xfs_refcount_check_perag_irec(cur->bc_ag.pag, irec);
+}
+
static inline int
xfs_refcount_complain_bad_rec(
struct xfs_btree_cur *cur,
diff --git a/fs/xfs/libxfs/xfs_refcount.h b/fs/xfs/libxfs/xfs_refcount.h
index 783cd89ca1951..2d6fecb258bb1 100644
--- a/fs/xfs/libxfs/xfs_refcount.h
+++ b/fs/xfs/libxfs/xfs_refcount.h
@@ -117,6 +117,8 @@ extern int xfs_refcount_has_records(struct xfs_btree_cur *cur,
union xfs_btree_rec;
extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
struct xfs_refcount_irec *irec);
+xfs_failaddr_t xfs_refcount_check_perag_irec(struct xfs_perag *pag,
+ const struct xfs_refcount_irec *irec);
xfs_failaddr_t xfs_refcount_check_irec(struct xfs_btree_cur *cur,
const struct xfs_refcount_irec *irec);
extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index 5c3987d8dc242..50fe789efc938 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -226,7 +226,18 @@ xfs_refcountbt_verify(

level = be16_to_cpu(block->bb_level);
if (pag && xfs_perag_initialised_agf(pag)) {
- if (level >= pag->pagf_refcount_level)
+ unsigned int maxlevel = pag->pagf_refcount_level;
+
+#ifdef CONFIG_XFS_ONLINE_REPAIR
+ /*
+ * Online repair could be rewriting the refcount btree, so
+ * we'll validate against the larger of either tree while this
+ * is going on.
+ */
+ maxlevel = max_t(unsigned int, maxlevel,
+ pag->pagf_alt_refcount_level);
+#endif
+ if (level >= maxlevel)
return __this_address;
} else if (level >= mp->m_refc_maxlevels)
return __this_address;
diff --git a/fs/xfs/scrub/refcount_repair.c b/fs/xfs/scrub/refcount_repair.c
new file mode 100644
index 0000000000000..23d0dacc1d15a
--- /dev/null
+++ b/fs/xfs/scrub/refcount_repair.c
@@ -0,0 +1,796 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2018-2023 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#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_btree_staging.h"
+#include "xfs_inode.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_alloc.h"
+#include "xfs_ialloc.h"
+#include "xfs_rmap.h"
+#include "xfs_rmap_btree.h"
+#include "xfs_refcount.h"
+#include "xfs_refcount_btree.h"
+#include "xfs_error.h"
+#include "xfs_ag.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/btree.h"
+#include "scrub/trace.h"
+#include "scrub/repair.h"
+#include "scrub/bitmap.h"
+#include "scrub/xfile.h"
+#include "scrub/xfarray.h"
+#include "scrub/newbt.h"
+#include "scrub/reap.h"
+
+/*
+ * Rebuilding the Reference Count Btree
+ * ====================================
+ *
+ * This algorithm is "borrowed" from xfs_repair. Imagine the rmap
+ * entries as rectangles representing extents of physical blocks, and
+ * that the rectangles can be laid down to allow them to overlap each
+ * other; then we know that we must emit a refcnt btree entry wherever
+ * the amount of overlap changes, i.e. the emission stimulus is
+ * level-triggered:
+ *
+ * - ---
+ * -- ----- ---- --- ------
+ * -- ---- ----------- ---- ---------
+ * -------------------------------- -----------
+ * ^ ^ ^^ ^^ ^ ^^ ^^^ ^^^^ ^ ^^ ^ ^ ^
+ * 2 1 23 21 3 43 234 2123 1 01 2 3 0
+ *
+ * For our purposes, a rmap is a tuple (startblock, len, fileoff, owner).
+ *
+ * Note that in the actual refcnt btree we don't store the refcount < 2
+ * cases because the bnobt tells us which blocks are free; single-use
+ * blocks aren't recorded in the bnobt or the refcntbt. If the rmapbt
+ * supports storing multiple entries covering a given block we could
+ * theoretically dispense with the refcntbt and simply count rmaps, but
+ * that's inefficient in the (hot) write path, so we'll take the cost of
+ * the extra tree to save time. Also there's no guarantee that rmap
+ * will be enabled.
+ *
+ * Given an array of rmaps sorted by physical block number, a starting
+ * physical block (sp), a bag to hold rmaps that cover sp, and the next
+ * physical block where the level changes (np), we can reconstruct the
+ * refcount btree as follows:
+ *
+ * While there are still unprocessed rmaps in the array,
+ * - Set sp to the physical block (pblk) of the next unprocessed rmap.
+ * - Add to the bag all rmaps in the array where startblock == sp.
+ * - Set np to the physical block where the bag size will change. This
+ * is the minimum of (the pblk of the next unprocessed rmap) and
+ * (startblock + len of each rmap in the bag).
+ * - Record the bag size as old_bag_size.
+ *
+ * - While the bag isn't empty,
+ * - Remove from the bag all rmaps where startblock + len == np.
+ * - Add to the bag all rmaps in the array where startblock == np.
+ * - If the bag size isn't old_bag_size, store the refcount entry
+ * (sp, np - sp, bag_size) in the refcnt btree.
+ * - If the bag is empty, break out of the inner loop.
+ * - Set old_bag_size to the bag size
+ * - Set sp = np.
+ * - Set np to the physical block where the bag size will change.
+ * This is the minimum of (the pblk of the next unprocessed rmap)
+ * and (startblock + len of each rmap in the bag).
+ *
+ * Like all the other repairers, we make a list of all the refcount
+ * records we need, then reinitialize the refcount btree root and
+ * insert all the records.
+ */
+
+/* The only parts of the rmap that we care about for computing refcounts. */
+struct xrep_refc_rmap {
+ xfs_agblock_t startblock;
+ xfs_extlen_t blockcount;
+} __packed;
+
+struct xrep_refc {
+ /* refcount extents */
+ struct xfarray *refcount_records;
+
+ /* new refcountbt information */
+ struct xrep_newbt new_btree;
+
+ /* old refcountbt blocks */
+ struct xagb_bitmap old_refcountbt_blocks;
+
+ struct xfs_scrub *sc;
+
+ /* get_records()'s position in the refcount record array. */
+ xfarray_idx_t array_cur;
+
+ /* # of refcountbt blocks */
+ xfs_extlen_t btblocks;
+};
+
+/* Check for any obvious conflicts with this shared/CoW staging extent. */
+STATIC int
+xrep_refc_check_ext(
+ struct xfs_scrub *sc,
+ const struct xfs_refcount_irec *rec)
+{
+ enum xbtree_recpacking outcome;
+ int error;
+
+ if (xfs_refcount_check_perag_irec(sc->sa.pag, rec) != NULL)
+ return -EFSCORRUPTED;
+
+ /* Make sure this isn't free space. */
+ error = xfs_alloc_has_records(sc->sa.bno_cur, rec->rc_startblock,
+ rec->rc_blockcount, &outcome);
+ if (error)
+ return error;
+ if (outcome != XBTREE_RECPACKING_EMPTY)
+ return -EFSCORRUPTED;
+
+ /* Must not be an inode chunk. */
+ error = xfs_ialloc_has_inodes_at_extent(sc->sa.ino_cur,
+ rec->rc_startblock, rec->rc_blockcount, &outcome);
+ if (error)
+ return error;
+ if (outcome != XBTREE_RECPACKING_EMPTY)
+ return -EFSCORRUPTED;
+
+ return 0;
+}
+
+/* Record a reference count extent. */
+STATIC int
+xrep_refc_stash(
+ struct xrep_refc *rr,
+ enum xfs_refc_domain domain,
+ xfs_agblock_t agbno,
+ xfs_extlen_t len,
+ uint64_t refcount)
+{
+ struct xfs_refcount_irec irec = {
+ .rc_startblock = agbno,
+ .rc_blockcount = len,
+ .rc_domain = domain,
+ };
+ struct xfs_scrub *sc = rr->sc;
+ int error = 0;
+
+ if (xchk_should_terminate(sc, &error))
+ return error;
+
+ irec.rc_refcount = min_t(uint64_t, MAXREFCOUNT, refcount);
+
+ error = xrep_refc_check_ext(rr->sc, &irec);
+ if (error)
+ return error;
+
+ trace_xrep_refc_found(sc->sa.pag, &irec);
+
+ return xfarray_append(rr->refcount_records, &irec);
+}
+
+/* Record a CoW staging extent. */
+STATIC int
+xrep_refc_stash_cow(
+ struct xrep_refc *rr,
+ xfs_agblock_t agbno,
+ xfs_extlen_t len)
+{
+ return xrep_refc_stash(rr, XFS_REFC_DOMAIN_COW, agbno, len, 1);
+}
+
+/* Decide if an rmap could describe a shared extent. */
+static inline bool
+xrep_refc_rmap_shareable(
+ struct xfs_mount *mp,
+ const struct xfs_rmap_irec *rmap)
+{
+ /* AG metadata are never sharable */
+ if (XFS_RMAP_NON_INODE_OWNER(rmap->rm_owner))
+ return false;
+
+ /* Metadata in files are never shareable */
+ if (xfs_internal_inum(mp, rmap->rm_owner))
+ return false;
+
+ /* Metadata and unwritten file blocks are not shareable. */
+ if (rmap->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK |
+ XFS_RMAP_UNWRITTEN))
+ return false;
+
+ return true;
+}
+
+/*
+ * Walk along the reverse mapping records until we find one that could describe
+ * a shared extent.
+ */
+STATIC int
+xrep_refc_walk_rmaps(
+ struct xrep_refc *rr,
+ struct xrep_refc_rmap *rrm,
+ bool *have_rec)
+{
+ struct xfs_rmap_irec rmap;
+ struct xfs_btree_cur *cur = rr->sc->sa.rmap_cur;
+ struct xfs_mount *mp = cur->bc_mp;
+ int have_gt;
+ int error = 0;
+
+ *have_rec = false;
+
+ /*
+ * Loop through the remaining rmaps. Remember CoW staging
+ * extents and the refcountbt blocks from the old tree for later
+ * disposal. We can only share written data fork extents, so
+ * keep looping until we find an rmap for one.
+ */
+ do {
+ if (xchk_should_terminate(rr->sc, &error))
+ return error;
+
+ error = xfs_btree_increment(cur, 0, &have_gt);
+ if (error)
+ return error;
+ if (!have_gt)
+ return 0;
+
+ error = xfs_rmap_get_rec(cur, &rmap, &have_gt);
+ if (error)
+ return error;
+ if (XFS_IS_CORRUPT(mp, !have_gt))
+ return -EFSCORRUPTED;
+
+ if (rmap.rm_owner == XFS_RMAP_OWN_COW) {
+ error = xrep_refc_stash_cow(rr, rmap.rm_startblock,
+ rmap.rm_blockcount);
+ if (error)
+ return error;
+ } else if (rmap.rm_owner == XFS_RMAP_OWN_REFC) {
+ /* refcountbt block, dump it when we're done. */
+ rr->btblocks += rmap.rm_blockcount;
+ error = xagb_bitmap_set(&rr->old_refcountbt_blocks,
+ rmap.rm_startblock, rmap.rm_blockcount);
+ if (error)
+ return error;
+ }
+ } while (!xrep_refc_rmap_shareable(mp, &rmap));
+
+ rrm->startblock = rmap.rm_startblock;
+ rrm->blockcount = rmap.rm_blockcount;
+ *have_rec = true;
+ return 0;
+}
+
+static inline uint32_t
+xrep_refc_encode_startblock(
+ const struct xfs_refcount_irec *irec)
+{
+ uint32_t start;
+
+ start = irec->rc_startblock & ~XFS_REFC_COWFLAG;
+ if (irec->rc_domain == XFS_REFC_DOMAIN_COW)
+ start |= XFS_REFC_COWFLAG;
+
+ return start;
+}
+
+/* Sort in the same order as the ondisk records. */
+static int
+xrep_refc_extent_cmp(
+ const void *a,
+ const void *b)
+{
+ const struct xfs_refcount_irec *ap = a;
+ const struct xfs_refcount_irec *bp = b;
+ uint32_t sa, sb;
+
+ sa = xrep_refc_encode_startblock(ap);
+ sb = xrep_refc_encode_startblock(bp);
+
+ if (sa > sb)
+ return 1;
+ if (sa < sb)
+ return -1;
+ return 0;
+}
+
+/*
+ * Sort the refcount extents by startblock or else the btree records will be in
+ * the wrong order. Make sure the records do not overlap in physical space.
+ */
+STATIC int
+xrep_refc_sort_records(
+ struct xrep_refc *rr)
+{
+ struct xfs_refcount_irec irec;
+ xfarray_idx_t cur;
+ enum xfs_refc_domain dom = XFS_REFC_DOMAIN_SHARED;
+ xfs_agblock_t next_agbno = 0;
+ int error;
+
+ error = xfarray_sort(rr->refcount_records, xrep_refc_extent_cmp,
+ XFARRAY_SORT_KILLABLE);
+ if (error)
+ return error;
+
+ foreach_xfarray_idx(rr->refcount_records, cur) {
+ if (xchk_should_terminate(rr->sc, &error))
+ return error;
+
+ error = xfarray_load(rr->refcount_records, cur, &irec);
+ if (error)
+ return error;
+
+ if (dom == XFS_REFC_DOMAIN_SHARED &&
+ irec.rc_domain == XFS_REFC_DOMAIN_COW) {
+ dom = irec.rc_domain;
+ next_agbno = 0;
+ }
+
+ if (dom != irec.rc_domain)
+ return -EFSCORRUPTED;
+ if (irec.rc_startblock < next_agbno)
+ return -EFSCORRUPTED;
+
+ next_agbno = irec.rc_startblock + irec.rc_blockcount;
+ }
+
+ return error;
+}
+
+#define RRM_NEXT(r) ((r).startblock + (r).blockcount)
+/*
+ * Find the next block where the refcount changes, given the next rmap we
+ * looked at and the ones we're already tracking.
+ */
+static inline int
+xrep_refc_next_edge(
+ struct xfarray *rmap_bag,
+ struct xrep_refc_rmap *next_rrm,
+ bool next_valid,
+ xfs_agblock_t *nbnop)
+{
+ struct xrep_refc_rmap rrm;
+ xfarray_idx_t array_cur = XFARRAY_CURSOR_INIT;
+ xfs_agblock_t nbno = NULLAGBLOCK;
+ int error;
+
+ if (next_valid)
+ nbno = next_rrm->startblock;
+
+ while ((error = xfarray_iter(rmap_bag, &array_cur, &rrm)) == 1)
+ nbno = min_t(xfs_agblock_t, nbno, RRM_NEXT(rrm));
+
+ if (error)
+ return error;
+
+ /*
+ * We should have found /something/ because either next_rrm is the next
+ * interesting rmap to look at after emitting this refcount extent, or
+ * there are other rmaps in rmap_bag contributing to the current
+ * sharing count. But if something is seriously wrong, bail out.
+ */
+ if (nbno == NULLAGBLOCK)
+ return -EFSCORRUPTED;
+
+ *nbnop = nbno;
+ return 0;
+}
+
+/*
+ * Walk forward through the rmap btree to collect all rmaps starting at
+ * @bno in @rmap_bag. These represent the file(s) that share ownership of
+ * the current block. Upon return, the rmap cursor points to the last record
+ * satisfying the startblock constraint.
+ */
+static int
+xrep_refc_push_rmaps_at(
+ struct xrep_refc *rr,
+ struct xfarray *rmap_bag,
+ xfs_agblock_t bno,
+ struct xrep_refc_rmap *rrm,
+ bool *have,
+ uint64_t *stack_sz)
+{
+ struct xfs_scrub *sc = rr->sc;
+ int have_gt;
+ int error;
+
+ while (*have && rrm->startblock == bno) {
+ error = xfarray_store_anywhere(rmap_bag, rrm);
+ if (error)
+ return error;
+ (*stack_sz)++;
+ error = xrep_refc_walk_rmaps(rr, rrm, have);
+ if (error)
+ return error;
+ }
+
+ error = xfs_btree_decrement(sc->sa.rmap_cur, 0, &have_gt);
+ if (error)
+ return error;
+ if (XFS_IS_CORRUPT(sc->mp, !have_gt))
+ return -EFSCORRUPTED;
+
+ return 0;
+}
+
+/* Iterate all the rmap records to generate reference count data. */
+STATIC int
+xrep_refc_find_refcounts(
+ struct xrep_refc *rr)
+{
+ struct xrep_refc_rmap rrm;
+ struct xfs_scrub *sc = rr->sc;
+ struct xfarray *rmap_bag;
+ char *descr;
+ uint64_t old_stack_sz;
+ uint64_t stack_sz = 0;
+ xfs_agblock_t sbno;
+ xfs_agblock_t cbno;
+ xfs_agblock_t nbno;
+ bool have;
+ int error;
+
+ xrep_ag_btcur_init(sc, &sc->sa);
+
+ /*
+ * Set up a sparse array to store all the rmap records that we're
+ * tracking to generate a reference count record. If this exceeds
+ * MAXREFCOUNT, we clamp rc_refcount.
+ */
+ descr = xchk_xfile_ag_descr(sc, "rmap record bag");
+ error = xfarray_create(descr, 0, sizeof(struct xrep_refc_rmap),
+ &rmap_bag);
+ kfree(descr);
+ if (error)
+ goto out_cur;
+
+ /* Start the rmapbt cursor to the left of all records. */
+ error = xfs_btree_goto_left_edge(sc->sa.rmap_cur);
+ if (error)
+ goto out_bag;
+
+ /* Process reverse mappings into refcount data. */
+ while (xfs_btree_has_more_records(sc->sa.rmap_cur)) {
+ /* Push all rmaps with pblk == sbno onto the stack */
+ error = xrep_refc_walk_rmaps(rr, &rrm, &have);
+ if (error)
+ goto out_bag;
+ if (!have)
+ break;
+ sbno = cbno = rrm.startblock;
+ error = xrep_refc_push_rmaps_at(rr, rmap_bag, sbno,
+ &rrm, &have, &stack_sz);
+ if (error)
+ goto out_bag;
+
+ /* Set nbno to the bno of the next refcount change */
+ error = xrep_refc_next_edge(rmap_bag, &rrm, have, &nbno);
+ if (error)
+ goto out_bag;
+
+ ASSERT(nbno > sbno);
+ old_stack_sz = stack_sz;
+
+ /* While stack isn't empty... */
+ while (stack_sz) {
+ xfarray_idx_t array_cur = XFARRAY_CURSOR_INIT;
+
+ /* Pop all rmaps that end at nbno */
+ while ((error = xfarray_iter(rmap_bag, &array_cur,
+ &rrm)) == 1) {
+ if (RRM_NEXT(rrm) != nbno)
+ continue;
+ error = xfarray_unset(rmap_bag, array_cur - 1);
+ if (error)
+ goto out_bag;
+ stack_sz--;
+ }
+ if (error)
+ goto out_bag;
+
+ /* Push array items that start at nbno */
+ error = xrep_refc_walk_rmaps(rr, &rrm, &have);
+ if (error)
+ goto out_bag;
+ if (have) {
+ error = xrep_refc_push_rmaps_at(rr, rmap_bag,
+ nbno, &rrm, &have, &stack_sz);
+ if (error)
+ goto out_bag;
+ }
+
+ /* Emit refcount if necessary */
+ ASSERT(nbno > cbno);
+ if (stack_sz != old_stack_sz) {
+ if (old_stack_sz > 1) {
+ error = xrep_refc_stash(rr,
+ XFS_REFC_DOMAIN_SHARED,
+ cbno, nbno - cbno,
+ old_stack_sz);
+ if (error)
+ goto out_bag;
+ }
+ cbno = nbno;
+ }
+
+ /* Stack empty, go find the next rmap */
+ if (stack_sz == 0)
+ break;
+ old_stack_sz = stack_sz;
+ sbno = nbno;
+
+ /* Set nbno to the bno of the next refcount change */
+ error = xrep_refc_next_edge(rmap_bag, &rrm, have,
+ &nbno);
+ if (error)
+ goto out_bag;
+
+ ASSERT(nbno > sbno);
+ }
+ }
+
+ ASSERT(stack_sz == 0);
+out_bag:
+ xfarray_destroy(rmap_bag);
+out_cur:
+ xchk_ag_btcur_free(&sc->sa);
+ return error;
+}
+#undef RRM_NEXT
+
+/* Retrieve refcountbt data for bulk load. */
+STATIC int
+xrep_refc_get_records(
+ struct xfs_btree_cur *cur,
+ unsigned int idx,
+ struct xfs_btree_block *block,
+ unsigned int nr_wanted,
+ void *priv)
+{
+ struct xfs_refcount_irec *irec = &cur->bc_rec.rc;
+ struct xrep_refc *rr = priv;
+ union xfs_btree_rec *block_rec;
+ unsigned int loaded;
+ int error;
+
+ for (loaded = 0; loaded < nr_wanted; loaded++, idx++) {
+ error = xfarray_load(rr->refcount_records, rr->array_cur++,
+ irec);
+ if (error)
+ return error;
+
+ block_rec = xfs_btree_rec_addr(cur, idx, block);
+ cur->bc_ops->init_rec_from_cur(cur, block_rec);
+ }
+
+ return loaded;
+}
+
+/* Feed one of the new btree blocks to the bulk loader. */
+STATIC int
+xrep_refc_claim_block(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *ptr,
+ void *priv)
+{
+ struct xrep_refc *rr = priv;
+ int error;
+
+ error = xrep_newbt_relog_autoreap(&rr->new_btree);
+ if (error)
+ return error;
+
+ return xrep_newbt_claim_block(cur, &rr->new_btree, ptr);
+}
+
+/* Update the AGF counters. */
+STATIC int
+xrep_refc_reset_counters(
+ struct xrep_refc *rr)
+{
+ struct xfs_scrub *sc = rr->sc;
+ struct xfs_perag *pag = sc->sa.pag;
+
+ /*
+ * After we commit the new btree to disk, it is possible that the
+ * process to reap the old btree blocks will race with the AIL trying
+ * to checkpoint the old btree blocks into the filesystem. If the new
+ * tree is shorter than the old one, the refcountbt write verifier will
+ * fail and the AIL will shut down the filesystem.
+ *
+ * To avoid this, save the old incore btree height values as the alt
+ * height values before re-initializing the perag info from the updated
+ * AGF to capture all the new values.
+ */
+ pag->pagf_alt_refcount_level = pag->pagf_refcount_level;
+
+ /* Reinitialize with the values we just logged. */
+ return xrep_reinit_pagf(sc);
+}
+
+/*
+ * Use the collected refcount information to stage a new refcount btree. If
+ * this is successful we'll return with the new btree root information logged
+ * to the repair transaction but not yet committed.
+ */
+STATIC int
+xrep_refc_build_new_tree(
+ struct xrep_refc *rr)
+{
+ struct xfs_scrub *sc = rr->sc;
+ struct xfs_btree_cur *refc_cur;
+ struct xfs_perag *pag = sc->sa.pag;
+ xfs_fsblock_t fsbno;
+ int error;
+
+ error = xrep_refc_sort_records(rr);
+ if (error)
+ return error;
+
+ /*
+ * Prepare to construct the new btree by reserving disk space for the
+ * new btree and setting up all the accounting information we'll need
+ * to root the new btree while it's under construction and before we
+ * attach it to the AG header.
+ */
+ fsbno = XFS_AGB_TO_FSB(sc->mp, pag->pag_agno, xfs_refc_block(sc->mp));
+ xrep_newbt_init_ag(&rr->new_btree, sc, &XFS_RMAP_OINFO_REFC, fsbno,
+ XFS_AG_RESV_METADATA);
+ rr->new_btree.bload.get_records = xrep_refc_get_records;
+ rr->new_btree.bload.claim_block = xrep_refc_claim_block;
+
+ /* Compute how many blocks we'll need. */
+ refc_cur = xfs_refcountbt_stage_cursor(sc->mp, &rr->new_btree.afake,
+ pag);
+ error = xfs_btree_bload_compute_geometry(refc_cur,
+ &rr->new_btree.bload,
+ xfarray_length(rr->refcount_records));
+ if (error)
+ goto err_cur;
+
+ /* Last chance to abort before we start committing fixes. */
+ if (xchk_should_terminate(sc, &error))
+ goto err_cur;
+
+ /* Reserve the space we'll need for the new btree. */
+ error = xrep_newbt_alloc_blocks(&rr->new_btree,
+ rr->new_btree.bload.nr_blocks);
+ if (error)
+ goto err_cur;
+
+ /*
+ * Due to btree slack factors, it's possible for a new btree to be one
+ * level taller than the old btree. Update the incore btree height so
+ * that we don't trip the verifiers when writing the new btree blocks
+ * to disk.
+ */
+ pag->pagf_alt_refcount_level = rr->new_btree.bload.btree_height;
+
+ /* Add all observed refcount records. */
+ rr->array_cur = XFARRAY_CURSOR_INIT;
+ error = xfs_btree_bload(refc_cur, &rr->new_btree.bload, rr);
+ if (error)
+ goto err_level;
+
+ /*
+ * Install the new btree in the AG header. After this point the old
+ * btree is no longer accessible and the new tree is live.
+ */
+ xfs_refcountbt_commit_staged_btree(refc_cur, sc->tp, sc->sa.agf_bp);
+ xfs_btree_del_cursor(refc_cur, 0);
+
+ /* Reset the AGF counters now that we've changed the btree shape. */
+ error = xrep_refc_reset_counters(rr);
+ if (error)
+ goto err_newbt;
+
+ /* Dispose of any unused blocks and the accounting information. */
+ error = xrep_newbt_commit(&rr->new_btree);
+ if (error)
+ return error;
+
+ return xrep_roll_ag_trans(sc);
+
+err_level:
+ pag->pagf_alt_refcount_level = 0;
+err_cur:
+ xfs_btree_del_cursor(refc_cur, error);
+err_newbt:
+ xrep_newbt_cancel(&rr->new_btree);
+ return error;
+}
+
+/*
+ * Now that we've logged the roots of the new btrees, invalidate all of the
+ * old blocks and free them.
+ */
+STATIC int
+xrep_refc_remove_old_tree(
+ struct xrep_refc *rr)
+{
+ struct xfs_scrub *sc = rr->sc;
+ struct xfs_perag *pag = sc->sa.pag;
+ int error;
+
+ /* Free the old refcountbt blocks if they're not in use. */
+ error = xrep_reap_agblocks(sc, &rr->old_refcountbt_blocks,
+ &XFS_RMAP_OINFO_REFC, XFS_AG_RESV_METADATA);
+ if (error)
+ return error;
+
+ /*
+ * Now that we've zapped all the old refcountbt blocks we can turn off
+ * the alternate height mechanism and reset the per-AG space
+ * reservations.
+ */
+ pag->pagf_alt_refcount_level = 0;
+ sc->flags |= XREP_RESET_PERAG_RESV;
+ return 0;
+}
+
+/* Rebuild the refcount btree. */
+int
+xrep_refcountbt(
+ struct xfs_scrub *sc)
+{
+ struct xrep_refc *rr;
+ struct xfs_mount *mp = sc->mp;
+ char *descr;
+ int error;
+
+ /* We require the rmapbt to rebuild anything. */
+ if (!xfs_has_rmapbt(mp))
+ return -EOPNOTSUPP;
+
+ rr = kzalloc(sizeof(struct xrep_refc), XCHK_GFP_FLAGS);
+ if (!rr)
+ return -ENOMEM;
+ rr->sc = sc;
+
+ /* Set up enough storage to handle one refcount record per block. */
+ descr = xchk_xfile_ag_descr(sc, "reference count records");
+ error = xfarray_create(descr, mp->m_sb.sb_agblocks,
+ sizeof(struct xfs_refcount_irec),
+ &rr->refcount_records);
+ kfree(descr);
+ if (error)
+ goto out_rr;
+
+ /* Collect all reference counts. */
+ xagb_bitmap_init(&rr->old_refcountbt_blocks);
+ error = xrep_refc_find_refcounts(rr);
+ if (error)
+ goto out_bitmap;
+
+ /* Rebuild the refcount information. */
+ error = xrep_refc_build_new_tree(rr);
+ if (error)
+ goto out_bitmap;
+
+ /* Kill the old tree. */
+ error = xrep_refc_remove_old_tree(rr);
+
+out_bitmap:
+ xagb_bitmap_destroy(&rr->old_refcountbt_blocks);
+ xfarray_destroy(rr->refcount_records);
+out_rr:
+ kfree(rr);
+ return error;
+}
diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
index 3ff5e37316685..42325305d29d9 100644
--- a/fs/xfs/scrub/repair.h
+++ b/fs/xfs/scrub/repair.h
@@ -73,6 +73,7 @@ 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_refcountbt(struct xfs_scrub *sc);

int xrep_reinit_pagf(struct xfs_scrub *sc);
int xrep_reinit_pagi(struct xfs_scrub *sc);
@@ -126,6 +127,7 @@ xrep_setup_nothing(
#define xrep_agi xrep_notsupported
#define xrep_allocbt xrep_notsupported
#define xrep_iallocbt xrep_notsupported
+#define xrep_refcountbt xrep_notsupported

#endif /* CONFIG_XFS_ONLINE_REPAIR */

diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 57f2db883792e..71aee7e3dd43a 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -276,7 +276,7 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
.setup = xchk_setup_ag_refcountbt,
.scrub = xchk_refcountbt,
.has = xfs_has_reflink,
- .repair = xrep_notsupported,
+ .repair = xrep_refcountbt,
},
[XFS_SCRUB_TYPE_INODE] = { /* inode record */
.type = ST_INODE,
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 79d1316b288ed..358c7ddbf14e2 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -1205,27 +1205,29 @@ TRACE_EVENT(xrep_ibt_found,
__entry->freemask)
)

-TRACE_EVENT(xrep_refcount_extent_fn,
- TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno,
- struct xfs_refcount_irec *irec),
- TP_ARGS(mp, agno, irec),
+TRACE_EVENT(xrep_refc_found,
+ TP_PROTO(struct xfs_perag *pag, const struct xfs_refcount_irec *rec),
+ TP_ARGS(pag, rec),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(xfs_agnumber_t, agno)
+ __field(enum xfs_refc_domain, domain)
__field(xfs_agblock_t, startblock)
__field(xfs_extlen_t, blockcount)
__field(xfs_nlink_t, refcount)
),
TP_fast_assign(
- __entry->dev = mp->m_super->s_dev;
- __entry->agno = agno;
- __entry->startblock = irec->rc_startblock;
- __entry->blockcount = irec->rc_blockcount;
- __entry->refcount = irec->rc_refcount;
+ __entry->dev = pag->pag_mount->m_super->s_dev;
+ __entry->agno = pag->pag_agno;
+ __entry->domain = rec->rc_domain;
+ __entry->startblock = rec->rc_startblock;
+ __entry->blockcount = rec->rc_blockcount;
+ __entry->refcount = rec->rc_refcount;
),
- TP_printk("dev %d:%d agno 0x%x agbno 0x%x fsbcount 0x%x refcount %u",
+ TP_printk("dev %d:%d agno 0x%x dom %s agbno 0x%x fsbcount 0x%x refcount %u",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->agno,
+ __print_symbolic(__entry->domain, XFS_REFC_DOMAIN_STRINGS),
__entry->startblock,
__entry->blockcount,
__entry->refcount)