From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reconstruct the refcount data from the rmap btree.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/Makefile | 1
fs/xfs/scrub/refcount_repair.c | 586 ++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/repair.h | 2
fs/xfs/scrub/scrub.c | 2
4 files changed, 590 insertions(+), 1 deletion(-)
create mode 100644 fs/xfs/scrub/refcount_repair.c
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index af1dc9aeb1a7..4ca97e026f94 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -167,6 +167,7 @@ xfs-y += $(addprefix scrub/, \
alloc_repair.o \
bitmap.o \
ialloc_repair.o \
+ refcount_repair.o \
repair.o \
)
endif
diff --git a/fs/xfs/scrub/refcount_repair.c b/fs/xfs/scrub/refcount_repair.c
new file mode 100644
index 000000000000..549e1adc972c
--- /dev/null
+++ b/fs/xfs/scrub/refcount_repair.c
@@ -0,0 +1,586 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ */
+#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_itable.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 "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"
+
+/*
+ * 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.
+ */
+
+struct xrep_refc_rmap {
+ struct list_head list;
+ struct xfs_rmap_irec rmap;
+};
+
+struct xrep_refc_extent {
+ struct list_head list;
+ struct xfs_refcount_irec refc;
+};
+
+struct xrep_refc {
+ struct list_head rmap_bag; /* rmaps we're tracking */
+ struct list_head rmap_idle; /* idle rmaps */
+ struct list_head *extlist; /* refcount extents */
+ struct xfs_bitmap *btlist; /* old refcountbt blocks */
+ struct xfs_scrub *sc;
+ unsigned long nr_records;/* nr refcount extents */
+ xfs_extlen_t btblocks; /* # of refcountbt blocks */
+};
+
+/* Grab the next record from the rmapbt. */
+STATIC int
+xrep_refc_next_rmap(
+ struct xfs_btree_cur *cur,
+ struct xrep_refc *rr,
+ struct xfs_rmap_irec *rec,
+ bool *have_rec)
+{
+ struct xfs_rmap_irec rmap;
+ struct xfs_mount *mp = cur->bc_mp;
+ struct xrep_refc_extent *rre;
+ xfs_fsblock_t fsbno;
+ 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))
+ goto out_error;
+
+ error = xfs_btree_increment(cur, 0, &have_gt);
+ if (error)
+ goto out_error;
+ if (!have_gt)
+ return 0;
+
+ error = xfs_rmap_get_rec(cur, &rmap, &have_gt);
+ if (error)
+ goto out_error;
+ XFS_WANT_CORRUPTED_GOTO(mp, have_gt == 1, out_error);
+
+ if (rmap.rm_owner == XFS_RMAP_OWN_COW) {
+ /* Pass CoW staging extents right through. */
+ rre = kmem_alloc(sizeof(struct xrep_refc_extent),
+ KM_MAYFAIL);
+ if (!rre)
+ goto out_error;
+
+ INIT_LIST_HEAD(&rre->list);
+ rre->refc.rc_startblock = rmap.rm_startblock +
+ XFS_REFC_COW_START;
+ rre->refc.rc_blockcount = rmap.rm_blockcount;
+ rre->refc.rc_refcount = 1;
+ list_add_tail(&rre->list, rr->extlist);
+ } else if (rmap.rm_owner == XFS_RMAP_OWN_REFC) {
+ /* refcountbt block, dump it when we're done. */
+ rr->btblocks += rmap.rm_blockcount;
+ fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
+ cur->bc_private.a.agno,
+ rmap.rm_startblock);
+ error = xfs_bitmap_set(rr->btlist, fsbno,
+ rmap.rm_blockcount);
+ if (error)
+ goto out_error;
+ }
+ } while (XFS_RMAP_NON_INODE_OWNER(rmap.rm_owner) ||
+ xfs_internal_inum(mp, rmap.rm_owner) ||
+ (rmap.rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK |
+ XFS_RMAP_UNWRITTEN)));
+
+ *rec = rmap;
+ *have_rec = true;
+ return 0;
+
+out_error:
+ return error;
+}
+
+/* Recycle an idle rmap or allocate a new one. */
+static struct xrep_refc_rmap *
+xrep_refc_get_rmap(
+ struct xrep_refc *rr)
+{
+ struct xrep_refc_rmap *rrm;
+
+ if (list_empty(&rr->rmap_idle)) {
+ rrm = kmem_alloc(sizeof(struct xrep_refc_rmap), KM_MAYFAIL);
+ if (!rrm)
+ return NULL;
+ INIT_LIST_HEAD(&rrm->list);
+ return rrm;
+ }
+
+ rrm = list_first_entry(&rr->rmap_idle, struct xrep_refc_rmap, list);
+ list_del_init(&rrm->list);
+ return rrm;
+}
+
+/* Compare two btree extents. */
+static int
+xrep_refcount_extent_cmp(
+ void *priv,
+ struct list_head *a,
+ struct list_head *b)
+{
+ struct xrep_refc_extent *ap;
+ struct xrep_refc_extent *bp;
+
+ ap = container_of(a, struct xrep_refc_extent, list);
+ bp = container_of(b, struct xrep_refc_extent, list);
+
+ if (ap->refc.rc_startblock > bp->refc.rc_startblock)
+ return 1;
+ else if (ap->refc.rc_startblock < bp->refc.rc_startblock)
+ return -1;
+ return 0;
+}
+
+/* Record a reference count extent. */
+STATIC int
+xrep_refc_new_refc(
+ struct xfs_scrub *sc,
+ struct xrep_refc *rr,
+ xfs_agblock_t agbno,
+ xfs_extlen_t len,
+ xfs_nlink_t refcount)
+{
+ struct xrep_refc_extent *rre;
+ struct xfs_refcount_irec irec;
+
+ irec.rc_startblock = agbno;
+ irec.rc_blockcount = len;
+ irec.rc_refcount = refcount;
+
+ trace_xrep_refcount_extent_fn(sc->mp, sc->sa.agno, &irec);
+
+ rre = kmem_alloc(sizeof(struct xrep_refc_extent), KM_MAYFAIL);
+ if (!rre)
+ return -ENOMEM;
+ INIT_LIST_HEAD(&rre->list);
+ rre->refc = irec;
+ list_add_tail(&rre->list, rr->extlist);
+
+ return 0;
+}
+
+/* Iterate all the rmap records to generate reference count data. */
+#define RMAP_NEXT(r) ((r).rm_startblock + (r).rm_blockcount)
+STATIC int
+xrep_refc_generate_refcounts(
+ struct xfs_scrub *sc,
+ struct xrep_refc *rr)
+{
+ struct xfs_rmap_irec rmap;
+ struct xfs_btree_cur *cur;
+ struct xrep_refc_rmap *rrm;
+ struct xrep_refc_rmap *n;
+ xfs_agblock_t sbno;
+ xfs_agblock_t cbno;
+ xfs_agblock_t nbno;
+ size_t old_stack_sz;
+ size_t stack_sz = 0;
+ bool have;
+ int have_gt;
+ int error;
+
+ /* Start the rmapbt cursor to the left of all records. */
+ cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, sc->sa.agf_bp,
+ sc->sa.agno);
+ error = xfs_rmap_lookup_le(cur, 0, 0, 0, 0, 0, &have_gt);
+ if (error)
+ goto out;
+ ASSERT(have_gt == 0);
+
+ /* Process reverse mappings into refcount data. */
+ while (xfs_btree_has_more_records(cur)) {
+ /* Push all rmaps with pblk == sbno onto the stack */
+ error = xrep_refc_next_rmap(cur, rr, &rmap, &have);
+ if (error)
+ goto out;
+ if (!have)
+ break;
+ sbno = cbno = rmap.rm_startblock;
+ while (have && rmap.rm_startblock == sbno) {
+ rrm = xrep_refc_get_rmap(rr);
+ if (!rrm)
+ goto out;
+ rrm->rmap = rmap;
+ list_add_tail(&rrm->list, &rr->rmap_bag);
+ stack_sz++;
+ error = xrep_refc_next_rmap(cur, rr, &rmap, &have);
+ if (error)
+ goto out;
+ }
+ error = xfs_btree_decrement(cur, 0, &have_gt);
+ if (error)
+ goto out;
+ XFS_WANT_CORRUPTED_GOTO(sc->mp, have_gt, out);
+
+ /* Set nbno to the bno of the next refcount change */
+ nbno = have ? rmap.rm_startblock : NULLAGBLOCK;
+ list_for_each_entry(rrm, &rr->rmap_bag, list)
+ nbno = min_t(xfs_agblock_t, nbno, RMAP_NEXT(rrm->rmap));
+
+ ASSERT(nbno > sbno);
+ old_stack_sz = stack_sz;
+
+ /* While stack isn't empty... */
+ while (stack_sz) {
+ /* Pop all rmaps that end at nbno */
+ list_for_each_entry_safe(rrm, n, &rr->rmap_bag, list) {
+ if (RMAP_NEXT(rrm->rmap) != nbno)
+ continue;
+ stack_sz--;
+ list_move(&rrm->list, &rr->rmap_idle);
+ }
+
+ /* Push array items that start at nbno */
+ error = xrep_refc_next_rmap(cur, rr, &rmap, &have);
+ if (error)
+ goto out;
+ while (have && rmap.rm_startblock == nbno) {
+ rrm = xrep_refc_get_rmap(rr);
+ if (!rrm)
+ goto out;
+ rrm->rmap = rmap;
+ list_add_tail(&rrm->list, &rr->rmap_bag);
+ stack_sz++;
+ error = xrep_refc_next_rmap(cur, rr, &rmap,
+ &have);
+ if (error)
+ goto out;
+ }
+ error = xfs_btree_decrement(cur, 0, &have_gt);
+ if (error)
+ goto out;
+ XFS_WANT_CORRUPTED_GOTO(sc->mp, have_gt, out);
+
+ /* Emit refcount if necessary */
+ ASSERT(nbno > cbno);
+ if (stack_sz != old_stack_sz) {
+ if (old_stack_sz > 1) {
+ error = xrep_refc_new_refc(sc, rr, cbno,
+ nbno - cbno,
+ old_stack_sz);
+ if (error)
+ goto out;
+ rr->nr_records++;
+ }
+ 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 */
+ nbno = have ? rmap.rm_startblock : NULLAGBLOCK;
+ list_for_each_entry(rrm, &rr->rmap_bag, list)
+ nbno = min_t(xfs_agblock_t, nbno,
+ RMAP_NEXT(rrm->rmap));
+
+ ASSERT(nbno > sbno);
+ }
+ }
+
+ /* Free all the leftover rmap records. */
+ list_for_each_entry_safe(rrm, n, &rr->rmap_idle, list) {
+ list_del(&rrm->list);
+ kmem_free(rrm);
+ }
+
+ ASSERT(list_empty(&rr->rmap_bag));
+out:
+ xfs_btree_del_cursor(cur, error);
+ return error;
+}
+#undef RMAP_NEXT
+
+/*
+ * Generate all the reference counts for this AG and a list of the old
+ * refcount btree blocks. Figure out if we have enough free space to
+ * reconstruct the inode btrees. The caller must clean up the lists if
+ * anything goes wrong.
+ */
+STATIC int
+xrep_refc_find_refcounts(
+ struct xfs_scrub *sc,
+ struct list_head *refcount_records,
+ struct xfs_bitmap *old_refcountbt_blocks)
+{
+ struct xrep_refc rr;
+ struct xrep_refc_rmap *rrm;
+ struct xrep_refc_rmap *n;
+ struct xfs_mount *mp = sc->mp;
+ int error;
+
+ INIT_LIST_HEAD(&rr.rmap_bag);
+ INIT_LIST_HEAD(&rr.rmap_idle);
+ rr.extlist = refcount_records;
+ rr.btlist = old_refcountbt_blocks;
+ rr.btblocks = 0;
+ rr.sc = sc;
+ rr.nr_records = 0;
+
+ /* Generate all the refcount records. */
+ error = xrep_refc_generate_refcounts(sc, &rr);
+ if (error)
+ goto out;
+
+ /* Do we actually have enough space to do this? */
+ if (!xrep_ag_has_space(sc->sa.pag,
+ xfs_refcountbt_calc_size(mp, rr.nr_records),
+ XFS_AG_RESV_METADATA)) {
+ error = -ENOSPC;
+ goto out;
+ }
+
+out:
+ list_for_each_entry_safe(rrm, n, &rr.rmap_idle, list) {
+ list_del(&rrm->list);
+ kmem_free(rrm);
+ }
+ list_for_each_entry_safe(rrm, n, &rr.rmap_bag, list) {
+ list_del(&rrm->list);
+ kmem_free(rrm);
+ }
+ return error;
+}
+
+/* Initialize new refcountbt root and implant it into the AGF. */
+STATIC int
+xrep_refc_reset_btree(
+ struct xfs_scrub *sc,
+ struct xfs_owner_info *oinfo,
+ int *log_flags)
+{
+ struct xfs_buf *bp;
+ struct xfs_agf *agf;
+ xfs_fsblock_t btfsb;
+ int error;
+
+ agf = XFS_BUF_TO_AGF(sc->sa.agf_bp);
+
+ /* Initialize a new refcountbt root. */
+ error = xrep_alloc_ag_block(sc, oinfo, &btfsb, XFS_AG_RESV_METADATA);
+ if (error)
+ return error;
+ error = xrep_init_btblock(sc, btfsb, &bp, XFS_BTNUM_REFC,
+ &xfs_refcountbt_buf_ops);
+ if (error)
+ return error;
+ agf->agf_refcount_root = cpu_to_be32(XFS_FSB_TO_AGBNO(sc->mp, btfsb));
+ agf->agf_refcount_level = cpu_to_be32(1);
+ agf->agf_refcount_blocks = cpu_to_be32(1);
+ *log_flags |= XFS_AGF_REFCOUNT_BLOCKS | XFS_AGF_REFCOUNT_ROOT |
+ XFS_AGF_REFCOUNT_LEVEL;
+
+ return 0;
+}
+
+/* Build new refcount btree and dispose of the old one. */
+STATIC int
+xrep_refc_rebuild_tree(
+ struct xfs_scrub *sc,
+ struct list_head *refcount_records,
+ struct xfs_owner_info *oinfo,
+ struct xfs_bitmap *old_refcountbt_blocks)
+{
+ struct xrep_refc_extent *rre;
+ struct xrep_refc_extent *n;
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_btree_cur *cur;
+ int have_gt;
+ int error;
+
+ /* Add all records. */
+ list_sort(NULL, refcount_records, xrep_refcount_extent_cmp);
+ list_for_each_entry_safe(rre, n, refcount_records, list) {
+ /* Insert into the refcountbt. */
+ cur = xfs_refcountbt_init_cursor(mp, sc->tp, sc->sa.agf_bp,
+ sc->sa.agno, NULL);
+ error = xfs_refcount_lookup_eq(cur, rre->refc.rc_startblock,
+ &have_gt);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(mp, have_gt == 0);
+ error = xfs_refcount_insert(cur, &rre->refc, &have_gt);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(mp, have_gt == 1);
+ xfs_btree_del_cursor(cur, error);
+ cur = NULL;
+
+ error = xrep_roll_ag_trans(sc);
+ if (error)
+ return error;
+
+ list_del(&rre->list);
+ kmem_free(rre);
+ }
+
+ /* Free the old refcountbt blocks if they're not in use. */
+ return xrep_reap_extents(sc, old_refcountbt_blocks, oinfo,
+ XFS_AG_RESV_METADATA);
+}
+
+/* Free every record in the refcount list. */
+STATIC void
+xrep_refc_cancel_recs(
+ struct list_head *recs)
+{
+ struct xrep_refc_extent *rre;
+ struct xrep_refc_extent *n;
+
+ list_for_each_entry_safe(rre, n, recs, list) {
+ list_del(&rre->list);
+ kmem_free(rre);
+ }
+}
+
+/* Rebuild the refcount btree. */
+int
+xrep_refcountbt(
+ struct xfs_scrub *sc)
+{
+ struct xfs_owner_info oinfo;
+ struct list_head refcount_records;
+ struct xfs_bitmap old_refcountbt_blocks;
+ struct xfs_mount *mp = sc->mp;
+ int log_flags = 0;
+ int error;
+
+ /* We require the rmapbt to rebuild anything. */
+ if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
+ return -EOPNOTSUPP;
+
+ xchk_perag_get(sc->mp, &sc->sa);
+
+ /* Collect all reference counts. */
+ xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_REFC);
+ INIT_LIST_HEAD(&refcount_records);
+ xfs_bitmap_init(&old_refcountbt_blocks);
+ error = xrep_refc_find_refcounts(sc, &refcount_records,
+ &old_refcountbt_blocks);
+ if (error)
+ goto out;
+
+ /*
+ * Blow out the old refcount btrees. This is the point at which
+ * we are no longer able to bail out gracefully.
+ */
+ error = xrep_refc_reset_btree(sc, &oinfo, &log_flags);
+ if (error)
+ goto out;
+ xfs_alloc_log_agf(sc->tp, sc->sa.agf_bp, log_flags);
+
+ /* Invalidate all the inobt/finobt blocks in btlist. */
+ error = xrep_invalidate_blocks(sc, &old_refcountbt_blocks);
+ if (error)
+ goto out;
+ error = xrep_roll_ag_trans(sc);
+ if (error)
+ goto out;
+
+ /* Now rebuild the refcount information. */
+ error = xrep_refc_rebuild_tree(sc, &refcount_records, &oinfo,
+ &old_refcountbt_blocks);
+ if (error)
+ goto out;
+ sc->reset_perag_resv = true;
+out:
+ xfs_bitmap_destroy(&old_refcountbt_blocks);
+ xrep_refc_cancel_recs(&refcount_records);
+ return error;
+}
diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
index 0cc53dee3228..da12c20376ae 100644
--- a/fs/xfs/scrub/repair.h
+++ b/fs/xfs/scrub/repair.h
@@ -64,6 +64,7 @@ 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);
#else
@@ -100,6 +101,7 @@ xrep_reset_perag_resv(
#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 631b0b06db99..843eafe0acef 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -265,7 +265,7 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
.setup = xchk_setup_ag_refcountbt,
.scrub = xchk_refcountbt,
.has = xfs_sb_version_hasreflink,
- .repair = xrep_notsupported,
+ .repair = xrep_refcountbt,
},
[XFS_SCRUB_TYPE_INODE] = { /* inode record */
.type = ST_INODE,
--
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