[PATCH 33/37] xfs: create a shadow rmap btree during realtime rmap repair

Darrick J. Wong
2024-12-13T01:09:13Z

From: Darrick J. Wong <djwong@kernel.org>

Create an in-memory btree of rmap records instead of an array. This
enables us to do live record collection instead of freezing the fs.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_btree_mem.c | 1
fs/xfs/libxfs/xfs_rmap.c | 3 +
fs/xfs/libxfs/xfs_rtrmap_btree.c | 117 ++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_rtrmap_btree.h | 6 ++
fs/xfs/libxfs/xfs_shared.h | 7 ++
fs/xfs/scrub/rtrmap_repair.c | 137 ++++++++++++++++++++++++++------------
fs/xfs/xfs_stats.c | 3 +
fs/xfs/xfs_stats.h | 1
8 files changed, 228 insertions(+), 47 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_btree_mem.c b/fs/xfs/libxfs/xfs_btree_mem.c
index df3d613675a15a..f2f7b4305413e9 100644
--- a/fs/xfs/libxfs/xfs_btree_mem.c
+++ b/fs/xfs/libxfs/xfs_btree_mem.c
@@ -18,6 +18,7 @@
#include "xfs_ag.h"
#include "xfs_buf_item.h"
#include "xfs_trace.h"
+#include "xfs_rtgroup.h"

/* Set the root of an in-memory btree. */
void
diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
index 2f0688a57991cc..f8415fd96cc2aa 100644
--- a/fs/xfs/libxfs/xfs_rmap.c
+++ b/fs/xfs/libxfs/xfs_rmap.c
@@ -327,7 +327,8 @@ xfs_rmap_check_btrec(
struct xfs_btree_cur *cur,
const struct xfs_rmap_irec *irec)
{
- if (xfs_btree_is_rtrmap(cur->bc_ops))
+ if (xfs_btree_is_rtrmap(cur->bc_ops) ||
+ xfs_btree_is_mem_rtrmap(cur->bc_ops))
return xfs_rtrmap_check_irec(to_rtg(cur->bc_group), irec);
return xfs_rmap_check_irec(to_perag(cur->bc_group), irec);
}
diff --git a/fs/xfs/libxfs/xfs_rtrmap_btree.c b/fs/xfs/libxfs/xfs_rtrmap_btree.c
index 571a9e1b956099..3cb8f126b9ce16 100644
--- a/fs/xfs/libxfs/xfs_rtrmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rtrmap_btree.c
@@ -28,6 +28,8 @@
#include "xfs_rtgroup.h"
#include "xfs_bmap.h"
#include "xfs_health.h"
+#include "xfs_buf_mem.h"
+#include "xfs_btree_mem.h"

static struct kmem_cache *xfs_rtrmapbt_cur_cache;

@@ -542,6 +544,121 @@ xfs_rtrmapbt_init_cursor(
return cur;
}

+#ifdef CONFIG_XFS_BTREE_IN_MEM
+/*
+ * Validate an in-memory realtime rmap btree block. Callers are allowed to
+ * generate an in-memory btree even if the ondisk feature is not enabled.
+ */
+static xfs_failaddr_t
+xfs_rtrmapbt_mem_verify(
+ struct xfs_buf *bp)
+{
+ struct xfs_mount *mp = bp->b_mount;
+ struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
+ xfs_failaddr_t fa;
+ unsigned int level;
+ unsigned int maxrecs;
+
+ if (!xfs_verify_magic(bp, block->bb_magic))
+ return __this_address;
+
+ fa = xfs_btree_fsblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
+ if (fa)
+ return fa;
+
+ level = be16_to_cpu(block->bb_level);
+ if (xfs_has_rmapbt(mp)) {
+ if (level >= mp->m_rtrmap_maxlevels)
+ return __this_address;
+ } else {
+ if (level >= xfs_rtrmapbt_maxlevels_ondisk())
+ return __this_address;
+ }
+
+ maxrecs = xfs_rtrmapbt_maxrecs(mp, XFBNO_BLOCKSIZE, level == 0);
+ return xfs_btree_memblock_verify(bp, maxrecs);
+}
+
+static void
+xfs_rtrmapbt_mem_rw_verify(
+ struct xfs_buf *bp)
+{
+ xfs_failaddr_t fa = xfs_rtrmapbt_mem_verify(bp);
+
+ if (fa)
+ xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+}
+
+/* skip crc checks on in-memory btrees to save time */
+static const struct xfs_buf_ops xfs_rtrmapbt_mem_buf_ops = {
+ .name = "xfs_rtrmapbt_mem",
+ .magic = { 0, cpu_to_be32(XFS_RTRMAP_CRC_MAGIC) },
+ .verify_read = xfs_rtrmapbt_mem_rw_verify,
+ .verify_write = xfs_rtrmapbt_mem_rw_verify,
+ .verify_struct = xfs_rtrmapbt_mem_verify,
+};
+
+const struct xfs_btree_ops xfs_rtrmapbt_mem_ops = {
+ .type = XFS_BTREE_TYPE_MEM,
+ .geom_flags = XFS_BTGEO_OVERLAPPING,
+
+ .rec_len = sizeof(struct xfs_rmap_rec),
+ /* Overlapping btree; 2 keys per pointer. */
+ .key_len = 2 * sizeof(struct xfs_rmap_key),
+ .ptr_len = XFS_BTREE_LONG_PTR_LEN,
+
+ .lru_refs = XFS_RMAP_BTREE_REF,
+ .statoff = XFS_STATS_CALC_INDEX(xs_rtrmap_mem_2),
+
+ .dup_cursor = xfbtree_dup_cursor,
+ .set_root = xfbtree_set_root,
+ .alloc_block = xfbtree_alloc_block,
+ .free_block = xfbtree_free_block,
+ .get_minrecs = xfbtree_get_minrecs,
+ .get_maxrecs = xfbtree_get_maxrecs,
+ .init_key_from_rec = xfs_rtrmapbt_init_key_from_rec,
+ .init_high_key_from_rec = xfs_rtrmapbt_init_high_key_from_rec,
+ .init_rec_from_cur = xfs_rtrmapbt_init_rec_from_cur,
+ .init_ptr_from_cur = xfbtree_init_ptr_from_cur,
+ .key_diff = xfs_rtrmapbt_key_diff,
+ .buf_ops = &xfs_rtrmapbt_mem_buf_ops,
+ .diff_two_keys = xfs_rtrmapbt_diff_two_keys,
+ .keys_inorder = xfs_rtrmapbt_keys_inorder,
+ .recs_inorder = xfs_rtrmapbt_recs_inorder,
+ .keys_contiguous = xfs_rtrmapbt_keys_contiguous,
+};
+
+/* Create a cursor for an in-memory btree. */
+struct xfs_btree_cur *
+xfs_rtrmapbt_mem_cursor(
+ struct xfs_rtgroup *rtg,
+ struct xfs_trans *tp,
+ struct xfbtree *xfbt)
+{
+ struct xfs_mount *mp = rtg_mount(rtg);
+ struct xfs_btree_cur *cur;
+
+ cur = xfs_btree_alloc_cursor(mp, tp, &xfs_rtrmapbt_mem_ops,
+ mp->m_rtrmap_maxlevels, xfs_rtrmapbt_cur_cache);
+ cur->bc_mem.xfbtree = xfbt;
+ cur->bc_nlevels = xfbt->nlevels;
+ cur->bc_group = xfs_group_hold(rtg_group(rtg));
+ return cur;
+}
+
+/* Create an in-memory realtime rmap btree. */
+int
+xfs_rtrmapbt_mem_init(
+ struct xfs_mount *mp,
+ struct xfbtree *xfbt,
+ struct xfs_buftarg *btp,
+ xfs_rgnumber_t rgno)
+{
+ xfbt->owner = rgno;
+ return xfbtree_init(mp, xfbt, btp, &xfs_rtrmapbt_mem_ops);
+}
+#endif /* CONFIG_XFS_BTREE_IN_MEM */
+
/*
* Install a new rt reverse mapping btree root. Caller is responsible for
* invalidating and freeing the old btree blocks.
diff --git a/fs/xfs/libxfs/xfs_rtrmap_btree.h b/fs/xfs/libxfs/xfs_rtrmap_btree.h
index 6e3dab8c44f7c2..6a2d432b55ad78 100644
--- a/fs/xfs/libxfs/xfs_rtrmap_btree.h
+++ b/fs/xfs/libxfs/xfs_rtrmap_btree.h
@@ -11,6 +11,7 @@ struct xfs_btree_cur;
struct xfs_mount;
struct xbtree_ifakeroot;
struct xfs_rtgroup;
+struct xfbtree;

/* rmaps only exist on crc enabled filesystems */
#define XFS_RTRMAP_BLOCK_LEN XFS_BTREE_LBLOCK_CRC_LEN
@@ -201,4 +202,9 @@ int xfs_rtrmapbt_init_rtsb(struct xfs_mount *mp, struct xfs_rtgroup *rtg,
unsigned long long xfs_rtrmapbt_calc_size(struct xfs_mount *mp,
unsigned long long len);

+struct xfs_btree_cur *xfs_rtrmapbt_mem_cursor(struct xfs_rtgroup *rtg,
+ struct xfs_trans *tp, struct xfbtree *xfbtree);
+int xfs_rtrmapbt_mem_init(struct xfs_mount *mp, struct xfbtree *xfbtree,
+ struct xfs_buftarg *btp, xfs_rgnumber_t rgno);
+
#endif /* __XFS_RTRMAP_BTREE_H__ */
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index da23dac22c3f08..960716c387cc2b 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -57,6 +57,7 @@ extern const struct xfs_btree_ops xfs_refcountbt_ops;
extern const struct xfs_btree_ops xfs_rmapbt_ops;
extern const struct xfs_btree_ops xfs_rmapbt_mem_ops;
extern const struct xfs_btree_ops xfs_rtrmapbt_ops;
+extern const struct xfs_btree_ops xfs_rtrmapbt_mem_ops;

static inline bool xfs_btree_is_bno(const struct xfs_btree_ops *ops)
{
@@ -98,8 +99,14 @@ static inline bool xfs_btree_is_mem_rmap(const struct xfs_btree_ops *ops)
{
return ops == &xfs_rmapbt_mem_ops;
}
+
+static inline bool xfs_btree_is_mem_rtrmap(const struct xfs_btree_ops *ops)
+{
+ return ops == &xfs_rtrmapbt_mem_ops;
+}
#else
# define xfs_btree_is_mem_rmap(...) (false)
+# define xfs_btree_is_mem_rtrmap(...) (false)
#endif

static inline bool xfs_btree_is_rtrmap(const struct xfs_btree_ops *ops)
diff --git a/fs/xfs/scrub/rtrmap_repair.c b/fs/xfs/scrub/rtrmap_repair.c
index 60e317725dea86..b376bcc8d1d2ed 100644
--- a/fs/xfs/scrub/rtrmap_repair.c
+++ b/fs/xfs/scrub/rtrmap_repair.c
@@ -12,6 +12,8 @@
#include "xfs_defer.h"
#include "xfs_btree.h"
#include "xfs_btree_staging.h"
+#include "xfs_buf_mem.h"
+#include "xfs_btree_mem.h"
#include "xfs_bit.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
@@ -64,24 +66,13 @@
* We use the 'xrep_rtrmap' prefix for all the rmap functions.
*/

-/*
- * Packed rmap record. The UNWRITTEN flags are hidden in the upper bits of
- * offset, just like the on-disk record.
- */
-struct xrep_rtrmap_extent {
- xfs_rgblock_t startblock;
- xfs_extlen_t blockcount;
- uint64_t owner;
- uint64_t offset;
-} __packed;
-
/* Context for collecting rmaps */
struct xrep_rtrmap {
/* new rtrmapbt information */
struct xrep_newbt new_btree;

/* rmap records generated from primary metadata */
- struct xfarray *rtrmap_records;
+ struct xfbtree rtrmap_btree;

struct xfs_scrub *sc;

@@ -91,8 +82,11 @@ struct xrep_rtrmap {
/* inode scan cursor */
struct xchk_iscan iscan;

- /* get_records()'s position in the free space record array. */
- xfarray_idx_t array_cur;
+ /* in-memory btree cursor for the ->get_blocks walk */
+ struct xfs_btree_cur *mcur;
+
+ /* Number of records we're staging in the new btree. */
+ uint64_t nr_records;
};

/* Set us up to repair rt reverse mapping btrees. */
@@ -101,6 +95,14 @@ xrep_setup_rtrmapbt(
struct xfs_scrub *sc)
{
struct xrep_rtrmap *rr;
+ char *descr;
+ int error;
+
+ descr = xchk_xfile_rtgroup_descr(sc, "reverse mapping records");
+ error = xrep_setup_xfbtree(sc, descr);
+ kfree(descr);
+ if (error)
+ return error;

rr = kzalloc(sizeof(struct xrep_rtrmap), XCHK_GFP_FLAGS);
if (!rr)
@@ -135,11 +137,6 @@ xrep_rtrmap_stash(
uint64_t offset,
unsigned int flags)
{
- struct xrep_rtrmap_extent rre = {
- .startblock = startblock,
- .blockcount = blockcount,
- .owner = owner,
- };
struct xfs_rmap_irec rmap = {
.rm_startblock = startblock,
.rm_blockcount = blockcount,
@@ -148,6 +145,7 @@ xrep_rtrmap_stash(
.rm_flags = flags,
};
struct xfs_scrub *sc = rr->sc;
+ struct xfs_btree_cur *mcur;
int error = 0;

if (xchk_should_terminate(sc, &error))
@@ -155,8 +153,18 @@ xrep_rtrmap_stash(

trace_xrep_rtrmap_found(sc->mp, &rmap);

- rre.offset = xfs_rmap_irec_offset_pack(&rmap);
- return xfarray_append(rr->rtrmap_records, &rre);
+ /* Add entry to in-memory btree. */
+ mcur = xfs_rtrmapbt_mem_cursor(sc->sr.rtg, sc->tp, &rr->rtrmap_btree);
+ error = xfs_rmap_map_raw(mcur, &rmap);
+ xfs_btree_del_cursor(mcur, error);
+ if (error)
+ goto out_cancel;
+
+ return xfbtree_trans_commit(&rr->rtrmap_btree, sc->tp);
+
+out_cancel:
+ xfbtree_trans_cancel(&rr->rtrmap_btree, sc->tp);
+ return error;
}

/* Finding all file and bmbt extents. */
@@ -395,6 +403,24 @@ xrep_rtrmap_scan_ag(
return error;
}

+/* Count and check all collected records. */
+STATIC int
+xrep_rtrmap_check_record(
+ struct xfs_btree_cur *cur,
+ const struct xfs_rmap_irec *rec,
+ void *priv)
+{
+ struct xrep_rtrmap *rr = priv;
+ int error;
+
+ error = xrep_rtrmap_check_mapping(rr->sc, rec);
+ if (error)
+ return error;
+
+ rr->nr_records++;
+ return 0;
+}
+
/* Generate all the reverse-mappings for the realtime device. */
STATIC int
xrep_rtrmap_find_rmaps(
@@ -403,6 +429,7 @@ xrep_rtrmap_find_rmaps(
struct xfs_scrub *sc = rr->sc;
struct xfs_perag *pag = NULL;
struct xfs_inode *ip;
+ struct xfs_btree_cur *mcur;
int error;

/* Generate rmaps for the realtime superblock */
@@ -468,7 +495,19 @@ xrep_rtrmap_find_rmaps(
}
}

- return 0;
+ /*
+ * Now that we have everything locked again, we need to count the
+ * number of rmap records stashed in the btree. This should reflect
+ * all actively-owned rt files in the filesystem. At the same time,
+ * check all our records before we start building a new btree, which
+ * requires the rtbitmap lock.
+ */
+ mcur = xfs_rtrmapbt_mem_cursor(rr->sc->sr.rtg, NULL, &rr->rtrmap_btree);
+ rr->nr_records = 0;
+ error = xfs_rmap_query_all(mcur, xrep_rtrmap_check_record, rr);
+ xfs_btree_del_cursor(mcur, error);
+
+ return error;
}

/* Building the new rtrmap btree. */
@@ -482,29 +521,25 @@ xrep_rtrmap_get_records(
unsigned int nr_wanted,
void *priv)
{
- struct xrep_rtrmap_extent rec;
- struct xfs_rmap_irec *irec = &cur->bc_rec.r;
struct xrep_rtrmap *rr = priv;
union xfs_btree_rec *block_rec;
unsigned int loaded;
int error;

for (loaded = 0; loaded < nr_wanted; loaded++, idx++) {
- error = xfarray_load_next(rr->rtrmap_records, &rr->array_cur,
- &rec);
+ int stat = 0;
+
+ error = xfs_btree_increment(rr->mcur, 0, &stat);
if (error)
return error;
-
- irec->rm_startblock = rec.startblock;
- irec->rm_blockcount = rec.blockcount;
- irec->rm_owner = rec.owner;
-
- if (xfs_rmap_irec_offset_unpack(rec.offset, irec) != NULL)
+ if (!stat)
return -EFSCORRUPTED;

- error = xrep_rtrmap_check_mapping(rr->sc, irec);
+ error = xfs_rmap_get_rec(rr->mcur, &cur->bc_rec.r, &stat);
if (error)
return error;
+ if (!stat)
+ return -EFSCORRUPTED;

block_rec = xfs_btree_rec_addr(cur, idx, block);
cur->bc_ops->init_rec_from_cur(cur, block_rec);
@@ -549,7 +584,6 @@ xrep_rtrmap_build_new_tree(
struct xfs_scrub *sc = rr->sc;
struct xfs_rtgroup *rtg = sc->sr.rtg;
struct xfs_btree_cur *rmap_cur;
- uint64_t nr_records;
int error;

/*
@@ -569,11 +603,9 @@ xrep_rtrmap_build_new_tree(
rmap_cur = xfs_rtrmapbt_init_cursor(NULL, rtg);
xfs_btree_stage_ifakeroot(rmap_cur, &rr->new_btree.ifake);

- nr_records = xfarray_length(rr->rtrmap_records);
-
/* Compute how many blocks we'll need for the rmaps collected. */
error = xfs_btree_bload_compute_geometry(rmap_cur,
- &rr->new_btree.bload, nr_records);
+ &rr->new_btree.bload, rr->nr_records);
if (error)
goto err_cur;

@@ -599,12 +631,20 @@ xrep_rtrmap_build_new_tree(
if (error)
goto err_cur;

+ /*
+ * Create a cursor to the in-memory btree so that we can bulk load the
+ * new btree.
+ */
+ rr->mcur = xfs_rtrmapbt_mem_cursor(sc->sr.rtg, NULL, &rr->rtrmap_btree);
+ error = xfs_btree_goto_left_edge(rr->mcur);
+ if (error)
+ goto err_mcur;
+
/* Add all observed rmap records. */
rr->new_btree.ifake.if_fork->if_format = XFS_DINODE_FMT_META_BTREE;
- rr->array_cur = XFARRAY_CURSOR_INIT;
error = xfs_btree_bload(rmap_cur, &rr->new_btree.bload, rr);
if (error)
- goto err_cur;
+ goto err_mcur;

/*
* Install the new rtrmap btree in the inode. After this point the old
@@ -614,6 +654,14 @@ xrep_rtrmap_build_new_tree(
xfs_rtrmapbt_commit_staged_btree(rmap_cur, sc->tp);
xrep_inode_set_nblocks(rr->sc, rr->new_btree.ifake.if_blocks);
xfs_btree_del_cursor(rmap_cur, 0);
+ xfs_btree_del_cursor(rr->mcur, 0);
+ rr->mcur = NULL;
+
+ /*
+ * Now that we've written the new btree to disk, we don't need to keep
+ * updating the in-memory btree. Abort the scan to stop live updates.
+ */
+ xchk_iscan_abort(&rr->iscan);

/* Dispose of any unused blocks and the accounting information. */
error = xrep_newbt_commit(&rr->new_btree);
@@ -622,6 +670,8 @@ xrep_rtrmap_build_new_tree(

return xrep_roll_trans(sc);

+err_mcur:
+ xfs_btree_del_cursor(rr->mcur, error);
err_cur:
xfs_btree_del_cursor(rmap_cur, error);
xrep_newbt_cancel(&rr->new_btree);
@@ -658,16 +708,13 @@ xrep_rtrmap_setup_scan(
struct xrep_rtrmap *rr)
{
struct xfs_scrub *sc = rr->sc;
- char *descr;
int error;

xfsb_bitmap_init(&rr->old_rtrmapbt_blocks);

/* Set up some storage */
- descr = xchk_xfile_rtgroup_descr(sc, "reverse mapping records");
- error = xfarray_create(descr, 0, sizeof(struct xrep_rtrmap_extent),
- &rr->rtrmap_records);
- kfree(descr);
+ error = xfs_rtrmapbt_mem_init(sc->mp, &rr->rtrmap_btree, sc->xmbtp,
+ rtg_rgno(sc->sr.rtg));
if (error)
goto out_bitmap;

@@ -686,7 +733,7 @@ xrep_rtrmap_teardown(
struct xrep_rtrmap *rr)
{
xchk_iscan_teardown(&rr->iscan);
- xfarray_destroy(rr->rtrmap_records);
+ xfbtree_destroy(&rr->rtrmap_btree);
xfsb_bitmap_destroy(&rr->old_rtrmapbt_blocks);
}

diff --git a/fs/xfs/xfs_stats.c b/fs/xfs/xfs_stats.c
index f94fb70b524ffb..b7f2988bc03bb7 100644
--- a/fs/xfs/xfs_stats.c
+++ b/fs/xfs/xfs_stats.c
@@ -53,7 +53,8 @@ int xfs_stats_format(struct xfsstats __percpu *stats, char *buf)
{ "refcntbt", xfsstats_offset(xs_rmap_mem_2) },
{ "rmapbt_mem", xfsstats_offset(xs_rcbag_2) },
{ "rcbagbt", xfsstats_offset(xs_rtrmap_2) },
- { "rtrmapbt", xfsstats_offset(xs_qm_dqreclaims)},
+ { "rtrmapbt", xfsstats_offset(xs_rtrmap_mem_2)},
+ { "rtrmapbt_mem", xfsstats_offset(xs_qm_dqreclaims)},
/* we print both series of quota information together */
{ "qm", xfsstats_offset(xs_xstrat_bytes)},
};
diff --git a/fs/xfs/xfs_stats.h b/fs/xfs/xfs_stats.h
index 05dc69c6d94906..9c47de5dff2dd6 100644
--- a/fs/xfs/xfs_stats.h
+++ b/fs/xfs/xfs_stats.h
@@ -128,6 +128,7 @@ struct __xfsstats {
uint32_t xs_rmap_mem_2[__XBTS_MAX];
uint32_t xs_rcbag_2[__XBTS_MAX];
uint32_t xs_rtrmap_2[__XBTS_MAX];
+ uint32_t xs_rtrmap_mem_2[__XBTS_MAX];
uint32_t xs_qm_dqreclaims;
uint32_t xs_qm_dqreclaim_misses;
uint32_t xs_qm_dquot_dups;