Re: [PATCH] bcachefs: bch_member.btree_allocated_bitmap

From: Hongbo Li
Date: Sun Apr 14 2024 - 21:12:30 EST



On 2024/4/14 5:57, Kent Overstreet wrote:
For those interested, this is a good tour of the facilities for rolling
out new on disk format features.

-- >8 --

This adds a small (64 bit) per-device bitmap that tracks ranges that
have btree nodes, for accelerating btree node scan if it is ever needed.

- New helpers, bch2_dev_btree_bitmap_marked() and
bch2_dev_bitmap_mark(), for checking and updating the bitmap

- Interior btree update path updates the bitmaps when required

- The check_allocations pass has a new fsck_err check,
btree_bitmap_not_marked

- New on disk format version, mi_btree_mitmap, which indicates the new
bitmap is present

- Upgrade table lists the required recovery pass and expected fsck error

- Btree node scan uses the bitmap to skip ranges if we're on the new
version

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
---
fs/bcachefs/bcachefs_format.h | 7 ++--
fs/bcachefs/btree_gc.c | 13 +++++++
fs/bcachefs/btree_node_scan.c | 9 +++--
fs/bcachefs/btree_update_interior.c | 24 +++++++++++++
fs/bcachefs/sb-downgrade.c | 5 ++-
fs/bcachefs/sb-errors_types.h | 3 +-
fs/bcachefs/sb-members.c | 53 +++++++++++++++++++++++++++++
fs/bcachefs/sb-members.h | 21 ++++++++++++
fs/bcachefs/sb-members_types.h | 2 ++
9 files changed, 131 insertions(+), 6 deletions(-)

diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h
index 9480f1b44f07..085987435a5e 100644
--- a/fs/bcachefs/bcachefs_format.h
+++ b/fs/bcachefs/bcachefs_format.h
@@ -578,7 +578,8 @@ struct bch_member {
__le64 nbuckets; /* device size */
__le16 first_bucket; /* index of first bucket used */
__le16 bucket_size; /* sectors */
- __le32 pad;
+ __u8 btree_bitmap_shift;
+ __u8 pad[3];
__le64 last_mount; /* time_t */
__le64 flags;
@@ -587,6 +588,7 @@ struct bch_member {
__le64 errors_at_reset[BCH_MEMBER_ERROR_NR];
__le64 errors_reset_time;
__le64 seq;
+ __le64 btree_allocated_bitmap;
};
#define BCH_MEMBER_V1_BYTES 56
@@ -876,7 +878,8 @@ struct bch_sb_field_downgrade {
x(rebalance_work, BCH_VERSION(1, 3)) \
x(member_seq, BCH_VERSION(1, 4)) \
x(subvolume_fs_parent, BCH_VERSION(1, 5)) \
- x(btree_subvolume_children, BCH_VERSION(1, 6))
+ x(btree_subvolume_children, BCH_VERSION(1, 6)) \
+ x(mi_btree_bitmap, BCH_VERSION(1, 7))
enum bcachefs_metadata_version {
bcachefs_metadata_version_min = 9,
diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index 10c41cf89212..a77c723a9cef 100644
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -822,6 +822,7 @@ static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
struct bch_fs *c = trans->c;
struct bkey deleted = KEY(0, 0, 0);
struct bkey_s_c old = (struct bkey_s_c) { &deleted, NULL };
+ struct printbuf buf = PRINTBUF;
int ret = 0;
deleted.p = k->k->p;
@@ -842,11 +843,23 @@ static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
if (ret)
goto err;
+ if (mustfix_fsck_err_on(level && !bch2_dev_btree_bitmap_marked(c, *k),
+ c, btree_bitmap_not_marked,
+ "btree ptr not marked in member info btree allocated bitmap\n %s",
+ (bch2_bkey_val_to_text(&buf, c, *k),
+ buf.buf))) {
+ mutex_lock(&c->sb_lock);
+ bch2_dev_btree_bitmap_mark(c, *k);
+ bch2_write_super(c);
+ mutex_unlock(&c->sb_lock);
+ }
+
ret = commit_do(trans, NULL, NULL, 0,
bch2_key_trigger(trans, btree_id, level, old,
unsafe_bkey_s_c_to_s(*k), BTREE_TRIGGER_gc));
fsck_err:
err:
+ printbuf_exit(&buf);
bch_err_fn(c, ret);
return ret;
}
diff --git a/fs/bcachefs/btree_node_scan.c b/fs/bcachefs/btree_node_scan.c
index 20f2b37c4474..866bd278439f 100644
--- a/fs/bcachefs/btree_node_scan.c
+++ b/fs/bcachefs/btree_node_scan.c
@@ -205,8 +205,13 @@ static int read_btree_nodes_worker(void *p)
last_print = jiffies;
}
- try_read_btree_node(w->f, ca, bio, buf,
- bucket * ca->mi.bucket_size + bucket_offset);
+ u64 sector = bucket * ca->mi.bucket_size + bucket_offset;
+
+ if (c->sb.version_upgrade_complete >= bcachefs_metadata_version_mi_btree_bitmap &&
+ !bch2_dev_btree_bitmap_marked_sectors(ca, sector, btree_sectors(c)))
+ continue;
+
+ try_read_btree_node(w->f, ca, bio, buf, sector);
}
err:
bio_put(bio);
diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index 593241b15aa8..12ce6287416f 100644
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -21,6 +21,7 @@
#include "keylist.h"
#include "recovery_passes.h"
#include "replicas.h"
+#include "sb-members.h"
#include "super-io.h"
#include "trace.h"
@@ -644,6 +645,26 @@ static int btree_update_nodes_written_trans(struct btree_trans *trans,
return 0;
}
+static bool btree_update_new_nodes_marked_sb(struct btree_update *as)
+{
+ for_each_keylist_key(&as->new_keys, k)
+ if (!bch2_dev_btree_bitmap_marked(as->c, bkey_i_to_s_c(k)))
+ return false;
+ return true;
+}
+
+static void btree_update_new_nodes_mark_sb(struct btree_update *as)
+{
+ struct bch_fs *c = as->c;
+
+ mutex_lock(&c->sb_lock);
+ for_each_keylist_key(&as->new_keys, k)
+ bch2_dev_btree_bitmap_mark(c, bkey_i_to_s_c(k));
+
+ bch2_write_super(c);
+ mutex_unlock(&c->sb_lock);
+}
+
static void btree_update_nodes_written(struct btree_update *as)
{
struct bch_fs *c = as->c;
@@ -664,6 +685,9 @@ static void btree_update_nodes_written(struct btree_update *as)
if (ret)
goto err;
+ if (!btree_update_new_nodes_marked_sb(as))
+ btree_update_new_nodes_mark_sb(as);
+
/*
* Wait for any in flight writes to finish before we free the old nodes
* on disk:
diff --git a/fs/bcachefs/sb-downgrade.c b/fs/bcachefs/sb-downgrade.c
index 56ac8f35cdc3..90b06f8aa1df 100644
--- a/fs/bcachefs/sb-downgrade.c
+++ b/fs/bcachefs/sb-downgrade.c
@@ -51,7 +51,10 @@
BCH_FSCK_ERR_subvol_fs_path_parent_wrong) \
x(btree_subvolume_children, \
BIT_ULL(BCH_RECOVERY_PASS_check_subvols), \
- BCH_FSCK_ERR_subvol_children_not_set)
+ BCH_FSCK_ERR_subvol_children_not_set) \
+ x(mi_btree_bitmap, \
+ BIT_ULL(BCH_RECOVERY_PASS_check_allocations), \
+ BCH_FSCK_ERR_btree_bitmap_not_marked)
#define DOWNGRADE_TABLE()
diff --git a/fs/bcachefs/sb-errors_types.h b/fs/bcachefs/sb-errors_types.h
index d7d609131030..5b600c6d7aca 100644
--- a/fs/bcachefs/sb-errors_types.h
+++ b/fs/bcachefs/sb-errors_types.h
@@ -270,7 +270,8 @@
x(btree_ptr_v2_min_key_bad, 262) \
x(btree_root_unreadable_and_scan_found_nothing, 263) \
x(snapshot_node_missing, 264) \
- x(dup_backpointer_to_bad_csum_extent, 265)
+ x(dup_backpointer_to_bad_csum_extent, 265) \
+ x(btree_bitmap_not_marked, 266)
enum bch_sb_error_id {
#define x(t, n) BCH_FSCK_ERR_##t = n,
diff --git a/fs/bcachefs/sb-members.c b/fs/bcachefs/sb-members.c
index 9b7a2f300182..d5937aba0910 100644
--- a/fs/bcachefs/sb-members.c
+++ b/fs/bcachefs/sb-members.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
+#include "btree_cache.h"
#include "disk_groups.h"
#include "opts.h"
#include "replicas.h"
@@ -378,3 +379,55 @@ void bch2_dev_errors_reset(struct bch_dev *ca)
bch2_write_super(c);
mutex_unlock(&c->sb_lock);
}
+
+/*
+ * Per member "range has btree nodes" bitmap:
+ *
+ * This is so that if we ever have to run the btree node scan to repair we don't
+ * have to scan full devices:
+ */
+
+bool bch2_dev_btree_bitmap_marked(struct bch_fs *c, struct bkey_s_c k)
+{
+ bkey_for_each_ptr(bch2_bkey_ptrs_c(k), ptr)
+ if (!bch2_dev_btree_bitmap_marked_sectors(bch2_dev_bkey_exists(c, ptr->dev),
+ ptr->offset, btree_sectors(c)))
+ return false;
+ return true;
+}
+
+static void __bch2_dev_btree_bitmap_mark(struct bch_sb_field_members_v2 *mi, unsigned dev,
+ u64 start, unsigned sectors)
+{
+ struct bch_member *m = __bch2_members_v2_get_mut(mi, dev);
+ u64 bitmap = le64_to_cpu(m->btree_allocated_bitmap);
+
+ u64 end = start + sectors;
+
+ int resize = ilog2(roundup_pow_of_two(end)) - (m->btree_bitmap_shift + 6);
+ if (resize > 0) {
+ u64 new_bitmap = 0;
+
+ for (unsigned i = 0; i < 64; i++)
+ if (bitmap & BIT_ULL(i))
+ new_bitmap |= BIT_ULL(i >> resize);
+ bitmap = new_bitmap;
+ m->btree_bitmap_shift += resize;
+ }
+
+ for (unsigned bit = sectors >> m->btree_bitmap_shift;
+ bit << m->btree_bitmap_shift < end;
+ bit++)
+ bitmap |= BIT_ULL(bit);
+
+ m->btree_allocated_bitmap = cpu_to_le64(bitmap);
+}
+
+void bch2_dev_btree_bitmap_mark(struct bch_fs *c, struct bkey_s_c k)
+{
+ lockdep_assert_held(&c->sb_lock);
+
+ struct bch_sb_field_members_v2 *mi = bch2_sb_field_get(c->disk_sb.sb, members_v2);
+ bkey_for_each_ptr(bch2_bkey_ptrs_c(k), ptr)
+ __bch2_dev_btree_bitmap_mark(mi, ptr->dev, ptr->offset, btree_sectors(c));
+}
diff --git a/fs/bcachefs/sb-members.h b/fs/bcachefs/sb-members.h
index bc3bcfef7b3a..8bbad30a4370 100644
--- a/fs/bcachefs/sb-members.h
+++ b/fs/bcachefs/sb-members.h
@@ -3,6 +3,7 @@
#define _BCACHEFS_SB_MEMBERS_H
#include "darray.h"
+#include "bkey_types.h"
extern char * const bch2_member_error_strs[];
@@ -234,6 +235,8 @@ static inline struct bch_member_cpu bch2_mi_to_cpu(struct bch_member *mi)
: 1,
.freespace_initialized = BCH_MEMBER_FREESPACE_INITIALIZED(mi),
.valid = bch2_member_alive(mi),
+ .btree_bitmap_shift = mi->btree_bitmap_shift,
+ .btree_allocated_bitmap = le64_to_cpu(mi->btree_allocated_bitmap),
};
}
@@ -242,4 +245,22 @@ void bch2_sb_members_from_cpu(struct bch_fs *);
void bch2_dev_io_errors_to_text(struct printbuf *, struct bch_dev *);
void bch2_dev_errors_reset(struct bch_dev *);
+static inline bool bch2_dev_btree_bitmap_marked_sectors(struct bch_dev *ca, u64 start, unsigned sectors)
+{
+ u64 end = start + sectors;
+
+ if (end > 64 << ca->mi.btree_bitmap_shift)
+ return false;
+
+ for (unsigned bit = sectors >> ca->mi.btree_bitmap_shift;
+ bit << ca->mi.btree_bitmap_shift < end;
+ bit++)
+ if (!(ca->mi.btree_allocated_bitmap & BIT_ULL(bit)))
Should it be transferred by le64_to_cpu?
+ return false;
+ return true;
+}
+
+bool bch2_dev_btree_bitmap_marked(struct bch_fs *, struct bkey_s_c);
+void bch2_dev_btree_bitmap_mark(struct bch_fs *, struct bkey_s_c);
+
#endif /* _BCACHEFS_SB_MEMBERS_H */
diff --git a/fs/bcachefs/sb-members_types.h b/fs/bcachefs/sb-members_types.h
index 3f915536d554..c0eda888fe39 100644
--- a/fs/bcachefs/sb-members_types.h
+++ b/fs/bcachefs/sb-members_types.h
@@ -14,6 +14,8 @@ struct bch_member_cpu {
u8 durability;
u8 freespace_initialized;
u8 valid;
+ u8 btree_bitmap_shift;
+ u64 btree_allocated_bitmap;
};
#endif /* _BCACHEFS_SB_MEMBERS_H */