Merge tag 'bcachefs-2024-09-21' of git://evilpiepirate.org/bcachefs

Pull bcachefs updates from Kent Overstreet:

 - rcu_pending, btree key cache rework: this solves lock contenting in
   the key cache, eliminating the biggest source of the srcu lock hold
   time warnings, and drastically improving performance on some metadata
   heavy workloads - on multithreaded creates we're now 3-4x faster than
   xfs.

 - We're now using an rhashtable instead of the system inode hash table;
   this is another significant performance improvement on multithreaded
   metadata workloads, eliminating more lock contention.

 - for_each_btree_key_in_subvolume_upto(): new helper for iterating over
   keys within a specific subvolume, eliminating a lot of open coded
   "subvolume_get_snapshot()" and also fixing another source of srcu
   lock time warnings, by running each loop iteration in its own
   transaction (as the existing for_each_btree_key() does).

 - More work on btree_trans locking asserts; we now assert that we don't
   hold btree node locks when trans->locked is false, which is important
   because we don't use lockdep for tracking individual btree node
   locks.

 - Some cleanups and improvements in the bset.c btree node lookup code,
   from Alan.

 - Rework of btree node pinning, which we use in backpointers fsck. The
   old hacky implementation, where the shrinker just skipped over nodes
   in the pinned range, was causing OOMs; instead we now use another
   shrinker with a much higher seeks number for pinned nodes.

 - Rebalance now uses BCH_WRITE_ONLY_SPECIFIED_DEVS; this fixes an issue
   where rebalance would sometimes fall back to allocating from the full
   filesystem, which is not what we want when it's trying to move data
   to a specific target.

 - Use __GFP_ACCOUNT, GFP_RECLAIMABLE for btree node, key cache
   allocations.

 - Idmap mounts are now supported (Hongbo Li)

 - Rename whiteouts are now supported (Hongbo Li)

 - Erasure coding can now handle devices being marked as failed, or
   forcibly removed. We still need the evacuate path for erasure coding,
   but it's getting very close to ready for people to start using.

* tag 'bcachefs-2024-09-21' of git://evilpiepirate.org/bcachefs: (99 commits)
  bcachefs: return err ptr instead of null in read sb clean
  bcachefs: Remove duplicated include in backpointers.c
  bcachefs: Don't drop devices with stripe pointers
  bcachefs: bch2_ec_stripe_head_get() now checks for change in rw devices
  bcachefs: bch_fs.rw_devs_change_count
  bcachefs: bch2_dev_remove_stripes()
  bcachefs: bch2_trigger_ptr() calculates sectors even when no device
  bcachefs: improve error messages in bch2_ec_read_extent()
  bcachefs: improve error message on too few devices for ec
  bcachefs: improve bch2_new_stripe_to_text()
  bcachefs: ec_stripe_head.nr_created
  bcachefs: bch_stripe.disk_label
  bcachefs: stripe_to_mem()
  bcachefs: EIO errcode cleanup
  bcachefs: Rework btree node pinning
  bcachefs: split up btree cache counters for live, freeable
  bcachefs: btree cache counters should be size_t
  bcachefs: Don't count "skipped access bit" as touched in btree cache scan
  bcachefs: Failed devices no longer require mounting in degraded mode
  bcachefs: bch2_dev_rcu_noerror()
  ...

Author: torvalds

Documentation/filesystems/bcachefs/CodingStyle.rst

@@ -175,7 +175,7 @@ errors in our thinking by running our code and seeing what happens. If your
 time is being wasted because your tools are bad or too slow - don't accept it,
 fix it.
 
-Put effort into your documentation, commmit messages, and code comments - but
+Put effort into your documentation, commit messages, and code comments - but
 don't go overboard. A good commit message is wonderful - but if the information
 was important enough to go in a commit message, ask yourself if it would be
 even better as a code comment.

fs/bcachefs/Kconfig

@@ -87,6 +87,13 @@ config BCACHEFS_SIX_OPTIMISTIC_SPIN
 	is held by another thread, spin for a short while, as long as the
 	thread owning the lock is running.
 
+config BCACHEFS_PATH_TRACEPOINTS
+	bool "Extra btree_path tracepoints"
+	depends on BCACHEFS_FS
+	help
+	Enable extra tracepoints for debugging btree_path operations; we don't
+	normally want these enabled because they happen at very high rates.
+
 config MEAN_AND_VARIANCE_UNIT_TEST
 	tristate "mean_and_variance unit tests" if !KUNIT_ALL_TESTS
 	depends on KUNIT

fs/bcachefs/Makefile

@@ -69,6 +69,7 @@ bcachefs-y		:=	\
 	printbuf.o		\
 	quota.o			\
 	rebalance.o		\
+	rcu_pending.o		\
 	recovery.o		\
 	recovery_passes.o	\
 	reflink.o		\

fs/bcachefs/acl.c

@@ -361,7 +361,7 @@ int bch2_set_acl(struct mnt_idmap *idmap,
 	bch2_trans_begin(trans);
 	acl = _acl;
 
-	ret   = bch2_subvol_is_ro_trans(trans, inode->ei_subvol) ?:
+	ret   = bch2_subvol_is_ro_trans(trans, inode->ei_inum.subvol) ?:
 		bch2_inode_peek(trans, &inode_iter, &inode_u, inode_inum(inode),
 			      BTREE_ITER_intent);
 	if (ret)

fs/bcachefs/alloc_background.c

@@ -30,6 +30,7 @@
 #include <linux/rcupdate.h>
 #include <linux/sched/task.h>
 #include <linux/sort.h>
+#include <linux/jiffies.h>
 
 static void bch2_discard_one_bucket_fast(struct bch_dev *, u64);
 
@@ -2183,7 +2184,7 @@ int bch2_dev_freespace_init(struct bch_fs *c, struct bch_dev *ca,
 	 * freespace/need_discard/need_gc_gens btrees as needed:
 	 */
 	while (1) {
-		if (last_updated + HZ * 10 < jiffies) {
+		if (time_after(jiffies, last_updated + HZ * 10)) {
 			bch_info(ca, "%s: currently at %llu/%llu",
 				 __func__, iter.pos.offset, ca->mi.nbuckets);
 			last_updated = jiffies;
@@ -2297,6 +2298,36 @@ int bch2_fs_freespace_init(struct bch_fs *c)
 	return 0;
 }
 
+/* device removal */
+
+int bch2_dev_remove_alloc(struct bch_fs *c, struct bch_dev *ca)
+{
+	struct bpos start	= POS(ca->dev_idx, 0);
+	struct bpos end		= POS(ca->dev_idx, U64_MAX);
+	int ret;
+
+	/*
+	 * We clear the LRU and need_discard btrees first so that we don't race
+	 * with bch2_do_invalidates() and bch2_do_discards()
+	 */
+	ret =   bch2_dev_remove_stripes(c, ca->dev_idx) ?:
+		bch2_btree_delete_range(c, BTREE_ID_lru, start, end,
+					BTREE_TRIGGER_norun, NULL) ?:
+		bch2_btree_delete_range(c, BTREE_ID_need_discard, start, end,
+					BTREE_TRIGGER_norun, NULL) ?:
+		bch2_btree_delete_range(c, BTREE_ID_freespace, start, end,
+					BTREE_TRIGGER_norun, NULL) ?:
+		bch2_btree_delete_range(c, BTREE_ID_backpointers, start, end,
+					BTREE_TRIGGER_norun, NULL) ?:
+		bch2_btree_delete_range(c, BTREE_ID_bucket_gens, start, end,
+					BTREE_TRIGGER_norun, NULL) ?:
+		bch2_btree_delete_range(c, BTREE_ID_alloc, start, end,
+					BTREE_TRIGGER_norun, NULL) ?:
+		bch2_dev_usage_remove(c, ca->dev_idx);
+	bch_err_msg(ca, ret, "removing dev alloc info");
+	return ret;
+}
+
 /* Bucket IO clocks: */
 
 int bch2_bucket_io_time_reset(struct btree_trans *trans, unsigned dev,
@@ -2432,13 +2463,15 @@ static bool bch2_dev_has_open_write_point(struct bch_fs *c, struct bch_dev *ca)
 /* device goes ro: */
 void bch2_dev_allocator_remove(struct bch_fs *c, struct bch_dev *ca)
 {
-	unsigned i;
+	lockdep_assert_held(&c->state_lock);
 
 	/* First, remove device from allocation groups: */
 
-	for (i = 0; i < ARRAY_SIZE(c->rw_devs); i++)
+	for (unsigned i = 0; i < ARRAY_SIZE(c->rw_devs); i++)
 		clear_bit(ca->dev_idx, c->rw_devs[i].d);
 
+	c->rw_devs_change_count++;
+
 	/*
 	 * Capacity is calculated based off of devices in allocation groups:
 	 */
@@ -2467,11 +2500,13 @@ void bch2_dev_allocator_remove(struct bch_fs *c, struct bch_dev *ca)
 /* device goes rw: */
 void bch2_dev_allocator_add(struct bch_fs *c, struct bch_dev *ca)
 {
-	unsigned i;
+	lockdep_assert_held(&c->state_lock);
 
-	for (i = 0; i < ARRAY_SIZE(c->rw_devs); i++)
+	for (unsigned i = 0; i < ARRAY_SIZE(c->rw_devs); i++)
 		if (ca->mi.data_allowed & (1 << i))
 			set_bit(ca->dev_idx, c->rw_devs[i].d);
+
+	c->rw_devs_change_count++;
 }
 
 void bch2_dev_allocator_background_exit(struct bch_dev *ca)

fs/bcachefs/alloc_background.h

@@ -16,7 +16,7 @@ enum bch_validate_flags;
 static inline bool bch2_dev_bucket_exists(struct bch_fs *c, struct bpos pos)
 {
 	rcu_read_lock();
-	struct bch_dev *ca = bch2_dev_rcu(c, pos.inode);
+	struct bch_dev *ca = bch2_dev_rcu_noerror(c, pos.inode);
 	bool ret = ca && bucket_valid(ca, pos.offset);
 	rcu_read_unlock();
 	return ret;
@@ -338,6 +338,7 @@ static inline const struct bch_backpointer *alloc_v4_backpointers_c(const struct
 
 int bch2_dev_freespace_init(struct bch_fs *, struct bch_dev *, u64, u64);
 int bch2_fs_freespace_init(struct bch_fs *);
+int bch2_dev_remove_alloc(struct bch_fs *, struct bch_dev *);
 
 void bch2_recalc_capacity(struct bch_fs *);
 u64 bch2_min_rw_member_capacity(struct bch_fs *);

fs/bcachefs/alloc_foreground.c

@@ -600,6 +600,7 @@ static struct open_bucket *bch2_bucket_alloc_trans(struct btree_trans *trans,
 				      enum bch_watermark watermark,
 				      enum bch_data_type data_type,
 				      struct closure *cl,
+				      bool nowait,
 				      struct bch_dev_usage *usage)
 {
 	struct bch_fs *c = trans->c;
@@ -609,7 +610,7 @@ static struct open_bucket *bch2_bucket_alloc_trans(struct btree_trans *trans,
 	struct bucket_alloc_state s = {
 		.btree_bitmap = data_type == BCH_DATA_btree,
 	};
-	bool waiting = false;
+	bool waiting = nowait;
 again:
 	bch2_dev_usage_read_fast(ca, usage);
 	avail = dev_buckets_free(ca, *usage, watermark);
@@ -685,7 +686,7 @@ struct open_bucket *bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca,
 
 	bch2_trans_do(c, NULL, NULL, 0,
 		      PTR_ERR_OR_ZERO(ob = bch2_bucket_alloc_trans(trans, ca, watermark,
-							data_type, cl, &usage)));
+							data_type, cl, false, &usage)));
 	return ob;
 }
 
@@ -748,7 +749,6 @@ static int add_new_bucket(struct bch_fs *c,
 			   unsigned nr_replicas,
 			   unsigned *nr_effective,
 			   bool *have_cache,
-			   unsigned flags,
 			   struct open_bucket *ob)
 {
 	unsigned durability = ob_dev(c, ob)->mi.durability;
@@ -775,7 +775,7 @@ int bch2_bucket_alloc_set_trans(struct btree_trans *trans,
 		      unsigned nr_replicas,
 		      unsigned *nr_effective,
 		      bool *have_cache,
-		      unsigned flags,
+		      enum bch_write_flags flags,
 		      enum bch_data_type data_type,
 		      enum bch_watermark watermark,
 		      struct closure *cl)
@@ -801,7 +801,8 @@ int bch2_bucket_alloc_set_trans(struct btree_trans *trans,
 			continue;
 		}
 
-		ob = bch2_bucket_alloc_trans(trans, ca, watermark, data_type, cl, &usage);
+		ob = bch2_bucket_alloc_trans(trans, ca, watermark, data_type,
+					     cl, flags & BCH_WRITE_ALLOC_NOWAIT, &usage);
 		if (!IS_ERR(ob))
 			bch2_dev_stripe_increment_inlined(ca, stripe, &usage);
 		bch2_dev_put(ca);
@@ -815,7 +816,7 @@ int bch2_bucket_alloc_set_trans(struct btree_trans *trans,
 
 		if (add_new_bucket(c, ptrs, devs_may_alloc,
 				   nr_replicas, nr_effective,
-				   have_cache, flags, ob)) {
+				   have_cache, ob)) {
 			ret = 0;
 			break;
 		}
@@ -841,7 +842,7 @@ static int bucket_alloc_from_stripe(struct btree_trans *trans,
 			 unsigned *nr_effective,
 			 bool *have_cache,
 			 enum bch_watermark watermark,
-			 unsigned flags,
+			 enum bch_write_flags flags,
 			 struct closure *cl)
 {
 	struct bch_fs *c = trans->c;
@@ -883,7 +884,7 @@ static int bucket_alloc_from_stripe(struct btree_trans *trans,
 
 	ret = add_new_bucket(c, ptrs, devs_may_alloc,
 			     nr_replicas, nr_effective,
-			     have_cache, flags, ob);
+			     have_cache, ob);
 out_put_head:
 	bch2_ec_stripe_head_put(c, h);
 	return ret;
@@ -922,7 +923,7 @@ static int bucket_alloc_set_writepoint(struct bch_fs *c,
 				       unsigned nr_replicas,
 				       unsigned *nr_effective,
 				       bool *have_cache,
-				       bool ec, unsigned flags)
+				       bool ec)
 {
 	struct open_buckets ptrs_skip = { .nr = 0 };
 	struct open_bucket *ob;
@@ -934,7 +935,7 @@ static int bucket_alloc_set_writepoint(struct bch_fs *c,
 					have_cache, ec, ob))
 			ret = add_new_bucket(c, ptrs, devs_may_alloc,
 				       nr_replicas, nr_effective,
-				       have_cache, flags, ob);
+				       have_cache, ob);
 		else
 			ob_push(c, &ptrs_skip, ob);
 	}
@@ -950,8 +951,7 @@ static int bucket_alloc_set_partial(struct bch_fs *c,
 				    unsigned nr_replicas,
 				    unsigned *nr_effective,
 				    bool *have_cache, bool ec,
-				    enum bch_watermark watermark,
-				    unsigned flags)
+				    enum bch_watermark watermark)
 {
 	int i, ret = 0;
 
@@ -983,7 +983,7 @@ static int bucket_alloc_set_partial(struct bch_fs *c,
 
 			ret = add_new_bucket(c, ptrs, devs_may_alloc,
 					     nr_replicas, nr_effective,
-					     have_cache, flags, ob);
+					     have_cache, ob);
 			if (ret)
 				break;
 		}
@@ -1003,7 +1003,7 @@ static int __open_bucket_add_buckets(struct btree_trans *trans,
 			unsigned *nr_effective,
 			bool *have_cache,
 			enum bch_watermark watermark,
-			unsigned flags,
+			enum bch_write_flags flags,
 			struct closure *_cl)
 {
 	struct bch_fs *c = trans->c;
@@ -1022,18 +1022,15 @@ static int __open_bucket_add_buckets(struct btree_trans *trans,
 	open_bucket_for_each(c, ptrs, ob, i)
 		__clear_bit(ob->dev, devs.d);
 
-	if (erasure_code && ec_open_bucket(c, ptrs))
-		return 0;
-
 	ret = bucket_alloc_set_writepoint(c, ptrs, wp, &devs,
 				 nr_replicas, nr_effective,
-				 have_cache, erasure_code, flags);
+				 have_cache, erasure_code);
 	if (ret)
 		return ret;
 
 	ret = bucket_alloc_set_partial(c, ptrs, wp, &devs,
 				 nr_replicas, nr_effective,
-				 have_cache, erasure_code, watermark, flags);
+				 have_cache, erasure_code, watermark);
 	if (ret)
 		return ret;
 
@@ -1074,12 +1071,12 @@ static int open_bucket_add_buckets(struct btree_trans *trans,
 			unsigned *nr_effective,
 			bool *have_cache,
 			enum bch_watermark watermark,
-			unsigned flags,
+			enum bch_write_flags flags,
 			struct closure *cl)
 {
 	int ret;
 
-	if (erasure_code) {
+	if (erasure_code && !ec_open_bucket(trans->c, ptrs)) {
 		ret = __open_bucket_add_buckets(trans, ptrs, wp,
 				devs_have, target, erasure_code,
 				nr_replicas, nr_effective, have_cache,
@@ -1376,7 +1373,7 @@ int bch2_alloc_sectors_start_trans(struct btree_trans *trans,
 			     unsigned nr_replicas,
 			     unsigned nr_replicas_required,
 			     enum bch_watermark watermark,
-			     unsigned flags,
+			     enum bch_write_flags flags,
 			     struct closure *cl,
 			     struct write_point **wp_ret)
 {
@@ -1392,8 +1389,6 @@ int bch2_alloc_sectors_start_trans(struct btree_trans *trans,
 	if (!IS_ENABLED(CONFIG_BCACHEFS_ERASURE_CODING))
 		erasure_code = false;
 
-	BUG_ON(flags & BCH_WRITE_ONLY_SPECIFIED_DEVS);
-
 	BUG_ON(!nr_replicas || !nr_replicas_required);
 retry:
 	ptrs.nr		= 0;
@@ -1498,11 +1493,12 @@ int bch2_alloc_sectors_start_trans(struct btree_trans *trans,
 	    try_decrease_writepoints(trans, write_points_nr))
 		goto retry;
 
-	if (bch2_err_matches(ret, BCH_ERR_open_buckets_empty) ||
+	if (cl && bch2_err_matches(ret, BCH_ERR_open_buckets_empty))
+		ret = -BCH_ERR_bucket_alloc_blocked;
+
+	if (cl && !(flags & BCH_WRITE_ALLOC_NOWAIT) &&
 	    bch2_err_matches(ret, BCH_ERR_freelist_empty))
-		return cl
-			? -BCH_ERR_bucket_alloc_blocked
-			: -BCH_ERR_ENOSPC_bucket_alloc;
+		ret = -BCH_ERR_bucket_alloc_blocked;
 
 	return ret;
 }
@@ -1733,13 +1729,6 @@ void bch2_dev_alloc_debug_to_text(struct printbuf *out, struct bch_dev *ca)
 	for (unsigned i = 0; i < ARRAY_SIZE(c->open_buckets); i++)
 		nr[c->open_buckets[i].data_type]++;
 
-	printbuf_tabstops_reset(out);
-	printbuf_tabstop_push(out, 12);
-	printbuf_tabstop_push(out, 16);
-	printbuf_tabstop_push(out, 16);
-	printbuf_tabstop_push(out, 16);
-	printbuf_tabstop_push(out, 16);
-
 	bch2_dev_usage_to_text(out, ca, &stats);
 
 	prt_newline(out);

fs/bcachefs/alloc_foreground.h

@@ -155,9 +155,10 @@ static inline bool bch2_bucket_is_open_safe(struct bch_fs *c, unsigned dev, u64
 	return ret;
 }
 
+enum bch_write_flags;
 int bch2_bucket_alloc_set_trans(struct btree_trans *, struct open_buckets *,
 		      struct dev_stripe_state *, struct bch_devs_mask *,
-		      unsigned, unsigned *, bool *, unsigned,
+		      unsigned, unsigned *, bool *, enum bch_write_flags,
 		      enum bch_data_type, enum bch_watermark,
 		      struct closure *);
 
@@ -167,7 +168,7 @@ int bch2_alloc_sectors_start_trans(struct btree_trans *,
 				   struct bch_devs_list *,
 				   unsigned, unsigned,
 				   enum bch_watermark,
-				   unsigned,
+				   enum bch_write_flags,
 				   struct closure *,
 				   struct write_point **);