Update bcachefs sources to e14d7c7195 bcachefs: Compression levels

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

39 files changed, 645 insertions, 237 deletions

diff --git a/.bcachefs_revision b/.bcachefs_revision
index 9071b137..06166c86 100644
--- a/.bcachefs_revision
+++ b/.bcachefs_revision
@@ -1 +1 @@
-04f2d2ae5bd69eecd0b4bb700efdc665b09745a1
+e14d7c7195b974bbaf400f9c3f2bdaa94fc8d372
diff --git a/cmd_dump.c b/cmd_dump.c
index 59d73c3c..cc25a6a3 100644
--- a/cmd_dump.c
+++ b/cmd_dump.c
@@ -117,7 +117,7 @@ int cmd_dump(int argc, char *argv[])
 	opt_set(opts, norecovery,	true);
 	opt_set(opts, degraded,		true);
 	opt_set(opts, errors,		BCH_ON_ERROR_continue);
-	opt_set(opts, fix_errors,	FSCK_OPT_NO);
+	opt_set(opts, fix_errors,	FSCK_FIX_no);
 
 	while ((opt = getopt(argc, argv, "o:fjvh")) != -1)
 		switch (opt) {
diff --git a/cmd_fsck.c b/cmd_fsck.c
index 54ace957..00134971 100644
--- a/cmd_fsck.c
+++ b/cmd_fsck.c
@@ -37,7 +37,7 @@ int cmd_fsck(int argc, char *argv[])
 
 	opt_set(opts, degraded, true);
 	opt_set(opts, fsck, true);
-	opt_set(opts, fix_errors, FSCK_OPT_ASK);
+	opt_set(opts, fix_errors, FSCK_FIX_ask);
 
 	while ((opt = getopt_long(argc, argv,
 				  "apynfo:rvh",
@@ -45,14 +45,14 @@ int cmd_fsck(int argc, char *argv[])
 		switch (opt) {
 		case 'a': /* outdated alias for -p */
 		case 'p':
-			opt_set(opts, fix_errors, FSCK_OPT_YES);
+			opt_set(opts, fix_errors, FSCK_FIX_yes);
 			break;
 		case 'y':
-			opt_set(opts, fix_errors, FSCK_OPT_YES);
+			opt_set(opts, fix_errors, FSCK_FIX_no);
 			break;
 		case 'n':
 			opt_set(opts, nochanges, true);
-			opt_set(opts, fix_errors, FSCK_OPT_NO);
+			opt_set(opts, fix_errors, FSCK_FIX_no);
 			break;
 		case 'f':
 			/* force check, even if filesystem marked clean: */
diff --git a/cmd_list_journal.c b/cmd_list_journal.c
index 17124225..ce4caad4 100644
--- a/cmd_list_journal.c
+++ b/cmd_list_journal.c
@@ -234,7 +234,7 @@ int cmd_list_journal(int argc, char *argv[])
 	opt_set(opts, norecovery,	true);
 	opt_set(opts, degraded,		true);
 	opt_set(opts, errors,		BCH_ON_ERROR_continue);
-	opt_set(opts, fix_errors,	FSCK_OPT_YES);
+	opt_set(opts, fix_errors,	FSCK_FIX_yes);
 	opt_set(opts, keep_journal,	true);
 	opt_set(opts, read_journal_only,true);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 9e020775..7d378ab2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -44,6 +44,7 @@ struct user_namespace;
 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
 /* 64bit hashes as llseek() offset (for directories) */
 #define FMODE_64BITHASH         ((__force fmode_t)0x400)
+#define FMODE_BUFFERED		((__force fmode_t)0x800)
 
 struct inode {
 	unsigned long		i_ino;
diff --git a/include/linux/lz4.h b/include/linux/lz4.h
index 86e1dde3..f574964a 100644
--- a/include/linux/lz4.h
+++ b/include/linux/lz4.h
@@ -2,4 +2,9 @@
 
 #define LZ4_compress_destSize(src, dst, srclen, dstlen, workspace)	\
 	LZ4_compress_destSize(src, dst, srclen, dstlen)
+
+#define LZ4_compress_HC(src, dst, srclen, dstlen, level, workspace)	-1
+
 #define LZ4_MEM_COMPRESS 0
+#define LZ4HC_MEM_COMPRESS 0
+#define LZ4HC_MIN_CLEVEL 0
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 3db40cb4..ef032531 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -12,6 +12,7 @@
 #define rcu_access_pointer(p)		READ_ONCE(p)
 
 #define kfree_rcu(ptr, rcu_head)	kfree(ptr) /* XXX */
+#define kvfree_rcu(ptr)			kfree(ptr) /* XXX */
 
 #define RCU_INIT_POINTER(p, v)		WRITE_ONCE(p, v)
 
diff --git a/include/linux/slab.h b/include/linux/slab.h
index a36f6f43..78f906a8 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -213,7 +213,7 @@ static inline struct kmem_cache *kmem_cache_create(size_t obj_size)
 
 #define vfree(p)		free(p)
 
-static inline void *__vmalloc(unsigned long size, gfp_t flags)
+static inline void *__vmalloc_noprof(unsigned long size, gfp_t flags)
 {
 	unsigned i;
 	void *p;
@@ -234,6 +234,7 @@ static inline void *__vmalloc(unsigned long size, gfp_t flags)
 
 	return p;
 }
+#define __vmalloc __vmalloc_noprof
 
 static inline void *vmalloc_exec(unsigned long size, gfp_t gfp_mask)
 {
diff --git a/libbcachefs.c b/libbcachefs.c
index 092a54a6..bac772b2 100644
--- a/libbcachefs.c
+++ b/libbcachefs.c
@@ -604,8 +604,7 @@ struct bch_opts bch2_parse_opts(struct bch_opt_strs strs)
 	u64 v;
 
 	for (i = 0; i < bch2_opts_nr; i++) {
-		if (!strs.by_id[i] ||
-		    bch2_opt_table[i].type == BCH_OPT_FN)
+		if (!strs.by_id[i])
 			continue;
 
 		ret = bch2_opt_parse(NULL,
diff --git a/libbcachefs/bcachefs.h b/libbcachefs/bcachefs.h
index d8c02064..445d010c 100644
--- a/libbcachefs/bcachefs.h
+++ b/libbcachefs/bcachefs.h
@@ -774,9 +774,10 @@ struct bch_fs {
 	struct mutex		sb_lock;
 
 	/* snapshot.c: */
-	GENRADIX(struct snapshot_t) snapshots;
-	struct bch_snapshot_table __rcu *snapshot_table;
+	struct snapshot_table __rcu *snapshots;
+	size_t			snapshot_table_size;
 	struct mutex		snapshot_table_lock;
+
 	struct work_struct	snapshot_delete_work;
 	struct work_struct	snapshot_wait_for_pagecache_and_delete_work;
 	snapshot_id_list	snapshots_unlinked;
diff --git a/libbcachefs/bcachefs_format.h b/libbcachefs/bcachefs_format.h
index 6d693e4d..5c308f84 100644
--- a/libbcachefs/bcachefs_format.h
+++ b/libbcachefs/bcachefs_format.h
@@ -695,7 +695,7 @@ struct bch_reservation {
 /* Maximum size (in u64s) a single pointer could be: */
 #define BKEY_EXTENT_PTR_U64s_MAX\
 	((sizeof(struct bch_extent_crc128) +			\
-	  sizeof(struct bch_extent_ptr)) / sizeof(u64))
+	  sizeof(struct bch_extent_ptr)) / sizeof(__u64))
 
 /* Maximum possible size of an entire extent value: */
 #define BKEY_EXTENT_VAL_U64s_MAX				\
@@ -707,7 +707,7 @@ struct bch_reservation {
 /* Btree pointers don't carry around checksums: */
 #define BKEY_BTREE_PTR_VAL_U64s_MAX				\
 	((sizeof(struct bch_btree_ptr_v2) +			\
-	  sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(u64))
+	  sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(__u64))
 #define BKEY_BTREE_PTR_U64s_MAX					\
 	(BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX)
 
@@ -749,7 +749,7 @@ struct bch_inode_v3 {
 } __packed __aligned(8);
 
 #define INODEv3_FIELDS_START_INITIAL	6
-#define INODEv3_FIELDS_START_CUR	(offsetof(struct bch_inode_v3, fields) / sizeof(u64))
+#define INODEv3_FIELDS_START_CUR	(offsetof(struct bch_inode_v3, fields) / sizeof(__u64))
 
 struct bch_inode_generation {
 	struct bch_val		v;
@@ -916,7 +916,7 @@ struct bch_dirent {
 #define DT_SUBVOL	16
 #define BCH_DT_MAX	17
 
-#define BCH_NAME_MAX	((unsigned) (U8_MAX * sizeof(u64) -		\
+#define BCH_NAME_MAX	((unsigned) (U8_MAX * sizeof(__u64) -		\
 			 sizeof(struct bkey) -				\
 			 offsetof(struct bch_dirent, d_name)))
 
@@ -1009,7 +1009,7 @@ struct bch_alloc_v4 {
 } __packed __aligned(8);
 
 #define BCH_ALLOC_V4_U64s_V0	6
-#define BCH_ALLOC_V4_U64s	(sizeof(struct bch_alloc_v4) / sizeof(u64))
+#define BCH_ALLOC_V4_U64s	(sizeof(struct bch_alloc_v4) / sizeof(__u64))
 
 BITMASK(BCH_ALLOC_V4_NEED_DISCARD,	struct bch_alloc_v4, flags,  0,  1)
 BITMASK(BCH_ALLOC_V4_NEED_INC_GEN,	struct bch_alloc_v4, flags,  1,  2)
@@ -1289,10 +1289,10 @@ struct bch_key {
 };
 
 #define BCH_KEY_MAGIC					\
-	(((u64) 'b' <<  0)|((u64) 'c' <<  8)|		\
-	 ((u64) 'h' << 16)|((u64) '*' << 24)|		\
-	 ((u64) '*' << 32)|((u64) 'k' << 40)|		\
-	 ((u64) 'e' << 48)|((u64) 'y' << 56))
+	(((__u64) 'b' <<  0)|((__u64) 'c' <<  8)|		\
+	 ((__u64) 'h' << 16)|((__u64) '*' << 24)|		\
+	 ((__u64) '*' << 32)|((__u64) 'k' << 40)|		\
+	 ((__u64) 'e' << 48)|((__u64) 'y' << 56))
 
 struct bch_encrypted_key {
 	__le64			magic;
@@ -1747,7 +1747,7 @@ LE64_BITMASK(BCH_SB_HAS_TOPOLOGY_ERRORS,struct bch_sb, flags[0], 61, 62);
 LE64_BITMASK(BCH_SB_BIG_ENDIAN,		struct bch_sb, flags[0], 62, 63);
 
 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,	struct bch_sb, flags[1],  0,  4);
-LE64_BITMASK(BCH_SB_COMPRESSION_TYPE,	struct bch_sb, flags[1],  4,  8);
+LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_LO,struct bch_sb, flags[1],  4,  8);
 LE64_BITMASK(BCH_SB_INODE_32BIT,	struct bch_sb, flags[1],  8,  9);
 
 LE64_BITMASK(BCH_SB_128_BIT_MACS,	struct bch_sb, flags[1],  9, 10);
@@ -1767,7 +1767,7 @@ LE64_BITMASK(BCH_SB_PROMOTE_TARGET,	struct bch_sb, flags[1], 28, 40);
 LE64_BITMASK(BCH_SB_FOREGROUND_TARGET,	struct bch_sb, flags[1], 40, 52);
 LE64_BITMASK(BCH_SB_BACKGROUND_TARGET,	struct bch_sb, flags[1], 52, 64);
 
-LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE,
+LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO,
 					struct bch_sb, flags[2],  0,  4);
 LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,	struct bch_sb, flags[2],  4, 64);
 
@@ -1783,11 +1783,36 @@ LE64_BITMASK(BCH_SB_NOCOW,		struct bch_sb, flags[4], 33, 34);
 LE64_BITMASK(BCH_SB_WRITE_BUFFER_SIZE,	struct bch_sb, flags[4], 34, 54);
 LE64_BITMASK(BCH_SB_VERSION_UPGRADE,	struct bch_sb, flags[4], 54, 56);
 
-/* flags[4] 56-64 unused: */
+LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_HI,struct bch_sb, flags[4], 56, 60);
+LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI,
+					struct bch_sb, flags[4], 60, 64);
 
 LE64_BITMASK(BCH_SB_VERSION_UPGRADE_COMPLETE,
 					struct bch_sb, flags[5],  0, 16);
 
+static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
+{
+	return BCH_SB_COMPRESSION_TYPE_LO(sb) | (BCH_SB_COMPRESSION_TYPE_HI(sb) << 4);
+}
+
+static inline void SET_BCH_SB_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
+{
+	SET_BCH_SB_COMPRESSION_TYPE_LO(sb, v);
+	SET_BCH_SB_COMPRESSION_TYPE_HI(sb, v >> 4);
+}
+
+static inline __u64 BCH_SB_BACKGROUND_COMPRESSION_TYPE(const struct bch_sb *sb)
+{
+	return BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb) |
+		(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb) << 4);
+}
+
+static inline void SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
+{
+	SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb, v);
+	SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb, v >> 4);
+}
+
 /*
  * Features:
  *
@@ -2272,7 +2297,7 @@ static inline __u64 BTREE_NODE_ID(struct btree_node *n)
 	return BTREE_NODE_ID_LO(n) | (BTREE_NODE_ID_HI(n) << 4);
 }
 
-static inline void SET_BTREE_NODE_ID(struct btree_node *n, u64 v)
+static inline void SET_BTREE_NODE_ID(struct btree_node *n, __u64 v)
 {
 	SET_BTREE_NODE_ID_LO(n, v);
 	SET_BTREE_NODE_ID_HI(n, v >> 4);
diff --git a/libbcachefs/btree_gc.c b/libbcachefs/btree_gc.c
index c47d5d8c..be537b23 100644
--- a/libbcachefs/btree_gc.c
+++ b/libbcachefs/btree_gc.c
@@ -1811,7 +1811,7 @@ again:
 	if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG) ||
 	    (BCH_SB_HAS_TOPOLOGY_ERRORS(c->disk_sb.sb) &&
 	     c->curr_recovery_pass <= BCH_RECOVERY_PASS_check_allocations &&
-	     c->opts.fix_errors != FSCK_OPT_NO)) {
+	     c->opts.fix_errors != FSCK_FIX_no)) {
 		bch_info(c, "Starting topology repair pass");
 		ret = bch2_repair_topology(c);
 		if (ret)
diff --git a/libbcachefs/btree_update_leaf.c b/libbcachefs/btree_update_leaf.c
index 53219fdc..3638cef2 100644
--- a/libbcachefs/btree_update_leaf.c
+++ b/libbcachefs/btree_update_leaf.c
@@ -311,7 +311,7 @@ static inline void btree_insert_entry_checks(struct btree_trans *trans,
 		!(i->flags & BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) &&
 		test_bit(JOURNAL_REPLAY_DONE, &trans->c->journal.flags) &&
 		i->k->k.p.snapshot &&
-		bch2_snapshot_internal_node(trans->c, i->k->k.p.snapshot));
+		bch2_snapshot_is_internal_node(trans->c, i->k->k.p.snapshot));
 }
 
 static noinline int
@@ -1229,7 +1229,7 @@ static inline int check_pos_snapshot_overwritten(struct btree_trans *trans,
 					  struct bpos pos)
 {
 	if (!btree_type_has_snapshots(id) ||
-	    !snapshot_t(trans->c, pos.snapshot)->children[0])
+	    bch2_snapshot_is_leaf(trans->c, pos.snapshot))
 		return 0;
 
 	return __check_pos_snapshot_overwritten(trans, id, pos);
diff --git a/libbcachefs/btree_write_buffer.c b/libbcachefs/btree_write_buffer.c
index b5022631..6c30a72e 100644
--- a/libbcachefs/btree_write_buffer.c
+++ b/libbcachefs/btree_write_buffer.c
@@ -129,6 +129,9 @@ int __bch2_btree_write_buffer_flush(struct btree_trans *trans, unsigned commit_f
 	keys = wb->keys[s.idx];
 	nr = s.nr;
 
+	if (race_fault())
+		goto slowpath;
+
 	/*
 	 * We first sort so that we can detect and skip redundant updates, and
 	 * then we attempt to flush in sorted btree order, as this is most
diff --git a/libbcachefs/checksum.h b/libbcachefs/checksum.h
index 409ad534..1ad1d5f0 100644
--- a/libbcachefs/checksum.h
+++ b/libbcachefs/checksum.h
@@ -120,12 +120,6 @@ static inline enum bch_csum_type bch2_meta_checksum_type(struct bch_fs *c)
 	return bch2_csum_opt_to_type(c->opts.metadata_checksum, false);
 }
 
-static const unsigned bch2_compression_opt_to_type[] = {
-#define x(t, n) [BCH_COMPRESSION_OPT_##t] = BCH_COMPRESSION_TYPE_##t,
-	BCH_COMPRESSION_OPTS()
-#undef x
-};
-
 static inline bool bch2_checksum_type_valid(const struct bch_fs *c,
 					   unsigned type)
 {
diff --git a/libbcachefs/compress.c b/libbcachefs/compress.c
index 48427a27..560214c1 100644
--- a/libbcachefs/compress.c
+++ b/libbcachefs/compress.c
@@ -296,21 +296,32 @@ static int attempt_compress(struct bch_fs *c,
 			    void *workspace,
 			    void *dst, size_t dst_len,
 			    void *src, size_t src_len,
-			    enum bch_compression_type compression_type)
+			    struct bch_compression_opt compression)
 {
-	switch (compression_type) {
-	case BCH_COMPRESSION_TYPE_lz4: {
-		int len = src_len;
-		int ret = LZ4_compress_destSize(
-				src,		dst,
-				&len,		dst_len,
-				workspace);
-
-		if (len < src_len)
-			return -len;
+	enum bch_compression_type compression_type =
+		__bch2_compression_opt_to_type[compression.type];
 
-		return ret;
-	}
+	switch (compression_type) {
+	case BCH_COMPRESSION_TYPE_lz4:
+		if (compression.level < LZ4HC_MIN_CLEVEL) {
+			int len = src_len;
+			int ret = LZ4_compress_destSize(
+					src,		dst,
+					&len,		dst_len,
+					workspace);
+			if (len < src_len)
+				return -len;
+
+			return ret;
+		} else {
+			int ret = LZ4_compress_HC(
+					src,		dst,
+					src_len,	dst_len,
+					compression.level,
+					workspace);
+
+			return ret ?: -1;
+		}
 	case BCH_COMPRESSION_TYPE_gzip: {
 		z_stream strm = {
 			.next_in	= src,
@@ -320,7 +331,11 @@ static int attempt_compress(struct bch_fs *c,
 		};
 
 		zlib_set_workspace(&strm, workspace);
-		zlib_deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
+		zlib_deflateInit2(&strm,
+				  compression.level
+				  ? clamp_t(unsigned, compression.level,
+					    Z_BEST_SPEED, Z_BEST_COMPRESSION)
+				  : Z_DEFAULT_COMPRESSION,
 				  Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL,
 				  Z_DEFAULT_STRATEGY);
 
@@ -333,8 +348,14 @@ static int attempt_compress(struct bch_fs *c,
 		return strm.total_out;
 	}
 	case BCH_COMPRESSION_TYPE_zstd: {
+		/*
+		 * rescale:
+		 * zstd max compression level is 22, our max level is 15
+		 */
+		unsigned level = min((compression.level * 3) / 2, zstd_max_clevel());
+		ZSTD_parameters params = zstd_get_params(level, c->opts.encoded_extent_max);
 		ZSTD_CCtx *ctx = zstd_init_cctx(workspace,
-			zstd_cctx_workspace_bound(&c->zstd_params.cParams));
+			zstd_cctx_workspace_bound(&params.cParams));
 
 		/*
 		 * ZSTD requires that when we decompress we pass in the exact
@@ -365,10 +386,12 @@ static int attempt_compress(struct bch_fs *c,
 static unsigned __bio_compress(struct bch_fs *c,
 			       struct bio *dst, size_t *dst_len,
 			       struct bio *src, size_t *src_len,
-			       enum bch_compression_type compression_type)
+			       struct bch_compression_opt compression)
 {
 	struct bbuf src_data = { NULL }, dst_data = { NULL };
 	void *workspace;
+	enum bch_compression_type compression_type =
+		__bch2_compression_opt_to_type[compression.type];
 	unsigned pad;
 	int ret = 0;
 
@@ -400,7 +423,7 @@ static unsigned __bio_compress(struct bch_fs *c,
 		ret = attempt_compress(c, workspace,
 				       dst_data.b,	*dst_len,
 				       src_data.b,	*src_len,
-				       compression_type);
+				       compression);
 		if (ret > 0) {
 			*dst_len = ret;
 			ret = 0;
@@ -447,22 +470,24 @@ static unsigned __bio_compress(struct bch_fs *c,
 	BUG_ON(!*src_len || *src_len > src->bi_iter.bi_size);
 	BUG_ON(*dst_len & (block_bytes(c) - 1));
 	BUG_ON(*src_len & (block_bytes(c) - 1));
+	ret = compression_type;
 out:
 	bio_unmap_or_unbounce(c, src_data);
 	bio_unmap_or_unbounce(c, dst_data);
-	return compression_type;
+	return ret;
 err:
-	compression_type = BCH_COMPRESSION_TYPE_incompressible;
+	ret = BCH_COMPRESSION_TYPE_incompressible;
 	goto out;
 }
 
 unsigned bch2_bio_compress(struct bch_fs *c,
 			   struct bio *dst, size_t *dst_len,
 			   struct bio *src, size_t *src_len,
-			   unsigned compression_type)
+			   unsigned compression_opt)
 {
 	unsigned orig_dst = dst->bi_iter.bi_size;
 	unsigned orig_src = src->bi_iter.bi_size;
+	unsigned compression_type;
 
 	/* Don't consume more than BCH_ENCODED_EXTENT_MAX from @src: */
 	src->bi_iter.bi_size = min_t(unsigned, src->bi_iter.bi_size,
@@ -470,11 +495,9 @@ unsigned bch2_bio_compress(struct bch_fs *c,
 	/* Don't generate a bigger output than input: */
 	dst->bi_iter.bi_size = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
 
-	if (compression_type == BCH_COMPRESSION_TYPE_lz4_old)
-		compression_type = BCH_COMPRESSION_TYPE_lz4;
-
 	compression_type =
-		__bio_compress(c, dst, dst_len, src, src_len, compression_type);
+		__bio_compress(c, dst, dst_len, src, src_len,
+			       bch2_compression_decode(compression_opt));
 
 	dst->bi_iter.bi_size = orig_dst;
 	src->bi_iter.bi_size = orig_src;
@@ -521,8 +544,10 @@ static int __bch2_check_set_has_compressed_data(struct bch_fs *c, u64 f)
 }
 
 int bch2_check_set_has_compressed_data(struct bch_fs *c,
-				       unsigned compression_type)
+				       unsigned compression_opt)
 {
+	unsigned compression_type = bch2_compression_decode(compression_opt).type;
+
 	BUG_ON(compression_type >= ARRAY_SIZE(bch2_compression_opt_to_feature));
 
 	return compression_type
@@ -546,14 +571,16 @@ static int __bch2_fs_compress_init(struct bch_fs *c, u64 features)
 {
 	size_t decompress_workspace_size = 0;
 	bool decompress_workspace_needed;
-	ZSTD_parameters params = zstd_get_params(0, c->opts.encoded_extent_max);
+	ZSTD_parameters params = zstd_get_params(zstd_max_clevel(),
+						 c->opts.encoded_extent_max);
 	struct {
-		unsigned	feature;
-		unsigned	type;
-		size_t		compress_workspace;
-		size_t		decompress_workspace;
+		unsigned			feature;
+		enum bch_compression_type	type;
+		size_t				compress_workspace;
+		size_t				decompress_workspace;
 	} compression_types[] = {
-		{ BCH_FEATURE_lz4, BCH_COMPRESSION_TYPE_lz4, LZ4_MEM_COMPRESS, 0 },
+		{ BCH_FEATURE_lz4, BCH_COMPRESSION_TYPE_lz4,
+			max_t(size_t, LZ4_MEM_COMPRESS, LZ4HC_MEM_COMPRESS) },
 		{ BCH_FEATURE_gzip, BCH_COMPRESSION_TYPE_gzip,
 			zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL),
 			zlib_inflate_workspacesize(), },
@@ -612,16 +639,74 @@ static int __bch2_fs_compress_init(struct bch_fs *c, u64 features)
 	return 0;
 }
 
+static u64 compression_opt_to_feature(unsigned v)
+{
+	unsigned type = bch2_compression_decode(v).type;
+	return 1ULL << bch2_compression_opt_to_feature[type];
+}
+
 int bch2_fs_compress_init(struct bch_fs *c)
 {
 	u64 f = c->sb.features;
 
-	if (c->opts.compression)
-		f |= 1ULL << bch2_compression_opt_to_feature[c->opts.compression];
-
-	if (c->opts.background_compression)
-		f |= 1ULL << bch2_compression_opt_to_feature[c->opts.background_compression];
+	f |= compression_opt_to_feature(c->opts.compression);
+	f |= compression_opt_to_feature(c->opts.background_compression);
 
 	return __bch2_fs_compress_init(c, f);
+}
+
+int bch2_opt_compression_parse(struct bch_fs *c, const char *_val, u64 *res,
+			       struct printbuf *err)
+{
+	char *val = kstrdup(_val, GFP_KERNEL);
+	char *p = val, *type_str, *level_str;
+	struct bch_compression_opt opt = { 0 };
+	int ret;
+
+	if (!val)
+		return -ENOMEM;
+
+	type_str = strsep(&p, ":");
+	level_str = p;
+
+	ret = match_string(bch2_compression_opts, -1, type_str);
+	if (ret < 0 && err)
+		prt_str(err, "invalid compression type");
+	if (ret < 0)
+		goto err;
+
+	opt.type = ret;
+
+	if (level_str) {
+		unsigned level;
+
+		ret = kstrtouint(level_str, 10, &level);
+		if (!ret && !opt.type && level)
+			ret = -EINVAL;
+		if (!ret && level > 15)
+			ret = -EINVAL;
+		if (ret < 0 && err)
+			prt_str(err, "invalid compression level");
+		if (ret < 0)
+			goto err;
+
+		opt.level = level;
+	}
+
+	*res = bch2_compression_encode(opt);
+err:
+	kfree(val);
+	return ret;
+}
+
+void bch2_opt_compression_to_text(struct printbuf *out,
+				  struct bch_fs *c,
+				  struct bch_sb *sb,
+				  u64 v)
+{
+	struct bch_compression_opt opt = bch2_compression_decode(v);
 
+	prt_str(out, bch2_compression_opts[opt.type]);
+	if (opt.level)
+		prt_printf(out, ":%u", opt.level);
 }
diff --git a/libbcachefs/compress.h b/libbcachefs/compress.h
index 4bab1f61..052ea303 100644
--- a/libbcachefs/compress.h
+++ b/libbcachefs/compress.h
@@ -4,6 +4,35 @@
 
 #include "extents_types.h"
 
+struct bch_compression_opt {
+	u8		type:4,
+			level:4;
+};
+
+static inline struct bch_compression_opt bch2_compression_decode(unsigned v)
+{
+	return (struct bch_compression_opt) {
+		.type	= v & 15,
+		.level	= v >> 4,
+	};
+}
+
+static inline unsigned bch2_compression_encode(struct bch_compression_opt opt)
+{
+	return opt.type|(opt.level << 4);
+}
+
+static const unsigned __bch2_compression_opt_to_type[] = {
+#define x(t, n) [BCH_COMPRESSION_OPT_##t] = BCH_COMPRESSION_TYPE_##t,
+	BCH_COMPRESSION_OPTS()
+#undef x
+};
+
+static inline enum bch_compression_type bch2_compression_opt_to_type(unsigned v)
+{
+	return __bch2_compression_opt_to_type[bch2_compression_decode(v).type];
+}
+
 int bch2_bio_uncompress_inplace(struct bch_fs *, struct bio *,
 				struct bch_extent_crc_unpacked *);
 int bch2_bio_uncompress(struct bch_fs *, struct bio *, struct bio *,
@@ -15,4 +44,12 @@ int bch2_check_set_has_compressed_data(struct bch_fs *, unsigned);
 void bch2_fs_compress_exit(struct bch_fs *);
 int bch2_fs_compress_init(struct bch_fs *);
 
+int bch2_opt_compression_parse(struct bch_fs *, const char *, u64 *, struct printbuf *);
+void bch2_opt_compression_to_text(struct printbuf *, struct bch_fs *, struct bch_sb *, u64);
+
+#define bch2_opt_compression (struct bch_opt_fn) {		\
+	.parse		= bch2_opt_compression_parse,	\
+	.to_text	= bch2_opt_compression_to_text,	\
+}
+
 #endif /* _BCACHEFS_COMPRESS_H */
diff --git a/libbcachefs/data_update.c b/libbcachefs/data_update.c
index 3c918368..cfc62446 100644
--- a/libbcachefs/data_update.c
+++ b/libbcachefs/data_update.c
@@ -455,9 +455,7 @@ int bch2_data_update_init(struct btree_trans *trans,
 		BCH_WRITE_DATA_ENCODED|
 		BCH_WRITE_MOVE|
 		m->data_opts.write_flags;
-	m->op.compression_type =
-		bch2_compression_opt_to_type[io_opts.background_compression ?:
-					     io_opts.compression];
+	m->op.compression_opt	= io_opts.background_compression ?: io_opts.compression;
 	m->op.watermark		= m->data_opts.btree_insert_flags & BCH_WATERMARK_MASK;
 
 	bkey_for_each_ptr(ptrs, ptr)
diff --git a/libbcachefs/disk_groups.c b/libbcachefs/disk_groups.c
index 52b64007..de14ca3a 100644
--- a/libbcachefs/disk_groups.c
+++ b/libbcachefs/disk_groups.c
@@ -460,30 +460,37 @@ int bch2_dev_group_set(struct bch_fs *c, struct bch_dev *ca, const char *name)
 	return ret;
 }
 
-int bch2_opt_target_parse(struct bch_fs *c, const char *buf, u64 *v)
+int bch2_opt_target_parse(struct bch_fs *c, const char *val, u64 *res,
+			  struct printbuf *err)
 {
 	struct bch_dev *ca;
 	int g;
 
-	if (!strlen(buf) || !strcmp(buf, "none")) {
-		*v = 0;
+	if (!val)
+		return -EINVAL;
+
+	if (!c)
+		return 0;
+
+	if (!strlen(val) || !strcmp(val, "none")) {
+		*res = 0;
 		return 0;
 	}
 
 	/* Is it a device? */
-	ca = bch2_dev_lookup(c, buf);
+	ca = bch2_dev_lookup(c, val);
 	if (!IS_ERR(ca)) {
-		*v = dev_to_target(ca->dev_idx);
+		*res = dev_to_target(ca->dev_idx);
 		percpu_ref_put(&ca->ref);
 		return 0;
 	}
 
 	mutex_lock(&c->sb_lock);
-	g = bch2_disk_path_find(&c->disk_sb, buf);
+	g = bch2_disk_path_find(&c->disk_sb, val);
 	mutex_unlock(&c->sb_lock);
 
 	if (g >= 0) {
-		*v = group_to_target(g);
+		*res = group_to_target(g);
 		return 0;
 	}
 
diff --git a/libbcachefs/disk_groups.h b/libbcachefs/disk_groups.h
index ec12584c..bd771176 100644
--- a/libbcachefs/disk_groups.h
+++ b/libbcachefs/disk_groups.h
@@ -85,9 +85,14 @@ int bch2_disk_path_find_or_create(struct bch_sb_handle *, const char *);
 
 void bch2_disk_path_to_text(struct printbuf *, struct bch_sb *, unsigned);
 
-int bch2_opt_target_parse(struct bch_fs *, const char *, u64 *);
+int bch2_opt_target_parse(struct bch_fs *, const char *, u64 *, struct printbuf *);
 void bch2_opt_target_to_text(struct printbuf *, struct bch_fs *, struct bch_sb *, u64);
 
+#define bch2_opt_target (struct bch_opt_fn) {		\
+	.parse		= bch2_opt_target_parse,	\
+	.to_text	= bch2_opt_target_to_text,	\
+}
+
 int bch2_sb_disk_groups_to_cpu(struct bch_fs *);
 
 int __bch2_dev_group_set(struct bch_fs *, struct bch_dev *, const char *);
diff --git a/libbcachefs/error.c b/libbcachefs/error.c
index b08cd23d..685464b8 100644
--- a/libbcachefs/error.c
+++ b/libbcachefs/error.c
@@ -204,7 +204,7 @@ int bch2_fsck_err(struct bch_fs *c, unsigned flags, const char *fmt, ...)
 			prt_str(out, ", continuing");
 			ret = -BCH_ERR_fsck_ignore;
 		}
-	} else if (c->opts.fix_errors == FSCK_OPT_EXIT) {
+	} else if (c->opts.fix_errors == FSCK_FIX_exit) {
 		prt_str(out, ", exiting");
 		ret = -BCH_ERR_fsck_errors_not_fixed;
 	} else if (flags & FSCK_CAN_FIX) {
@@ -212,7 +212,7 @@ int bch2_fsck_err(struct bch_fs *c, unsigned flags, const char *fmt, ...)
 			? s->fix
 			: c->opts.fix_errors;
 
-		if (fix == FSCK_OPT_ASK) {
+		if (fix == FSCK_FIX_ask) {
 			int ask;
 
 			prt_str(out, ": fix?");
@@ -223,13 +223,13 @@ int bch2_fsck_err(struct bch_fs *c, unsigned flags, const char *fmt, ...)
 
 			if (ask >= YN_ALLNO && s)
 				s->fix = ask == YN_ALLNO
-					? FSCK_OPT_NO
-					: FSCK_OPT_YES;
+					? FSCK_FIX_no
+					: FSCK_FIX_yes;
 
 			ret = ask & 1
 				? -BCH_ERR_fsck_fix
 				: -BCH_ERR_fsck_ignore;
-		} else if (fix == FSCK_OPT_YES ||
+		} else if (fix == FSCK_FIX_yes ||
 			   (c->opts.nochanges &&
 			    !(flags & FSCK_CAN_IGNORE))) {
 			prt_str(out, ", fixing");
@@ -244,7 +244,7 @@ int bch2_fsck_err(struct bch_fs *c, unsigned flags, const char *fmt, ...)
 	}
 
 	if (ret == -BCH_ERR_fsck_ignore &&
-	    (c->opts.fix_errors == FSCK_OPT_EXIT ||
+	    (c->opts.fix_errors == FSCK_FIX_exit ||
 	     !(flags & FSCK_CAN_IGNORE)))
 		ret = -BCH_ERR_fsck_errors_not_fixed;
 
diff --git a/libbcachefs/error.h b/libbcachefs/error.h
index edf12443..7ce95400 100644
--- a/libbcachefs/error.h
+++ b/libbcachefs/error.h
@@ -91,13 +91,6 @@ do {									\
  * be able to repair:
  */
 
-enum fsck_err_opts {
-	FSCK_OPT_EXIT,
-	FSCK_OPT_YES,
-	FSCK_OPT_NO,
-	FSCK_OPT_ASK,
-};
-
 struct fsck_err_state {
 	struct list_head	list;
 	const char		*fmt;
diff --git a/libbcachefs/fs-io.c b/libbcachefs/fs-io.c
index a8060052..6b691b2b 100644
--- a/libbcachefs/fs-io.c
+++ b/libbcachefs/fs-io.c
@@ -35,6 +35,8 @@
 
 #include <trace/events/writeback.h>
 
+static void bch2_clamp_data_hole(struct inode *, u64 *, u64 *, unsigned);
+
 struct folio_vec {
 	struct folio	*fv_folio;
 	size_t		fv_offset;
@@ -1972,7 +1974,7 @@ static int __bch2_buffered_write(struct bch_inode_info *inode,
 	darray_for_each(folios, fi) {
 		struct folio *f = *fi;
 		u64 f_len = min(end, folio_end_pos(f)) - f_pos;
-		unsigned f_copied = copy_folio_from_iter_atomic(f, f_offset, f_len, iter);
+		unsigned f_copied = copy_page_from_iter_atomic(&f->page, f_offset, f_len, iter);
 
 		if (!f_copied) {
 			folios_trunc(&folios, fi);
@@ -3373,6 +3375,8 @@ static int __bchfs_fallocate(struct bch_inode_info *inode, int mode,
 		struct quota_res quota_res = { 0 };
 		struct bkey_s_c k;
 		unsigned sectors;
+		bool is_allocation;
+		u64 hole_start, hole_end;
 		u32 snapshot;
 
 		bch2_trans_begin(&trans);
@@ -3388,6 +3392,10 @@ static int __bchfs_fallocate(struct bch_inode_info *inode, int mode,
 		if ((ret = bkey_err(k)))
 			goto bkey_err;
 
+		hole_start	= iter.pos.offset;
+		hole_end	= bpos_min(k.k->p, end_pos).offset;
+		is_allocation	= bkey_extent_is_allocation(k.k);
+
 		/* already reserved */
 		if (bkey_extent_is_reservation(k) &&
 		    bch2_bkey_nr_ptrs_fully_allocated(k) >= opts.data_replicas) {
@@ -3401,17 +3409,26 @@ static int __bchfs_fallocate(struct bch_inode_info *inode, int mode,
 			continue;
 		}
 
-		/*
-		 * XXX: for nocow mode, we should promote shared extents to
-		 * unshared here
-		 */
+		if (!(mode & FALLOC_FL_ZERO_RANGE)) {
+			ret = drop_locks_do(&trans,
+				(bch2_clamp_data_hole(&inode->v,
+						      &hole_start,
+						      &hole_end,
+						      opts.data_replicas), 0));
+			bch2_btree_iter_set_pos(&iter, POS(iter.pos.inode, hole_start));
+
+			if (ret)
+				goto bkey_err;
+
+			if (hole_start == hole_end)
+				continue;
+		}
 
-		sectors = bpos_min(k.k->p, end_pos).offset - iter.pos.offset;
+		sectors	= hole_end - hole_start;
 
-		if (!bkey_extent_is_allocation(k.k)) {
+		if (!is_allocation) {
 			ret = bch2_quota_reservation_add(c, inode,
-					&quota_res,
-					sectors, true);
+					&quota_res, sectors, true);
 			if (unlikely(ret))
 				goto bkey_err;
 		}
@@ -3423,15 +3440,15 @@ static int __bchfs_fallocate(struct bch_inode_info *inode, int mode,
 			goto bkey_err;
 
 		i_sectors_acct(c, inode, &quota_res, i_sectors_delta);
+
+		drop_locks_do(&trans,
+			(mark_pagecache_reserved(inode, hole_start, iter.pos.offset), 0));
 bkey_err:
 		bch2_quota_reservation_put(c, inode, &quota_res);
 		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 			ret = 0;
 	}
 
-	bch2_trans_unlock(&trans); /* lock ordering, before taking pagecache locks: */
-	mark_pagecache_reserved(inode, start_sector, iter.pos.offset);
-
 	if (bch2_err_matches(ret, ENOSPC) && (mode & FALLOC_FL_ZERO_RANGE)) {
 		struct quota_res quota_res = { 0 };
 		s64 i_sectors_delta = 0;
@@ -3679,14 +3696,16 @@ err:
 
 /* fseek: */
 
-static int folio_data_offset(struct folio *folio, loff_t pos)
+static int folio_data_offset(struct folio *folio, loff_t pos,
+			     unsigned min_replicas)
 {
 	struct bch_folio *s = bch2_folio(folio);
 	unsigned i, sectors = folio_sectors(folio);
 
 	if (s)
 		for (i = folio_pos_to_s(folio, pos); i < sectors; i++)
-			if (s->s[i].state >= SECTOR_dirty)
+			if (s->s[i].state >= SECTOR_dirty &&
+			    s->s[i].nr_replicas + s->s[i].replicas_reserved >= min_replicas)
 				return i << SECTOR_SHIFT;
 
 	return -1;
@@ -3694,7 +3713,8 @@ static int folio_data_offset(struct folio *folio, loff_t pos)
 
 static loff_t bch2_seek_pagecache_data(struct inode *vinode,
 				       loff_t start_offset,
-				       loff_t end_offset)
+				       loff_t end_offset,
+				       unsigned min_replicas)
 {
 	struct folio_batch fbatch;
 	pgoff_t start_index	= start_offset >> PAGE_SHIFT;
@@ -3713,7 +3733,8 @@ static loff_t bch2_seek_pagecache_data(struct inode *vinode,
 
 			folio_lock(folio);
 			offset = folio_data_offset(folio,
-					max(folio_pos(folio), start_offset));
+					max(folio_pos(folio), start_offset),
+					min_replicas);
 			if (offset >= 0) {
 				ret = clamp(folio_pos(folio) + offset,
 					    start_offset, end_offset);
@@ -3775,7 +3796,7 @@ err:
 
 	if (next_data > offset)
 		next_data = bch2_seek_pagecache_data(&inode->v,
-						     offset, next_data);
+						     offset, next_data, 0);
 
 	if (next_data >= isize)
 		return -ENXIO;
@@ -3783,7 +3804,8 @@ err:
 	return vfs_setpos(file, next_data, MAX_LFS_FILESIZE);
 }
 
-static bool folio_hole_offset(struct address_space *mapping, loff_t *offset)
+static bool folio_hole_offset(struct address_space *mapping, loff_t *offset,
+			      unsigned min_replicas)
 {
 	struct folio *folio;
 	struct bch_folio *s;
@@ -3800,7 +3822,8 @@ static bool folio_hole_offset(struct address_space *mapping, loff_t *offset)
 
 	sectors = folio_sectors(folio);
 	for (i = folio_pos_to_s(folio, *offset); i < sectors; i++)
-		if (s->s[i].state < SECTOR_dirty) {
+		if (s->s[i].state < SECTOR_dirty ||
+		    s->s[i].nr_replicas + s->s[i].replicas_reserved < min_replicas) {
 			*offset = max(*offset,
 				      folio_pos(folio) + (i << SECTOR_SHIFT));
 			goto unlock;
@@ -3815,18 +3838,34 @@ unlock:
 
 static loff_t bch2_seek_pagecache_hole(struct inode *vinode,
 				       loff_t start_offset,
-				       loff_t end_offset)
+				       loff_t end_offset,
+				       unsigned min_replicas)
 {
 	struct address_space *mapping = vinode->i_mapping;
 	loff_t offset = start_offset;
 
 	while (offset < end_offset &&
-	       !folio_hole_offset(mapping, &offset))
+	       !folio_hole_offset(mapping, &offset, min_replicas))
 		;
 
 	return min(offset, end_offset);
 }
 
+static void bch2_clamp_data_hole(struct inode *inode,
+				 u64 *hole_start,
+				 u64 *hole_end,
+				 unsigned min_replicas)
+{
+	*hole_start = bch2_seek_pagecache_hole(inode,
+		*hole_start << 9, *hole_end << 9, min_replicas) >> 9;
+
+	if (*hole_start == *hole_end)
+		return;
+
+	*hole_end = bch2_seek_pagecache_data(inode,
+		*hole_start << 9, *hole_end << 9, min_replicas) >> 9;
+}
+
 static loff_t bch2_seek_hole(struct file *file, u64 offset)
 {
 	struct bch_inode_info *inode = file_bch_inode(file);
@@ -3856,12 +3895,12 @@ retry:
 			   BTREE_ITER_SLOTS, k, ret) {
 		if (k.k->p.inode != inode->v.i_ino) {
 			next_hole = bch2_seek_pagecache_hole(&inode->v,
-					offset, MAX_LFS_FILESIZE);
+					offset, MAX_LFS_FILESIZE, 0);
 			break;
 		} else if (!bkey_extent_is_data(k.k)) {
 			next_hole = bch2_seek_pagecache_hole(&inode->v,
 					max(offset, bkey_start_offset(k.k) << 9),
-					k.k->p.offset << 9);
+					k.k->p.offset << 9, 0);
 
 			if (next_hole < k.k->p.offset << 9)
 				break;
diff --git a/libbcachefs/fsck.c b/libbcachefs/fsck.c
index ddc2782f..7edd4632 100644
--- a/libbcachefs/fsck.c
+++ b/libbcachefs/fsck.c
@@ -894,7 +894,7 @@ static int check_inode(struct btree_trans *trans,
 	 * particular is not atomic, so on the internal snapshot nodes
 	 * we can see inodes marked for deletion after a clean shutdown
 	 */
-	if (bch2_snapshot_internal_node(c, k.k->p.snapshot))
+	if (bch2_snapshot_is_internal_node(c, k.k->p.snapshot))
 		return 0;
 
 	if (!bkey_is_inode(k.k))
@@ -2122,6 +2122,8 @@ int bch2_check_directory_structure(struct bch_fs *c)
 	return ret;
 }
 
+/* check_nlink pass: */
+
 struct nlink_table {
 	size_t		nr;
 	size_t		size;
diff --git a/libbcachefs/io.c b/libbcachefs/io.c
index 33762e4a..8604df80 100644
--- a/libbcachefs/io.c
+++ b/libbcachefs/io.c
@@ -1078,7 +1078,7 @@ static enum prep_encoded_ret {
 	/* Can we just write the entire extent as is? */
 	if (op->crc.uncompressed_size == op->crc.live_size &&
 	    op->crc.compressed_size <= wp->sectors_free &&
-	    (op->crc.compression_type == op->compression_type ||
+	    (op->crc.compression_type == bch2_compression_opt_to_type(op->compression_opt) ||
 	     op->incompressible)) {
 		if (!crc_is_compressed(op->crc) &&
 		    op->csum_type != op->crc.csum_type &&
@@ -1126,7 +1126,7 @@ static enum prep_encoded_ret {
 	/*
 	 * If we want to compress the data, it has to be decrypted:
 	 */
-	if ((op->compression_type ||
+	if ((op->compression_opt ||
 	     bch2_csum_type_is_encryption(op->crc.csum_type) !=
 	     bch2_csum_type_is_encryption(op->csum_type)) &&
 	    bch2_write_decrypt(op))
@@ -1173,7 +1173,7 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 	}
 
 	if (ec_buf ||
-	    op->compression_type ||
+	    op->compression_opt ||
 	    (op->csum_type &&
 	     !(op->flags & BCH_WRITE_PAGES_STABLE)) ||
 	    (bch2_csum_type_is_encryption(op->csum_type) &&
@@ -1196,16 +1196,16 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 		    dst->bi_iter.bi_size < c->opts.encoded_extent_max)
 			break;
 
-		BUG_ON(op->compression_type &&
+		BUG_ON(op->compression_opt &&
 		       (op->flags & BCH_WRITE_DATA_ENCODED) &&
 		       bch2_csum_type_is_encryption(op->crc.csum_type));
-		BUG_ON(op->compression_type && !bounce);
+		BUG_ON(op->compression_opt && !bounce);
 
 		crc.compression_type = op->incompressible
 			? BCH_COMPRESSION_TYPE_incompressible
-			: op->compression_type
+			: op->compression_opt
 			? bch2_bio_compress(c, dst, &dst_len, src, &src_len,
-					    op->compression_type)
+					    op->compression_opt)
 			: 0;
 		if (!crc_is_compressed(crc)) {
 			dst_len = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
diff --git a/libbcachefs/io.h b/libbcachefs/io.h
index 7a243a5f..1476380d 100644
--- a/libbcachefs/io.h
+++ b/libbcachefs/io.h
@@ -86,7 +86,7 @@ static inline void bch2_write_op_init(struct bch_write_op *op, struct bch_fs *c,
 	op->written		= 0;
 	op->error		= 0;
 	op->csum_type		= bch2_data_checksum_type(c, opts);
-	op->compression_type	= bch2_compression_opt_to_type[opts.compression];
+	op->compression_opt	= opts.compression;
 	op->nr_replicas		= 0;
 	op->nr_replicas_required = c->opts.data_replicas_required;
 	op->watermark		= BCH_WATERMARK_normal;
diff --git a/libbcachefs/io_types.h b/libbcachefs/io_types.h
index 0fbdfbf9..737f16d7 100644
--- a/libbcachefs/io_types.h
+++ b/libbcachefs/io_types.h
@@ -115,8 +115,8 @@ struct bch_write_op {
 	u16			flags;
 	s16			error; /* dio write path expects it to hold -ERESTARTSYS... */
 
+	unsigned		compression_opt:8;
 	unsigned		csum_type:4;
-	unsigned		compression_type:4;
 	unsigned		nr_replicas:4;
 	unsigned		nr_replicas_required:4;
 	unsigned		watermark:3;
diff --git a/libbcachefs/opts.c b/libbcachefs/opts.c
index 0c0c83fa..9dcc61ee 100644
--- a/libbcachefs/opts.c
+++ b/libbcachefs/opts.c
@@ -5,6 +5,7 @@
 #include "bcachefs.h"
 #include "compress.h"
 #include "disk_groups.h"
+#include "error.h"
 #include "opts.h"
 #include "super-io.h"
 #include "util.h"
@@ -16,6 +17,11 @@ const char * const bch2_error_actions[] = {
 	NULL
 };
 
+const char * const bch2_fsck_fix_opts[] = {
+	BCH_FIX_ERRORS_OPTS()
+	NULL
+};
+
 const char * const bch2_version_upgrade_opts[] = {
 	BCH_VERSION_UPGRADE_OPTS()
 	NULL
@@ -89,6 +95,37 @@ const char * const bch2_fs_usage_types[] = {
 
 #undef x
 
+int bch2_opt_fix_errors_parse(struct bch_fs *c, const char *val, u64 *res,
+			      struct printbuf *err)
+{
+	if (!val) {
+		*res = FSCK_FIX_yes;
+	} else {
+		int ret = match_string(bch2_fsck_fix_opts, -1, val);
+
+		if (ret < 0 && err)
+			prt_str(err, "fix_errors: invalid selection");
+		if (ret < 0)
+			return ret;
+		*res = ret;
+	}
+
+	return 0;
+}
+
+void bch2_opt_fix_errors_to_text(struct printbuf *out,
+				 struct bch_fs *c,
+				 struct bch_sb *sb,
+				 u64 v)
+{
+	prt_str(out, bch2_fsck_fix_opts[v]);
+}
+
+static const struct bch_opt_fn bch2_opt_fix_errors = {
+	.parse = bch2_opt_fix_errors_parse,
+	.to_text = bch2_opt_fix_errors_to_text,
+};
+
 const char * const bch2_d_types[BCH_DT_MAX] = {
 	[DT_UNKNOWN]	= "unknown",
 	[DT_FIFO]	= "fifo",
@@ -167,11 +204,9 @@ const struct bch_option bch2_opt_table[] = {
 #define OPT_UINT(_min, _max)	.type = BCH_OPT_UINT,			\
 				.min = _min, .max = _max
 #define OPT_STR(_choices)	.type = BCH_OPT_STR,			\
-				.min = 0, .max = ARRAY_SIZE(_choices),\
+				.min = 0, .max = ARRAY_SIZE(_choices),	\
 				.choices = _choices
-#define OPT_FN(_fn)		.type = BCH_OPT_FN,			\
-				.parse = _fn##_parse,			\
-				.to_text = _fn##_to_text
+#define OPT_FN(_fn)		.type = BCH_OPT_FN, .fn	= _fn
 
 #define x(_name, _bits, _flags, _type, _sb_opt, _default, _hint, _help)	\
 	[Opt_##_name] = {						\
@@ -267,15 +302,26 @@ int bch2_opt_parse(struct bch_fs *c,
 
 	switch (opt->type) {
 	case BCH_OPT_BOOL:
-		ret = kstrtou64(val, 10, res);
+		if (val) {
+			ret = kstrtou64(val, 10, res);
+		} else {
+			ret = 0;
+			*res = 1;
+		}
+
 		if (ret < 0 || (*res != 0 && *res != 1)) {
 			if (err)
-				prt_printf(err, "%s: must be bool",
-					   opt->attr.name);
+				prt_printf(err, "%s: must be bool", opt->attr.name);
 			return ret;
 		}
 		break;
 	case BCH_OPT_UINT:
+		if (!val) {
+			prt_printf(err, "%s: required value",
+				   opt->attr.name);
+			return -EINVAL;
+		}
+
 		ret = opt->flags & OPT_HUMAN_READABLE
 			? bch2_strtou64_h(val, res)
 			: kstrtou64(val, 10, res);
@@ -287,6 +333,12 @@ int bch2_opt_parse(struct bch_fs *c,
 		}
 		break;
 	case BCH_OPT_STR:
+		if (!val) {
+			prt_printf(err, "%s: required value",
+				   opt->attr.name);
+			return -EINVAL;
+		}
+
 		ret = match_string(opt->choices, -1, val);
 		if (ret < 0) {
 			if (err)
@@ -298,10 +350,7 @@ int bch2_opt_parse(struct bch_fs *c,
 		*res = ret;
 		break;
 	case BCH_OPT_FN:
-		if (!c)
-			return 0;
-
-		ret = opt->parse(c, val, res);
+		ret = opt->fn.parse(c, val, res, err);
 		if (ret < 0) {
 			if (err)
 				prt_printf(err, "%s: parse error",
@@ -341,10 +390,10 @@ void bch2_opt_to_text(struct printbuf *out,
 		if (flags & OPT_SHOW_FULL_LIST)
 			prt_string_option(out, opt->choices, v);
 		else
-			prt_printf(out, "%s", opt->choices[v]);
+			prt_str(out, opt->choices[v]);
 		break;
 	case BCH_OPT_FN:
-		opt->to_text(out, c, sb, v);
+		opt->fn.to_text(out, c, sb, v);
 		break;
 	default:
 		BUG();
@@ -405,31 +454,19 @@ int bch2_parse_mount_opts(struct bch_fs *c, struct bch_opts *opts,
 		name	= strsep(&opt, "=");
 		val	= opt;
 
-		if (val) {
-			id = bch2_mount_opt_lookup(name);
-			if (id < 0)
-				goto bad_opt;
-
-			ret = bch2_opt_parse(c, &bch2_opt_table[id], val, &v, &err);
-			if (ret < 0)
-				goto bad_val;
-		} else {
-			id = bch2_mount_opt_lookup(name);
-			v = 1;
-
-			if (id < 0 &&
-			    !strncmp("no", name, 2)) {
-				id = bch2_mount_opt_lookup(name + 2);
-				v = 0;
-			}
+		id = bch2_mount_opt_lookup(name);
 
-			if (id < 0)
-				goto bad_opt;
-
-			if (bch2_opt_table[id].type != BCH_OPT_BOOL)
-				goto no_val;
+		/* Check for the form "noopt", negation of a boolean opt: */
+		if (id < 0 &&
+		    !val &&
+		    !strncmp("no", name, 2)) {
+			id = bch2_mount_opt_lookup(name + 2);
+			val = "0";
 		}
 
+		if (id < 0)
+			goto bad_opt;
+
 		if (!(bch2_opt_table[id].flags & OPT_MOUNT))
 			goto bad_opt;
 
@@ -442,6 +479,10 @@ int bch2_parse_mount_opts(struct bch_fs *c, struct bch_opts *opts,
 		    !IS_ENABLED(CONFIG_BCACHEFS_QUOTA))
 			goto bad_opt;
 
+		ret = bch2_opt_parse(c, &bch2_opt_table[id], val, &v, &err);
+		if (ret < 0)
+			goto bad_val;
+
 		bch2_opt_set_by_id(opts, id, v);
 	}
 
@@ -456,10 +497,6 @@ bad_val:
 	pr_err("Invalid mount option %s", err.buf);
 	ret = -1;
 	goto out;
-no_val:
-	pr_err("Mount option %s requires a value", name);
-	ret = -1;
-	goto out;
 out:
 	kfree(copied_opts_start);
 	printbuf_exit(&err);
diff --git a/libbcachefs/opts.h b/libbcachefs/opts.h
index e105a742..8a9db110 100644
--- a/libbcachefs/opts.h
+++ b/libbcachefs/opts.h
@@ -8,7 +8,10 @@
 #include <linux/sysfs.h>
 #include "bcachefs_format.h"
 
+struct bch_fs;
+
 extern const char * const bch2_error_actions[];
+extern const char * const bch2_fsck_fix_opts[];
 extern const char * const bch2_version_upgrade_opts[];
 extern const char * const bch2_sb_features[];
 extern const char * const bch2_sb_compat[];
@@ -67,6 +70,11 @@ enum opt_type {
 	BCH_OPT_FN,
 };
 
+struct bch_opt_fn {
+	int (*parse)(struct bch_fs *, const char *, u64 *, struct printbuf *);
+	void (*to_text)(struct printbuf *, struct bch_fs *, struct bch_sb *, u64);
+};
+
 /**
  * x(name, shortopt, type, in mem type, mode, sb_opt)
  *
@@ -98,6 +106,18 @@ enum opt_type {
 #define BCACHEFS_VERBOSE_DEFAULT	false
 #endif
 
+#define BCH_FIX_ERRORS_OPTS()		\
+	x(exit,	0)			\
+	x(yes,	1)			\
+	x(no,	2)			\
+	x(ask,	3)
+
+enum fsck_err_opts {
+#define x(t, n)	FSCK_FIX_##t,
+	BCH_FIX_ERRORS_OPTS()
+#undef x
+};
+
 #define BCH_OPTS()							\
 	x(block_size,			u16,				\
 	  OPT_FS|OPT_FORMAT|						\
@@ -154,12 +174,12 @@ enum opt_type {
 	  NULL,		NULL)						\
 	x(compression,			u8,				\
 	  OPT_FS|OPT_INODE|OPT_FORMAT|OPT_MOUNT|OPT_RUNTIME,		\
-	  OPT_STR(bch2_compression_opts),				\
+	  OPT_FN(bch2_opt_compression),					\
 	  BCH_SB_COMPRESSION_TYPE,	BCH_COMPRESSION_OPT_none,	\
 	  NULL,		NULL)						\
 	x(background_compression,	u8,				\
 	  OPT_FS|OPT_INODE|OPT_FORMAT|OPT_MOUNT|OPT_RUNTIME,		\
-	  OPT_STR(bch2_compression_opts),				\
+	  OPT_FN(bch2_opt_compression),					\
 	  BCH_SB_BACKGROUND_COMPRESSION_TYPE,BCH_COMPRESSION_OPT_none,	\
 	  NULL,		NULL)						\
 	x(str_hash,			u8,				\
@@ -318,8 +338,8 @@ enum opt_type {
 	  NULL,		"Run fsck on mount")				\
 	x(fix_errors,			u8,				\
 	  OPT_FS|OPT_MOUNT,						\
-	  OPT_BOOL(),							\
-	  BCH2_NO_SB_OPT,		false,				\
+	  OPT_FN(bch2_opt_fix_errors),					\
+	  BCH2_NO_SB_OPT,		FSCK_FIX_exit,			\
 	  NULL,		"Fix errors during fsck without asking")	\
 	x(ratelimit_errors,		u8,				\
 	  OPT_FS|OPT_MOUNT,						\
@@ -495,8 +515,8 @@ struct bch_option {
 	u64			min, max;
 
 	const char * const *choices;
-	int (*parse)(struct bch_fs *, const char *, u64 *);
-	void (*to_text)(struct printbuf *, struct bch_fs *, struct bch_sb *, u64);
+
+	struct bch_opt_fn	fn;
 
 	const char		*hint;
 	const char		*help;
diff --git a/libbcachefs/rebalance.c b/libbcachefs/rebalance.c
index 989f37a3..c3d57723 100644
--- a/libbcachefs/rebalance.c
+++ b/libbcachefs/rebalance.c
@@ -5,6 +5,7 @@
 #include "btree_iter.h"
 #include "buckets.h"
 #include "clock.h"
+#include "compress.h"
 #include "disk_groups.h"
 #include "errcode.h"
 #include "extents.h"
@@ -45,7 +46,7 @@ static bool rebalance_pred(struct bch_fs *c, void *arg,
 		bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 			if (!p.ptr.cached &&
 			    p.crc.compression_type !=
-			    bch2_compression_opt_to_type[io_opts->background_compression])
+			    bch2_compression_opt_to_type(io_opts->background_compression))
 				data_opts->rewrite_ptrs |= 1U << i;
 			i++;
 		}
diff --git a/libbcachefs/recovery.c b/libbcachefs/recovery.c
index b04e1565..63b385d8 100644
--- a/libbcachefs/recovery.c
+++ b/libbcachefs/recovery.c
@@ -1162,12 +1162,9 @@ static void check_version_upgrade(struct bch_fs *c)
 			prt_str(&buf, " incomplete\n");
 		}
 
-		prt_str(&buf, "Doing ");
-		if (BCH_VERSION_MAJOR(old_version) != BCH_VERSION_MAJOR(new_version))
-			prt_str(&buf, "incompatible");
-		else
-			prt_str(&buf, "compatible");
-		prt_str(&buf, "version upgrade from ");
+		prt_printf(&buf, "Doing %s version upgrade from ",
+			   BCH_VERSION_MAJOR(old_version) != BCH_VERSION_MAJOR(new_version)
+			   ? "incompatible" : "compatible");
 		bch2_version_to_text(&buf, old_version);
 		prt_str(&buf, " to ");
 		bch2_version_to_text(&buf, new_version);
@@ -1178,7 +1175,7 @@ static void check_version_upgrade(struct bch_fs *c)
 			prt_str(&buf, "fsck required");
 
 			c->recovery_passes_explicit |= recovery_passes;
-			c->opts.fix_errors = FSCK_OPT_YES;
+			c->opts.fix_errors = FSCK_FIX_yes;
 		}
 
 		bch_info(c, "%s", buf.buf);
diff --git a/libbcachefs/subvolume.c b/libbcachefs/subvolume.c
index f118e585..c15b4781 100644
--- a/libbcachefs/subvolume.c
+++ b/libbcachefs/subvolume.c
@@ -12,9 +12,9 @@
 
 static int bch2_subvolume_delete(struct btree_trans *, u32);
 
-static inline u32 get_ancestor_below(struct bch_fs *c, u32 id, u32 ancestor)
+static inline u32 get_ancestor_below(struct snapshot_table *t, u32 id, u32 ancestor)
 {
-	struct snapshot_t *s = snapshot_t(c, id);
+	const struct snapshot_t *s = __snapshot_t(t, id);
 
 	if (s->skip[2] <= ancestor)
 		return s->skip[2];
@@ -27,22 +27,83 @@ static inline u32 get_ancestor_below(struct bch_fs *c, u32 id, u32 ancestor)
 
 bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
 {
+	struct snapshot_table *t;
+
 	EBUG_ON(c->curr_recovery_pass <= BCH_RECOVERY_PASS_check_snapshots);
 
+	rcu_read_lock();
+	t = rcu_dereference(c->snapshots);
+
 	while (id && id < ancestor)
-		id = get_ancestor_below(c, id, ancestor);
+		id = get_ancestor_below(t, id, ancestor);
+	rcu_read_unlock();
 
 	return id == ancestor;
 }
 
 static bool bch2_snapshot_is_ancestor_early(struct bch_fs *c, u32 id, u32 ancestor)
 {
+	struct snapshot_table *t;
+
+	rcu_read_lock();
+	t = rcu_dereference(c->snapshots);
+
 	while (id && id < ancestor)
-		id = snapshot_t(c, id)->parent;
+		id = __snapshot_t(t, id)->parent;
+	rcu_read_unlock();
 
 	return id == ancestor;
 }
 
+static inline u32 bch2_snapshot_depth(struct bch_fs *c, u32 parent)
+{
+	u32 depth;
+
+	rcu_read_lock();
+	depth = parent ? snapshot_t(c, parent)->depth + 1 : 0;
+	rcu_read_unlock();
+
+	return depth;
+}
+
+static noinline struct snapshot_t *__snapshot_t_mut(struct bch_fs *c, u32 id)
+{
+	size_t idx = U32_MAX - id;
+	size_t new_size;
+	struct snapshot_table *new, *old;
+
+	new_size = max(16UL, roundup_pow_of_two(idx + 1));
+
+	new = kvzalloc(struct_size(new, s, new_size), GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	old = c->snapshots;
+	if (old)
+		memcpy(new->s,
+		       rcu_dereference_protected(c->snapshots, true)->s,
+		       sizeof(new->s[0]) * c->snapshot_table_size);
+
+	rcu_assign_pointer(c->snapshots, new);
+	c->snapshot_table_size = new_size;
+	if (old)
+		kvfree_rcu(old);
+
+	return &rcu_dereference_protected(c->snapshots, true)->s[idx];
+}
+
+static inline struct snapshot_t *snapshot_t_mut(struct bch_fs *c, u32 id)
+{
+	size_t idx = U32_MAX - id;
+
+	lockdep_assert_held(&c->snapshot_table_lock);
+
+	if (likely(idx < c->snapshot_table_size))
+		return &rcu_dereference_protected(c->snapshots, true)->s[idx];
+
+	return __snapshot_t_mut(c, id);
+}
+
 /* Snapshot tree: */
 
 void bch2_snapshot_tree_to_text(struct printbuf *out, struct bch_fs *c,
@@ -202,12 +263,15 @@ int bch2_mark_snapshot(struct btree_trans *trans,
 {
 	struct bch_fs *c = trans->c;
 	struct snapshot_t *t;
+	int ret = 0;
+
+	mutex_lock(&c->snapshot_table_lock);
 
-	t = genradix_ptr_alloc(&c->snapshots,
-			       U32_MAX - new.k->p.offset,
-			       GFP_KERNEL);
-	if (!t)
-		return -BCH_ERR_ENOMEM_mark_snapshot;
+	t = snapshot_t_mut(c, new.k->p.offset);
+	if (!t) {
+		ret = -BCH_ERR_ENOMEM_mark_snapshot;
+		goto err;
+	}
 
 	if (new.k->type == KEY_TYPE_snapshot) {
 		struct bkey_s_c_snapshot s = bkey_s_c_to_snapshot(new);
@@ -231,8 +295,9 @@ int bch2_mark_snapshot(struct btree_trans *trans,
 		t->subvol	= 0;
 		t->tree		= 0;
 	}
-
-	return 0;
+err:
+	mutex_unlock(&c->snapshot_table_lock);
+	return ret;
 }
 
 static int snapshot_lookup(struct btree_trans *trans, u32 id,
@@ -285,9 +350,14 @@ static int bch2_snapshot_set_equiv(struct btree_trans *trans, struct bkey_s_c k)
 		nr_live += ret;
 	}
 
-	snapshot_t(c, id)->equiv = nr_live == 1
-		? snapshot_t(c, child[live_idx])->equiv
+	mutex_lock(&c->snapshot_table_lock);
+
+	snapshot_t_mut(c, id)->equiv = nr_live == 1
+		? snapshot_t_mut(c, child[live_idx])->equiv
 		: id;
+
+	mutex_unlock(&c->snapshot_table_lock);
+
 	return 0;
 }
 
@@ -505,16 +575,18 @@ static int snapshot_tree_ptr_good(struct btree_trans *trans,
 
 static u32 snapshot_rand_ancestor_get(struct bch_fs *c, u32 id)
 {
-	struct snapshot_t *s;
+	const struct snapshot_t *s;
 
 	if (!id)
 		return 0;
 
+	rcu_read_lock();
 	s = snapshot_t(c, id);
-	if (!s->parent)
-		return id;
+	if (s->parent)
+		id = bch2_snapshot_nth_parent(c, id, get_random_u32_below(s->depth));
+	rcu_read_unlock();
 
-	return bch2_snapshot_nth_parent(c, id, get_random_u32_below(s->depth));
+	return id;
 }
 
 static int snapshot_rand_ancestor_good(struct btree_trans *trans,
@@ -613,9 +685,7 @@ static int check_snapshot(struct btree_trans *trans,
 	struct bch_snapshot v;
 	struct bkey_i_snapshot *u;
 	u32 parent_id = bch2_snapshot_parent_early(c, k.k->p.offset);
-	struct snapshot_t *parent = parent_id
-		? snapshot_t(c, parent_id)
-		: NULL;
+	u32 real_depth;
 	struct printbuf buf = PRINTBUF;
 	bool should_have_subvol;
 	u32 i, id;
@@ -706,16 +776,18 @@ static int check_snapshot(struct btree_trans *trans,
 	}
 	ret = 0;
 
-	if (fsck_err_on(le32_to_cpu(s.depth) != (parent ? parent->depth + 1 : 0), c,
+	real_depth = bch2_snapshot_depth(c, parent_id);
+
+	if (fsck_err_on(le32_to_cpu(s.depth) != real_depth, c,
 			"snapshot with incorrect depth fields, should be %u:\n  %s",
-			parent->depth + 1,
+			real_depth,
 			(bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
 		u = bch2_bkey_make_mut_typed(trans, iter, &k, 0, snapshot);
 		ret = PTR_ERR_OR_ZERO(u);
 		if (ret)
 			goto err;
 
-		u->v.depth = cpu_to_le32(parent ? parent->depth + 1 : 0);
+		u->v.depth = cpu_to_le32(real_depth);
 		s = u->v;
 	}
 
@@ -799,9 +871,13 @@ static int check_subvol(struct btree_trans *trans,
 
 	if (!BCH_SUBVOLUME_SNAP(subvol.v)) {
 		u32 snapshot_root = bch2_snapshot_root(c, le32_to_cpu(subvol.v->snapshot));
-		u32 snapshot_tree = snapshot_t(c, snapshot_root)->tree;
+		u32 snapshot_tree;
 		struct bch_snapshot_tree st;
 
+		rcu_read_lock();
+		snapshot_tree = snapshot_t(c, snapshot_root)->tree;
+		rcu_read_unlock();
+
 		ret = bch2_snapshot_tree_lookup(trans, snapshot_tree, &st);
 
 		bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
@@ -845,7 +921,7 @@ int bch2_check_subvols(struct bch_fs *c)
 
 void bch2_fs_snapshots_exit(struct bch_fs *c)
 {
-	genradix_free(&c->snapshots);
+	kfree(c->snapshots);
 }
 
 int bch2_snapshots_read(struct bch_fs *c)
@@ -987,7 +1063,7 @@ static int create_snapids(struct btree_trans *trans, u32 parent, u32 tree,
 	struct bkey_i_snapshot *n;
 	struct bkey_s_c k;
 	unsigned i, j;
-	u32 depth = parent ? snapshot_t(c, parent)->depth + 1 : 0;
+	u32 depth = bch2_snapshot_depth(c, parent);
 	int ret;
 
 	bch2_trans_iter_init(trans, &iter, BTREE_ID_snapshots,
@@ -1126,7 +1202,7 @@ static int snapshot_delete_key(struct btree_trans *trans,
 			       struct bpos *last_pos)
 {
 	struct bch_fs *c = trans->c;
-	u32 equiv = snapshot_t(c, k.k->p.snapshot)->equiv;
+	u32 equiv = bch2_snapshot_equiv(c, k.k->p.snapshot);
 
 	if (!bkey_eq(k.k->p, *last_pos))
 		equiv_seen->nr = 0;
diff --git a/libbcachefs/subvolume.h b/libbcachefs/subvolume.h
index ab0b4a6d..6d134dab 100644
--- a/libbcachefs/subvolume.h
+++ b/libbcachefs/subvolume.h
@@ -32,17 +32,31 @@ int bch2_mark_snapshot(struct btree_trans *, enum btree_id, unsigned,
 	.min_val_size	= 24,					\
 })
 
-static inline struct snapshot_t *snapshot_t(struct bch_fs *c, u32 id)
+static inline struct snapshot_t *__snapshot_t(struct snapshot_table *t, u32 id)
 {
-	return genradix_ptr(&c->snapshots, U32_MAX - id);
+	return &t->s[U32_MAX - id];
 }
 
-static inline u32 bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
+static inline const struct snapshot_t *snapshot_t(struct bch_fs *c, u32 id)
+{
+	return __snapshot_t(rcu_dereference(c->snapshots), id);
+}
+
+static inline u32 __bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
 {
 	return snapshot_t(c, id)->parent;
 }
 
-static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
+static inline u32 bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	id = __bch2_snapshot_parent_early(c, id);
+	rcu_read_unlock();
+
+	return id;
+}
+
+static inline u32 __bch2_snapshot_parent(struct bch_fs *c, u32 id)
 {
 #ifdef CONFIG_BCACHEFS_DEBUG
 	u32 parent = snapshot_t(c, id)->parent;
@@ -59,10 +73,21 @@ static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
 #endif
 }
 
+static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	id = __bch2_snapshot_parent(c, id);
+	rcu_read_unlock();
+
+	return id;
+}
+
 static inline u32 bch2_snapshot_nth_parent(struct bch_fs *c, u32 id, u32 n)
 {
+	rcu_read_lock();
 	while (n--)
-		id = bch2_snapshot_parent(c, id);
+		id = __bch2_snapshot_parent(c, id);
+	rcu_read_unlock();
 
 	return id;
 }
@@ -71,37 +96,60 @@ static inline u32 bch2_snapshot_root(struct bch_fs *c, u32 id)
 {
 	u32 parent;
 
-	while ((parent = bch2_snapshot_parent(c, id)))
+	rcu_read_lock();
+	while ((parent = __bch2_snapshot_parent(c, id)))
 		id = parent;
+	rcu_read_unlock();
+
 	return id;
 }
 
-static inline u32 bch2_snapshot_equiv(struct bch_fs *c, u32 id)
+static inline u32 __bch2_snapshot_equiv(struct bch_fs *c, u32 id)
 {
 	return snapshot_t(c, id)->equiv;
 }
 
+static inline u32 bch2_snapshot_equiv(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	id = __bch2_snapshot_equiv(c, id);
+	rcu_read_unlock();
+
+	return id;
+}
+
 static inline bool bch2_snapshot_is_equiv(struct bch_fs *c, u32 id)
 {
-	return id == snapshot_t(c, id)->equiv;
+	return id == bch2_snapshot_equiv(c, id);
 }
 
-static inline u32 bch2_snapshot_internal_node(struct bch_fs *c, u32 id)
+static inline bool bch2_snapshot_is_internal_node(struct bch_fs *c, u32 id)
 {
-	struct snapshot_t *s = snapshot_t(c, id);
+	const struct snapshot_t *s;
+	bool ret;
+
+	rcu_read_lock();
+	s = snapshot_t(c, id);
+	ret = s->children[0];
+	rcu_read_unlock();
+
+	return ret;
+}
 
-	return s->children[0] || s->children[1];
+static inline u32 bch2_snapshot_is_leaf(struct bch_fs *c, u32 id)
+{
+	return !bch2_snapshot_is_internal_node(c, id);
 }
 
 static inline u32 bch2_snapshot_sibling(struct bch_fs *c, u32 id)
 {
-	struct snapshot_t *s;
-	u32 parent = bch2_snapshot_parent(c, id);
+	const struct snapshot_t *s;
+	u32 parent = __bch2_snapshot_parent(c, id);
 
 	if (!parent)
 		return 0;
 
-	s = snapshot_t(c, bch2_snapshot_parent(c, id));
+	s = snapshot_t(c, __bch2_snapshot_parent(c, id));
 	if (id == s->children[0])
 		return s->children[1];
 	if (id == s->children[1])
@@ -113,9 +161,15 @@ bool bch2_snapshot_is_ancestor(struct bch_fs *, u32, u32);
 
 static inline bool bch2_snapshot_has_children(struct bch_fs *c, u32 id)
 {
-	struct snapshot_t *t = snapshot_t(c, id);
+	const struct snapshot_t *t;
+	bool ret;
 
-	return (t->children[0]|t->children[1]) != 0;
+	rcu_read_lock();
+	t = snapshot_t(c, id);
+	ret = (t->children[0]|t->children[1]) != 0;
+	rcu_read_unlock();
+
+	return ret;
 }
 
 static inline bool snapshot_list_has_id(snapshot_id_list *s, u32 id)
diff --git a/libbcachefs/subvolume_types.h b/libbcachefs/subvolume_types.h
index 750d975a..c596e427 100644
--- a/libbcachefs/subvolume_types.h
+++ b/libbcachefs/subvolume_types.h
@@ -16,6 +16,10 @@ struct snapshot_t {
 	u32			equiv;
 };
 
+struct snapshot_table {
+	struct snapshot_t	s[0];
+};
+
 typedef struct {
 	u32		subvol;
 	u64		inum;
diff --git a/libbcachefs/super-io.c b/libbcachefs/super-io.c
index 35325381..e9ce3f33 100644
--- a/libbcachefs/super-io.c
+++ b/libbcachefs/super-io.c
@@ -658,11 +658,18 @@ int bch2_read_super(const char *path, struct bch_opts *opts,
 	struct printbuf err = PRINTBUF;
 	__le64 *i;
 	int ret;
-
+#ifndef __KERNEL__
+retry:
+#endif
 	memset(sb, 0, sizeof(*sb));
 	sb->mode	= FMODE_READ;
 	sb->have_bio	= true;
 
+#ifndef __KERNEL__
+	if (opt_get(*opts, direct_io) == false)
+		sb->mode |= FMODE_BUFFERED;
+#endif
+
 	if (!opt_get(*opts, noexcl))
 		sb->mode |= FMODE_EXCL;
 
@@ -747,7 +754,13 @@ int bch2_read_super(const char *path, struct bch_opts *opts,
 
 got_super:
 	if (le16_to_cpu(sb->sb->block_size) << 9 <
-	    bdev_logical_block_size(sb->bdev)) {
+	    bdev_logical_block_size(sb->bdev) &&
+	    opt_get(*opts, direct_io)) {
+#ifndef __KERNEL__
+		opt_set(*opts, direct_io, false);
+		bch2_free_super(sb);
+		goto retry;
+#endif
 		prt_printf(&err, "block size (%u) smaller than device block size (%u)",
 		       le16_to_cpu(sb->sb->block_size) << 9,
 		       bdev_logical_block_size(sb->bdev));
diff --git a/libbcachefs/super.c b/libbcachefs/super.c
index 426d2acf..9f1047a7 100644
--- a/libbcachefs/super.c
+++ b/libbcachefs/super.c
@@ -344,6 +344,19 @@ static int bch2_fs_read_write_late(struct bch_fs *c)
 {
 	int ret;
 
+	/*
+	 * Data move operations can't run until after check_snapshots has
+	 * completed, and bch2_snapshot_is_ancestor() is available.
+	 *
+	 * Ideally we'd start copygc/rebalance earlier instead of waiting for
+	 * all of recovery/fsck to complete:
+	 */
+	ret = bch2_copygc_start(c);
+	if (ret) {
+		bch_err(c, "error starting copygc thread");
+		return ret;
+	}
+
 	ret = bch2_rebalance_start(c);
 	if (ret) {
 		bch_err(c, "error starting rebalance thread");
@@ -403,12 +416,6 @@ static int __bch2_fs_read_write(struct bch_fs *c, bool early)
 		return ret;
 	}
 
-	ret = bch2_copygc_start(c);
-	if (ret) {
-		bch_err(c, "error starting copygc thread");
-		return ret;
-	}
-
 	if (!early) {
 		ret = bch2_fs_read_write_late(c);
 		if (ret)
diff --git a/libbcachefs/util.h b/libbcachefs/util.h
index ca1b799e..5fa29dab 100644
--- a/libbcachefs/util.h
+++ b/libbcachefs/util.h
@@ -64,7 +64,7 @@ static inline void *vpmalloc_noprof(size_t size, gfp_t gfp_mask)
 {
 	return (void *) get_free_pages_noprof(gfp_mask|__GFP_NOWARN,
 					      get_order(size)) ?:
-		__vmalloc(size, gfp_mask);
+		__vmalloc_noprof(size, gfp_mask);
 }
 #define vpmalloc(_size, _gfp)	alloc_hooks(vpmalloc_noprof(_size, _gfp))
 
diff --git a/linux/blkdev.c b/linux/blkdev.c
index 45b03fba..ea901a46 100644
--- a/linux/blkdev.c
+++ b/linux/blkdev.c
@@ -183,16 +183,19 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 	else if (mode & FMODE_WRITE)
 		flags = O_WRONLY;
 
+	if (!(mode & FMODE_BUFFERED))
+		flags |= O_DIRECT;
+
 #if 0
 	/* using O_EXCL doesn't work with opening twice for an O_SYNC fd: */
 	if (mode & FMODE_EXCL)
 		flags |= O_EXCL;
 #endif
-	buffered_fd = open(path, flags);
+	buffered_fd = open(path, flags & ~O_DIRECT);
 	if (buffered_fd < 0)
 		return ERR_PTR(-errno);
 
-	fd = open(path, flags|O_DIRECT);
+	fd = open(path, flags);
 	if (fd < 0)
 		fd = dup(buffered_fd);
 	if (fd < 0) {
@@ -200,9 +203,9 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 		return ERR_PTR(-errno);
 	}
 
-	sync_fd	= open(path, flags|O_DIRECT|O_SYNC);
+	sync_fd	= open(path, flags|O_SYNC);
 	if (sync_fd < 0)
-		sync_fd	= open(path, flags|O_SYNC);
+		sync_fd	= open(path, (flags & ~O_DIRECT)|O_SYNC);
 	if (sync_fd < 0) {
 		close(fd);
 		close(buffered_fd);
diff --git a/rust-src/src/cmd_list.rs b/rust-src/src/cmd_list.rs
index 2dc8d719..3f86b8cd 100644
--- a/rust-src/src/cmd_list.rs
+++ b/rust-src/src/cmd_list.rs
@@ -138,7 +138,7 @@ fn cmd_list_inner(opt: Cli) -> anyhow::Result<()> {
     opt_set!(fs_opts, errors,           bcachefs::bch_error_actions::BCH_ON_ERROR_continue as u8);
 
     if opt.fsck {
-        opt_set!(fs_opts, fix_errors,   bcachefs::fsck_err_opts::FSCK_OPT_YES as u8);
+        opt_set!(fs_opts, fix_errors,   bcachefs::fsck_err_opts::FSCK_FIX_yes as u8);
         opt_set!(fs_opts, norecovery,   0);
     }