X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=cmd_fusemount.c;h=216094f06ad33e3b34d8ed72e4c96d3b0e4a927e;hb=a0b523a67968f82ac6098913063ec6d74a274f19;hp=91c93607c46b99b858b7930e4ebbf4ddd64e25ba;hpb=415a3651fc8851056a0ab3946b90e123b113bac7;p=bcachefs-tools-debian

diff --git a/cmd_fusemount.c b/cmd_fusemount.c
index 91c9360..216094f 100644
--- a/cmd_fusemount.c
+++ b/cmd_fusemount.c
@@ -1,3 +1,5 @@
+#ifdef BCACHEFS_FUSE
+
 #include <errno.h>
 #include <float.h>
 #include <getopt.h>
@@ -44,7 +46,7 @@ static struct stat inode_to_stat(struct bch_fs *c,
 				 struct bch_inode_unpacked *bi)
 {
 	return (struct stat) {
-		.st_ino		= bi->bi_inum,
+		.st_ino		= unmap_root_ino(bi->bi_inum),
 		.st_size	= bi->bi_size,
 		.st_mode	= bi->bi_mode,
 		.st_uid		= bi->bi_uid,
@@ -63,7 +65,7 @@ static struct fuse_entry_param inode_to_entry(struct bch_fs *c,
 					      struct bch_inode_unpacked *bi)
 {
 	return (struct fuse_entry_param) {
-		.ino		= bi->bi_inum,
+		.ino		= unmap_root_ino(bi->bi_inum),
 		.generation	= bi->bi_generation,
 		.attr		= inode_to_stat(c, bi),
 		.attr_timeout	= DBL_MAX,
@@ -73,7 +75,11 @@ static struct fuse_entry_param inode_to_entry(struct bch_fs *c,
 
 static void bcachefs_fuse_init(void *arg, struct fuse_conn_info *conn)
 {
-	conn->want |= FUSE_CAP_WRITEBACK_CACHE;
+	if (conn->capable & FUSE_CAP_WRITEBACK_CACHE) {
+		fuse_log(FUSE_LOG_DEBUG, "fuse_init: activating writeback\n");
+		conn->want |= FUSE_CAP_WRITEBACK_CACHE;
+	} else
+		fuse_log(FUSE_LOG_DEBUG, "fuse_init: writeback not capable\n");
 
 	//conn->want |= FUSE_CAP_POSIX_ACL;
 }
@@ -94,6 +100,9 @@ static void bcachefs_fuse_lookup(fuse_req_t req, fuse_ino_t dir,
 	u64 inum;
 	int ret;
 
+	fuse_log(FUSE_LOG_DEBUG, "fuse_lookup(dir=%llu name=%s)\n",
+		 dir, name);
+
 	dir = map_root_ino(dir);
 
 	ret = bch2_inode_find_by_inum(c, dir, &bi);
@@ -106,20 +115,26 @@ static void bcachefs_fuse_lookup(fuse_req_t req, fuse_ino_t dir,
 
 	inum = bch2_dirent_lookup(c, dir, &hash_info, &qstr);
 	if (!inum) {
-		ret = -ENOENT;
-		goto err;
+		struct fuse_entry_param e = {
+			.attr_timeout	= DBL_MAX,
+			.entry_timeout	= DBL_MAX,
+		};
+		fuse_reply_entry(req, &e);
+		return;
 	}
 
 	ret = bch2_inode_find_by_inum(c, inum, &bi);
 	if (ret)
 		goto err;
 
-	bi.bi_inum = unmap_root_ino(bi.bi_inum);
+	fuse_log(FUSE_LOG_DEBUG, "fuse_lookup ret(inum=%llu)\n",
+		 bi.bi_inum);
 
 	struct fuse_entry_param e = inode_to_entry(c, &bi);
 	fuse_reply_entry(req, &e);
 	return;
 err:
+	fuse_log(FUSE_LOG_DEBUG, "fuse_lookup error %i\n", ret);
 	fuse_reply_err(req, -ret);
 }
 
@@ -131,15 +146,19 @@ static void bcachefs_fuse_getattr(fuse_req_t req, fuse_ino_t inum,
 	struct stat attr;
 	int ret;
 
+	fuse_log(FUSE_LOG_DEBUG, "fuse_getattr(inum=%llu)\n",
+		 inum);
+
 	inum = map_root_ino(inum);
 
 	ret = bch2_inode_find_by_inum(c, inum, &bi);
 	if (ret) {
+		fuse_log(FUSE_LOG_DEBUG, "fuse_getattr error %i\n", ret);
 		fuse_reply_err(req, -ret);
 		return;
 	}
 
-	bi.bi_inum = unmap_root_ino(bi.bi_inum);
+	fuse_log(FUSE_LOG_DEBUG, "fuse_getattr success\n");
 
 	attr = inode_to_stat(c, &bi);
 	fuse_reply_attr(req, &attr, DBL_MAX);
@@ -152,10 +171,13 @@ static void bcachefs_fuse_setattr(fuse_req_t req, fuse_ino_t inum,
 	struct bch_fs *c = fuse_req_userdata(req);
 	struct bch_inode_unpacked inode_u;
 	struct btree_trans trans;
-	struct btree_iter *iter;
+	struct btree_iter iter;
 	u64 now;
 	int ret;
 
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_setattr(%llu, %x)\n",
+		 inum, to_set);
+
 	inum = map_root_ino(inum);
 
 	bch2_trans_init(&trans, c, 0, 0);
@@ -163,8 +185,7 @@ retry:
 	bch2_trans_begin(&trans);
 	now = bch2_current_time(c);
 
-	iter = bch2_inode_peek(&trans, &inode_u, inum, BTREE_ITER_INTENT);
-	ret = PTR_ERR_OR_ZERO(iter);
+	ret = bch2_inode_peek(&trans, &iter, &inode_u, inum, BTREE_ITER_INTENT);
 	if (ret)
 		goto err;
 
@@ -184,12 +205,13 @@ retry:
 		inode_u.bi_atime = now;
 	if (to_set & FUSE_SET_ATTR_MTIME_NOW)
 		inode_u.bi_mtime = now;
+	/* TODO: CTIME? */
 
-	ret   = bch2_inode_write(&trans, iter, &inode_u) ?:
+	ret   = bch2_inode_write(&trans, &iter, &inode_u) ?:
 		bch2_trans_commit(&trans, NULL, NULL,
-				  BTREE_INSERT_ATOMIC|
 				  BTREE_INSERT_NOFAIL);
 err:
+        bch2_trans_iter_exit(&trans, &iter);
 	if (ret == -EINTR)
 		goto retry;
 
@@ -203,15 +225,6 @@ err:
 	}
 }
 
-static void bcachefs_fuse_readlink(fuse_req_t req, fuse_ino_t inum)
-{
-	//struct bch_fs *c = fuse_req_userdata(req);
-
-	//char *link = malloc();
-
-	//fuse_reply_readlink(req, link);
-}
-
 static int do_create(struct bch_fs *c, u64 dir,
 		     const char *name, mode_t mode, dev_t rdev,
 		     struct bch_inode_unpacked *new_inode)
@@ -223,7 +236,7 @@ static int do_create(struct bch_fs *c, u64 dir,
 
 	bch2_inode_init_early(c, new_inode);
 
-	return bch2_trans_do(c, NULL, BTREE_INSERT_ATOMIC,
+	return bch2_trans_do(c, NULL, NULL, 0,
 			bch2_create_trans(&trans,
 				dir, &dir_u,
 				new_inode, &qstr,
@@ -238,6 +251,8 @@ static void bcachefs_fuse_mknod(fuse_req_t req, fuse_ino_t dir,
 	struct bch_inode_unpacked new_inode;
 	int ret;
 
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_mknod(%llu, %s, %x, %x)\n",
+		 dir, name, mode, rdev);
 	ret = do_create(c, dir, name, mode, rdev, &new_inode);
 	if (ret)
 		goto err;
@@ -252,6 +267,12 @@ err:
 static void bcachefs_fuse_mkdir(fuse_req_t req, fuse_ino_t dir,
 				const char *name, mode_t mode)
 {
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_mkdir(%llu, %s, %x)\n",
+		 dir, name, mode);
+
+	BUG_ON(mode & S_IFMT);
+
+	mode |= S_IFDIR;
 	bcachefs_fuse_mknod(req, dir, name, mode, 0);
 }
 
@@ -263,9 +284,11 @@ static void bcachefs_fuse_unlink(fuse_req_t req, fuse_ino_t dir,
 	struct qstr qstr = QSTR(name);
 	int ret;
 
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_unlink(%llu, %s)\n", dir, name);
+
 	dir = map_root_ino(dir);
 
-	ret = bch2_trans_do(c, NULL, BTREE_INSERT_ATOMIC|BTREE_INSERT_NOFAIL,
+	ret = bch2_trans_do(c, NULL, NULL, BTREE_INSERT_NOFAIL,
 			    bch2_unlink_trans(&trans, dir, &dir_u,
 					      &inode_u, &qstr));
 
@@ -275,19 +298,13 @@ static void bcachefs_fuse_unlink(fuse_req_t req, fuse_ino_t dir,
 static void bcachefs_fuse_rmdir(fuse_req_t req, fuse_ino_t dir,
 				const char *name)
 {
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_rmdir(%llu, %s)\n", dir, name);
+
 	dir = map_root_ino(dir);
 
 	bcachefs_fuse_unlink(req, dir, name);
 }
 
-#if 0
-static void bcachefs_fuse_symlink(fuse_req_t req, const char *link,
-				  fuse_ino_t parent, const char *name)
-{
-	struct bch_fs *c = fuse_req_userdata(req);
-}
-#endif
-
 static void bcachefs_fuse_rename(fuse_req_t req,
 				 fuse_ino_t src_dir, const char *srcname,
 				 fuse_ino_t dst_dir, const char *dstname,
@@ -300,11 +317,15 @@ static void bcachefs_fuse_rename(fuse_req_t req,
 	struct qstr src_name = QSTR(dstname);
 	int ret;
 
+	fuse_log(FUSE_LOG_DEBUG,
+		 "bcachefs_fuse_rename(%llu, %s, %llu, %s, %x)\n",
+		 src_dir, srcname, dst_dir, dstname, flags);
+
 	src_dir = map_root_ino(src_dir);
 	dst_dir = map_root_ino(dst_dir);
 
 	/* XXX handle overwrites */
-	ret = bch2_trans_do(c, NULL, BTREE_INSERT_ATOMIC,
+	ret = bch2_trans_do(c, NULL, NULL, 0,
 		bch2_rename_trans(&trans,
 				  src_dir, &src_dir_u,
 				  dst_dir, &dst_dir_u,
@@ -319,13 +340,18 @@ static void bcachefs_fuse_link(fuse_req_t req, fuse_ino_t inum,
 			       fuse_ino_t newparent, const char *newname)
 {
 	struct bch_fs *c = fuse_req_userdata(req);
-	struct bch_inode_unpacked inode_u;
+	struct bch_inode_unpacked dir_u, inode_u;
 	struct qstr qstr = QSTR(newname);
 	int ret;
 
-	ret = bch2_trans_do(c, NULL, BTREE_INSERT_ATOMIC,
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_link(%llu, %llu, %s)\n",
+		 inum, newparent, newname);
+
+	newparent = map_root_ino(newparent);
+
+	ret = bch2_trans_do(c, NULL, NULL, 0,
 			    bch2_link_trans(&trans, newparent,
-					    inum, &inode_u, &qstr));
+					    inum, &dir_u, &inode_u, &qstr));
 
 	if (!ret) {
 		struct fuse_entry_param e = inode_to_entry(c, &inode_u);
@@ -372,51 +398,202 @@ static void bcachefs_fuse_read_endio(struct bio *bio)
 	closure_put(bio->bi_private);
 }
 
+struct fuse_align_io {
+	off_t		start;
+	size_t		pad_start;
+	off_t		end;
+	size_t		pad_end;
+	size_t		size;
+};
+
+/* Handle unaligned start and end */
+/* TODO: align to block_bytes, sector size, or page size? */
+static struct fuse_align_io align_io(const struct bch_fs *c, size_t size,
+				     off_t offset)
+{
+	struct fuse_align_io align;
+
+	BUG_ON(offset < 0);
+
+	align.start = round_down(offset, block_bytes(c));
+	align.pad_start = offset - align.start;
+
+	off_t end = offset + size;
+	align.end = round_up(end, block_bytes(c));
+	align.pad_end = align.end - end;
+
+	align.size = align.end - align.start;
+
+	return align;
+}
+
+/*
+ * Given an aligned number of bytes transferred, figure out how many unaligned
+ * bytes were transferred.
+ */
+static size_t align_fix_up_bytes(const struct fuse_align_io *align,
+				 size_t align_bytes)
+{
+	size_t bytes = 0;
+
+	if (align_bytes > align->pad_start) {
+		bytes = align_bytes - align->pad_start;
+		bytes = bytes > align->pad_end ? bytes - align->pad_end : 0;
+	}
+
+	return bytes;
+}
+
+/*
+ * Read aligned data.
+ */
+static int read_aligned(struct bch_fs *c, fuse_ino_t inum, size_t aligned_size,
+			off_t aligned_offset, void *buf)
+{
+	BUG_ON(aligned_size & (block_bytes(c) - 1));
+	BUG_ON(aligned_offset & (block_bytes(c) - 1));
+
+	struct bch_io_opts io_opts;
+	if (get_inode_io_opts(c, inum, &io_opts))
+		return -ENOENT;
+
+	struct bch_read_bio rbio;
+	struct bio_vec bv;
+	userbio_init(&rbio.bio, &bv, buf, aligned_size);
+	bio_set_op_attrs(&rbio.bio, REQ_OP_READ, REQ_SYNC);
+	rbio.bio.bi_iter.bi_sector	= aligned_offset >> 9;
+
+	struct closure cl;
+	closure_init_stack(&cl);
+
+	closure_get(&cl);
+	rbio.bio.bi_end_io		= bcachefs_fuse_read_endio;
+	rbio.bio.bi_private		= &cl;
+
+	bch2_read(c, rbio_init(&rbio.bio, io_opts), inum);
+
+	closure_sync(&cl);
+
+	return -blk_status_to_errno(rbio.bio.bi_status);
+}
+
 static void bcachefs_fuse_read(fuse_req_t req, fuse_ino_t inum,
 			       size_t size, off_t offset,
 			       struct fuse_file_info *fi)
 {
 	struct bch_fs *c = fuse_req_userdata(req);
 
-	if ((size|offset) & block_bytes(c)) {
-		fuse_reply_err(req, EINVAL);
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_read(%llu, %zd, %lld)\n",
+		 inum, size, offset);
+
+	/* Check inode size. */
+	struct bch_inode_unpacked bi;
+	int ret = bch2_inode_find_by_inum(c, inum, &bi);
+	if (ret) {
+		fuse_reply_err(req, -ret);
 		return;
 	}
 
-	struct bch_io_opts io_opts;
-	if (get_inode_io_opts(c, inum, &io_opts)) {
-		fuse_reply_err(req, ENOENT);
+	off_t end = min_t(u64, bi.bi_size, offset + size);
+	if (end <= offset) {
+		fuse_reply_buf(req, NULL, 0);
 		return;
 	}
+	size = end - offset;
 
-	void *buf = aligned_alloc(max(PAGE_SIZE, size), size);
+	struct fuse_align_io align = align_io(c, size, offset);
+
+	void *buf = aligned_alloc(PAGE_SIZE, align.size);
 	if (!buf) {
 		fuse_reply_err(req, ENOMEM);
 		return;
 	}
 
-	struct bch_read_bio	rbio;
+	ret = read_aligned(c, inum, align.size, align.start, buf);
+
+	if (likely(!ret))
+		fuse_reply_buf(req, buf + align.pad_start, size);
+	else
+		fuse_reply_err(req, -ret);
+
+	free(buf);
+}
+
+static int inode_update_times(struct bch_fs *c, fuse_ino_t inum)
+{
+	struct btree_trans trans;
+	struct btree_iter iter;
+	struct bch_inode_unpacked inode_u;
+	int ret = 0;
+	u64 now;
+
+	bch2_trans_init(&trans, c, 0, 0);
+retry:
+	bch2_trans_begin(&trans);
+	now = bch2_current_time(c);
+
+	ret = bch2_inode_peek(&trans, &iter, &inode_u, inum, BTREE_ITER_INTENT);
+	if (ret)
+		goto err;
+
+	inode_u.bi_mtime = now;
+	inode_u.bi_ctime = now;
+
+	ret = bch2_inode_write(&trans, &iter, &inode_u);
+	if (ret)
+		goto err;
+
+	ret = bch2_trans_commit(&trans, NULL, NULL,
+				BTREE_INSERT_NOFAIL);
+
+err:
+        bch2_trans_iter_exit(&trans, &iter);
+	if (ret == -EINTR)
+		goto retry;
+
+	bch2_trans_exit(&trans);
+	return ret;
+}
+
+static int write_aligned(struct bch_fs *c, fuse_ino_t inum,
+			 struct bch_io_opts io_opts, void *buf,
+			 size_t aligned_size, off_t aligned_offset,
+			 off_t new_i_size, size_t *written_out)
+{
+	struct bch_write_op	op = { 0 };
 	struct bio_vec		bv;
 	struct closure		cl;
 
+	BUG_ON(aligned_size & (block_bytes(c) - 1));
+	BUG_ON(aligned_offset & (block_bytes(c) - 1));
+
+	*written_out = 0;
+
 	closure_init_stack(&cl);
-	userbio_init(&rbio.bio, &bv, buf, size);
-	bio_set_op_attrs(&rbio.bio, REQ_OP_READ, REQ_SYNC);
-	rbio.bio.bi_iter.bi_sector	= offset >> 9;
-	rbio.bio.bi_end_io		= bcachefs_fuse_read_endio;
-	rbio.bio.bi_private		= &cl;
 
-	bch2_read(c, rbio_init(&rbio.bio, io_opts), inum);
+	bch2_write_op_init(&op, c, io_opts); /* XXX reads from op?! */
+	op.write_point	= writepoint_hashed(0);
+	op.nr_replicas	= io_opts.data_replicas;
+	op.target	= io_opts.foreground_target;
+	op.pos		= POS(inum, aligned_offset >> 9);
+	op.new_i_size	= new_i_size;
 
-	closure_sync(&cl);
+	userbio_init(&op.wbio.bio, &bv, buf, aligned_size);
+	bio_set_op_attrs(&op.wbio.bio, REQ_OP_WRITE, REQ_SYNC);
 
-	if (likely(!rbio.bio.bi_status)) {
-		fuse_reply_buf(req, buf, size);
-	} else {
-		fuse_reply_err(req, -blk_status_to_errno(rbio.bio.bi_status));
+	if (bch2_disk_reservation_get(c, &op.res, aligned_size >> 9,
+				      op.nr_replicas, 0)) {
+		/* XXX: use check_range_allocated like dio write path */
+		return -ENOSPC;
 	}
 
-	free(buf);
+	closure_call(&op.cl, bch2_write, NULL, &cl);
+	closure_sync(&cl);
+
+	if (!op.error)
+		*written_out = op.written << 9;
+
+	return op.error;
 }
 
 static void bcachefs_fuse_write(fuse_req_t req, fuse_ino_t inum,
@@ -426,50 +603,185 @@ static void bcachefs_fuse_write(fuse_req_t req, fuse_ino_t inum,
 {
 	struct bch_fs *c	= fuse_req_userdata(req);
 	struct bch_io_opts	io_opts;
-	struct bch_write_op	op;
-	struct bio_vec		bv;
-	struct closure		cl;
+	size_t			aligned_written;
+	int			ret = 0;
 
-	if ((size|offset) & block_bytes(c)) {
-		fuse_reply_err(req, EINVAL);
-		return;
-	}
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_write(%llu, %zd, %lld)\n",
+		 inum, size, offset);
 
-	closure_init_stack(&cl);
+	struct fuse_align_io align = align_io(c, size, offset);
+	void *aligned_buf = aligned_alloc(PAGE_SIZE, align.size);
+	BUG_ON(!aligned_buf);
 
 	if (get_inode_io_opts(c, inum, &io_opts)) {
-		fuse_reply_err(req, ENOENT);
-		return;
+		ret = -ENOENT;
+		goto err;
 	}
 
-	bch2_write_op_init(&op, c, io_opts);
-	op.write_point	= writepoint_hashed(0);
-	op.nr_replicas	= io_opts.data_replicas;
-	op.target	= io_opts.foreground_target;
-	op.pos		= POS(inum, offset >> 9);
+	/* Realign the data and read in start and end, if needed */
 
-	userbio_init(&op.wbio.bio, &bv, (void *) buf, size);
-	bio_set_op_attrs(&op.wbio.bio, REQ_OP_WRITE, REQ_SYNC);
+	/* Read partial start data. */
+	if (align.pad_start) {
+		memset(aligned_buf, 0, block_bytes(c));
 
-	if (bch2_disk_reservation_get(c, &op.res, size >> 9,
-				      op.nr_replicas, 0)) {
-		/* XXX: use check_range_allocated like dio write path */
-		fuse_reply_err(req, ENOSPC);
-		return;
+		ret = read_aligned(c, inum, block_bytes(c), align.start,
+				   aligned_buf);
+		if (ret)
+			goto err;
 	}
 
-	closure_call(&op.cl, bch2_write, NULL, &cl);
-	closure_sync(&cl);
+	/*
+	 * Read partial end data. If the whole write fits in one block, the
+	 * start data and the end data are the same so this isn't needed.
+	 */
+	if (align.pad_end &&
+	    !(align.pad_start && align.size == block_bytes(c))) {
+		off_t partial_end_start = align.end - block_bytes(c);
+		size_t buf_offset = align.size - block_bytes(c);
 
-	if (op.written) {
-		fuse_reply_write(req, (size_t) op.written << 9);
-	} else {
-		BUG_ON(!op.error);
-		fuse_reply_err(req, -op.error);
+		memset(aligned_buf + buf_offset, 0, block_bytes(c));
+
+		ret = read_aligned(c, inum, block_bytes(c), partial_end_start,
+				   aligned_buf + buf_offset);
+		if (ret)
+			goto err;
+	}
+
+	/* Overlay what we want to write. */
+	memcpy(aligned_buf + align.pad_start, buf, size);
+
+	/* Actually write. */
+	ret = write_aligned(c, inum, io_opts, aligned_buf,
+			    align.size, align.start,
+			    offset + size, &aligned_written);
+
+	/* Figure out how many unaligned bytes were written. */
+	size_t written = align_fix_up_bytes(&align, aligned_written);
+	BUG_ON(written > size);
+
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_write: wrote %zd bytes\n",
+		 written);
+
+	if (written > 0)
+		ret = 0;
+
+	/*
+	 * Update inode times.
+	 * TODO: Integrate with bch2_extent_update()
+	 */
+	if (!ret)
+		ret = inode_update_times(c, inum);
+
+	if (!ret) {
+		BUG_ON(written == 0);
+		fuse_reply_write(req, written);
+		free(aligned_buf);
+		return;
 	}
+
+err:
+	fuse_reply_err(req, -ret);
+	free(aligned_buf);
+}
+
+static void bcachefs_fuse_symlink(fuse_req_t req, const char *link,
+				  fuse_ino_t dir, const char *name)
+{
+	struct bch_fs *c = fuse_req_userdata(req);
+	struct bch_inode_unpacked new_inode;
+	size_t link_len = strlen(link);
+	int ret;
+
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_symlink(%s, %llu, %s)\n",
+		 link, dir, name);
+
+	dir = map_root_ino(dir);
+
+	ret = do_create(c, dir, name, S_IFLNK|S_IRWXUGO, 0, &new_inode);
+	if (ret)
+		goto err;
+
+	struct bch_io_opts io_opts;
+	ret = get_inode_io_opts(c, new_inode.bi_inum, &io_opts);
+	if (ret)
+		goto err;
+
+	struct fuse_align_io align = align_io(c, link_len + 1, 0);
+
+	void *aligned_buf = aligned_alloc(PAGE_SIZE, align.size);
+	BUG_ON(!aligned_buf);
+
+	memset(aligned_buf, 0, align.size);
+	memcpy(aligned_buf, link, link_len); /* already terminated */
+
+	size_t aligned_written;
+	ret = write_aligned(c, new_inode.bi_inum, io_opts, aligned_buf,
+			    align.size, align.start, link_len + 1,
+			    &aligned_written);
+	free(aligned_buf);
+
+	if (ret)
+		goto err;
+
+	size_t written = align_fix_up_bytes(&align, aligned_written);
+	BUG_ON(written != link_len + 1); // TODO: handle short
+
+	ret = inode_update_times(c, new_inode.bi_inum);
+	if (ret)
+		goto err;
+
+	new_inode.bi_size = written;
+
+	struct fuse_entry_param e = inode_to_entry(c, &new_inode);
+	fuse_reply_entry(req, &e);
+	return;
+
+err:
+	fuse_reply_err(req, -ret);
+}
+
+static void bcachefs_fuse_readlink(fuse_req_t req, fuse_ino_t inum)
+{
+	struct bch_fs *c = fuse_req_userdata(req);
+	char *buf = NULL;
+
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_readlink(%llu)\n", inum);
+
+	struct bch_inode_unpacked bi;
+	int ret = bch2_inode_find_by_inum(c, inum, &bi);
+	if (ret)
+		goto err;
+
+	struct fuse_align_io align = align_io(c, bi.bi_size, 0);
+
+	ret = -ENOMEM;
+	buf = aligned_alloc(PAGE_SIZE, align.size);
+	if (!buf)
+		goto err;
+
+	ret = read_aligned(c, inum, align.size, align.start, buf);
+	if (ret)
+		goto err;
+
+	BUG_ON(buf[align.size - 1] != 0);
+
+	fuse_reply_readlink(req, buf);
+
+err:
+	if (ret)
+		fuse_reply_err(req, -ret);
+
+	free(buf);
 }
 
 #if 0
+/*
+ * FUSE flush is essentially the close() call, however it is not guaranteed
+ * that one flush happens per open/create.
+ *
+ * It doesn't have to do anything, and is mostly relevant for NFS-style
+ * filesystems where close has some relationship to caching.
+ */
 static void bcachefs_fuse_flush(fuse_req_t req, fuse_ino_t inum,
 				struct fuse_file_info *fi)
 {
@@ -495,43 +807,44 @@ static void bcachefs_fuse_opendir(fuse_req_t req, fuse_ino_t inum,
 }
 #endif
 
-struct fuse_dir_entry {
-	u64		ino;
-	unsigned	type;
-	char		name[0];
-};
-
 struct fuse_dir_context {
 	struct dir_context	ctx;
 	fuse_req_t		req;
 	char			*buf;
 	size_t			bufsize;
-
-	struct fuse_dir_entry	*prev;
 };
 
-static int fuse_send_dir_entry(struct fuse_dir_context *ctx, loff_t pos)
-{
-	struct fuse_dir_entry *de = ctx->prev;
-	ctx->prev = NULL;
-
-	struct stat statbuf = {
-		.st_ino		= unmap_root_ino(de->ino),
-		.st_mode	= de->type << 12,
-	};
+struct fuse_dirent {
+	uint64_t	ino;
+	uint64_t	off;
+	uint32_t	namelen;
+	uint32_t	type;
+	char name[];
+};
 
-	size_t len = fuse_add_direntry(ctx->req, ctx->buf, ctx->bufsize,
-				       de->name, &statbuf, pos);
+#define FUSE_NAME_OFFSET offsetof(struct fuse_dirent, name)
+#define FUSE_DIRENT_ALIGN(x) \
+	(((x) + sizeof(uint64_t) - 1) & ~(sizeof(uint64_t) - 1))
 
-	free(de);
+static size_t fuse_add_direntry2(char *buf, size_t bufsize,
+				 const char *name, int namelen,
+				 const struct stat *stbuf, off_t off)
+{
+	size_t entlen		= FUSE_NAME_OFFSET + namelen;
+	size_t entlen_padded	= FUSE_DIRENT_ALIGN(entlen);
+	struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
 
-	if (len > ctx->bufsize)
-		return -EINVAL;
+	if ((buf == NULL) || (entlen_padded > bufsize))
+		return entlen_padded;
 
-	ctx->buf	+= len;
-	ctx->bufsize	-= len;
+	dirent->ino = stbuf->st_ino;
+	dirent->off = off;
+	dirent->namelen = namelen;
+	dirent->type = (stbuf->st_mode & S_IFMT) >> 12;
+	memcpy(dirent->name, name, namelen);
+	memset(dirent->name + namelen, 0, entlen_padded - entlen);
 
-	return 0;
+	return entlen_padded;
 }
 
 static int fuse_filldir(struct dir_context *_ctx,
@@ -541,47 +854,42 @@ static int fuse_filldir(struct dir_context *_ctx,
 	struct fuse_dir_context *ctx =
 		container_of(_ctx, struct fuse_dir_context, ctx);
 
-	fuse_log(FUSE_LOG_DEBUG, "fuse_filldir(ctx={.ctx={.pos=%llu}}, "
-		 "name=%s, namelen=%d, pos=%lld, dir=%llu, type=%u)\n",
-		 ctx->ctx.pos, name, namelen, pos, ino, type);
+	struct stat statbuf = {
+		.st_ino		= unmap_root_ino(ino),
+		.st_mode	= type << 12,
+	};
 
-	/*
-	 * We have to emit directory entries after reading the next entry,
-	 * because the previous entry contains a pointer to next.
-	 */
-	if (ctx->prev) {
-		int ret = fuse_send_dir_entry(ctx, pos);
-		if (ret)
-			return ret;
-	}
+	fuse_log(FUSE_LOG_DEBUG, "fuse_filldir(name=%s inum=%llu pos=%llu)\n",
+		 name, statbuf.st_ino, pos);
 
-	struct fuse_dir_entry *cur = malloc(sizeof *cur + namelen + 1);
-	cur->ino = ino;
-	cur->type = type;
-	memcpy(cur->name, name, namelen);
-	cur->name[namelen] = 0;
+	size_t len = fuse_add_direntry2(ctx->buf,
+					ctx->bufsize,
+					name,
+					namelen,
+					&statbuf,
+					pos + 1);
+
+	if (len > ctx->bufsize)
+		return -1;
 
-	ctx->prev = cur;
+	ctx->buf	+= len;
+	ctx->bufsize	-= len;
 
 	return 0;
 }
 
 static bool handle_dots(struct fuse_dir_context *ctx, fuse_ino_t dir)
 {
-	int ret = 0;
-
 	if (ctx->ctx.pos == 0) {
-		ret = fuse_filldir(&ctx->ctx, ".", 1, ctx->ctx.pos,
-				   unmap_root_ino(dir), DT_DIR);
-		if (ret < 0)
+		if (fuse_filldir(&ctx->ctx, ".", 1, ctx->ctx.pos,
+				 dir, DT_DIR) < 0)
 			return false;
 		ctx->ctx.pos = 1;
 	}
 
 	if (ctx->ctx.pos == 1) {
-		ret = fuse_filldir(&ctx->ctx, "..", 2, ctx->ctx.pos,
-				   /*TODO: parent*/ 1, DT_DIR);
-		if (ret < 0)
+		if (fuse_filldir(&ctx->ctx, "..", 2, ctx->ctx.pos,
+				 /*TODO: parent*/ 1, DT_DIR) < 0)
 			return false;
 		ctx->ctx.pos = 2;
 	}
@@ -623,20 +931,7 @@ static void bcachefs_fuse_readdir(fuse_req_t req, fuse_ino_t dir,
 		goto reply;
 
 	ret = bch2_readdir(c, dir, &ctx.ctx);
-
 reply:
-	/*
-	 * If we have something to send, the error above doesn't matter.
-	 *
-	 * Alternatively, if this send fails, but we previously sent something,
-	 * then this is a success.
-	 */
-	if (ctx.prev) {
-		ret = fuse_send_dir_entry(&ctx, ctx.ctx.pos);
-		if (ret && ctx.buf != buf)
-			ret = 0;
-	}
-
 	if (!ret) {
 		fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_readdir reply %zd\n",
 					ctx.buf - buf);
@@ -724,6 +1019,9 @@ static void bcachefs_fuse_create(fuse_req_t req, fuse_ino_t dir,
 	struct bch_inode_unpacked new_inode;
 	int ret;
 
+	fuse_log(FUSE_LOG_DEBUG, "bcachefs_fuse_create(%llu, %s, %x)\n",
+		 dir, name, mode);
+
 	ret = do_create(c, dir, name, mode, 0, &new_inode);
 	if (ret)
 		goto err;
@@ -763,7 +1061,7 @@ static const struct fuse_lowlevel_ops bcachefs_fuse_ops = {
 	.mkdir		= bcachefs_fuse_mkdir,
 	.unlink		= bcachefs_fuse_unlink,
 	.rmdir		= bcachefs_fuse_rmdir,
-	//.symlink	= bcachefs_fuse_symlink,
+	.symlink	= bcachefs_fuse_symlink,
 	.rename		= bcachefs_fuse_rename,
 	.link		= bcachefs_fuse_link,
 	.open		= bcachefs_fuse_open,
@@ -946,6 +1244,9 @@ int cmd_fusemount(int argc, char *argv[])
 	if (fuse_session_mount(se, fuse_opts.mountpoint))
 		die("fuse_mount err: %m");
 
+	/* This print statement is a trigger for tests. */
+	printf("Fuse mount initialized.\n");
+
 	fuse_daemonize(fuse_opts.foreground);
 
 	ret = fuse_session_loop(se);
@@ -962,3 +1263,5 @@ out:
 
 	return ret ? 1 : 0;
 }
+
+#endif /* BCACHEFS_FUSE */