panic: runtime error: invalid memory address or nil pointer dereference while trying to mount directory using FUSE

[angad-k]

Describe the bug
Seaweed is giving a runtime error whenever I'm trying to mount a folder using FUSE.

System Setup

• Started seaweed with weed server -filer=true. The related logs are as follows:

I0716 23:45:55  6308 master.go:151] current: 192.168.0.107:9333 peers:
I0716 23:45:55  6308 file_util.go:20] Folder /tmp Permission: -rwxrwxrwx
I0716 23:45:55  6308 master.go:151] current: 192.168.0.107:9333 peers:192.168.0.107:9333
I0716 23:45:55  6308 master_server.go:108] Volume Size Limit is 30000 MB
I0716 23:45:55  6308 file_util.go:20] Folder /tmp Permission: -rwxrwxrwx
I0716 23:45:55  6308 master_server.go:196] adminScripts:
I0716 23:45:55  6308 master.go:114] Start Seaweed Master 30GB 1.85 5a4f258 at 0.0.0.0:9333
I0716 23:45:55  6308 raft_server.go:47] Starting RaftServer with 192.168.0.107:9333
I0716 23:45:55  6308 raft_server.go:55] Peers Change: [] => [192.168.0.107:9333]
I0716 23:45:55  6308 disk_location.go:123] Store started on dir: /tmp with 0 volumes max 8
I0716 23:45:55  6308 disk_location.go:126] Store started on dir: /tmp with 0 ec shards
I0716 23:45:55  6308 volume_grpc_client_to_master.go:27] Volume server start with seed master nodes: [192.168.0.107:9333]
I0716 23:45:55  6308 volume.go:319] Start Seaweed volume server 30GB 1.85 5a4f258 at 0.0.0.0:8080
I0716 23:45:55  6308 volume_grpc_client_to_master.go:71] SendHeartbeat to 192.168.0.107:9333: rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 192.168.0.107:19333: connect: connection refused"
I0716 23:45:55  6308 volume_grpc_client_to_master.go:51] heartbeat error: rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 192.168.0.107:19333: connect: connection refused"
I0716 23:45:55  6308 raft_server.go:75] Initializing new cluster
I0716 23:45:55  6308 raft_server.go:88] current cluster leader: 192.168.0.107:9333
I0716 23:45:55  6308 master_server.go:151] [ 192.168.0.107:9333 ] I am the leader!
I0716 23:45:55  6308 master.go:138] Start Seaweed Master 30GB 1.85 5a4f258 grpc server at 0.0.0.0:19333
I0716 23:45:55  6308 master_grpc_server.go:253] + client master@192.168.0.107:56862
I0716 23:45:56  6308 master_grpc_server.go:253] + client filer@192.168.0.107:8888
I0716 23:45:56  6308 leveldb_store.go:41] filer store dir: .
I0716 23:45:56  6308 file_util.go:20] Folder . Permission: -rwxrwxr-x
I0716 23:45:56  6308 configuration.go:25] Configure filer for leveldb
I0716 23:45:56  6308 filer.go:144] Start Seaweed Filer 30GB 1.85 5a4f258 at 192.168.0.107:8888
I0716 23:45:56  6308 filer_grpc_server_sub_meta.go:130] + listener filer@192.168.0.107:45336
I0716 23:45:56  6308 filer_grpc_server_sub_meta.go:60]  filer@192.168.0.107:45336 local subscribe / from 2020-07-16 23:45:56.559028587 +0530 IST
I0716 23:46:00  6308 volume_grpc_client_to_master.go:74] Heartbeat to: 192.168.0.107:9333
I0716 23:46:00  6308 node.go:278] topo adds child DefaultDataCenter
I0716 23:46:00  6308 node.go:278] topo:DefaultDataCenter adds child DefaultRack
I0716 23:46:00  6308 node.go:278] topo:DefaultDataCenter:DefaultRack adds child 192.168.0.107:8080
I0716 23:46:00  6308 master_grpc_server.go:74] added volume server 192.168.0.107:8080

• Then tried to mount a directory with weed mount -filer=localhost:8888 -dir=~/seaweed/dir1 -filer.path=/ This gave the error :

This is SeaweedFS version 30GB 1.85 5a4f258 linux amd64
current uid=1000 gid=1000
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x177ba95]

goroutine 1 [running]:
github.com/chrislusf/seaweedfs/weed/command.RunMount(0x2ff4c40, 0x12, 0x0)
	/home/travis/gopath/src/github.com/chrislusf/seaweedfs/weed/command/mount_std.go:169 +0xa15
github.com/chrislusf/seaweedfs/weed/command.runMount(0x2fdd8a0, 0xc00003a0e0, 0x0, 0x0, 0x0)
	/home/travis/gopath/src/github.com/chrislusf/seaweedfs/weed/command/mount_std.go:41 +0xc3
main.main()
	/home/travis/gopath/src/github.com/chrislusf/seaweedfs/weed/weed.go:66 +0x2f9

• OS version

Distributor ID:	Ubuntu
Description:	Ubuntu 20.04 LTS
Release:	20.04
Codename:	focal

• output of weed version : version 30GB 1.85 5a4f258 linux amd64

• if using filer, show the content of filer.toml

[leveldb]
enabled = true
dir = "."	

Expected behavior
The directory should get mounted.

[chrislusf]

try to use an absolute path in -dir=~/seaweed/dir1

[chrislusf]

Added fixes to resolve the home directory tilde ~