mount: add -volumeName to name the disk explicitly (#11165)

* mount: let volumeName take an explicit override

volumeName only ever derived the disk's label from -filer.path, -dir,
or the filer address, so a name that happened to collide with
something else - e.g. a UNC share's own name - could not be changed
without moving what was mounted. Give it an override parameter that
wins over all three; nothing passes one yet.

* mount: add -volumeName to name the disk explicitly

Windows has no equivalent of the "weed fuse" -o passthrough that lets
a Linux or macOS mount override its derived volname, so a name picked
up from -dir - e.g. a UNC share's own name - could not be changed
short of moving what was mounted. -volumeName overrides it on every
platform.

* mount: document -volumeName

* mount: scope -volumeName's help text to macOS and Windows

Linux has no volume-label mount option for -volumeName to feed, so
the flag's own description says where it applies instead of leaving
that unstated.

* mount: forward -volumeName through the weed fuse option parser

weed fuse (the /etc/fstab helper) turns -o key=value into the same
MountOptions weed mount takes, but volumeName had no case, so it fell
through to being forwarded as a literal, unrecognized FUSE option
instead of ever reaching mountOptions.volumeName.

* mount: apply -volumeName to FsName on Linux and FreeBSD

FsName only ever took the filer address and -filer.path, so
-volumeName had nothing to override there and silently did nothing;
the skipAutofs case still forces "fuse", since that name is what
util-linux/mount requires to recognize the pseudo filesystem.

weed/command/mount_common_test.go

@@ -10,8 +10,24 @@ func Test_volumeName(t *testing.T) {
 		filer              string
 		filerMountRootPath string
 		dir                string
+		override           string
 		expected           string
 	}{
+		{
+			name:               "an override outranks the mounted path and the mount point",
+			filer:              "127.0.0.1:8888",
+			filerMountRootPath: "/buckets/videos",
+			dir:                `\\seaweedfs\Images`,
+			override:           "MyDisk",
+			expected:           "MyDisk",
+		},
+		{
+			name:               "an override still gets commas replaced",
+			filer:              "127.0.0.1:8888",
+			filerMountRootPath: "/",
+			override:           "My, Disk",
+			expected:           "My+ Disk",
+		},
 		{
 			name:               "a drive letter leaves only the filer to fall back on",
 			filer:              "127.0.0.1:8888",
@@ -80,8 +96,8 @@ func Test_volumeName(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := volumeName(tt.filer, tt.filerMountRootPath, tt.dir); got != tt.expected {
-				t.Errorf("volumeName(%q, %q, %q) = %q, want %q", tt.filer, tt.filerMountRootPath, tt.dir, got, tt.expected)
+			if got := volumeName(tt.filer, tt.filerMountRootPath, tt.dir, tt.override); got != tt.expected {
+				t.Errorf("volumeName(%q, %q, %q, %q) = %q, want %q", tt.filer, tt.filerMountRootPath, tt.dir, tt.override, got, tt.expected)
 			}
 		})
 	}