fstab: Refactor to be able to add ssd-specific options

src/modules/fstab/main.py

@@ -18,6 +18,7 @@
 #   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import re
 
 import libcalamares
 
@@ -30,6 +31,7 @@ HEADER = """# /etc/fstab: static file system information.
 #
 # <file system>                           <mount point>  <type>  <options>  <dump>  <pass>"""
 
+# Turn Parted filesystem names into fstab names
 FS_MAP = {
     "fat": "vfat",
     "linuxswap": "swap",
@@ -41,16 +43,78 @@ def mkdir_p(path):
         os.makedirs(path)
 
 
-def generate_fstab_line(partition):
+def is_ssd_disk(disk_name):
+    filename = os.path.join("/sys/block", disk_name, "queue/rotational")
+    if not os.path.exists(filename):
+        # Should not happen unless sysfs changes, but better safe than sorry
+        return False
+    with open(filename) as f:
+        return f.read() == "0\n"
+
+
+def disk_name_for_partition(partition):
+    name = os.path.basename(partition["device"])
+    return re.sub("[0-9]+$", "", name)
+
+
+class FstabGenerator(object):
+    def __init__(self, partitions, root_mount_point, mount_options,
+            ssd_extra_mount_options):
+        self.partitions = partitions
+        self.root_mount_point = root_mount_point
+        self.mount_options = mount_options
+        self.ssd_extra_mount_options = ssd_extra_mount_options
+        self.ssd_disks = set()
+        self.root_is_ssd = False
+
+    def run(self):
+        self.find_ssd_disks()
+        self.generate_fstab()
+        self.create_mount_points()
+        return None
+
+    def find_ssd_disks(self):
+        disks = {disk_name_for_partition(x) for x in self.partitions}
+        self.ssd_disks = {x for x in disks if is_ssd_disk(x)}
+
+    def generate_fstab(self):
+        # Create fstab
+        mkdir_p(os.path.join(self.root_mount_point, "etc"))
+        fstab_path = os.path.join(self.root_mount_point, "etc", "fstab")
+        with open(fstab_path, "w") as fl:
+            print(HEADER, file=fl)
+            for partition in self.partitions:
+                dct = self.generate_fstab_line_info(partition)
+                if dct:
+                    self.print_fstab_line(dct, file=fl)
+
+            if self.root_is_ssd:
+                # Mount /tmp on a tmpfs
+                dct = dict(
+                    device="tmpfs",
+                    mount_point="/tmp",
+                    fs="tmpfs",
+                    options="defaults,noatime,mode=1777",
+                    check=0,
+                    )
+                self.print_fstab_line(dct, file=fl)
+
+    def generate_fstab_line_info(self, partition):
         fs = partition["fs"]
         mount_point = partition["mountPoint"]
+        disk_name = disk_name_for_partition(partition)
+        is_ssd = disk_name in self.ssd_disks
 
         fs = FS_MAP.get(fs, fs)
 
         if not mount_point and not fs == "swap":
-        return
+            return None
 
-    options = "defaults"
+        options = self.mount_options.get(fs, self.mount_options["default"])
+        if is_ssd:
+            extra = self.ssd_extra_mount_options.get(fs)
+            if extra:
+                options += "," + extra
 
         if mount_point == "/":
             check = 1
@@ -59,31 +123,39 @@ def generate_fstab_line(partition):
         else:
             check = 0
 
-    return "UUID={} {:<14} {:<7} {:<10} 0       {}".format(
-        partition["uuid"],
-        mount_point or "none",
-        fs,
-        options,
-        check)
+        if mount_point == "/":
+            self.root_is_ssd = is_ssd
 
+        return dict(
+            device="UUID=" + partition["uuid"],
+            mount_point=mount_point or "none",
+            fs=fs,
+            options=options,
+            check=check)
+
+    def print_fstab_line(self, dct, file=None):
+        line = "{:41} {:<14} {:<7} {:<10} 0       {}".format(
+            dct["device"],
+            dct["mount_point"],
+            dct["fs"],
+            dct["options"],
+            dct["check"])
+        print(line, file=file)
+
+    def create_mount_points(self):
+        for partition in self.partitions:
+            if partition["mountPoint"]:
+                mkdir_p(self.root_mount_point + partition["mountPoint"])
 
 def run():
-    partitions = libcalamares.globalstorage.value("partitions")
-    root_mount_point = libcalamares.globalstorage.value("rootMountPoint")
+    gs = libcalamares.globalstorage
+    conf = libcalamares.job.configuration
+    partitions = gs.value("partitions")
+    root_mount_point = gs.value("rootMountPoint")
 
-    # Create fstab
-    mkdir_p(os.path.join(root_mount_point, "etc"))
-    fstab_path = os.path.join(root_mount_point, "etc", "fstab")
-    with open(fstab_path, "w") as fl:
-        print(HEADER, file=fl)
-        for partition in partitions:
-            line = generate_fstab_line(partition)
-            if line:
-                print(line, file=fl)
+    mount_options = conf["mountOptions"]
+    ssd_extra_mount_options = conf.get("ssdExtraMountOptions", {})
 
-    # Create mount points
-    for partition in partitions:
-        if partition["mountPoint"]:
-            mkdir_p(root_mount_point + partition["mountPoint"])
-
-    return None
+    generator = FstabGenerator(partitions, root_mount_point,
+        mount_options, ssd_extra_mount_options)
+    return generator.run()

src/modules/fstab/module.conf

@@ -4,3 +4,12 @@ interface:  "python"
 requires:   []
 script:     "main.py"
 configuration:
+    mountOptions:
+        default: defaults,noatime
+        btrfs: defaults,noatime,space_cache,autodefrag
+    ssdExtraMountOptions:
+        ext4: discard
+        jfs: discard
+        xfs: discard
+        swap: discard
+        btrfs: discard,compress=lzo