Handle special mount filtering at a higher level.

closes #2743

src/NzbDrone.Common/Disk/DiskProviderBase.cs

@@ -418,7 +418,12 @@ namespace NzbDrone.Common.Disk
             return new FileStream(path, FileMode.Create);
         }
 
-        public virtual List<IMount> GetMounts()
+        public List<IMount> GetMounts()
+        {
+            return GetAllMounts().Where(d => !IsSpecialMount(d)).ToList();
+        }
+
+        protected virtual List<IMount> GetAllMounts()
         {
             return GetDriveInfoMounts().Where(d => d.DriveType == DriveType.Fixed || d.DriveType == DriveType.Network || d.DriveType == DriveType.Removable)
                                        .Select(d => new DriveInfoMount(d))
@@ -426,11 +431,16 @@ namespace NzbDrone.Common.Disk
                                        .ToList();
         }
 
+        protected virtual bool IsSpecialMount(IMount mount)
+        {
+            return false;
+        }
+
         public virtual IMount GetMount(string path)
         {
             try
             {
-                var mounts = GetMounts();
+                var mounts = GetAllMounts();
 
                 return mounts.Where(drive => drive.RootDirectory.PathEquals(path) ||
                                              drive.RootDirectory.IsParentPath(path))

src/NzbDrone.Mono.Test/DiskProviderTests/DiskProviderFixture.cs

@@ -1,8 +1,11 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using FluentAssertions;
 using Mono.Unix;
 using NUnit.Framework;
+using NzbDrone.Common.Disk;
 using NzbDrone.Common.Test.DiskTests;
 using NzbDrone.Mono.Disk;
 
@@ -87,5 +90,37 @@ namespace NzbDrone.Mono.Test.DiskProviderTests
             File.ReadAllText(source).Should().Be("Some content");
             File.ReadAllText(destination).Should().Be("Some content");
         }
+
+        private void GivenSpecialMount(string rootDir)
+        {
+            Mocker.GetMock<IProcMountProvider>()
+                .Setup(v => v.GetMounts())
+                .Returns(new List<IMount> {
+                    new ProcMount(DriveType.Fixed, rootDir, rootDir, "myfs", new MountOptions(new Dictionary<string, string>()))
+                });
+        }
+
+        [TestCase("/snap/blaat")]
+        [TestCase("/var/lib/docker/zfs-storage-mount")]
+        public void should_ignore_special_mounts(string rootDir)
+        {
+            GivenSpecialMount(rootDir);
+
+            var mounts = Subject.GetMounts();
+
+            mounts.Select(d => d.RootDirectory).Should().NotContain(rootDir);
+        }
+
+        [TestCase("/snap/blaat")]
+        [TestCase("/var/lib/docker/zfs-storage-moun")]
+        public void should_return_special_mount_when_queried(string rootDir)
+        {
+            GivenSpecialMount(rootDir);
+
+            var mount = Subject.GetMount(Path.Combine(rootDir, "dir/somefile.mkv"));
+
+            mount.Should().NotBeNull();
+            mount.RootDirectory.Should().Be(rootDir);
+        }
     }
 }

src/NzbDrone.Mono/Disk/DiskProvider.cs

@@ -75,7 +75,7 @@ namespace NzbDrone.Mono.Disk
             SetOwner(path, user, group);
         }
 
-        public override List<IMount> GetMounts()
+        protected override List<IMount> GetAllMounts()
         {
             return _procMountProvider.GetMounts()
                                      .Concat(GetDriveInfoMounts()
@@ -87,6 +87,25 @@ namespace NzbDrone.Mono.Disk
                                      .ToList();
         }
 
+        protected override bool IsSpecialMount(IMount mount)
+        {
+            var root = mount.RootDirectory;
+
+            if (root.StartsWith("/var/lib/"))
+            {
+                // Could be /var/lib/docker when docker uses zfs. Very unlikely that a useful mount is located in /var/lib.
+                return true;
+            }
+
+            if (root.StartsWith("/snap/"))
+            {
+                // Mount point for snap packages
+                return true;
+            }
+
+            return false;
+        }
+
         public override long? GetTotalSize(string path)
         {
             Ensure.That(path, () => path).IsValidPath();

src/NzbDrone.Mono/Disk/ProcMountProvider.cs

@@ -111,18 +111,6 @@ namespace NzbDrone.Mono.Disk
                 return null;
             }
 
-            if (mount.StartsWith("/var/lib/"))
-            {
-                // Could be /var/lib/docker when docker uses zfs. Very unlikely that a useful mount is located in /var/lib.
-                return null;
-            }
-
-            if (mount.StartsWith("/snap/"))
-            {
-                // Mount point for snap packages
-                return null;
-            }
-
             var driveType = FindDriveType.Find(type);
 
             if (name.StartsWith("/dev/") || GetFileSystems().GetValueOrDefault(type, false))