diff options
Diffstat (limited to 'filesystem')
| -rw-r--r-- | filesystem/mountpoint.go | 47 | ||||
| -rw-r--r-- | filesystem/mountpoint_test.go | 6 |
2 files changed, 32 insertions, 21 deletions
diff --git a/filesystem/mountpoint.go b/filesystem/mountpoint.go index 1f518ec..a4c1ec1 100644 --- a/filesystem/mountpoint.go +++ b/filesystem/mountpoint.go @@ -38,13 +38,15 @@ import ( ) var ( - // This map holds data about the state of the system's filesystems. + // These maps hold data about the state of the system's filesystems. // - // It only contains one Mount per filesystem, even if there are + // They only contain one Mount per filesystem, even if there are // additional bind mounts, since we want to store fscrypt metadata in - // only one place per filesystem. If it is ambiguous which Mount should - // be used, an explicit nil entry is stored. + // only one place per filesystem. When it is ambiguous which Mount + // should be used for a filesystem, mountsByDevice will contain an + // explicit nil entry, and mountsByPath won't contain an entry. mountsByDevice map[DeviceNumber]*Mount + mountsByPath map[string]*Mount // Used to make the mount functions thread safe mountMutex sync.Mutex // True if the maps have been successfully initialized. @@ -197,18 +199,18 @@ func findMainMount(filesystemMounts []*Mount) *Mount { // since non-last mounts were already excluded earlier. // // Also build the set of all mounted subtrees. - mountsByPath := make(map[string]*mountpointTreeNode) + filesystemMountsByPath := make(map[string]*mountpointTreeNode) allSubtrees := make(map[string]bool) for _, mnt := range filesystemMounts { - mountsByPath[mnt.Path] = &mountpointTreeNode{mount: mnt} + filesystemMountsByPath[mnt.Path] = &mountpointTreeNode{mount: mnt} allSubtrees[mnt.Subtree] = true } // Divide the mounts into non-overlapping trees of mountpoints. - for path, mntNode := range mountsByPath { + for path, mntNode := range filesystemMountsByPath { for path != "/" && mntNode.parent == nil { path = filepath.Dir(path) - if parent := mountsByPath[path]; parent != nil { + if parent := filesystemMountsByPath[path]; parent != nil { mntNode.parent = parent parent.children = append(parent.children, mntNode) } @@ -233,7 +235,7 @@ func findMainMount(filesystemMounts []*Mount) *Mount { // *all* mounted subtrees. Equivalently, select a mountpoint tree in // which every uncontained subtree is mounted. var mainMount *Mount - for _, mntNode := range mountsByPath { + for _, mntNode := range filesystemMountsByPath { mnt := mntNode.mount if mntNode.parent != nil { continue @@ -260,8 +262,10 @@ func findMainMount(filesystemMounts []*Mount) *Mount { // This is separate from loadMountInfo() only for unit testing. func readMountInfo(r io.Reader) error { - mountsByPath := make(map[string]*Mount) mountsByDevice = make(map[DeviceNumber]*Mount) + mountsByPath = make(map[string]*Mount) + allMountsByDevice := make(map[DeviceNumber][]*Mount) + allMountsByPath := make(map[string]*Mount) scanner := bufio.NewScanner(r) for scanner.Scan() { @@ -281,19 +285,22 @@ func readMountInfo(r io.Reader) error { // Note this overrides the info if we have seen the mountpoint // earlier in the file. This is correct behavior because the // mountpoints are listed in mount order. - mountsByPath[mnt.Path] = mnt + allMountsByPath[mnt.Path] = mnt } // For each filesystem, choose a "main" Mount and discard any additional // bind mounts. fscrypt only cares about the main Mount, since it's - // where the fscrypt metadata is stored. Store all main Mounts in - // mountsByDevice so that they can be found by device number later. - allMountsByDevice := make(map[DeviceNumber][]*Mount) - for _, mnt := range mountsByPath { + // where the fscrypt metadata is stored. Store all the main Mounts in + // mountsByDevice and mountsByPath so that they can be found later. + for _, mnt := range allMountsByPath { allMountsByDevice[mnt.DeviceNumber] = append(allMountsByDevice[mnt.DeviceNumber], mnt) } for deviceNumber, filesystemMounts := range allMountsByDevice { - mountsByDevice[deviceNumber] = findMainMount(filesystemMounts) + mnt := findMainMount(filesystemMounts) + mountsByDevice[deviceNumber] = mnt // may store an explicit nil entry + if mnt != nil { + mountsByPath[mnt.Path] = mnt + } } return nil } @@ -329,11 +336,9 @@ func AllFilesystems() ([]*Mount, error) { return nil, err } - mounts := make([]*Mount, 0, len(mountsByDevice)) - for _, mount := range mountsByDevice { - if mount != nil { - mounts = append(mounts, mount) - } + mounts := make([]*Mount, 0, len(mountsByPath)) + for _, mount := range mountsByPath { + mounts = append(mounts, mount) } sort.Sort(PathSorter(mounts)) diff --git a/filesystem/mountpoint_test.go b/filesystem/mountpoint_test.go index 6600d87..a4688ed 100644 --- a/filesystem/mountpoint_test.go +++ b/filesystem/mountpoint_test.go @@ -90,6 +90,12 @@ func TestLoadMountInfoBasic(t *testing.T) { if mnt.ReadOnly { t.Error("Wrong readonly flag") } + if len(mountsByPath) != 1 { + t.Error("mountsByPath doesn't contain exactly one entry") + } + if mountsByPath[mnt.Path] != mnt { + t.Error("mountsByPath doesn't contain the correct entry") + } } // Test that Mount.Device is set to the mountpoint's source device if |