Implement "repo rm-root" command to unlink the files API root.

cmd/ipfs/ipfs.go

@@ -84,13 +84,14 @@ func (d *cmdDetails) usesRepo() bool          { return !d.doesNotUseRepo }
 // properties so that other code can make decisions about whether to invoke a
 // command or return an error to the user.
 var cmdDetailsMap = map[string]cmdDetails{
-	"init":        {doesNotUseConfigAsInput: true, cannotRunOnDaemon: true, doesNotUseRepo: true},
-	"daemon":      {doesNotUseConfigAsInput: true, cannotRunOnDaemon: true},
-	"commands":    {doesNotUseRepo: true},
-	"version":     {doesNotUseConfigAsInput: true, doesNotUseRepo: true}, // must be permitted to run before init
-	"log":         {cannotRunOnClient: true},
-	"diag/cmds":   {cannotRunOnClient: true},
-	"repo/fsck":   {cannotRunOnDaemon: true},
-	"config/edit": {cannotRunOnDaemon: true, doesNotUseRepo: true},
-	"cid":         {doesNotUseRepo: true},
+	"init":               {doesNotUseConfigAsInput: true, cannotRunOnDaemon: true, doesNotUseRepo: true},
+	"daemon":             {doesNotUseConfigAsInput: true, cannotRunOnDaemon: true},
+	"commands":           {doesNotUseRepo: true},
+	"version":            {doesNotUseConfigAsInput: true, doesNotUseRepo: true}, // must be permitted to run before init
+	"log":                {cannotRunOnClient: true},
+	"diag/cmds":          {cannotRunOnClient: true},
+	"repo/fsck":          {cannotRunOnDaemon: true},
+	"repo/rm-files-root": {cannotRunOnDaemon: true},
+	"config/edit":        {cannotRunOnDaemon: true, doesNotUseRepo: true},
+	"cid":                {doesNotUseRepo: true},
 }

core/commands/commands_test.go

@@ -188,6 +188,7 @@ func TestCommands(t *testing.T) {
 		"/repo/stat",
 		"/repo/verify",
 		"/repo/version",
+		"/repo/rm-files-root",
 		"/resolve",
 		"/shutdown",
 		"/stats",

core/commands/repo.go

@@ -12,13 +12,16 @@ import (
 	"sync"
 	"text/tabwriter"
 
+	core "github.com/ipfs/go-ipfs/core"
 	cmdenv "github.com/ipfs/go-ipfs/core/commands/cmdenv"
 	corerepo "github.com/ipfs/go-ipfs/core/corerepo"
 	fsrepo "github.com/ipfs/go-ipfs/repo/fsrepo"
 
 	cmds "gx/ipfs/QmQkW9fnCsg9SLHdViiAh6qfBppodsPZVpU92dZLqYtEfs/go-ipfs-cmds"
 	cid "gx/ipfs/QmTbxNB1NwDesLmKTscr4udL2tVP7MaxvXnD1D9yX7g3PN/go-cid"
 	config "gx/ipfs/QmUAuYuiafnJRZxDDX7MuruMNsicYNuyub5vUeAcupUBNs/go-ipfs-config"
+	ds "gx/ipfs/QmUadX5EcvrBmxAV9sE7wUWtWSqxns5K84qKJBixmcT1w9/go-datastore"
+	b58 "gx/ipfs/QmWFAMPqsEyUX7gDUsRVmMWz59FxSpJ1b2v6bJ1yYzo7jY/go-base58-fast/base58"
 	bstore "gx/ipfs/QmXjKkjMDTtXAiLBwstVexofB8LeruZmE2eBd85GwGFFLA/go-ipfs-blockstore"
 	cmdkit "gx/ipfs/Qmde5VP1qUkyQXKCfmEUA7bP64V2HAptbJ7phuPp7jXWwg/go-ipfs-cmdkit"
 )
@@ -36,11 +39,12 @@ var RepoCmd = &cmds.Command{
 	},
 
 	Subcommands: map[string]*cmds.Command{
-		"stat":    repoStatCmd,
-		"gc":      repoGcCmd,
-		"fsck":    repoFsckCmd,
-		"version": repoVersionCmd,
-		"verify":  repoVerifyCmd,
+		"stat":          repoStatCmd,
+		"gc":            repoGcCmd,
+		"fsck":          repoFsckCmd,
+		"version":       repoVersionCmd,
+		"verify":        repoVerifyCmd,
+		"rm-files-root": repoRmFilesRootCmd,
 	},
 }
 
@@ -262,6 +266,89 @@ daemons are running.
 	},
 }
 
+var repoRmFilesRootCmd = &cmds.Command{
+	Helptext: cmdkit.HelpText{
+		Tagline: "Unlink the root used by the `ipfs files` comands.",
+		ShortDescription: `
+'ipfs repo rm-files-root' will unlink the root used by the files API ('ipfs
+files' commands) without trying to read the root itself.  The root and
+its children will be removed the next time the garbage collector runs,
+unless pinned.
+
+This command is designed to recover form the situation when the root
+becomes unavailable and recovering it (such as recreating it, or
+fetching it from the network) is not possible.  This command should
+only be used as a last resort as using this command could lead to data
+loss if there are unpinned nodes connected to the root.
+
+This command can only run when the ipfs daemon is not running.
+`,
+	},
+	Options: []cmdkit.Option{
+		cmdkit.BoolOption("confirm", "Really perform operation."),
+		cmdkit.BoolOption("remove-existing-root", "Remove even if it root exists locally."),
+	},
+	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
+		confirm, _ := req.Options["confirm"].(bool)
+		removeExistingRoot, _ := req.Options["remove-existing-root"].(bool)
+
+		if !confirm {
+			return fmt.Errorf("this is a potentially dangerous operation please pass --confirm to proceed")
+		}
+
+		configRoot, err := cmdenv.GetConfigRoot(env)
+		if err != nil {
+			return err
+		}
+
+		// Can't use a full node as that interferes with the removal
+		// of the files root, so open the repo directly
+		repo, err := fsrepo.Open(configRoot)
+		if err != nil {
+			return err
+		}
+		defer repo.Close()
+		bs := bstore.NewBlockstore(repo.Datastore())
+
+		// Get the old root and display it to the user so that they can
+		// can do something to prevent from being garbage collected,
+		// such as pin it
+		val, err := repo.Datastore().Get(core.FilesRootKey)
+		if err == ds.ErrNotFound || val == nil {
+			return cmds.EmitOnce(res, &MessageOutput{"`ipfs files` root not found.\n"})
+		}
+
+		var cidStr string
+		var have bool
+		c, err := cid.Cast(val)
+		if err == nil {
+			cidStr = c.String()
+			have, _ = bs.Has(c)
+		} else {
+			cidStr = b58.Encode(val)
+		}
+
+		if have && !removeExistingRoot {
+			return fmt.Errorf("`ipfs files` root %s exists locally. Are you sure you want to unlink this? Pass --remove-existing-root to continue", cidStr)
+		}
+
+		err = repo.Datastore().Delete(core.FilesRootKey)
+		if err != nil {
+			return fmt.Errorf("unable to remove `ipfs files` root: %s.  Root hash was %s", err.Error(), cidStr)
+		}
+		return cmds.EmitOnce(res, &MessageOutput{
+			fmt.Sprintf("Unlinked files API root.  Root hash was %s.\n", cidStr),
+		})
+	},
+	Type: MessageOutput{},
+	Encoders: cmds.EncoderMap{
+		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, msg *MessageOutput) error {
+			_, err := fmt.Fprintf(w, "%s", msg.Message)
+			return err
+		}),
+	},
+}
+
 type VerifyProgress struct {
 	Msg      string
 	Progress int

core/core.go

@@ -80,6 +80,9 @@ import (
 
 const IpnsValidatorTag = "ipns"
 
+// FilesRootKey is the datastore key for the files root.
+var FilesRootKey ds.Key = ds.NewKey("/local/filesroot")
+
 const kReprovideFrequency = time.Hour * 12
 const discoveryConnTimeout = time.Second * 30
 const DefaultIpnsCacheSize = 128
@@ -856,13 +859,12 @@ func (n *IpfsNode) loadBootstrapPeers() ([]pstore.PeerInfo, error) {
 }
 
 func (n *IpfsNode) loadFilesRoot() error {
-	dsk := ds.NewKey("/local/filesroot")
 	pf := func(ctx context.Context, c cid.Cid) error {
-		return n.Repo.Datastore().Put(dsk, c.Bytes())
+		return n.Repo.Datastore().Put(FilesRootKey, c.Bytes())
 	}
 
 	var nd *merkledag.ProtoNode
-	val, err := n.Repo.Datastore().Get(dsk)
+	val, err := n.Repo.Datastore().Get(FilesRootKey)
 
 	switch {
 	case err == ds.ErrNotFound || val == nil:

test/sharness/t0089-repo-rm-files-root.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2016 Jeromy Johnson
+# MIT Licensed; see the LICENSE file in this repository.
+#
+
+test_description="Test ipfs repo fsck"
+
+. lib/test-lib.sh
+
+test_init_ipfs
+
+ROOT_HASH=QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn
+
+test_expect_success "ipfs repo rm-files-root fails without --confirm" '
+  test_must_fail ipfs repo rm-files-root 2> err &&
+  cat err &&
+  fgrep -q "please pass --confirm to proceed" err
+'
+
+test_expect_success "ipfs repo rm-files-root fails to remove existing root without --remove-existing-root" '
+  test_must_fail ipfs repo rm-files-root --confirm 2> err &&
+  cat err &&
+  fgrep -q "Are you sure you want to unlink this?" err
+'
+
+test_expect_success "ipfs repo rm-files-root" '
+  ipfs repo rm-files-root --confirm --remove-existing-root | tee rm-files-root.actual &&
+  echo "Unlinked files API root.  Root hash was $ROOT_HASH." > rm-files-root.expected &&
+  test_cmp rm-files-root.expected rm-files-root.actual
+'
+
+test_expect_success "files api root really removed" '
+  ipfs repo rm-files-root --confirm | tee rm-files-root-post.actual &&
+  echo "Files API root not found." > rm-files-root-post.expected &&
+  test_cmp rm-files-root-post.expected rm-files-root-post.actual
+'
+
+test_launch_ipfs_daemon
+
+test_expect_success "ipfs repo rm-files-root does not run on daemon" '
+  test_must_fail ipfs repo rm-files-root --confirm 2> err &&
+  cat err &&
+  fgrep -q "ipfs daemon is running" err
+'
+
+test_kill_ipfs_daemon
+
+test_done