Merge pull request #3875 from MichaelEischer/fix-fuse-context-cancel

mount: Fix input/output errors for canceled syscalls
This commit is contained in:
Michael Eischer 2022-09-10 23:20:29 +02:00 committed by GitHub
commit be9ccc186e
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7 changed files with 41 additions and 19 deletions

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@ -0,0 +1,11 @@
Bugfix: Improve handling of interrupted syscalls in `mount` command
Accessing restic's fuse mount could result in "input / output" errors when
using programs in which syscalls can be interrupted. This is for example the
case for go programs.
We have corrected the error handling for interrupted syscalls.
https://github.com/restic/restic/issues/3567
https://github.com/restic/restic/issues/3694
https://github.com/restic/restic/pull/3875

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@ -5,6 +5,7 @@ package fuse
import (
"context"
"errors"
"os"
"path/filepath"
"sync"
@ -33,7 +34,7 @@ func cleanupNodeName(name string) string {
return filepath.Base(name)
}
func newDir(ctx context.Context, root *Root, inode, parentInode uint64, node *restic.Node) (*dir, error) {
func newDir(root *Root, inode, parentInode uint64, node *restic.Node) (*dir, error) {
debug.Log("new dir for %v (%v)", node.Name, node.Subtree)
return &dir{
@ -44,6 +45,16 @@ func newDir(ctx context.Context, root *Root, inode, parentInode uint64, node *re
}, nil
}
// returing a wrapped context.Canceled error will instead result in returing
// an input / output error to the user. Thus unwrap the error to match the
// expectations of bazil/fuse
func unwrapCtxCanceled(err error) error {
if errors.Is(err, context.Canceled) {
return context.Canceled
}
return err
}
// replaceSpecialNodes replaces nodes with name "." and "/" by their contents.
// Otherwise, the node is returned.
func replaceSpecialNodes(ctx context.Context, repo restic.Repository, node *restic.Node) ([]*restic.Node, error) {
@ -57,13 +68,13 @@ func replaceSpecialNodes(ctx context.Context, repo restic.Repository, node *rest
tree, err := restic.LoadTree(ctx, repo, *node.Subtree)
if err != nil {
return nil, err
return nil, unwrapCtxCanceled(err)
}
return tree.Nodes, nil
}
func newDirFromSnapshot(ctx context.Context, root *Root, inode uint64, snapshot *restic.Snapshot) (*dir, error) {
func newDirFromSnapshot(root *Root, inode uint64, snapshot *restic.Snapshot) (*dir, error) {
debug.Log("new dir for snapshot %v (%v)", snapshot.ID(), snapshot.Tree)
return &dir{
root: root,
@ -91,7 +102,7 @@ func (d *dir) open(ctx context.Context) error {
tree, err := restic.LoadTree(ctx, d.root.repo, *d.node.Subtree)
if err != nil {
debug.Log(" error loading tree %v: %v", d.node.Subtree, err)
return err
return unwrapCtxCanceled(err)
}
items := make(map[string]*restic.Node)
for _, n := range tree.Nodes {
@ -195,13 +206,13 @@ func (d *dir) Lookup(ctx context.Context, name string) (fs.Node, error) {
}
switch node.Type {
case "dir":
return newDir(ctx, d.root, fs.GenerateDynamicInode(d.inode, name), d.inode, node)
return newDir(d.root, fs.GenerateDynamicInode(d.inode, name), d.inode, node)
case "file":
return newFile(ctx, d.root, fs.GenerateDynamicInode(d.inode, name), node)
return newFile(d.root, fs.GenerateDynamicInode(d.inode, name), node)
case "symlink":
return newLink(ctx, d.root, fs.GenerateDynamicInode(d.inode, name), node)
return newLink(d.root, fs.GenerateDynamicInode(d.inode, name), node)
case "dev", "chardev", "fifo", "socket":
return newOther(ctx, d.root, fs.GenerateDynamicInode(d.inode, name), node)
return newOther(d.root, fs.GenerateDynamicInode(d.inode, name), node)
default:
debug.Log(" node %v has unknown type %v", name, node.Type)
return nil, fuse.ENOENT

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@ -36,7 +36,7 @@ type openFile struct {
cumsize []uint64
}
func newFile(ctx context.Context, root *Root, inode uint64, node *restic.Node) (fusefile *file, err error) {
func newFile(root *Root, inode uint64, node *restic.Node) (fusefile *file, err error) {
debug.Log("create new file for %v with %d blobs", node.Name, len(node.Content))
return &file{
inode: inode,
@ -105,7 +105,7 @@ func (f *openFile) getBlobAt(ctx context.Context, i int) (blob []byte, err error
blob, err = f.root.repo.LoadBlob(ctx, restic.DataBlob, f.node.Content[i], nil)
if err != nil {
debug.Log("LoadBlob(%v, %v) failed: %v", f.node.Name, f.node.Content[i], err)
return nil, err
return nil, unwrapCtxCanceled(err)
}
f.root.blobCache.Add(f.node.Content[i], blob)

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@ -119,7 +119,7 @@ func TestFuseFile(t *testing.T) {
root := &Root{repo: repo, blobCache: bloblru.New(blobCacheSize)}
inode := fs.GenerateDynamicInode(1, "foo")
f, err := newFile(context.TODO(), root, inode, node)
f, err := newFile(root, inode, node)
rtest.OK(t, err)
of, err := f.Open(context.TODO(), nil, nil)
rtest.OK(t, err)
@ -163,7 +163,7 @@ func TestFuseDir(t *testing.T) {
}
parentInode := fs.GenerateDynamicInode(0, "parent")
inode := fs.GenerateDynamicInode(1, "foo")
d, err := newDir(context.TODO(), root, inode, parentInode, node)
d, err := newDir(root, inode, parentInode, node)
rtest.OK(t, err)
// don't open the directory as that would require setting up a proper tree blob

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@ -20,7 +20,7 @@ type link struct {
inode uint64
}
func newLink(ctx context.Context, root *Root, inode uint64, node *restic.Node) (*link, error) {
func newLink(root *Root, inode uint64, node *restic.Node) (*link, error) {
return &link{root: root, inode: inode, node: node}, nil
}

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@ -16,7 +16,7 @@ type other struct {
inode uint64
}
func newOther(ctx context.Context, root *Root, inode uint64, node *restic.Node) (*other, error) {
func newOther(root *Root, inode uint64, node *restic.Node) (*other, error) {
return &other{root: root, inode: inode, node: node}, nil
}

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@ -58,7 +58,7 @@ func (d *SnapshotsDir) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
// update snapshots
meta, err := d.dirStruct.UpdatePrefix(ctx, d.prefix)
if err != nil {
return nil, err
return nil, unwrapCtxCanceled(err)
} else if meta == nil {
return nil, fuse.ENOENT
}
@ -97,7 +97,7 @@ func (d *SnapshotsDir) Lookup(ctx context.Context, name string) (fs.Node, error)
meta, err := d.dirStruct.UpdatePrefix(ctx, d.prefix)
if err != nil {
return nil, err
return nil, unwrapCtxCanceled(err)
} else if meta == nil {
return nil, fuse.ENOENT
}
@ -105,9 +105,9 @@ func (d *SnapshotsDir) Lookup(ctx context.Context, name string) (fs.Node, error)
entry := meta.names[name]
if entry != nil {
if entry.linkTarget != "" {
return newSnapshotLink(ctx, d.root, fs.GenerateDynamicInode(d.inode, name), entry.linkTarget, entry.snapshot)
return newSnapshotLink(d.root, fs.GenerateDynamicInode(d.inode, name), entry.linkTarget, entry.snapshot)
} else if entry.snapshot != nil {
return newDirFromSnapshot(ctx, d.root, fs.GenerateDynamicInode(d.inode, name), entry.snapshot)
return newDirFromSnapshot(d.root, fs.GenerateDynamicInode(d.inode, name), entry.snapshot)
} else {
return NewSnapshotsDir(d.root, fs.GenerateDynamicInode(d.inode, name), d.inode, d.dirStruct, d.prefix+"/"+name), nil
}
@ -127,7 +127,7 @@ type snapshotLink struct {
var _ = fs.NodeReadlinker(&snapshotLink{})
// newSnapshotLink
func newSnapshotLink(ctx context.Context, root *Root, inode uint64, target string, snapshot *restic.Snapshot) (*snapshotLink, error) {
func newSnapshotLink(root *Root, inode uint64, target string, snapshot *restic.Snapshot) (*snapshotLink, error) {
return &snapshotLink{root: root, inode: inode, target: target, snapshot: snapshot}, nil
}