ipfs: all - fix ReadDir deadlock on EOF/error state

Originally, directory streams were struct values, and a channel field
was used to validate if the file was open / not-yet-closed.
Eventually, that was changed to be a pointer to struct, which was used
as a check condition instead. This invalidator path was never removed,
and causes deadlocks if the caller tries to read from a directory which
already encountered an error (either `EOF` or any other).

Author: djdv

internal/filesystem/ipfs/ipfs.go

@@ -499,7 +499,6 @@ func (id *ipfsDirectory) ReadDir(count int) ([]fs.DirEntry, error) {
 	)
 	entries, err := readEntries(ctx, entryChan, count)
 	if err != nil {
-		stream.ch = nil
 		err = readdirErr(op, id.info.name, err)
 		id.err = err
 	}

internal/filesystem/ipfs/keyfs.go

@@ -203,7 +203,6 @@ func (kd *keyDirectory) ReadDir(count int) ([]fs.DirEntry, error) {
 	}
 	ents, err := readEntries(ctx, entries, count)
 	if err != nil {
-		stream.ch = nil
 		err = readdirErr(op, filesystem.Root, err)
 		kd.err = err
 	}

internal/filesystem/ipfs/pinfs.go

@@ -293,7 +293,6 @@ func (pd *pinDirectory) ReadDir(count int) ([]fs.DirEntry, error) {
 	)
 	entries, err := readEntries(ctx, entryChan, count)
 	if err != nil {
-		stream.ch = nil
 		err = readdirErr(op, filesystem.Root, err)
 		pd.err = err
 	}