Have a go at rearranging things in to a lib/btrfsprogs

3 files changed, 4 insertions, 419 deletions

diff --git a/cmd/btrfs-mount/fuseutil.go b/cmd/btrfs-mount/fuseutil.go
deleted file mode 100644
index 940e571..0000000
--- a/cmd/btrfs-mount/fuseutil.go
+++ /dev/null
@@ -1,56 +0,0 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-package main
-
-import (
-	"context"
-	"sync/atomic"
-
-	"github.com/datawire/dlib/dcontext"
-	"github.com/datawire/dlib/dgroup"
-	"github.com/datawire/dlib/dlog"
-	"github.com/jacobsa/fuse"
-)
-
-func Mount(ctx context.Context, mountpoint string, server fuse.Server, cfg *fuse.MountConfig) error {
-	grp := dgroup.NewGroup(ctx, dgroup.GroupConfig{
-		// Allow mountHandle.Join() returning to cause the
-		// "unmount" goroutine to quit.
-		ShutdownOnNonError: true,
-	})
-	mounted := uint32(1)
-	grp.Go("unmount", func(ctx context.Context) error {
-		<-ctx.Done()
-		var err error
-		var gotNil bool
-		// Keep retrying, because the FS might be busy.
-		for atomic.LoadUint32(&mounted) != 0 {
-			if _err := fuse.Unmount(mountpoint); _err == nil {
-				gotNil = true
-			} else if !gotNil {
-				err = _err
-			}
-		}
-		if gotNil {
-			return nil
-		}
-		return err
-	})
-	grp.Go("mount", func(ctx context.Context) error {
-		defer atomic.StoreUint32(&mounted, 0)
-
-		cfg.OpContext = ctx
-		cfg.ErrorLogger = dlog.StdLogger(ctx, dlog.LogLevelError)
-		cfg.DebugLogger = dlog.StdLogger(ctx, dlog.LogLevelDebug)
-
-		mountHandle, err := fuse.Mount(mountpoint, server, cfg)
-		if err != nil {
-			return err
-		}
-		dlog.Infof(ctx, "mounted %q", mountpoint)
-		return mountHandle.Join(dcontext.HardContext(ctx))
-	})
-	return grp.Wait()
-}
diff --git a/cmd/btrfs-mount/main.go b/cmd/btrfs-mount/main.go
index 0183c02..7debb3a 100644
--- a/cmd/btrfs-mount/main.go
+++ b/cmd/btrfs-mount/main.go
@@ -8,14 +8,13 @@ import (
 	"context"
 	"fmt"
 	"os"
-	"path/filepath"
 
 	"github.com/datawire/dlib/dgroup"
 	"github.com/datawire/dlib/dlog"
 	"github.com/sirupsen/logrus"
 
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfsmisc"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsinspect"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsutil"
 )
 
 func main() {
@@ -36,14 +35,6 @@ func main() {
 	}
 }
 
-func tryAbs(rel string) string {
-	abs, err := filepath.Abs(rel)
-	if err != nil {
-		return rel
-	}
-	return abs
-}
-
 func Main(ctx context.Context, mountpoint string, imgfilenames ...string) (err error) {
 	maybeSetErr := func(_err error) {
 		if _err != nil && err == nil {
@@ -51,7 +42,7 @@ func Main(ctx context.Context, mountpoint string, imgfilenames ...string) (err e
 		}
 	}
 
-	fs, err := btrfsmisc.Open(os.O_RDONLY, imgfilenames...)
+	fs, err := btrfsutil.Open(os.O_RDONLY, imgfilenames...)
 	if err != nil {
 		return err
 	}
@@ -59,13 +50,5 @@ func Main(ctx context.Context, mountpoint string, imgfilenames ...string) (err e
 		maybeSetErr(fs.Close())
 	}()
 
-	rootSubvol := &Subvolume{
-		Subvolume: btrfs.Subvolume{
-			FS:     fs,
-			TreeID: btrfs.FS_TREE_OBJECTID,
-		},
-		DeviceName: tryAbs(imgfilenames[0]),
-		Mountpoint: mountpoint,
-	}
-	return rootSubvol.Run(ctx)
+	return btrfsinspect.MountRO(ctx, fs, mountpoint)
 }
diff --git a/cmd/btrfs-mount/subvol_fuse.go b/cmd/btrfs-mount/subvol_fuse.go
deleted file mode 100644
index 8a910bf..0000000
--- a/cmd/btrfs-mount/subvol_fuse.go
+++ /dev/null
@@ -1,342 +0,0 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-package main
-
-import (
-	"context"
-	"errors"
-	"fmt"
-	"io"
-	"path/filepath"
-	"sync"
-	"sync/atomic"
-	"syscall"
-
-	"github.com/datawire/dlib/dgroup"
-	"github.com/jacobsa/fuse"
-	"github.com/jacobsa/fuse/fuseops"
-	"github.com/jacobsa/fuse/fuseutil"
-
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
-	"git.lukeshu.com/btrfs-progs-ng/lib/linux"
-	"git.lukeshu.com/btrfs-progs-ng/lib/util"
-)
-
-type dirState struct {
-	Dir *btrfs.Dir
-}
-
-type fileState struct {
-	File *btrfs.File
-}
-
-type Subvolume struct {
-	btrfs.Subvolume
-	DeviceName string
-	Mountpoint string
-
-	fuseutil.NotImplementedFileSystem
-	lastHandle  uint64
-	dirHandles  util.SyncMap[fuseops.HandleID, *dirState]
-	fileHandles util.SyncMap[fuseops.HandleID, *fileState]
-
-	subvolMu sync.Mutex
-	subvols  map[string]struct{}
-	grp      *dgroup.Group
-}
-
-func (sv *Subvolume) Run(ctx context.Context) error {
-	sv.grp = dgroup.NewGroup(ctx, dgroup.GroupConfig{})
-	sv.grp.Go("self", func(ctx context.Context) error {
-		cfg := &fuse.MountConfig{
-			FSName:  sv.DeviceName,
-			Subtype: "btrfs",
-
-			ReadOnly: true,
-
-			Options: map[string]string{
-				"allow_other": "",
-			},
-		}
-		return Mount(ctx, sv.Mountpoint, fuseutil.NewFileSystemServer(sv), cfg)
-	})
-	return sv.grp.Wait()
-}
-
-func (sv *Subvolume) newHandle() fuseops.HandleID {
-	return fuseops.HandleID(atomic.AddUint64(&sv.lastHandle, 1))
-}
-
-func inodeItemToFUSE(itemBody btrfsitem.Inode) fuseops.InodeAttributes {
-	return fuseops.InodeAttributes{
-		Size:  uint64(itemBody.Size),
-		Nlink: uint32(itemBody.NLink),
-		Mode:  uint32(itemBody.Mode),
-		//RDev: itemBody.Rdev, // jacobsa/fuse doesn't expose rdev
-		Atime: itemBody.ATime.ToStd(),
-		Mtime: itemBody.MTime.ToStd(),
-		Ctime: itemBody.CTime.ToStd(),
-		//Crtime: itemBody.OTime,
-		Uid: uint32(itemBody.UID),
-		Gid: uint32(itemBody.GID),
-	}
-}
-
-func (sv *Subvolume) LoadDir(inode btrfs.ObjID) (val *btrfs.Dir, err error) {
-	val, err = sv.Subvolume.LoadDir(inode)
-	if val != nil {
-		haveSubvolumes := false
-		for _, index := range util.SortedMapKeys(val.ChildrenByIndex) {
-			entry := val.ChildrenByIndex[index]
-			if entry.Location.ItemType == btrfsitem.ROOT_ITEM_KEY {
-				haveSubvolumes = true
-				break
-			}
-		}
-		if haveSubvolumes {
-			abspath, _err := val.AbsPath()
-			if _err != nil {
-				return
-			}
-			sv.subvolMu.Lock()
-			for _, index := range util.SortedMapKeys(val.ChildrenByIndex) {
-				entry := val.ChildrenByIndex[index]
-				if entry.Location.ItemType != btrfsitem.ROOT_ITEM_KEY {
-					continue
-				}
-				if sv.subvols == nil {
-					sv.subvols = make(map[string]struct{})
-				}
-				subMountpoint := filepath.Join(abspath, string(entry.Name))
-				if _, alreadyMounted := sv.subvols[subMountpoint]; !alreadyMounted {
-					sv.subvols[subMountpoint] = struct{}{}
-					workerName := fmt.Sprintf("%d-%s", val.Inode, filepath.Base(subMountpoint))
-					sv.grp.Go(workerName, func(ctx context.Context) error {
-						subSv := &Subvolume{
-							Subvolume: btrfs.Subvolume{
-								FS:     sv.FS,
-								TreeID: entry.Location.ObjectID,
-							},
-							DeviceName: sv.DeviceName,
-							Mountpoint: filepath.Join(sv.Mountpoint, subMountpoint[1:]),
-						}
-						return subSv.Run(ctx)
-					})
-				}
-			}
-			sv.subvolMu.Unlock()
-		}
-	}
-	return
-}
-
-func (sv *Subvolume) StatFS(_ context.Context, op *fuseops.StatFSOp) error {
-	// See linux.git/fs/btrfs/super.c:btrfs_statfs()
-	sb, err := sv.FS.Superblock()
-	if err != nil {
-		return err
-	}
-
-	op.IoSize = sb.Data.SectorSize
-	op.BlockSize = sb.Data.SectorSize
-	op.Blocks = sb.Data.TotalBytes / uint64(sb.Data.SectorSize) // TODO: adjust for RAID type
-	//op.BlocksFree = TODO
-
-	// btrfs doesn't have a fixed number of inodes
-	op.Inodes = 0
-	op.InodesFree = 0
-
-	// jacobsa/fuse doesn't expose namelen, instead hard-coding it
-	// to 255.  Which is fine by us, because that's what it is for
-	// btrfs.
-
-	return nil
-}
-
-func (sv *Subvolume) LookUpInode(_ context.Context, op *fuseops.LookUpInodeOp) error {
-	if op.Parent == fuseops.RootInodeID {
-		parent, err := sv.GetRootInode()
-		if err != nil {
-			return err
-		}
-		op.Parent = fuseops.InodeID(parent)
-	}
-
-	dir, err := sv.LoadDir(btrfs.ObjID(op.Parent))
-	if err != nil {
-		return err
-	}
-	entry, ok := dir.ChildrenByName[op.Name]
-	if !ok {
-		return syscall.ENOENT
-	}
-	if entry.Location.ItemType != btrfsitem.INODE_ITEM_KEY {
-		// Subvolume
-		//
-		// Because each subvolume has its own pool of inodes
-		// (as in 2 different subvolumes can have files with
-		// te same inode number), so to represent that to FUSE
-		// we need to have this be a full separate mountpoint.
-		//
-		// I'd want to return EIO or EINTR or something here,
-		// but both the FUSE userspace tools and the kernel
-		// itself stat the mountpoint before mounting it, so
-		// we've got to return something bogus here to let
-		// that mount happen.
-		op.Entry = fuseops.ChildInodeEntry{
-			Child: 2, // an inode number that a real file will never have
-			Attributes: fuseops.InodeAttributes{
-				Nlink: 1,
-				Mode:  uint32(linux.ModeFmtDir | 0700),
-			},
-		}
-		return nil
-	}
-	bareInode, err := sv.LoadBareInode(entry.Location.ObjectID)
-	if err != nil {
-		return err
-	}
-	op.Entry = fuseops.ChildInodeEntry{
-		Child:      fuseops.InodeID(entry.Location.ObjectID),
-		Generation: fuseops.GenerationNumber(bareInode.InodeItem.Sequence),
-		Attributes: inodeItemToFUSE(*bareInode.InodeItem),
-	}
-	return nil
-}
-
-func (sv *Subvolume) GetInodeAttributes(_ context.Context, op *fuseops.GetInodeAttributesOp) error {
-	if op.Inode == fuseops.RootInodeID {
-		inode, err := sv.GetRootInode()
-		if err != nil {
-			return err
-		}
-		op.Inode = fuseops.InodeID(inode)
-	}
-
-	bareInode, err := sv.LoadBareInode(btrfs.ObjID(op.Inode))
-	if err != nil {
-		return err
-	}
-
-	op.Attributes = inodeItemToFUSE(*bareInode.InodeItem)
-	return nil
-}
-
-func (sv *Subvolume) OpenDir(_ context.Context, op *fuseops.OpenDirOp) error {
-	if op.Inode == fuseops.RootInodeID {
-		inode, err := sv.GetRootInode()
-		if err != nil {
-			return err
-		}
-		op.Inode = fuseops.InodeID(inode)
-	}
-
-	dir, err := sv.LoadDir(btrfs.ObjID(op.Inode))
-	if err != nil {
-		return err
-	}
-	handle := sv.newHandle()
-	sv.dirHandles.Store(handle, &dirState{
-		Dir: dir,
-	})
-	op.Handle = handle
-	return nil
-}
-func (sv *Subvolume) ReadDir(_ context.Context, op *fuseops.ReadDirOp) error {
-	state, ok := sv.dirHandles.Load(op.Handle)
-	if !ok {
-		return syscall.EBADF
-	}
-	origOffset := op.Offset
-	for _, index := range util.SortedMapKeys(state.Dir.ChildrenByIndex) {
-		if index < uint64(origOffset) {
-			continue
-		}
-		entry := state.Dir.ChildrenByIndex[index]
-		n := fuseutil.WriteDirent(op.Dst[op.BytesRead:], fuseutil.Dirent{
-			Offset: fuseops.DirOffset(index + 1),
-			Inode:  fuseops.InodeID(entry.Location.ObjectID),
-			Name:   string(entry.Name),
-			Type: map[btrfsitem.FileType]fuseutil.DirentType{
-				btrfsitem.FT_UNKNOWN:  fuseutil.DT_Unknown,
-				btrfsitem.FT_REG_FILE: fuseutil.DT_File,
-				btrfsitem.FT_DIR:      fuseutil.DT_Directory,
-				btrfsitem.FT_CHRDEV:   fuseutil.DT_Char,
-				btrfsitem.FT_BLKDEV:   fuseutil.DT_Block,
-				btrfsitem.FT_FIFO:     fuseutil.DT_FIFO,
-				btrfsitem.FT_SOCK:     fuseutil.DT_Socket,
-				btrfsitem.FT_SYMLINK:  fuseutil.DT_Link,
-			}[entry.Type],
-		})
-		if n == 0 {
-			break
-		}
-		op.BytesRead += n
-	}
-	return nil
-}
-func (sv *Subvolume) ReleaseDirHandle(_ context.Context, op *fuseops.ReleaseDirHandleOp) error {
-	_, ok := sv.dirHandles.LoadAndDelete(op.Handle)
-	if !ok {
-		return syscall.EBADF
-	}
-	return nil
-}
-
-func (sv *Subvolume) OpenFile(_ context.Context, op *fuseops.OpenFileOp) error {
-	file, err := sv.LoadFile(btrfs.ObjID(op.Inode))
-	if err != nil {
-		return err
-	}
-	handle := sv.newHandle()
-	sv.fileHandles.Store(handle, &fileState{
-		File: file,
-	})
-	op.Handle = handle
-	op.KeepPageCache = true
-	return nil
-}
-func (sv *Subvolume) ReadFile(_ context.Context, op *fuseops.ReadFileOp) error {
-	state, ok := sv.fileHandles.Load(op.Handle)
-	if !ok {
-		return syscall.EBADF
-	}
-
-	var dat []byte
-	if op.Dst != nil {
-		size := util.Min(int64(len(op.Dst)), op.Size)
-		dat = op.Dst[:size]
-	} else {
-		dat = make([]byte, op.Size)
-		op.Data = [][]byte{dat}
-	}
-
-	var err error
-	op.BytesRead, err = state.File.ReadAt(dat, op.Offset)
-	if errors.Is(err, io.EOF) {
-		err = nil
-	}
-
-	return err
-}
-func (sv *Subvolume) ReleaseFileHandle(_ context.Context, op *fuseops.ReleaseFileHandleOp) error {
-	_, ok := sv.fileHandles.LoadAndDelete(op.Handle)
-	if !ok {
-		return syscall.EBADF
-	}
-	return nil
-}
-
-func (sv *Subvolume) ReadSymlink(_ context.Context, op *fuseops.ReadSymlinkOp) error {
-	return syscall.ENOSYS
-}
-
-func (sv *Subvolume) GetXattr(_ context.Context, op *fuseops.GetXattrOp) error { return syscall.ENOSYS }
-func (sv *Subvolume) ListXattr(_ context.Context, op *fuseops.ListXattrOp) error {
-	return syscall.ENOSYS
-}
-
-func (sv *Subvolume) Destroy() {}