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path: root/lib/btrfsprogs/btrfsinspect/mount.go
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Diffstat (limited to 'lib/btrfsprogs/btrfsinspect/mount.go')
-rw-r--r--lib/btrfsprogs/btrfsinspect/mount.go482
1 files changed, 0 insertions, 482 deletions
diff --git a/lib/btrfsprogs/btrfsinspect/mount.go b/lib/btrfsprogs/btrfsinspect/mount.go
deleted file mode 100644
index 0ac8497..0000000
--- a/lib/btrfsprogs/btrfsinspect/mount.go
+++ /dev/null
@@ -1,482 +0,0 @@
-// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-package btrfsinspect
-
-import (
- "context"
- "errors"
- "fmt"
- "io"
- "path/filepath"
- "sync"
- "sync/atomic"
- "syscall"
-
- "git.lukeshu.com/go/typedsync"
- "github.com/datawire/dlib/dcontext"
- "github.com/datawire/dlib/dgroup"
- "github.com/datawire/dlib/dlog"
- "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/btrfs/btrfsprim"
- "git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsutil"
- "git.lukeshu.com/btrfs-progs-ng/lib/containers"
- "git.lukeshu.com/btrfs-progs-ng/lib/maps"
- "git.lukeshu.com/btrfs-progs-ng/lib/slices"
-)
-
-func MountRO(ctx context.Context, fs *btrfs.FS, mountpoint string, noChecksums bool) error {
- pvs := fs.LV.PhysicalVolumes()
- if len(pvs) < 1 {
- return errors.New("no devices")
- }
-
- deviceName := pvs[maps.SortedKeys(pvs)[0]].Name()
- if abs, err := filepath.Abs(deviceName); err == nil {
- deviceName = abs
- }
-
- rootSubvol := &subvolume{
- Subvolume: btrfs.Subvolume{
- FS: btrfsutil.NewBrokenTrees(ctx, fs),
- TreeID: btrfsprim.FS_TREE_OBJECTID,
- NoChecksums: noChecksums,
- },
- DeviceName: deviceName,
- Mountpoint: mountpoint,
- }
- return rootSubvol.Run(ctx)
-}
-
-func fuseMount(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()
-}
-
-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 typedsync.Map[fuseops.HandleID, *dirState]
- fileHandles typedsync.Map[fuseops.HandleID, *fileState]
-
- subvolMu sync.Mutex
- subvols containers.Set[string]
- 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 fuseMount(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 btrfsprim.ObjID) (val *btrfs.Dir, err error) {
- val, err = sv.Subvolume.LoadDir(inode)
- if val != nil {
- haveSubvolumes := false
- for _, index := range maps.SortedKeys(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 val, err
- }
- sv.subvolMu.Lock()
- for _, index := range maps.SortedKeys(val.ChildrenByIndex) {
- entry := val.ChildrenByIndex[index]
- if entry.Location.ItemType != btrfsitem.ROOT_ITEM_KEY {
- continue
- }
- if sv.subvols == nil {
- sv.subvols = make(containers.Set[string])
- }
- subMountpoint := filepath.Join(abspath, string(entry.Name))
- if !sv.subvols.Has(subMountpoint) {
- sv.subvols.Insert(subMountpoint)
- 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,
- NoChecksums: sv.NoChecksums,
- },
- DeviceName: sv.DeviceName,
- Mountpoint: filepath.Join(sv.Mountpoint, subMountpoint[1:]),
- }
- return subSv.Run(ctx)
- })
- }
- }
- sv.subvolMu.Unlock()
- }
- }
- return val, err
-}
-
-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.SectorSize
- op.BlockSize = sb.SectorSize
- op.Blocks = sb.TotalBytes / uint64(sb.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(btrfsprim.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(btrfsitem.ModeFmtDir | 0o700), //nolint:gomnd // TODO
- },
- }
- 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(btrfsprim.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(btrfsprim.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 maps.SortedKeys(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(btrfsprim.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 := slices.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 {
- file, err := sv.LoadFile(btrfsprim.ObjID(op.Inode))
- if err != nil {
- return err
- }
- reader := io.NewSectionReader(file, 0, file.InodeItem.Size)
- tgt, err := io.ReadAll(reader)
- if err != nil {
- return err
- }
- op.Target = string(tgt)
- return nil
-}
-
-func (sv *subvolume) ListXattr(_ context.Context, op *fuseops.ListXattrOp) error {
- if op.Inode == fuseops.RootInodeID {
- inode, err := sv.GetRootInode()
- if err != nil {
- return err
- }
- op.Inode = fuseops.InodeID(inode)
- }
-
- fullInode, err := sv.LoadFullInode(btrfsprim.ObjID(op.Inode))
- if err != nil {
- return err
- }
-
- size := 0
- for name := range fullInode.XAttrs {
- size += len(name) + 1
- }
- if len(op.Dst) < size {
- return syscall.ERANGE
- }
-
- op.BytesRead = size
- n := 0
- for _, name := range maps.SortedKeys(fullInode.XAttrs) {
- n += copy(op.Dst[n:], name)
- op.Dst[n] = 0
- n++
- }
- return nil
-}
-
-func (sv *subvolume) GetXattr(_ context.Context, op *fuseops.GetXattrOp) error {
- if op.Inode == fuseops.RootInodeID {
- inode, err := sv.GetRootInode()
- if err != nil {
- return err
- }
- op.Inode = fuseops.InodeID(inode)
- }
-
- fullInode, err := sv.LoadFullInode(btrfsprim.ObjID(op.Inode))
- if err != nil {
- return err
- }
-
- val, ok := fullInode.XAttrs[op.Name]
- if !ok {
- return syscall.ENODATA
- }
-
- if len(op.Dst) < len(val) {
- return syscall.ERANGE
- }
-
- op.BytesRead = len(val)
- copy(op.Dst, val)
- return nil
-}
-
-func (sv *subvolume) Destroy() {}
generated by cgit v1.2.3-2-g168b (git 2.25.1) at 2024-10-28 01:54:46 +0000