restic/internal/fuse/file.go

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// +build !netbsd
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// +build !openbsd
// +build !solaris
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// +build !windows
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package fuse
import (
"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/restic"
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"github.com/restic/restic/internal/debug"
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"bazil.org/fuse"
"bazil.org/fuse/fs"
"golang.org/x/net/context"
)
// The default block size to report in stat
const blockSize = 512
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// Statically ensure that *file implements the given interface
var _ = fs.HandleReader(&file{})
var _ = fs.HandleReleaser(&file{})
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type file struct {
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root *Root
node *restic.Node
inode uint64
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sizes []int
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blobs [][]byte
}
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func newFile(ctx context.Context, root *Root, inode uint64, node *restic.Node) (fusefile *file, err error) {
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debug.Log("create new file for %v with %d blobs", node.Name, len(node.Content))
var bytes uint64
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sizes := make([]int, len(node.Content))
for i, id := range node.Content {
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size, ok := root.blobSizeCache.Lookup(id)
if !ok {
var found bool
size, found = root.repo.LookupBlobSize(id, restic.DataBlob)
if !found {
return nil, errors.Errorf("id %v not found in repository", id)
}
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}
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sizes[i] = int(size)
bytes += uint64(size)
}
if bytes != node.Size {
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debug.Log("sizes do not match: node.Size %v != size %v, using real size", node.Size, bytes)
node.Size = bytes
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}
return &file{
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inode: inode,
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root: root,
node: node,
sizes: sizes,
blobs: make([][]byte, len(node.Content)),
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}, nil
}
func (f *file) Attr(ctx context.Context, a *fuse.Attr) error {
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debug.Log("Attr(%v)", f.node.Name)
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a.Inode = f.inode
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a.Mode = f.node.Mode
a.Size = f.node.Size
a.Blocks = (f.node.Size / blockSize) + 1
a.BlockSize = blockSize
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a.Nlink = uint32(f.node.Links)
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if !f.root.cfg.OwnerIsRoot {
a.Uid = f.node.UID
a.Gid = f.node.GID
}
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a.Atime = f.node.AccessTime
a.Ctime = f.node.ChangeTime
a.Mtime = f.node.ModTime
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return nil
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}
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func (f *file) getBlobAt(ctx context.Context, i int) (blob []byte, err error) {
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debug.Log("getBlobAt(%v, %v)", f.node.Name, i)
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if f.blobs[i] != nil {
return f.blobs[i], nil
}
// release earlier blobs
for j := 0; j < i; j++ {
f.blobs[j] = nil
}
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buf := restic.NewBlobBuffer(f.sizes[i])
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n, err := f.root.repo.LoadBlob(ctx, restic.DataBlob, f.node.Content[i], buf)
if err != nil {
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debug.Log("LoadBlob(%v, %v) failed: %v", f.node.Name, f.node.Content[i], err)
return nil, err
}
f.blobs[i] = buf[:n]
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return buf[:n], nil
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}
func (f *file) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
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debug.Log("Read(%v, %v, %v), file size %v", f.node.Name, req.Size, req.Offset, f.node.Size)
offset := req.Offset
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if uint64(offset) > f.node.Size {
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debug.Log("Read(%v): offset is greater than file size: %v > %v",
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f.node.Name, req.Offset, f.node.Size)
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// return no data
resp.Data = resp.Data[:0]
return nil
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}
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// handle special case: file is empty
if f.node.Size == 0 {
resp.Data = resp.Data[:0]
return nil
}
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// Skip blobs before the offset
startContent := 0
for offset > int64(f.sizes[startContent]) {
offset -= int64(f.sizes[startContent])
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startContent++
}
dst := resp.Data[0:req.Size]
readBytes := 0
remainingBytes := req.Size
for i := startContent; remainingBytes > 0 && i < len(f.sizes); i++ {
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blob, err := f.getBlobAt(ctx, i)
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if err != nil {
return err
}
if offset > 0 {
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blob = blob[offset:]
offset = 0
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}
copied := copy(dst, blob)
remainingBytes -= copied
readBytes += copied
dst = dst[copied:]
}
resp.Data = resp.Data[:readBytes]
return nil
}
func (f *file) Release(ctx context.Context, req *fuse.ReleaseRequest) error {
for i := range f.blobs {
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f.blobs[i] = nil
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}
return nil
}
func (f *file) Listxattr(ctx context.Context, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error {
debug.Log("Listxattr(%v, %v)", f.node.Name, req.Size)
for _, attr := range f.node.ExtendedAttributes {
resp.Append(attr.Name)
}
return nil
}
func (f *file) Getxattr(ctx context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error {
debug.Log("Getxattr(%v, %v, %v)", f.node.Name, req.Name, req.Size)
attrval := f.node.GetExtendedAttribute(req.Name)
if attrval != nil {
resp.Xattr = attrval
return nil
}
return fuse.ErrNoXattr
}