seaweedfs/weed/mount/weedfs_file_copy_range.go

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package mount
import (
"io"
"net/http"
"github.com/hanwen/go-fuse/v2/fuse"
"github.com/seaweedfs/seaweedfs/weed/glog"
)
// CopyFileRange copies data from one file to another from and to specified offsets.
//
// See https://man7.org/linux/man-pages/man2/copy_file_range.2.html
// See https://github.com/libfuse/libfuse/commit/fe4f9428fc403fa8b99051f52d84ea5bd13f3855
/**
* Copy a range of data from one file to another
*
* Niels de Vos: libfuse: add copy_file_range() support
*
* Performs an optimized copy between two file descriptors without the
* additional cost of transferring data through the FUSE kernel module
* to user space (glibc) and then back into the FUSE filesystem again.
*
* In case this method is not implemented, applications are expected to
* fall back to a regular file copy. (Some glibc versions did this
* emulation automatically, but the emulation has been removed from all
* glibc release branches.)
*/
func (wfs *WFS) CopyFileRange(cancel <-chan struct{}, in *fuse.CopyFileRangeIn) (written uint32, code fuse.Status) {
// flags must equal 0 for this syscall as of now
if in.Flags != 0 {
return 0, fuse.EINVAL
}
// files must exist
fhOut := wfs.GetHandle(FileHandleId(in.FhOut))
if fhOut == nil {
return 0, fuse.EBADF
}
fhIn := wfs.GetHandle(FileHandleId(in.FhIn))
if fhIn == nil {
return 0, fuse.EBADF
}
// lock source and target file handles
fhOut.Lock()
defer fhOut.Unlock()
fhOut.entryLock.Lock()
defer fhOut.entryLock.Unlock()
if fhOut.entry == nil {
return 0, fuse.ENOENT
}
if fhIn.fh != fhOut.fh {
fhIn.Lock()
defer fhIn.Unlock()
fhIn.entryLock.Lock()
defer fhIn.entryLock.Unlock()
}
// directories are not supported
if fhIn.entry.IsDirectory || fhOut.entry.IsDirectory {
return 0, fuse.EISDIR
}
glog.V(4).Infof(
"CopyFileRange %s fhIn %d -> %s fhOut %d, [%d,%d) -> [%d,%d)",
fhIn.FullPath(), fhIn.fh,
fhOut.FullPath(), fhOut.fh,
in.OffIn, in.OffIn+in.Len,
in.OffOut, in.OffOut+in.Len,
)
data, totalRead, err := readDataByFileHandle(fhIn, in)
if err != nil {
glog.Warningf("file handle read %s %d: %v", fhIn.FullPath(), totalRead, err)
return 0, fuse.EIO
}
if totalRead == 0 {
return 0, fuse.OK
}
// put data at the specified offset in target file
fhOut.dirtyPages.writerPattern.MonitorWriteAt(int64(in.OffOut), int(in.Len))
fhOut.entry.Content = nil
fhOut.dirtyPages.AddPage(int64(in.OffOut), data[:totalRead], fhOut.dirtyPages.writerPattern.IsSequentialMode())
fhOut.entry.Attributes.FileSize = uint64(max(int64(in.OffOut)+totalRead, int64(fhOut.entry.Attributes.FileSize)))
fhOut.dirtyMetadata = true
written = uint32(totalRead)
// detect mime type
if written > 0 && in.OffOut <= 512 {
fhOut.contentType = http.DetectContentType(data[:min(totalRead, 512)-1])
}
return written, fuse.OK
}
func readDataByFileHandle(fhIn *FileHandle, in *fuse.CopyFileRangeIn) ([]byte, int64, error) {
// read data from source file
fhIn.lockForRead(int64(in.OffIn), int(in.Len))
defer fhIn.unlockForRead(int64(in.OffIn), int(in.Len))
data := make([]byte, int(in.Len))
totalRead, err := fhIn.readFromChunks(data, int64(in.OffIn))
if err == nil || err == io.EOF {
maxStop := fhIn.readFromDirtyPages(data, int64(in.OffIn))
totalRead = max(maxStop-int64(in.OffIn), totalRead)
}
if err == io.EOF {
err = nil
}
return data, totalRead, err
}