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- package mount
- import (
- "syscall"
- "github.com/hanwen/go-fuse/v2/fuse"
- "github.com/seaweedfs/seaweedfs/weed/filer"
- "github.com/seaweedfs/seaweedfs/weed/glog"
- )
- // These are non-POSIX extensions
- const (
- SEEK_DATA uint32 = 3 // seek to next data after the offset
- SEEK_HOLE uint32 = 4 // seek to next hole after the offset
- ENXIO = fuse.Status(syscall.ENXIO)
- )
- // Lseek finds next data or hole segments after the specified offset
- // See https://man7.org/linux/man-pages/man2/lseek.2.html
- func (wfs *WFS) Lseek(cancel <-chan struct{}, in *fuse.LseekIn, out *fuse.LseekOut) fuse.Status {
- // not a documented feature
- if in.Padding != 0 {
- return fuse.EINVAL
- }
- if in.Whence != SEEK_DATA && in.Whence != SEEK_HOLE {
- return fuse.EINVAL
- }
- // file must exist
- fh := wfs.GetHandle(FileHandleId(in.Fh))
- if fh == nil {
- return fuse.EBADF
- }
- // lock the file until the proper offset was calculated
- fh.RLock()
- defer fh.RUnlock()
- fh.entryLock.RLock()
- defer fh.entryLock.RUnlock()
- fileSize := int64(filer.FileSize(fh.GetEntry()))
- offset := max(int64(in.Offset), 0)
- glog.V(4).Infof(
- "Lseek %s fh %d in [%d,%d], whence %d",
- fh.FullPath(), fh.fh, offset, fileSize, in.Whence,
- )
- // can neither seek beyond file nor seek to a hole at the end of the file with SEEK_DATA
- if offset > fileSize {
- return ENXIO
- } else if in.Whence == SEEK_DATA && offset == fileSize {
- return ENXIO
- }
- // search chunks for the offset
- found, offset := fh.entryChunkGroup.SearchChunks(offset, fileSize, in.Whence)
- if found {
- out.Offset = uint64(offset)
- return fuse.OK
- }
- // in case we found no exact matches, we return the recommended fallbacks, that is:
- // original offset for SEEK_DATA or end of file for an implicit hole
- if in.Whence == SEEK_DATA {
- out.Offset = in.Offset
- } else {
- out.Offset = uint64(fileSize)
- }
- return fuse.OK
- }
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