Method writeCache

pkg/sentry/fsimpl/gofer/regular_file.go:282–315

(ctx context.Context, d *dentry, offset int64, src usermem.IOSequence)

}

func (fd *regularFileFD) writeCache(ctx context.Context, d *dentry, offset int64, src usermem.IOSequence) error {
	// Write dirty cached pages that will be touched by the write back to
	// the remote file.
	if err := d.writeback(ctx, offset, src.NumBytes()); err != nil {
		return err
	}

	// Remove touched pages from the cache.
	pgstart := hostarch.PageRoundDown(uint64(offset))
	pgend, ok := hostarch.PageRoundUp(uint64(offset + src.NumBytes()))
	if !ok {
		return linuxerr.EINVAL
	}
	mr := memmap.MappableRange{pgstart, pgend}
	var freed []memmap.FileRange

	d.inode.dataMu.Lock()
	d.inode.cache.RemoveRangeWith(mr, func(cseg fsutil.FileRangeIterator) {
		freed = append(freed, memmap.FileRange{cseg.Value(), cseg.Value() + cseg.Range().Length()})
	})
	d.inode.dataMu.Unlock()

	// Invalidate mappings of removed pages.
	d.inode.mapsMu.Lock()
	d.inode.mappings.Invalidate(mr, memmap.InvalidateOpts{})
	d.inode.mapsMu.Unlock()

	// Finally free pages removed from the cache.
	mf := d.inode.fs.mf
	for _, freedFR := range freed {
		mf.DecRef(freedFR)
	}
	return nil
}

// Write implements vfs.FileDescriptionImpl.Write.
func (fd *regularFileFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {