diff options
Diffstat (limited to 'pkg')
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/regular_file.go | 102 |
1 files changed, 56 insertions, 46 deletions
diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go index 420e8efe2..db6bed4f6 100644 --- a/pkg/sentry/fsimpl/gofer/regular_file.go +++ b/pkg/sentry/fsimpl/gofer/regular_file.go @@ -184,6 +184,7 @@ func (fd *regularFileFD) pwrite(ctx context.Context, src usermem.IOSequence, off d.metadataMu.Lock() defer d.metadataMu.Unlock() + // Set offset to file size if the fd was opened with O_APPEND. if fd.vfsfd.StatusFlags()&linux.O_APPEND != 0 { // Holding d.metadataMu is sufficient for reading d.size. @@ -194,70 +195,79 @@ func (fd *regularFileFD) pwrite(ctx context.Context, src usermem.IOSequence, off return 0, offset, err } src = src.TakeFirst64(limit) - n, err := fd.pwriteLocked(ctx, src, offset, opts) - return n, offset + n, err -} -// Preconditions: fd.dentry().metatdataMu must be locked. -func (fd *regularFileFD) pwriteLocked(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { - d := fd.dentry() if d.fs.opts.interop != InteropModeShared { // Compare Linux's mm/filemap.c:__generic_file_write_iter() => // file_update_time(). This is d.touchCMtime(), but without locking // d.metadataMu (recursively). d.touchCMtimeLocked() } - if fd.vfsfd.StatusFlags()&linux.O_DIRECT != 0 { - // 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 0, err - } - // Remove touched pages from the cache. - pgstart := usermem.PageRoundDown(uint64(offset)) - pgend, ok := usermem.PageRoundUp(uint64(offset + src.NumBytes())) - if !ok { - return 0, syserror.EINVAL - } - mr := memmap.MappableRange{pgstart, pgend} - var freed []memmap.FileRange - d.dataMu.Lock() - cseg := d.cache.LowerBoundSegment(mr.Start) - for cseg.Ok() && cseg.Start() < mr.End { - cseg = d.cache.Isolate(cseg, mr) - freed = append(freed, memmap.FileRange{cseg.Value(), cseg.Value() + cseg.Range().Length()}) - cseg = d.cache.Remove(cseg).NextSegment() - } - d.dataMu.Unlock() - // Invalidate mappings of removed pages. - d.mapsMu.Lock() - d.mappings.Invalidate(mr, memmap.InvalidateOpts{}) - d.mapsMu.Unlock() - // Finally free pages removed from the cache. - mf := d.fs.mfp.MemoryFile() - for _, freedFR := range freed { - mf.DecRef(freedFR) - } - } + rw := getDentryReadWriter(ctx, d, offset) + defer putDentryReadWriter(rw) + if fd.vfsfd.StatusFlags()&linux.O_DIRECT != 0 { + if err := fd.writeCache(ctx, d, offset, src); err != nil { + return 0, offset, err + } + // Require the write to go to the remote file. rw.direct = true } + n, err := src.CopyInTo(ctx, rw) - putDentryReadWriter(rw) - if n != 0 && fd.vfsfd.StatusFlags()&(linux.O_DSYNC|linux.O_SYNC) != 0 { - // Write dirty cached pages touched by the write back to the remote - // file. + if err != nil { + return n, offset, err + } + if n > 0 && fd.vfsfd.StatusFlags()&(linux.O_DSYNC|linux.O_SYNC) != 0 { + // Write dirty cached pages touched by the write back to the remote file. if err := d.writeback(ctx, offset, src.NumBytes()); err != nil { - return 0, err + return n, offset, err } // Request the remote filesystem to sync the remote file. - if err := d.handle.file.fsync(ctx); err != nil { - return 0, err + if err := d.handle.sync(ctx); err != nil { + return n, offset, err } } - return n, err + return n, offset + n, nil +} + +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 := usermem.PageRoundDown(uint64(offset)) + pgend, ok := usermem.PageRoundUp(uint64(offset + src.NumBytes())) + if !ok { + return syserror.EINVAL + } + mr := memmap.MappableRange{pgstart, pgend} + var freed []memmap.FileRange + + d.dataMu.Lock() + cseg := d.cache.LowerBoundSegment(mr.Start) + for cseg.Ok() && cseg.Start() < mr.End { + cseg = d.cache.Isolate(cseg, mr) + freed = append(freed, memmap.FileRange{cseg.Value(), cseg.Value() + cseg.Range().Length()}) + cseg = d.cache.Remove(cseg).NextSegment() + } + d.dataMu.Unlock() + + // Invalidate mappings of removed pages. + d.mapsMu.Lock() + d.mappings.Invalidate(mr, memmap.InvalidateOpts{}) + d.mapsMu.Unlock() + + // Finally free pages removed from the cache. + mf := d.fs.mfp.MemoryFile() + for _, freedFR := range freed { + mf.DecRef(freedFR) + } + return nil } // Write implements vfs.FileDescriptionImpl.Write. |