diff options
| -rw-r--r-- | internal/fusefrontend/file_allocate_truncate.go | 68 | ||||
| -rw-r--r-- | internal/fusefrontend/file_holes.go | 9 |
2 files changed, 45 insertions, 32 deletions
diff --git a/internal/fusefrontend/file_allocate_truncate.go b/internal/fusefrontend/file_allocate_truncate.go index 6f27ac7..0e12981 100644 --- a/internal/fusefrontend/file_allocate_truncate.go +++ b/internal/fusefrontend/file_allocate_truncate.go @@ -183,35 +183,47 @@ func (f *file) truncateGrowFile(oldPlainSz uint64, newPlainSz uint64) fuse.Statu if newPlainSz <= oldPlainSz { log.Panicf("BUG: newSize=%d <= oldSize=%d", newPlainSz, oldPlainSz) } - var err error - // File was empty, create new header - if oldPlainSz == 0 { - f.fileTableEntry.IDLock.Lock() - _, err = f.createHeader() - f.fileTableEntry.IDLock.Unlock() - if err != nil { - return fuse.ToStatus(err) - } - } - // New blocks to add - addBlocks := f.contentEnc.ExplodePlainRange(oldPlainSz, newPlainSz-oldPlainSz) - if oldPlainSz > 0 && len(addBlocks) >= 2 { - // Zero-pad the first block (unless the first block is also the last block) - f.zeroPad(oldPlainSz) - } - lastBlock := addBlocks[len(addBlocks)-1] - if lastBlock.IsPartial() { - // Write at the new end of the file. The seek implicitly grows the file - // (creates a file hole) and doWrite() takes care of RMW. - off := lastBlock.BlockPlainOff() - _, status := f.doWrite(make([]byte, lastBlock.Length), int64(off+lastBlock.Skip)) + var n1 uint64 + if oldPlainSz > 0 { + n1 = f.contentEnc.PlainOffToBlockNo(oldPlainSz - 1) + } + newEofOffset := newPlainSz - 1 + n2 := f.contentEnc.PlainOffToBlockNo(newEofOffset) + // The file is grown within one block, no need to pad anything. + // Write a single zero to the last byte and let doWrite figure out the RMW. + if n1 == n2 { + buf := make([]byte, 1) + _, status := f.doWrite(buf, int64(newEofOffset)) return status } - - off := lastBlock.BlockCipherOff() - err = syscall.Ftruncate(f.intFd(), int64(off+f.contentEnc.CipherBS())) - if err != nil { - tlog.Warn.Printf("Truncate: grow Ftruncate returned error: %v", err) + // The truncate creates at least one new block. + // + // Make sure the old last block is padded to the block boundary. This call + // is a no-op if it is already block-aligned. + f.zeroPad(oldPlainSz) + // The new size is block-aligned. In this case we can do everything ourselves + // and avoid the call to doWrite. + if newPlainSz%f.contentEnc.PlainBS() == 0 { + // The file was empty, so it did not have a header. Create one. + if oldPlainSz == 0 { + f.fileTableEntry.IDLock.Lock() + defer f.fileTableEntry.IDLock.Unlock() + id, err := f.createHeader() + if err != nil { + return fuse.ToStatus(err) + } + f.fileTableEntry.ID = id + } + cSz := int64(f.contentEnc.PlainSizeToCipherSize(newPlainSz)) + err := syscall.Ftruncate(f.intFd(), cSz) + if err != nil { + tlog.Warn.Printf("Truncate: grow Ftruncate returned error: %v", err) + } + return fuse.ToStatus(err) } - return fuse.ToStatus(err) + // The new size is NOT aligned, so we need to write a partial block. + // Write a single zero to the last byte and let doWrite figure it out. + buf := make([]byte, 1) + _, status := f.doWrite(buf, int64(newEofOffset)) + return status } diff --git a/internal/fusefrontend/file_holes.go b/internal/fusefrontend/file_holes.go index 5b7a244..d779191 100644 --- a/internal/fusefrontend/file_holes.go +++ b/internal/fusefrontend/file_holes.go @@ -30,7 +30,7 @@ func (f *file) writePadHole(targetOff int64) fuse.Status { } // The write goes past the next block. nextBlock has // to be zero-padded to the block boundary and (at least) nextBlock+1 - // will become a file hole in the ciphertext. + // will contain a file hole in the ciphertext. status := f.zeroPad(plainSize) if status != fuse.OK { tlog.Warn.Printf("zeroPad returned error %v", status) @@ -39,14 +39,15 @@ func (f *file) writePadHole(targetOff int64) fuse.Status { return fuse.OK } -// Zero-pad the file of size plainSize to the next block boundary +// Zero-pad the file of size plainSize to the next block boundary. This is a no-op +// if the file is already block-aligned. func (f *file) zeroPad(plainSize uint64) fuse.Status { lastBlockLen := plainSize % f.contentEnc.PlainBS() - missing := f.contentEnc.PlainBS() - lastBlockLen - if missing == 0 { + if lastBlockLen == 0 { // Already block-aligned return fuse.OK } + missing := f.contentEnc.PlainBS() - lastBlockLen pad := make([]byte, missing) tlog.Debug.Printf("zeroPad: Writing %d bytes\n", missing) _, status := f.doWrite(pad, int64(plainSize)) |