diff options
Diffstat (limited to 'internal')
| -rw-r--r-- | internal/contentenc/offsets.go | 1 | ||||
| -rw-r--r-- | internal/fusefrontend/file.go | 48 | ||||
| -rw-r--r-- | internal/fusefrontend/file_holes.go | 4 |
3 files changed, 25 insertions, 28 deletions
diff --git a/internal/contentenc/offsets.go b/internal/contentenc/offsets.go index da0551a..256ea26 100644 --- a/internal/contentenc/offsets.go +++ b/internal/contentenc/offsets.go @@ -66,6 +66,7 @@ func (be *ContentEnc) PlainSizeToCipherSize(plainSize uint64) uint64 { } // Split a plaintext byte range into (possibly partial) blocks +// Returns an empty slice if length == 0. func (be *ContentEnc) ExplodePlainRange(offset uint64, length uint64) []intraBlock { var blocks []intraBlock var nextBlock intraBlock diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go index 513dbbf..8f13553 100644 --- a/internal/fusefrontend/file.go +++ b/internal/fusefrontend/file.go @@ -217,6 +217,8 @@ const FALLOC_FL_KEEP_SIZE = 0x01 // // Called by Write() for normal writing, // and by Truncate() to rewrite the last file block. +// +// Empty writes do nothing and are allowed. func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) { // Read header from disk, create a new one if the file is empty @@ -282,6 +284,8 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) { } // Write - FUSE call +// +// If the write creates a hole, pads the file to the next block boundary. func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) { f.fdLock.RLock() defer f.fdLock.RUnlock() @@ -362,7 +366,6 @@ func (f *file) Truncate(newSize uint64) fuse.Status { wlock.lock(f.ino) defer wlock.unlock(f.ino) var err error - // Common case first: Truncate to zero if newSize == 0 { err = syscall.Ftruncate(int(f.fd.Fd()), 0) @@ -374,7 +377,6 @@ func (f *file) Truncate(newSize uint64) fuse.Status { f.header = nil return fuse.OK } - // We need the old file size to determine if we are growing or shrinking // the file fi, err := f.fd.Stat() @@ -388,12 +390,10 @@ func (f *file) Truncate(newSize uint64) fuse.Status { newB := float32(newSize) / float32(f.contentEnc.PlainBS()) tlog.Debug.Printf("ino%d: FUSE Truncate from %.2f to %.2f blocks (%d to %d bytes)", f.ino, oldB, newB, oldSize, newSize) } - // File size stays the same - nothing to do if newSize == oldSize { return fuse.OK } - // File grows if newSize > oldSize { // File was empty, create new header @@ -405,30 +405,22 @@ func (f *file) Truncate(newSize uint64) fuse.Status { } // New blocks to add addBlocks := f.contentEnc.ExplodePlainRange(oldSize, newSize-oldSize) - for _, b := range addBlocks { - // First and last block may be partial and must be actually written - if b.IsPartial() { - off, _ := b.PlaintextRange() - off += b.Skip - _, status := f.doWrite(make([]byte, b.Length), int64(off)) - if status != fuse.OK { - return status - } - } else { - // Complete all-zero blocks can stay all-zero because we do file - // hole passthrough. - // TODO We are growing the file block-by-block which is pretty - // inefficient. We could coalesce all the grows into a single - // Ftruncate. - off, length := b.CiphertextRange() - err = syscall.Ftruncate(int(f.fd.Fd()), int64(off+length)) - if err != nil { - tlog.Warn.Printf("grow Ftruncate returned error: %v", err) - return fuse.ToStatus(err) - } + if len(addBlocks) >= 2 { + f.zeroPad(oldSize) + } + lastBlock := addBlocks[len(addBlocks)-1] + if lastBlock.IsPartial() { + off, _ := lastBlock.PlaintextRange() + _, status := f.doWrite(make([]byte, lastBlock.Length), int64(off+lastBlock.Skip)) + return status + } else { + off, length := lastBlock.CiphertextRange() + err = syscall.Ftruncate(f.intFd(), int64(off+length)) + if err != nil { + tlog.Warn.Printf("Truncate: grow Ftruncate returned error: %v", err) } + return fuse.ToStatus(err) } - return fuse.OK } else { // File shrinks blockNo := f.contentEnc.PlainOffToBlockNo(newSize) @@ -440,14 +432,14 @@ func (f *file) Truncate(newSize uint64) fuse.Status { var status fuse.Status data, status = f.doRead(plainOff, lastBlockLen) if status != fuse.OK { - tlog.Warn.Printf("shrink doRead returned error: %v", err) + tlog.Warn.Printf("Truncate: shrink doRead returned error: %v", err) return status } } // Truncate down to the last complete block err = syscall.Ftruncate(int(f.fd.Fd()), int64(cipherOff)) if err != nil { - tlog.Warn.Printf("shrink Ftruncate returned error: %v", err) + tlog.Warn.Printf("Truncate: shrink Ftruncate returned error: %v", err) return fuse.ToStatus(err) } // Append partial block diff --git a/internal/fusefrontend/file_holes.go b/internal/fusefrontend/file_holes.go index 46a5865..1d9a5fb 100644 --- a/internal/fusefrontend/file_holes.go +++ b/internal/fusefrontend/file_holes.go @@ -22,6 +22,10 @@ func (f *file) createsHole(plainSize uint64, off int64) bool { func (f *file) zeroPad(plainSize uint64) fuse.Status { lastBlockLen := plainSize % f.contentEnc.PlainBS() missing := f.contentEnc.PlainBS() - lastBlockLen + if missing == 0 { + // Already block-aligned + return fuse.OK + } pad := make([]byte, missing) tlog.Debug.Printf("zeroPad: Writing %d bytes\n", missing) _, status := f.doWrite(pad, int64(plainSize)) |