"Prefer patch uploads" option

internal/cfg/config.go

@@ -103,6 +103,7 @@ type FlagStorage struct {
 	PartSizes             []PartSizeConfig
 	UsePatch              bool
 	DropPatchConflicts    bool
+	PreferPatchUploads    bool
 
 	// Debugging
 	DebugMain  bool

internal/cfg/flags.go

@@ -433,14 +433,21 @@ MISC OPTIONS:
 
 		cli.BoolFlag{
 			Name:  "enable-patch",
-			Usage: "Use PATCH method to upload object data changes to s3. Yandex only. (default: off)",
+			Usage: "Use PATCH method to upload object data changes to S3. All PATCH related flags are Yandex only. (default: off)",
 		},
 
 		cli.BoolFlag{
 			Name:  "drop-patch-conflicts",
 			Usage: "Drop local changes in case of conflicting concurrent PATCH updates. (default: off)",
 		},
 
+		cli.BoolFlag{
+			Name: "prefer-patch-uploads",
+			Usage: "When uploading new objects, prefer PATCH requests to standard multipart upload process." +
+				"This allows for changes to appear faster in exchange for slower upload speed due to limited parallelism." +
+				"Must be used with --enable-patch flag (default: off)",
+		},
+
 		cli.IntFlag{
 			Name:  "max-merge-copy",
 			Value: 0,
@@ -860,6 +867,7 @@ func PopulateFlags(c *cli.Context) (ret *FlagStorage) {
 		CacheFileMode:          os.FileMode(c.Int("cache-file-mode")),
 		UsePatch:               c.Bool("enable-patch"),
 		DropPatchConflicts:     c.Bool("drop-patch-conflicts"),
+		PreferPatchUploads:     c.Bool("prefer-patch-uploads"),
 
 		// Common Backend Config
 		Endpoint:               c.String("endpoint"),

internal/file.go

@@ -716,7 +716,11 @@ func (inode *Inode) sendUpload(priority int) bool {
 		if inode.IsFlushing > 0 {
 			return false
 		}
-		inode.sendStartMultipart()
+		if inode.fs.flags.UsePatch && inode.fs.flags.PreferPatchUploads {
+			inode.uploadMinMultipart()
+		} else {
+			inode.sendStartMultipart()
+		}
 		return true
 	}
 
@@ -954,6 +958,15 @@ func (inode *Inode) sendStartMultipart() {
 	atomic.AddInt64(&inode.fs.stats.flushes, 1)
 	atomic.AddInt64(&inode.fs.activeFlushers, 1)
 	go func() {
+		inode.beginMultipartUpload(cloud, key)
+		inode.IsFlushing -= inode.fs.flags.MaxParallelParts
+		atomic.AddInt64(&inode.fs.activeFlushers, -1)
+		inode.fs.WakeupFlusher()
+		inode.mu.Unlock()
+	}()
+}
+
+func (inode *Inode) beginMultipartUpload(cloud StorageBackend, key string) {
 		params := &MultipartBlobBeginInput{
 			Key: key,
 			ContentType: inode.fs.flags.GetMimeType(key),
@@ -973,11 +986,6 @@ func (inode *Inode) sendStartMultipart() {
 			log.Debugf("Started multi-part upload of object %v", key)
 			inode.mpu = resp
 		}
-		inode.IsFlushing -= inode.fs.flags.MaxParallelParts
-		atomic.AddInt64(&inode.fs.activeFlushers, -1)
-		inode.fs.WakeupFlusher()
-		inode.mu.Unlock()
-	}()
 }
 
 func (inode *Inode) sendUploadParts(priority int) (bool, bool) {
@@ -1090,6 +1098,61 @@ func (inode *Inode) uploadedAsMultipart() bool {
 	return strings.Contains(inode.knownETag, "-")
 }
 
+func (inode *Inode) uploadMinMultipart() {
+	inode.IsFlushing += inode.fs.flags.MaxParallelParts
+	atomic.AddInt64(&inode.fs.activeFlushers, 1)
+
+	cloud, key := inode.cloud()
+	if inode.isDir() {
+		key += "/"
+	}
+
+	go func() {
+		defer func() {
+			inode.IsFlushing -= inode.fs.flags.MaxParallelParts
+			atomic.AddInt64(&inode.fs.activeFlushers, -1)
+			inode.fs.WakeupFlusher()
+			inode.mu.Unlock()
+		}()
+
+		atomic.AddInt64(&inode.fs.stats.flushes, 1)
+		inode.beginMultipartUpload(cloud, key)
+		if inode.mpu == nil {
+			return
+		}
+
+		if ok := inode.syncFlushPartsUpTo(2); !ok {
+			inode.abortMultipart()
+			return
+		}
+
+		partOffset, partSize := inode.fs.partRange(1)
+		if inode.Attributes.Size < partOffset+partSize {
+			partSize = inode.Attributes.Size - partOffset
+		}
+
+		atomic.AddInt64(&inode.fs.stats.flushes, 1)
+		inode.commitMultipartUpload(2, partOffset+partSize)
+		if inode.mpu != nil {
+			inode.abortMultipart()
+		}
+	}()
+}
+
+func (inode *Inode) syncFlushPartsUpTo(part uint64) bool {
+	if inode.mpu == nil {
+		return false
+	}
+	for i := uint64(0); i < part; i++ {
+		atomic.AddInt64(&inode.fs.stats.flushes, 1)
+		inode.flushPart(i)
+		if inode.mpu == nil || inode.mpu.Parts[i] == nil {
+			return false
+		}
+	}
+	return true
+}
+
 func (inode *Inode) patchObjectRanges() (initiated bool) {
 	smallFile := inode.Attributes.Size <= inode.fs.flags.SinglePartMB*1024*1024
 	wantFlush := inode.fileHandles == 0 || inode.forceFlush || atomic.LoadInt32(&inode.fs.wantFree) > 0
@@ -1116,7 +1179,11 @@ func (inode *Inode) patchObjectRanges() (initiated bool) {
 			return false
 		}
 
-		_, prevSize := inode.fs.partRange(MaxUInt64(part-1, 0))
+		var prevPart uint64
+		if part > 0 {
+			prevPart = part - 1
+		}
+		_, prevSize := inode.fs.partRange(prevPart)
 
 		partEnd, rangeBorder := partStart+partSize, partSize != prevSize
 		appendPatch, newPart := partEnd > inode.knownSize, partStart == inode.knownSize
@@ -1345,6 +1412,15 @@ func (inode *Inode) resetCache() {
 	}
 	// And abort multipart upload, too
 	if inode.mpu != nil {
+		inode.abortMultipart()
+	}
+	inode.userMetadataDirty = 0
+	inode.SetCacheState(ST_CACHED)
+	// Invalidate metadata entry
+	inode.SetAttrTime(time.Time{})
+}
+
+func (inode *Inode) abortMultipart() {
 		cloud, key := inode.cloud()
 		go func(mpu *MultipartBlobCommitInput) {
 			_, abortErr := cloud.MultipartBlobAbort(mpu)
@@ -1354,11 +1430,6 @@ func (inode *Inode) resetCache() {
 		}(inode.mpu)
 		inode.mpu = nil
 	}
-	inode.userMetadataDirty = 0
-	inode.SetCacheState(ST_CACHED)
-	// Invalidate metadata entry
-	inode.SetAttrTime(time.Time{})
-}
 
 func (inode *Inode) flushSmallObject() {
 
@@ -1422,13 +1493,7 @@ func (inode *Inode) flushSmallObject() {
 	if inode.mpu != nil {
 		// Abort and forget abort multipart upload, because otherwise we may
 		// not be able to proceed to rename - it waits until inode.mpu == nil
-		go func(mpu *MultipartBlobCommitInput) {
-			_, abortErr := cloud.MultipartBlobAbort(mpu)
-			if abortErr != nil {
-				log.Warnf("Failed to abort multi-part upload of object %v: %v", key, abortErr)
-			}
-		}(inode.mpu)
-		inode.mpu = nil
+		inode.abortMultipart()
 	}
 	inode.mu.Unlock()
 	inode.fs.addInflightChange(key)
@@ -1677,6 +1742,10 @@ func (inode *Inode) completeMultipart() {
 		// Error, or already flushed, or conflict => do not complete
 		return
 	}
+	inode.commitMultipartUpload(numParts, finalSize)
+}
+
+func (inode *Inode) commitMultipartUpload(numParts, finalSize uint64) {
 	cloud, key := inode.cloud()
 	if inode.oldParent != nil {
 		// Always apply modifications before moving