gsh-digital-services/seaweedFS
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read randomly written data

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This commit is contained in:
Chris Lu
2020-08-16 15:16:46 -07:00
parent 20e0bae5d1
commit 2ba817afac
3 changed files with 122 additions and 71 deletions
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59
weed/filer2/reader_at.go
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@@ -16,7 +16,7 @@ type ChunkReadAt struct {
masterClient *wdclient.MasterClient
chunkViews []*ChunkView
buffer []byte
bufferOffset int64
bufferFileId string
lookupFileId func(fileId string) (targetUrl string, err error)
readerLock sync.Mutex
fileSize int64
@@ -60,7 +60,6 @@ func NewChunkReaderAtFromClient(filerClient filer_pb.FilerClient, chunkViews []*
return &ChunkReadAt{
chunkViews: chunkViews,
lookupFileId: LookupFn(filerClient),
bufferOffset: -1,
chunkCache: chunkCache,
fileSize: fileSize,
}
@@ -83,71 +82,71 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
var found bool
var chunkStart, chunkStop int64
var chunkView *ChunkView
for _, chunk := range c.chunkViews {
// fmt.Printf(">>> doReadAt [%d,%d), chunk[%d,%d), %v && %v\n", offset, offset+int64(len(p)), chunk.LogicOffset, chunk.LogicOffset+int64(chunk.Size), chunk.LogicOffset <= offset, offset < chunk.LogicOffset+int64(chunk.Size))
// fmt.Printf(">>> doReadAt [%d,%d), chunk[%d,%d)\n", offset, offset+int64(len(p)), chunk.LogicOffset, chunk.LogicOffset+int64(chunk.Size))
chunkStart, chunkStop = max(chunk.LogicOffset, offset), min(chunk.LogicOffset+int64(chunk.Size), offset+int64(len(p)))
chunkView = chunk
if chunkStart < chunkStop {
// fmt.Printf(">>> found [%d,%d), chunk %s [%d,%d)\n", chunkStart, chunkStop, chunk.FileId, chunk.LogicOffset, chunk.LogicOffset+int64(chunk.Size))
found = true
if c.bufferOffset != chunk.LogicOffset {
c.buffer, err = c.fetchChunkData(chunk)
if err != nil {
glog.Errorf("fetching chunk %+v: %v\n", chunk, err)
}
c.bufferOffset = chunk.LogicOffset
c.buffer, err = c.fetchWholeChunkData(chunk)
if err != nil {
glog.Errorf("fetching chunk %+v: %v\n", chunk, err)
}
c.bufferFileId = chunk.FileId
break
}
}
// fmt.Printf("> doReadAt [%d,%d), buffer:[%d,%d), found:%v, err:%v\n", offset, offset+int64(len(p)), c.bufferOffset, c.bufferOffset+int64(len(c.buffer)), found, err)
// fmt.Printf("> doReadAt [%d,%d), buffer %s:%d, found:%v, err:%v\n", offset, offset+int64(len(p)), c.bufferFileId, int64(len(c.buffer)), found, err)
if err != nil {
return
}
if found {
n = int(chunkStart-offset) + copy(p[chunkStart-offset:chunkStop-offset], c.buffer[chunkStart-c.bufferOffset:chunkStop-c.bufferOffset])
bufferOffset := chunkStart - chunkView.LogicOffset + chunkView.Offset
/*
skipped, copied := chunkStart-offset, chunkStop-chunkStart
fmt.Printf("+++ copy %d+%d=%d fill:[%d, %d) p[%d,%d) <- buffer:[%d,%d) buffer %s:%d\nchunkView:%+v\n\n",
skipped, copied, skipped+copied,
chunkStart, chunkStop,
chunkStart-offset, chunkStop-offset, bufferOffset, bufferOffset+chunkStop-chunkStart,
c.bufferFileId, len(c.buffer),
chunkView)
*/
n = int(chunkStart-offset) +
copy(p[chunkStart-offset:chunkStop-offset], c.buffer[bufferOffset:bufferOffset+chunkStop-chunkStart])
return
}
n = len(p)
if offset+int64(n) >= c.fileSize {
err = io.EOF
n = int(c.fileSize - offset)
}
// fmt.Printf("~~~ filled %d, err: %v\n\n", n, err)
return
}
func (c *ChunkReadAt) fetchChunkData(chunkView *ChunkView) (data []byte, err error) {
func (c *ChunkReadAt) fetchWholeChunkData(chunkView *ChunkView) (chunkData []byte, err error) {
glog.V(5).Infof("fetchChunkData %s [%d,%d)\n", chunkView.FileId, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size))
glog.V(4).Infof("fetchWholeChunkData %s offset %d [%d,%d)\n", chunkView.FileId, chunkView.Offset, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size))
hasDataInCache := false
chunkData := c.chunkCache.GetChunk(chunkView.FileId, chunkView.ChunkSize)
chunkData = c.chunkCache.GetChunk(chunkView.FileId, chunkView.ChunkSize)
if chunkData != nil {
glog.V(5).Infof("cache hit %s [%d,%d)", chunkView.FileId, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size))
hasDataInCache = true
glog.V(5).Infof("cache hit %s [%d,%d)", chunkView.FileId, chunkView.LogicOffset-chunkView.Offset, chunkView.LogicOffset-chunkView.Offset + int64(len(chunkData)))
} else {
chunkData, err = c.doFetchFullChunkData(chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped)
if err != nil {
return nil, err
return
}
}
if int64(len(chunkData)) < chunkView.Offset+int64(chunkView.Size) {
glog.Errorf("unexpected larger cached:%v chunk %s [%d,%d) than %d", hasDataInCache, chunkView.FileId, chunkView.Offset, chunkView.Offset+int64(chunkView.Size), len(chunkData))
return nil, fmt.Errorf("unexpected larger cached:%v chunk %s [%d,%d) than %d", hasDataInCache, chunkView.FileId, chunkView.Offset, chunkView.Offset+int64(chunkView.Size), len(chunkData))
}
data = chunkData[chunkView.Offset : chunkView.Offset+int64(chunkView.Size)]
if !hasDataInCache {
c.chunkCache.SetChunk(chunkView.FileId, chunkData)
}
return data, nil
return
}
func (c *ChunkReadAt) doFetchFullChunkData(fileId string, cipherKey []byte, isGzipped bool) ([]byte, error) {