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count 0 as part of the reads

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This commit is contained in:
Chris Lu 2020-08-17 20:14:40 -07:00
parent 0be4b6e7f0
commit 0625e63648
1 changed files with 24 additions and 25 deletions
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49
weed/filer2/reader_at.go
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@ -15,8 +15,6 @@ import (
type ChunkReadAt struct {
masterClient *wdclient.MasterClient
chunkViews []*ChunkView
buffer []byte
bufferFileId string
lookupFileId func(fileId string) (targetUrl string, err error)
readerLock sync.Mutex
fileSize int64
@ -71,49 +69,50 @@ func (c *ChunkReadAt) ReadAt(p []byte, offset int64) (n int, err error) {
defer c.readerLock.Unlock()
glog.V(4).Infof("ReadAt [%d,%d) of total file size %d bytes %d chunk views", offset, offset+int64(len(p)), c.fileSize, len(c.chunkViews))
for n < len(p) && err == nil {
readCount, readErr := c.doReadAt(p[n:], offset+int64(n))
n += readCount
err = readErr
}
return
return c.doReadAt(p[n:], offset+int64(n))
}
func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
var startOffset = offset
var buffer []byte
startOffset, remaining := offset, int64(len(p))
for i, chunk := range c.chunkViews {
if startOffset < min(chunk.LogicOffset, int64(len(p))+offset) {
gap := int(min(chunk.LogicOffset, int64(len(p))+offset) - startOffset)
if remaining <= 0 {
break
}
if startOffset < chunk.LogicOffset {
gap := int(chunk.LogicOffset - startOffset)
glog.V(4).Infof("zero [%d,%d)", n, n+gap)
n += gap
startOffset = chunk.LogicOffset
startOffset, remaining = chunk.LogicOffset, remaining-int64(gap)
if remaining <= 0 {
break
}
}
// 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)))
chunkStart, chunkStop := max(chunk.LogicOffset, startOffset), min(chunk.LogicOffset+int64(chunk.Size), startOffset+remaining)
if chunkStart >= chunkStop {
continue
}
glog.V(4).Infof("read [%d,%d), %d chunk %s [%d,%d)", chunkStart, chunkStop, i, chunk.FileId, chunk.LogicOffset-chunk.Offset, chunk.LogicOffset-chunk.Offset+int64(chunk.Size))
c.buffer, err = c.fetchWholeChunkData(chunk)
glog.V(4).Infof("read [%d,%d), %d/%d chunk %s [%d,%d)", chunkStart, chunkStop, i, len(c.chunkViews), chunk.FileId, chunk.LogicOffset-chunk.Offset, chunk.LogicOffset-chunk.Offset+int64(chunk.Size))
buffer, err = c.readFromWholeChunkData(chunk)
if err != nil {
glog.Errorf("fetching chunk %+v: %v\n", chunk, err)
return
}
c.bufferFileId = chunk.FileId
bufferOffset := chunkStart - chunk.LogicOffset + chunk.Offset
copied := copy(p[chunkStart-offset:chunkStop-offset], c.buffer[bufferOffset:bufferOffset+chunkStop-chunkStart])
copied := copy(p[chunkStart-startOffset:chunkStop-startOffset], buffer[bufferOffset:bufferOffset+chunkStop-chunkStart])
n += copied
startOffset += int64(copied)
startOffset, remaining = startOffset + int64(copied), remaining-int64(copied)
}
// 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)
glog.V(4).Infof("doReadAt [%d,%d), n:%v, err:%v", offset, offset+int64(len(p)), n, err)
if startOffset < min(c.fileSize, int64(len(p))+offset) {
gap := int(min(c.fileSize, int64(len(p))+offset) - startOffset)
glog.V(4).Infof("zero2 [%d,%d)", n, n+gap)
n += gap
if remaining > 0 {
glog.V(4).Infof("zero2 [%d,%d)", n, n+int(remaining))
n += int(remaining)
}
if offset+int64(n) >= c.fileSize {
err = io.EOF
}
@ -123,9 +122,9 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
}
func (c *ChunkReadAt) fetchWholeChunkData(chunkView *ChunkView) (chunkData []byte, err error) {
func (c *ChunkReadAt) readFromWholeChunkData(chunkView *ChunkView) (chunkData []byte, err error) {
glog.V(4).Infof("fetchWholeChunkData %s offset %d [%d,%d) size at least %d", chunkView.FileId, chunkView.Offset, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size), chunkView.ChunkSize)
glog.V(4).Infof("readFromWholeChunkData %s offset %d [%d,%d) size at least %d", chunkView.FileId, chunkView.Offset, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size), chunkView.ChunkSize)
chunkData = c.chunkCache.GetChunk(chunkView.FileId, chunkView.ChunkSize)
if chunkData != nil {