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Merge pull request #2037 from utsl42/reader_at

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make reader_at handle random reads more efficiently for FUSE
This commit is contained in:
Chris Lu
2021-04-28 17:31:46 -07:00
committed by GitHub
parent a26a37dfa3 042de9359c
commit fa0d973113
6 changed files with 152 additions and 7 deletions
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22
weed/filer/reader_at.go
View File

@@ -139,13 +139,15 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
}
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))
var buffer []byte
buffer, err = c.readFromWholeChunkData(chunk, nextChunk)
bufferOffset := chunkStart - chunk.LogicOffset + chunk.Offset
bufferLength := chunkStop - chunkStart
buffer, err = c.readChunkSlice(chunk, nextChunk, uint64(bufferOffset), uint64(bufferLength))
if err != nil {
glog.Errorf("fetching chunk %+v: %v\n", chunk, err)
return
}
bufferOffset := chunkStart - chunk.LogicOffset + chunk.Offset
copied := copy(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], buffer[bufferOffset:bufferOffset+chunkStop-chunkStart])
copied := copy(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], buffer)
n += copied
startOffset, remaining = startOffset+int64(copied), remaining-int64(copied)
}
@@ -167,6 +169,20 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
}
func (c *ChunkReadAt) readChunkSlice(chunkView *ChunkView, nextChunkViews *ChunkView, offset, length uint64) ([]byte, error) {
chunkSlice := c.chunkCache.GetChunkSlice(chunkView.FileId, offset, length)
if len(chunkSlice) > 0 {
return chunkSlice, nil
}
chunkData, err := c.readFromWholeChunkData(chunkView, nextChunkViews)
if err != nil {
return nil, err
}
wanted := min(int64(length), int64(len(chunkData))-int64(offset))
return chunkData[offset : int64(offset)+wanted], nil
}
func (c *ChunkReadAt) readFromWholeChunkData(chunkView *ChunkView, nextChunkViews ...*ChunkView) (chunkData []byte, err error) {
if c.lastChunkFileId == chunkView.FileId {

5
weed/filer/reader_at_test.go
View File

@@ -20,6 +20,11 @@ func (m *mockChunkCache) GetChunk(fileId string, minSize uint64) (data []byte) {
}
return data
}
func(m *mockChunkCache) GetChunkSlice(fileId string, offset, length uint64) []byte {
return nil
}
func (m *mockChunkCache) SetChunk(fileId string, data []byte) {
}