func (cfio *ChunkedFileIO) Truncate(size int64) error {
if !fl.IsReadWriteAllowed(cfio.bs.Flags()) {
return EPERM
}
cs, err := cfio.caio.Read()
if err != nil {
return fmt.Errorf("Failed to read cs array: %v", err)
}
for i := len(cs) - 1; i >= 0; i-- {
c := &cs[i]
if c.Left() >= size {
// drop the chunk
continue
}
if c.Right() > size {
// trim the chunk
chunksize := size - c.Left()
bh, err := cfio.bs.Open(c.BlobPath, fl.O_RDWR)
if err != nil {
return err
}
cio := cfio.newChunkIO(bh, cfio.c, c.Offset)
if err := cio.Truncate(chunksize); err != nil {
return err
}
if err := cio.Close(); err != nil {
return err
}
c.Length = int64(cio.Size())
}
cs = cs[:i+1]
if err := cfio.caio.Write(cs); err != nil {
return fmt.Errorf("Failed to write updated cs array: %v", err)
}
return nil
}
if err := cfio.caio.Write([]inodedb.FileChunk{}); err != nil {
return fmt.Errorf("Failed to write updated cs array (empty): %v", err)
}
return nil
}
func (cfio *ChunkedFileIO) PWrite(p []byte, offset int64) error {
logger.Debugf(mylog, "PWrite: offset=%d, len=%d", offset, len(p))
// logger.Debugf(mylog, "PWrite: p=%v", p)
remo := offset
remp := p
if len(remp) == 0 {
return nil
}
cs, err := cfio.caio.Read()
if err != nil {
return fmt.Errorf("Failed to read cs array: %v", err)
}
writeToChunk := func(c *inodedb.FileChunk, isNewChunk bool, maxChunkLen int64) error {
if !fl.IsReadWriteAllowed(cfio.bs.Flags()) {
return EPERM
}
flags := fl.O_RDWR
if isNewChunk {
flags |= fl.O_CREATE | fl.O_EXCL
}
bh, err := cfio.bs.Open(c.BlobPath, flags)
if err != nil {
return fmt.Errorf("Failed to open path \"%s\" for writing (isNewChunk: %t): %v", c.BlobPath, isNewChunk, err)
}
defer func() {
if err := bh.Close(); err != nil {
logger.Criticalf(mylog, "blobhandle Close failed: %v", err)
}
}()
cio := cfio.newChunkIO(bh, cfio.c, c.Offset)
defer func() {
if err := cio.Close(); err != nil {
logger.Criticalf(mylog, "cio Close failed: %v", err)
}
}()
coff := remo - c.Offset
n := util.IntMin(len(remp), int(maxChunkLen-coff))
if n < 0 {
return nil
}
if err := cio.PWrite(remp[:n], coff); err != nil {
return err
}
oldLength := c.Length
c.Length = int64(cio.Size())
if oldLength != c.Length {
if err := cfio.caio.Write(cs); err != nil {
return fmt.Errorf("Failed to write updated cs array: %v", err)
}
}
remo += int64(n)
remp = remp[n:]
return nil
}
for i := 0; i < len(cs); i++ {
c := &cs[i]
if c.Left() > remo {
// Insert a new chunk @ i
// try best to align offset at ChunkSplitSize
newo := remo / ChunkSplitSize * ChunkSplitSize
maxlen := int64(ChunkSplitSize)
if i > 0 {
prev := cs[i-1]
pright := prev.Right()
if newo < pright {
maxlen -= pright - newo
newo = pright
}
}
if i < len(cs)-1 {
next := cs[i+1]
if newo+maxlen > next.Left() {
maxlen = next.Left() - newo
}
}
newc, err := cfio.newFileChunk(newo)
if err != nil {
return err
}
cs = append(cs, inodedb.FileChunk{})
copy(cs[i+1:], cs[i:])
cs[i] = newc
if err := cfio.caio.Write(cs); err != nil {
return fmt.Errorf("Failed to write updated cs array: %v", err)
}
if err := writeToChunk(&newc, NewChunk, maxlen); err != nil {
return err
}
if len(remp) == 0 {
break
}
continue
}
// Write to the chunk
maxlen := int64(ChunkSplitSize)
if i < len(cs)-1 {
next := cs[i+1]
if c.Left()+maxlen > next.Left() {
maxlen = next.Left() - c.Left()
}
}
if err := writeToChunk(c, ExistingChunk, maxlen); err != nil {
return err
}
if len(remp) == 0 {
break
}
}
for len(remp) > 0 {
// Append a new chunk at the end
newo := remo / ChunkSplitSize * ChunkSplitSize
maxlen := int64(ChunkSplitSize)
if len(cs) > 0 {
last := cs[len(cs)-1]
lastRight := last.Right()
if newo < lastRight {
maxlen -= lastRight - newo
newo = lastRight
}
}
newc, err := cfio.newFileChunk(newo)
if err != nil {
return err
}
if err := writeToChunk(&newc, NewChunk, maxlen); err != nil {
return err
}
cs = append(cs, newc)
if err := cfio.caio.Write(cs); err != nil {
return fmt.Errorf("Failed to write updated cs array: %v", err)
}
}
return nil
}
