fix: rebalance upon pool expansion would crash when in progress (#20004)

you can attempt a rebalance first i.e, start with 2 pools.

```
mc admin rebalance start alias/
```

and after that you can add a new pool, this would
potentially crash.

```
Jun 27 09:22:19 xxx minio[7828]: panic: runtime error: invalid memory address or nil pointer dereference
Jun 27 09:22:19 xxx minio[7828]: [signal SIGSEGV: segmentation violation code=0x1 addr=0x58 pc=0x22cc225]
Jun 27 09:22:19 xxx minio[7828]: goroutine 1 [running]:
Jun 27 09:22:19 xxx minio[7828]: github.com/minio/minio/cmd.(*erasureServerPools).findIndex(...)
```
This commit is contained in:
Harshavardhana 2024-06-27 11:35:34 -07:00 committed by GitHub
parent b35d083872
commit 709612cb37
No known key found for this signature in database
GPG key ID: B5690EEEBB952194

View file

@ -119,11 +119,8 @@ func (z *erasureServerPools) loadRebalanceMeta(ctx context.Context) error {
}
z.rebalMu.Lock()
if len(r.PoolStats) == len(z.serverPools) {
z.rebalMeta = r
} else {
z.updateRebalanceStats(ctx)
}
z.rebalMeta = r
z.updateRebalanceStats(ctx)
z.rebalMu.Unlock()
return nil
@ -147,24 +144,16 @@ func (z *erasureServerPools) updateRebalanceStats(ctx context.Context) error {
}
}
if ok {
lock := z.serverPools[0].NewNSLock(minioMetaBucket, rebalMetaName)
lkCtx, err := lock.GetLock(ctx, globalOperationTimeout)
if err != nil {
rebalanceLogIf(ctx, fmt.Errorf("failed to acquire write lock on %s/%s: %w", minioMetaBucket, rebalMetaName, err))
return err
}
defer lock.Unlock(lkCtx)
ctx = lkCtx.Context()
noLockOpts := ObjectOptions{NoLock: true}
return z.rebalMeta.saveWithOpts(ctx, z.serverPools[0], noLockOpts)
return z.rebalMeta.save(ctx, z.serverPools[0])
}
return nil
}
func (z *erasureServerPools) findIndex(index int) int {
if z.rebalMeta == nil {
return 0
}
for i := 0; i < len(z.rebalMeta.PoolStats); i++ {
if i == index {
return index
@ -277,6 +266,10 @@ func (z *erasureServerPools) bucketRebalanceDone(bucket string, poolIdx int) {
z.rebalMu.Lock()
defer z.rebalMu.Unlock()
if z.rebalMeta == nil {
return
}
ps := z.rebalMeta.PoolStats[poolIdx]
if ps == nil {
return
@ -331,6 +324,10 @@ func (r *rebalanceMeta) loadWithOpts(ctx context.Context, store objectIO, opts O
}
func (r *rebalanceMeta) saveWithOpts(ctx context.Context, store objectIO, opts ObjectOptions) error {
if r == nil {
return nil
}
data := make([]byte, 4, r.Msgsize()+4)
// Initialize the header.
@ -369,7 +366,7 @@ func (z *erasureServerPools) IsPoolRebalancing(poolIndex int) bool {
if !r.StoppedAt.IsZero() {
return false
}
ps := z.rebalMeta.PoolStats[poolIndex]
ps := r.PoolStats[poolIndex]
return ps.Participating && ps.Info.Status == rebalStarted
}
return false
@ -794,7 +791,9 @@ func (z *erasureServerPools) saveRebalanceStats(ctx context.Context, poolIdx int
case rebalSaveStoppedAt:
r.StoppedAt = time.Now()
case rebalSaveStats:
r.PoolStats[poolIdx] = z.rebalMeta.PoolStats[poolIdx]
if z.rebalMeta != nil {
r.PoolStats[poolIdx] = z.rebalMeta.PoolStats[poolIdx]
}
}
z.rebalMeta = r