mirror of
https://github.com/seaweedfs/seaweedfs.git
synced 2026-09-08 15:41:15 +02:00
Chris Lu
5f787a25c3
* master: survive a layout deleted twice Two volume servers dropping the last replica of volumes that share a layout both find it empty and both delete it. The loser's lookup misses, and the single-value type assertion on the result crashed the master before the caller could look at the found flag. Claude-Session: https://claude.ai/code/session_01WmX6Rchx298NQksHDXg7sk * master: remove a layout and read it back in one step DeleteVolumeLayout looked the layout up and then deleted it, so two deleters could each release the lookup ownership of the same layout, or one could find nothing to release at all. Have the map hand back what it removed. Claude-Session: https://claude.ai/code/session_01WmX6Rchx298NQksHDXg7sk
65 lines
1.4 KiB
Go
65 lines
1.4 KiB
Go
package util
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import (
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"sync"
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)
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// A mostly for read map, which can thread-safely
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// initialize the map entries.
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type ConcurrentReadMap struct {
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sync.RWMutex
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items map[string]interface{}
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}
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func NewConcurrentReadMap() *ConcurrentReadMap {
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return &ConcurrentReadMap{items: make(map[string]interface{})}
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}
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func (m *ConcurrentReadMap) initMapEntry(key string, newEntry func() interface{}) (value interface{}) {
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m.Lock()
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defer m.Unlock()
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if value, ok := m.items[key]; ok {
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return value
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}
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value = newEntry()
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m.items[key] = value
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return value
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}
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func (m *ConcurrentReadMap) Get(key string, newEntry func() interface{}) interface{} {
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m.RLock()
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if value, ok := m.items[key]; ok {
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m.RUnlock()
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return value
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}
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m.RUnlock()
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return m.initMapEntry(key, newEntry)
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}
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func (m *ConcurrentReadMap) Find(key string) (interface{}, bool) {
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m.RLock()
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value, ok := m.items[key]
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m.RUnlock()
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return value, ok
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}
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func (m *ConcurrentReadMap) Items() (itemsCopy []interface{}) {
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m.RLock()
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for _, i := range m.items {
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itemsCopy = append(itemsCopy, i)
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}
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m.RUnlock()
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return itemsCopy
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}
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// Delete removes the key and returns what it held, so a caller that has to
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// wind the entry down does not race another deleter for it.
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func (m *ConcurrentReadMap) Delete(key string) (interface{}, bool) {
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m.Lock()
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value, ok := m.items[key]
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delete(m.items, key)
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m.Unlock()
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return value, ok
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}
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