64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
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package openfiletable
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import (
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"sync"
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"syscall"
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)
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// UINT64_MAX = 18446744073709551615
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const inumTranslateBase = 10000000000000000000
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// InumMap ... see NewInumMap() for description.
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type InumMap struct {
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sync.Mutex
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baseDev uint64
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translate map[QIno]uint64
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translateNext uint64
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}
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// NewInumMap returns a new inumMap.
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//
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// inumMap translates (device uint64, inode uint64) pairs to unique uint64
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// inode numbers.
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// Inode numbers on the "baseDev" are passed through unchanged (as long as they
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// are not higher than inumTranslateBase).
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// Inode numbers on other devices are remapped to the number space above
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// 10000000000000000000. The mapping is stored in a simple Go map. Entries
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// can only be added and are never removed.
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func NewInumMap(baseDev uint64) *InumMap {
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return &InumMap{
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baseDev: baseDev,
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translate: make(map[QIno]uint64),
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translateNext: inumTranslateBase,
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}
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}
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// Translate maps the passed-in (device, inode) pair to a unique inode number.
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func (m *InumMap) Translate(in QIno) (out uint64) {
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if in.Dev == m.baseDev && in.Ino < inumTranslateBase {
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return in.Ino
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}
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m.Lock()
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defer m.Unlock()
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out = m.translate[in]
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if out != 0 {
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return out
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}
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out = m.translateNext
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m.translate[in] = m.translateNext
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m.translateNext++
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return out
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}
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// TranslateStat translates the inode number contained in "st" if neccessary.
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// Convience wrapper around Translate().
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func (m *InumMap) TranslateStat(st *syscall.Stat_t) {
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in := QInoFromStat(st)
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st.Ino = m.Translate(in)
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}
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// Count returns the number of entries in the translation table.
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func (m *InumMap) Count() int {
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return len(m.translate)
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}
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