diff options
Diffstat (limited to 'vendor/github.com/boltdb/bolt/db.go')
| -rw-r--r-- | vendor/github.com/boltdb/bolt/db.go | 86 |
1 files changed, 66 insertions, 20 deletions
diff --git a/vendor/github.com/boltdb/bolt/db.go b/vendor/github.com/boltdb/bolt/db.go index 501d36aac2..f352ff14fe 100644 --- a/vendor/github.com/boltdb/bolt/db.go +++ b/vendor/github.com/boltdb/bolt/db.go @@ -36,6 +36,9 @@ const ( DefaultAllocSize = 16 * 1024 * 1024 ) +// default page size for db is set to the OS page size. +var defaultPageSize = os.Getpagesize() + // DB represents a collection of buckets persisted to a file on disk. // All data access is performed through transactions which can be obtained through the DB. // All the functions on DB will return a ErrDatabaseNotOpen if accessed before Open() is called. @@ -94,7 +97,7 @@ type DB struct { path string file *os.File lockfile *os.File // windows only - dataref []byte // mmap'ed readonly, write throws SEGV + dataref []byte // mmap'ed readonly, write throws SEGV data *[maxMapSize]byte datasz int filesz int // current on disk file size @@ -107,6 +110,8 @@ type DB struct { freelist *freelist stats Stats + pagePool sync.Pool + batchMu sync.Mutex batch *batch @@ -200,12 +205,27 @@ func Open(path string, mode os.FileMode, options *Options) (*DB, error) { if _, err := db.file.ReadAt(buf[:], 0); err == nil { m := db.pageInBuffer(buf[:], 0).meta() if err := m.validate(); err != nil { - return nil, err + // If we can't read the page size, we can assume it's the same + // as the OS -- since that's how the page size was chosen in the + // first place. + // + // If the first page is invalid and this OS uses a different + // page size than what the database was created with then we + // are out of luck and cannot access the database. + db.pageSize = os.Getpagesize() + } else { + db.pageSize = int(m.pageSize) } - db.pageSize = int(m.pageSize) } } + // Initialize page pool. + db.pagePool = sync.Pool{ + New: func() interface{} { + return make([]byte, db.pageSize) + }, + } + // Memory map the data file. if err := db.mmap(options.InitialMmapSize); err != nil { _ = db.close() @@ -262,12 +282,13 @@ func (db *DB) mmap(minsz int) error { db.meta0 = db.page(0).meta() db.meta1 = db.page(1).meta() - // Validate the meta pages. - if err := db.meta0.validate(); err != nil { - return err - } - if err := db.meta1.validate(); err != nil { - return err + // Validate the meta pages. We only return an error if both meta pages fail + // validation, since meta0 failing validation means that it wasn't saved + // properly -- but we can recover using meta1. And vice-versa. + err0 := db.meta0.validate() + err1 := db.meta1.validate() + if err0 != nil && err1 != nil { + return err0 } return nil @@ -339,6 +360,7 @@ func (db *DB) init() error { m.root = bucket{root: 3} m.pgid = 4 m.txid = txid(i) + m.checksum = m.sum64() } // Write an empty freelist at page 3. @@ -383,11 +405,10 @@ func (db *DB) close() error { if !db.opened { return nil } - + db.opened = false db.freelist = nil - db.path = "" // Clear ops. db.ops.writeAt = nil @@ -414,6 +435,7 @@ func (db *DB) close() error { db.file = nil } + db.path = "" return nil } @@ -530,7 +552,10 @@ func (db *DB) removeTx(tx *Tx) { // Remove the transaction. for i, t := range db.txs { if t == tx { - db.txs = append(db.txs[:i], db.txs[i+1:]...) + last := len(db.txs) - 1 + db.txs[i] = db.txs[last] + db.txs[last] = nil + db.txs = db.txs[:last] break } } @@ -778,16 +803,37 @@ func (db *DB) pageInBuffer(b []byte, id pgid) *page { // meta retrieves the current meta page reference. func (db *DB) meta() *meta { - if db.meta0.txid > db.meta1.txid { - return db.meta0 + // We have to return the meta with the highest txid which doesn't fail + // validation. Otherwise, we can cause errors when in fact the database is + // in a consistent state. metaA is the one with the higher txid. + metaA := db.meta0 + metaB := db.meta1 + if db.meta1.txid > db.meta0.txid { + metaA = db.meta1 + metaB = db.meta0 + } + + // Use higher meta page if valid. Otherwise fallback to previous, if valid. + if err := metaA.validate(); err == nil { + return metaA + } else if err := metaB.validate(); err == nil { + return metaB } - return db.meta1 + + // This should never be reached, because both meta1 and meta0 were validated + // on mmap() and we do fsync() on every write. + panic("bolt.DB.meta(): invalid meta pages") } // allocate returns a contiguous block of memory starting at a given page. func (db *DB) allocate(count int) (*page, error) { // Allocate a temporary buffer for the page. - buf := make([]byte, count*db.pageSize) + var buf []byte + if count == 1 { + buf = db.pagePool.Get().([]byte) + } else { + buf = make([]byte, count*db.pageSize) + } p := (*page)(unsafe.Pointer(&buf[0])) p.overflow = uint32(count - 1) @@ -909,7 +955,7 @@ func (s *Stats) Sub(other *Stats) Stats { diff.PendingPageN = s.PendingPageN diff.FreeAlloc = s.FreeAlloc diff.FreelistInuse = s.FreelistInuse - diff.TxN = other.TxN - s.TxN + diff.TxN = s.TxN - other.TxN diff.TxStats = s.TxStats.Sub(&other.TxStats) return diff } @@ -937,12 +983,12 @@ type meta struct { // validate checks the marker bytes and version of the meta page to ensure it matches this binary. func (m *meta) validate() error { - if m.checksum != 0 && m.checksum != m.sum64() { - return ErrChecksum - } else if m.magic != magic { + if m.magic != magic { return ErrInvalid } else if m.version != version { return ErrVersionMismatch + } else if m.checksum != 0 && m.checksum != m.sum64() { + return ErrChecksum } return nil } |