Merge branch '15964-fix-docs' refs #15964
[arvados.git] / sdk / go / arvados / fs_collection.go
index cd3dcf053942a4df8c858c550828608081ab5cbf..060b57b493cbf555d4d87d9b71db4f6171ff85b8 100644 (file)
@@ -16,12 +16,14 @@ import (
        "strconv"
        "strings"
        "sync"
+       "sync/atomic"
        "time"
 )
 
-var maxBlockSize = 1 << 26
-
-var concurrentWriters = 4
+var (
+       maxBlockSize      = 1 << 26
+       concurrentWriters = 4 // max goroutines writing to Keep in background and during flush()
+)
 
 // A CollectionFileSystem is a FileSystem that can be serialized as a
 // manifest and stored as a collection.
@@ -36,6 +38,9 @@ type CollectionFileSystem interface {
 
        // Total data bytes in all files.
        Size() int64
+
+       // Memory consumed by buffered file data.
+       memorySize() int64
 }
 
 type collectionFileSystem struct {
@@ -45,16 +50,15 @@ type collectionFileSystem struct {
 
 // FileSystem returns a CollectionFileSystem for the collection.
 func (c *Collection) FileSystem(client apiClient, kc keepClient) (CollectionFileSystem, error) {
-       var modTime time.Time
-       if c.ModifiedAt == nil {
+       modTime := c.ModifiedAt
+       if modTime.IsZero() {
                modTime = time.Now()
-       } else {
-               modTime = *c.ModifiedAt
        }
        fs := &collectionFileSystem{
                uuid: c.UUID,
                fileSystem: fileSystem{
                        fsBackend: keepBackend{apiClient: client, keepClient: kc},
+                       thr:       newThrottle(concurrentWriters),
                },
        }
        root := &dirnode{
@@ -117,6 +121,62 @@ func (fs *collectionFileSystem) newNode(name string, perm os.FileMode, modTime t
        }
 }
 
+func (fs *collectionFileSystem) Child(name string, replace func(inode) (inode, error)) (inode, error) {
+       return fs.rootnode().Child(name, replace)
+}
+
+func (fs *collectionFileSystem) FS() FileSystem {
+       return fs
+}
+
+func (fs *collectionFileSystem) FileInfo() os.FileInfo {
+       return fs.rootnode().FileInfo()
+}
+
+func (fs *collectionFileSystem) IsDir() bool {
+       return true
+}
+
+func (fs *collectionFileSystem) Lock() {
+       fs.rootnode().Lock()
+}
+
+func (fs *collectionFileSystem) Unlock() {
+       fs.rootnode().Unlock()
+}
+
+func (fs *collectionFileSystem) RLock() {
+       fs.rootnode().RLock()
+}
+
+func (fs *collectionFileSystem) RUnlock() {
+       fs.rootnode().RUnlock()
+}
+
+func (fs *collectionFileSystem) Parent() inode {
+       return fs.rootnode().Parent()
+}
+
+func (fs *collectionFileSystem) Read(_ []byte, ptr filenodePtr) (int, filenodePtr, error) {
+       return 0, ptr, ErrInvalidOperation
+}
+
+func (fs *collectionFileSystem) Write(_ []byte, ptr filenodePtr) (int, filenodePtr, error) {
+       return 0, ptr, ErrInvalidOperation
+}
+
+func (fs *collectionFileSystem) Readdir() ([]os.FileInfo, error) {
+       return fs.rootnode().Readdir()
+}
+
+func (fs *collectionFileSystem) SetParent(parent inode, name string) {
+       fs.rootnode().SetParent(parent, name)
+}
+
+func (fs *collectionFileSystem) Truncate(int64) error {
+       return ErrInvalidOperation
+}
+
 func (fs *collectionFileSystem) Sync() error {
        if fs.uuid == "" {
                return nil
@@ -129,17 +189,60 @@ func (fs *collectionFileSystem) Sync() error {
                UUID:         fs.uuid,
                ManifestText: txt,
        }
-       err = fs.RequestAndDecode(nil, "PUT", "arvados/v1/collections/"+fs.uuid, fs.UpdateBody(coll), map[string]interface{}{"select": []string{"uuid"}})
+       err = fs.RequestAndDecode(nil, "PUT", "arvados/v1/collections/"+fs.uuid, nil, map[string]interface{}{
+               "collection": map[string]string{
+                       "manifest_text": coll.ManifestText,
+               },
+               "select": []string{"uuid"},
+       })
        if err != nil {
                return fmt.Errorf("sync failed: update %s: %s", fs.uuid, err)
        }
        return nil
 }
 
+func (fs *collectionFileSystem) Flush(path string, shortBlocks bool) error {
+       node, err := rlookup(fs.fileSystem.root, path)
+       if err != nil {
+               return err
+       }
+       dn, ok := node.(*dirnode)
+       if !ok {
+               return ErrNotADirectory
+       }
+       dn.Lock()
+       defer dn.Unlock()
+       names := dn.sortedNames()
+       if path != "" {
+               // Caller only wants to flush the specified dir,
+               // non-recursively.  Drop subdirs from the list of
+               // names.
+               var filenames []string
+               for _, name := range names {
+                       if _, ok := dn.inodes[name].(*filenode); ok {
+                               filenames = append(filenames, name)
+                       }
+               }
+               names = filenames
+       }
+       for _, name := range names {
+               child := dn.inodes[name]
+               child.Lock()
+               defer child.Unlock()
+       }
+       return dn.flush(context.TODO(), names, flushOpts{sync: false, shortBlocks: shortBlocks})
+}
+
+func (fs *collectionFileSystem) memorySize() int64 {
+       fs.fileSystem.root.Lock()
+       defer fs.fileSystem.root.Unlock()
+       return fs.fileSystem.root.(*dirnode).memorySize()
+}
+
 func (fs *collectionFileSystem) MarshalManifest(prefix string) (string, error) {
        fs.fileSystem.root.Lock()
        defer fs.fileSystem.root.Unlock()
-       return fs.fileSystem.root.(*dirnode).marshalManifest(context.TODO(), prefix, newThrottle(concurrentWriters))
+       return fs.fileSystem.root.(*dirnode).marshalManifest(context.TODO(), prefix)
 }
 
 func (fs *collectionFileSystem) Size() int64 {
@@ -231,7 +334,6 @@ type filenode struct {
        memsize  int64 // bytes in memSegments
        sync.RWMutex
        nullnode
-       throttle *throttle
 }
 
 // caller must have lock
@@ -466,8 +568,6 @@ func (fn *filenode) Write(p []byte, startPtr filenodePtr) (n int, ptr filenodePt
                                seg.Truncate(len(cando))
                                fn.memsize += int64(len(cando))
                                fn.segments[cur] = seg
-                               cur++
-                               prev++
                        }
                }
 
@@ -494,15 +594,11 @@ func (fn *filenode) Write(p []byte, startPtr filenodePtr) (n int, ptr filenodePt
 // Write some data out to disk to reduce memory use. Caller must have
 // write lock.
 func (fn *filenode) pruneMemSegments() {
-       // TODO: share code with (*dirnode)sync()
+       // TODO: share code with (*dirnode)flush()
        // TODO: pack/flush small blocks too, when fragmented
-       if fn.throttle == nil {
-               // TODO: share a throttle with filesystem
-               fn.throttle = newThrottle(concurrentWriters)
-       }
        for idx, seg := range fn.segments {
                seg, ok := seg.(*memSegment)
-               if !ok || seg.Len() < maxBlockSize || seg.Len() == 0 || seg.flushing != nil {
+               if !ok || seg.Len() < maxBlockSize || seg.flushing != nil {
                        continue
                }
                // Setting seg.flushing guarantees seg.buf will not be
@@ -515,18 +611,17 @@ func (fn *filenode) pruneMemSegments() {
                // progress, block here until one finishes, rather
                // than pile up an unlimited number of buffered writes
                // and network flush operations.
-               fn.throttle.Acquire()
+               fn.fs.throttle().Acquire()
                go func() {
                        defer close(done)
                        locator, _, err := fn.FS().PutB(buf)
-                       fn.throttle.Release()
+                       fn.fs.throttle().Release()
                        fn.Lock()
                        defer fn.Unlock()
-                       if curbuf := seg.buf[:1]; &curbuf[0] != &buf[0] {
+                       if seg.flushing != done {
                                // A new seg.buf has been allocated.
                                return
                        }
-                       seg.flushing = nil
                        if err != nil {
                                // TODO: stall (or return errors from)
                                // subsequent writes until flushing
@@ -549,8 +644,8 @@ func (fn *filenode) pruneMemSegments() {
        }
 }
 
-// Block until all pending pruneMemSegments work is finished. Caller
-// must NOT have lock.
+// Block until all pending pruneMemSegments/flush work is
+// finished. Caller must NOT have lock.
 func (fn *filenode) waitPrune() {
        var pending []<-chan struct{}
        fn.Lock()
@@ -595,103 +690,230 @@ func (dn *dirnode) Child(name string, replace func(inode) (inode, error)) (inode
        return dn.treenode.Child(name, replace)
 }
 
-// sync flushes in-memory data and remote block references (for the
-// children with the given names, which must be children of dn) to
-// local persistent storage. Caller must have write lock on dn and the
-// named children.
-func (dn *dirnode) sync(ctx context.Context, names []string, throttle *throttle) error {
-       cg := newContextGroup(ctx)
-       defer cg.Cancel()
+type fnSegmentRef struct {
+       fn  *filenode
+       idx int
+}
 
-       type shortBlock struct {
-               fn  *filenode
-               idx int
+// commitBlock concatenates the data from the given filenode segments
+// (which must be *memSegments), writes the data out to Keep as a
+// single block, and replaces the filenodes' *memSegments with
+// storedSegments that reference the relevant portions of the new
+// block.
+//
+// bufsize is the total data size in refs. It is used to preallocate
+// the correct amount of memory when len(refs)>1.
+//
+// If sync is false, commitBlock returns right away, after starting a
+// goroutine to do the writes, reacquire the filenodes' locks, and
+// swap out the *memSegments. Some filenodes' segments might get
+// modified/rearranged in the meantime, in which case commitBlock
+// won't replace them.
+//
+// Caller must have write lock.
+func (dn *dirnode) commitBlock(ctx context.Context, refs []fnSegmentRef, bufsize int, sync bool) error {
+       if len(refs) == 0 {
+               return nil
        }
-
-       flush := func(sbs []shortBlock) error {
-               if len(sbs) == 0 {
+       if err := ctx.Err(); err != nil {
+               return err
+       }
+       done := make(chan struct{})
+       var block []byte
+       segs := make([]*memSegment, 0, len(refs))
+       offsets := make([]int, 0, len(refs)) // location of segment's data within block
+       for _, ref := range refs {
+               seg := ref.fn.segments[ref.idx].(*memSegment)
+               if !sync && seg.flushingUnfinished() {
+                       // Let the other flushing goroutine finish. If
+                       // it fails, we'll try again next time.
+                       close(done)
                        return nil
+               } else {
+                       // In sync mode, we proceed regardless of
+                       // whether another flush is in progress: It
+                       // can't finish before we do, because we hold
+                       // fn's lock until we finish our own writes.
                }
-               throttle.Acquire()
-               defer throttle.Release()
-               if err := cg.Context().Err(); err != nil {
-                       return err
-               }
-               block := make([]byte, 0, maxBlockSize)
-               for _, sb := range sbs {
-                       block = append(block, sb.fn.segments[sb.idx].(*memSegment).buf...)
+               seg.flushing = done
+               offsets = append(offsets, len(block))
+               if len(refs) == 1 {
+                       block = seg.buf
+               } else if block == nil {
+                       block = append(make([]byte, 0, bufsize), seg.buf...)
+               } else {
+                       block = append(block, seg.buf...)
                }
+               segs = append(segs, seg)
+       }
+       blocksize := len(block)
+       dn.fs.throttle().Acquire()
+       errs := make(chan error, 1)
+       go func() {
+               defer close(done)
+               defer close(errs)
                locator, _, err := dn.fs.PutB(block)
+               dn.fs.throttle().Release()
                if err != nil {
-                       return err
+                       errs <- err
+                       return
                }
-               off := 0
-               for _, sb := range sbs {
-                       data := sb.fn.segments[sb.idx].(*memSegment).buf
-                       sb.fn.segments[sb.idx] = storedSegment{
+               for idx, ref := range refs {
+                       if !sync {
+                               ref.fn.Lock()
+                               // In async mode, fn's lock was
+                               // released while we were waiting for
+                               // PutB(); lots of things might have
+                               // changed.
+                               if len(ref.fn.segments) <= ref.idx {
+                                       // file segments have
+                                       // rearranged or changed in
+                                       // some way
+                                       ref.fn.Unlock()
+                                       continue
+                               } else if seg, ok := ref.fn.segments[ref.idx].(*memSegment); !ok || seg != segs[idx] {
+                                       // segment has been replaced
+                                       ref.fn.Unlock()
+                                       continue
+                               } else if seg.flushing != done {
+                                       // seg.buf has been replaced
+                                       ref.fn.Unlock()
+                                       continue
+                               }
+                       }
+                       data := ref.fn.segments[ref.idx].(*memSegment).buf
+                       ref.fn.segments[ref.idx] = storedSegment{
                                kc:      dn.fs,
                                locator: locator,
-                               size:    len(block),
-                               offset:  off,
+                               size:    blocksize,
+                               offset:  offsets[idx],
                                length:  len(data),
                        }
-                       off += len(data)
-                       sb.fn.memsize -= int64(len(data))
+                       // atomic is needed here despite caller having
+                       // lock: caller might be running concurrent
+                       // commitBlock() goroutines using the same
+                       // lock, writing different segments from the
+                       // same file.
+                       atomic.AddInt64(&ref.fn.memsize, -int64(len(data)))
+                       if !sync {
+                               ref.fn.Unlock()
+                       }
                }
+       }()
+       if sync {
+               return <-errs
+       } else {
                return nil
        }
+}
+
+type flushOpts struct {
+       sync        bool
+       shortBlocks bool
+}
+
+// flush in-memory data and remote-cluster block references (for the
+// children with the given names, which must be children of dn) to
+// local-cluster persistent storage.
+//
+// Caller must have write lock on dn and the named children.
+//
+// If any children are dirs, they will be flushed recursively.
+func (dn *dirnode) flush(ctx context.Context, names []string, opts flushOpts) error {
+       cg := newContextGroup(ctx)
+       defer cg.Cancel()
 
-       goFlush := func(sbs []shortBlock) {
+       goCommit := func(refs []fnSegmentRef, bufsize int) {
                cg.Go(func() error {
-                       return flush(sbs)
+                       return dn.commitBlock(cg.Context(), refs, bufsize, opts.sync)
                })
        }
 
-       var pending []shortBlock
-       var pendingLen int
+       var pending []fnSegmentRef
+       var pendingLen int = 0
        localLocator := map[string]string{}
        for _, name := range names {
-               fn, ok := dn.inodes[name].(*filenode)
-               if !ok {
-                       continue
-               }
-               for idx, seg := range fn.segments {
-                       switch seg := seg.(type) {
-                       case storedSegment:
-                               loc, ok := localLocator[seg.locator]
-                               if !ok {
-                                       var err error
-                                       loc, err = dn.fs.LocalLocator(seg.locator)
-                                       if err != nil {
-                                               return err
+               switch node := dn.inodes[name].(type) {
+               case *dirnode:
+                       grandchildNames := node.sortedNames()
+                       for _, grandchildName := range grandchildNames {
+                               grandchild := node.inodes[grandchildName]
+                               grandchild.Lock()
+                               defer grandchild.Unlock()
+                       }
+                       cg.Go(func() error { return node.flush(cg.Context(), grandchildNames, opts) })
+               case *filenode:
+                       for idx, seg := range node.segments {
+                               switch seg := seg.(type) {
+                               case storedSegment:
+                                       loc, ok := localLocator[seg.locator]
+                                       if !ok {
+                                               var err error
+                                               loc, err = dn.fs.LocalLocator(seg.locator)
+                                               if err != nil {
+                                                       return err
+                                               }
+                                               localLocator[seg.locator] = loc
                                        }
-                                       localLocator[seg.locator] = loc
-                               }
-                               seg.locator = loc
-                               fn.segments[idx] = seg
-                       case *memSegment:
-                               if seg.Len() > maxBlockSize/2 {
-                                       goFlush([]shortBlock{{fn, idx}})
-                                       continue
-                               }
-                               if pendingLen+seg.Len() > maxBlockSize {
-                                       goFlush(pending)
-                                       pending = nil
-                                       pendingLen = 0
+                                       seg.locator = loc
+                                       node.segments[idx] = seg
+                               case *memSegment:
+                                       if seg.Len() > maxBlockSize/2 {
+                                               goCommit([]fnSegmentRef{{node, idx}}, seg.Len())
+                                               continue
+                                       }
+                                       if pendingLen+seg.Len() > maxBlockSize {
+                                               goCommit(pending, pendingLen)
+                                               pending = nil
+                                               pendingLen = 0
+                                       }
+                                       pending = append(pending, fnSegmentRef{node, idx})
+                                       pendingLen += seg.Len()
+                               default:
+                                       panic(fmt.Sprintf("can't sync segment type %T", seg))
                                }
-                               pending = append(pending, shortBlock{fn, idx})
-                               pendingLen += seg.Len()
-                       default:
-                               panic(fmt.Sprintf("can't sync segment type %T", seg))
                        }
                }
        }
-       goFlush(pending)
+       if opts.shortBlocks {
+               goCommit(pending, pendingLen)
+       }
        return cg.Wait()
 }
 
 // caller must have write lock.
-func (dn *dirnode) marshalManifest(ctx context.Context, prefix string, throttle *throttle) (string, error) {
+func (dn *dirnode) memorySize() (size int64) {
+       for _, name := range dn.sortedNames() {
+               node := dn.inodes[name]
+               node.Lock()
+               defer node.Unlock()
+               switch node := node.(type) {
+               case *dirnode:
+                       size += node.memorySize()
+               case *filenode:
+                       for _, seg := range node.segments {
+                               switch seg := seg.(type) {
+                               case *memSegment:
+                                       size += int64(seg.Len())
+                               }
+                       }
+               }
+       }
+       return
+}
+
+// caller must have write lock.
+func (dn *dirnode) sortedNames() []string {
+       names := make([]string, 0, len(dn.inodes))
+       for name := range dn.inodes {
+               names = append(names, name)
+       }
+       sort.Strings(names)
+       return names
+}
+
+// caller must have write lock.
+func (dn *dirnode) marshalManifest(ctx context.Context, prefix string) (string, error) {
        cg := newContextGroup(ctx)
        defer cg.Cancel()
 
@@ -706,11 +928,7 @@ func (dn *dirnode) marshalManifest(ctx context.Context, prefix string, throttle
                return manifestEscape(prefix) + " d41d8cd98f00b204e9800998ecf8427e+0 0:0:\\056\n", nil
        }
 
-       names := make([]string, 0, len(dn.inodes))
-       for name := range dn.inodes {
-               names = append(names, name)
-       }
-       sort.Strings(names)
+       names := dn.sortedNames()
 
        // Wait for children to finish any pending write operations
        // before locking them.
@@ -742,7 +960,7 @@ func (dn *dirnode) marshalManifest(ctx context.Context, prefix string, throttle
        for i, name := range dirnames {
                i, name := i, name
                cg.Go(func() error {
-                       txt, err := dn.inodes[name].(*dirnode).marshalManifest(cg.Context(), prefix+"/"+name, throttle)
+                       txt, err := dn.inodes[name].(*dirnode).marshalManifest(cg.Context(), prefix+"/"+name)
                        subdirs[i] = txt
                        return err
                })
@@ -758,7 +976,7 @@ func (dn *dirnode) marshalManifest(ctx context.Context, prefix string, throttle
 
                var fileparts []filepart
                var blocks []string
-               if err := dn.sync(cg.Context(), names, throttle); err != nil {
+               if err := dn.flush(cg.Context(), filenames, flushOpts{sync: true, shortBlocks: true}); err != nil {
                        return err
                }
                for _, name := range filenames {
@@ -791,7 +1009,7 @@ func (dn *dirnode) marshalManifest(ctx context.Context, prefix string, throttle
                                default:
                                        // This can't happen: we
                                        // haven't unlocked since
-                                       // calling sync().
+                                       // calling flush(sync=true).
                                        panic(fmt.Sprintf("can't marshal segment type %T", seg))
                                }
                        }
@@ -889,9 +1107,9 @@ func (dn *dirnode) loadManifest(txt string) error {
                                // situation might be rare anyway)
                                segIdx, pos = 0, 0
                        }
-                       for next := int64(0); segIdx < len(segments); segIdx++ {
+                       for ; segIdx < len(segments); segIdx++ {
                                seg := segments[segIdx]
-                               next = pos + int64(seg.Len())
+                               next := pos + int64(seg.Len())
                                if next <= offset || seg.Len() == 0 {
                                        pos = next
                                        continue
@@ -1025,13 +1243,26 @@ type segment interface {
 
 type memSegment struct {
        buf []byte
-       // If flushing is not nil, then a) buf is being shared by a
-       // pruneMemSegments goroutine, and must be copied on write;
-       // and b) the flushing channel will close when the goroutine
-       // finishes, whether it succeeds or not.
+       // If flushing is not nil and not ready/closed, then a) buf is
+       // being shared by a pruneMemSegments goroutine, and must be
+       // copied on write; and b) the flushing channel will close
+       // when the goroutine finishes, whether it succeeds or not.
        flushing <-chan struct{}
 }
 
+func (me *memSegment) flushingUnfinished() bool {
+       if me.flushing == nil {
+               return false
+       }
+       select {
+       case <-me.flushing:
+               me.flushing = nil
+               return false
+       default:
+               return true
+       }
+}
+
 func (me *memSegment) Len() int {
        return len(me.buf)
 }