X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/a3c509e8eca36f1291f7547999f16d9fd127c4a0..0f5b0542513b572959e39400bae42e69aeb1a7b6:/sdk/go/arvados/fs_base.go

diff --git a/sdk/go/arvados/fs_base.go b/sdk/go/arvados/fs_base.go
index 5bccdc51db..274d207022 100644
--- a/sdk/go/arvados/fs_base.go
+++ b/sdk/go/arvados/fs_base.go
@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"log"
 	"net/http"
 	"os"
@@ -81,10 +82,13 @@ type File interface {
 	// then be spliced onto a different path or a different
 	// collection.
 	Snapshot() (*Subtree, error)
-	// Replace this file or directory with the given snapshot. It
-	// is an error to replace a directory with a file. If snapshot
-	// is (or might be) a directory, remove the directory, create
-	// a file with the same name, and splice the file.
+	// Replace this file or directory with the given snapshot.
+	// The target must be inside a collection: Splice returns an
+	// error if the File is a virtual file or directory like
+	// by_id, a project directory, .arvados#collection,
+	// etc. Splice can replace directories with regular files and
+	// vice versa, except it cannot replace the root directory of
+	// a collection with a regular file.
 	Splice(snapshot *Subtree) error
 }
 
@@ -156,6 +160,18 @@ type FileSystem interface {
 	MemorySize() int64
 }
 
+type fsFS struct {
+	FileSystem
+}
+
+// FS returns an fs.FS interface to the given FileSystem, to enable
+// the use of fs.WalkDir, etc.
+func FS(fs FileSystem) fs.FS { return fsFS{fs} }
+func (fs fsFS) Open(path string) (fs.File, error) {
+	f, err := fs.FileSystem.Open(path)
+	return f, err
+}
+
 type inode interface {
 	SetParent(parent inode, name string)
 	Parent() inode
@@ -171,7 +187,7 @@ type inode interface {
 	Snapshot() (inode, error)
 	// Replace this node with a copy of the provided snapshot.
 	// Caller may provide the same snapshot to multiple Splice
-	// calls, but must not modify the the snapshot concurrently.
+	// calls, but must not modify the snapshot concurrently.
 	Splice(inode) error
 
 	// Child() performs lookups and updates of named child nodes.
@@ -218,6 +234,14 @@ type fileinfo struct {
 	mode    os.FileMode
 	size    int64
 	modTime time.Time
+	// If not nil, sys() returns the source data structure, which
+	// can be a *Collection, *Group, or nil. Currently populated
+	// only for project dirs and top-level collection dirs. Does
+	// not stay up to date with upstream changes.
+	//
+	// Intended to support keep-web's properties-as-s3-metadata
+	// feature (https://dev.arvados.org/issues/19088).
+	sys func() interface{}
 }
 
 // Name implements os.FileInfo.
@@ -245,9 +269,12 @@ func (fi fileinfo) Size() int64 {
 	return fi.size
 }
 
-// Sys implements os.FileInfo.
+// Sys implements os.FileInfo. See comment in fileinfo struct.
 func (fi fileinfo) Sys() interface{} {
-	return nil
+	if fi.sys == nil {
+		return nil
+	}
+	return fi.sys()
 }
 
 type nullnode struct{}
@@ -393,13 +420,23 @@ func (n *treenode) Sync() error {
 }
 
 func (n *treenode) MemorySize() (size int64) {
+	// To avoid making other callers wait while we count the
+	// entire filesystem size, we lock the node only long enough
+	// to copy the list of children. We accept that the resulting
+	// size will sometimes be misleading (e.g., we will
+	// double-count an item that moves from A to B after we check
+	// A's size but before we check B's size).
 	n.RLock()
-	defer n.RUnlock()
 	debugPanicIfNotLocked(n, false)
+	todo := make([]inode, 0, len(n.inodes))
 	for _, inode := range n.inodes {
+		todo = append(todo, inode)
+	}
+	n.RUnlock()
+	for _, inode := range todo {
 		size += inode.MemorySize()
 	}
-	return
+	return 64 + size
 }
 
 type fileSystem struct {
@@ -447,14 +484,14 @@ func (fs *fileSystem) openFile(name string, flag int, perm os.FileMode) (*fileha
 	default:
 		return nil, fmt.Errorf("invalid flags 0x%x", flag)
 	}
-	if !writable && parent.IsDir() {
+	if parent.IsDir() {
 		// A directory can be opened via "foo/", "foo/.", or
 		// "foo/..".
 		switch name {
 		case ".", "":
-			return &filehandle{inode: parent}, nil
+			return &filehandle{inode: parent, readable: readable, writable: writable}, nil
 		case "..":
-			return &filehandle{inode: parent.Parent()}, nil
+			return &filehandle{inode: parent.Parent(), readable: readable, writable: writable}, nil
 		}
 	}
 	createMode := flag&os.O_CREATE != 0
@@ -604,7 +641,15 @@ func (fs *fileSystem) Rename(oldname, newname string) error {
 	}
 	locked := map[sync.Locker]bool{}
 	for i := len(needLock) - 1; i >= 0; i-- {
-		if n := needLock[i]; !locked[n] {
+		n := needLock[i]
+		if fs, ok := n.(interface{ rootnode() inode }); ok {
+			// Lock the fs's root dir directly, not
+			// through the fs. Otherwise our "locked" map
+			// would not reliably prevent double-locking
+			// the fs's root dir.
+			n = fs.rootnode()
+		}
+		if !locked[n] {
 			n.Lock()
 			defer n.Unlock()
 			locked[n] = true
@@ -750,7 +795,7 @@ func Splice(fs FileSystem, target string, newsubtree *Subtree) error {
 		f, err = fs.OpenFile(target, os.O_CREATE|os.O_WRONLY, 0700)
 	}
 	if err != nil {
-		return err
+		return fmt.Errorf("open %s: %w", target, err)
 	}
 	defer f.Close()
 	return f.Splice(newsubtree)