X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/7d4e2e418a987a454d18902a937fc91bed69ce75..32c63d03d45d231768eb1497dfc5e9f4a0d23c16:/lib/mount/fs.go

diff --git a/lib/mount/fs.go b/lib/mount/fs.go
index 5b6fc0012f..3c2e628d01 100644
--- a/lib/mount/fs.go
+++ b/lib/mount/fs.go
@@ -5,6 +5,7 @@
 package mount
 
 import (
+	"errors"
 	"io"
 	"log"
 	"os"
@@ -36,7 +37,7 @@ type keepFS struct {
 	root   arvados.CustomFileSystem
 	open   map[uint64]*sharedFile
 	lastFH uint64
-	sync.Mutex
+	sync.RWMutex
 
 	// If non-nil, this channel will be closed by Init() to notify
 	// other goroutines that the mount is ready.
@@ -62,8 +63,8 @@ func (fs *keepFS) newFH(f arvados.File) uint64 {
 }
 
 func (fs *keepFS) lookupFH(fh uint64) *sharedFile {
-	fs.Lock()
-	defer fs.Unlock()
+	fs.RLock()
+	defer fs.RUnlock()
 	return fs.open[fh]
 }
 
@@ -121,23 +122,25 @@ func (fs *keepFS) Utimens(path string, tmsp []fuse.Timespec) int {
 }
 
 func (fs *keepFS) errCode(err error) int {
-	if os.IsNotExist(err) {
+	if err == nil {
+		return 0
+	}
+	if errors.Is(err, os.ErrNotExist) {
 		return -fuse.ENOENT
 	}
-	switch err {
-	case os.ErrExist:
+	if errors.Is(err, os.ErrExist) {
 		return -fuse.EEXIST
-	case arvados.ErrInvalidArgument:
+	}
+	if errors.Is(err, arvados.ErrInvalidArgument) {
 		return -fuse.EINVAL
-	case arvados.ErrInvalidOperation:
+	}
+	if errors.Is(err, arvados.ErrInvalidOperation) {
 		return -fuse.ENOSYS
-	case arvados.ErrDirectoryNotEmpty:
+	}
+	if errors.Is(err, arvados.ErrDirectoryNotEmpty) {
 		return -fuse.ENOTEMPTY
-	case nil:
-		return 0
-	default:
-		return -fuse.EIO
 	}
+	return -fuse.EIO
 }
 
 func (fs *keepFS) Mkdir(path string, mode uint32) int {
@@ -252,11 +255,18 @@ func (fs *keepFS) Chmod(path string, mode uint32) (errc int) {
 	}
 	if fi, err := fs.root.Stat(path); err != nil {
 		return fs.errCode(err)
-	} else if mode & ^uint32(fuse.S_IFREG|fuse.S_IFDIR|0777) != 0 || (fi.Mode()&os.ModeDir != 0) != (mode&fuse.S_IFDIR != 0) {
+	} else if mode & ^uint32(fuse.S_IFREG|fuse.S_IFDIR|0777) != 0 {
+		// Refuse to set mode bits other than
+		// regfile/dir/perms
+		return -fuse.ENOSYS
+	} else if (fi.Mode()&os.ModeDir != 0) != (mode&fuse.S_IFDIR != 0) {
+		// Refuse to transform a regular file to a dir, or
+		// vice versa
 		return -fuse.ENOSYS
-	} else {
-		return 0
 	}
+	// As long as the change isn't nonsense, chmod is a no-op,
+	// because we don't save permission bits.
+	return 0
 }
 
 func (fs *keepFS) fillStat(stat *fuse.Stat_t, fi os.FileInfo) {
@@ -320,6 +330,16 @@ func (fs *keepFS) Read(path string, buf []byte, ofst int64, fh uint64) (n int) {
 		return fs.errCode(err)
 	}
 	n, err := f.Read(buf)
+	for err == nil && n < len(buf) {
+		// f is an io.Reader ("If some data is available but
+		// not len(p) bytes, Read conventionally returns what
+		// is available instead of waiting for more") -- but
+		// our caller requires us to either fill buf or reach
+		// EOF.
+		done := n
+		n, err = f.Read(buf[done:])
+		n += done
+	}
 	if err != nil && err != io.EOF {
 		log.Printf("error reading %q: %s", path, err)
 		return fs.errCode(err)