From 211f828987934b8799d7971a731cd971f5eaa2dd Mon Sep 17 00:00:00 2001
From: Sandy Xu <sandy@juicedata.io>
Date: Wed, 24 Apr 2024 15:56:43 +0800
Subject: [PATCH 1/2] cmd/dump: use a temp file during dumping

---
 cmd/dump.go | 43 +++++++++++++++++++++++++++++--------------
 1 file changed, 29 insertions(+), 14 deletions(-)

diff --git a/cmd/dump.go b/cmd/dump.go
index 2b810cb189ba..63dfcfac6af6 100644
--- a/cmd/dump.go
+++ b/cmd/dump.go
@@ -72,25 +72,26 @@ Details: https://juicefs.com/docs/community/metadata_dump_load`,
 	}
 }
 
-func dump(ctx *cli.Context) (err error) {
-	setup(ctx, 1)
-	metaUri := ctx.Args().Get(0)
-	dst := ctx.Args().Get(1)
-	removePassword(metaUri)
+func dumpMeta(m meta.Meta, dst string, threads int, keepSecret, fast, skipTrash bool) (err error) {
 	var w io.WriteCloser
-	if ctx.Args().Len() == 1 {
+	if dst == "" {
 		w = os.Stdout
-		dst = "STDOUT"
 	} else {
-		fp, err := os.OpenFile(dst, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
-		if err != nil {
-			return err
+		tmp := dst + ".tmp"
+		fp, e := os.OpenFile(tmp, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
+		if e != nil {
+			return e
 		}
 		defer func() {
 			e := fp.Close()
 			if err == nil {
 				err = e
 			}
+			if err == nil {
+				err = os.Rename(tmp, dst)
+			} else {
+				_ = os.Remove(tmp)
+			}
 		}()
 		if strings.HasSuffix(dst, ".gz") {
 			zw := gzip.NewWriter(fp)
@@ -105,6 +106,17 @@ func dump(ctx *cli.Context) (err error) {
 			w = fp
 		}
 	}
+	return m.DumpMeta(w, 1, threads, keepSecret, fast, skipTrash)
+}
+
+func dump(ctx *cli.Context) error {
+	setup(ctx, 1)
+	metaUri := ctx.Args().Get(0)
+	var dst string
+	if ctx.Args().Len() > 1 {
+		dst = ctx.Args().Get(1)
+	}
+	removePassword(metaUri)
 	metaConf := meta.DefaultConf()
 	metaConf.Subdir = ctx.String("subdir")
 	m := meta.NewClient(metaUri, metaConf)
@@ -119,9 +131,12 @@ func dump(ctx *cli.Context) (err error) {
 		logger.Warnf("Invalid threads number %d, reset to 1", threads)
 		threads = 1
 	}
-	if err := m.DumpMeta(w, 1, threads, ctx.Bool("keep-secret-key"), ctx.Bool("fast"), ctx.Bool("skip-trash")); err != nil {
-		return err
+	err := dumpMeta(m, dst, threads, ctx.Bool("keep-secret-key"), ctx.Bool("fast"), ctx.Bool("skip-trash"))
+	if err == nil {
+		if dst == "" {
+			dst = "STDOUT"
+		}
+		logger.Infof("Dump metadata into %s succeed", dst)
 	}
-	logger.Infof("Dump metadata into %s succeed", dst)
-	return nil
+	return err
 }

From c2144331ec390b74fd5819cb3d66d862a03e562a Mon Sep 17 00:00:00 2001
From: Sandy Xu <sandy@juicedata.io>
Date: Wed, 24 Apr 2024 16:03:32 +0800
Subject: [PATCH 2/2] fix

---
 cmd/dump.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cmd/dump.go b/cmd/dump.go
index 63dfcfac6af6..4518b03ea6a5 100644
--- a/cmd/dump.go
+++ b/cmd/dump.go
@@ -93,6 +93,7 @@ func dumpMeta(m meta.Meta, dst string, threads int, keepSecret, fast, skipTrash
 				_ = os.Remove(tmp)
 			}
 		}()
+
 		if strings.HasSuffix(dst, ".gz") {
 			zw := gzip.NewWriter(fp)
 			defer func() {
@@ -117,6 +118,7 @@ func dump(ctx *cli.Context) error {
 		dst = ctx.Args().Get(1)
 	}
 	removePassword(metaUri)
+
 	metaConf := meta.DefaultConf()
 	metaConf.Subdir = ctx.String("subdir")
 	m := meta.NewClient(metaUri, metaConf)
@@ -126,6 +128,7 @@ func dump(ctx *cli.Context) error {
 	if st := m.Chroot(meta.Background, metaConf.Subdir); st != 0 {
 		return st
 	}
+
 	threads := ctx.Int("threads")
 	if threads <= 0 {
 		logger.Warnf("Invalid threads number %d, reset to 1", threads)