linux-ext4 - [PATCH 4/7] fuse2fs: implement dirsync mode

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Message-ID: <174786678471.1385038.12860188625256645865.stgit@frogsfrogsfrogs>
Date: Wed, 21 May 2025 15:44:20 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org
Subject: [PATCH 4/7] fuse2fs: implement dirsync mode

From: Darrick J. Wong <djwong@...nel.org>

Implement dirsync so that we only perform full metadata flushes on
directory updates when the sysadmin explicitly wants it.

Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 misc/fuse2fs.c |   36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)


diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index fc338058835360..6fae10e9473ea5 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -162,6 +162,7 @@ struct fuse2fs {
 	uint8_t kernel;
 	uint8_t directio;
 	uint8_t acl;
+	uint8_t dirsync;
 
 	int blocklog;
 	unsigned int blockmask;
@@ -1471,6 +1472,13 @@ static int __op_unlink(struct fuse2fs *ff, const char *path)
 	ret = remove_inode(ff, ino);
 	if (ret)
 		goto out;
+
+	/* Flush the whole mess out */
+	if (ff->dirsync) {
+		err = ext2fs_flush2(fs, 0);
+		if (err)
+			ret = translate_error(fs, 0, err);
+	}
 out:
 	return ret;
 }
@@ -1591,6 +1599,13 @@ static int __op_rmdir(struct fuse2fs *ff, const char *path)
 		}
 	}
 
+	/* Flush the whole mess out */
+	if (ff->dirsync) {
+		err = ext2fs_flush2(fs, 0);
+		if (err)
+			ret = translate_error(fs, 0, err);
+	}
+
 out:
 	return ret;
 }
@@ -1963,9 +1978,11 @@ static int op_rename(const char *from, const char *to
 		goto out2;
 
 	/* Flush the whole mess out */
-	err = ext2fs_flush2(fs, 0);
-	if (err)
-		ret = translate_error(fs, 0, err);
+	if (ff->dirsync) {
+		err = ext2fs_flush2(fs, 0);
+		if (err)
+			ret = translate_error(fs, 0, err);
+	}
 
 out2:
 	free(temp_from);
@@ -2072,6 +2089,13 @@ static int op_link(const char *src, const char *dest)
 	if (ret)
 		goto out2;
 
+	/* Flush the whole mess out */
+	if (ff->dirsync) {
+		err = ext2fs_flush2(fs, 0);
+		if (err)
+			ret = translate_error(fs, 0, err);
+	}
+
 out2:
 	pthread_mutex_unlock(&ff->bfl);
 out:
@@ -4256,6 +4280,7 @@ enum {
 	FUSE2FS_HELP,
 	FUSE2FS_HELPFULL,
 	FUSE2FS_CACHE_SIZE,
+	FUSE2FS_DIRSYNC,
 };
 
 #define FUSE2FS_OPT(t, p, v) { t, offsetof(struct fuse2fs, p), v }
@@ -4281,6 +4306,7 @@ static struct fuse_opt fuse2fs_opts[] = {
 	FUSE_OPT_KEY("noblock_validity", FUSE2FS_IGNORED),
 	FUSE_OPT_KEY("nodelalloc",	FUSE2FS_IGNORED),
 	FUSE_OPT_KEY("cache_size=%s",	FUSE2FS_CACHE_SIZE),
+	FUSE_OPT_KEY("dirsync",		FUSE2FS_DIRSYNC),
 
 	FUSE_OPT_KEY("-V",             FUSE2FS_VERSION),
 	FUSE_OPT_KEY("--version",      FUSE2FS_VERSION),
@@ -4297,6 +4323,10 @@ static int fuse2fs_opt_proc(void *data, const char *arg,
 	struct fuse2fs *ff = data;
 
 	switch (key) {
+	case FUSE2FS_DIRSYNC:
+		ff->dirsync = 1;
+		/* pass through to libfuse */
+		return 1;
 	case FUSE_OPT_KEY_NONOPT:
 		if (!ff->device) {
 			ff->device = strdup(arg);