[PATCH 4/4] libfuse: add syncfs support to the upper library

Darrick J. Wong
2025-09-16T00:47:47Z

Support syncfs in the upper level library.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
include/fuse.h | 5 +++++
lib/fuse.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+)

diff --git a/include/fuse.h b/include/fuse.h
index e53e92786cea08..0b81a1259c4f09 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -903,6 +903,11 @@ struct fuse_operations {
*/
int (*iomap_config) (uint64_t supported_flags, off_t maxbytes,
struct fuse_iomap_config *cfg);
+
+ /**
+ * Flush the entire filesystem to disk.
+ */
+ int (*syncfs) (const char *path);
};

/** Extra context that may be needed by some filesystems
diff --git a/lib/fuse.c b/lib/fuse.c
index 1c813ec5a697a0..ac0206f6ed4544 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -2963,6 +2963,16 @@ static int fuse_fs_iomap_config(struct fuse_fs *fs, uint64_t flags,
return fs->op.iomap_config(flags, maxbytes, cfg);
}

+static int fuse_fs_syncfs(struct fuse_fs *fs, const char *path)
+{
+ fuse_get_context()->private_data = fs->user_data;
+ if (!fs->op.syncfs)
+ return -ENOSYS;
+ if (fs->debug)
+ fuse_log(FUSE_LOG_DEBUG, "syncfs[%s]\n", path);
+ return fs->op.syncfs(path);
+}
+
static void fuse_lib_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
int valid, struct fuse_file_info *fi)
{
@@ -4836,6 +4846,26 @@ static void fuse_lib_iomap_config(fuse_req_t req, uint64_t flags,
fuse_reply_iomap_config(req, &cfg);
}

+static void fuse_lib_syncfs(fuse_req_t req, fuse_ino_t ino)
+{
+ struct fuse *f = req_fuse_prepare(req);
+ struct fuse_intr_data d;
+ char *path;
+ int err;
+
+ err = get_path(f, ino, &path);
+ if (err) {
+ reply_err(req, err);
+ return;
+ }
+
+ fuse_prepare_interrupt(f, req, &d);
+ err = fuse_fs_syncfs(f->fs, path);
+ fuse_finish_interrupt(f, req, &d);
+ free_path(f, ino, path);
+ reply_err(req, err);
+}
+
static int clean_delay(struct fuse *f)
{
/*
@@ -4937,6 +4967,7 @@ static struct fuse_lowlevel_ops fuse_path_ops = {
#ifdef HAVE_STATX
.statx = fuse_lib_statx,
#endif
+ .syncfs = fuse_lib_syncfs,
.iomap_begin = fuse_lib_iomap_begin,
.iomap_end = fuse_lib_iomap_end,
.iomap_ioend = fuse_lib_iomap_ioend,