[PATCH 19/19] fuse2fs: implement freeze and shutdown requests

Darrick J. Wong
2026-04-29T14:57:35Z

Handle freezing and shutting down the filesystem if requested.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
fuse4fs/fuse4fs.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++
misc/fuse2fs.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 175 insertions(+)

diff --git a/fuse4fs/fuse4fs.c b/fuse4fs/fuse4fs.c
index 6ea2d30772ae5a..46f81e2066b044 100644
--- a/fuse4fs/fuse4fs.c
+++ b/fuse4fs/fuse4fs.c
@@ -240,6 +240,7 @@ struct fuse4fs_file_handle {

enum fuse4fs_opstate {
F4OP_READONLY,
+ F4OP_WRITABLE_FROZEN,
F4OP_WRITABLE,
F4OP_SHUTDOWN,
};
@@ -6388,6 +6389,91 @@ static void op_fallocate(fuse_req_t req, fuse_ino_t fino EXT2FS_ATTR((unused)),
}
#endif /* SUPPORT_FALLOCATE */

+#if FUSE_VERSION >= FUSE_MAKE_VERSION(3, 99)
+static void op_freezefs(fuse_req_t req, fuse_ino_t ino, uint64_t unlinked)
+{
+ struct fuse4fs *ff = fuse4fs_get(req);
+ ext2_filsys fs;
+ errcode_t err;
+ int ret = 0;
+
+ FUSE4FS_CHECK_CONTEXT(req);
+ fs = fuse4fs_start(ff);
+
+ if (ff->opstate == F4OP_WRITABLE) {
+ if (fs->super->s_error_count)
+ fs->super->s_state |= EXT2_ERROR_FS;
+ else if (!unlinked)
+ fs->super->s_state |= EXT2_VALID_FS;
+ ext2fs_mark_super_dirty(fs);
+ err = ext2fs_set_gdt_csum(fs);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ err = ext2fs_flush2(fs, 0);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ ff->opstate = F4OP_WRITABLE_FROZEN;
+ }
+
+out_unlock:
+ fs->super->s_state &= ~EXT2_VALID_FS;
+ fuse4fs_finish(ff, ret);
+ fuse_reply_err(req, -ret);
+}
+
+static void op_unfreezefs(fuse_req_t req, fuse_ino_t ino)
+{
+ struct fuse4fs *ff = fuse4fs_get(req);
+ ext2_filsys fs;
+ errcode_t err;
+ int ret = 0;
+
+ FUSE4FS_CHECK_CONTEXT(req);
+ fs = fuse4fs_start(ff);
+
+ if (ff->opstate == F4OP_WRITABLE_FROZEN) {
+ if (fs->super->s_error_count)
+ fs->super->s_state |= EXT2_ERROR_FS;
+ fs->super->s_state &= ~EXT2_VALID_FS;
+ ext2fs_mark_super_dirty(fs);
+ err = ext2fs_set_gdt_csum(fs);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ err = ext2fs_flush2(fs, 0);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ ff->opstate = F4OP_WRITABLE;
+ }
+
+out_unlock:
+ fuse4fs_finish(ff, ret);
+ fuse_reply_err(req, -ret);
+}
+
+static void op_shutdownfs(fuse_req_t req, fuse_ino_t ino, uint64_t flags)
+{
+ const struct fuse_ctx *ctxt = fuse_req_ctx(req);
+ struct fuse4fs *ff = fuse4fs_get(req);
+ int ret;
+
+ ret = ioctl_shutdown(ff, ctxt, NULL, NULL, 0);
+
+ fuse_reply_err(req, -ret);
+}
+#endif
+
#ifdef HAVE_FUSE_IOMAP
static void fuse4fs_iomap_hole(struct fuse4fs *ff, struct fuse_file_iomap *iomap,
off_t pos, uint64_t count)
@@ -7685,6 +7771,11 @@ static struct fuse_lowlevel_ops fs_ops = {
#if FUSE_VERSION >= FUSE_MAKE_VERSION(3, 18)
.statx = op_statx,
#endif
+#if FUSE_VERSION >= FUSE_MAKE_VERSION(3, 99)
+ .freezefs = op_freezefs,
+ .unfreezefs = op_unfreezefs,
+ .shutdownfs = op_shutdownfs,
+#endif
#ifdef HAVE_FUSE_IOMAP
.iomap_begin = op_iomap_begin,
.iomap_end = op_iomap_end,
diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index fe45ffa86823b0..16b010fd28d4b5 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -223,6 +223,7 @@ struct fuse2fs_file_handle {

enum fuse2fs_opstate {
F2OP_READONLY,
+ F2OP_WRITABLE_FROZEN,
F2OP_WRITABLE,
F2OP_SHUTDOWN,
};
@@ -5709,6 +5710,86 @@ static int op_fallocate(const char *path EXT2FS_ATTR((unused)), int mode,
}
#endif /* SUPPORT_FALLOCATE */

+#if FUSE_VERSION >= FUSE_MAKE_VERSION(3, 99)
+static int op_freezefs(const char *path, uint64_t unlinked)
+{
+ struct fuse2fs *ff = fuse2fs_get();
+ ext2_filsys fs;
+ errcode_t err;
+ int ret = 0;
+
+ FUSE2FS_CHECK_CONTEXT(ff);
+ fs = fuse2fs_start(ff);
+
+ if (ff->opstate == F2OP_WRITABLE) {
+ if (fs->super->s_error_count)
+ fs->super->s_state |= EXT2_ERROR_FS;
+ else if (!unlinked)
+ fs->super->s_state |= EXT2_VALID_FS;
+ ext2fs_mark_super_dirty(fs);
+ err = ext2fs_set_gdt_csum(fs);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ err = ext2fs_flush2(fs, 0);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ ff->opstate = F2OP_WRITABLE_FROZEN;
+ }
+
+out_unlock:
+ fs->super->s_state &= ~EXT2_VALID_FS;
+ fuse2fs_finish(ff, ret);
+ return ret;
+}
+
+static int op_unfreezefs(const char *path)
+{
+ struct fuse2fs *ff = fuse2fs_get();
+ ext2_filsys fs;
+ errcode_t err;
+ int ret = 0;
+
+ FUSE2FS_CHECK_CONTEXT(ff);
+ fs = fuse2fs_start(ff);
+
+ if (ff->opstate == F2OP_WRITABLE_FROZEN) {
+ if (fs->super->s_error_count)
+ fs->super->s_state |= EXT2_ERROR_FS;
+ ext2fs_mark_super_dirty(fs);
+ err = ext2fs_set_gdt_csum(fs);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ err = ext2fs_flush2(fs, 0);
+ if (err) {
+ ret = translate_error(fs, 0, err);
+ goto out_unlock;
+ }
+
+ ff->opstate = F2OP_WRITABLE;
+ }
+
+out_unlock:
+ fuse2fs_finish(ff, ret);
+ return ret;
+}
+
+static int op_shutdownfs(const char *path, uint64_t flags)
+{
+ struct fuse2fs *ff = fuse2fs_get();
+
+ return ioctl_shutdown(ff, NULL, NULL);
+}
+#endif
+
#ifdef HAVE_FUSE_IOMAP
static void fuse2fs_iomap_hole(struct fuse2fs *ff, struct fuse_file_iomap *iomap,
off_t pos, uint64_t count)
@@ -6993,6 +7074,9 @@ static struct fuse_operations fs_ops = {
#endif
#if FUSE_VERSION >= FUSE_MAKE_VERSION(3, 99)
.getattr_iflags = op_getattr_iflags,
+ .freezefs = op_freezefs,
+ .unfreezefs = op_unfreezefs,
+ .shutdownfs = op_shutdownfs,
#endif
#ifdef HAVE_FUSE_IOMAP
.iomap_begin = op_iomap_begin,