[PATCH v9 02/17] fs: add generic FS_IOC_SHUTDOWN definitions

Namjae Jeon
2026-02-13T08:20:55Z

Currently, several filesystems (e.g., xfs, ext4, btrfs) implement
a "shutdown" or "going down" ioctl to simulate filesystem force a shutdown.
While they often use the same underlying numeric value, the definition is
duplicated across filesystem headers or private definitions.

Add generic definitions for FS_IOC_SHUTDOWN in uapi/linux/fs.h.
This allows new filesystems (like ntfs) to implement this feature using
a standard VFS definition and paves the way for existing filesystems
to unify their definitions later.

The flag names are standardized as FS_SHUTDOWN_* to be consistent with
the ioctl name, replacing the historical GOING_DOWN naming convention.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
include/uapi/linux/fs.h | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 66ca526cf786..32e24778c9e5 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -656,4 +656,16 @@ struct procmap_query {
__u64 build_id_addr; /* in */
};

+/*
+ * Shutdown the filesystem.
+ */
+#define FS_IOC_SHUTDOWN _IOR('X', 125, __u32)
+
+/*
+ * Flags for FS_IOC_SHUTDOWN
+ */
+#define FS_SHUTDOWN_FLAGS_DEFAULT 0x0
+#define FS_SHUTDOWN_FLAGS_LOGFLUSH 0x1 /* flush log but not data*/
+#define FS_SHUTDOWN_FLAGS_NOLOGFLUSH 0x2 /* don't flush log nor data */
+
#endif /* _UAPI_LINUX_FS_H */
--
2.25.1