[PATCH 2/6] f2fs: support goingdown for fs shutdown

[Jaegeuk Kim <jaegeuk@kernel.org>]

This patch add an ioctl to shutdown f2fs, which stops all the further block
writes after this point.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h |  1 +
 fs/f2fs/file.c | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ba30218..febad35 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -209,6 +209,7 @@ static inline bool __has_cursum_space(struct f2fs_summary_block *sum, int size,
 #define F2FS_IOC_START_VOLATILE_WRITE	_IO(F2FS_IOCTL_MAGIC, 3)
 #define F2FS_IOC_RELEASE_VOLATILE_WRITE	_IO(F2FS_IOCTL_MAGIC, 4)
 #define F2FS_IOC_ABORT_VOLATILE_WRITE	_IO(F2FS_IOCTL_MAGIC, 5)
+#define F2FS_IOC_GOINGDOWN		_IO(F2FS_IOCTL_MAGIC, 6)
 
 #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
 /*
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 5df3367..de2f669 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1020,6 +1020,18 @@ static int f2fs_ioc_abort_volatile_write(struct file *filp)
 	return ret;
 }
 
+static int f2fs_ioc_goingdown(struct file *filp)
+{
+	struct inode *inode = file_inode(filp);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	f2fs_stop_checkpoint(sbi);
+	return 0;
+}
+
 static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
@@ -1067,6 +1079,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return f2fs_ioc_release_volatile_write(filp);
 	case F2FS_IOC_ABORT_VOLATILE_WRITE:
 		return f2fs_ioc_abort_volatile_write(filp);
+	case F2FS_IOC_GOINGDOWN:
+		return f2fs_ioc_goingdown(filp);
 	case FITRIM:
 		return f2fs_ioc_fitrim(filp, arg);
 	default:
-- 
2.1.1