f2fs: checkpoint disabling

Note that, it requires "f2fs: return correct errno in f2fs_gc".

This adds a lightweight non-persistent snapshotting scheme to f2fs.

To use, mount with the option checkpoint=disable, and to return to
normal operation, remount with checkpoint=enable. If the filesystem
is shut down before remounting with checkpoint=enable, it will revert
back to its apparent state when it was first mounted with
checkpoint=disable. This is useful for situations where you wish to be
able to roll back the state of the disk in case of some critical
failure.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
[Jaegeuk Kim: use SB_RDONLY instead of MS_RDONLY]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index 75bc62edc4c1..026e10f30889 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -272,7 +272,8 @@ static int stat_show(struct seq_file *s, void *v)
                 seq_printf(s, "\n=====[ partition info(%pg). #%d, %s, CP: %s]=====\n",
                         si->sbi->sb->s_bdev, i++,
                         f2fs_readonly(si->sbi->sb) ? "RO": "RW",
-                        f2fs_cp_error(si->sbi) ? "Error": "Good");
+                        is_set_ckpt_flags(si->sbi, CP_DISABLED_FLAG) ?
+                        "Disabled": (f2fs_cp_error(si->sbi) ? "Error": "Good"));
                 seq_printf(s, "[SB: 1] [CP: 2] [SIT: %d] [NAT: %d] ",
                            si->sit_area_segs, si->nat_area_segs);
                 seq_printf(s, "[SSA: %d] [MAIN: %d",