From d275dbd1832bcfad6338dd14d16d619fd016b94a Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 13 May 2015 16:41:51 +0200 Subject: [PATCH] btrfs-progs: Introduce change_fsid_prepare and change_fsid_done functions These two functions will write flags to all supers before and after fsid/chunk tree id change, informing kernel not to mount a inconsistent fs. Signed-off-by: Qu Wenruo [removed chunk tree super flag] Signed-off-by: David Sterba --- btrfstune.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/btrfstune.c b/btrfstune.c index 77a8b7ac..9a63f41b 100644 --- a/btrfstune.c +++ b/btrfstune.c @@ -262,6 +262,34 @@ out: return ret; } +static int change_fsid_prepare(struct btrfs_fs_info *fs_info) +{ + u64 flags = btrfs_super_flags(fs_info->super_copy); + + if (!fs_info->new_fsid && !fs_info->new_chunk_tree_uuid) + return 0; + + if (fs_info->new_fsid) + flags |= BTRFS_SUPER_FLAG_CHANGING_FSID; + btrfs_set_super_flags(fs_info->super_copy, flags); + + return write_all_supers(fs_info->tree_root); +} + +static int change_fsid_done(struct btrfs_fs_info *fs_info) +{ + u64 flags = btrfs_super_flags(fs_info->super_copy); + + if (!fs_info->new_fsid && !fs_info->new_chunk_tree_uuid) + return 0; + + if (fs_info->new_fsid) + flags &= ~BTRFS_SUPER_FLAG_CHANGING_FSID; + btrfs_set_super_flags(fs_info->super_copy, flags); + + return write_all_supers(fs_info->tree_root); +} + static void print_usage(void) { fprintf(stderr, "usage: btrfstune [options] device\n");