From 8cd2908846d11af9b33246171f71a923d35eb3c4 Mon Sep 17 00:00:00 2001 From: Boris Burkov Date: Wed, 18 Nov 2020 15:06:20 -0800 Subject: btrfs: clear oneshot options on mount and remount Some options only apply during mount time and are cleared at the end of mount. For now, the example is USEBACKUPROOT, but CLEAR_CACHE also fits the bill, and this is a preparation patch for also clearing that option. One subtlety is that the current code only resets USEBACKUPROOT on rw mounts, but the option is meaningfully "consumed" by a ro mount, so it feels appropriate to clear in that case as well. A subsequent read-write remount would not go through open_ctree, which is the only place that checks the option, so the change should be benign. Reviewed-by: Josef Bacik Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/disk-io.c | 14 +++++++++++++- fs/btrfs/disk-io.h | 1 + fs/btrfs/super.c | 1 + 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a3e0065bf635..292ea49f5ae3 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2870,6 +2870,16 @@ static int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info) return 0; } +/* + * Some options only have meaning at mount time and shouldn't persist across + * remounts, or be displayed. Clear these at the end of mount and remount + * code paths. + */ +void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info) +{ + btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT); +} + /* * Mounting logic specific to read-write file systems. Shared by open_ctree * and btrfs_remount when remounting from read-only to read-write. @@ -3359,7 +3369,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device } if (sb_rdonly(sb)) - return 0; + goto clear_oneshot; if (btrfs_test_opt(fs_info, CLEAR_CACHE) && btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) { @@ -3402,6 +3412,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device } set_bit(BTRFS_FS_OPEN, &fs_info->flags); +clear_oneshot: + btrfs_clear_oneshot_options(fs_info); return 0; fail_qgroup: diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index b509d1a490e7..7b3ecad88d7e 100644 --- a/fs/btrfs/disk-io.h +++ b/fs/btrfs/disk-io.h @@ -50,6 +50,7 @@ struct extent_buffer *btrfs_find_create_tree_block( u64 bytenr, u64 owner_root, int level); void btrfs_clean_tree_block(struct extent_buffer *buf); +void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info); int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info); int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_devices, diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 49b4a16488c9..93514555453b 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1999,6 +1999,7 @@ out: wake_up_process(fs_info->transaction_kthread); btrfs_remount_cleanup(fs_info, old_opts); + btrfs_clear_oneshot_options(fs_info); clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state); return 0; -- cgit v1.2.3