diff mbox series

[v7,05/12] btrfs: clear oneshot options on mount and remount

Message ID 9c564def626db6d0de5ce0fc336aad4475050821.1605736355.git.boris@bur.io (mailing list archive)
State New, archived
Headers show
Series btrfs: free space tree mounting fixes | expand

Commit Message

Boris Burkov Nov. 18, 2020, 11:06 p.m. UTC
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

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.

Signed-off-by: Boris Burkov <boris@bur.io>
 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 mbox series


diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d934eb80ff49..0bc7d9766f8c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2884,6 +2884,16 @@  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.
@@ -3365,7 +3375,7 @@  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)) {
@@ -3409,6 +3419,8 @@  int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	set_bit(BTRFS_FS_OPEN, &fs_info->flags);
+	btrfs_clear_oneshot_options(fs_info);
 	return 0;
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 945914d1747f..3bb097f22314 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_mount_rw(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 ad5a78970389..cca00cc0c98c 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1992,6 +1992,7 @@  static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 	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;