[PATCH V2 04/10] Btrfs: add a comment for fs_info->max_inline

[Miao Xie <miaox@cn.fujitsu.com>]

Though ->max_inline is a 64bit variant, and may be accessed by
multi-task, but it is just suggestive number, so we needn't add
anything to protect fs_info->max_inline, just add a comment to
explain wny we don't use a lock to protect it.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
Changelog v1 -> v2:
- modify the changelog and make it more clear.
---
 fs/btrfs/ctree.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 745e7ad..3e672916 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1288,6 +1288,12 @@ struct btrfs_fs_info {
 	atomic64_t last_trans_log_full_commit;
 	unsigned long mount_opt;
 	unsigned long compress_type:4;
+	/*
+	 * It is a suggestive number, the read side is safe even it gets a
+	 * wrong number because we will write out the data into a regular
+	 * extent. The write side(mount/remount) is under ->s_umount lock,
+	 * so it is also safe.
+	 */
 	u64 max_inline;
 	u64 alloc_start;
 	struct btrfs_transaction *running_transaction;
-- 
1.7.11.7