Btrfs: add a comment for fs_info->max_inline

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>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 6932101..169baa8 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1297,6 +1297,12 @@ struct btrfs_fs_info {
        u64 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;