-clear out log tree
-
-*btrfs rescue zero-log* will remove the log tree if log tree is corrupt, which
-will allow you to mount the filesystem again.
-
-The common case where this happens has been fixed a long time ago,
-so it is unlikely that you will see this particular problem.
-
-One can determine whether *btrfs-zero-log* is needed according to the kernel
+clear the filesystem log tree
++
+This command will clear the filesystem log tree. This may fix a specific
+set of problem when the filesystem mount fails due to the log replay. See below
+for sample stacktraces that may show up in system log.
++
+The common case where this happens was fixed a long time ago,
+so it is unlikely that you will see this particular problem, but the command is
+kept around.
++
+NOTE: clearing the log may lead to loss of changes that were made since the
+last transaction commit. This may be up to 30 seconds (default commit period)
+or less if the commit was implied by other filesystem activity.
++
+One can determine whether *zero-log* is needed according to the kernel