os/FileStore: fix mount/remount force_sync race

Consider:

 - mount
 - sync_entry is doing some work
 - umount
   - set force_sync = true
   - set done = true
 - sync_entry exits (due to done)
   - ..but does not set force_sync = false
 - mount
 - journal replay starts
 - sync_entry sees force_sync and does a commit while op_seq == 0
 ...crash...

Fixes: #9144
Backport: firefly, dumpling
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit dd11042f969b94f7a461d02e1475794031c79f61)

Conflicts:
	src/os/FileStore.cc

diff --git a/src/os/FileStore.cc b/src/os/FileStore.cc
index d462be13e1883da62af07c9bba874090ffca9080..a11e0777a97c1a81a0bb3239cb323cf90cc50f3a 100644 (file)
--- a/src/os/FileStore.cc
+++ b/src/os/FileStore.cc
@@ -1961,6 +1961,9 @@ int FileStore::umount()
     TEMP_FAILURE_RETRY(::close(basedir_fd));
     basedir_fd = -1;
   }
+
+  force_sync = false;
+
   object_map.reset();
 
   {