[PATCH 08/19] pstore: shrink the pstore_sb_lock critical section in pstore_kill_sb

[Christoph Hellwig]

->kill_sb can't race with creating ->fill_super because pstore is a
_single file system that only ever has a single sb instance, and we wait
for the previous one to go away before creating a new one.  Reduce
the critical section so that is is not held over generic_shutdown_super.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 fs/pstore/inode.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 585360706b335f..fd1d24b47160d0 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -467,10 +467,9 @@ static struct dentry *pstore_mount(struct file_system_type *fs_type,
 
 static void pstore_kill_sb(struct super_block *sb)
 {
-	mutex_lock(&pstore_sb_lock);
-	WARN_ON(pstore_sb && pstore_sb != sb);
-
 	kill_litter_super(sb);
+
+	mutex_lock(&pstore_sb_lock);
 	pstore_sb = NULL;
 
 	mutex_lock(&records_list_lock);
-- 
2.39.2