When the test function is not defined in sget_fc(), we always need
to allocate a new superblock. So there is no point in acquiring the
sb_lock twice in this case. Optimize the !test case by pre-allocating
the superblock first before acquring the lock.
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
fs/super.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/super.c b/fs/super.c
index a6405d44d4ca..6601267f6fe0 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -520,6 +520,8 @@ struct super_block *sget_fc(struct fs_context *fc,
struct user_namespace *user_ns = fc->global ? &init_user_ns : fc->user_ns;
int err;
+ if (!test)
+ goto prealloc;
retry:
spin_lock(&sb_lock);
if (test) {
@@ -530,6 +532,7 @@ struct super_block *sget_fc(struct fs_context *fc,
}
if (!s) {
spin_unlock(&sb_lock);
+prealloc:
s = alloc_super(fc->fs_type, fc->sb_flags, user_ns);
if (!s)
return ERR_PTR(-ENOMEM);
--
2.27.0
