[RFC v2 3/6] fs: add a helper for thaw_super_locked() which does not unlock

[Luis Chamberlain]

The thaw_super_locked() expects the caller to hold the sb->s_umount
semaphore. It also handles the unlocking of the semaphore for you.
Allow for cases where the caller will do the unlocking of the semaphore.

Signed-off-by: Luis Chamberlain <mcg...@kernel.org>
---
 fs/super.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/fs/super.c b/fs/super.c
index 72b445a69a45..744b2399a272 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1730,14 +1730,13 @@ int freeze_super(struct super_block *sb)
 }
 EXPORT_SYMBOL(freeze_super);
 
-static int thaw_super_locked(struct super_block *sb)
+/* Caller deals with the sb->s_umount */
+static int __thaw_super_locked(struct super_block *sb)
 {
        int error;
 
-       if (!sb_is_frozen(sb)) {
-               up_write(&sb->s_umount);
+       if (!sb_is_frozen(sb))
                return -EINVAL;
-       }
 
        if (sb_rdonly(sb)) {
                sb->s_writers.frozen = SB_UNFROZEN;
@@ -1752,7 +1751,6 @@ static int thaw_super_locked(struct super_block *sb)
                        printk(KERN_ERR
                                "VFS:Filesystem thaw failed\n");
                        lockdep_sb_freeze_release(sb);
-                       up_write(&sb->s_umount);
                        return error;
                }
        }
@@ -1761,10 +1759,25 @@ static int thaw_super_locked(struct super_block *sb)
        sb_freeze_unlock(sb);
 out:
        wake_up(&sb->s_writers.wait_unfrozen);
-       deactivate_locked_super(sb);
        return 0;
 }
 
+/* Handles unlocking of sb->s_umount for you */
+static int thaw_super_locked(struct super_block *sb)
+{
+       int error;
+
+       error = __thaw_super_locked(sb);
+       if (error) {
+               up_write(&sb->s_umount);
+               return error;
+       }
+
+       deactivate_locked_super(sb);
+
+       return 0;
+ }
+
 /**
  * thaw_super -- unlock filesystem
  * @sb: the super to thaw
-- 
2.29.2