No need to do lock_super() for exclusion in generic_shutdown_super()
We can't run into contention on it. All other callers of lock_super()
either hold s_umount (and we have it exclusive) or hold an active
reference to superblock in question, which prevents the call of
generic_shutdown_super() while the reference is held. So we can
replace lock_super(s) with get_fs_excl() in generic_shutdown_super()
(and corresponding change for unlock_super(), of course).
Since ext4 expects s_lock held for its put_super, take lock_super()
into it. The rest of filesystems do not care at all.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c7b8f8d..0d3034c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -576,6 +576,7 @@
struct ext4_super_block *es = sbi->s_es;
int i, err;
+ lock_super(sb);
if (sb->s_dirt)
ext4_write_super(sb);
@@ -645,7 +646,6 @@
unlock_super(sb);
kobject_put(&sbi->s_kobj);
wait_for_completion(&sbi->s_kobj_unregister);
- lock_super(sb);
lock_kernel();
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
diff --git a/fs/super.c b/fs/super.c
index 49f670c..54fd331 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -304,7 +304,7 @@
if (sb->s_root) {
shrink_dcache_for_umount(sb);
sync_filesystem(sb);
- lock_super(sb);
+ get_fs_excl();
sb->s_flags &= ~MS_ACTIVE;
/* bad name - it should be evict_inodes() */
@@ -322,7 +322,7 @@
}
unlock_kernel();
- unlock_super(sb);
+ put_fs_excl();
}
spin_lock(&sb_lock);
/* should be initialized for __put_super_and_need_restart() */