Move the "fool the lockdep" code from sb_wait_write() into the new
simple helper, sb_lockdep_release(), called once before return from
freeze_super().
This is preparation, but imo this makes sense in any case. This way
we do not hide from lockdep the "write" locks we hold when we call
s_op->freeze_fs(sb).
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
fs/super.c | 16 ++++++++++------
1 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/fs/super.c b/fs/super.c
index d0fdd49..e7ea9f1 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1236,16 +1236,10 @@ static void sb_wait_write(struct super_block *sb, int
level)
{
s64 writers;
- /*
- * We just cycle-through lockdep here so that it does not complain
- * about returning with lock to userspace
- */
rwsem_acquire(&sb->s_writers.lock_map[level-1], 0, 0, _THIS_IP_);
- rwsem_release(&sb->s_writers.lock_map[level-1], 1, _THIS_IP_);
do {
DEFINE_WAIT(wait);
-
/*
* We use a barrier in prepare_to_wait() to separate setting
* of frozen and checking of the counter
@@ -1261,6 +1255,14 @@ static void sb_wait_write(struct super_block *sb, int
level)
} while (writers);
}
+static void sb_freeze_release(struct super_block *sb)
+{
+ int level;
+ /* Avoid the warning from lockdep_sys_exit() */
+ for (level = 0; level < SB_FREEZE_LEVELS; ++level)
+ rwsem_release(sb->s_writers.lock_map + level, 1, _THIS_IP_);
+}
+
/**
* freeze_super - lock the filesystem and force it into a consistent state
* @sb: the super to lock
@@ -1349,6 +1351,7 @@ int freeze_super(struct super_block *sb)
sb->s_writers.frozen = SB_UNFROZEN;
smp_wmb();
wake_up(&sb->s_writers.wait_unfrozen);
+ sb_freeze_release(sb);
deactivate_locked_super(sb);
return ret;
}
@@ -1358,6 +1361,7 @@ int freeze_super(struct super_block *sb)
* sees write activity when frozen is set to SB_FREEZE_COMPLETE.
*/
sb->s_writers.frozen = SB_FREEZE_COMPLETE;
+ sb_freeze_release(sb);
up_write(&sb->s_umount);
return 0;
}
--
1.5.5.1
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