1 files changed, 32 insertions, 2 deletions

diff --git a/fs/super.c b/fs/super.c
index e6db39aadaee..da68584815e4 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1644,6 +1644,24 @@ static void sb_freeze_unlock(struct super_block *sb, int level)
 		percpu_up_write(sb->s_writers.rw_sem + level);
 }
 
+static int wait_for_partially_frozen(struct super_block *sb)
+{
+	int ret = 0;
+
+	do {
+		unsigned short old = sb->s_writers.frozen;
+
+		up_write(&sb->s_umount);
+		ret = wait_var_event_killable(&sb->s_writers.frozen,
+					       sb->s_writers.frozen != old);
+		down_write(&sb->s_umount);
+	} while (ret == 0 &&
+		 sb->s_writers.frozen != SB_UNFROZEN &&
+		 sb->s_writers.frozen != SB_FREEZE_COMPLETE);
+
+	return ret;
+}
+
 /**
  * freeze_super - lock the filesystem and force it into a consistent state
  * @sb: the super to lock
@@ -1695,6 +1713,7 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 	atomic_inc(&sb->s_active);
 	down_write(&sb->s_umount);
 
+retry:
 	if (sb->s_writers.frozen == SB_FREEZE_COMPLETE) {
 		if (sb->s_writers.freeze_holders & who) {
 			deactivate_locked_super(sb);
@@ -1713,8 +1732,13 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 	}
 
 	if (sb->s_writers.frozen != SB_UNFROZEN) {
-		deactivate_locked_super(sb);
-		return -EBUSY;
+		ret = wait_for_partially_frozen(sb);
+		if (ret) {
+			deactivate_locked_super(sb);
+			return ret;
+		}
+
+		goto retry;
 	}
 
 	if (!(sb->s_flags & SB_BORN)) {
@@ -1726,6 +1750,7 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 		/* Nothing to do really... */
 		sb->s_writers.freeze_holders |= who;
 		sb->s_writers.frozen = SB_FREEZE_COMPLETE;
+		wake_up_var(&sb->s_writers.frozen);
 		up_write(&sb->s_umount);
 		return 0;
 	}
@@ -1745,6 +1770,7 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 	if (ret) {
 		sb->s_writers.frozen = SB_UNFROZEN;
 		sb_freeze_unlock(sb, SB_FREEZE_PAGEFAULT);
+		wake_up_var(&sb->s_writers.frozen);
 		deactivate_locked_super(sb);
 		return ret;
 	}
@@ -1760,6 +1786,7 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 				"VFS:Filesystem freeze failed\n");
 			sb->s_writers.frozen = SB_UNFROZEN;
 			sb_freeze_unlock(sb, SB_FREEZE_FS);
+			wake_up_var(&sb->s_writers.frozen);
 			deactivate_locked_super(sb);
 			return ret;
 		}
@@ -1770,6 +1797,7 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 	 */
 	sb->s_writers.freeze_holders |= who;
 	sb->s_writers.frozen = SB_FREEZE_COMPLETE;
+	wake_up_var(&sb->s_writers.frozen);
 	lockdep_sb_freeze_release(sb);
 	up_write(&sb->s_umount);
 	return 0;
@@ -1810,6 +1838,7 @@ static int thaw_super_locked(struct super_block *sb, enum freeze_holder who)
 	if (sb_rdonly(sb)) {
 		sb->s_writers.freeze_holders &= ~who;
 		sb->s_writers.frozen = SB_UNFROZEN;
+		wake_up_var(&sb->s_writers.frozen);
 		goto out;
 	}
 
@@ -1828,6 +1857,7 @@ static int thaw_super_locked(struct super_block *sb, enum freeze_holder who)
 
 	sb->s_writers.freeze_holders &= ~who;
 	sb->s_writers.frozen = SB_UNFROZEN;
+	wake_up_var(&sb->s_writers.frozen);
 	sb_freeze_unlock(sb, SB_FREEZE_FS);
 out:
 	deactivate_locked_super(sb);