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-rw-r--r--fs/super.c44
1 files changed, 42 insertions, 2 deletions
diff --git a/fs/super.c b/fs/super.c
index fd9c02f543eb..83c5c8a60f5f 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -36,6 +36,7 @@
#include <linux/user_namespace.h>
#include "internal.h"
+static int thaw_super_locked(struct super_block *sb);
static LIST_HEAD(super_blocks);
static DEFINE_SPINLOCK(sb_lock);
@@ -934,6 +935,40 @@ void emergency_remount(void)
}
}
+static void do_thaw_all_callback(struct super_block *sb)
+{
+ down_write(&sb->s_umount);
+ if (sb->s_root && sb->s_flags & MS_BORN) {
+ emergency_thaw_bdev(sb);
+ thaw_super_locked(sb);
+ } else {
+ up_write(&sb->s_umount);
+ }
+}
+
+static void do_thaw_all(struct work_struct *work)
+{
+ __iterate_supers(do_thaw_all_callback);
+ kfree(work);
+ printk(KERN_WARNING "Emergency Thaw complete\n");
+}
+
+/**
+ * emergency_thaw_all -- forcibly thaw every frozen filesystem
+ *
+ * Used for emergency unfreeze of all filesystems via SysRq
+ */
+void emergency_thaw_all(void)
+{
+ struct work_struct *work;
+
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+ if (work) {
+ INIT_WORK(work, do_thaw_all);
+ schedule_work(work);
+ }
+}
+
/*
* Unnamed block devices are dummy devices used by virtual
* filesystems which don't use real block-devices. -- jrs
@@ -1503,11 +1538,10 @@ EXPORT_SYMBOL(freeze_super);
*
* Unlocks the filesystem and marks it writeable again after freeze_super().
*/
-int thaw_super(struct super_block *sb)
+static int thaw_super_locked(struct super_block *sb)
{
int error;
- down_write(&sb->s_umount);
if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
up_write(&sb->s_umount);
return -EINVAL;
@@ -1538,4 +1572,10 @@ out:
deactivate_locked_super(sb);
return 0;
}
+
+int thaw_super(struct super_block *sb)
+{
+ down_write(&sb->s_umount);
+ return thaw_super_locked(sb);
+}
EXPORT_SYMBOL(thaw_super);