An attempt to freeze a filesystem that does not support such operation is
reported as EOPNOTSUPP to user. Running unfreeze to the same filesystem
returns EINVAL. Later is a little misleading, users can mix that message
with return value from unfreezing when filesystem is not frozen.
Signed-off-by: Sami Kerola <kerol...@iki.fi>
---
fs/ioctl.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index cb9b02940805..1d6372ef4008 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -566,6 +566,10 @@ static int ioctl_fsthaw(struct file *filp)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
+ /* If filesystem doesn't support thaw feature, return. */
+ if (!sb->s_op->unfreeze_fs)
+ return -EOPNOTSUPP;
+
/* Thaw */
if (sb->s_op->thaw_super)
return sb->s_op->thaw_super(sb);
--
2.11.0
