Btrfs: don't use global block reservation for inode cache truncation

[deliverable/linux.git] / fs / read_write.c

diff --git a/fs/read_write.c b/fs/read_write.c
index f7b5a23b804b0955c72309a98dcd3dd088fd5bb4..e6ddc8dceb96fc48a8fbe379799d0efed52d2b4a 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -424,6 +424,9 @@ ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t
        const char __user *p;
        ssize_t ret;
 
+       if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
+               return -EINVAL;
+
        old_fs = get_fs();
        set_fs(get_ds());
        p = (__force const char __user *)buf;