autofs: don't get stuck in a loop if vfs_write() returns an error

__vfs_write() returns a negative value in a error case.

Link: http://lkml.kernel.org/r/20160616083108.6278.65815.stgit@pluto.themaw.net
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 0146d911f468ca46d5fe7c946851c500b624ccb9..631f1554c87b7d73b9afc7834392ce6e279c7d6d 100644 (file)
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -66,11 +66,12 @@ static int autofs4_write(struct autofs_sb_info *sbi,
        set_fs(KERNEL_DS);
 
        mutex_lock(&sbi->pipe_mutex);
-       wr = __vfs_write(file, data, bytes, &file->f_pos);
-       while (bytes && wr) {
+       while (bytes) {
+               wr = __vfs_write(file, data, bytes, &file->f_pos);
+               if (wr <= 0)
+                       break;
                data += wr;
                bytes -= wr;
-               wr = __vfs_write(file, data, bytes, &file->f_pos);
        }
        mutex_unlock(&sbi->pipe_mutex);