aio: fix freeze protection of aio writes

[mirror_ubuntu-artful-kernel.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index c19755187ca592eeaeabf7c21d765897aba802aa..428484f2f8413dc6972da9857b3392264b9e6421 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1078,6 +1078,17 @@ static void aio_complete(struct kiocb *kiocb, long res, long res2)
        unsigned tail, pos, head;
        unsigned long   flags;
 
+       if (kiocb->ki_flags & IOCB_WRITE) {
+               struct file *file = kiocb->ki_filp;
+
+               /*
+                * Tell lockdep we inherited freeze protection from submission
+                * thread.
+                */
+               __sb_writers_acquired(file_inode(file)->i_sb, SB_FREEZE_WRITE);
+               file_end_write(file);
+       }
+
        /*
         * Special case handling for sync iocbs:
         *  - events go directly into the iocb for fast handling
@@ -1473,9 +1484,15 @@ static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored,
                return ret;
        ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
        if (!ret) {
+               req->ki_flags |= IOCB_WRITE;
                file_start_write(file);
                ret = aio_ret(req, file->f_op->write_iter(req, &iter));
-               file_end_write(file);
+               /*
+                * We release freeze protection in aio_complete().  Fool lockdep
+                * by telling it the lock got released so that it doesn't
+                * complain about held lock when we return to userspace.
+                */
+               __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
        }
        kfree(iovec);
        return ret;