LU-9491 llite: Handle multi-vec append write correctly

[fs/lustre-release.git] / lustre / llite / llite_internal.h

diff --git a/lustre/llite/llite_internal.h b/lustre/llite/llite_internal.h
index ec51a9a..bab7e68 100644 (file)
--- a/lustre/llite/llite_internal.h
+++ b/lustre/llite/llite_internal.h
@@ -1521,6 +1521,30 @@ __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
        struct iov_iter i;
        ssize_t bytes = 0;
 
+       /* Since LLITE updates file size at the end of I/O in
+        * vvp_io_commit_write(), append write has to be done in atomic when
+        * there are multiple segments because otherwise each iteration to
+        * __generic_file_aio_write() will see original file size */
+       if (unlikely(iocb->ki_filp->f_flags & O_APPEND && iter->nr_segs > 1)) {
+               struct iovec *iov_copy;
+               int count = 0;
+
+               OBD_ALLOC(iov_copy, sizeof(*iov_copy) * iter->nr_segs);
+               if (!iov_copy)
+                       return -ENOMEM;
+
+               iov_for_each(iov, i, *iter)
+                       iov_copy[count++] = iov;
+
+               bytes = __generic_file_aio_write(iocb, iov_copy, count,
+                                                &iocb->ki_pos);
+               OBD_FREE(iov_copy, sizeof(*iov_copy) * iter->nr_segs);
+
+               if (bytes > 0)
+                       iov_iter_advance(iter, bytes);
+               return bytes;
+       }
+
        iov_for_each(iov, i, *iter) {
                ssize_t res;