[PATCH] tmpfs 6/7 write i_size_write

[PATCH] tmpfs 6/7 write i_size_write

From: Hugh Dickins <hugh@veritas.com>

mm/shmem.c was converted to i_size_read in -test1, and the remaining
references to a file's naked i_size are safely protected by i_sem;
but surely shmem_file_write must use i_size_write to update i_size.