[PATCH AUTOSEL for 4.9 136/190] tcm_fileio: Prevent information leak for short reads

From: Dmitry Monakhov [ Upstream commit f11b55d13563e9428c88c873f4f03a6bef11ec0a ] If we failed to read data from backing file (probably because some one truncate file under us), we must zerofill cmd's data, otherwise it will be returned as is. Most likely cmd's data are

[PATCH AUTOSEL for 4.9 136/190] tcm_fileio: Prevent information leak for short reads

From: Dmitry Monakhov [ Upstream commit f11b55d13563e9428c88c873f4f03a6bef11ec0a ] If we failed to read data from backing file (probably because some one truncate file under us), we must zerofill cmd's data, otherwise it will be returned as is. Most likely cmd's data are unitialized pages from