diff options
Diffstat (limited to 'pkgs/os-specific/linux/zfs/gcc-4.8.patch')
| -rw-r--r-- | pkgs/os-specific/linux/zfs/gcc-4.8.patch | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/pkgs/os-specific/linux/zfs/gcc-4.8.patch b/pkgs/os-specific/linux/zfs/gcc-4.8.patch new file mode 100644 index 000000000000..341360163761 --- /dev/null +++ b/pkgs/os-specific/linux/zfs/gcc-4.8.patch @@ -0,0 +1,114 @@ +commit 0f62f3f9abc4bfa0bcafee9bfa3d55e91dcb371d +Author: Brian Behlendorf <behlendorf1@llnl.gov> +Date: Tue Jan 14 09:39:13 2014 -0800 + + Disable GCCs aggressive loop optimization + + GCC >+ 4.8's aggressive loop optimization breaks some of the iterators + over the dn_blkptr[] pseudo-array in dnode_phys. Since dn_blkptr[] is + defined as a single-element array, GCC believes an iterator can only + access index 0 and will unroll the loop into a single iteration. + + One way to resolve the issue would be to cast the array to a pointer + and fix all the iterators that might break. The only loop where it + is known to cause a problem is this loop in dmu_objset_write_ready(): + + for (i = 0; i < dnp->dn_nblkptr; i++) + bp->blk_fill += dnp->dn_blkptr[i].blk_fill; + + In the common case where dn_nblkptr is 3, the loop is only executed a + single time and "i" is equal to 1 following the loop. + + The specific breakage caused by this problem is that the blk_fill of + root block pointers wouldn't be set properly when more than one blkptr + is in use (when no indrect blocks are needed). + + The simple reproducing sequence is: + + zpool create tank /tank.img + zdb -ddddd tank 0 + + Notice that "fill=31", however, there are two L0 indirect blocks with + "F=31" and "F=5". The fill count should be 36 rather than 31. This + problem causes an assert to be hit in a simple "zdb tank" when built + with --enable-debug. + + However, this approach was not taken because we need to be absolutely + sure we catch all instances of this unwanted optimization. Therefore, + the build system has been updated to detect if GCC supports the + aggressive loop optimization. If it does the optimization will be + explicitly disabled using the -fno-aggressive-loop-optimization option. + + Original-fix-by: Tim Chase <tim@chase2k.com> + Signed-off-by: Tim Chase <tim@chase2k.com> + Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> + Closes #2010 + Closes #2051 + +diff --git a/config/Rules.am b/config/Rules.am +index e3fa5b5..24f9426 100644 +--- a/config/Rules.am ++++ b/config/Rules.am +@@ -1,8 +1,10 @@ + DEFAULT_INCLUDES = -include ${top_builddir}/zfs_config.h + + AM_LIBTOOLFLAGS = --silent +-AM_CFLAGS = -Wall -Wstrict-prototypes +-AM_CFLAGS += -fno-strict-aliasing ${NO_UNUSED_BUT_SET_VARIABLE} ${DEBUG_CFLAGS} ++AM_CFLAGS = ${DEBUG_CFLAGS} -Wall -Wstrict-prototypes ++AM_CFLAGS += ${NO_UNUSED_BUT_SET_VARIABLE} ++AM_CFLAGS += ${NO_AGGRESSIVE_LOOP_OPTIMIZATIONS} ++AM_CFLAGS += -fno-strict-aliasing + AM_CPPFLAGS = -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT + AM_CPPFLAGS += -D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 + AM_CPPFLAGS += -D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\" +diff --git a/config/always-no-aggressive-loop-optimizations.m4 b/config/always-no-aggressive-loop-optimizations.m4 +new file mode 100644 +index 0000000..8f2115a +--- /dev/null ++++ b/config/always-no-aggressive-loop-optimizations.m4 +@@ -0,0 +1,20 @@ ++dnl # ++dnl # Check if gcc supports -fno-aggressive-loop-optimizations ++dnl # ++AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_NO_AGGRESSIVE_LOOP_OPTIMIZATIONS], [ ++ AC_MSG_CHECKING([for -fno-aggressive-loop-optimizations support]) ++ ++ saved_flags="$CFLAGS" ++ CFLAGS="$CFLAGS -fno-aggressive-loop-optimizations" ++ ++ AC_RUN_IFELSE([AC_LANG_PROGRAM([], [])], [ ++ NO_AGGRESSIVE_LOOP_OPTIMIZATIONS=-fno-aggressive-loop-optimizations ++ AC_MSG_RESULT([yes]) ++ ], [ ++ NO_AGGRESSIVE_LOOP_OPTIMIZATIONS= ++ AC_MSG_RESULT([no]) ++ ]) ++ ++ CFLAGS="$saved_flags" ++ AC_SUBST([NO_AGGRESSIVE_LOOP_OPTIMIZATIONS]) ++]) +diff --git a/config/kernel.m4 b/config/kernel.m4 +index cbf0ca3..62a9b42 100644 +--- a/config/kernel.m4 ++++ b/config/kernel.m4 +@@ -104,6 +104,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [ + dnl # -Wall -fno-strict-aliasing -Wstrict-prototypes and other + dnl # compiler options are added by the kernel build system. + KERNELCPPFLAGS="$KERNELCPPFLAGS $NO_UNUSED_BUT_SET_VARIABLE" ++ KERNELCPPFLAGS="$KERNELCPPFLAGS $NO_AGGRESSIVE_LOOP_OPTIMIZATIONS" + KERNELCPPFLAGS="$KERNELCPPFLAGS -DHAVE_SPL -D_KERNEL" + KERNELCPPFLAGS="$KERNELCPPFLAGS -DTEXT_DOMAIN=\\\"zfs-linux-kernel\\\"" + +diff --git a/config/zfs-build.m4 b/config/zfs-build.m4 +index 005185b..477b916 100644 +--- a/config/zfs-build.m4 ++++ b/config/zfs-build.m4 +@@ -62,6 +62,7 @@ AC_DEFUN([ZFS_AC_DEBUG_DMU_TX], [ + + AC_DEFUN([ZFS_AC_CONFIG_ALWAYS], [ + ZFS_AC_CONFIG_ALWAYS_NO_UNUSED_BUT_SET_VARIABLE ++ ZFS_AC_CONFIG_ALWAYS_NO_AGGRESSIVE_LOOP_OPTIMIZATIONS + ]) + + AC_DEFUN([ZFS_AC_CONFIG], [ |