diff options
| author | Etienne Dechamps <[email protected]> | 2013-02-24 11:22:07 +0000 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2013-02-24 10:22:34 -0800 |
| commit | d9b0ebbe824469d178a05b0fb9004e4afce86009 (patch) | |
| tree | 9c7a5c87282f39a353e37cb51e8ba57bada60ada /config | |
| parent | d75af3c0ebb4e31ece087aeecfeff282cb6f1361 (diff) | |
Remove the bio_empty_barrier() check.
To determine whether the kernel is capable of handling empty barrier
BIOs, we check for the presence of the bio_empty_barrier() macro,
which was introduced in 2.6.24. If this macro is defined, then we can
flush disk vdevs; if it isn't, then flushing is disabled.
Unfortunately, the bio_empty_barrier() macro was removed in 2.6.37,
even though the kernel is still capable of handling empty barrier BIOs.
As a result, flushing is effectively disabled on kernels >= 2.6.37,
meaning that starting from this kernel version, zfs doesn't use
barriers to guarantee on-disk data consistency. This is quite bad and
can lead to potential data corruption on power failures.
This patch fixes the issue by removing the configure check for
bio_empty_barrier(), as we don't support kernels <= 2.6.24 anymore.
Thanks to Richard Kojedzinszky for catching this nasty bug.
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #1318
Diffstat (limited to 'config')
| -rw-r--r-- | config/kernel-bio-empty-barrier.m4 | 19 | ||||
| -rw-r--r-- | config/kernel.m4 | 1 |
2 files changed, 0 insertions, 20 deletions
diff --git a/config/kernel-bio-empty-barrier.m4 b/config/kernel-bio-empty-barrier.m4 deleted file mode 100644 index fda16b3ab..000000000 --- a/config/kernel-bio-empty-barrier.m4 +++ /dev/null @@ -1,19 +0,0 @@ -dnl # -dnl # 2.6.24 API change -dnl # Empty write barriers are now supported and we should use them. -dnl # -AC_DEFUN([ZFS_AC_KERNEL_BIO_EMPTY_BARRIER], [ - AC_MSG_CHECKING([whether bio_empty_barrier() is defined]) - ZFS_LINUX_TRY_COMPILE([ - #include <linux/bio.h> - ],[ - struct bio bio; - (void)bio_empty_barrier(&bio); - ],[ - AC_MSG_RESULT(yes) - AC_DEFINE(HAVE_BIO_EMPTY_BARRIER, 1, - [bio_empy_barrier() is defined]) - ],[ - AC_MSG_RESULT(no) - ]) -]) diff --git a/config/kernel.m4 b/config/kernel.m4 index 5623785fb..9d5aa4621 100644 --- a/config/kernel.m4 +++ b/config/kernel.m4 @@ -16,7 +16,6 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [ ZFS_AC_KERNEL_INVALIDATE_BDEV_ARGS ZFS_AC_KERNEL_BDEV_LOGICAL_BLOCK_SIZE ZFS_AC_KERNEL_BDEV_PHYSICAL_BLOCK_SIZE - ZFS_AC_KERNEL_BIO_EMPTY_BARRIER ZFS_AC_KERNEL_BIO_FAILFAST ZFS_AC_KERNEL_BIO_FAILFAST_DTD ZFS_AC_KERNEL_REQ_FAILFAST_MASK |