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Linux 4.8 compat: Fix removal of bio->bi_rw member 

All users of bio->bi_rw have been replaced with compatibility wrappers.
This allows the kernel specific logic to be abstracted away, and for
each of the supported cases to be documented with the wrapper.  The
updated interfaces are as follows:

* void blk_queue_set_write_cache(struct request_queue *, bool, bool)
* boolean_t bio_is_flush(struct bio *)
* boolean_t bio_is_fua(struct bio *)
* boolean_t bio_is_discard(struct bio *)
* boolean_t bio_is_secure_erase(struct bio *)
* VDEV_WRITE_FLUSH_FUA

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #4951
This commit is contained in:
Brian Behlendorf 2016-08-09 11:22:30 -07:00
parent 689f093ebc
commit cf41432c70
4 changed files with 195 additions and 82 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

67
config/kernel-bio-op.m4 Normal file
View File

@ -0,0 +1,67 @@
dnl #
dnl # Linux 4.8 API,
dnl #
dnl # The bio_op() helper was introduced as a replacement for explicitly
dnl # checking the bio->bi_rw flags. The following checks are used to
dnl # detect if a specific operation is supported.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_REQ_OP_DISCARD], [
AC_MSG_CHECKING([whether REQ_OP_DISCARD is defined])
ZFS_LINUX_TRY_COMPILE([
#include <linux/blk_types.h>
],[
enum req_op op __attribute__ ((unused)) = REQ_OP_DISCARD;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_REQ_OP_DISCARD, 1,
[REQ_OP_DISCARD is defined])
],[
AC_MSG_RESULT(no)
])
])
AC_DEFUN([ZFS_AC_KERNEL_REQ_OP_SECURE_ERASE], [
AC_MSG_CHECKING([whether REQ_OP_SECURE_ERASE is defined])
ZFS_LINUX_TRY_COMPILE([
#include <linux/blk_types.h>
],[
enum req_op op __attribute__ ((unused)) = REQ_OP_SECURE_ERASE;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_REQ_OP_SECURE_DISCARD, 1,
[REQ_OP_SECURE_ERASE is defined])
],[
AC_MSG_RESULT(no)
])
])
AC_DEFUN([ZFS_AC_KERNEL_REQ_OP_FLUSH], [
AC_MSG_CHECKING([whether REQ_OP_FLUSH is defined])
ZFS_LINUX_TRY_COMPILE([
#include <linux/blk_types.h>
],[
enum req_op op __attribute__ ((unused)) = REQ_OP_FLUSH;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_REQ_OP_FLUSH, 1,
[REQ_OP_FLUSH is defined])
],[
AC_MSG_RESULT(no)
])
])
AC_DEFUN([ZFS_AC_KERNEL_BIO_BI_OPF], [
AC_MSG_CHECKING([whether bio->bi_opf is defined])
ZFS_LINUX_TRY_COMPILE([
#include <linux/bio.h>
],[
struct bio bio __attribute__ ((unused));
bio.bi_opf = 0;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_BIO_BI_OPF, 1, [bio->bi_opf is defined])
],[
AC_MSG_RESULT(no)
])
])

4
config/kernel.m4
View File

@ -23,6 +23,10 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
ZFS_AC_KERNEL_BIO_BVEC_ITER
ZFS_AC_KERNEL_BIO_FAILFAST_DTD
ZFS_AC_KERNEL_REQ_FAILFAST_MASK
ZFS_AC_KERNEL_REQ_OP_DISCARD
ZFS_AC_KERNEL_REQ_OP_SECURE_ERASE
ZFS_AC_KERNEL_REQ_OP_FLUSH
ZFS_AC_KERNEL_BIO_BI_OPF
ZFS_AC_KERNEL_BIO_END_IO_T_ARGS
ZFS_AC_KERNEL_BIO_RW_BARRIER
ZFS_AC_KERNEL_BIO_RW_DISCARD

175
include/linux/blkdev_compat.h
View File

@ -37,35 +37,24 @@ typedef unsigned __bitwise__ fmode_t;
#endif /* HAVE_FMODE_T */
/*
* 2.6.36 API change,
* 4.7 - 4.x API,
* The blk_queue_write_cache() interface has replaced blk_queue_flush()
* interface. However, the new interface is GPL-only thus we implement
* our own trivial wrapper when the GPL-only version is detected.
*
* 2.6.36 - 4.6 API,
* The blk_queue_flush() interface has replaced blk_queue_ordered()
* interface. However, while the old interface was available to all the
* new one is GPL-only. Thus if the GPL-only version is detected we
* implement our own trivial helper compatibility funcion. The hope is
* that long term this function will be opened up.
* implement our own trivial helper.
*
* 2.6.x - 2.6.35
* Legacy blk_queue_ordered() interface.
*/
#if defined(HAVE_BLK_QUEUE_FLUSH) && defined(HAVE_BLK_QUEUE_FLUSH_GPL_ONLY)
#define blk_queue_flush __blk_queue_flush
static inline void
__blk_queue_flush(struct request_queue *q, unsigned int flags)
{
q->flush_flags = flags & (REQ_FLUSH | REQ_FUA);
}
#endif /* HAVE_BLK_QUEUE_FLUSH && HAVE_BLK_QUEUE_FLUSH_GPL_ONLY */
/*
* 4.7 API change,
* The blk_queue_write_cache() interface has replaced blk_queue_flush()
* interface. However, while the new interface is GPL-only. Thus if the
* GPL-only version is detected we implement our own trivial helper
* compatibility funcion.
*/
#if defined(HAVE_BLK_QUEUE_WRITE_CACHE) && \
defined(HAVE_BLK_QUEUE_WRITE_CACHE_GPL_ONLY)
#define blk_queue_write_cache __blk_queue_write_cache
static inline void
__blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
blk_queue_set_write_cache(struct request_queue *q, bool wc, bool fua)
{
#if defined(HAVE_BLK_QUEUE_WRITE_CACHE_GPL_ONLY)
spin_lock_irq(q->queue_lock);
if (wc)
queue_flag_set(QUEUE_FLAG_WC, q);
@ -76,8 +65,19 @@ __blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
else
queue_flag_clear(QUEUE_FLAG_FUA, q);
spin_unlock_irq(q->queue_lock);
}
#elif defined(HAVE_BLK_QUEUE_WRITE_CACHE)
blk_queue_write_cache(q, wc, fua);
#elif defined(HAVE_BLK_QUEUE_FLUSH_GPL_ONLY)
if (wc)
q->flush_flags |= REQ_FLUSH;
if (fua)
q->flush_flags |= REQ_FUA;
#elif defined(HAVE_BLK_QUEUE_FLUSH)
blk_queue_flush(q, (wc ? REQ_FLUSH : 0) | (fua ? REQ_FUA : 0));
#else
blk_queue_ordered(q, QUEUE_ORDERED_DRAIN, NULL);
#endif
}
/*
* Most of the blk_* macros were removed in 2.6.36. Ostensibly this was
@ -301,68 +301,121 @@ bio_set_flags_failfast(struct block_device *bdev, int *flags)
* allow richer semantics to be expressed to the block layer. It is
* the block layers responsibility to choose the correct way to
* implement these semantics.
*
* The existence of these flags implies that REQ_FLUSH an REQ_FUA are
* defined. Thus we can safely define VDEV_REQ_FLUSH and VDEV_REQ_FUA
* compatibility macros.
*
* Linux 4.8 renamed the REQ_FLUSH to REQ_PREFLUSH but there was no
* functional change in behavior.
*/
#ifdef WRITE_FLUSH_FUA
#define VDEV_WRITE_FLUSH_FUA WRITE_FLUSH_FUA
#ifdef REQ_PREFLUSH
#define VDEV_REQ_FLUSH REQ_PREFLUSH
#define VDEV_REQ_FUA REQ_FUA
#else
#define VDEV_REQ_FLUSH REQ_FLUSH
#define VDEV_REQ_FUA REQ_FUA
#endif
#else
#define VDEV_WRITE_FLUSH_FUA WRITE_BARRIER
#ifdef HAVE_BIO_RW_BARRIER
#define VDEV_REQ_FLUSH (1 << BIO_RW_BARRIER)
#define VDEV_REQ_FUA (1 << BIO_RW_BARRIER)
#else
#define VDEV_REQ_FLUSH REQ_HARDBARRIER
#define VDEV_REQ_FUA REQ_FUA
#endif
#endif
/*
* 2.6.28 - 2.6.35 API,
* BIO_RW_DISCARD
* 4.8 - 4.x API,
* REQ_OP_FLUSH
*
* 4.8-rc0 - 4.8-rc1,
* REQ_PREFLUSH
*
* 2.6.36 - 4.7 API,
* REQ_FLUSH
*
* 2.6.x - 2.6.35 API,
* HAVE_BIO_RW_BARRIER
*
* Used to determine if a cache flush has been requested. This check has
* been left intentionally broad in order to cover both a legacy flush
* and the new preflush behavior introduced in Linux 4.8. This is correct
* in all cases but may have a performance impact for some kernels. It
* has the advantage of minimizing kernel specific changes in the zvol code.
*/
static inline boolean_t
bio_is_flush(struct bio *bio)
{
#if defined(HAVE_REQ_OP_FLUSH) && defined(HAVE_BIO_BI_OPF)
return ((bio_op(bio) == REQ_OP_FLUSH) || (bio->bi_opf & REQ_PREFLUSH));
#elif defined(REQ_PREFLUSH) && defined(HAVE_BIO_BI_OPF)
return (bio->bi_opf & REQ_PREFLUSH);
#elif defined(REQ_PREFLUSH) && !defined(HAVE_BIO_BI_OPF)
return (bio->bi_rw & REQ_PREFLUSH);
#elif defined(REQ_FLUSH)
return (bio->bi_rw & REQ_FLUSH);
#elif defined(HAVE_BIO_RW_BARRIER)
return (bio->bi_rw & (1 << BIO_RW_BARRIER));
#else
#error "Allowing the build will cause flush requests to be ignored. Please "
"file an issue report at: https://github.com/zfsonlinux/zfs/issues/new"
#endif
}
/*
* 4.8 - 4.x API,
* REQ_FUA flag moved to bio->bi_opf
*
* 2.6.x - 4.7 API,
* REQ_FUA
*/
static inline boolean_t
bio_is_fua(struct bio *bio)
{
#if defined(HAVE_BIO_BI_OPF)
return (bio->bi_opf & REQ_FUA);
#elif defined(REQ_FUA)
return (bio->bi_rw & REQ_FUA);
#else
#error "Allowing the build will cause fua requests to be ignored. Please "
"file an issue report at: https://github.com/zfsonlinux/zfs/issues/new"
#endif
}
/*
* 4.8 - 4.x API,
* REQ_OP_DISCARD
*
* 2.6.36 - 4.7 API,
* REQ_DISCARD
*
* 4.8 - 4.x API,
* REQ_OP_DISCARD
* 2.6.28 - 2.6.35 API,
* BIO_RW_DISCARD
*
* In all cases the normal I/O path is used for discards. The only
* difference is how the kernel tags individual I/Os as discards.
*/
#ifdef QUEUE_FLAG_DISCARD
static inline boolean_t
bio_is_discard(struct bio *bio)
{
#if defined(HAVE_BIO_RW_DISCARD)
return (bio->bi_rw & (1 << BIO_RW_DISCARD));
#if defined(HAVE_REQ_OP_DISCARD)
return (bio_op(bio) == REQ_OP_DISCARD);
#elif defined(REQ_DISCARD)
return (bio->bi_rw & REQ_DISCARD);
#else
return (bio_op(bio) == REQ_OP_DISCARD);
#endif
}
#elif defined(HAVE_BIO_RW_DISCARD)
return (bio->bi_rw & (1 << BIO_RW_DISCARD));
#else
#error "Allowing the build will cause discard requests to become writes "
"potentially triggering the DMU_MAX_ACCESS assertion. Please file a "
"potentially triggering the DMU_MAX_ACCESS assertion. Please file "
"an issue report at: https://github.com/zfsonlinux/zfs/issues/new"
#endif
}
/*
* 4.8 - 4.x API,
* REQ_OP_SECURE_ERASE
*
* 2.6.36 - 4.7 API,
* REQ_SECURE
*
* 2.6.x - 2.6.35 API,
* Unsupported by kernel
*/
static inline boolean_t
bio_is_secure_erase(struct bio *bio)
{
#if defined(HAVE_REQ_OP_SECURE_ERASE)
return (bio_op(bio) == REQ_OP_SECURE_ERASE);
#elif defined(REQ_SECURE)
return (bio->bi_rw & REQ_SECURE);
#else
return (0);
#endif
}
/*
* 2.6.33 API change

31
module/zfs/zvol.c
View File

@ -707,20 +707,16 @@ zvol_discard(struct bio *bio)
return (SET_ERROR(EIO));
/*
* Align the request to volume block boundaries when REQ_SECURE is
* available, but not requested. If we don't, then this will force
* dnode_free_range() to zero out the unaligned parts, which is slow
* (read-modify-write) and useless since we are not freeing any space
* by doing so. Kernels that do not support REQ_SECURE (2.6.32 through
* 2.6.35) will not receive this optimization.
* Align the request to volume block boundaries when a secure erase is
* not required. This will prevent dnode_free_range() from zeroing out
* the unaligned parts which is slow (read-modify-write) and useless
* since we are not freeing any space by doing so.
*/
#ifdef REQ_SECURE
if (!(bio->bi_rw & REQ_SECURE)) {
if (!bio_is_secure_erase(bio)) {
start = P2ROUNDUP(start, zv->zv_volblocksize);
end = P2ALIGN(end, zv->zv_volblocksize);
size = end - start;
}
#endif
if (start >= end)
return (0);
@ -812,7 +808,7 @@ zvol_request(struct request_queue *q, struct bio *bio)
goto out2;
}
if (bio_is_discard(bio)) {
if (bio_is_discard(bio) || bio_is_secure_erase(bio)) {
error = zvol_discard(bio);
goto out2;
}
@ -821,14 +817,14 @@ zvol_request(struct request_queue *q, struct bio *bio)
* Some requests are just for flush and nothing else.
*/
if (uio.uio_resid == 0) {
if (bio->bi_rw & VDEV_REQ_FLUSH)
if (bio_is_flush(bio))
zil_commit(zv->zv_zilog, ZVOL_OBJ);
goto out2;
}
error = zvol_write(zv, &uio,
((bio->bi_rw & (VDEV_REQ_FUA|VDEV_REQ_FLUSH)) ||
zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS));
bio_is_flush(bio) || bio_is_fua(bio) ||
zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS);
} else
error = zvol_read(zv, &uio);
@ -1290,14 +1286,7 @@ zvol_alloc(dev_t dev, const char *name)
goto out_kmem;
blk_queue_make_request(zv->zv_queue, zvol_request);
#ifdef HAVE_BLK_QUEUE_WRITE_CACHE
blk_queue_write_cache(zv->zv_queue, B_TRUE, B_TRUE);
#elif defined(HAVE_BLK_QUEUE_FLUSH)
blk_queue_flush(zv->zv_queue, VDEV_REQ_FLUSH | VDEV_REQ_FUA);
#else
blk_queue_ordered(zv->zv_queue, QUEUE_ORDERED_DRAIN, NULL);
#endif /* HAVE_BLK_QUEUE_FLUSH */
blk_queue_set_write_cache(zv->zv_queue, B_TRUE, B_TRUE);
zv->zv_disk = alloc_disk(ZVOL_MINORS);
if (zv->zv_disk == NULL)