[PATCHSET 2.6.36-rc2] block, dm: finish REQ_FLUSH/FUA conversion
Tejun Heo
This patchset converts dm to REQ_FLUSH/FUA, which was the last
remaining one. I've put patches on top of the previous patches for
easier review. The series can be trivially reordered so that the
order is more logical. Jens, please let me know if you want it to be
reordered.
The dm conversion is _lightly_ tested. Please proceed with caution.
In particular, I haven't tested dm implementation at all. So, it
probably is best to hold off merging these bits until dm people can
verify the conversion is correct.
0001-block-make-__blk_rq_prep_clone-copy-most-command-fla.patch
0002-dm-implement-REQ_FLUSH-FUA-support.patch
0003-dm-relax-ordering-of-bio-based-flush-implementation.patch
0004-block-remove-the-WRITE_BARRIER-flag.patch
Differences from the previous attempt[1] are,
* I was wrong when I wrote that flush retry logic was dropped. What
got dropped was -EOPNOTSUPP handling. The retry behavior used by
multipath remains the same. As blindly retrying flushes could be
dangerous, a FIXME comment is added.
* bio-based dm now also advertises REQ_FLUSH | REQ_FUA capability as
block layer now filters out REQ_FLUSH if not supported by the queue.
* 0002-dm-implement-REQ_FLUSH-FUA-support.patch added to update
__blk_rq_prep_clone() to copy most REQ_* flags including FLUSH and
FUA and request-based dm now advertises REQ_FLUSH | REQ_FUA support.
* dm_request_fn() now explicitly plugs other requests while a flush
request is in progress. This is to avoid starving flush sequence
which uses device draining to check whether each step is complete.
* 0003-block-remove-the-WRITE_BARRIER-flag.patch added to drop
needless ordering around flush handling.
This patchset is on top of "block, fs: replace HARDBARRIER with
FLUSH/FUA" patchset[2] and available in the following git tree
git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git flush-fua
and contains the following changes.
block/blk-core.c | 4
drivers/md/dm-crypt.c | 2
drivers/md/dm-io.c | 20 --
drivers/md/dm-log.c | 2
drivers/md/dm-raid1.c | 8 -
drivers/md/dm-region-hash.c | 16 +-
drivers/md/dm-snap-persistent.c | 2
drivers/md/dm-snap.c | 6
drivers/md/dm-stripe.c | 2
drivers/md/dm.c | 277 +++++++++++++++-------------------------
include/linux/blk_types.h | 1
include/linux/fs.h | 3
12 files changed, 131 insertions(+), 212 deletions(-)
Thanks.
--
tejun
[1] http://thread.gmane.org/gmane.linux.raid/29100/focus=29104
[2] http://thread.gmane.org/gmane.linux.kernel/1022363
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Tejun Heo
There's no reason to omit other command flags and REQ_FUA needs to be
copied to implement FUA support in request-based dm.
REQ_COMMON_MASK which specifies flags to be copied from bio to request
already identifies all the command flags. Define REQ_CLONE_MASK to be
the same as REQ_COMMON_MASK for clarity and make __blk_rq_prep_clone()
copy all flags in the mask.
Signed-off-by: Tejun Heo <t...@kernel.org>
---
block/blk-core.c | 4 +---
include/linux/blk_types.h | 1 +
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 495bdc4..2a5b192 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2505,9 +2505,7 @@ EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
static void __blk_rq_prep_clone(struct request *dst, struct request *src)
{
dst->cpu = src->cpu;
- dst->cmd_flags = (rq_data_dir(src) | REQ_NOMERGE);
- if (src->cmd_flags & REQ_DISCARD)
- dst->cmd_flags |= REQ_DISCARD;
+ dst->cmd_flags = (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE;
dst->cmd_type = src->cmd_type;
dst->__sector = blk_rq_pos(src);
dst->__data_len = blk_rq_bytes(src);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 1797994..36edadf 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -168,6 +168,7 @@ enum rq_flag_bits {
#define REQ_COMMON_MASK \
(REQ_WRITE | REQ_FAILFAST_MASK | REQ_HARDBARRIER | REQ_SYNC | \
REQ_META | REQ_DISCARD | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
+#define REQ_CLONE_MASK REQ_COMMON_MASK
#define REQ_UNPLUG (1 << __REQ_UNPLUG)
#define REQ_RAHEAD (1 << __REQ_RAHEAD)
--
1.7.1
Tejun Heo
It's unused now.
Signed-off-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Tejun Heo <t...@kernel.org>
---
include/linux/fs.h | 3 ---
1 files changed, 0 insertions(+), 3 deletions(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 32703a9..6b0f6e9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -135,7 +135,6 @@ struct inodes_stat_t {
* immediately after submission. The write equivalent
* of READ_SYNC.
* WRITE_ODIRECT_PLUG Special case write for O_DIRECT only.
- * WRITE_BARRIER DEPRECATED. Always fails. Use FLUSH/FUA instead.
* WRITE_FLUSH Like WRITE_SYNC but with preceding cache flush.
* WRITE_FUA Like WRITE_SYNC but data is guaranteed to be on
* non-volatile media on completion.
@@ -157,8 +156,6 @@ struct inodes_stat_t {
#define WRITE_SYNC (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG)
#define WRITE_ODIRECT_PLUG (WRITE | REQ_SYNC)
#define WRITE_META (WRITE | REQ_META)
-#define WRITE_BARRIER (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG | \
- REQ_HARDBARRIER)
#define WRITE_FLUSH (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG | \
REQ_FLUSH)
#define WRITE_FUA (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG | \
--
1.7.1
Tejun Heo
> The dm conversion is _lightly_ tested. Please proceed with caution.
> In particular, I haven't tested dm implementation at all.
requested-based dm
--
tejun
Mike Snitzer
Tejun Heo <t...@kernel.org> wrote:
> Currently __blk_rq_prep_clone() copies only REQ_WRITE and REQ_DISCARD.
> There's no reason to omit other command flags and REQ_FUA needs to be
> copied to implement FUA support in request-based dm.
>
> REQ_COMMON_MASK which specifies flags to be copied from bio to request
> already identifies all the command flags. Define REQ_CLONE_MASK to be
> the same as REQ_COMMON_MASK for clarity and make __blk_rq_prep_clone()
> copy all flags in the mask.
>
> Signed-off-by: Tejun Heo <t...@kernel.org>
Looks great.
Acked-by: Mike Snitzer <sni...@redhat.com>