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authorArtur Paszkiewicz <artur.paszkiewicz@intel.com>2017-03-09 09:59:59 +0100
committerShaohua Li <shli@fb.com>2017-03-16 16:55:54 -0700
commit3418d036c81dcb604b7c7c71b209d5890a8418aa (patch)
treed02a31103e09f82858bf149ebcb511e12ed6065a /drivers/md/Makefile
parentff875738edd44e3bc892d378deacc50bccc9d70c (diff)
downloadop-kernel-dev-3418d036c81dcb604b7c7c71b209d5890a8418aa.zip
op-kernel-dev-3418d036c81dcb604b7c7c71b209d5890a8418aa.tar.gz
raid5-ppl: Partial Parity Log write logging implementation
Implement the calculation of partial parity for a stripe and PPL write logging functionality. The description of PPL is added to the documentation. More details can be found in the comments in raid5-ppl.c. Attach a page for holding the partial parity data to stripe_head. Allocate it only if mddev has the MD_HAS_PPL flag set. Partial parity is the xor of not modified data chunks of a stripe and is calculated as follows: - reconstruct-write case: xor data from all not updated disks in a stripe - read-modify-write case: xor old data and parity from all updated disks in a stripe Implement it using the async_tx API and integrate into raid_run_ops(). It must be called when we still have access to old data, so do it when STRIPE_OP_BIODRAIN is set, but before ops_run_prexor5(). The result is stored into sh->ppl_page. Partial parity is not meaningful for full stripe write and is not stored in the log or used for recovery, so don't attempt to calculate it when stripe has STRIPE_FULL_WRITE. Put the PPL metadata structures to md_p.h because userspace tools (mdadm) will also need to read/write PPL. Warn about using PPL with enabled disk volatile write-back cache for now. It can be removed once disk cache flushing before writing PPL is implemented. Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/Makefile')
-rw-r--r--drivers/md/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 3cbda1a..4d48714 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -18,7 +18,7 @@ dm-cache-cleaner-y += dm-cache-policy-cleaner.o
dm-era-y += dm-era-target.o
dm-verity-y += dm-verity-target.o
md-mod-y += md.o bitmap.o
-raid456-y += raid5.o raid5-cache.o
+raid456-y += raid5.o raid5-cache.o raid5-ppl.o
# Note: link order is important. All raid personalities
# and must come before md.o, as they each initialise
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