linux/include
Artur Paszkiewicz 3418d036c8 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>
2017-03-16 16:55:54 -07:00
..
acpi Merge branches 'acpi-bus', 'acpi-sleep' and 'acpi-processor' 2017-02-20 14:28:03 +01:00
asm-generic mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
clocksource
crypto net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
drm sched/headers: Prepare to remove the <linux/mm_types.h> dependency from <linux/sched.h> 2017-03-02 08:42:37 +01:00
dt-bindings scripts/spelling.txt: add "overide" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
keys KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload() 2017-03-02 10:09:00 +11:00
kvm
linux Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
math-emu
media media fixes for v4.11-rc2 2017-03-09 15:50:56 -08:00
memory
misc
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
pcmcia
ras
rdma sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
rxrpc
scsi scsi: mpt3sas: Avoid sleeping in interrupt context 2017-03-01 21:52:13 -05:00
soc ARC updates for 4.11 rc1 2017-02-22 10:33:53 -08:00
sound sched/headers: Prepare to remove spurious <linux/sched.h> inclusion dependencies 2017-03-02 08:42:41 +01:00
target Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
trace There was some breakage with the changes for jump labels in the 4.11 merge 2017-03-07 09:37:28 -08:00
uapi raid5-ppl: Partial Parity Log write logging implementation 2017-03-16 16:55:54 -07:00
video
xen Merge branch 'stable/for-linus-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb 2017-03-07 10:23:17 -08:00
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