Btrfs: add rw argument to merge_bio_hook()

We'll want to merge writes so they can fill a full RAID[56] stripe, but
not necessarily reads.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Btrfs: RAID5 and RAID6

This builds on David Woodhouse's original Btrfs raid5/6 implementation.
The code has changed quite a bit, blame Chris Mason for any bugs.

Read/modify/write is done after the higher levels of the filesystem have
prepared a given bio.  This means the higher layers are not responsible
for building full stripes, and they don't need to query for the topology
of the extents that may get allocated during delayed allocation runs.
It also means different files can easily share the same stripe.

But, it does expose us to incorrect parity if we crash or lose power
while doing a read/modify/write cycle.  This will be addressed in a
later commit.

Scrub is unable to repair crc errors on raid5/6 chunks.

Discard does not work on raid5/6 (yet)

The stripe size is fixed at 64KiB per disk.  This will be tunable
in a later commit.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Btrfs: Add a stripe cache to raid56

The stripe cache allows us to avoid extra read/modify/write cycles
by caching the pages we read off the disk.  Pages are cached when:

* They are read in during a read/modify/write cycle

* They are written during a read/modify/write cycle

* They are involved in a parity rebuild

Pages are not cached if we're doing a full stripe write.  We're
assuming that a full stripe write won't be followed by another
partial stripe write any time soon.

This provides a substantial boost in performance for workloads that
synchronously modify adjacent offsets in the file, and for the parity
rebuild use case in general.

The size of the stripe cache isn't tunable (yet) and is set at 1024
entries.

Example on flash: dd if=/dev/zero of=/mnt/xxx bs=4K oflag=direct

Without the stripe cache  -- 2.1MB/s
With the stripe cache 21MB/s

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Btrfs: add a plugging callback to raid56 writes

Buffered writes and DIRECT_IO writes will often break up
big contiguous changes to the file into sub-stripe writes.

This adds a plugging callback to gather those smaller writes full stripe
writes.

Example on flash:

fio job to do 64K writes in batches of 3 (which makes a full stripe):

With plugging: 450MB/s
Without plugging: 220MB/s

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Btrfs: fix cluster alignment for mount -o ssd

With the new raid56 code, we want to make sure we're
properly aligning our allocation clusters with -o ssd

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Btrfs: reduce lock contention on extent buffer locks

The extent buffers have a refs_lock which we use to make coordinate freeing
the extent buffer with operations on the radix tree.  On tree roots and
other extent buffers that very cache hot, this can be highly contended.

These are also the extent buffers that are basically pinned in memory.
This commit adds code to cmpxchg our way through the ref modifications,
and as long as the result of the reference change is still pinned in
ram, we skip the expensive spinlock.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Btrfs: reduce CPU contention while waiting for delayed extent operations

We batch up operations to the extent allocation tree, which allows
us to deal with the recursive nature of using the extent allocation
tree to allocate extents to the extent allocation tree.

It also provides a mechanism to sort and collect extent
operations, which makes it much more efficient to record extents
that are close together.

The delayed extent operations must all be finished before the
running transaction commits, so we have code to make sure and run a few
of the batched operations when closing our transaction handles.

This creates a great deal of contention for the locks in the
delayed extent operation tree, and also contention for the lock on the
extent allocation tree itself.  All the extra contention just slows
down the operations and doesn't get things done any faster.

This commit changes things to use a wait queue instead.  As procs
want to run the delayed operations, one of them races in and gets
permission to hit the tree, and the others step back and wait for
progress to be made.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
mtd: davinci_nand: fix modular build with CONFIG_OF=y

Commit cdeadd712f52b16a9285386d61ee26fd14eb4085 (mtd: nand: davinci: add OF
support for davinci nand controller) has never been really build tested with
the driver as a module.  When the driver is built-in, the missing semicolon
after structure initializer is "compensated" by MODULE_DEVICE_TABLE() macro
being empty and so the initializer using the trailing semicolon on the next
line; when the driver is built as a module, compilation error ensues, and as
the 'davinci_all_defconfig' has the NAND driver modular, this error prevents
DaVinci family kernel from building...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@vger.kernel.org # 3.7
mtd: docg3 fix missing bitreverse lib

Fix missing dependency which can cause a build error such
as: ERROR: "byte_rev_table" [drivers/mtd/devices/docg3.ko]
undefined!

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
mtd: gpmi: Always report ECC stats and return max_bitflips

Always report corrected and failed ECC stats back up to the MTD layer.  Also
return max_bitflips from read_page() as is expected from NAND drivers now.

Signed-off-by: Zach Sadecki <zsadecki@itwatchdogs.com>
Acked-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: cmdlinepart: fix skipping zero sized partition

Decrement index i after skipping a zero sized partition.  On next loop
iteration, the index will be the same as before, but the data will be
new as it was moved when earlier partition was skipped.

Signed-off-by: Christopher Cordahi <christophercordahi@nanometrics.ca>
Acked-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: cmdlinepart: skip partitions truncated to zero

Perform flash size truncation before skipping zero sized partition
so that if the result is a zero sized, it will be skipped like the
others.

Signed-off-by: Christopher Cordahi <christophercordahi@nanometrics.ca>
Acked-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: cmdlinepart: describe mtd ordering

The mtd documentation makes no mention of the useful feature whereby
partitions' logical ordering need not match their physical ordering.
Truncation of parts, skipping of zero sized parts, and handling of
overlapping parts are similarly not mentioned.

This updates the comments at the top of file describing the command
line parsing as currently implemented.   I proposed this in
http://lists.infradead.org/pipermail/linux-mtd/2012-December/045314.html

Signed-off-by: Christopher Cordahi <christophercordahi@nanometrics.ca>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: cmdlinepart: update /proc/mtd comment

/proc/mtd doesn't contain the mtd-id of the device, but the part name from the
command line.  This corrects what I believe is an obsolete comment from commit
a0ee24a03b1c06813c814b9f70946c8984752f01.

Signed-off-by: Christopher Cordahi <christophercordahi@nanometrics.ca>
Cc: Philip Rakity <prakity@yahoo.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: rename random32() to prandom_u32()

Use more preferable function name which implies using a pseudo-random
number generator.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: m25p80: Flash protection support for STmicro chips

This patch adds generic support for flash protection on STmicro chips.
On chips with less than 3 protection bits, the unused bits are don't cares
and so can be written anyway. The lock function will only change the
protection bits if it would not unlock other areas. Similarly, the unlock
function will not lock currently unlocked areas. Tested on the m25p64.

Signed-off-by: Austin Boyle <Austin.Boyle@aviatnet.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: mxc_nand: compress ID info for send_read_id_v3

Also compress the id in case of a v3 NAND flash controller (i.mx51, i.mx53)
and 16Bit buswidth.

Signed-off-by: Roman Schneider <schneider@at.festo.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: nand: omap2: Update nerrors using ecc.strength

Remove check of ecc bytes with 13, number of errors can directly update
from nand ecc strength. This will increase re-usability of the code.
Also add macro definitions BCH8_ERROR_MAX & BCH4_ERROR_MAX for better
readability and cleaner code.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: devices: elm: Add support for ELM error correction

The ELM hardware module can be used to speedup BCH 4/8/16 ECC scheme
error correction.
For now only 4 & 8 bit support is added

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
mtd: nand: omap2: Support for hardware BCH error correction.

ELM module can be used for hardware error correction of BCH 4 & 8 bit.
ELM module functionality is verified by checking the availability of
handle for ELM module in device tree. Hence supporting
1. ELM module available, BCH error correction done by ELM module. Also
support read & write page in one shot by adding custom read_page and
write_page methods. This helps in optimizing code for NAND flashes with
page size less than 4 KB.
2. If ELM module not available fall back to software BCH error
correction support.

New structure member is added to omap_nand_info
1. "is_elm_used" to know the status of whether the ELM module is used for
   error correction or not.
2. "elm_dev" device pointer to elm device on detection of ELM module.

Also being here update the device tree documentation of gpmc-nand for
adding optional property elm_id.

Note:
ECC layout uses 1 extra bytes for 512 byte of data to handle erased
pages. Extra byte programmed to zero for programmed pages. Also BCH8
requires 14 byte ecc to maintain compatibility with RBL ECC layout.
This results a common ecc layout across RBL, U-boot & Linux with BCH8.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>