Memory conditions and max_bio constraints might cause us to
not comply to the full length of the requested IO. Instead of
failing the complete IO we can issue a shorter read/write and
report how much was actually executed in the ios->length
member.
All users must check ios->length at IO_done or upon return of
ore_read/write and re-issue the reminder of the bytes. Because
other wise there is no error returned like before.
This is part of the effort to support the pnfs-obj layout driver.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Move the check and preparation of the ios->kern_buff case to
later inside _write_mirror().
Since read was never used with ios->kern_buff its support is removed
instead of fixed.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Now that each ore_io_state covers only a single raid group.
A single striping_info math is needed. Embed one inside
ore_io_state to cache the calculation results and eliminate
an extra call.
Also the outer _prepare_for_striping is removed since it does nothing.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Usually a single IO is confined to one group of devices
(group_width) and at the boundary of a raid group it can
spill into a second group. Current code would allocate a
full device_table size array at each io_state so it can
comply to requests that span two groups. Needless to say
that is very wasteful, specially when device_table count
can get very large (hundreds even thousands), while a
group_width is usually 8 or 10.
* Change ore API to trim on IO that spans two raid groups.
The user passes offset+length to ore_get_rw_state, the
ore might trim on that length if spanning a group boundary.
The user must check ios->length or ios->nrpages to see
how much IO will be preformed. It is the responsibility
of the user to re-issue the reminder of the IO.
* Modify exofs To copy spilled pages on to the next IO.
This means one last kick is needed after all coalescing
of pages is done.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
In the pNFS obj-LD the device table at the layout level needs
to point to a device_cache node, where it is possible and likely
that many layouts will point to the same device-nodes.
In Exofs we have a more orderly structure where we have a single
array of devices that repeats twice for a round-robin view of the
device table
This patch moves to a model that can be used by the pNFS obj-LD
where struct ore_components holds an array of ore_dev-pointers.
(ore_dev is newly defined and contains a struct osd_dev *od
member)
Each pointer in the array of pointers will point to a bigger
user-defined dev_struct. That can be accessed by use of the
container_of macro.
In Exofs an __alloc_dev_table() function allocates the
ore_dev-pointers array as well as an exofs_dev array, in one
allocation and does the addresses dance to set everything pointing
correctly. It still keeps the double allocation trick for the
inodes round-robin view of the table.
The device table is always allocated dynamically, also for the
single device case. So it is unconditionally freed at umount.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
The struct ore_striping_info will be used later in other
structures. And ore_calc_stripe_info as well. Rename them
make struct ore_striping_info public. ore_calc_stripe_info
is still static, will be made public on first use.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
ore_components already has a comps member so this leads
to things like comps->comps which is annoying. the name oc
was already used in new code. So rename all old usage of
ore_components comps => ore_components oc.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
This quiets the sparse noise:
warning: symbol '_calc_trunk_info' was not declared. Should it be static?
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Export everything from ore need exporting. Change Kbuild and Kconfig
to build ore.ko as an independent module. Import ore from exofs
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
ORE stands for "Objects Raid Engine"
This patch is a mechanical rename of everything that was in ios.c
and its API declaration to an ore.c and an osd_ore.h header. The ore
engine will later be used by the pnfs objects layout driver.
* File ios.c => ore.c
* Declaration of types and API are moved from exofs.h to a new
osd_ore.h
* All used types are prefixed by ore_ from their exofs_ name.
* Shift includes from exofs.h to osd_ore.h so osd_ore.h is
independent, include it from exofs.h.
Other than a pure rename there are no other changes. Next patch
will move the ore into it's own module and will export the API
to be used by exofs and later the layout driver
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Boaz Harrosh