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  1. 20 Jul, 2012 5 commits
    • Boaz Harrosh's avatar
      pnfs-obj: Fix __r4w_get_page when offset is beyond i_size · c999ff68
      Boaz Harrosh authored 
      It is very common for the end of the file to be unaligned on
stripe size. But since we know it's beyond file's end then
the XOR should be preformed with all zeros.

Old code used to just read zeros out of the OSD devices, which is a great
waist. But what scares me more about this situation is that, we now have
pages attached to the file's mapping that are beyond i_size. I don't
like the kind of bugs this calls for.

Fix both birds, by returning a global zero_page, if offset is beyond
i_size.

TODO:
	Change the API to ->__r4w_get_page() so a NULL can be
	returned without being considered as error, since XOR API
	treats NULL entries as zero_pages.

[Bug since 3.2. Should apply the same way to all Kernels since]
CC: Stable Tree <stable@kernel.org>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      c999ff68
    • Boaz Harrosh's avatar
      pnfs-obj: don't leak objio_state if ore_write/read fails · 9909d45a
      Boaz Harrosh authored 
      [Bug since 3.2 Kernel]
CC: Stable Tree <stable@kernel.org>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      9909d45a
    • Boaz Harrosh's avatar
      ore: Unlock r4w pages in exact reverse order of locking · 537632e0
      Boaz Harrosh authored 
      The read-4-write pages are locked in address ascending order.
But where unlocked in a way easiest for coding. Fix that,
locks should be released in opposite order of locking, .i.e
descending address order.

I have not hit this dead-lock. It was found by inspecting the
dbug print-outs. I suspect there is an higher lock at caller that
protects us, but fix it regardless.
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      537632e0
    • Boaz Harrosh's avatar
      ore: Remove support of partial IO request (NFS crash) · 62b62ad8
      Boaz Harrosh authored 
      Do to OOM situations the ore might fail to allocate all resources
needed for IO of the full request. If some progress was possible
it would proceed with a partial/short request, for the sake of
forward progress.

Since this crashes NFS-core and exofs is just fine without it just
remove this contraption, and fail.

TODO:
	Support real forward progress with some reserved allocations
	of resources, such as mem pools and/or bio_sets

[Bug since 3.2 Kernel]
CC: Stable Tree <stable@kernel.org>
CC: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      62b62ad8
    • Boaz Harrosh's avatar
      ore: Fix NFS crash by supporting any unaligned RAID IO · 9ff19309
      Boaz Harrosh authored 
      In RAID_5/6 We used to not permit an IO that it's end
byte is not stripe_size aligned and spans more than one stripe.
.i.e the caller must check if after submission the actual
transferred bytes is shorter, and would need to resubmit
a new IO with the remainder.

Exofs supports this, and NFS was supposed to support this
as well with it's short write mechanism. But late testing has
exposed a CRASH when this is used with none-RPC layout-drivers.

The change at NFS is deep and risky, in it's place the fix
at ORE to lift the limitation is actually clean and simple.
So here it is below.

The principal here is that in the case of unaligned IO on
both ends, beginning and end, we will send two read requests
one like old code, before the calculation of the first stripe,
and also a new site, before the calculation of the last stripe.
If any "boundary" is aligned or the complete IO is within a single
stripe. we do a single read like before.

The code is clean and simple by splitting the old _read_4_write
into 3 even parts:
1._read_4_write_first_stripe
2. _read_4_write_last_stripe
3. _read_4_write_execute

And calling 1+3 at the same place as before. 2+3 before last
stripe, and in the case of all in a single stripe then 1+2+3
is preformed additively.

Why did I not think of it before. Well I had a strike of
genius because I have stared at this code for 2 years, and did
not find this simple solution, til today. Not that I did not try.

This solution is much better for NFS than the previous supposedly
solution because the short write was dealt  with out-of-band after
IO_done, which would cause for a seeky IO pattern where as in here
we execute in order. At both solutions we do 2 separate reads, only
here we do it within a single IO request. (And actually combine two
writes into a single submission)

NFS/exofs code need not change since the ORE API communicates the new
shorter length on return, what will happen is that this case would not
occur anymore.

hurray!!

[Stable this is an NFS bug since 3.2 Kernel should apply cleanly]
CC: Stable Tree <stable@kernel.org>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      9ff19309
  3. 30 Jun, 2012 13 commits
  5. 29 Jun, 2012 13 commits
  7. 28 Jun, 2012 9 commits
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