1. 19 Oct, 2014 1 commit
  2. 23 Jan, 2014 1 commit
    • Boaz Harrosh's avatar
      ore: Fix wrong math in allocation of per device BIO · aad560b7
      Boaz Harrosh authored
      At IO preparation we calculate the max pages at each device and
      allocate a BIO per device of that size. The calculation was wrong
      on some unaligned corner cases offset/length combination and would
      make prepare return with -ENOMEM. This would be bad for pnfs-objects
      that would in that case IO through MDS. And fatal for exofs were it
      would fail writes with EIO.
      
      Fix it by doing the proper math, that will work in all cases. (I
      ran a test with all possible offset/length combinations this time
      round).
      
      Also when reading we do not need to allocate for the parity units
      since we jump over them.
      
      Also lower the max_io_length to take into account the parity pages
      so not to allocate BIOs bigger than PAGE_SIZE
      
      CC: Stable Kernel <stable@vger.kernel.org>
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      aad560b7
  3. 04 Mar, 2012 1 commit
    • Paul Gortmaker's avatar
      BUG: headers with BUG/BUG_ON etc. need linux/bug.h · 187f1882
      Paul Gortmaker authored
      If a header file is making use of BUG, BUG_ON, BUILD_BUG_ON, or any
      other BUG variant in a static inline (i.e. not in a #define) then
      that header really should be including <linux/bug.h> and not just
      expecting it to be implicitly present.
      
      We can make this change risk-free, since if the files using these
      headers didn't have exposure to linux/bug.h already, they would have
      been causing compile failures/warnings.
      Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
      187f1882
  4. 24 Oct, 2011 3 commits
    • Boaz Harrosh's avatar
      ore: RAID5 Write · 769ba8d9
      Boaz Harrosh authored
      This is finally the RAID5 Write support.
      
      The bigger part of this patch is not the XOR engine itself, But the
      read4write logic, which is a complete mini prepare_for_striping
      reading engine that can read scattered pages of a stripe into cache
      so it can be used for XOR calculation. That is, if the write was not
      stripe aligned.
      
      The main algorithm behind the XOR engine is the 2 dimensional array:
      	struct __stripe_pages_2d.
      A drawing might save 1000 words
      ---
      
      __stripe_pages_2d
             |
       n = pages_in_stripe_unit;
       w = group_width - parity;
             |                            pages array presented to the XOR lib
             |                                                |
             V                                                |
       __1_page_stripe[0].pages --> [c0][c1]..[cw][c_par] <---|
             |                                                |
       __1_page_stripe[1].pages --> [c0][c1]..[cw][c_par] <---
             |
      ...    |                         ...
             |
       __1_page_stripe[n].pages --> [c0][c1]..[cw][c_par]
                                     ^
                                     |
                 data added columns first then row
      
      ---
      The pages are put on this array columns first. .i.e:
      	p0-of-c0, p1-of-c0, ... pn-of-c0, p0-of-c1, ...
      So we are doing a corner turn of the pages.
      
      Note that pages will zigzag down and left. but are put sequentially
      in growing order. So when the time comes to XOR the stripe, only the
      beginning and end of the array need be checked. We scan the array
      and any NULL spot will be field by pages-to-be-read.
      
      The FS that wants to support RAID5 needs to supply an
      operations-vector that searches a given page in cache, and specifies
      if the page is uptodate or need reading. All these pages to be read
      are put on a slave ore_io_state and synchronously read. All the pages
      of a stripe are read in one IO, using the scatter gather mechanism.
      
      In write we constrain our IO to only be incomplete on a single
      stripe. Meaning either the complete IO is within a single stripe so
      we might have pages to read from both beginning  or end of the
      strip. Or we have some reading to do at beginning but end at strip
      boundary. The left over pages are pushed to the next IO by the API
      already established by previous work, where an IO offset/length
      combination presented to the ORE might get the length truncated and
      the user must re-submit the leftover pages. (Both exofs and NFS
      support this)
      
      But any ORE user should make it's best effort to align it's IO
      before hand and avoid complications. A cached ore_layout->stripe_size
      member can be used for that calculation. (NOTE: that ORE demands
      that stripe_size may not be bigger then 32bit)
      
      What else? Well read it and tell me.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      769ba8d9
    • Boaz Harrosh's avatar
      ore: RAID5 read · a1fec1db
      Boaz Harrosh authored
      This patch introduces the first stage of RAID5 support
      mainly the skip-over-raid-units when reading. For
      writes it inserts BLANK units, into where XOR blocks
      should be calculated and written to.
      
      It introduces the new "general raid maths", and the main
      additional parameters and components needed for raid5.
      
      Since at this stage it could corrupt future version that
      actually do support raid5. The enablement of raid5
      mounting and setting of parity-count > 0 is disabled. So
      the raid5 code will never be used. Mounting of raid5 is
      only enabled later once the basic XOR write is also in.
      But if the patch "enable RAID5" is applied this code has
      been tested to be able to properly read raid5 volumes
      and is according to standard.
      
      Also it has been tested that the new maths still properly
      supports RAID0 and grouping code just as before.
      (BTW: I have found more bugs in the pnfs-obj RAID math
       fixed here)
      
      The ore.c file is getting too big, so new ore_raid.[hc]
      files are added that will include the special raid stuff
      that are not used in striping and mirrors. In future write
      support these will get bigger.
      When adding the ore_raid.c to Kbuild file I was forced to
      rename ore.ko to libore.ko. Is it possible to keep source
      file, say ore.c and module file ore.ko the same even if there
      are multiple files inside ore.ko?
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      a1fec1db
    • Boaz Harrosh's avatar
      ore: Make ore_calc_stripe_info EXPORT_SYMBOL · 611d7a5d
      Boaz Harrosh authored
      ore_calc_stripe_info is needed by exofs::export.c
      for the layout calculations. Make it exportable
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      611d7a5d
  5. 14 Oct, 2011 4 commits
    • Boaz Harrosh's avatar
      ore/exofs: Change ore_check_io API · 4b46c9f5
      Boaz Harrosh authored
      Current ore_check_io API receives a residual
      pointer, to report partial IO. But it is actually
      not used, because in a multiple devices IO there
      is never a linearity in the IO failure.
      
      On the other hand if every failing device is reported
      through a received callback measures can be taken to
      handle only failed devices. One at a time.
      
      This will also be needed by the objects-layout-driver
      for it's error reporting facility.
      
      Exofs is not currently using the new information and
      keeps the old behaviour of failing the complete IO in
      case of an error. (No partial completion)
      
      TODO: Use an ore_check_io callback to set_page_error only
      the failing pages. And re-dirty write pages.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      4b46c9f5
    • Boaz Harrosh's avatar
      ore/exofs: Define new ore_verify_layout · 5a51c0c7
      Boaz Harrosh authored
      All users of the ore will need to check if current code
      supports the given layout. For example RAID5/6 is not
      currently supported.
      
      So move all the checks from exofs/super.c to a new
      ore_verify_layout() to be used by ore users.
      
      Note that any new layout should be passed through the
      ore_verify_layout() because the ore engine will prepare
      and verify some internal members of ore_layout, and
      assumes it's called.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      5a51c0c7
    • Boaz Harrosh's avatar
      ore: Support for partial component table · 3bd98568
      Boaz Harrosh authored
      Users like the objlayout-driver would like to only pass
      a partial device table that covers the IO in question.
      For example exofs divides the file into raid-group-sized
      chunks and only serves group_width number of devices at
      a time.
      
      The partiality is communicated by setting
      ore_componets->first_dev and the array covers all logical
      devices from oc->first_dev upto (oc->first_dev + oc->numdevs)
      
      The ore_comp_dev() API receives a logical device index
      and returns the actual present device in the table.
      An out-of-range dev_index will BUG.
      
      Logical device index is the theoretical device index as if
      all the devices of a file are present. .i.e:
      	total_devs = group_width * mirror_p1 * group_count
      	0 <= dev_index < total_devs
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      3bd98568
    • Boaz Harrosh's avatar
      ore: cleanup: Embed an ore_striping_info inside ore_io_state · 98260754
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      98260754
  6. 04 Oct, 2011 1 commit
    • Boaz Harrosh's avatar
      ore/exofs: Change the type of the devices array (API change) · d866d875
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      d866d875
  7. 03 Oct, 2011 3 commits
  8. 06 Aug, 2011 1 commit
    • Boaz Harrosh's avatar
      exofs: Rename raid engine from exofs/ios.c => ore · 8ff660ab
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      8ff660ab