Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / exofs / ore.c
diff --git a/kernel/fs/exofs/ore.c b/kernel/fs/exofs/ore.c
new file mode 100644 (file)
index 0000000..7bd8ac8
--- /dev/null
@@ -0,0 +1,1164 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <asm/div64.h>
+#include <linux/lcm.h>
+
+#include "ore_raid.h"
+
+MODULE_AUTHOR("Boaz Harrosh <ooo@electrozaur.com>");
+MODULE_DESCRIPTION("Objects Raid Engine ore.ko");
+MODULE_LICENSE("GPL");
+
+/* ore_verify_layout does a couple of things:
+ * 1. Given a minimum number of needed parameters fixes up the rest of the
+ *    members to be operatonals for the ore. The needed parameters are those
+ *    that are defined by the pnfs-objects layout STD.
+ * 2. Check to see if the current ore code actually supports these parameters
+ *    for example stripe_unit must be a multple of the system PAGE_SIZE,
+ *    and etc...
+ * 3. Cache some havily used calculations that will be needed by users.
+ */
+
+enum { BIO_MAX_PAGES_KMALLOC =
+               (PAGE_SIZE - sizeof(struct bio)) / sizeof(struct bio_vec),};
+
+int ore_verify_layout(unsigned total_comps, struct ore_layout *layout)
+{
+       u64 stripe_length;
+
+       switch (layout->raid_algorithm) {
+       case PNFS_OSD_RAID_0:
+               layout->parity = 0;
+               break;
+       case PNFS_OSD_RAID_5:
+               layout->parity = 1;
+               break;
+       case PNFS_OSD_RAID_PQ:
+               layout->parity = 2;
+               break;
+       case PNFS_OSD_RAID_4:
+       default:
+               ORE_ERR("Only RAID_0/5/6 for now received-enum=%d\n",
+                       layout->raid_algorithm);
+               return -EINVAL;
+       }
+       if (0 != (layout->stripe_unit & ~PAGE_MASK)) {
+               ORE_ERR("Stripe Unit(0x%llx)"
+                         " must be Multples of PAGE_SIZE(0x%lx)\n",
+                         _LLU(layout->stripe_unit), PAGE_SIZE);
+               return -EINVAL;
+       }
+       if (layout->group_width) {
+               if (!layout->group_depth) {
+                       ORE_ERR("group_depth == 0 && group_width != 0\n");
+                       return -EINVAL;
+               }
+               if (total_comps < (layout->group_width * layout->mirrors_p1)) {
+                       ORE_ERR("Data Map wrong, "
+                               "numdevs=%d < group_width=%d * mirrors=%d\n",
+                               total_comps, layout->group_width,
+                               layout->mirrors_p1);
+                       return -EINVAL;
+               }
+               layout->group_count = total_comps / layout->mirrors_p1 /
+                                               layout->group_width;
+       } else {
+               if (layout->group_depth) {
+                       printk(KERN_NOTICE "Warning: group_depth ignored "
+                               "group_width == 0 && group_depth == %lld\n",
+                               _LLU(layout->group_depth));
+               }
+               layout->group_width = total_comps / layout->mirrors_p1;
+               layout->group_depth = -1;
+               layout->group_count = 1;
+       }
+
+       stripe_length = (u64)layout->group_width * layout->stripe_unit;
+       if (stripe_length >= (1ULL << 32)) {
+               ORE_ERR("Stripe_length(0x%llx) >= 32bit is not supported\n",
+                       _LLU(stripe_length));
+               return -EINVAL;
+       }
+
+       layout->max_io_length =
+               (BIO_MAX_PAGES_KMALLOC * PAGE_SIZE - layout->stripe_unit) *
+                                       (layout->group_width - layout->parity);
+       if (layout->parity) {
+               unsigned stripe_length =
+                               (layout->group_width - layout->parity) *
+                               layout->stripe_unit;
+
+               layout->max_io_length /= stripe_length;
+               layout->max_io_length *= stripe_length;
+       }
+       ORE_DBGMSG("max_io_length=0x%lx\n", layout->max_io_length);
+
+       return 0;
+}
+EXPORT_SYMBOL(ore_verify_layout);
+
+static u8 *_ios_cred(struct ore_io_state *ios, unsigned index)
+{
+       return ios->oc->comps[index & ios->oc->single_comp].cred;
+}
+
+static struct osd_obj_id *_ios_obj(struct ore_io_state *ios, unsigned index)
+{
+       return &ios->oc->comps[index & ios->oc->single_comp].obj;
+}
+
+static struct osd_dev *_ios_od(struct ore_io_state *ios, unsigned index)
+{
+       ORE_DBGMSG2("oc->first_dev=%d oc->numdevs=%d i=%d oc->ods=%p\n",
+                   ios->oc->first_dev, ios->oc->numdevs, index,
+                   ios->oc->ods);
+
+       return ore_comp_dev(ios->oc, index);
+}
+
+int  _ore_get_io_state(struct ore_layout *layout,
+                       struct ore_components *oc, unsigned numdevs,
+                       unsigned sgs_per_dev, unsigned num_par_pages,
+                       struct ore_io_state **pios)
+{
+       struct ore_io_state *ios;
+       struct page **pages;
+       struct osd_sg_entry *sgilist;
+       struct __alloc_all_io_state {
+               struct ore_io_state ios;
+               struct ore_per_dev_state per_dev[numdevs];
+               union {
+                       struct osd_sg_entry sglist[sgs_per_dev * numdevs];
+                       struct page *pages[num_par_pages];
+               };
+       } *_aios;
+
+       if (likely(sizeof(*_aios) <= PAGE_SIZE)) {
+               _aios = kzalloc(sizeof(*_aios), GFP_KERNEL);
+               if (unlikely(!_aios)) {
+                       ORE_DBGMSG("Failed kzalloc bytes=%zd\n",
+                                  sizeof(*_aios));
+                       *pios = NULL;
+                       return -ENOMEM;
+               }
+               pages = num_par_pages ? _aios->pages : NULL;
+               sgilist = sgs_per_dev ? _aios->sglist : NULL;
+               ios = &_aios->ios;
+       } else {
+               struct __alloc_small_io_state {
+                       struct ore_io_state ios;
+                       struct ore_per_dev_state per_dev[numdevs];
+               } *_aio_small;
+               union __extra_part {
+                       struct osd_sg_entry sglist[sgs_per_dev * numdevs];
+                       struct page *pages[num_par_pages];
+               } *extra_part;
+
+               _aio_small = kzalloc(sizeof(*_aio_small), GFP_KERNEL);
+               if (unlikely(!_aio_small)) {
+                       ORE_DBGMSG("Failed alloc first part bytes=%zd\n",
+                                  sizeof(*_aio_small));
+                       *pios = NULL;
+                       return -ENOMEM;
+               }
+               extra_part = kzalloc(sizeof(*extra_part), GFP_KERNEL);
+               if (unlikely(!extra_part)) {
+                       ORE_DBGMSG("Failed alloc second part bytes=%zd\n",
+                                  sizeof(*extra_part));
+                       kfree(_aio_small);
+                       *pios = NULL;
+                       return -ENOMEM;
+               }
+
+               pages = num_par_pages ? extra_part->pages : NULL;
+               sgilist = sgs_per_dev ? extra_part->sglist : NULL;
+               /* In this case the per_dev[0].sgilist holds the pointer to
+                * be freed
+                */
+               ios = &_aio_small->ios;
+               ios->extra_part_alloc = true;
+       }
+
+       if (pages) {
+               ios->parity_pages = pages;
+               ios->max_par_pages = num_par_pages;
+       }
+       if (sgilist) {
+               unsigned d;
+
+               for (d = 0; d < numdevs; ++d) {
+                       ios->per_dev[d].sglist = sgilist;
+                       sgilist += sgs_per_dev;
+               }
+               ios->sgs_per_dev = sgs_per_dev;
+       }
+
+       ios->layout = layout;
+       ios->oc = oc;
+       *pios = ios;
+       return 0;
+}
+
+/* Allocate an io_state for only a single group of devices
+ *
+ * If a user needs to call ore_read/write() this version must be used becase it
+ * allocates extra stuff for striping and raid.
+ * The ore might decide to only IO less then @length bytes do to alignmets
+ * and constrains as follows:
+ * - The IO cannot cross group boundary.
+ * - In raid5/6 The end of the IO must align at end of a stripe eg.
+ *   (@offset + @length) % strip_size == 0. Or the complete range is within a
+ *   single stripe.
+ * - Memory condition only permitted a shorter IO. (A user can use @length=~0
+ *   And check the returned ios->length for max_io_size.)
+ *
+ * The caller must check returned ios->length (and/or ios->nr_pages) and
+ * re-issue these pages that fall outside of ios->length
+ */
+int  ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,
+                     bool is_reading, u64 offset, u64 length,
+                     struct ore_io_state **pios)
+{
+       struct ore_io_state *ios;
+       unsigned numdevs = layout->group_width * layout->mirrors_p1;
+       unsigned sgs_per_dev = 0, max_par_pages = 0;
+       int ret;
+
+       if (layout->parity && length) {
+               unsigned data_devs = layout->group_width - layout->parity;
+               unsigned stripe_size = layout->stripe_unit * data_devs;
+               unsigned pages_in_unit = layout->stripe_unit / PAGE_SIZE;
+               u32 remainder;
+               u64 num_stripes;
+               u64 num_raid_units;
+
+               num_stripes = div_u64_rem(length, stripe_size, &remainder);
+               if (remainder)
+                       ++num_stripes;
+
+               num_raid_units =  num_stripes * layout->parity;
+
+               if (is_reading) {
+                       /* For reads add per_dev sglist array */
+                       /* TODO: Raid 6 we need twice more. Actually:
+                       *         num_stripes / LCMdP(W,P);
+                       *         if (W%P != 0) num_stripes *= parity;
+                       */
+
+                       /* first/last seg is split */
+                       num_raid_units += layout->group_width;
+                       sgs_per_dev = div_u64(num_raid_units, data_devs) + 2;
+               } else {
+                       /* For Writes add parity pages array. */
+                       max_par_pages = num_raid_units * pages_in_unit *
+                                               sizeof(struct page *);
+               }
+       }
+
+       ret = _ore_get_io_state(layout, oc, numdevs, sgs_per_dev, max_par_pages,
+                               pios);
+       if (unlikely(ret))
+               return ret;
+
+       ios = *pios;
+       ios->reading = is_reading;
+       ios->offset = offset;
+
+       if (length) {
+               ore_calc_stripe_info(layout, offset, length, &ios->si);
+               ios->length = ios->si.length;
+               ios->nr_pages = ((ios->offset & (PAGE_SIZE - 1)) +
+                                ios->length + PAGE_SIZE - 1) / PAGE_SIZE;
+               if (layout->parity)
+                       _ore_post_alloc_raid_stuff(ios);
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL(ore_get_rw_state);
+
+/* Allocate an io_state for all the devices in the comps array
+ *
+ * This version of io_state allocation is used mostly by create/remove
+ * and trunc where we currently need all the devices. The only wastful
+ * bit is the read/write_attributes with no IO. Those sites should
+ * be converted to use ore_get_rw_state() with length=0
+ */
+int  ore_get_io_state(struct ore_layout *layout, struct ore_components *oc,
+                     struct ore_io_state **pios)
+{
+       return _ore_get_io_state(layout, oc, oc->numdevs, 0, 0, pios);
+}
+EXPORT_SYMBOL(ore_get_io_state);
+
+void ore_put_io_state(struct ore_io_state *ios)
+{
+       if (ios) {
+               unsigned i;
+
+               for (i = 0; i < ios->numdevs; i++) {
+                       struct ore_per_dev_state *per_dev = &ios->per_dev[i];
+
+                       if (per_dev->or)
+                               osd_end_request(per_dev->or);
+                       if (per_dev->bio)
+                               bio_put(per_dev->bio);
+               }
+
+               _ore_free_raid_stuff(ios);
+               kfree(ios);
+       }
+}
+EXPORT_SYMBOL(ore_put_io_state);
+
+static void _sync_done(struct ore_io_state *ios, void *p)
+{
+       struct completion *waiting = p;
+
+       complete(waiting);
+}
+
+static void _last_io(struct kref *kref)
+{
+       struct ore_io_state *ios = container_of(
+                                       kref, struct ore_io_state, kref);
+
+       ios->done(ios, ios->private);
+}
+
+static void _done_io(struct osd_request *or, void *p)
+{
+       struct ore_io_state *ios = p;
+
+       kref_put(&ios->kref, _last_io);
+}
+
+int ore_io_execute(struct ore_io_state *ios)
+{
+       DECLARE_COMPLETION_ONSTACK(wait);
+       bool sync = (ios->done == NULL);
+       int i, ret;
+
+       if (sync) {
+               ios->done = _sync_done;
+               ios->private = &wait;
+       }
+
+       for (i = 0; i < ios->numdevs; i++) {
+               struct osd_request *or = ios->per_dev[i].or;
+               if (unlikely(!or))
+                       continue;
+
+               ret = osd_finalize_request(or, 0, _ios_cred(ios, i), NULL);
+               if (unlikely(ret)) {
+                       ORE_DBGMSG("Failed to osd_finalize_request() => %d\n",
+                                    ret);
+                       return ret;
+               }
+       }
+
+       kref_init(&ios->kref);
+
+       for (i = 0; i < ios->numdevs; i++) {
+               struct osd_request *or = ios->per_dev[i].or;
+               if (unlikely(!or))
+                       continue;
+
+               kref_get(&ios->kref);
+               osd_execute_request_async(or, _done_io, ios);
+       }
+
+       kref_put(&ios->kref, _last_io);
+       ret = 0;
+
+       if (sync) {
+               wait_for_completion(&wait);
+               ret = ore_check_io(ios, NULL);
+       }
+       return ret;
+}
+
+static void _clear_bio(struct bio *bio)
+{
+       struct bio_vec *bv;
+       unsigned i;
+
+       bio_for_each_segment_all(bv, bio, i) {
+               unsigned this_count = bv->bv_len;
+
+               if (likely(PAGE_SIZE == this_count))
+                       clear_highpage(bv->bv_page);
+               else
+                       zero_user(bv->bv_page, bv->bv_offset, this_count);
+       }
+}
+
+int ore_check_io(struct ore_io_state *ios, ore_on_dev_error on_dev_error)
+{
+       enum osd_err_priority acumulated_osd_err = 0;
+       int acumulated_lin_err = 0;
+       int i;
+
+       for (i = 0; i < ios->numdevs; i++) {
+               struct osd_sense_info osi;
+               struct ore_per_dev_state *per_dev = &ios->per_dev[i];
+               struct osd_request *or = per_dev->or;
+               int ret;
+
+               if (unlikely(!or))
+                       continue;
+
+               ret = osd_req_decode_sense(or, &osi);
+               if (likely(!ret))
+                       continue;
+
+               if ((OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) &&
+                   per_dev->bio) {
+                       /* start read offset passed endof file.
+                        * Note: if we do not have bio it means read-attributes
+                        * In this case we should return error to caller.
+                        */
+                       _clear_bio(per_dev->bio);
+                       ORE_DBGMSG("start read offset passed end of file "
+                               "offset=0x%llx, length=0x%llx\n",
+                               _LLU(per_dev->offset),
+                               _LLU(per_dev->length));
+
+                       continue; /* we recovered */
+               }
+
+               if (on_dev_error) {
+                       u64 residual = ios->reading ?
+                                       or->in.residual : or->out.residual;
+                       u64 offset = (ios->offset + ios->length) - residual;
+                       unsigned dev = per_dev->dev - ios->oc->first_dev;
+                       struct ore_dev *od = ios->oc->ods[dev];
+
+                       on_dev_error(ios, od, dev, osi.osd_err_pri,
+                                    offset, residual);
+               }
+               if (osi.osd_err_pri >= acumulated_osd_err) {
+                       acumulated_osd_err = osi.osd_err_pri;
+                       acumulated_lin_err = ret;
+               }
+       }
+
+       return acumulated_lin_err;
+}
+EXPORT_SYMBOL(ore_check_io);
+
+/*
+ * L - logical offset into the file
+ *
+ * D - number of Data devices
+ *     D = group_width - parity
+ *
+ * U - The number of bytes in a stripe within a group
+ *     U =  stripe_unit * D
+ *
+ * T - The number of bytes striped within a group of component objects
+ *     (before advancing to the next group)
+ *     T = U * group_depth
+ *
+ * S - The number of bytes striped across all component objects
+ *     before the pattern repeats
+ *     S = T * group_count
+ *
+ * M - The "major" (i.e., across all components) cycle number
+ *     M = L / S
+ *
+ * G - Counts the groups from the beginning of the major cycle
+ *     G = (L - (M * S)) / T   [or (L % S) / T]
+ *
+ * H - The byte offset within the group
+ *     H = (L - (M * S)) % T   [or (L % S) % T]
+ *
+ * N - The "minor" (i.e., across the group) stripe number
+ *     N = H / U
+ *
+ * C - The component index coresponding to L
+ *
+ *     C = (H - (N * U)) / stripe_unit + G * D
+ *     [or (L % U) / stripe_unit + G * D]
+ *
+ * O - The component offset coresponding to L
+ *     O = L % stripe_unit + N * stripe_unit + M * group_depth * stripe_unit
+ *
+ * LCMdP â€“ Parity cycle: Lowest Common Multiple of group_width, parity
+ *          divide by parity
+ *     LCMdP = lcm(group_width, parity) / parity
+ *
+ * R - The parity Rotation stripe
+ *     (Note parity cycle always starts at a group's boundary)
+ *     R = N % LCMdP
+ *
+ * I = the first parity device index
+ *     I = (group_width + group_width - R*parity - parity) % group_width
+ *
+ * Craid - The component index Rotated
+ *     Craid = (group_width + C - R*parity) % group_width
+ *      (We add the group_width to avoid negative numbers modulo math)
+ */
+void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,
+                         u64 length, struct ore_striping_info *si)
+{
+       u32     stripe_unit = layout->stripe_unit;
+       u32     group_width = layout->group_width;
+       u64     group_depth = layout->group_depth;
+       u32     parity      = layout->parity;
+
+       u32     D = group_width - parity;
+       u32     U = D * stripe_unit;
+       u64     T = U * group_depth;
+       u64     S = T * layout->group_count;
+       u64     M = div64_u64(file_offset, S);
+
+       /*
+       G = (L - (M * S)) / T
+       H = (L - (M * S)) % T
+       */
+       u64     LmodS = file_offset - M * S;
+       u32     G = div64_u64(LmodS, T);
+       u64     H = LmodS - G * T;
+
+       u32     N = div_u64(H, U);
+       u32     Nlast;
+
+       /* "H - (N * U)" is just "H % U" so it's bound to u32 */
+       u32     C = (u32)(H - (N * U)) / stripe_unit + G * group_width;
+       u32 first_dev = C - C % group_width;
+
+       div_u64_rem(file_offset, stripe_unit, &si->unit_off);
+
+       si->obj_offset = si->unit_off + (N * stripe_unit) +
+                                 (M * group_depth * stripe_unit);
+       si->cur_comp = C - first_dev;
+       si->cur_pg = si->unit_off / PAGE_SIZE;
+
+       if (parity) {
+               u32 LCMdP = lcm(group_width, parity) / parity;
+               /* R     = N % LCMdP; */
+               u32 RxP   = (N % LCMdP) * parity;
+
+               si->par_dev = (group_width + group_width - parity - RxP) %
+                             group_width + first_dev;
+               si->dev = (group_width + group_width + C - RxP) %
+                         group_width + first_dev;
+               si->bytes_in_stripe = U;
+               si->first_stripe_start = M * S + G * T + N * U;
+       } else {
+               /* Make the math correct see _prepare_one_group */
+               si->par_dev = group_width;
+               si->dev = C;
+       }
+
+       si->dev *= layout->mirrors_p1;
+       si->par_dev *= layout->mirrors_p1;
+       si->offset = file_offset;
+       si->length = T - H;
+       if (si->length > length)
+               si->length = length;
+
+       Nlast = div_u64(H + si->length + U - 1, U);
+       si->maxdevUnits = Nlast - N;
+
+       si->M = M;
+}
+EXPORT_SYMBOL(ore_calc_stripe_info);
+
+int _ore_add_stripe_unit(struct ore_io_state *ios,  unsigned *cur_pg,
+                        unsigned pgbase, struct page **pages,
+                        struct ore_per_dev_state *per_dev, int cur_len)
+{
+       unsigned pg = *cur_pg;
+       struct request_queue *q =
+                       osd_request_queue(_ios_od(ios, per_dev->dev));
+       unsigned len = cur_len;
+       int ret;
+
+       if (per_dev->bio == NULL) {
+               unsigned bio_size;
+
+               if (!ios->reading) {
+                       bio_size = ios->si.maxdevUnits;
+               } else {
+                       bio_size = (ios->si.maxdevUnits + 1) *
+                            (ios->layout->group_width - ios->layout->parity) /
+                            ios->layout->group_width;
+               }
+               bio_size *= (ios->layout->stripe_unit / PAGE_SIZE);
+
+               per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
+               if (unlikely(!per_dev->bio)) {
+                       ORE_DBGMSG("Failed to allocate BIO size=%u\n",
+                                    bio_size);
+                       ret = -ENOMEM;
+                       goto out;
+               }
+       }
+
+       while (cur_len > 0) {
+               unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
+               unsigned added_len;
+
+               cur_len -= pglen;
+
+               added_len = bio_add_pc_page(q, per_dev->bio, pages[pg],
+                                           pglen, pgbase);
+               if (unlikely(pglen != added_len)) {
+                       /* If bi_vcnt == bi_max then this is a SW BUG */
+                       ORE_DBGMSG("Failed bio_add_pc_page bi_vcnt=0x%x "
+                                  "bi_max=0x%x BIO_MAX=0x%x cur_len=0x%x\n",
+                                  per_dev->bio->bi_vcnt,
+                                  per_dev->bio->bi_max_vecs,
+                                  BIO_MAX_PAGES_KMALLOC, cur_len);
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               _add_stripe_page(ios->sp2d, &ios->si, pages[pg]);
+
+               pgbase = 0;
+               ++pg;
+       }
+       BUG_ON(cur_len);
+
+       per_dev->length += len;
+       *cur_pg = pg;
+       ret = 0;
+out:   /* we fail the complete unit on an error eg don't advance
+        * per_dev->length and cur_pg. This means that we might have a bigger
+        * bio than the CDB requested length (per_dev->length). That's fine
+        * only the oposite is fatal.
+        */
+       return ret;
+}
+
+static int _add_parity_units(struct ore_io_state *ios,
+                            struct ore_striping_info *si,
+                            unsigned dev, unsigned first_dev,
+                            unsigned mirrors_p1, unsigned devs_in_group,
+                            unsigned cur_len)
+{
+       unsigned do_parity;
+       int ret = 0;
+
+       for (do_parity = ios->layout->parity; do_parity; --do_parity) {
+               struct ore_per_dev_state *per_dev;
+
+               per_dev = &ios->per_dev[dev - first_dev];
+               if (!per_dev->length && !per_dev->offset) {
+                       /* Only/always the parity unit of the first
+                        * stripe will be empty. So this is a chance to
+                        * initialize the per_dev info.
+                        */
+                       per_dev->dev = dev;
+                       per_dev->offset = si->obj_offset - si->unit_off;
+               }
+
+               ret = _ore_add_parity_unit(ios, si, per_dev, cur_len,
+                                          do_parity == 1);
+               if (unlikely(ret))
+                               break;
+
+               if (do_parity != 1) {
+                       dev = ((dev + mirrors_p1) % devs_in_group) + first_dev;
+                       si->cur_comp = (si->cur_comp + 1) %
+                                                      ios->layout->group_width;
+               }
+       }
+
+       return ret;
+}
+
+static int _prepare_for_striping(struct ore_io_state *ios)
+{
+       struct ore_striping_info *si = &ios->si;
+       unsigned stripe_unit = ios->layout->stripe_unit;
+       unsigned mirrors_p1 = ios->layout->mirrors_p1;
+       unsigned group_width = ios->layout->group_width;
+       unsigned devs_in_group = group_width * mirrors_p1;
+       unsigned dev = si->dev;
+       unsigned first_dev = dev - (dev % devs_in_group);
+       unsigned cur_pg = ios->pages_consumed;
+       u64 length = ios->length;
+       int ret = 0;
+
+       if (!ios->pages) {
+               ios->numdevs = ios->layout->mirrors_p1;
+               return 0;
+       }
+
+       BUG_ON(length > si->length);
+
+       while (length) {
+               struct ore_per_dev_state *per_dev =
+                                               &ios->per_dev[dev - first_dev];
+               unsigned cur_len, page_off = 0;
+
+               if (!per_dev->length && !per_dev->offset) {
+                       /* First time initialize the per_dev info. */
+                       per_dev->dev = dev;
+                       if (dev == si->dev) {
+                               WARN_ON(dev == si->par_dev);
+                               per_dev->offset = si->obj_offset;
+                               cur_len = stripe_unit - si->unit_off;
+                               page_off = si->unit_off & ~PAGE_MASK;
+                               BUG_ON(page_off && (page_off != ios->pgbase));
+                       } else {
+                               per_dev->offset = si->obj_offset - si->unit_off;
+                               cur_len = stripe_unit;
+                       }
+               } else {
+                       cur_len = stripe_unit;
+               }
+               if (cur_len >= length)
+                       cur_len = length;
+
+               ret = _ore_add_stripe_unit(ios, &cur_pg, page_off, ios->pages,
+                                          per_dev, cur_len);
+               if (unlikely(ret))
+                       goto out;
+
+               length -= cur_len;
+
+               dev = ((dev + mirrors_p1) % devs_in_group) + first_dev;
+               si->cur_comp = (si->cur_comp + 1) % group_width;
+               if (unlikely((dev == si->par_dev) || (!length && ios->sp2d))) {
+                       if (!length && ios->sp2d) {
+                               /* If we are writing and this is the very last
+                                * stripe. then operate on parity dev.
+                                */
+                               dev = si->par_dev;
+                               /* If last stripe operate on parity comp */
+                               si->cur_comp = group_width - ios->layout->parity;
+                       }
+
+                       /* In writes cur_len just means if it's the
+                        * last one. See _ore_add_parity_unit.
+                        */
+                       ret = _add_parity_units(ios, si, dev, first_dev,
+                                               mirrors_p1, devs_in_group,
+                                               ios->sp2d ? length : cur_len);
+                       if (unlikely(ret))
+                                       goto out;
+
+                       /* Rotate next par_dev backwards with wraping */
+                       si->par_dev = (devs_in_group + si->par_dev -
+                                      ios->layout->parity * mirrors_p1) %
+                                     devs_in_group + first_dev;
+                       /* Next stripe, start fresh */
+                       si->cur_comp = 0;
+                       si->cur_pg = 0;
+                       si->obj_offset += cur_len;
+                       si->unit_off = 0;
+               }
+       }
+out:
+       ios->numdevs = devs_in_group;
+       ios->pages_consumed = cur_pg;
+       return ret;
+}
+
+int ore_create(struct ore_io_state *ios)
+{
+       int i, ret;
+
+       for (i = 0; i < ios->oc->numdevs; i++) {
+               struct osd_request *or;
+
+               or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
+               if (unlikely(!or)) {
+                       ORE_ERR("%s: osd_start_request failed\n", __func__);
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               ios->per_dev[i].or = or;
+               ios->numdevs++;
+
+               osd_req_create_object(or, _ios_obj(ios, i));
+       }
+       ret = ore_io_execute(ios);
+
+out:
+       return ret;
+}
+EXPORT_SYMBOL(ore_create);
+
+int ore_remove(struct ore_io_state *ios)
+{
+       int i, ret;
+
+       for (i = 0; i < ios->oc->numdevs; i++) {
+               struct osd_request *or;
+
+               or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
+               if (unlikely(!or)) {
+                       ORE_ERR("%s: osd_start_request failed\n", __func__);
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               ios->per_dev[i].or = or;
+               ios->numdevs++;
+
+               osd_req_remove_object(or, _ios_obj(ios, i));
+       }
+       ret = ore_io_execute(ios);
+
+out:
+       return ret;
+}
+EXPORT_SYMBOL(ore_remove);
+
+static int _write_mirror(struct ore_io_state *ios, int cur_comp)
+{
+       struct ore_per_dev_state *master_dev = &ios->per_dev[cur_comp];
+       unsigned dev = ios->per_dev[cur_comp].dev;
+       unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
+       int ret = 0;
+
+       if (ios->pages && !master_dev->length)
+               return 0; /* Just an empty slot */
+
+       for (; cur_comp < last_comp; ++cur_comp, ++dev) {
+               struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
+               struct osd_request *or;
+
+               or = osd_start_request(_ios_od(ios, dev), GFP_KERNEL);
+               if (unlikely(!or)) {
+                       ORE_ERR("%s: osd_start_request failed\n", __func__);
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               per_dev->or = or;
+
+               if (ios->pages) {
+                       struct bio *bio;
+
+                       if (per_dev != master_dev) {
+                               bio = bio_clone_kmalloc(master_dev->bio,
+                                                       GFP_KERNEL);
+                               if (unlikely(!bio)) {
+                                       ORE_DBGMSG(
+                                             "Failed to allocate BIO size=%u\n",
+                                             master_dev->bio->bi_max_vecs);
+                                       ret = -ENOMEM;
+                                       goto out;
+                               }
+
+                               bio->bi_bdev = NULL;
+                               bio->bi_next = NULL;
+                               per_dev->offset = master_dev->offset;
+                               per_dev->length = master_dev->length;
+                               per_dev->bio =  bio;
+                               per_dev->dev = dev;
+                       } else {
+                               bio = master_dev->bio;
+                               /* FIXME: bio_set_dir() */
+                               bio->bi_rw |= REQ_WRITE;
+                       }
+
+                       osd_req_write(or, _ios_obj(ios, cur_comp),
+                                     per_dev->offset, bio, per_dev->length);
+                       ORE_DBGMSG("write(0x%llx) offset=0x%llx "
+                                     "length=0x%llx dev=%d\n",
+                                    _LLU(_ios_obj(ios, cur_comp)->id),
+                                    _LLU(per_dev->offset),
+                                    _LLU(per_dev->length), dev);
+               } else if (ios->kern_buff) {
+                       per_dev->offset = ios->si.obj_offset;
+                       per_dev->dev = ios->si.dev + dev;
+
+                       /* no cross device without page array */
+                       BUG_ON((ios->layout->group_width > 1) &&
+                              (ios->si.unit_off + ios->length >
+                               ios->layout->stripe_unit));
+
+                       ret = osd_req_write_kern(or, _ios_obj(ios, cur_comp),
+                                                per_dev->offset,
+                                                ios->kern_buff, ios->length);
+                       if (unlikely(ret))
+                               goto out;
+                       ORE_DBGMSG2("write_kern(0x%llx) offset=0x%llx "
+                                     "length=0x%llx dev=%d\n",
+                                    _LLU(_ios_obj(ios, cur_comp)->id),
+                                    _LLU(per_dev->offset),
+                                    _LLU(ios->length), per_dev->dev);
+               } else {
+                       osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
+                       ORE_DBGMSG2("obj(0x%llx) set_attributes=%d dev=%d\n",
+                                    _LLU(_ios_obj(ios, cur_comp)->id),
+                                    ios->out_attr_len, dev);
+               }
+
+               if (ios->out_attr)
+                       osd_req_add_set_attr_list(or, ios->out_attr,
+                                                 ios->out_attr_len);
+
+               if (ios->in_attr)
+                       osd_req_add_get_attr_list(or, ios->in_attr,
+                                                 ios->in_attr_len);
+       }
+
+out:
+       return ret;
+}
+
+int ore_write(struct ore_io_state *ios)
+{
+       int i;
+       int ret;
+
+       if (unlikely(ios->sp2d && !ios->r4w)) {
+               /* A library is attempting a RAID-write without providing
+                * a pages lock interface.
+                */
+               WARN_ON_ONCE(1);
+               return -ENOTSUPP;
+       }
+
+       ret = _prepare_for_striping(ios);
+       if (unlikely(ret))
+               return ret;
+
+       for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
+               ret = _write_mirror(ios, i);
+               if (unlikely(ret))
+                       return ret;
+       }
+
+       ret = ore_io_execute(ios);
+       return ret;
+}
+EXPORT_SYMBOL(ore_write);
+
+int _ore_read_mirror(struct ore_io_state *ios, unsigned cur_comp)
+{
+       struct osd_request *or;
+       struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
+       struct osd_obj_id *obj = _ios_obj(ios, cur_comp);
+       unsigned first_dev = (unsigned)obj->id;
+
+       if (ios->pages && !per_dev->length)
+               return 0; /* Just an empty slot */
+
+       first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
+       or = osd_start_request(_ios_od(ios, first_dev), GFP_KERNEL);
+       if (unlikely(!or)) {
+               ORE_ERR("%s: osd_start_request failed\n", __func__);
+               return -ENOMEM;
+       }
+       per_dev->or = or;
+
+       if (ios->pages) {
+               if (per_dev->cur_sg) {
+                       /* finalize the last sg_entry */
+                       _ore_add_sg_seg(per_dev, 0, false);
+                       if (unlikely(!per_dev->cur_sg))
+                               return 0; /* Skip parity only device */
+
+                       osd_req_read_sg(or, obj, per_dev->bio,
+                                       per_dev->sglist, per_dev->cur_sg);
+               } else {
+                       /* The no raid case */
+                       osd_req_read(or, obj, per_dev->offset,
+                                    per_dev->bio, per_dev->length);
+               }
+
+               ORE_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
+                            " dev=%d sg_len=%d\n", _LLU(obj->id),
+                            _LLU(per_dev->offset), _LLU(per_dev->length),
+                            first_dev, per_dev->cur_sg);
+       } else {
+               BUG_ON(ios->kern_buff);
+
+               osd_req_get_attributes(or, obj);
+               ORE_DBGMSG2("obj(0x%llx) get_attributes=%d dev=%d\n",
+                             _LLU(obj->id),
+                             ios->in_attr_len, first_dev);
+       }
+       if (ios->out_attr)
+               osd_req_add_set_attr_list(or, ios->out_attr, ios->out_attr_len);
+
+       if (ios->in_attr)
+               osd_req_add_get_attr_list(or, ios->in_attr, ios->in_attr_len);
+
+       return 0;
+}
+
+int ore_read(struct ore_io_state *ios)
+{
+       int i;
+       int ret;
+
+       ret = _prepare_for_striping(ios);
+       if (unlikely(ret))
+               return ret;
+
+       for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
+               ret = _ore_read_mirror(ios, i);
+               if (unlikely(ret))
+                       return ret;
+       }
+
+       ret = ore_io_execute(ios);
+       return ret;
+}
+EXPORT_SYMBOL(ore_read);
+
+int extract_attr_from_ios(struct ore_io_state *ios, struct osd_attr *attr)
+{
+       struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
+       void *iter = NULL;
+       int nelem;
+
+       do {
+               nelem = 1;
+               osd_req_decode_get_attr_list(ios->per_dev[0].or,
+                                            &cur_attr, &nelem, &iter);
+               if ((cur_attr.attr_page == attr->attr_page) &&
+                   (cur_attr.attr_id == attr->attr_id)) {
+                       attr->len = cur_attr.len;
+                       attr->val_ptr = cur_attr.val_ptr;
+                       return 0;
+               }
+       } while (iter);
+
+       return -EIO;
+}
+EXPORT_SYMBOL(extract_attr_from_ios);
+
+static int _truncate_mirrors(struct ore_io_state *ios, unsigned cur_comp,
+                            struct osd_attr *attr)
+{
+       int last_comp = cur_comp + ios->layout->mirrors_p1;
+
+       for (; cur_comp < last_comp; ++cur_comp) {
+               struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
+               struct osd_request *or;
+
+               or = osd_start_request(_ios_od(ios, cur_comp), GFP_KERNEL);
+               if (unlikely(!or)) {
+                       ORE_ERR("%s: osd_start_request failed\n", __func__);
+                       return -ENOMEM;
+               }
+               per_dev->or = or;
+
+               osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
+               osd_req_add_set_attr_list(or, attr, 1);
+       }
+
+       return 0;
+}
+
+struct _trunc_info {
+       struct ore_striping_info si;
+       u64 prev_group_obj_off;
+       u64 next_group_obj_off;
+
+       unsigned first_group_dev;
+       unsigned nex_group_dev;
+};
+
+static void _calc_trunk_info(struct ore_layout *layout, u64 file_offset,
+                            struct _trunc_info *ti)
+{
+       unsigned stripe_unit = layout->stripe_unit;
+
+       ore_calc_stripe_info(layout, file_offset, 0, &ti->si);
+
+       ti->prev_group_obj_off = ti->si.M * stripe_unit;
+       ti->next_group_obj_off = ti->si.M ? (ti->si.M - 1) * stripe_unit : 0;
+
+       ti->first_group_dev = ti->si.dev - (ti->si.dev % layout->group_width);
+       ti->nex_group_dev = ti->first_group_dev + layout->group_width;
+}
+
+int ore_truncate(struct ore_layout *layout, struct ore_components *oc,
+                  u64 size)
+{
+       struct ore_io_state *ios;
+       struct exofs_trunc_attr {
+               struct osd_attr attr;
+               __be64 newsize;
+       } *size_attrs;
+       struct _trunc_info ti;
+       int i, ret;
+
+       ret = ore_get_io_state(layout, oc, &ios);
+       if (unlikely(ret))
+               return ret;
+
+       _calc_trunk_info(ios->layout, size, &ti);
+
+       size_attrs = kcalloc(ios->oc->numdevs, sizeof(*size_attrs),
+                            GFP_KERNEL);
+       if (unlikely(!size_attrs)) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       ios->numdevs = ios->oc->numdevs;
+
+       for (i = 0; i < ios->numdevs; ++i) {
+               struct exofs_trunc_attr *size_attr = &size_attrs[i];
+               u64 obj_size;
+
+               if (i < ti.first_group_dev)
+                       obj_size = ti.prev_group_obj_off;
+               else if (i >= ti.nex_group_dev)
+                       obj_size = ti.next_group_obj_off;
+               else if (i < ti.si.dev) /* dev within this group */
+                       obj_size = ti.si.obj_offset +
+                                     ios->layout->stripe_unit - ti.si.unit_off;
+               else if (i == ti.si.dev)
+                       obj_size = ti.si.obj_offset;
+               else /* i > ti.dev */
+                       obj_size = ti.si.obj_offset - ti.si.unit_off;
+
+               size_attr->newsize = cpu_to_be64(obj_size);
+               size_attr->attr = g_attr_logical_length;
+               size_attr->attr.val_ptr = &size_attr->newsize;
+
+               ORE_DBGMSG2("trunc(0x%llx) obj_offset=0x%llx dev=%d\n",
+                            _LLU(oc->comps->obj.id), _LLU(obj_size), i);
+               ret = _truncate_mirrors(ios, i * ios->layout->mirrors_p1,
+                                       &size_attr->attr);
+               if (unlikely(ret))
+                       goto out;
+       }
+       ret = ore_io_execute(ios);
+
+out:
+       kfree(size_attrs);
+       ore_put_io_state(ios);
+       return ret;
+}
+EXPORT_SYMBOL(ore_truncate);
+
+const struct osd_attr g_attr_logical_length = ATTR_DEF(
+       OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
+EXPORT_SYMBOL(g_attr_logical_length);