Add TuxOnIce support

1 files changed, 1126 insertions, 0 deletions

diff --git a/kernel/power/tuxonice_bio_chains.c b/kernel/power/tuxonice_bio_chains.c
new file mode 100644
index 000000000..086a5527d
--- /dev/null
+++ b/kernel/power/tuxonice_bio_chains.c
@@ -0,0 +1,1126 @@
+/*
+ * kernel/power/tuxonice_bio_devinfo.c
+ *
+ * Copyright (C) 2009-2015 Nigel Cunningham (nigel at nigelcunningham com au)
+ *
+ * Distributed under GPLv2.
+ *
+ */
+
+#include <linux/mm_types.h>
+#include "tuxonice_bio.h"
+#include "tuxonice_bio_internal.h"
+#include "tuxonice_alloc.h"
+#include "tuxonice_ui.h"
+#include "tuxonice.h"
+#include "tuxonice_io.h"
+
+static struct toi_bdev_info *prio_chain_head;
+static int num_chains;
+
+/* Pointer to current entry being loaded/saved. */
+struct toi_extent_iterate_state toi_writer_posn;
+
+#define metadata_size (sizeof(struct toi_bdev_info) - \
+                offsetof(struct toi_bdev_info, uuid))
+
+/*
+ * After section 0 (header) comes 2 => next_section[0] = 2
+ */
+static int next_section[3] = { 2, 3, 1 };
+
+/**
+ * dump_block_chains - print the contents of the bdev info array.
+ **/
+void dump_block_chains(void)
+{
+        int i = 0;
+        int j;
+        struct toi_bdev_info *cur_chain = prio_chain_head;
+
+        while (cur_chain) {
+                struct hibernate_extent *this = cur_chain->blocks.first;
+
+                printk(KERN_DEBUG "Chain %d (prio %d):", i, cur_chain->prio);
+
+                while (this) {
+                        printk(KERN_CONT " [%lu-%lu]%s", this->start,
+                                        this->end, this->next ? "," : "");
+                        this = this->next;
+                }
+
+                printk("\n");
+                cur_chain = cur_chain->next;
+                i++;
+        }
+
+        printk(KERN_DEBUG "Saved states:\n");
+        for (i = 0; i < 4; i++) {
+                printk(KERN_DEBUG "Slot %d: Chain %d.\n",
+                        i, toi_writer_posn.saved_chain_number[i]);
+
+                cur_chain = prio_chain_head;
+                j = 0;
+                while (cur_chain) {
+                        printk(KERN_DEBUG " Chain %d: Extent %d. Offset %lu.\n",
+                                        j, cur_chain->saved_state[i].extent_num,
+                                        cur_chain->saved_state[i].offset);
+                        cur_chain = cur_chain->next;
+                        j++;
+                }
+                printk(KERN_CONT "\n");
+        }
+}
+
+/**
+ *
+ **/
+static void toi_extent_chain_next(void)
+{
+        struct toi_bdev_info *this = toi_writer_posn.current_chain;
+
+        if (!this->blocks.current_extent)
+                return;
+
+        if (this->blocks.current_offset == this->blocks.current_extent->end) {
+                if (this->blocks.current_extent->next) {
+                        this->blocks.current_extent =
+                                this->blocks.current_extent->next;
+                        this->blocks.current_offset =
+                                this->blocks.current_extent->start;
+                } else {
+                        this->blocks.current_extent = NULL;
+                        this->blocks.current_offset = 0;
+                }
+        } else
+                this->blocks.current_offset++;
+}
+
+/**
+ *
+ */
+
+static struct toi_bdev_info *__find_next_chain_same_prio(void)
+{
+        struct toi_bdev_info *start_chain = toi_writer_posn.current_chain;
+        struct toi_bdev_info *this = start_chain;
+        int orig_prio = this->prio;
+
+        do {
+                this = this->next;
+
+                if (!this)
+                        this = prio_chain_head;
+
+                /* Back on original chain? Use it again. */
+                if (this == start_chain)
+                        return start_chain;
+
+        } while (!this->blocks.current_extent || this->prio != orig_prio);
+
+        return this;
+}
+
+static void find_next_chain(void)
+{
+        struct toi_bdev_info *this;
+
+        this = __find_next_chain_same_prio();
+
+        /*
+         * If we didn't get another chain of the same priority that we
+         * can use, look for the next priority.
+         */
+        while (this && !this->blocks.current_extent)
+                this = this->next;
+
+        toi_writer_posn.current_chain = this;
+}
+
+/**
+ * toi_extent_state_next - go to the next extent
+ * @blocks: The number of values to progress.
+ * @stripe_mode: Whether to spread usage across all chains.
+ *
+ * Given a state, progress to the next valid entry. We may begin in an
+ * invalid state, as we do when invoked after extent_state_goto_start below.
+ *
+ * When using compression and expected_compression > 0, we let the image size
+ * be larger than storage, so we can validly run out of data to return.
+ **/
+static unsigned long toi_extent_state_next(int blocks, int current_stream)
+{
+        int i;
+
+        if (!toi_writer_posn.current_chain)
+                return -ENOSPC;
+
+        /* Assume chains always have lengths that are multiples of @blocks */
+        for (i = 0; i < blocks; i++)
+                toi_extent_chain_next();
+
+        /* The header stream is not striped */
+        if (current_stream ||
+            !toi_writer_posn.current_chain->blocks.current_extent)
+                find_next_chain();
+
+        return  toi_writer_posn.current_chain ? 0 : -ENOSPC;
+}
+
+static void toi_insert_chain_in_prio_list(struct toi_bdev_info *this)
+{
+        struct toi_bdev_info **prev_ptr;
+        struct toi_bdev_info *cur;
+
+        /* Loop through the existing chain, finding where to insert it */
+        prev_ptr = &prio_chain_head;
+        cur = prio_chain_head;
+
+        while (cur && cur->prio >= this->prio) {
+                prev_ptr = &cur->next;
+                cur = cur->next;
+        }
+
+        this->next = *prev_ptr;
+        *prev_ptr = this;
+
+        this = prio_chain_head;
+        while (this)
+                this = this->next;
+        num_chains++;
+}
+
+/**
+ * toi_extent_state_goto_start - reinitialize an extent chain iterator
+ * @state:        Iterator to reinitialize
+ **/
+void toi_extent_state_goto_start(void)
+{
+        struct toi_bdev_info *this = prio_chain_head;
+
+        while (this) {
+                toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                        "Setting current extent to %p.", this->blocks.first);
+                this->blocks.current_extent = this->blocks.first;
+                if (this->blocks.current_extent) {
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                        "Setting current offset to %lu.",
+                                        this->blocks.current_extent->start);
+                        this->blocks.current_offset =
+                                this->blocks.current_extent->start;
+                }
+
+                this = this->next;
+        }
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Setting current chain to %p.",
+                        prio_chain_head);
+        toi_writer_posn.current_chain = prio_chain_head;
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Leaving extent state goto start.");
+}
+
+/**
+ * toi_extent_state_save - save state of the iterator
+ * @state:                Current state of the chain
+ * @saved_state:        Iterator to populate
+ *
+ * Given a state and a struct hibernate_extent_state_store, save the current
+ * position in a format that can be used with relocated chains (at
+ * resume time).
+ **/
+void toi_extent_state_save(int slot)
+{
+        struct toi_bdev_info *cur_chain = prio_chain_head;
+        struct hibernate_extent *extent;
+        struct hibernate_extent_saved_state *chain_state;
+        int i = 0;
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "toi_extent_state_save, slot %d.",
+                        slot);
+
+        if (!toi_writer_posn.current_chain) {
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "No current chain => "
+                                "chain_num = -1.");
+                toi_writer_posn.saved_chain_number[slot] = -1;
+                return;
+        }
+
+        while (cur_chain) {
+                i++;
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "Saving chain %d (%p) "
+                                "state, slot %d.", i, cur_chain, slot);
+
+                chain_state = &cur_chain->saved_state[slot];
+
+                chain_state->offset = cur_chain->blocks.current_offset;
+
+                if (toi_writer_posn.current_chain == cur_chain) {
+                        toi_writer_posn.saved_chain_number[slot] = i;
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0, "This is the chain "
+                                        "we were on => chain_num is %d.", i);
+                }
+
+                if (!cur_chain->blocks.current_extent) {
+                        chain_state->extent_num = 0;
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0, "No current extent "
+                                        "for this chain => extent_num %d is 0.",
+                                        i);
+                        cur_chain = cur_chain->next;
+                        continue;
+                }
+
+                extent = cur_chain->blocks.first;
+                chain_state->extent_num = 1;
+
+                while (extent != cur_chain->blocks.current_extent) {
+                        chain_state->extent_num++;
+                        extent = extent->next;
+                }
+
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "extent num %d is %d.", i,
+                                chain_state->extent_num);
+
+                cur_chain = cur_chain->next;
+        }
+        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                        "Completed saving extent state slot %d.", slot);
+}
+
+/**
+ * toi_extent_state_restore - restore the position saved by extent_state_save
+ * @state:                State to populate
+ * @saved_state:        Iterator saved to restore
+ **/
+void toi_extent_state_restore(int slot)
+{
+        int i = 0;
+        struct toi_bdev_info *cur_chain = prio_chain_head;
+        struct hibernate_extent_saved_state *chain_state;
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                        "toi_extent_state_restore - slot %d.", slot);
+
+        if (toi_writer_posn.saved_chain_number[slot] == -1) {
+                toi_writer_posn.current_chain = NULL;
+                return;
+        }
+
+        while (cur_chain) {
+                int posn;
+                int j;
+                i++;
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "Restoring chain %d (%p) "
+                                "state, slot %d.", i, cur_chain, slot);
+
+                chain_state = &cur_chain->saved_state[slot];
+
+                posn = chain_state->extent_num;
+
+                cur_chain->blocks.current_extent = cur_chain->blocks.first;
+                cur_chain->blocks.current_offset = chain_state->offset;
+
+                if (i == toi_writer_posn.saved_chain_number[slot]) {
+                        toi_writer_posn.current_chain = cur_chain;
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                        "Found current chain.");
+                }
+
+                for (j = 0; j < 4; j++)
+                        if (i == toi_writer_posn.saved_chain_number[j]) {
+                                toi_writer_posn.saved_chain_ptr[j] = cur_chain;
+                                toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                        "Found saved chain ptr %d (%p) (offset"
+                                        " %d).", j, cur_chain,
+                                        cur_chain->saved_state[j].offset);
+                        }
+
+                if (posn) {
+                        while (--posn)
+                                cur_chain->blocks.current_extent =
+                                        cur_chain->blocks.current_extent->next;
+                } else
+                        cur_chain->blocks.current_extent = NULL;
+
+                cur_chain = cur_chain->next;
+        }
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Done.");
+        if (test_action_state(TOI_LOGALL))
+                dump_block_chains();
+}
+
+/*
+ * Storage needed
+ *
+ * Returns amount of space in the image header required
+ * for the chain data. This ignores the links between
+ * pages, which we factor in when allocating the space.
+ */
+int toi_bio_devinfo_storage_needed(void)
+{
+        int result = sizeof(num_chains);
+        struct toi_bdev_info *chain = prio_chain_head;
+
+        while (chain) {
+                result += metadata_size;
+
+                /* Chain size */
+                result += sizeof(int);
+
+                /* Extents */
+                result += (2 * sizeof(unsigned long) *
+                        chain->blocks.num_extents);
+
+                chain = chain->next;
+        }
+
+        result += 4 * sizeof(int);
+        return result;
+}
+
+static unsigned long chain_pages_used(struct toi_bdev_info *chain)
+{
+        struct hibernate_extent *this = chain->blocks.first;
+        struct hibernate_extent_saved_state *state = &chain->saved_state[3];
+        unsigned long size = 0;
+        int extent_idx = 1;
+
+        if (!state->extent_num) {
+                if (!this)
+                        return 0;
+                else
+                        return chain->blocks.size;
+        }
+
+        while (extent_idx < state->extent_num) {
+                size += (this->end - this->start + 1);
+                this = this->next;
+                extent_idx++;
+        }
+
+        /* We didn't use the one we're sitting on, so don't count it */
+        return size + state->offset - this->start;
+}
+
+void toi_bio_free_unused_storage_chain(struct toi_bdev_info *chain)
+{
+    unsigned long used = chain_pages_used(chain);
+
+    /* Free the storage */
+    unsigned long first_freed = 0;
+
+    if (chain->allocator->bio_allocator_ops->free_unused_storage)
+        first_freed = chain->allocator->bio_allocator_ops->free_unused_storage(chain, used);
+
+    printk(KERN_EMERG "Used %ld blocks in this chain. First extent freed is %lx.\n", used, first_freed);
+
+    /* Adjust / free the extents. */
+    toi_put_extent_chain_from(&chain->blocks, first_freed);
+
+    {
+        struct hibernate_extent *this = chain->blocks.first;
+        while (this) {
+            printk("Extent %lx-%lx.\n", this->start, this->end);
+            this = this->next;
+        }
+    }
+}
+
+/**
+ * toi_serialise_extent_chain - write a chain in the image
+ * @chain:        Chain to write.
+ **/
+static int toi_serialise_extent_chain(struct toi_bdev_info *chain)
+{
+        struct hibernate_extent *this;
+        int ret;
+        int i = 1;
+
+        chain->pages_used = chain_pages_used(chain);
+
+        if (test_action_state(TOI_LOGALL))
+                dump_block_chains();
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Serialising chain (dev_t %lx).",
+                        chain->dev_t);
+        /* Device info -  dev_t, prio, bmap_shift, blocks per page, positions */
+        ret = toiActiveAllocator->rw_header_chunk(WRITE, &toi_blockwriter_ops,
+                        (char *) &chain->uuid, metadata_size);
+        if (ret)
+                return ret;
+
+        /* Num extents */
+        ret = toiActiveAllocator->rw_header_chunk(WRITE, &toi_blockwriter_ops,
+                        (char *) &chain->blocks.num_extents, sizeof(int));
+        if (ret)
+                return ret;
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "%d extents.",
+                        chain->blocks.num_extents);
+
+        this = chain->blocks.first;
+        while (this) {
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "Extent %d.", i);
+                ret = toiActiveAllocator->rw_header_chunk(WRITE,
+                                &toi_blockwriter_ops,
+                                (char *) this, 2 * sizeof(this->start));
+                if (ret)
+                        return ret;
+                this = this->next;
+                i++;
+        }
+
+        return ret;
+}
+
+int toi_serialise_extent_chains(void)
+{
+        struct toi_bdev_info *this = prio_chain_head;
+        int result;
+
+        /* Write the number of chains */
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Write number of chains (%d)",
+                        num_chains);
+        result = toiActiveAllocator->rw_header_chunk(WRITE,
+                        &toi_blockwriter_ops, (char *) &num_chains,
+                        sizeof(int));
+        if (result)
+                return result;
+
+        /* Then the chains themselves */
+        while (this) {
+                result = toi_serialise_extent_chain(this);
+                if (result)
+                        return result;
+                this = this->next;
+        }
+
+        /*
+         * Finally, the chain we should be on at the start of each
+         * section.
+         */
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Saved chain numbers.");
+        result = toiActiveAllocator->rw_header_chunk(WRITE,
+                        &toi_blockwriter_ops,
+                        (char *) &toi_writer_posn.saved_chain_number[0],
+                        4 * sizeof(int));
+
+        return result;
+}
+
+int toi_register_storage_chain(struct toi_bdev_info *new)
+{
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Inserting chain %p into list.",
+                        new);
+        toi_insert_chain_in_prio_list(new);
+        return 0;
+}
+
+static void free_bdev_info(struct toi_bdev_info *chain)
+{
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Free chain %p.", chain);
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, " - Block extents.");
+        toi_put_extent_chain(&chain->blocks);
+
+        /*
+         * The allocator may need to do more than just free the chains
+         * (swap_free, for example). Don't call from boot kernel.
+         */
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, " - Allocator extents.");
+        if (chain->allocator)
+                chain->allocator->bio_allocator_ops->free_storage(chain);
+
+        /*
+         * Dropping out of reading atomic copy? Need to undo
+         * toi_open_by_devnum.
+         */
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, " - Bdev.");
+        if (chain->bdev && !IS_ERR(chain->bdev) &&
+                        chain->bdev != resume_block_device &&
+                        chain->bdev != header_block_device &&
+                        test_toi_state(TOI_TRYING_TO_RESUME))
+                toi_close_bdev(chain->bdev);
+
+        /* Poison */
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, " - Struct.");
+        toi_kfree(39, chain, sizeof(*chain));
+
+        if (prio_chain_head == chain)
+                prio_chain_head = NULL;
+
+        num_chains--;
+}
+
+void free_all_bdev_info(void)
+{
+        struct toi_bdev_info *this = prio_chain_head;
+
+        while (this) {
+                struct toi_bdev_info *next = this->next;
+                free_bdev_info(this);
+                this = next;
+        }
+
+        memset((char *) &toi_writer_posn, 0, sizeof(toi_writer_posn));
+        prio_chain_head = NULL;
+}
+
+static void set_up_start_position(void)
+{
+        toi_writer_posn.current_chain = prio_chain_head;
+        go_next_page(0, 0);
+}
+
+/**
+ * toi_load_extent_chain - read back a chain saved in the image
+ * @chain:        Chain to load
+ *
+ * The linked list of extents is reconstructed from the disk. chain will point
+ * to the first entry.
+ **/
+int toi_load_extent_chain(int index, int *num_loaded)
+{
+        struct toi_bdev_info *chain = toi_kzalloc(39,
+                        sizeof(struct toi_bdev_info), GFP_ATOMIC);
+        struct hibernate_extent *this, *last = NULL;
+        int i, ret;
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Loading extent chain %d.", index);
+        /* Get dev_t, prio, bmap_shift, blocks per page, positions */
+        ret = toiActiveAllocator->rw_header_chunk_noreadahead(READ, NULL,
+                        (char *) &chain->uuid, metadata_size);
+
+        if (ret) {
+                printk(KERN_ERR "Failed to read the size of extent chain.\n");
+                toi_kfree(39, chain, sizeof(*chain));
+                return 1;
+        }
+
+        toi_bkd.pages_used[index] = chain->pages_used;
+
+        ret = toiActiveAllocator->rw_header_chunk_noreadahead(READ, NULL,
+                        (char *) &chain->blocks.num_extents, sizeof(int));
+        if (ret) {
+                printk(KERN_ERR "Failed to read the size of extent chain.\n");
+                toi_kfree(39, chain, sizeof(*chain));
+                return 1;
+        }
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "%d extents.",
+                        chain->blocks.num_extents);
+
+        for (i = 0; i < chain->blocks.num_extents; i++) {
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "Extent %d.", i + 1);
+
+                this = toi_kzalloc(2, sizeof(struct hibernate_extent),
+                                TOI_ATOMIC_GFP);
+                if (!this) {
+                        printk(KERN_INFO "Failed to allocate a new extent.\n");
+                        free_bdev_info(chain);
+                        return -ENOMEM;
+                }
+                this->next = NULL;
+                /* Get the next page */
+                ret = toiActiveAllocator->rw_header_chunk_noreadahead(READ,
+                                NULL, (char *) this, 2 * sizeof(this->start));
+                if (ret) {
+                        printk(KERN_INFO "Failed to read an extent.\n");
+                        toi_kfree(2, this, sizeof(struct hibernate_extent));
+                        free_bdev_info(chain);
+                        return 1;
+                }
+
+                if (last)
+                        last->next = this;
+                else {
+                        char b1[32], b2[32], b3[32];
+                        /*
+                         * Open the bdev
+                         */
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                "Chain dev_t is %s. Resume dev t is %s. Header"
+                                " bdev_t is %s.\n",
+                                format_dev_t(b1, chain->dev_t),
+                                format_dev_t(b2, resume_dev_t),
+                                format_dev_t(b3, toi_sig_data->header_dev_t));
+
+                        if (chain->dev_t == resume_dev_t)
+                                chain->bdev = resume_block_device;
+                        else if (chain->dev_t == toi_sig_data->header_dev_t)
+                                chain->bdev = header_block_device;
+                        else {
+                                chain->bdev = toi_open_bdev(chain->uuid,
+                                                chain->dev_t, 1);
+                                if (IS_ERR(chain->bdev)) {
+                                        free_bdev_info(chain);
+                                        return -ENODEV;
+                                }
+                        }
+
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Chain bmap shift "
+                                        "is %d and blocks per page is %d.",
+                                        chain->bmap_shift,
+                                        chain->blocks_per_page);
+
+                        chain->blocks.first = this;
+
+                        /*
+                         * Couldn't do this earlier, but can't do
+                         * goto_start now - we may have already used blocks
+                         * in the first chain.
+                         */
+                        chain->blocks.current_extent = this;
+                        chain->blocks.current_offset = this->start;
+
+                        /*
+                         * Can't wait until we've read the whole chain
+                         * before we insert it in the list. We might need
+                         * this chain to read the next page in the header
+                         */
+                        toi_insert_chain_in_prio_list(chain);
+                }
+
+                /*
+                 * We have to wait until 2 extents are loaded before setting up
+                 * properly because if the first extent has only one page, we
+                 * will need to put the position on the second extent. Sounds
+                 * obvious, but it wasn't!
+                 */
+                (*num_loaded)++;
+                if ((*num_loaded) == 2)
+                        set_up_start_position();
+                last = this;
+        }
+
+        /*
+         * Shouldn't get empty chains, but it's not impossible. Link them in so
+         * they get freed properly later.
+         */
+        if (!chain->blocks.num_extents)
+                toi_insert_chain_in_prio_list(chain);
+
+        if (!chain->blocks.current_extent) {
+                chain->blocks.current_extent = chain->blocks.first;
+                if (chain->blocks.current_extent)
+                        chain->blocks.current_offset =
+                                chain->blocks.current_extent->start;
+        }
+        return 0;
+}
+
+int toi_load_extent_chains(void)
+{
+        int result;
+        int to_load;
+        int i;
+        int extents_loaded = 0;
+
+        result = toiActiveAllocator->rw_header_chunk_noreadahead(READ, NULL,
+                        (char *) &to_load,
+                        sizeof(int));
+        if (result)
+                return result;
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "%d chains to read.", to_load);
+
+        for (i = 0; i < to_load; i++) {
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, " >> Loading chain %d/%d.",
+                                i, to_load);
+                result = toi_load_extent_chain(i, &extents_loaded);
+                if (result)
+                        return result;
+        }
+
+        /* If we never got to a second extent, we still need to do this. */
+        if (extents_loaded == 1)
+                set_up_start_position();
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Save chain numbers.");
+        result = toiActiveAllocator->rw_header_chunk_noreadahead(READ,
+                        &toi_blockwriter_ops,
+                        (char *) &toi_writer_posn.saved_chain_number[0],
+                        4 * sizeof(int));
+
+        return result;
+}
+
+static int toi_end_of_stream(int writing, int section_barrier)
+{
+        struct toi_bdev_info *cur_chain = toi_writer_posn.current_chain;
+        int compare_to = next_section[current_stream];
+        struct toi_bdev_info *compare_chain =
+                toi_writer_posn.saved_chain_ptr[compare_to];
+        int compare_offset = compare_chain ?
+                compare_chain->saved_state[compare_to].offset : 0;
+
+        if (!section_barrier)
+                return 0;
+
+        if (!cur_chain)
+                return 1;
+
+        if (cur_chain == compare_chain &&
+            cur_chain->blocks.current_offset == compare_offset) {
+                if (writing) {
+                        if (!current_stream) {
+                                debug_broken_header();
+                                return 1;
+                        }
+                } else {
+                        more_readahead = 0;
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                        "Reached the end of stream %d "
+                                        "(not an error).", current_stream);
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+
+/**
+ * go_next_page - skip blocks to the start of the next page
+ * @writing: Whether we're reading or writing the image.
+ *
+ * Go forward one page.
+ **/
+int go_next_page(int writing, int section_barrier)
+{
+        struct toi_bdev_info *cur_chain = toi_writer_posn.current_chain;
+        int max = cur_chain ? cur_chain->blocks_per_page : 1;
+
+        /* Nope. Go foward a page - or maybe two. Don't stripe the header,
+         * so that bad fragmentation doesn't put the extent data containing
+         * the location of the second page out of the first header page.
+         */
+        if (toi_extent_state_next(max, current_stream)) {
+                /* Don't complain if readahead falls off the end */
+                if (writing && section_barrier) {
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Extent state eof. "
+                                "Expected compression ratio too optimistic?");
+                        if (test_action_state(TOI_LOGALL))
+                                dump_block_chains();
+                }
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "Ran out of extents to "
+                                "read/write. (Not necessarily a fatal error.");
+                return -ENOSPC;
+        }
+
+        return 0;
+}
+
+int devices_of_same_priority(struct toi_bdev_info *this)
+{
+        struct toi_bdev_info *check = prio_chain_head;
+        int i = 0;
+
+        while (check) {
+                if (check->prio == this->prio)
+                        i++;
+                check = check->next;
+        }
+
+        return i;
+}
+
+/**
+ * toi_bio_rw_page - do i/o on the next disk page in the image
+ * @writing: Whether reading or writing.
+ * @page: Page to do i/o on.
+ * @is_readahead: Whether we're doing readahead
+ * @free_group: The group used in allocating the page
+ *
+ * Submit a page for reading or writing, possibly readahead.
+ * Pass the group used in allocating the page as well, as it should
+ * be freed on completion of the bio if we're writing the page.
+ **/
+int toi_bio_rw_page(int writing, struct page *page,
+                int is_readahead, int free_group)
+{
+        int result = toi_end_of_stream(writing, 1);
+        struct toi_bdev_info *dev_info = toi_writer_posn.current_chain;
+
+        if (result) {
+                if (writing)
+                        abort_hibernate(TOI_INSUFFICIENT_STORAGE,
+                                "Insufficient storage for your image.");
+                else
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Seeking to "
+                                "read/write another page when stream has "
+                                "ended.");
+                return -ENOSPC;
+        }
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                        "%s %lx:%ld",
+                        writing ? "Write" : "Read",
+                        dev_info->dev_t, dev_info->blocks.current_offset);
+
+        result = toi_do_io(writing, dev_info->bdev,
+                dev_info->blocks.current_offset << dev_info->bmap_shift,
+                page, is_readahead, 0, free_group);
+
+        /* Ignore the result here - will check end of stream if come in again */
+        go_next_page(writing, 1);
+
+        if (result)
+                printk(KERN_ERR "toi_do_io returned %d.\n", result);
+        return result;
+}
+
+dev_t get_header_dev_t(void)
+{
+        return prio_chain_head->dev_t;
+}
+
+struct block_device *get_header_bdev(void)
+{
+        return prio_chain_head->bdev;
+}
+
+unsigned long get_headerblock(void)
+{
+        return prio_chain_head->blocks.first->start <<
+                prio_chain_head->bmap_shift;
+}
+
+int get_main_pool_phys_params(void)
+{
+        struct toi_bdev_info *this = prio_chain_head;
+        int result;
+
+        while (this) {
+                result = this->allocator->bio_allocator_ops->bmap(this);
+                if (result)
+                        return result;
+                this = this->next;
+        }
+
+        return 0;
+}
+
+static int apply_header_reservation(void)
+{
+        int i;
+
+        if (!header_pages_reserved) {
+                toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                "No header pages reserved at the moment.");
+                return 0;
+        }
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Applying header reservation.");
+
+        /* Apply header space reservation */
+        toi_extent_state_goto_start();
+
+        for (i = 0; i < header_pages_reserved; i++)
+                if (go_next_page(1, 0))
+                        return -ENOSPC;
+
+        /* The end of header pages will be the start of pageset 2 */
+        toi_extent_state_save(2);
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                        "Finished applying header reservation.");
+        return 0;
+}
+
+static int toi_bio_register_storage(void)
+{
+        int result = 0;
+        struct toi_module_ops *this_module;
+
+        list_for_each_entry(this_module, &toi_modules, module_list) {
+                if (!this_module->enabled ||
+                    this_module->type != BIO_ALLOCATOR_MODULE)
+                        continue;
+                toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                "Registering storage from %s.",
+                                this_module->name);
+                result = this_module->bio_allocator_ops->register_storage();
+                if (result)
+                        break;
+        }
+
+        return result;
+}
+
+void toi_bio_free_unused_storage(void)
+{
+    struct toi_bdev_info *this = prio_chain_head;
+
+    while (this) {
+        toi_bio_free_unused_storage_chain(this);
+        this = this->next;
+    }
+}
+
+int toi_bio_allocate_storage(unsigned long request)
+{
+        struct toi_bdev_info *chain = prio_chain_head;
+        unsigned long to_get = request;
+        unsigned long extra_pages, needed;
+        int no_free = 0;
+
+        if (!chain) {
+                int result = toi_bio_register_storage();
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, "toi_bio_allocate_storage: "
+                        "Registering storage.");
+                if (result)
+                        return 0;
+                chain = prio_chain_head;
+                if (!chain) {
+                        printk("TuxOnIce: No storage was registered.\n");
+                        return 0;
+                }
+        }
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "toi_bio_allocate_storage: "
+                        "Request is %lu pages.", request);
+        extra_pages = DIV_ROUND_UP(request * (sizeof(unsigned long)
+                               + sizeof(int)), PAGE_SIZE);
+        needed = request + extra_pages + header_pages_reserved;
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Adding %lu extra pages and %lu "
+                        "for header => %lu.",
+                        extra_pages, header_pages_reserved, needed);
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Already allocated %lu pages.",
+                        raw_pages_allocd);
+
+        to_get = needed > raw_pages_allocd ? needed - raw_pages_allocd : 0;
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Need to get %lu pages.", to_get);
+
+        if (!to_get)
+                return apply_header_reservation();
+
+        while (to_get && chain) {
+                int num_group = devices_of_same_priority(chain);
+                int divisor = num_group - no_free;
+                int i;
+                unsigned long portion = DIV_ROUND_UP(to_get, divisor);
+                unsigned long got = 0;
+                unsigned long got_this_round = 0;
+                struct toi_bdev_info *top = chain;
+
+                toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                " Start of loop. To get is %lu. Divisor is %d.",
+                                to_get, divisor);
+                no_free = 0;
+
+                /*
+                 * We're aiming to spread the allocated storage as evenly
+                 * as possible, but we also want to get all the storage we
+                 * can off this priority.
+                 */
+                for (i = 0; i < num_group; i++) {
+                        struct toi_bio_allocator_ops *ops =
+                                chain->allocator->bio_allocator_ops;
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                        " Asking for %lu pages from chain %p.",
+                                        portion, chain);
+                        got = ops->allocate_storage(chain, portion);
+                        toi_message(TOI_BIO, TOI_VERBOSE, 0,
+                                        " Got %lu pages from allocator %p.",
+                                        got, chain);
+                        if (!got)
+                                no_free++;
+                        got_this_round += got;
+                        chain = chain->next;
+                }
+                toi_message(TOI_BIO, TOI_VERBOSE, 0, " Loop finished. Got a "
+                                "total of %lu pages from %d allocators.",
+                                got_this_round, divisor - no_free);
+
+                raw_pages_allocd += got_this_round;
+                to_get = needed > raw_pages_allocd ? needed - raw_pages_allocd :
+                        0;
+
+                /*
+                 * If we got anything from chains of this priority and we
+                 * still have storage to allocate, go over this priority
+                 * again.
+                 */
+                if (got_this_round && to_get)
+                        chain = top;
+                else
+                        no_free = 0;
+        }
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Finished allocating. Calling "
+                        "get_main_pool_phys_params");
+        /* Now let swap allocator bmap the pages */
+        get_main_pool_phys_params();
+
+        toi_message(TOI_BIO, TOI_VERBOSE, 0, "Done. Reserving header.");
+        return apply_header_reservation();
+}
+
+void toi_bio_chains_post_atomic(struct toi_boot_kernel_data *bkd)
+{
+        int i = 0;
+        struct toi_bdev_info *cur_chain = prio_chain_head;
+
+        while (cur_chain) {
+                cur_chain->pages_used = bkd->pages_used[i];
+                cur_chain = cur_chain->next;
+                i++;
+        }
+}
+
+int toi_bio_chains_debug_info(char *buffer, int size)
+{
+        /* Show what we actually used */
+        struct toi_bdev_info *cur_chain = prio_chain_head;
+        int len = 0;
+
+        while (cur_chain) {
+                len += scnprintf(buffer + len, size - len, "  Used %lu pages "
+                                "from %s.\n", cur_chain->pages_used,
+                                cur_chain->name);
+                cur_chain = cur_chain->next;
+        }
+
+        return len;
+}
+
+void toi_bio_store_inc_image_ptr(struct toi_incremental_image_pointer *ptr)
+{
+    struct toi_bdev_info *this = toi_writer_posn.current_chain,
+                         *cmp = prio_chain_head;
+
+    ptr->save.chain = 1;
+    while (this != cmp) {
+        ptr->save.chain++;
+        cmp = cmp->next;
+    }
+    ptr->save.block = this->blocks.current_offset;
+
+    /* Save the raw info internally for quicker access when updating pointers */
+    ptr->bdev = this->bdev;
+    ptr->block = this->blocks.current_offset << this->bmap_shift;
+}
+
+void toi_bio_restore_inc_image_ptr(struct toi_incremental_image_pointer *ptr)
+{
+    int i = ptr->save.chain - 1;
+    struct toi_bdev_info *this;
+    struct hibernate_extent *hib;
+
+    /* Find chain by stored index */
+    this = prio_chain_head;
+    while (i) {
+        this = this->next;
+        i--;
+    }
+    toi_writer_posn.current_chain = this;
+
+    /* Restore block */
+    this->blocks.current_offset = ptr->save.block;
+
+    /* Find current offset from block number */
+    hib = this->blocks.first;
+
+    while (hib->start > ptr->save.block) {
+        hib = hib->next;
+    }
+
+    this->blocks.last_touched = this->blocks.current_extent = hib;
+}