Btrfs: Split the extent_map code into two parts
There is now extent_map for mapping offsets in the file to disk and
extent_io for state tracking, IO submission and extent_bufers.
The new extent_map code shifts from [start,end] pairs to [start,len], and
pushes the locking out into the caller. This allows a few performance
optimizations and is easier to use.
A number of extent_map usage bugs were fixed, mostly with failing
to remove extent_map entries when changing the file.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
new file mode 100644
index 0000000..15cc158
--- /dev/null
+++ b/fs/btrfs/extent_io.c
@@ -0,0 +1,3089 @@
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/bio.h>
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/pagemap.h>
+#include <linux/page-flags.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/swap.h>
+#include <linux/version.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include "extent_io.h"
+#include "extent_map.h"
+
+/* temporary define until extent_map moves out of btrfs */
+struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
+ unsigned long extra_flags,
+ void (*ctor)(void *, struct kmem_cache *,
+ unsigned long));
+
+static struct kmem_cache *extent_state_cache;
+static struct kmem_cache *extent_buffer_cache;
+
+static LIST_HEAD(buffers);
+static LIST_HEAD(states);
+
+static spinlock_t state_lock = SPIN_LOCK_UNLOCKED;
+#define BUFFER_LRU_MAX 64
+
+struct tree_entry {
+ u64 start;
+ u64 end;
+ int in_tree;
+ struct rb_node rb_node;
+};
+
+struct extent_page_data {
+ struct bio *bio;
+ struct extent_io_tree *tree;
+ get_extent_t *get_extent;
+};
+
+int __init extent_io_init(void)
+{
+ extent_state_cache = btrfs_cache_create("extent_state",
+ sizeof(struct extent_state), 0,
+ NULL);
+ if (!extent_state_cache)
+ return -ENOMEM;
+
+ extent_buffer_cache = btrfs_cache_create("extent_buffers",
+ sizeof(struct extent_buffer), 0,
+ NULL);
+ if (!extent_buffer_cache)
+ goto free_state_cache;
+ return 0;
+
+free_state_cache:
+ kmem_cache_destroy(extent_state_cache);
+ return -ENOMEM;
+}
+
+void extent_io_exit(void)
+{
+ struct extent_state *state;
+
+ while (!list_empty(&states)) {
+ state = list_entry(states.next, struct extent_state, list);
+ printk("state leak: start %Lu end %Lu state %lu in tree %d refs %d\n", state->start, state->end, state->state, state->in_tree, atomic_read(&state->refs));
+ list_del(&state->list);
+ kmem_cache_free(extent_state_cache, state);
+
+ }
+
+ if (extent_state_cache)
+ kmem_cache_destroy(extent_state_cache);
+ if (extent_buffer_cache)
+ kmem_cache_destroy(extent_buffer_cache);
+}
+
+void extent_io_tree_init(struct extent_io_tree *tree,
+ struct address_space *mapping, gfp_t mask)
+{
+ tree->state.rb_node = NULL;
+ tree->ops = NULL;
+ tree->dirty_bytes = 0;
+ rwlock_init(&tree->lock);
+ spin_lock_init(&tree->lru_lock);
+ tree->mapping = mapping;
+ INIT_LIST_HEAD(&tree->buffer_lru);
+ tree->lru_size = 0;
+}
+EXPORT_SYMBOL(extent_io_tree_init);
+
+void extent_io_tree_empty_lru(struct extent_io_tree *tree)
+{
+ struct extent_buffer *eb;
+ while(!list_empty(&tree->buffer_lru)) {
+ eb = list_entry(tree->buffer_lru.next, struct extent_buffer,
+ lru);
+ list_del_init(&eb->lru);
+ free_extent_buffer(eb);
+ }
+}
+EXPORT_SYMBOL(extent_io_tree_empty_lru);
+
+struct extent_state *alloc_extent_state(gfp_t mask)
+{
+ struct extent_state *state;
+ unsigned long flags;
+
+ state = kmem_cache_alloc(extent_state_cache, mask);
+ if (!state || IS_ERR(state))
+ return state;
+ state->state = 0;
+ state->in_tree = 0;
+ state->private = 0;
+
+ spin_lock_irqsave(&state_lock, flags);
+ list_add(&state->list, &states);
+ spin_unlock_irqrestore(&state_lock, flags);
+
+ atomic_set(&state->refs, 1);
+ init_waitqueue_head(&state->wq);
+ return state;
+}
+EXPORT_SYMBOL(alloc_extent_state);
+
+void free_extent_state(struct extent_state *state)
+{
+ unsigned long flags;
+ if (!state)
+ return;
+ if (atomic_dec_and_test(&state->refs)) {
+ WARN_ON(state->in_tree);
+ spin_lock_irqsave(&state_lock, flags);
+ list_del(&state->list);
+ spin_unlock_irqrestore(&state_lock, flags);
+ kmem_cache_free(extent_state_cache, state);
+ }
+}
+EXPORT_SYMBOL(free_extent_state);
+
+static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
+ struct rb_node *node)
+{
+ struct rb_node ** p = &root->rb_node;
+ struct rb_node * parent = NULL;
+ struct tree_entry *entry;
+
+ while(*p) {
+ parent = *p;
+ entry = rb_entry(parent, struct tree_entry, rb_node);
+
+ if (offset < entry->start)
+ p = &(*p)->rb_left;
+ else if (offset > entry->end)
+ p = &(*p)->rb_right;
+ else
+ return parent;
+ }
+
+ entry = rb_entry(node, struct tree_entry, rb_node);
+ entry->in_tree = 1;
+ rb_link_node(node, parent, p);
+ rb_insert_color(node, root);
+ return NULL;
+}
+
+static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
+ struct rb_node **prev_ret,
+ struct rb_node **next_ret)
+{
+ struct rb_node * n = root->rb_node;
+ struct rb_node *prev = NULL;
+ struct rb_node *orig_prev = NULL;
+ struct tree_entry *entry;
+ struct tree_entry *prev_entry = NULL;
+
+ while(n) {
+ entry = rb_entry(n, struct tree_entry, rb_node);
+ prev = n;
+ prev_entry = entry;
+
+ if (offset < entry->start)
+ n = n->rb_left;
+ else if (offset > entry->end)
+ n = n->rb_right;
+ else
+ return n;
+ }
+
+ if (prev_ret) {
+ orig_prev = prev;
+ while(prev && offset > prev_entry->end) {
+ prev = rb_next(prev);
+ prev_entry = rb_entry(prev, struct tree_entry, rb_node);
+ }
+ *prev_ret = prev;
+ prev = orig_prev;
+ }
+
+ if (next_ret) {
+ prev_entry = rb_entry(prev, struct tree_entry, rb_node);
+ while(prev && offset < prev_entry->start) {
+ prev = rb_prev(prev);
+ prev_entry = rb_entry(prev, struct tree_entry, rb_node);
+ }
+ *next_ret = prev;
+ }
+ return NULL;
+}
+
+static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
+{
+ struct rb_node *prev;
+ struct rb_node *ret;
+ ret = __tree_search(root, offset, &prev, NULL);
+ if (!ret)
+ return prev;
+ return ret;
+}
+
+/*
+ * utility function to look for merge candidates inside a given range.
+ * Any extents with matching state are merged together into a single
+ * extent in the tree. Extents with EXTENT_IO in their state field
+ * are not merged because the end_io handlers need to be able to do
+ * operations on them without sleeping (or doing allocations/splits).
+ *
+ * This should be called with the tree lock held.
+ */
+static int merge_state(struct extent_io_tree *tree,
+ struct extent_state *state)
+{
+ struct extent_state *other;
+ struct rb_node *other_node;
+
+ if (state->state & EXTENT_IOBITS)
+ return 0;
+
+ other_node = rb_prev(&state->rb_node);
+ if (other_node) {
+ other = rb_entry(other_node, struct extent_state, rb_node);
+ if (other->end == state->start - 1 &&
+ other->state == state->state) {
+ state->start = other->start;
+ other->in_tree = 0;
+ rb_erase(&other->rb_node, &tree->state);
+ free_extent_state(other);
+ }
+ }
+ other_node = rb_next(&state->rb_node);
+ if (other_node) {
+ other = rb_entry(other_node, struct extent_state, rb_node);
+ if (other->start == state->end + 1 &&
+ other->state == state->state) {
+ other->start = state->start;
+ state->in_tree = 0;
+ rb_erase(&state->rb_node, &tree->state);
+ free_extent_state(state);
+ }
+ }
+ return 0;
+}
+
+/*
+ * insert an extent_state struct into the tree. 'bits' are set on the
+ * struct before it is inserted.
+ *
+ * This may return -EEXIST if the extent is already there, in which case the
+ * state struct is freed.
+ *
+ * The tree lock is not taken internally. This is a utility function and
+ * probably isn't what you want to call (see set/clear_extent_bit).
+ */
+static int insert_state(struct extent_io_tree *tree,
+ struct extent_state *state, u64 start, u64 end,
+ int bits)
+{
+ struct rb_node *node;
+
+ if (end < start) {
+ printk("end < start %Lu %Lu\n", end, start);
+ WARN_ON(1);
+ }
+ if (bits & EXTENT_DIRTY)
+ tree->dirty_bytes += end - start + 1;
+ state->state |= bits;
+ state->start = start;
+ state->end = end;
+ node = tree_insert(&tree->state, end, &state->rb_node);
+ if (node) {
+ struct extent_state *found;
+ found = rb_entry(node, struct extent_state, rb_node);
+ printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
+ free_extent_state(state);
+ return -EEXIST;
+ }
+ merge_state(tree, state);
+ return 0;
+}
+
+/*
+ * split a given extent state struct in two, inserting the preallocated
+ * struct 'prealloc' as the newly created second half. 'split' indicates an
+ * offset inside 'orig' where it should be split.
+ *
+ * Before calling,
+ * the tree has 'orig' at [orig->start, orig->end]. After calling, there
+ * are two extent state structs in the tree:
+ * prealloc: [orig->start, split - 1]
+ * orig: [ split, orig->end ]
+ *
+ * The tree locks are not taken by this function. They need to be held
+ * by the caller.
+ */
+static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
+ struct extent_state *prealloc, u64 split)
+{
+ struct rb_node *node;
+ prealloc->start = orig->start;
+ prealloc->end = split - 1;
+ prealloc->state = orig->state;
+ orig->start = split;
+
+ node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
+ if (node) {
+ struct extent_state *found;
+ found = rb_entry(node, struct extent_state, rb_node);
+ printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
+ free_extent_state(prealloc);
+ return -EEXIST;
+ }
+ return 0;
+}
+
+/*
+ * utility function to clear some bits in an extent state struct.
+ * it will optionally wake up any one waiting on this state (wake == 1), or
+ * forcibly remove the state from the tree (delete == 1).
+ *
+ * If no bits are set on the state struct after clearing things, the
+ * struct is freed and removed from the tree
+ */
+static int clear_state_bit(struct extent_io_tree *tree,
+ struct extent_state *state, int bits, int wake,
+ int delete)
+{
+ int ret = state->state & bits;
+
+ if ((bits & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
+ u64 range = state->end - state->start + 1;
+ WARN_ON(range > tree->dirty_bytes);
+ tree->dirty_bytes -= range;
+ }
+ state->state &= ~bits;
+ if (wake)
+ wake_up(&state->wq);
+ if (delete || state->state == 0) {
+ if (state->in_tree) {
+ rb_erase(&state->rb_node, &tree->state);
+ state->in_tree = 0;
+ free_extent_state(state);
+ } else {
+ WARN_ON(1);
+ }
+ } else {
+ merge_state(tree, state);
+ }
+ return ret;
+}
+
+/*
+ * clear some bits on a range in the tree. This may require splitting
+ * or inserting elements in the tree, so the gfp mask is used to
+ * indicate which allocations or sleeping are allowed.
+ *
+ * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
+ * the given range from the tree regardless of state (ie for truncate).
+ *
+ * the range [start, end] is inclusive.
+ *
+ * This takes the tree lock, and returns < 0 on error, > 0 if any of the
+ * bits were already set, or zero if none of the bits were already set.
+ */
+int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ int bits, int wake, int delete, gfp_t mask)
+{
+ struct extent_state *state;
+ struct extent_state *prealloc = NULL;
+ struct rb_node *node;
+ unsigned long flags;
+ int err;
+ int set = 0;
+
+again:
+ if (!prealloc && (mask & __GFP_WAIT)) {
+ prealloc = alloc_extent_state(mask);
+ if (!prealloc)
+ return -ENOMEM;
+ }
+
+ write_lock_irqsave(&tree->lock, flags);
+ /*
+ * this search will find the extents that end after
+ * our range starts
+ */
+ node = tree_search(&tree->state, start);
+ if (!node)
+ goto out;
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->start > end)
+ goto out;
+ WARN_ON(state->end < start);
+
+ /*
+ * | ---- desired range ---- |
+ * | state | or
+ * | ------------- state -------------- |
+ *
+ * We need to split the extent we found, and may flip
+ * bits on second half.
+ *
+ * If the extent we found extends past our range, we
+ * just split and search again. It'll get split again
+ * the next time though.
+ *
+ * If the extent we found is inside our range, we clear
+ * the desired bit on it.
+ */
+
+ if (state->start < start) {
+ err = split_state(tree, state, prealloc, start);
+ BUG_ON(err == -EEXIST);
+ prealloc = NULL;
+ if (err)
+ goto out;
+ if (state->end <= end) {
+ start = state->end + 1;
+ set |= clear_state_bit(tree, state, bits,
+ wake, delete);
+ } else {
+ start = state->start;
+ }
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * We need to split the extent, and clear the bit
+ * on the first half
+ */
+ if (state->start <= end && state->end > end) {
+ err = split_state(tree, state, prealloc, end + 1);
+ BUG_ON(err == -EEXIST);
+
+ if (wake)
+ wake_up(&state->wq);
+ set |= clear_state_bit(tree, prealloc, bits,
+ wake, delete);
+ prealloc = NULL;
+ goto out;
+ }
+
+ start = state->end + 1;
+ set |= clear_state_bit(tree, state, bits, wake, delete);
+ goto search_again;
+
+out:
+ write_unlock_irqrestore(&tree->lock, flags);
+ if (prealloc)
+ free_extent_state(prealloc);
+
+ return set;
+
+search_again:
+ if (start > end)
+ goto out;
+ write_unlock_irqrestore(&tree->lock, flags);
+ if (mask & __GFP_WAIT)
+ cond_resched();
+ goto again;
+}
+EXPORT_SYMBOL(clear_extent_bit);
+
+static int wait_on_state(struct extent_io_tree *tree,
+ struct extent_state *state)
+{
+ DEFINE_WAIT(wait);
+ prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
+ read_unlock_irq(&tree->lock);
+ schedule();
+ read_lock_irq(&tree->lock);
+ finish_wait(&state->wq, &wait);
+ return 0;
+}
+
+/*
+ * waits for one or more bits to clear on a range in the state tree.
+ * The range [start, end] is inclusive.
+ * The tree lock is taken by this function
+ */
+int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
+{
+ struct extent_state *state;
+ struct rb_node *node;
+
+ read_lock_irq(&tree->lock);
+again:
+ while (1) {
+ /*
+ * this search will find all the extents that end after
+ * our range starts
+ */
+ node = tree_search(&tree->state, start);
+ if (!node)
+ break;
+
+ state = rb_entry(node, struct extent_state, rb_node);
+
+ if (state->start > end)
+ goto out;
+
+ if (state->state & bits) {
+ start = state->start;
+ atomic_inc(&state->refs);
+ wait_on_state(tree, state);
+ free_extent_state(state);
+ goto again;
+ }
+ start = state->end + 1;
+
+ if (start > end)
+ break;
+
+ if (need_resched()) {
+ read_unlock_irq(&tree->lock);
+ cond_resched();
+ read_lock_irq(&tree->lock);
+ }
+ }
+out:
+ read_unlock_irq(&tree->lock);
+ return 0;
+}
+EXPORT_SYMBOL(wait_extent_bit);
+
+static void set_state_bits(struct extent_io_tree *tree,
+ struct extent_state *state,
+ int bits)
+{
+ if ((bits & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
+ u64 range = state->end - state->start + 1;
+ tree->dirty_bytes += range;
+ }
+ state->state |= bits;
+}
+
+/*
+ * set some bits on a range in the tree. This may require allocations
+ * or sleeping, so the gfp mask is used to indicate what is allowed.
+ *
+ * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
+ * range already has the desired bits set. The start of the existing
+ * range is returned in failed_start in this case.
+ *
+ * [start, end] is inclusive
+ * This takes the tree lock.
+ */
+int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits,
+ int exclusive, u64 *failed_start, gfp_t mask)
+{
+ struct extent_state *state;
+ struct extent_state *prealloc = NULL;
+ struct rb_node *node;
+ unsigned long flags;
+ int err = 0;
+ int set;
+ u64 last_start;
+ u64 last_end;
+again:
+ if (!prealloc && (mask & __GFP_WAIT)) {
+ prealloc = alloc_extent_state(mask);
+ if (!prealloc)
+ return -ENOMEM;
+ }
+
+ write_lock_irqsave(&tree->lock, flags);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(&tree->state, start);
+ if (!node) {
+ err = insert_state(tree, prealloc, start, end, bits);
+ prealloc = NULL;
+ BUG_ON(err == -EEXIST);
+ goto out;
+ }
+
+ state = rb_entry(node, struct extent_state, rb_node);
+ last_start = state->start;
+ last_end = state->end;
+
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ *
+ * Just lock what we found and keep going
+ */
+ if (state->start == start && state->end <= end) {
+ set = state->state & bits;
+ if (set && exclusive) {
+ *failed_start = state->start;
+ err = -EEXIST;
+ goto out;
+ }
+ set_state_bits(tree, state, bits);
+ start = state->end + 1;
+ merge_state(tree, state);
+ goto search_again;
+ }
+
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * or
+ * | ------------- state -------------- |
+ *
+ * We need to split the extent we found, and may flip bits on
+ * second half.
+ *
+ * If the extent we found extends past our
+ * range, we just split and search again. It'll get split
+ * again the next time though.
+ *
+ * If the extent we found is inside our range, we set the
+ * desired bit on it.
+ */
+ if (state->start < start) {
+ set = state->state & bits;
+ if (exclusive && set) {
+ *failed_start = start;
+ err = -EEXIST;
+ goto out;
+ }
+ err = split_state(tree, state, prealloc, start);
+ BUG_ON(err == -EEXIST);
+ prealloc = NULL;
+ if (err)
+ goto out;
+ if (state->end <= end) {
+ set_state_bits(tree, state, bits);
+ start = state->end + 1;
+ merge_state(tree, state);
+ } else {
+ start = state->start;
+ }
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state | or | state |
+ *
+ * There's a hole, we need to insert something in it and
+ * ignore the extent we found.
+ */
+ if (state->start > start) {
+ u64 this_end;
+ if (end < last_start)
+ this_end = end;
+ else
+ this_end = last_start -1;
+ err = insert_state(tree, prealloc, start, this_end,
+ bits);
+ prealloc = NULL;
+ BUG_ON(err == -EEXIST);
+ if (err)
+ goto out;
+ start = this_end + 1;
+ goto search_again;
+ }
+ /*
+ * | ---- desired range ---- |
+ * | state |
+ * We need to split the extent, and set the bit
+ * on the first half
+ */
+ if (state->start <= end && state->end > end) {
+ set = state->state & bits;
+ if (exclusive && set) {
+ *failed_start = start;
+ err = -EEXIST;
+ goto out;
+ }
+ err = split_state(tree, state, prealloc, end + 1);
+ BUG_ON(err == -EEXIST);
+
+ set_state_bits(tree, prealloc, bits);
+ merge_state(tree, prealloc);
+ prealloc = NULL;
+ goto out;
+ }
+
+ goto search_again;
+
+out:
+ write_unlock_irqrestore(&tree->lock, flags);
+ if (prealloc)
+ free_extent_state(prealloc);
+
+ return err;
+
+search_again:
+ if (start > end)
+ goto out;
+ write_unlock_irqrestore(&tree->lock, flags);
+ if (mask & __GFP_WAIT)
+ cond_resched();
+ goto again;
+}
+EXPORT_SYMBOL(set_extent_bit);
+
+/* wrappers around set/clear extent bit */
+int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
+ mask);
+}
+EXPORT_SYMBOL(set_extent_dirty);
+
+int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
+ int bits, gfp_t mask)
+{
+ return set_extent_bit(tree, start, end, bits, 0, NULL,
+ mask);
+}
+EXPORT_SYMBOL(set_extent_bits);
+
+int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
+ int bits, gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end, bits, 0, 0, mask);
+}
+EXPORT_SYMBOL(clear_extent_bits);
+
+int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return set_extent_bit(tree, start, end,
+ EXTENT_DELALLOC | EXTENT_DIRTY, 0, NULL,
+ mask);
+}
+EXPORT_SYMBOL(set_extent_delalloc);
+
+int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end,
+ EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, mask);
+}
+EXPORT_SYMBOL(clear_extent_dirty);
+
+int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
+ mask);
+}
+EXPORT_SYMBOL(set_extent_new);
+
+int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
+}
+EXPORT_SYMBOL(clear_extent_new);
+
+int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
+ mask);
+}
+EXPORT_SYMBOL(set_extent_uptodate);
+
+int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
+}
+EXPORT_SYMBOL(clear_extent_uptodate);
+
+int set_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
+ 0, NULL, mask);
+}
+EXPORT_SYMBOL(set_extent_writeback);
+
+int clear_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
+}
+EXPORT_SYMBOL(clear_extent_writeback);
+
+int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
+{
+ return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
+}
+EXPORT_SYMBOL(wait_on_extent_writeback);
+
+/*
+ * locks a range in ascending order, waiting for any locked regions
+ * it hits on the way. [start,end] are inclusive, and this will sleep.
+ */
+int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
+{
+ int err;
+ u64 failed_start;
+ while (1) {
+ err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
+ &failed_start, mask);
+ if (err == -EEXIST && (mask & __GFP_WAIT)) {
+ wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
+ start = failed_start;
+ } else {
+ break;
+ }
+ WARN_ON(start > end);
+ }
+ return err;
+}
+EXPORT_SYMBOL(lock_extent);
+
+int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
+}
+EXPORT_SYMBOL(unlock_extent);
+
+/*
+ * helper function to set pages and extents in the tree dirty
+ */
+int set_range_dirty(struct extent_io_tree *tree, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(tree->mapping, index);
+ BUG_ON(!page);
+ __set_page_dirty_nobuffers(page);
+ page_cache_release(page);
+ index++;
+ }
+ set_extent_dirty(tree, start, end, GFP_NOFS);
+ return 0;
+}
+EXPORT_SYMBOL(set_range_dirty);
+
+/*
+ * helper function to set both pages and extents in the tree writeback
+ */
+int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(tree->mapping, index);
+ BUG_ON(!page);
+ set_page_writeback(page);
+ page_cache_release(page);
+ index++;
+ }
+ set_extent_writeback(tree, start, end, GFP_NOFS);
+ return 0;
+}
+EXPORT_SYMBOL(set_range_writeback);
+
+int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
+ u64 *start_ret, u64 *end_ret, int bits)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ int ret = 1;
+
+ read_lock_irq(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(&tree->state, start);
+ if (!node || IS_ERR(node)) {
+ goto out;
+ }
+
+ while(1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->end >= start && (state->state & bits)) {
+ *start_ret = state->start;
+ *end_ret = state->end;
+ ret = 0;
+ break;
+ }
+ node = rb_next(node);
+ if (!node)
+ break;
+ }
+out:
+ read_unlock_irq(&tree->lock);
+ return ret;
+}
+EXPORT_SYMBOL(find_first_extent_bit);
+
+u64 find_lock_delalloc_range(struct extent_io_tree *tree,
+ u64 *start, u64 *end, u64 max_bytes)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ u64 cur_start = *start;
+ u64 found = 0;
+ u64 total_bytes = 0;
+
+ write_lock_irq(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+search_again:
+ node = tree_search(&tree->state, cur_start);
+ if (!node || IS_ERR(node)) {
+ *end = (u64)-1;
+ goto out;
+ }
+
+ while(1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (found && state->start != cur_start) {
+ goto out;
+ }
+ if (!(state->state & EXTENT_DELALLOC)) {
+ if (!found)
+ *end = state->end;
+ goto out;
+ }
+ if (!found) {
+ struct extent_state *prev_state;
+ struct rb_node *prev_node = node;
+ while(1) {
+ prev_node = rb_prev(prev_node);
+ if (!prev_node)
+ break;
+ prev_state = rb_entry(prev_node,
+ struct extent_state,
+ rb_node);
+ if (!(prev_state->state & EXTENT_DELALLOC))
+ break;
+ state = prev_state;
+ node = prev_node;
+ }
+ }
+ if (state->state & EXTENT_LOCKED) {
+ DEFINE_WAIT(wait);
+ atomic_inc(&state->refs);
+ prepare_to_wait(&state->wq, &wait,
+ TASK_UNINTERRUPTIBLE);
+ write_unlock_irq(&tree->lock);
+ schedule();
+ write_lock_irq(&tree->lock);
+ finish_wait(&state->wq, &wait);
+ free_extent_state(state);
+ goto search_again;
+ }
+ state->state |= EXTENT_LOCKED;
+ if (!found)
+ *start = state->start;
+ found++;
+ *end = state->end;
+ cur_start = state->end + 1;
+ node = rb_next(node);
+ if (!node)
+ break;
+ total_bytes += state->end - state->start + 1;
+ if (total_bytes >= max_bytes)
+ break;
+ }
+out:
+ write_unlock_irq(&tree->lock);
+ return found;
+}
+
+u64 count_range_bits(struct extent_io_tree *tree,
+ u64 *start, u64 search_end, u64 max_bytes,
+ unsigned long bits)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ u64 cur_start = *start;
+ u64 total_bytes = 0;
+ int found = 0;
+
+ if (search_end <= cur_start) {
+ printk("search_end %Lu start %Lu\n", search_end, cur_start);
+ WARN_ON(1);
+ return 0;
+ }
+
+ write_lock_irq(&tree->lock);
+ if (cur_start == 0 && bits == EXTENT_DIRTY) {
+ total_bytes = tree->dirty_bytes;
+ goto out;
+ }
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(&tree->state, cur_start);
+ if (!node || IS_ERR(node)) {
+ goto out;
+ }
+
+ while(1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->start > search_end)
+ break;
+ if (state->end >= cur_start && (state->state & bits)) {
+ total_bytes += min(search_end, state->end) + 1 -
+ max(cur_start, state->start);
+ if (total_bytes >= max_bytes)
+ break;
+ if (!found) {
+ *start = state->start;
+ found = 1;
+ }
+ }
+ node = rb_next(node);
+ if (!node)
+ break;
+ }
+out:
+ write_unlock_irq(&tree->lock);
+ return total_bytes;
+}
+/*
+ * helper function to lock both pages and extents in the tree.
+ * pages must be locked first.
+ */
+int lock_range(struct extent_io_tree *tree, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+ int err;
+
+ while (index <= end_index) {
+ page = grab_cache_page(tree->mapping, index);
+ if (!page) {
+ err = -ENOMEM;
+ goto failed;
+ }
+ if (IS_ERR(page)) {
+ err = PTR_ERR(page);
+ goto failed;
+ }
+ index++;
+ }
+ lock_extent(tree, start, end, GFP_NOFS);
+ return 0;
+
+failed:
+ /*
+ * we failed above in getting the page at 'index', so we undo here
+ * up to but not including the page at 'index'
+ */
+ end_index = index;
+ index = start >> PAGE_CACHE_SHIFT;
+ while (index < end_index) {
+ page = find_get_page(tree->mapping, index);
+ unlock_page(page);
+ page_cache_release(page);
+ index++;
+ }
+ return err;
+}
+EXPORT_SYMBOL(lock_range);
+
+/*
+ * helper function to unlock both pages and extents in the tree.
+ */
+int unlock_range(struct extent_io_tree *tree, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(tree->mapping, index);
+ unlock_page(page);
+ page_cache_release(page);
+ index++;
+ }
+ unlock_extent(tree, start, end, GFP_NOFS);
+ return 0;
+}
+EXPORT_SYMBOL(unlock_range);
+
+int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ int ret = 0;
+
+ write_lock_irq(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(&tree->state, start);
+ if (!node || IS_ERR(node)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->start != start) {
+ ret = -ENOENT;
+ goto out;
+ }
+ state->private = private;
+out:
+ write_unlock_irq(&tree->lock);
+ return ret;
+}
+
+int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ int ret = 0;
+
+ read_lock_irq(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(&tree->state, start);
+ if (!node || IS_ERR(node)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->start != start) {
+ ret = -ENOENT;
+ goto out;
+ }
+ *private = state->private;
+out:
+ read_unlock_irq(&tree->lock);
+ return ret;
+}
+
+/*
+ * searches a range in the state tree for a given mask.
+ * If 'filled' == 1, this returns 1 only if ever extent in the tree
+ * has the bits set. Otherwise, 1 is returned if any bit in the
+ * range is found set.
+ */
+int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
+ int bits, int filled)
+{
+ struct extent_state *state = NULL;
+ struct rb_node *node;
+ int bitset = 0;
+ unsigned long flags;
+
+ read_lock_irqsave(&tree->lock, flags);
+ node = tree_search(&tree->state, start);
+ while (node && start <= end) {
+ state = rb_entry(node, struct extent_state, rb_node);
+
+ if (filled && state->start > start) {
+ bitset = 0;
+ break;
+ }
+
+ if (state->start > end)
+ break;
+
+ if (state->state & bits) {
+ bitset = 1;
+ if (!filled)
+ break;
+ } else if (filled) {
+ bitset = 0;
+ break;
+ }
+ start = state->end + 1;
+ if (start > end)
+ break;
+ node = rb_next(node);
+ if (!node) {
+ if (filled)
+ bitset = 0;
+ break;
+ }
+ }
+ read_unlock_irqrestore(&tree->lock, flags);
+ return bitset;
+}
+EXPORT_SYMBOL(test_range_bit);
+
+/*
+ * helper function to set a given page up to date if all the
+ * extents in the tree for that page are up to date
+ */
+static int check_page_uptodate(struct extent_io_tree *tree,
+ struct page *page)
+{
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+ if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
+ SetPageUptodate(page);
+ return 0;
+}
+
+/*
+ * helper function to unlock a page if all the extents in the tree
+ * for that page are unlocked
+ */
+static int check_page_locked(struct extent_io_tree *tree,
+ struct page *page)
+{
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+ if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
+ unlock_page(page);
+ return 0;
+}
+
+/*
+ * helper function to end page writeback if all the extents
+ * in the tree for that page are done with writeback
+ */
+static int check_page_writeback(struct extent_io_tree *tree,
+ struct page *page)
+{
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+ if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
+ end_page_writeback(page);
+ return 0;
+}
+
+/* lots and lots of room for performance fixes in the end_bio funcs */
+
+/*
+ * after a writepage IO is done, we need to:
+ * clear the uptodate bits on error
+ * clear the writeback bits in the extent tree for this IO
+ * end_page_writeback if the page has no more pending IO
+ *
+ * Scheduling is not allowed, so the extent state tree is expected
+ * to have one and only one object corresponding to this IO.
+ */
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
+static void end_bio_extent_writepage(struct bio *bio, int err)
+#else
+static int end_bio_extent_writepage(struct bio *bio,
+ unsigned int bytes_done, int err)
+#endif
+{
+ const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct extent_io_tree *tree = bio->bi_private;
+ u64 start;
+ u64 end;
+ int whole_page;
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
+ if (bio->bi_size)
+ return 1;
+#endif
+
+ do {
+ struct page *page = bvec->bv_page;
+ start = ((u64)page->index << PAGE_CACHE_SHIFT) +
+ bvec->bv_offset;
+ end = start + bvec->bv_len - 1;
+
+ if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
+ whole_page = 1;
+ else
+ whole_page = 0;
+
+ if (--bvec >= bio->bi_io_vec)
+ prefetchw(&bvec->bv_page->flags);
+
+ if (!uptodate) {
+ clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+ clear_extent_writeback(tree, start, end, GFP_ATOMIC);
+
+ if (whole_page)
+ end_page_writeback(page);
+ else
+ check_page_writeback(tree, page);
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, start, end);
+ } while (bvec >= bio->bi_io_vec);
+
+ bio_put(bio);
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
+ return 0;
+#endif
+}
+
+/*
+ * after a readpage IO is done, we need to:
+ * clear the uptodate bits on error
+ * set the uptodate bits if things worked
+ * set the page up to date if all extents in the tree are uptodate
+ * clear the lock bit in the extent tree
+ * unlock the page if there are no other extents locked for it
+ *
+ * Scheduling is not allowed, so the extent state tree is expected
+ * to have one and only one object corresponding to this IO.
+ */
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
+static void end_bio_extent_readpage(struct bio *bio, int err)
+#else
+static int end_bio_extent_readpage(struct bio *bio,
+ unsigned int bytes_done, int err)
+#endif
+{
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct extent_io_tree *tree = bio->bi_private;
+ u64 start;
+ u64 end;
+ int whole_page;
+ int ret;
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
+ if (bio->bi_size)
+ return 1;
+#endif
+
+ do {
+ struct page *page = bvec->bv_page;
+ start = ((u64)page->index << PAGE_CACHE_SHIFT) +
+ bvec->bv_offset;
+ end = start + bvec->bv_len - 1;
+
+ if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
+ whole_page = 1;
+ else
+ whole_page = 0;
+
+ if (--bvec >= bio->bi_io_vec)
+ prefetchw(&bvec->bv_page->flags);
+
+ if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
+ ret = tree->ops->readpage_end_io_hook(page, start, end);
+ if (ret)
+ uptodate = 0;
+ }
+ if (uptodate) {
+ set_extent_uptodate(tree, start, end, GFP_ATOMIC);
+ if (whole_page)
+ SetPageUptodate(page);
+ else
+ check_page_uptodate(tree, page);
+ } else {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+
+ unlock_extent(tree, start, end, GFP_ATOMIC);
+
+ if (whole_page)
+ unlock_page(page);
+ else
+ check_page_locked(tree, page);
+ } while (bvec >= bio->bi_io_vec);
+
+ bio_put(bio);
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
+ return 0;
+#endif
+}
+
+/*
+ * IO done from prepare_write is pretty simple, we just unlock
+ * the structs in the extent tree when done, and set the uptodate bits
+ * as appropriate.
+ */
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
+static void end_bio_extent_preparewrite(struct bio *bio, int err)
+#else
+static int end_bio_extent_preparewrite(struct bio *bio,
+ unsigned int bytes_done, int err)
+#endif
+{
+ const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct extent_io_tree *tree = bio->bi_private;
+ u64 start;
+ u64 end;
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
+ if (bio->bi_size)
+ return 1;
+#endif
+
+ do {
+ struct page *page = bvec->bv_page;
+ start = ((u64)page->index << PAGE_CACHE_SHIFT) +
+ bvec->bv_offset;
+ end = start + bvec->bv_len - 1;
+
+ if (--bvec >= bio->bi_io_vec)
+ prefetchw(&bvec->bv_page->flags);
+
+ if (uptodate) {
+ set_extent_uptodate(tree, start, end, GFP_ATOMIC);
+ } else {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+
+ unlock_extent(tree, start, end, GFP_ATOMIC);
+
+ } while (bvec >= bio->bi_io_vec);
+
+ bio_put(bio);
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
+ return 0;
+#endif
+}
+
+static struct bio *
+extent_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
+ gfp_t gfp_flags)
+{
+ struct bio *bio;
+
+ bio = bio_alloc(gfp_flags, nr_vecs);
+
+ if (bio == NULL && (current->flags & PF_MEMALLOC)) {
+ while (!bio && (nr_vecs /= 2))
+ bio = bio_alloc(gfp_flags, nr_vecs);
+ }
+
+ if (bio) {
+ bio->bi_bdev = bdev;
+ bio->bi_sector = first_sector;
+ }
+ return bio;
+}
+
+static int submit_one_bio(int rw, struct bio *bio)
+{
+ u64 maxsector;
+ int ret = 0;
+
+ bio_get(bio);
+
+ maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
+ if (maxsector < bio->bi_sector) {
+ printk("sector too large max %Lu got %llu\n", maxsector,
+ (unsigned long long)bio->bi_sector);
+ WARN_ON(1);
+ }
+
+ submit_bio(rw, bio);
+ if (bio_flagged(bio, BIO_EOPNOTSUPP))
+ ret = -EOPNOTSUPP;
+ bio_put(bio);
+ return ret;
+}
+
+static int submit_extent_page(int rw, struct extent_io_tree *tree,
+ struct page *page, sector_t sector,
+ size_t size, unsigned long offset,
+ struct block_device *bdev,
+ struct bio **bio_ret,
+ unsigned long max_pages,
+ bio_end_io_t end_io_func)
+{
+ int ret = 0;
+ struct bio *bio;
+ int nr;
+
+ if (bio_ret && *bio_ret) {
+ bio = *bio_ret;
+ if (bio->bi_sector + (bio->bi_size >> 9) != sector ||
+ bio_add_page(bio, page, size, offset) < size) {
+ ret = submit_one_bio(rw, bio);
+ bio = NULL;
+ } else {
+ return 0;
+ }
+ }
+ nr = min_t(int, max_pages, bio_get_nr_vecs(bdev));
+ bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
+ if (!bio) {
+ printk("failed to allocate bio nr %d\n", nr);
+ }
+ bio_add_page(bio, page, size, offset);
+ bio->bi_end_io = end_io_func;
+ bio->bi_private = tree;
+ if (bio_ret) {
+ *bio_ret = bio;
+ } else {
+ ret = submit_one_bio(rw, bio);
+ }
+
+ return ret;
+}
+
+void set_page_extent_mapped(struct page *page)
+{
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ WARN_ON(!page->mapping->a_ops->invalidatepage);
+ set_page_private(page, EXTENT_PAGE_PRIVATE);
+ page_cache_get(page);
+ }
+}
+
+void set_page_extent_head(struct page *page, unsigned long len)
+{
+ set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
+}
+
+/*
+ * basic readpage implementation. Locked extent state structs are inserted
+ * into the tree that are removed when the IO is done (by the end_io
+ * handlers)
+ */
+static int __extent_read_full_page(struct extent_io_tree *tree,
+ struct page *page,
+ get_extent_t *get_extent,
+ struct bio **bio)
+{
+ struct inode *inode = page->mapping->host;
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 page_end = start + PAGE_CACHE_SIZE - 1;
+ u64 end;
+ u64 cur = start;
+ u64 extent_offset;
+ u64 last_byte = i_size_read(inode);
+ u64 block_start;
+ u64 cur_end;
+ sector_t sector;
+ struct extent_map *em;
+ struct block_device *bdev;
+ int ret;
+ int nr = 0;
+ size_t page_offset = 0;
+ size_t iosize;
+ size_t blocksize = inode->i_sb->s_blocksize;
+
+ set_page_extent_mapped(page);
+
+ end = page_end;
+ lock_extent(tree, start, end, GFP_NOFS);
+
+ while (cur <= end) {
+ if (cur >= last_byte) {
+ char *userpage;
+ iosize = PAGE_CACHE_SIZE - page_offset;
+ userpage = kmap_atomic(page, KM_USER0);
+ memset(userpage + page_offset, 0, iosize);
+ flush_dcache_page(page);
+ kunmap_atomic(userpage, KM_USER0);
+ set_extent_uptodate(tree, cur, cur + iosize - 1,
+ GFP_NOFS);
+ unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
+ break;
+ }
+ em = get_extent(inode, page, page_offset, cur,
+ end - cur + 1, 0);
+ if (IS_ERR(em) || !em) {
+ SetPageError(page);
+ unlock_extent(tree, cur, end, GFP_NOFS);
+ break;
+ }
+
+ extent_offset = cur - em->start;
+ BUG_ON(extent_map_end(em) <= cur);
+ BUG_ON(end < cur);
+
+ iosize = min(extent_map_end(em) - cur, end - cur + 1);
+ cur_end = min(extent_map_end(em) - 1, end);
+ iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
+ sector = (em->block_start + extent_offset) >> 9;
+ bdev = em->bdev;
+ block_start = em->block_start;
+ free_extent_map(em);
+ em = NULL;
+
+ /* we've found a hole, just zero and go on */
+ if (block_start == EXTENT_MAP_HOLE) {
+ char *userpage;
+ userpage = kmap_atomic(page, KM_USER0);
+ memset(userpage + page_offset, 0, iosize);
+ flush_dcache_page(page);
+ kunmap_atomic(userpage, KM_USER0);
+
+ set_extent_uptodate(tree, cur, cur + iosize - 1,
+ GFP_NOFS);
+ unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
+ cur = cur + iosize;
+ page_offset += iosize;
+ continue;
+ }
+ /* the get_extent function already copied into the page */
+ if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
+ unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
+ cur = cur + iosize;
+ page_offset += iosize;
+ continue;
+ }
+
+ ret = 0;
+ if (tree->ops && tree->ops->readpage_io_hook) {
+ ret = tree->ops->readpage_io_hook(page, cur,
+ cur + iosize - 1);
+ }
+ if (!ret) {
+ unsigned long nr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
+ nr -= page->index;
+ ret = submit_extent_page(READ, tree, page,
+ sector, iosize, page_offset,
+ bdev, bio, nr,
+ end_bio_extent_readpage);
+ }
+ if (ret)
+ SetPageError(page);
+ cur = cur + iosize;
+ page_offset += iosize;
+ nr++;
+ }
+ if (!nr) {
+ if (!PageError(page))
+ SetPageUptodate(page);
+ unlock_page(page);
+ }
+ return 0;
+}
+
+int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
+ get_extent_t *get_extent)
+{
+ struct bio *bio = NULL;
+ int ret;
+
+ ret = __extent_read_full_page(tree, page, get_extent, &bio);
+ if (bio)
+ submit_one_bio(READ, bio);
+ return ret;
+}
+EXPORT_SYMBOL(extent_read_full_page);
+
+/*
+ * the writepage semantics are similar to regular writepage. extent
+ * records are inserted to lock ranges in the tree, and as dirty areas
+ * are found, they are marked writeback. Then the lock bits are removed
+ * and the end_io handler clears the writeback ranges
+ */
+static int __extent_writepage(struct page *page, struct writeback_control *wbc,
+ void *data)
+{
+ struct inode *inode = page->mapping->host;
+ struct extent_page_data *epd = data;
+ struct extent_io_tree *tree = epd->tree;
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 delalloc_start;
+ u64 page_end = start + PAGE_CACHE_SIZE - 1;
+ u64 end;
+ u64 cur = start;
+ u64 extent_offset;
+ u64 last_byte = i_size_read(inode);
+ u64 block_start;
+ u64 iosize;
+ sector_t sector;
+ struct extent_map *em;
+ struct block_device *bdev;
+ int ret;
+ int nr = 0;
+ size_t page_offset = 0;
+ size_t blocksize;
+ loff_t i_size = i_size_read(inode);
+ unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
+ u64 nr_delalloc;
+ u64 delalloc_end;
+
+ WARN_ON(!PageLocked(page));
+ if (page->index > end_index) {
+ clear_extent_dirty(tree, start, page_end, GFP_NOFS);
+ unlock_page(page);
+ return 0;
+ }
+
+ if (page->index == end_index) {
+ char *userpage;
+
+ size_t offset = i_size & (PAGE_CACHE_SIZE - 1);
+
+ userpage = kmap_atomic(page, KM_USER0);
+ memset(userpage + offset, 0, PAGE_CACHE_SIZE - offset);
+ flush_dcache_page(page);
+ kunmap_atomic(userpage, KM_USER0);
+ }
+
+ set_page_extent_mapped(page);
+
+ delalloc_start = start;
+ delalloc_end = 0;
+ while(delalloc_end < page_end) {
+ nr_delalloc = find_lock_delalloc_range(tree, &delalloc_start,
+ &delalloc_end,
+ 128 * 1024 * 1024);
+ if (nr_delalloc == 0) {
+ delalloc_start = delalloc_end + 1;
+ continue;
+ }
+ tree->ops->fill_delalloc(inode, delalloc_start,
+ delalloc_end);
+ clear_extent_bit(tree, delalloc_start,
+ delalloc_end,
+ EXTENT_LOCKED | EXTENT_DELALLOC,
+ 1, 0, GFP_NOFS);
+ delalloc_start = delalloc_end + 1;
+ }
+ lock_extent(tree, start, page_end, GFP_NOFS);
+
+ end = page_end;
+ if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
+ printk("found delalloc bits after lock_extent\n");
+ }
+
+ if (last_byte <= start) {
+ clear_extent_dirty(tree, start, page_end, GFP_NOFS);
+ goto done;
+ }
+
+ set_extent_uptodate(tree, start, page_end, GFP_NOFS);
+ blocksize = inode->i_sb->s_blocksize;
+
+ while (cur <= end) {
+ if (cur >= last_byte) {
+ clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
+ break;
+ }
+ em = epd->get_extent(inode, page, page_offset, cur,
+ end - cur + 1, 1);
+ if (IS_ERR(em) || !em) {
+ SetPageError(page);
+ break;
+ }
+
+ extent_offset = cur - em->start;
+ BUG_ON(extent_map_end(em) <= cur);
+ BUG_ON(end < cur);
+ iosize = min(extent_map_end(em) - cur, end - cur + 1);
+ iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
+ sector = (em->block_start + extent_offset) >> 9;
+ bdev = em->bdev;
+ block_start = em->block_start;
+ free_extent_map(em);
+ em = NULL;
+
+ if (block_start == EXTENT_MAP_HOLE ||
+ block_start == EXTENT_MAP_INLINE) {
+ clear_extent_dirty(tree, cur,
+ cur + iosize - 1, GFP_NOFS);
+ cur = cur + iosize;
+ page_offset += iosize;
+ continue;
+ }
+
+ /* leave this out until we have a page_mkwrite call */
+ if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
+ EXTENT_DIRTY, 0)) {
+ cur = cur + iosize;
+ page_offset += iosize;
+ continue;
+ }
+ clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
+ if (tree->ops && tree->ops->writepage_io_hook) {
+ ret = tree->ops->writepage_io_hook(page, cur,
+ cur + iosize - 1);
+ } else {
+ ret = 0;
+ }
+ if (ret)
+ SetPageError(page);
+ else {
+ unsigned long max_nr = end_index + 1;
+ set_range_writeback(tree, cur, cur + iosize - 1);
+ if (!PageWriteback(page)) {
+ printk("warning page %lu not writeback, "
+ "cur %llu end %llu\n", page->index,
+ (unsigned long long)cur,
+ (unsigned long long)end);
+ }
+
+ ret = submit_extent_page(WRITE, tree, page, sector,
+ iosize, page_offset, bdev,
+ &epd->bio, max_nr,
+ end_bio_extent_writepage);
+ if (ret)
+ SetPageError(page);
+ }
+ cur = cur + iosize;
+ page_offset += iosize;
+ nr++;
+ }
+done:
+ if (nr == 0) {
+ /* make sure the mapping tag for page dirty gets cleared */
+ set_page_writeback(page);
+ end_page_writeback(page);
+ }
+ unlock_extent(tree, start, page_end, GFP_NOFS);
+ unlock_page(page);
+ return 0;
+}
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
+
+/* Taken directly from 2.6.23 for 2.6.18 back port */
+typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
+ void *data);
+
+/**
+ * write_cache_pages - walk the list of dirty pages of the given address space
+ * and write all of them.
+ * @mapping: address space structure to write
+ * @wbc: subtract the number of written pages from *@wbc->nr_to_write
+ * @writepage: function called for each page
+ * @data: data passed to writepage function
+ *
+ * If a page is already under I/O, write_cache_pages() skips it, even
+ * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
+ * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
+ * and msync() need to guarantee that all the data which was dirty at the time
+ * the call was made get new I/O started against them. If wbc->sync_mode is
+ * WB_SYNC_ALL then we were called for data integrity and we must wait for
+ * existing IO to complete.
+ */
+static int write_cache_pages(struct address_space *mapping,
+ struct writeback_control *wbc, writepage_t writepage,
+ void *data)
+{
+ struct backing_dev_info *bdi = mapping->backing_dev_info;
+ int ret = 0;
+ int done = 0;
+ struct pagevec pvec;
+ int nr_pages;
+ pgoff_t index;
+ pgoff_t end; /* Inclusive */
+ int scanned = 0;
+ int range_whole = 0;
+
+ if (wbc->nonblocking && bdi_write_congested(bdi)) {
+ wbc->encountered_congestion = 1;
+ return 0;
+ }
+
+ pagevec_init(&pvec, 0);
+ if (wbc->range_cyclic) {
+ index = mapping->writeback_index; /* Start from prev offset */
+ end = -1;
+ } else {
+ index = wbc->range_start >> PAGE_CACHE_SHIFT;
+ end = wbc->range_end >> PAGE_CACHE_SHIFT;
+ if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+ range_whole = 1;
+ scanned = 1;
+ }
+retry:
+ while (!done && (index <= end) &&
+ (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+ PAGECACHE_TAG_DIRTY,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
+ unsigned i;
+
+ scanned = 1;
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+
+ /*
+ * At this point we hold neither mapping->tree_lock nor
+ * lock on the page itself: the page may be truncated or
+ * invalidated (changing page->mapping to NULL), or even
+ * swizzled back from swapper_space to tmpfs file
+ * mapping
+ */
+ lock_page(page);
+
+ if (unlikely(page->mapping != mapping)) {
+ unlock_page(page);
+ continue;
+ }
+
+ if (!wbc->range_cyclic && page->index > end) {
+ done = 1;
+ unlock_page(page);
+ continue;
+ }
+
+ if (wbc->sync_mode != WB_SYNC_NONE)
+ wait_on_page_writeback(page);
+
+ if (PageWriteback(page) ||
+ !clear_page_dirty_for_io(page)) {
+ unlock_page(page);
+ continue;
+ }
+
+ ret = (*writepage)(page, wbc, data);
+
+ if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
+ unlock_page(page);
+ ret = 0;
+ }
+ if (ret || (--(wbc->nr_to_write) <= 0))
+ done = 1;
+ if (wbc->nonblocking && bdi_write_congested(bdi)) {
+ wbc->encountered_congestion = 1;
+ done = 1;
+ }
+ }
+ pagevec_release(&pvec);
+ cond_resched();
+ }
+ if (!scanned && !done) {
+ /*
+ * We hit the last page and there is more work to be done: wrap
+ * back to the start of the file
+ */
+ scanned = 1;
+ index = 0;
+ goto retry;
+ }
+ if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+ mapping->writeback_index = index;
+ return ret;
+}
+#endif
+
+int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
+ get_extent_t *get_extent,
+ struct writeback_control *wbc)
+{
+ int ret;
+ struct address_space *mapping = page->mapping;
+ struct extent_page_data epd = {
+ .bio = NULL,
+ .tree = tree,
+ .get_extent = get_extent,
+ };
+ struct writeback_control wbc_writepages = {
+ .bdi = wbc->bdi,
+ .sync_mode = WB_SYNC_NONE,
+ .older_than_this = NULL,
+ .nr_to_write = 64,
+ .range_start = page_offset(page) + PAGE_CACHE_SIZE,
+ .range_end = (loff_t)-1,
+ };
+
+
+ ret = __extent_writepage(page, wbc, &epd);
+
+ write_cache_pages(mapping, &wbc_writepages, __extent_writepage, &epd);
+ if (epd.bio) {
+ submit_one_bio(WRITE, epd.bio);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(extent_write_full_page);
+
+
+int extent_writepages(struct extent_io_tree *tree,
+ struct address_space *mapping,
+ get_extent_t *get_extent,
+ struct writeback_control *wbc)
+{
+ int ret = 0;
+ struct extent_page_data epd = {
+ .bio = NULL,
+ .tree = tree,
+ .get_extent = get_extent,
+ };
+
+ ret = write_cache_pages(mapping, wbc, __extent_writepage, &epd);
+ if (epd.bio) {
+ submit_one_bio(WRITE, epd.bio);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(extent_writepages);
+
+int extent_readpages(struct extent_io_tree *tree,
+ struct address_space *mapping,
+ struct list_head *pages, unsigned nr_pages,
+ get_extent_t get_extent)
+{
+ struct bio *bio = NULL;
+ unsigned page_idx;
+ struct pagevec pvec;
+
+ pagevec_init(&pvec, 0);
+ for (page_idx = 0; page_idx < nr_pages; page_idx++) {
+ struct page *page = list_entry(pages->prev, struct page, lru);
+
+ prefetchw(&page->flags);
+ list_del(&page->lru);
+ /*
+ * what we want to do here is call add_to_page_cache_lru,
+ * but that isn't exported, so we reproduce it here
+ */
+ if (!add_to_page_cache(page, mapping,
+ page->index, GFP_KERNEL)) {
+
+ /* open coding of lru_cache_add, also not exported */
+ page_cache_get(page);
+ if (!pagevec_add(&pvec, page))
+ __pagevec_lru_add(&pvec);
+ __extent_read_full_page(tree, page, get_extent, &bio);
+ }
+ page_cache_release(page);
+ }
+ if (pagevec_count(&pvec))
+ __pagevec_lru_add(&pvec);
+ BUG_ON(!list_empty(pages));
+ if (bio)
+ submit_one_bio(READ, bio);
+ return 0;
+}
+EXPORT_SYMBOL(extent_readpages);
+
+/*
+ * basic invalidatepage code, this waits on any locked or writeback
+ * ranges corresponding to the page, and then deletes any extent state
+ * records from the tree
+ */
+int extent_invalidatepage(struct extent_io_tree *tree,
+ struct page *page, unsigned long offset)
+{
+ u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+ size_t blocksize = page->mapping->host->i_sb->s_blocksize;
+
+ start += (offset + blocksize -1) & ~(blocksize - 1);
+ if (start > end)
+ return 0;
+
+ lock_extent(tree, start, end, GFP_NOFS);
+ wait_on_extent_writeback(tree, start, end);
+ clear_extent_bit(tree, start, end,
+ EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
+ 1, 1, GFP_NOFS);
+ return 0;
+}
+EXPORT_SYMBOL(extent_invalidatepage);
+
+/*
+ * simple commit_write call, set_range_dirty is used to mark both
+ * the pages and the extent records as dirty
+ */
+int extent_commit_write(struct extent_io_tree *tree,
+ struct inode *inode, struct page *page,
+ unsigned from, unsigned to)
+{
+ loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+
+ set_page_extent_mapped(page);
+ set_page_dirty(page);
+
+ if (pos > inode->i_size) {
+ i_size_write(inode, pos);
+ mark_inode_dirty(inode);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(extent_commit_write);
+
+int extent_prepare_write(struct extent_io_tree *tree,
+ struct inode *inode, struct page *page,
+ unsigned from, unsigned to, get_extent_t *get_extent)
+{
+ u64 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
+ u64 block_start;
+ u64 orig_block_start;
+ u64 block_end;
+ u64 cur_end;
+ struct extent_map *em;
+ unsigned blocksize = 1 << inode->i_blkbits;
+ size_t page_offset = 0;
+ size_t block_off_start;
+ size_t block_off_end;
+ int err = 0;
+ int iocount = 0;
+ int ret = 0;
+ int isnew;
+
+ set_page_extent_mapped(page);
+
+ block_start = (page_start + from) & ~((u64)blocksize - 1);
+ block_end = (page_start + to - 1) | (blocksize - 1);
+ orig_block_start = block_start;
+
+ lock_extent(tree, page_start, page_end, GFP_NOFS);
+ while(block_start <= block_end) {
+ em = get_extent(inode, page, page_offset, block_start,
+ block_end - block_start + 1, 1);
+ if (IS_ERR(em) || !em) {
+ goto err;
+ }
+ cur_end = min(block_end, extent_map_end(em) - 1);
+ block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
+ block_off_end = block_off_start + blocksize;
+ isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
+
+ if (!PageUptodate(page) && isnew &&
+ (block_off_end > to || block_off_start < from)) {
+ void *kaddr;
+
+ kaddr = kmap_atomic(page, KM_USER0);
+ if (block_off_end > to)
+ memset(kaddr + to, 0, block_off_end - to);
+ if (block_off_start < from)
+ memset(kaddr + block_off_start, 0,
+ from - block_off_start);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ }
+ if ((em->block_start != EXTENT_MAP_HOLE &&
+ em->block_start != EXTENT_MAP_INLINE) &&
+ !isnew && !PageUptodate(page) &&
+ (block_off_end > to || block_off_start < from) &&
+ !test_range_bit(tree, block_start, cur_end,
+ EXTENT_UPTODATE, 1)) {
+ u64 sector;
+ u64 extent_offset = block_start - em->start;
+ size_t iosize;
+ sector = (em->block_start + extent_offset) >> 9;
+ iosize = (cur_end - block_start + blocksize) &
+ ~((u64)blocksize - 1);
+ /*
+ * we've already got the extent locked, but we
+ * need to split the state such that our end_bio
+ * handler can clear the lock.
+ */
+ set_extent_bit(tree, block_start,
+ block_start + iosize - 1,
+ EXTENT_LOCKED, 0, NULL, GFP_NOFS);
+ ret = submit_extent_page(READ, tree, page,
+ sector, iosize, page_offset, em->bdev,
+ NULL, 1,
+ end_bio_extent_preparewrite);
+ iocount++;
+ block_start = block_start + iosize;
+ } else {
+ set_extent_uptodate(tree, block_start, cur_end,
+ GFP_NOFS);
+ unlock_extent(tree, block_start, cur_end, GFP_NOFS);
+ block_start = cur_end + 1;
+ }
+ page_offset = block_start & (PAGE_CACHE_SIZE - 1);
+ free_extent_map(em);
+ }
+ if (iocount) {
+ wait_extent_bit(tree, orig_block_start,
+ block_end, EXTENT_LOCKED);
+ }
+ check_page_uptodate(tree, page);
+err:
+ /* FIXME, zero out newly allocated blocks on error */
+ return err;
+}
+EXPORT_SYMBOL(extent_prepare_write);
+
+/*
+ * a helper for releasepage. As long as there are no locked extents
+ * in the range corresponding to the page, both state records and extent
+ * map records are removed
+ */
+int try_release_extent_mapping(struct extent_map_tree *map,
+ struct extent_io_tree *tree, struct page *page)
+{
+ struct extent_map *em;
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+ u64 orig_start = start;
+ int ret = 1;
+
+ while (start <= end) {
+ spin_lock(&map->lock);
+ em = lookup_extent_mapping(map, start, end);
+ if (!em || IS_ERR(em)) {
+ spin_unlock(&map->lock);
+ break;
+ }
+ if (!test_range_bit(tree, em->start, extent_map_end(em) - 1,
+ EXTENT_LOCKED, 0)) {
+ remove_extent_mapping(map, em);
+ /* once for the rb tree */
+ free_extent_map(em);
+ }
+ start = extent_map_end(em);
+ spin_unlock(&map->lock);
+
+ /* once for us */
+ free_extent_map(em);
+ }
+ if (test_range_bit(tree, orig_start, end, EXTENT_LOCKED, 0))
+ ret = 0;
+ else
+ clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,
+ 1, 1, GFP_NOFS);
+ return ret;
+}
+EXPORT_SYMBOL(try_release_extent_mapping);
+
+sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
+ get_extent_t *get_extent)
+{
+ struct inode *inode = mapping->host;
+ u64 start = iblock << inode->i_blkbits;
+ sector_t sector = 0;
+ struct extent_map *em;
+
+ em = get_extent(inode, NULL, 0, start, (1 << inode->i_blkbits), 0);
+ if (!em || IS_ERR(em))
+ return 0;
+
+ if (em->block_start == EXTENT_MAP_INLINE ||
+ em->block_start == EXTENT_MAP_HOLE)
+ goto out;
+
+ sector = (em->block_start + start - em->start) >> inode->i_blkbits;
+printk("bmap finds %Lu %Lu block %Lu\n", em->start, em->len, em->block_start);
+out:
+ free_extent_map(em);
+ return sector;
+}
+
+static int add_lru(struct extent_io_tree *tree, struct extent_buffer *eb)
+{
+ if (list_empty(&eb->lru)) {
+ extent_buffer_get(eb);
+ list_add(&eb->lru, &tree->buffer_lru);
+ tree->lru_size++;
+ if (tree->lru_size >= BUFFER_LRU_MAX) {
+ struct extent_buffer *rm;
+ rm = list_entry(tree->buffer_lru.prev,
+ struct extent_buffer, lru);
+ tree->lru_size--;
+ list_del_init(&rm->lru);
+ free_extent_buffer(rm);
+ }
+ } else
+ list_move(&eb->lru, &tree->buffer_lru);
+ return 0;
+}
+static struct extent_buffer *find_lru(struct extent_io_tree *tree,
+ u64 start, unsigned long len)
+{
+ struct list_head *lru = &tree->buffer_lru;
+ struct list_head *cur = lru->next;
+ struct extent_buffer *eb;
+
+ if (list_empty(lru))
+ return NULL;
+
+ do {
+ eb = list_entry(cur, struct extent_buffer, lru);
+ if (eb->start == start && eb->len == len) {
+ extent_buffer_get(eb);
+ return eb;
+ }
+ cur = cur->next;
+ } while (cur != lru);
+ return NULL;
+}
+
+static inline unsigned long num_extent_pages(u64 start, u64 len)
+{
+ return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
+ (start >> PAGE_CACHE_SHIFT);
+}
+
+static inline struct page *extent_buffer_page(struct extent_buffer *eb,
+ unsigned long i)
+{
+ struct page *p;
+ struct address_space *mapping;
+
+ if (i == 0)
+ return eb->first_page;
+ i += eb->start >> PAGE_CACHE_SHIFT;
+ mapping = eb->first_page->mapping;
+ read_lock_irq(&mapping->tree_lock);
+ p = radix_tree_lookup(&mapping->page_tree, i);
+ read_unlock_irq(&mapping->tree_lock);
+ return p;
+}
+
+static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
+ u64 start,
+ unsigned long len,
+ gfp_t mask)
+{
+ struct extent_buffer *eb = NULL;
+
+ spin_lock(&tree->lru_lock);
+ eb = find_lru(tree, start, len);
+ spin_unlock(&tree->lru_lock);
+ if (eb) {
+ return eb;
+ }
+
+ eb = kmem_cache_zalloc(extent_buffer_cache, mask);
+ INIT_LIST_HEAD(&eb->lru);
+ eb->start = start;
+ eb->len = len;
+ atomic_set(&eb->refs, 1);
+
+ return eb;
+}
+
+static void __free_extent_buffer(struct extent_buffer *eb)
+{
+ kmem_cache_free(extent_buffer_cache, eb);
+}
+
+struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
+ u64 start, unsigned long len,
+ struct page *page0,
+ gfp_t mask)
+{
+ unsigned long num_pages = num_extent_pages(start, len);
+ unsigned long i;
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ struct extent_buffer *eb;
+ struct page *p;
+ struct address_space *mapping = tree->mapping;
+ int uptodate = 1;
+
+ eb = __alloc_extent_buffer(tree, start, len, mask);
+ if (!eb || IS_ERR(eb))
+ return NULL;
+
+ if (eb->flags & EXTENT_BUFFER_FILLED)
+ goto lru_add;
+
+ if (page0) {
+ eb->first_page = page0;
+ i = 1;
+ index++;
+ page_cache_get(page0);
+ mark_page_accessed(page0);
+ set_page_extent_mapped(page0);
+ WARN_ON(!PageUptodate(page0));
+ set_page_extent_head(page0, len);
+ } else {
+ i = 0;
+ }
+ for (; i < num_pages; i++, index++) {
+ p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
+ if (!p) {
+ WARN_ON(1);
+ goto fail;
+ }
+ set_page_extent_mapped(p);
+ mark_page_accessed(p);
+ if (i == 0) {
+ eb->first_page = p;
+ set_page_extent_head(p, len);
+ } else {
+ set_page_private(p, EXTENT_PAGE_PRIVATE);
+ }
+ if (!PageUptodate(p))
+ uptodate = 0;
+ unlock_page(p);
+ }
+ if (uptodate)
+ eb->flags |= EXTENT_UPTODATE;
+ eb->flags |= EXTENT_BUFFER_FILLED;
+
+lru_add:
+ spin_lock(&tree->lru_lock);
+ add_lru(tree, eb);
+ spin_unlock(&tree->lru_lock);
+ return eb;
+
+fail:
+ spin_lock(&tree->lru_lock);
+ list_del_init(&eb->lru);
+ spin_unlock(&tree->lru_lock);
+ if (!atomic_dec_and_test(&eb->refs))
+ return NULL;
+ for (index = 1; index < i; index++) {
+ page_cache_release(extent_buffer_page(eb, index));
+ }
+ if (i > 0)
+ page_cache_release(extent_buffer_page(eb, 0));
+ __free_extent_buffer(eb);
+ return NULL;
+}
+EXPORT_SYMBOL(alloc_extent_buffer);
+
+struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
+ u64 start, unsigned long len,
+ gfp_t mask)
+{
+ unsigned long num_pages = num_extent_pages(start, len);
+ unsigned long i;
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ struct extent_buffer *eb;
+ struct page *p;
+ struct address_space *mapping = tree->mapping;
+ int uptodate = 1;
+
+ eb = __alloc_extent_buffer(tree, start, len, mask);
+ if (!eb || IS_ERR(eb))
+ return NULL;
+
+ if (eb->flags & EXTENT_BUFFER_FILLED)
+ goto lru_add;
+
+ for (i = 0; i < num_pages; i++, index++) {
+ p = find_lock_page(mapping, index);
+ if (!p) {
+ goto fail;
+ }
+ set_page_extent_mapped(p);
+ mark_page_accessed(p);
+
+ if (i == 0) {
+ eb->first_page = p;
+ set_page_extent_head(p, len);
+ } else {
+ set_page_private(p, EXTENT_PAGE_PRIVATE);
+ }
+
+ if (!PageUptodate(p))
+ uptodate = 0;
+ unlock_page(p);
+ }
+ if (uptodate)
+ eb->flags |= EXTENT_UPTODATE;
+ eb->flags |= EXTENT_BUFFER_FILLED;
+
+lru_add:
+ spin_lock(&tree->lru_lock);
+ add_lru(tree, eb);
+ spin_unlock(&tree->lru_lock);
+ return eb;
+fail:
+ spin_lock(&tree->lru_lock);
+ list_del_init(&eb->lru);
+ spin_unlock(&tree->lru_lock);
+ if (!atomic_dec_and_test(&eb->refs))
+ return NULL;
+ for (index = 1; index < i; index++) {
+ page_cache_release(extent_buffer_page(eb, index));
+ }
+ if (i > 0)
+ page_cache_release(extent_buffer_page(eb, 0));
+ __free_extent_buffer(eb);
+ return NULL;
+}
+EXPORT_SYMBOL(find_extent_buffer);
+
+void free_extent_buffer(struct extent_buffer *eb)
+{
+ unsigned long i;
+ unsigned long num_pages;
+
+ if (!eb)
+ return;
+
+ if (!atomic_dec_and_test(&eb->refs))
+ return;
+
+ WARN_ON(!list_empty(&eb->lru));
+ num_pages = num_extent_pages(eb->start, eb->len);
+
+ for (i = 1; i < num_pages; i++) {
+ page_cache_release(extent_buffer_page(eb, i));
+ }
+ page_cache_release(extent_buffer_page(eb, 0));
+ __free_extent_buffer(eb);
+}
+EXPORT_SYMBOL(free_extent_buffer);
+
+int clear_extent_buffer_dirty(struct extent_io_tree *tree,
+ struct extent_buffer *eb)
+{
+ int set;
+ unsigned long i;
+ unsigned long num_pages;
+ struct page *page;
+
+ u64 start = eb->start;
+ u64 end = start + eb->len - 1;
+
+ set = clear_extent_dirty(tree, start, end, GFP_NOFS);
+ num_pages = num_extent_pages(eb->start, eb->len);
+
+ for (i = 0; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ lock_page(page);
+ if (i == 0)
+ set_page_extent_head(page, eb->len);
+ else
+ set_page_private(page, EXTENT_PAGE_PRIVATE);
+
+ /*
+ * if we're on the last page or the first page and the
+ * block isn't aligned on a page boundary, do extra checks
+ * to make sure we don't clean page that is partially dirty
+ */
+ if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
+ ((i == num_pages - 1) &&
+ ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
+ start = (u64)page->index << PAGE_CACHE_SHIFT;
+ end = start + PAGE_CACHE_SIZE - 1;
+ if (test_range_bit(tree, start, end,
+ EXTENT_DIRTY, 0)) {
+ unlock_page(page);
+ continue;
+ }
+ }
+ clear_page_dirty_for_io(page);
+ write_lock_irq(&page->mapping->tree_lock);
+ if (!PageDirty(page)) {
+ radix_tree_tag_clear(&page->mapping->page_tree,
+ page_index(page),
+ PAGECACHE_TAG_DIRTY);
+ }
+ write_unlock_irq(&page->mapping->tree_lock);
+ unlock_page(page);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(clear_extent_buffer_dirty);
+
+int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
+ struct extent_buffer *eb)
+{
+ return wait_on_extent_writeback(tree, eb->start,
+ eb->start + eb->len - 1);
+}
+EXPORT_SYMBOL(wait_on_extent_buffer_writeback);
+
+int set_extent_buffer_dirty(struct extent_io_tree *tree,
+ struct extent_buffer *eb)
+{
+ unsigned long i;
+ unsigned long num_pages;
+
+ num_pages = num_extent_pages(eb->start, eb->len);
+ for (i = 0; i < num_pages; i++) {
+ struct page *page = extent_buffer_page(eb, i);
+ /* writepage may need to do something special for the
+ * first page, we have to make sure page->private is
+ * properly set. releasepage may drop page->private
+ * on us if the page isn't already dirty.
+ */
+ if (i == 0) {
+ lock_page(page);
+ set_page_extent_head(page, eb->len);
+ } else if (PagePrivate(page) &&
+ page->private != EXTENT_PAGE_PRIVATE) {
+ lock_page(page);
+ set_page_extent_mapped(page);
+ unlock_page(page);
+ }
+ __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
+ if (i == 0)
+ unlock_page(page);
+ }
+ return set_extent_dirty(tree, eb->start,
+ eb->start + eb->len - 1, GFP_NOFS);
+}
+EXPORT_SYMBOL(set_extent_buffer_dirty);
+
+int set_extent_buffer_uptodate(struct extent_io_tree *tree,
+ struct extent_buffer *eb)
+{
+ unsigned long i;
+ struct page *page;
+ unsigned long num_pages;
+
+ num_pages = num_extent_pages(eb->start, eb->len);
+
+ set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
+ GFP_NOFS);
+ for (i = 0; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
+ ((i == num_pages - 1) &&
+ ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
+ check_page_uptodate(tree, page);
+ continue;
+ }
+ SetPageUptodate(page);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(set_extent_buffer_uptodate);
+
+int extent_buffer_uptodate(struct extent_io_tree *tree,
+ struct extent_buffer *eb)
+{
+ if (eb->flags & EXTENT_UPTODATE)
+ return 1;
+ return test_range_bit(tree, eb->start, eb->start + eb->len - 1,
+ EXTENT_UPTODATE, 1);
+}
+EXPORT_SYMBOL(extent_buffer_uptodate);
+
+int read_extent_buffer_pages(struct extent_io_tree *tree,
+ struct extent_buffer *eb,
+ u64 start,
+ int wait)
+{
+ unsigned long i;
+ unsigned long start_i;
+ struct page *page;
+ int err;
+ int ret = 0;
+ unsigned long num_pages;
+
+ if (eb->flags & EXTENT_UPTODATE)
+ return 0;
+
+ if (0 && test_range_bit(tree, eb->start, eb->start + eb->len - 1,
+ EXTENT_UPTODATE, 1)) {
+ return 0;
+ }
+
+ if (start) {
+ WARN_ON(start < eb->start);
+ start_i = (start >> PAGE_CACHE_SHIFT) -
+ (eb->start >> PAGE_CACHE_SHIFT);
+ } else {
+ start_i = 0;
+ }
+
+ num_pages = num_extent_pages(eb->start, eb->len);
+ for (i = start_i; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ if (PageUptodate(page)) {
+ continue;
+ }
+ if (!wait) {
+ if (TestSetPageLocked(page)) {
+ continue;
+ }
+ } else {
+ lock_page(page);
+ }
+ if (!PageUptodate(page)) {
+ err = page->mapping->a_ops->readpage(NULL, page);
+ if (err) {
+ ret = err;
+ }
+ } else {
+ unlock_page(page);
+ }
+ }
+
+ if (ret || !wait) {
+ return ret;
+ }
+
+ for (i = start_i; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ wait_on_page_locked(page);
+ if (!PageUptodate(page)) {
+ ret = -EIO;
+ }
+ }
+ if (!ret)
+ eb->flags |= EXTENT_UPTODATE;
+ return ret;
+}
+EXPORT_SYMBOL(read_extent_buffer_pages);
+
+void read_extent_buffer(struct extent_buffer *eb, void *dstv,
+ unsigned long start,
+ unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ char *dst = (char *)dstv;
+ size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+ unsigned long num_pages = num_extent_pages(eb->start, eb->len);
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+ while(len > 0) {
+ page = extent_buffer_page(eb, i);
+ if (!PageUptodate(page)) {
+ printk("page %lu not up to date i %lu, total %lu, len %lu\n", page->index, i, num_pages, eb->len);
+ WARN_ON(1);
+ }
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, (PAGE_CACHE_SIZE - offset));
+ kaddr = kmap_atomic(page, KM_USER1);
+ memcpy(dst, kaddr + offset, cur);
+ kunmap_atomic(kaddr, KM_USER1);
+
+ dst += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+EXPORT_SYMBOL(read_extent_buffer);
+
+int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
+ unsigned long min_len, char **token, char **map,
+ unsigned long *map_start,
+ unsigned long *map_len, int km)
+{
+ size_t offset = start & (PAGE_CACHE_SIZE - 1);
+ char *kaddr;
+ struct page *p;
+ size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+ unsigned long end_i = (start_offset + start + min_len - 1) >>
+ PAGE_CACHE_SHIFT;
+
+ if (i != end_i)
+ return -EINVAL;
+
+ if (i == 0) {
+ offset = start_offset;
+ *map_start = 0;
+ } else {
+ offset = 0;
+ *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
+ }
+ if (start + min_len > eb->len) {
+printk("bad mapping eb start %Lu len %lu, wanted %lu %lu\n", eb->start, eb->len, start, min_len);
+ WARN_ON(1);
+ }
+
+ p = extent_buffer_page(eb, i);
+ WARN_ON(!PageUptodate(p));
+ kaddr = kmap_atomic(p, km);
+ *token = kaddr;
+ *map = kaddr + offset;
+ *map_len = PAGE_CACHE_SIZE - offset;
+ return 0;
+}
+EXPORT_SYMBOL(map_private_extent_buffer);
+
+int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
+ unsigned long min_len,
+ char **token, char **map,
+ unsigned long *map_start,
+ unsigned long *map_len, int km)
+{
+ int err;
+ int save = 0;
+ if (eb->map_token) {
+ unmap_extent_buffer(eb, eb->map_token, km);
+ eb->map_token = NULL;
+ save = 1;
+ }
+ err = map_private_extent_buffer(eb, start, min_len, token, map,
+ map_start, map_len, km);
+ if (!err && save) {
+ eb->map_token = *token;
+ eb->kaddr = *map;
+ eb->map_start = *map_start;
+ eb->map_len = *map_len;
+ }
+ return err;
+}
+EXPORT_SYMBOL(map_extent_buffer);
+
+void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
+{
+ kunmap_atomic(token, km);
+}
+EXPORT_SYMBOL(unmap_extent_buffer);
+
+int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
+ unsigned long start,
+ unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ char *ptr = (char *)ptrv;
+ size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+ int ret = 0;
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+ while(len > 0) {
+ page = extent_buffer_page(eb, i);
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, (PAGE_CACHE_SIZE - offset));
+
+ kaddr = kmap_atomic(page, KM_USER0);
+ ret = memcmp(ptr, kaddr + offset, cur);
+ kunmap_atomic(kaddr, KM_USER0);
+ if (ret)
+ break;
+
+ ptr += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+ return ret;
+}
+EXPORT_SYMBOL(memcmp_extent_buffer);
+
+void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
+ unsigned long start, unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ char *src = (char *)srcv;
+ size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+ while(len > 0) {
+ page = extent_buffer_page(eb, i);
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, PAGE_CACHE_SIZE - offset);
+ kaddr = kmap_atomic(page, KM_USER1);
+ memcpy(kaddr + offset, src, cur);
+ kunmap_atomic(kaddr, KM_USER1);
+
+ src += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+EXPORT_SYMBOL(write_extent_buffer);
+
+void memset_extent_buffer(struct extent_buffer *eb, char c,
+ unsigned long start, unsigned long len)
+{
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+
+ WARN_ON(start > eb->len);
+ WARN_ON(start + len > eb->start + eb->len);
+
+ offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+ while(len > 0) {
+ page = extent_buffer_page(eb, i);
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, PAGE_CACHE_SIZE - offset);
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + offset, c, cur);
+ kunmap_atomic(kaddr, KM_USER0);
+
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+EXPORT_SYMBOL(memset_extent_buffer);
+
+void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
+ unsigned long dst_offset, unsigned long src_offset,
+ unsigned long len)
+{
+ u64 dst_len = dst->len;
+ size_t cur;
+ size_t offset;
+ struct page *page;
+ char *kaddr;
+ size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
+
+ WARN_ON(src->len != dst_len);
+
+ offset = (start_offset + dst_offset) &
+ ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+ while(len > 0) {
+ page = extent_buffer_page(dst, i);
+ WARN_ON(!PageUptodate(page));
+
+ cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
+
+ kaddr = kmap_atomic(page, KM_USER0);
+ read_extent_buffer(src, kaddr + offset, src_offset, cur);
+ kunmap_atomic(kaddr, KM_USER0);
+
+ src_offset += cur;
+ len -= cur;
+ offset = 0;
+ i++;
+ }
+}
+EXPORT_SYMBOL(copy_extent_buffer);
+
+static void move_pages(struct page *dst_page, struct page *src_page,
+ unsigned long dst_off, unsigned long src_off,
+ unsigned long len)
+{
+ char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
+ if (dst_page == src_page) {
+ memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
+ } else {
+ char *src_kaddr = kmap_atomic(src_page, KM_USER1);
+ char *p = dst_kaddr + dst_off + len;
+ char *s = src_kaddr + src_off + len;
+
+ while (len--)
+ *--p = *--s;
+
+ kunmap_atomic(src_kaddr, KM_USER1);
+ }
+ kunmap_atomic(dst_kaddr, KM_USER0);
+}
+
+static void copy_pages(struct page *dst_page, struct page *src_page,
+ unsigned long dst_off, unsigned long src_off,
+ unsigned long len)
+{
+ char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
+ char *src_kaddr;
+
+ if (dst_page != src_page)
+ src_kaddr = kmap_atomic(src_page, KM_USER1);
+ else
+ src_kaddr = dst_kaddr;
+
+ memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
+ kunmap_atomic(dst_kaddr, KM_USER0);
+ if (dst_page != src_page)
+ kunmap_atomic(src_kaddr, KM_USER1);
+}
+
+void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
+ unsigned long src_offset, unsigned long len)
+{
+ size_t cur;
+ size_t dst_off_in_page;
+ size_t src_off_in_page;
+ size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long dst_i;
+ unsigned long src_i;
+
+ if (src_offset + len > dst->len) {
+ printk("memmove bogus src_offset %lu move len %lu len %lu\n",
+ src_offset, len, dst->len);
+ BUG_ON(1);
+ }
+ if (dst_offset + len > dst->len) {
+ printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
+ dst_offset, len, dst->len);
+ BUG_ON(1);
+ }
+
+ while(len > 0) {
+ dst_off_in_page = (start_offset + dst_offset) &
+ ((unsigned long)PAGE_CACHE_SIZE - 1);
+ src_off_in_page = (start_offset + src_offset) &
+ ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+ dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
+ src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
+
+ cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
+ src_off_in_page));
+ cur = min_t(unsigned long, cur,
+ (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
+
+ copy_pages(extent_buffer_page(dst, dst_i),
+ extent_buffer_page(dst, src_i),
+ dst_off_in_page, src_off_in_page, cur);
+
+ src_offset += cur;
+ dst_offset += cur;
+ len -= cur;
+ }
+}
+EXPORT_SYMBOL(memcpy_extent_buffer);
+
+void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
+ unsigned long src_offset, unsigned long len)
+{
+ size_t cur;
+ size_t dst_off_in_page;
+ size_t src_off_in_page;
+ unsigned long dst_end = dst_offset + len - 1;
+ unsigned long src_end = src_offset + len - 1;
+ size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
+ unsigned long dst_i;
+ unsigned long src_i;
+
+ if (src_offset + len > dst->len) {
+ printk("memmove bogus src_offset %lu move len %lu len %lu\n",
+ src_offset, len, dst->len);
+ BUG_ON(1);
+ }
+ if (dst_offset + len > dst->len) {
+ printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
+ dst_offset, len, dst->len);
+ BUG_ON(1);
+ }
+ if (dst_offset < src_offset) {
+ memcpy_extent_buffer(dst, dst_offset, src_offset, len);
+ return;
+ }
+ while(len > 0) {
+ dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
+ src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
+
+ dst_off_in_page = (start_offset + dst_end) &
+ ((unsigned long)PAGE_CACHE_SIZE - 1);
+ src_off_in_page = (start_offset + src_end) &
+ ((unsigned long)PAGE_CACHE_SIZE - 1);
+
+ cur = min_t(unsigned long, len, src_off_in_page + 1);
+ cur = min(cur, dst_off_in_page + 1);
+ move_pages(extent_buffer_page(dst, dst_i),
+ extent_buffer_page(dst, src_i),
+ dst_off_in_page - cur + 1,
+ src_off_in_page - cur + 1, cur);
+
+ dst_end -= cur;
+ src_end -= cur;
+ len -= cur;
+ }
+}
+EXPORT_SYMBOL(memmove_extent_buffer);