extent_io includes two interfaces. Each one should live in its own
file, but for now they share a single one.
extent_state: These track state bits across a range of bytes instead of
a single page. So, btrfs can say bytes 0-1MB are marked for delalloc, and
do searches based on the ranges. An rbtree is used to track state per
inode.
This code also implements readpages and writepages based on the extent_state
code. No buffer heads are used, even as temporary containers for IO. This
only works with page sized IO today.
Signed-off-by: Chris Mason <chris.mason@xxxxxxxxxx>
--- /dev/null 2008-06-10 15:56:50.000000000 -0400
+++ b/fs/btrfs/extent_io.c 2009-01-08 10:10:26.609514565 -0500
@@ -0,0 +1,2795 @@
+#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"
+#include "compat.h"
+#include "ctree.h"
+#include "btrfs_inode.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 LIST_HEAD(buffers);
+static LIST_HEAD(states);
+
+#define LEAK_DEBUG 0
+#ifdef LEAK_DEBUG
+static DEFINE_SPINLOCK(leak_lock);
+#endif
+
+#define BUFFER_LRU_MAX 64
+
+struct tree_entry {
+ u64 start;
+ u64 end;
+ struct rb_node rb_node;
+};
+
+struct extent_page_data {
+ struct bio *bio;
+ struct extent_io_tree *tree;
+ get_extent_t *get_extent;
+
+ /* tells writepage not to lock the state bits for this range
+ * it still does the unlocking
+ */
+ int extent_locked;
+};
+
+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;
+
+ 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, leak_list);
+ printk(KERN_ERR "btrfs state leak: start %llu end %llu "
+ "state %lu in tree %p refs %d\n",
+ (unsigned long long)state->start,
+ (unsigned long long)state->end,
+ state->state, state->tree, atomic_read(&state->refs));
+ list_del(&state->leak_list);
+ kmem_cache_free(extent_state_cache, state);
+
+ }
+
+ if (extent_state_cache)
+ kmem_cache_destroy(extent_state_cache);
+}
+
+void extent_io_tree_init(struct extent_io_tree *tree,
+ struct address_space *mapping, gfp_t mask)
+{
+ tree->state.rb_node = NULL;
+ tree->buffer.rb_node = NULL;
+ tree->ops = NULL;
+ tree->dirty_bytes = 0;
+ spin_lock_init(&tree->lock);
+ spin_lock_init(&tree->buffer_lock);
+ tree->mapping = mapping;
+}
+
+static struct extent_state *alloc_extent_state(gfp_t mask)
+{
+ struct extent_state *state;
+#ifdef LEAK_DEBUG
+ unsigned long flags;
+#endif
+
+ state = kmem_cache_alloc(extent_state_cache, mask);
+ if (!state)
+ return state;
+ state->state = 0;
+ state->private = 0;
+ state->tree = NULL;
+#ifdef LEAK_DEBUG
+ spin_lock_irqsave(&leak_lock, flags);
+ list_add(&state->leak_list, &states);
+ spin_unlock_irqrestore(&leak_lock, flags);
+#endif
+ atomic_set(&state->refs, 1);
+ init_waitqueue_head(&state->wq);
+ return state;
+}
+
+static void free_extent_state(struct extent_state *state)
+{
+ if (!state)
+ return;
+ if (atomic_dec_and_test(&state->refs)) {
+#ifdef LEAK_DEBUG
+ unsigned long flags;
+#endif
+ WARN_ON(state->tree);
+#ifdef LEAK_DEBUG
+ spin_lock_irqsave(&leak_lock, flags);
+ list_del(&state->leak_list);
+ spin_unlock_irqrestore(&leak_lock, flags);
+#endif
+ kmem_cache_free(extent_state_cache, 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);
+ rb_link_node(node, parent, p);
+ rb_insert_color(node, root);
+ return NULL;
+}
+
+static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
+ struct rb_node **prev_ret,
+ struct rb_node **next_ret)
+{
+ struct rb_root *root = &tree->state;
+ 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 extent_io_tree *tree,
+ u64 offset)
+{
+ struct rb_node *prev = NULL;
+ struct rb_node *ret;
+
+ ret = __etree_search(tree, 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 | EXTENT_BOUNDARY))
+ 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->tree = NULL;
+ 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->tree = NULL;
+ rb_erase(&state->rb_node, &tree->state);
+ free_extent_state(state);
+ }
+ }
+ return 0;
+}
+
+static void set_state_cb(struct extent_io_tree *tree,
+ struct extent_state *state,
+ unsigned long bits)
+{
+ if (tree->ops && tree->ops->set_bit_hook) {
+ tree->ops->set_bit_hook(tree->mapping->host, state->start,
+ state->end, state->state, bits);
+ }
+}
+
+static void clear_state_cb(struct extent_io_tree *tree,
+ struct extent_state *state,
+ unsigned long bits)
+{
+ if (tree->ops && tree->ops->clear_bit_hook) {
+ tree->ops->clear_bit_hook(tree->mapping->host, state->start,
+ state->end, state->state, bits);
+ }
+}
+
+/*
+ * 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(KERN_ERR "btrfs end < start %llu %llu\n",
+ (unsigned long long)end,
+ (unsigned long long)start);
+ WARN_ON(1);
+ }
+ if (bits & EXTENT_DIRTY)
+ tree->dirty_bytes += end - start + 1;
+ set_state_cb(tree, state, bits);
+ 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(KERN_ERR "btrfs found node %llu %llu on insert of "
+ "%llu %llu\n", (unsigned long long)found->start,
+ (unsigned long long)found->end,
+ (unsigned long long)start, (unsigned long long)end);
+ free_extent_state(state);
+ return -EEXIST;
+ }
+ state->tree = tree;
+ 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);
+ free_extent_state(prealloc);
+ return -EEXIST;
+ }
+ prealloc->tree = tree;
+ 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;
+ }
+ clear_state_cb(tree, state, bits);
+ state->state &= ~bits;
+ if (wake)
+ wake_up(&state->wq);
+ if (delete || state->state == 0) {
+ if (state->tree) {
+ clear_state_cb(tree, state, state->state);
+ rb_erase(&state->rb_node, &tree->state);
+ state->tree = NULL;
+ 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;
+ int err;
+ int set = 0;
+
+again:
+ if (!prealloc && (mask & __GFP_WAIT)) {
+ prealloc = alloc_extent_state(mask);
+ if (!prealloc)
+ return -ENOMEM;
+ }
+
+ spin_lock(&tree->lock);
+ /*
+ * this search will find the extents that end after
+ * our range starts
+ */
+ node = tree_search(tree, 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) {
+ if (!prealloc)
+ prealloc = alloc_extent_state(GFP_ATOMIC);
+ 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) {
+ if (!prealloc)
+ prealloc = alloc_extent_state(GFP_ATOMIC);
+ 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:
+ spin_unlock(&tree->lock);
+ if (prealloc)
+ free_extent_state(prealloc);
+
+ return set;
+
+search_again:
+ if (start > end)
+ goto out;
+ spin_unlock(&tree->lock);
+ if (mask & __GFP_WAIT)
+ cond_resched();
+ goto again;
+}
+
+static int wait_on_state(struct extent_io_tree *tree,
+ struct extent_state *state)
+ __releases(tree->lock)
+ __acquires(tree->lock)
+{
+ DEFINE_WAIT(wait);
+ prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&tree->lock);
+ schedule();
+ spin_lock(&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;
+
+ spin_lock(&tree->lock);
+again:
+ while (1) {
+ /*
+ * this search will find all the extents that end after
+ * our range starts
+ */
+ node = tree_search(tree, 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()) {
+ spin_unlock(&tree->lock);
+ cond_resched();
+ spin_lock(&tree->lock);
+ }
+ }
+out:
+ spin_unlock(&tree->lock);
+ return 0;
+}
+
+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;
+ }
+ set_state_cb(tree, state, bits);
+ 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.
+ */
+static 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;
+ 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;
+ }
+
+ spin_lock(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, 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:
+ spin_unlock(&tree->lock);
+ if (prealloc)
+ free_extent_state(prealloc);
+
+ return err;
+
+search_again:
+ if (start > end)
+ goto out;
+ spin_unlock(&tree->lock);
+ if (mask & __GFP_WAIT)
+ cond_resched();
+ goto again;
+}
+
+/* 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);
+}
+
+int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return set_extent_bit(tree, start, end, EXTENT_ORDERED, 0, NULL, mask);
+}
+
+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);
+}
+
+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);
+}
+
+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);
+}
+
+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);
+}
+
+int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end, EXTENT_ORDERED, 1, 0, mask);
+}
+
+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);
+}
+
+static 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);
+}
+
+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);
+}
+
+static 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);
+}
+
+static 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);
+}
+
+static 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);
+}
+
+int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
+{
+ return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
+}
+
+/*
+ * either insert or lock state struct between start and end use mask to tell
+ * us if waiting is desired.
+ */
+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;
+}
+
+int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ int err;
+ u64 failed_start;
+
+ err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
+ &failed_start, mask);
+ if (err == -EEXIST) {
+ if (failed_start > start)
+ clear_extent_bit(tree, start, failed_start - 1,
+ EXTENT_LOCKED, 1, 0, mask);
+ return 0;
+ }
+ return 1;
+}
+
+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);
+}
+
+/*
+ * 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;
+}
+
+/*
+ * helper function to set both pages and extents in the tree writeback
+ */
+static 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;
+}
+
+/*
+ * find the first offset in the io tree with 'bits' set. zero is
+ * returned if we find something, and *start_ret and *end_ret are
+ * set to reflect the state struct that was found.
+ *
+ * If nothing was found, 1 is returned, < 0 on error
+ */
+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;
+
+ spin_lock(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, start);
+ if (!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:
+ spin_unlock(&tree->lock);
+ return ret;
+}
+
+/* find the first state struct with 'bits' set after 'start', and
+ * return it. tree->lock must be held. NULL will returned if
+ * nothing was found after 'start'
+ */
+struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
+ u64 start, int bits)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, start);
+ if (!node)
+ goto out;
+
+ while (1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (state->end >= start && (state->state & bits))
+ return state;
+
+ node = rb_next(node);
+ if (!node)
+ break;
+ }
+out:
+ return NULL;
+}
+
+/*
+ * find a contiguous range of bytes in the file marked as delalloc, not
+ * more than 'max_bytes'. start and end are used to return the range,
+ *
+ * 1 is returned if we find something, 0 if nothing was in the tree
+ */
+static noinline u64 find_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;
+
+ spin_lock(&tree->lock);
+
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, cur_start);
+ if (!node) {
+ if (!found)
+ *end = (u64)-1;
+ goto out;
+ }
+
+ while (1) {
+ state = rb_entry(node, struct extent_state, rb_node);
+ if (found && (state->start != cur_start ||
+ (state->state & EXTENT_BOUNDARY))) {
+ goto out;
+ }
+ if (!(state->state & EXTENT_DELALLOC)) {
+ if (!found)
+ *end = state->end;
+ goto out;
+ }
+ 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:
+ spin_unlock(&tree->lock);
+ return found;
+}
+
+static noinline int __unlock_for_delalloc(struct inode *inode,
+ struct page *locked_page,
+ u64 start, u64 end)
+{
+ int ret;
+ struct page *pages[16];
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ unsigned long nr_pages = end_index - index + 1;
+ int i;
+
+ if (index == locked_page->index && end_index == index)
+ return 0;
+
+ while (nr_pages > 0) {
+ ret = find_get_pages_contig(inode->i_mapping, index,
+ min_t(unsigned long, nr_pages,
+ ARRAY_SIZE(pages)), pages);
+ for (i = 0; i < ret; i++) {
+ if (pages[i] != locked_page)
+ unlock_page(pages[i]);
+ page_cache_release(pages[i]);
+ }
+ nr_pages -= ret;
+ index += ret;
+ cond_resched();
+ }
+ return 0;
+}
+
+static noinline int lock_delalloc_pages(struct inode *inode,
+ struct page *locked_page,
+ u64 delalloc_start,
+ u64 delalloc_end)
+{
+ unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
+ unsigned long start_index = index;
+ unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
+ unsigned long pages_locked = 0;
+ struct page *pages[16];
+ unsigned long nrpages;
+ int ret;
+ int i;
+
+ /* the caller is responsible for locking the start index */
+ if (index == locked_page->index && index == end_index)
+ return 0;
+
+ /* skip the page at the start index */
+ nrpages = end_index - index + 1;
+ while (nrpages > 0) {
+ ret = find_get_pages_contig(inode->i_mapping, index,
+ min_t(unsigned long,
+ nrpages, ARRAY_SIZE(pages)), pages);
+ if (ret == 0) {
+ ret = -EAGAIN;
+ goto done;
+ }
+ /* now we have an array of pages, lock them all */
+ for (i = 0; i < ret; i++) {
+ /*
+ * the caller is taking responsibility for
+ * locked_page
+ */
+ if (pages[i] != locked_page) {
+ lock_page(pages[i]);
+ if (!PageDirty(pages[i]) ||
+ pages[i]->mapping != inode->i_mapping) {
+ ret = -EAGAIN;
+ unlock_page(pages[i]);
+ page_cache_release(pages[i]);
+ goto done;
+ }
+ }
+ page_cache_release(pages[i]);
+ pages_locked++;
+ }
+ nrpages -= ret;
+ index += ret;
+ cond_resched();
+ }
+ ret = 0;
+done:
+ if (ret && pages_locked) {
+ __unlock_for_delalloc(inode, locked_page,
+ delalloc_start,
+ ((u64)(start_index + pages_locked - 1)) <<
+ PAGE_CACHE_SHIFT);
+ }
+ return ret;
+}
+
+/*
+ * find a contiguous range of bytes in the file marked as delalloc, not
+ * more than 'max_bytes'. start and end are used to return the range,
+ *
+ * 1 is returned if we find something, 0 if nothing was in the tree
+ */
+static noinline u64 find_lock_delalloc_range(struct inode *inode,
+ struct extent_io_tree *tree,
+ struct page *locked_page,
+ u64 *start, u64 *end,
+ u64 max_bytes)
+{
+ u64 delalloc_start;
+ u64 delalloc_end;
+ u64 found;
+ int ret;
+ int loops = 0;
+
+again:
+ /* step one, find a bunch of delalloc bytes starting at start */
+ delalloc_start = *start;
+ delalloc_end = 0;
+ found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
+ max_bytes);
+ if (!found || delalloc_end <= *start) {
+ *start = delalloc_start;
+ *end = delalloc_end;
+ return found;
+ }
+
+ /*
+ * start comes from the offset of locked_page. We have to lock
+ * pages in order, so we can't process delalloc bytes before
+ * locked_page
+ */
+ if (delalloc_start < *start)
+ delalloc_start = *start;
+
+ /*
+ * make sure to limit the number of pages we try to lock down
+ * if we're looping.
+ */
+ if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
+ delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
+
+ /* step two, lock all the pages after the page that has start */
+ ret = lock_delalloc_pages(inode, locked_page,
+ delalloc_start, delalloc_end);
+ if (ret == -EAGAIN) {
+ /* some of the pages are gone, lets avoid looping by
+ * shortening the size of the delalloc range we're searching
+ */
+ if (!loops) {
+ unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
+ max_bytes = PAGE_CACHE_SIZE - offset;
+ loops = 1;
+ goto again;
+ } else {
+ found = 0;
+ goto out_failed;
+ }
+ }
+ BUG_ON(ret);
+
+ /* step three, lock the state bits for the whole range */
+ lock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
+
+ /* then test to make sure it is all still delalloc */
+ ret = test_range_bit(tree, delalloc_start, delalloc_end,
+ EXTENT_DELALLOC, 1);
+ if (!ret) {
+ unlock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
+ __unlock_for_delalloc(inode, locked_page,
+ delalloc_start, delalloc_end);
+ cond_resched();
+ goto again;
+ }
+ *start = delalloc_start;
+ *end = delalloc_end;
+out_failed:
+ return found;
+}
+
+int extent_clear_unlock_delalloc(struct inode *inode,
+ struct extent_io_tree *tree,
+ u64 start, u64 end, struct page *locked_page,
+ int unlock_pages,
+ int clear_unlock,
+ int clear_delalloc, int clear_dirty,
+ int set_writeback,
+ int end_writeback)
+{
+ int ret;
+ struct page *pages[16];
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ unsigned long nr_pages = end_index - index + 1;
+ int i;
+ int clear_bits = 0;
+
+ if (clear_unlock)
+ clear_bits |= EXTENT_LOCKED;
+ if (clear_dirty)
+ clear_bits |= EXTENT_DIRTY;
+
+ if (clear_delalloc)
+ clear_bits |= EXTENT_DELALLOC;
+
+ clear_extent_bit(tree, start, end, clear_bits, 1, 0, GFP_NOFS);
+ if (!(unlock_pages || clear_dirty || set_writeback || end_writeback))
+ return 0;
+
+ while (nr_pages > 0) {
+ ret = find_get_pages_contig(inode->i_mapping, index,
+ min_t(unsigned long,
+ nr_pages, ARRAY_SIZE(pages)), pages);
+ for (i = 0; i < ret; i++) {
+ if (pages[i] == locked_page) {
+ page_cache_release(pages[i]);
+ continue;
+ }
+ if (clear_dirty)
+ clear_page_dirty_for_io(pages[i]);
+ if (set_writeback)
+ set_page_writeback(pages[i]);
+ if (end_writeback)
+ end_page_writeback(pages[i]);
+ if (unlock_pages)
+ unlock_page(pages[i]);
+ page_cache_release(pages[i]);
+ }
+ nr_pages -= ret;
+ index += ret;
+ cond_resched();
+ }
+ return 0;
+}
+
+/*
+ * count the number of bytes in the tree that have a given bit(s)
+ * set. This can be fairly slow, except for EXTENT_DIRTY which is
+ * cached. The total number found is returned.
+ */
+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) {
+ WARN_ON(1);
+ return 0;
+ }
+
+ spin_lock(&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, cur_start);
+ if (!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:
+ spin_unlock(&tree->lock);
+ return total_bytes;
+}
+
+#if 0
+/*
+ * helper function to lock both pages and extents in the tree.
+ * pages must be locked first.
+ */
+static 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;
+}
+
+/*
+ * helper function to unlock both pages and extents in the tree.
+ */
+static 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;
+}
+#endif
+
+/*
+ * set the private field for a given byte offset in the tree. If there isn't
+ * an extent_state there already, this does nothing.
+ */
+int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
+{
+ struct rb_node *node;
+ struct extent_state *state;
+ int ret = 0;
+
+ spin_lock(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, start);
+ if (!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:
+ spin_unlock(&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;
+
+ spin_lock(&tree->lock);
+ /*
+ * this search will find all the extents that end after
+ * our range starts.
+ */
+ node = tree_search(tree, start);
+ if (!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:
+ spin_unlock(&tree->lock);
+ return ret;
+}
+
+/*
+ * searches a range in the state tree for a given mask.
+ * If 'filled' == 1, this returns 1 only if every 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;
+
+ spin_lock(&tree->lock);
+ node = tree_search(tree, 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;
+ }
+ }
+ spin_unlock(&tree->lock);
+ return bitset;
+}
+
+/*
+ * 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.
+ */
+static void end_bio_extent_writepage(struct bio *bio, int err)
+{
+ int uptodate = err == 0;
+ struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct extent_io_tree *tree;
+ u64 start;
+ u64 end;
+ int whole_page;
+ int ret;
+
+ do {
+ struct page *page = bvec->bv_page;
+ tree = &BTRFS_I(page->mapping->host)->io_tree;
+
+ 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 (tree->ops && tree->ops->writepage_end_io_hook) {
+ ret = tree->ops->writepage_end_io_hook(page, start,
+ end, NULL, uptodate);
+ if (ret)
+ uptodate = 0;
+ }
+
+ if (!uptodate && tree->ops &&
+ tree->ops->writepage_io_failed_hook) {
+ ret = tree->ops->writepage_io_failed_hook(bio, page,
+ start, end, NULL);
+ if (ret == 0) {
+ uptodate = (err == 0);
+ continue;
+ }
+ }
+
+ 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);
+ } while (bvec >= bio->bi_io_vec);
+
+ bio_put(bio);
+}
+
+/*
+ * 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.
+ */
+static void end_bio_extent_readpage(struct bio *bio, int err)
+{
+ 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;
+ u64 start;
+ u64 end;
+ int whole_page;
+ int ret;
+
+ if (err)
+ uptodate = 0;
+
+ do {
+ struct page *page = bvec->bv_page;
+ tree = &BTRFS_I(page->mapping->host)->io_tree;
+
+ 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,
+ NULL);
+ if (ret)
+ uptodate = 0;
+ }
+ if (!uptodate && tree->ops &&
+ tree->ops->readpage_io_failed_hook) {
+ ret = tree->ops->readpage_io_failed_hook(bio, page,
+ start, end, NULL);
+ if (ret == 0) {
+ uptodate =
+ test_bit(BIO_UPTODATE, &bio->bi_flags);
+ if (err)
+ uptodate = 0;
+ continue;
+ }
+ }
+
+ if (uptodate) {
+ set_extent_uptodate(tree, start, end,
+ GFP_ATOMIC);
+ }
+ unlock_extent(tree, start, end, GFP_ATOMIC);
+
+ if (whole_page) {
+ if (uptodate) {
+ SetPageUptodate(page);
+ } else {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+ unlock_page(page);
+ } else {
+ if (uptodate) {
+ check_page_uptodate(tree, page);
+ } else {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+ check_page_locked(tree, page);
+ }
+ } while (bvec >= bio->bi_io_vec);
+
+ bio_put(bio);
+}
+
+/*
+ * 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.
+ */
+static void end_bio_extent_preparewrite(struct bio *bio, int err)
+{
+ 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;
+ u64 start;
+ u64 end;
+
+ do {
+ struct page *page = bvec->bv_page;
+ tree = &BTRFS_I(page->mapping->host)->io_tree;
+
+ 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);
+}
+
+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_size = 0;
+ bio->bi_bdev = bdev;
+ bio->bi_sector = first_sector;
+ }
+ return bio;
+}
+
+static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
+ unsigned long bio_flags)
+{
+ int ret = 0;
+ struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct page *page = bvec->bv_page;
+ struct extent_io_tree *tree = bio->bi_private;
+ u64 start;
+ u64 end;
+
+ start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
+ end = start + bvec->bv_len - 1;
+
+ bio->bi_private = NULL;
+
+ bio_get(bio);
+
+ if (tree->ops && tree->ops->submit_bio_hook)
+ tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
+ mirror_num, bio_flags);
+ else
+ 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 mirror_num,
+ unsigned long prev_bio_flags,
+ unsigned long bio_flags)
+{
+ int ret = 0;
+ struct bio *bio;
+ int nr;
+ int contig = 0;
+ int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
+ int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
+ size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
+
+ if (bio_ret && *bio_ret) {
+ bio = *bio_ret;
+ if (old_compressed)
+ contig = bio->bi_sector == sector;
+ else
+ contig = bio->bi_sector + (bio->bi_size >> 9) ==
+ sector;
+
+ if (prev_bio_flags != bio_flags || !contig ||
+ (tree->ops && tree->ops->merge_bio_hook &&
+ tree->ops->merge_bio_hook(page, offset, page_size, bio,
+ bio_flags)) ||
+ bio_add_page(bio, page, page_size, offset) < page_size) {
+ ret = submit_one_bio(rw, bio, mirror_num,
+ prev_bio_flags);
+ bio = NULL;
+ } else {
+ return 0;
+ }
+ }
+ if (this_compressed)
+ nr = BIO_MAX_PAGES;
+ else
+ nr = bio_get_nr_vecs(bdev);
+
+ bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
+
+ bio_add_page(bio, page, 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, mirror_num, bio_flags);
+
+ return ret;
+}
+
+void set_page_extent_mapped(struct page *page)
+{
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ page_cache_get(page);
+ set_page_private(page, EXTENT_PAGE_PRIVATE);
+ }
+}
+
+static 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, int mirror_num,
+ unsigned long *bio_flags)
+{
+ 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 disk_io_size;
+ size_t blocksize = inode->i_sb->s_blocksize;
+ unsigned long this_bio_flag = 0;
+
+ set_page_extent_mapped(page);
+
+ end = page_end;
+ lock_extent(tree, start, end, GFP_NOFS);
+
+ if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
+ char *userpage;
+ size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
+
+ if (zero_offset) {
+ iosize = PAGE_CACHE_SIZE - zero_offset;
+ userpage = kmap_atomic(page, KM_USER0);
+ memset(userpage + zero_offset, 0, iosize);
+ flush_dcache_page(page);
+ kunmap_atomic(userpage, KM_USER0);
+ }
+ }
+ 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);
+
+ if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
+ this_bio_flag = EXTENT_BIO_COMPRESSED;
+
+ 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);
+ if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
+ disk_io_size = em->block_len;
+ sector = em->block_start >> 9;
+ } else {
+ sector = (em->block_start + extent_offset) >> 9;
+ disk_io_size = iosize;
+ }
+ bdev = em->bdev;
+ block_start = em->block_start;
+ if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
+ block_start = EXTENT_MAP_HOLE;
+ 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)) {
+ check_page_uptodate(tree, page);
+ unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
+ cur = cur + iosize;
+ page_offset += iosize;
+ continue;
+ }
+ /* we have an inline extent but it didn't get marked up
+ * to date. Error out
+ */
+ if (block_start == EXTENT_MAP_INLINE) {
+ SetPageError(page);
+ 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 pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
+ pnr -= page->index;
+ ret = submit_extent_page(READ, tree, page,
+ sector, disk_io_size, page_offset,
+ bdev, bio, pnr,
+ end_bio_extent_readpage, mirror_num,
+ *bio_flags,
+ this_bio_flag);
+ nr++;
+ *bio_flags = this_bio_flag;
+ }
+ if (ret)
+ SetPageError(page);
+ cur = cur + iosize;
+ page_offset += iosize;
+ }
+ 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;
+ unsigned long bio_flags = 0;
+ int ret;
+
+ ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
+ &bio_flags);
+ if (bio)
+ submit_one_bio(READ, bio, 0, bio_flags);
+ return ret;
+}
+
+/*
+ * 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;
+ u64 unlock_start;
+ sector_t sector;
+ struct extent_map *em;
+ struct block_device *bdev;
+ int ret;
+ int nr = 0;
+ size_t pg_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;
+ int page_started;
+ int compressed;
+ unsigned long nr_written = 0;
+
+ WARN_ON(!PageLocked(page));
+ pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
+ if (page->index > end_index ||
+ (page->index == end_index && !pg_offset)) {
+ page->mapping->a_ops->invalidatepage(page, 0);
+ unlock_page(page);
+ return 0;
+ }
+
+ if (page->index == end_index) {
+ char *userpage;
+
+ userpage = kmap_atomic(page, KM_USER0);
+ memset(userpage + pg_offset, 0,
+ PAGE_CACHE_SIZE - pg_offset);
+ kunmap_atomic(userpage, KM_USER0);
+ flush_dcache_page(page);
+ }
+ pg_offset = 0;
+
+ set_page_extent_mapped(page);
+
+ delalloc_start = start;
+ delalloc_end = 0;
+ page_started = 0;
+ if (!epd->extent_locked) {
+ while (delalloc_end < page_end) {
+ nr_delalloc = find_lock_delalloc_range(inode, tree,
+ page,
+ &delalloc_start,
+ &delalloc_end,
+ 128 * 1024 * 1024);
+ if (nr_delalloc == 0) {
+ delalloc_start = delalloc_end + 1;
+ continue;
+ }
+ tree->ops->fill_delalloc(inode, page, delalloc_start,
+ delalloc_end, &page_started,
+ &nr_written);
+ delalloc_start = delalloc_end + 1;
+ }
+
+ /* did the fill delalloc function already unlock and start
+ * the IO?
+ */
+ if (page_started) {
+ ret = 0;
+ goto update_nr_written;
+ }
+ }
+ lock_extent(tree, start, page_end, GFP_NOFS);
+
+ unlock_start = start;
+
+ if (tree->ops && tree->ops->writepage_start_hook) {
+ ret = tree->ops->writepage_start_hook(page, start,
+ page_end);
+ if (ret == -EAGAIN) {
+ unlock_extent(tree, start, page_end, GFP_NOFS);
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+ ret = 0;
+ goto update_nr_written;
+ }
+ }
+
+ nr_written++;
+
+ end = page_end;
+ if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0))
+ printk(KERN_ERR "btrfs delalloc bits after lock_extent\n");
+
+ if (last_byte <= start) {
+ clear_extent_dirty(tree, start, page_end, GFP_NOFS);
+ unlock_extent(tree, start, page_end, GFP_NOFS);
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, start,
+ page_end, NULL, 1);
+ unlock_start = page_end + 1;
+ 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);
+ unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, cur,
+ page_end, NULL, 1);
+ unlock_start = page_end + 1;
+ break;
+ }
+ em = epd->get_extent(inode, page, pg_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;
+ compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+ free_extent_map(em);
+ em = NULL;
+
+ /*
+ * compressed and inline extents are written through other
+ * paths in the FS
+ */
+ if (compressed || block_start == EXTENT_MAP_HOLE ||
+ block_start == EXTENT_MAP_INLINE) {
+ clear_extent_dirty(tree, cur,
+ cur + iosize - 1, GFP_NOFS);
+
+ unlock_extent(tree, unlock_start, cur + iosize - 1,
+ GFP_NOFS);
+
+ /*
+ * end_io notification does not happen here for
+ * compressed extents
+ */
+ if (!compressed && tree->ops &&
+ tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, cur,
+ cur + iosize - 1,
+ NULL, 1);
+ else if (compressed) {
+ /* we don't want to end_page_writeback on
+ * a compressed extent. this happens
+ * elsewhere
+ */
+ nr++;
+ }
+
+ cur += iosize;
+ pg_offset += iosize;
+ unlock_start = cur;
+ 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;
+ pg_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(KERN_ERR "btrfs 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, pg_offset, bdev,
+ &epd->bio, max_nr,
+ end_bio_extent_writepage,
+ 0, 0, 0);
+ if (ret)
+ SetPageError(page);
+ }
+ cur = cur + iosize;
+ pg_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);
+ }
+ if (unlock_start <= page_end)
+ unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
+ unlock_page(page);
+
+update_nr_written:
+ wbc->nr_to_write -= nr_written;
+ if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
+ wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
+ page->mapping->writeback_index = page->index + nr_written;
+ return 0;
+}
+
+/**
+ * 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 extent_write_cache_pages(struct extent_io_tree *tree,
+ struct address_space *mapping,
+ struct writeback_control *wbc,
+ writepage_t writepage, void *data,
+ void (*flush_fn)(void *))
+{
+ 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
+ */
+ if (tree->ops && tree->ops->write_cache_pages_lock_hook)
+ tree->ops->write_cache_pages_lock_hook(page);
+ else
+ 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) {
+ if (PageWriteback(page))
+ flush_fn(data);
+ 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;
+ }
+ return ret;
+}
+
+static noinline void flush_write_bio(void *data)
+{
+ struct extent_page_data *epd = data;
+ if (epd->bio) {
+ submit_one_bio(WRITE, epd->bio, 0, 0);
+ epd->bio = NULL;
+ }
+}
+
+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,
+ .extent_locked = 0,
+ };
+ 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);
+
+ extent_write_cache_pages(tree, mapping, &wbc_writepages,
+ __extent_writepage, &epd, flush_write_bio);
+ if (epd.bio)
+ submit_one_bio(WRITE, epd.bio, 0, 0);
+ return ret;
+}
+
+int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
+ u64 start, u64 end, get_extent_t *get_extent,
+ int mode)
+{
+ int ret = 0;
+ struct address_space *mapping = inode->i_mapping;
+ struct page *page;
+ unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
+ PAGE_CACHE_SHIFT;
+
+ struct extent_page_data epd = {
+ .bio = NULL,
+ .tree = tree,
+ .get_extent = get_extent,
+ .extent_locked = 1,
+ };
+ struct writeback_control wbc_writepages = {
+ .bdi = inode->i_mapping->backing_dev_info,
+ .sync_mode = mode,
+ .older_than_this = NULL,
+ .nr_to_write = nr_pages * 2,
+ .range_start = start,
+ .range_end = end + 1,
+ };
+
+ while (start <= end) {
+ page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
+ if (clear_page_dirty_for_io(page))
+ ret = __extent_writepage(page, &wbc_writepages, &epd);
+ else {
+ if (tree->ops && tree->ops->writepage_end_io_hook)
+ tree->ops->writepage_end_io_hook(page, start,
+ start + PAGE_CACHE_SIZE - 1,
+ NULL, 1);
+ unlock_page(page);
+ }
+ page_cache_release(page);
+ start += PAGE_CACHE_SIZE;
+ }
+
+ if (epd.bio)
+ submit_one_bio(WRITE, epd.bio, 0, 0);
+ return ret;
+}
+
+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,
+ .extent_locked = 0,
+ };
+
+ ret = extent_write_cache_pages(tree, mapping, wbc,
+ __extent_writepage, &epd,
+ flush_write_bio);
+ if (epd.bio)
+ submit_one_bio(WRITE, epd.bio, 0, 0);
+ return ret;
+}
+
+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;
+ unsigned long bio_flags = 0;
+
+ 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_file(&pvec);
+ __extent_read_full_page(tree, page, get_extent,
+ &bio, 0, &bio_flags);
+ }
+ page_cache_release(page);
+ }
+ if (pagevec_count(&pvec))
+ __pagevec_lru_add_file(&pvec);
+ BUG_ON(!list_empty(pages));
+ if (bio)
+ submit_one_bio(READ, bio, 0, bio_flags);
+ return 0;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * 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;
+}
+
+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, 0,
+ 0, 0);
+ 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;
+}
+
+/*
+ * a helper for releasepage, this tests for areas of the page that
+ * are locked or under IO and drops the related state bits if it is safe
+ * to drop the page.
+ */
+int try_release_extent_state(struct extent_map_tree *map,
+ struct extent_io_tree *tree, struct page *page,
+ gfp_t mask)
+{
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+ int ret = 1;
+
+ if (test_range_bit(tree, start, end,
+ EXTENT_IOBITS | EXTENT_ORDERED, 0))
+ ret = 0;
+ else {
+ if ((mask & GFP_NOFS) == GFP_NOFS)
+ mask = GFP_NOFS;
+ clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
+ 1, 1, mask);
+ }
+ return ret;
+}
+
+/*
+ * 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,
+ gfp_t mask)
+{
+ struct extent_map *em;
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+
+ if ((mask & __GFP_WAIT) &&
+ page->mapping->host->i_size > 16 * 1024 * 1024) {
+ u64 len;
+ while (start <= end) {
+ len = end - start + 1;
+ spin_lock(&map->lock);
+ em = lookup_extent_mapping(map, start, len);
+ if (!em || IS_ERR(em)) {
+ spin_unlock(&map->lock);
+ break;
+ }
+ if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
+ em->start != start) {
+ spin_unlock(&map->lock);
+ free_extent_map(em);
+ break;
+ }
+ if (!test_range_bit(tree, em->start,
+ extent_map_end(em) - 1,
+ EXTENT_LOCKED | EXTENT_WRITEBACK |
+ EXTENT_ORDERED,
+ 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);
+ }
+ }
+ return try_release_extent_state(map, tree, page, mask);
+}
+
+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;
+ size_t blksize = (1 << inode->i_blkbits);
+ struct extent_map *em;
+
+ lock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
+ GFP_NOFS);
+ em = get_extent(inode, NULL, 0, start, blksize, 0);
+ unlock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
+ GFP_NOFS);
+ if (!em || IS_ERR(em))
+ return 0;
+
+ if (em->block_start > EXTENT_MAP_LAST_BYTE)
+ goto out;
+
+ sector = (em->block_start + start - em->start) >> inode->i_blkbits;
+out:
+ free_extent_map(em);
+ return sector;
+}
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