Btrfs: extent_io and extent_state optimizations

The end_bio routines are changed to take a pointer to the extent state
struct, and the state tree is walked in order to set/clear appropriate
bits as IO completes.  This greatly reduces the number of rbtree searches
done by the end_bio handlers, and reduces lock contention.

The extent_io releasepage function is changed to avoid expensive searches
for locked state.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

4 files changed, 298 insertions, 114 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4c4ebea0b2a9..e29a0716f6a9 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -274,7 +274,7 @@ int btree_readpage(struct file *file, struct page *page)
         return extent_read_full_page(tree, page, btree_get_extent);
 }
 
-static int btree_releasepage(struct page *page, gfp_t unused_gfp_flags)
+static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 {
         struct extent_io_tree *tree;
         struct extent_map_tree *map;
@@ -282,7 +282,7 @@ static int btree_releasepage(struct page *page, gfp_t unused_gfp_flags)
 
         tree = &BTRFS_I(page->mapping->host)->io_tree;
         map = &BTRFS_I(page->mapping->host)->extent_tree;
-        ret = try_release_extent_mapping(map, tree, page);
+        ret = try_release_extent_mapping(map, tree, page, gfp_flags);
         if (ret == 1) {
                 ClearPagePrivate(page);
                 set_page_private(page, 0);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 15cc158a0498..1f734c34dc24 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -27,13 +27,11 @@ 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;
 };
 
@@ -69,7 +67,7 @@ void extent_io_exit(void)
 
         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));
+                printk("state leak: start %Lu end %Lu state %lu in tree %p refs %d\n", state->start, state->end, state->state, state->tree, atomic_read(&state->refs));
                 list_del(&state->list);
                 kmem_cache_free(extent_state_cache, state);
 
@@ -87,7 +85,7 @@ void extent_io_tree_init(struct extent_io_tree *tree,
         tree->state.rb_node = NULL;
         tree->ops = NULL;
         tree->dirty_bytes = 0;
-        rwlock_init(&tree->lock);
+        spin_lock_init(&tree->lock);
         spin_lock_init(&tree->lru_lock);
         tree->mapping = mapping;
         INIT_LIST_HEAD(&tree->buffer_lru);
@@ -110,18 +108,13 @@ 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);
+        state->tree = NULL;
 
         atomic_set(&state->refs, 1);
         init_waitqueue_head(&state->wq);
@@ -131,14 +124,10 @@ 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);
+                WARN_ON(state->tree);
                 kmem_cache_free(extent_state_cache, state);
         }
 }
@@ -164,7 +153,6 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
         }
 
         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;
@@ -216,8 +204,9 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
 
 static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
 {
-        struct rb_node *prev;
+        struct rb_node *prev = NULL;
         struct rb_node *ret;
+
         ret = __tree_search(root, offset, &prev, NULL);
         if (!ret)
                 return prev;
@@ -248,7 +237,7 @@ static int merge_state(struct extent_io_tree *tree,
                 if (other->end == state->start - 1 &&
                     other->state == state->state) {
                         state->start = other->start;
-                        other->in_tree = 0;
+                        other->tree = NULL;
                         rb_erase(&other->rb_node, &tree->state);
                         free_extent_state(other);
                 }
@@ -259,7 +248,7 @@ static int merge_state(struct extent_io_tree *tree,
                 if (other->start == state->end + 1 &&
                     other->state == state->state) {
                         other->start = state->start;
-                        state->in_tree = 0;
+                        state->tree = NULL;
                         rb_erase(&state->rb_node, &tree->state);
                         free_extent_state(state);
                 }
@@ -300,6 +289,7 @@ static int insert_state(struct extent_io_tree *tree,
                 free_extent_state(state);
                 return -EEXIST;
         }
+        state->tree = tree;
         merge_state(tree, state);
         return 0;
 }
@@ -335,6 +325,7 @@ static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
                 free_extent_state(prealloc);
                 return -EEXIST;
         }
+        prealloc->tree = tree;
         return 0;
 }
 
@@ -361,9 +352,9 @@ static int clear_state_bit(struct extent_io_tree *tree,
         if (wake)
                 wake_up(&state->wq);
         if (delete || state->state == 0) {
-                if (state->in_tree) {
+                if (state->tree) {
                         rb_erase(&state->rb_node, &tree->state);
-                        state->in_tree = 0;
+                        state->tree = NULL;
                         free_extent_state(state);
                 } else {
                         WARN_ON(1);
@@ -404,7 +395,7 @@ again:
                         return -ENOMEM;
         }
 
-        write_lock_irqsave(&tree->lock, flags);
+        spin_lock_irqsave(&tree->lock, flags);
         /*
          * this search will find the extents that end after
          * our range starts
@@ -434,6 +425,8 @@ again:
          */
 
         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;
@@ -455,6 +448,8 @@ again:
          * 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);
 
@@ -471,7 +466,7 @@ again:
         goto search_again;
 
 out:
-        write_unlock_irqrestore(&tree->lock, flags);
+        spin_unlock_irqrestore(&tree->lock, flags);
         if (prealloc)
                 free_extent_state(prealloc);
 
@@ -480,7 +475,7 @@ out:
 search_again:
         if (start > end)
                 goto out;
-        write_unlock_irqrestore(&tree->lock, flags);
+        spin_unlock_irqrestore(&tree->lock, flags);
         if (mask & __GFP_WAIT)
                 cond_resched();
         goto again;
@@ -492,9 +487,9 @@ static int wait_on_state(struct extent_io_tree *tree,
 {
         DEFINE_WAIT(wait);
         prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
-        read_unlock_irq(&tree->lock);
+        spin_unlock_irq(&tree->lock);
         schedule();
-        read_lock_irq(&tree->lock);
+        spin_lock_irq(&tree->lock);
         finish_wait(&state->wq, &wait);
         return 0;
 }
@@ -509,7 +504,7 @@ 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);
+        spin_lock_irq(&tree->lock);
 again:
         while (1) {
                 /*
@@ -538,13 +533,13 @@ again:
                         break;
 
                 if (need_resched()) {
-                        read_unlock_irq(&tree->lock);
+                        spin_unlock_irq(&tree->lock);
                         cond_resched();
-                        read_lock_irq(&tree->lock);
+                        spin_lock_irq(&tree->lock);
                 }
         }
 out:
-        read_unlock_irq(&tree->lock);
+        spin_unlock_irq(&tree->lock);
         return 0;
 }
 EXPORT_SYMBOL(wait_extent_bit);
@@ -589,7 +584,7 @@ again:
                         return -ENOMEM;
         }
 
-        write_lock_irqsave(&tree->lock, flags);
+        spin_lock_irqsave(&tree->lock, flags);
         /*
          * this search will find all the extents that end after
          * our range starts.
@@ -709,7 +704,7 @@ again:
         goto search_again;
 
 out:
-        write_unlock_irqrestore(&tree->lock, flags);
+        spin_unlock_irqrestore(&tree->lock, flags);
         if (prealloc)
                 free_extent_state(prealloc);
 
@@ -718,7 +713,7 @@ out:
 search_again:
         if (start > end)
                 goto out;
-        write_unlock_irqrestore(&tree->lock, flags);
+        spin_unlock_irqrestore(&tree->lock, flags);
         if (mask & __GFP_WAIT)
                 cond_resched();
         goto again;
@@ -817,10 +812,6 @@ int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
 }
 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;
@@ -896,7 +887,7 @@ int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
         struct extent_state *state;
         int ret = 1;
 
-        read_lock_irq(&tree->lock);
+        spin_lock_irq(&tree->lock);
         /*
          * this search will find all the extents that end after
          * our range starts.
@@ -919,7 +910,7 @@ int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
                         break;
         }
 out:
-        read_unlock_irq(&tree->lock);
+        spin_unlock_irq(&tree->lock);
         return ret;
 }
 EXPORT_SYMBOL(find_first_extent_bit);
@@ -933,7 +924,7 @@ u64 find_lock_delalloc_range(struct extent_io_tree *tree,
         u64 found = 0;
         u64 total_bytes = 0;
 
-        write_lock_irq(&tree->lock);
+        spin_lock_irq(&tree->lock);
         /*
          * this search will find all the extents that end after
          * our range starts.
@@ -976,9 +967,9 @@ search_again:
                         atomic_inc(&state->refs);
                         prepare_to_wait(&state->wq, &wait,
                                         TASK_UNINTERRUPTIBLE);
-                        write_unlock_irq(&tree->lock);
+                        spin_unlock_irq(&tree->lock);
                         schedule();
-                        write_lock_irq(&tree->lock);
+                        spin_lock_irq(&tree->lock);
                         finish_wait(&state->wq, &wait);
                         free_extent_state(state);
                         goto search_again;
@@ -997,7 +988,7 @@ search_again:
                         break;
         }
 out:
-        write_unlock_irq(&tree->lock);
+        spin_unlock_irq(&tree->lock);
         return found;
 }
 
@@ -1017,7 +1008,7 @@ u64 count_range_bits(struct extent_io_tree *tree,
                 return 0;
         }
 
-        write_lock_irq(&tree->lock);
+        spin_lock_irq(&tree->lock);
         if (cur_start == 0 && bits == EXTENT_DIRTY) {
                 total_bytes = tree->dirty_bytes;
                 goto out;
@@ -1050,7 +1041,7 @@ u64 count_range_bits(struct extent_io_tree *tree,
                         break;
         }
 out:
-        write_unlock_irq(&tree->lock);
+        spin_unlock_irq(&tree->lock);
         return total_bytes;
 }
 /*
@@ -1122,7 +1113,7 @@ int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
         struct extent_state *state;
         int ret = 0;
 
-        write_lock_irq(&tree->lock);
+        spin_lock_irq(&tree->lock);
         /*
          * this search will find all the extents that end after
          * our range starts.
@@ -1139,7 +1130,7 @@ int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
         }
         state->private = private;
 out:
-        write_unlock_irq(&tree->lock);
+        spin_unlock_irq(&tree->lock);
         return ret;
 }
 
@@ -1149,7 +1140,7 @@ int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
         struct extent_state *state;
         int ret = 0;
 
-        read_lock_irq(&tree->lock);
+        spin_lock_irq(&tree->lock);
         /*
          * this search will find all the extents that end after
          * our range starts.
@@ -1166,13 +1157,13 @@ int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
         }
         *private = state->private;
 out:
-        read_unlock_irq(&tree->lock);
+        spin_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
+ * 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.
  */
@@ -1184,7 +1175,7 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
         int bitset = 0;
         unsigned long flags;
 
-        read_lock_irqsave(&tree->lock, flags);
+        spin_lock_irqsave(&tree->lock, flags);
         node = tree_search(&tree->state, start);
         while (node && start <= end) {
                 state = rb_entry(node, struct extent_state, rb_node);
@@ -1215,7 +1206,7 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
                         break;
                 }
         }
-        read_unlock_irqrestore(&tree->lock, flags);
+        spin_unlock_irqrestore(&tree->lock, flags);
         return bitset;
 }
 EXPORT_SYMBOL(test_range_bit);
@@ -1282,16 +1273,19 @@ static int end_bio_extent_writepage(struct bio *bio,
 {
         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;
+        struct extent_state *state = bio->bi_private;
+        struct extent_io_tree *tree = state->tree;
+        struct rb_node *node;
         u64 start;
         u64 end;
+        u64 cur;
         int whole_page;
+        unsigned long flags;
 
 #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) +
@@ -1311,16 +1305,80 @@ static int end_bio_extent_writepage(struct bio *bio,
                         ClearPageUptodate(page);
                         SetPageError(page);
                 }
-                clear_extent_writeback(tree, start, end, GFP_ATOMIC);
+
+                if (tree->ops && tree->ops->writepage_end_io_hook) {
+                        tree->ops->writepage_end_io_hook(page, start, end,
+                                                         state);
+                }
+
+                /*
+                 * bios can get merged in funny ways, and so we need to
+                 * be careful with the state variable.  We know the
+                 * state won't be merged with others because it has
+                 * WRITEBACK set, but we can't be sure each biovec is
+                 * sequential in the file.  So, if our cached state
+                 * doesn't match the expected end, search the tree
+                 * for the correct one.
+                 */
+
+                spin_lock_irqsave(&tree->lock, flags);
+                if (!state || state->end != end) {
+                        state = NULL;
+                        node = __tree_search(&tree->state, start, NULL, NULL);
+                        if (node) {
+                                state = rb_entry(node, struct extent_state,
+                                                 rb_node);
+                                if (state->end != end ||
+                                    !(state->state & EXTENT_WRITEBACK))
+                                        state = NULL;
+                        }
+                        if (!state) {
+                                spin_unlock_irqrestore(&tree->lock, flags);
+                                clear_extent_writeback(tree, start,
+                                                       end, GFP_ATOMIC);
+                                goto next_io;
+                        }
+                }
+                cur = end;
+                while(1) {
+                        struct extent_state *clear = state;
+                        cur = state->start;
+                        node = rb_prev(&state->rb_node);
+                        if (node) {
+                                state = rb_entry(node,
+                                                 struct extent_state,
+                                                 rb_node);
+                        } else {
+                                state = NULL;
+                        }
+
+                        clear_state_bit(tree, clear, EXTENT_WRITEBACK,
+                                        1, 0);
+                        if (cur == start)
+                                break;
+                        if (cur < start) {
+                                WARN_ON(1);
+                                break;
+                        }
+                        if (!node)
+                                break;
+                }
+                /* before releasing the lock, make sure the next state
+                 * variable has the expected bits set and corresponds
+                 * to the correct offsets in the file
+                 */
+                if (state && (state->end + 1 != start ||
+                    !state->state & EXTENT_WRITEBACK)) {
+                        state = NULL;
+                }
+                spin_unlock_irqrestore(&tree->lock, flags);
+next_io:
 
                 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;
@@ -1347,9 +1405,13 @@ static int end_bio_extent_readpage(struct bio *bio,
 {
         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;
+        struct extent_state *state = bio->bi_private;
+        struct extent_io_tree *tree = state->tree;
+        struct rb_node *node;
         u64 start;
         u64 end;
+        u64 cur;
+        unsigned long flags;
         int whole_page;
         int ret;
 
@@ -1373,27 +1435,83 @@ static int end_bio_extent_readpage(struct bio *bio,
                         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);
+                        ret = tree->ops->readpage_end_io_hook(page, start, end,
+                                                              state);
                         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);
+                spin_lock_irqsave(&tree->lock, flags);
+                if (!state || state->end != end) {
+                        state = NULL;
+                        node = __tree_search(&tree->state, start, NULL, NULL);
+                        if (node) {
+                                state = rb_entry(node, struct extent_state,
+                                                 rb_node);
+                                if (state->end != end ||
+                                    !(state->state & EXTENT_LOCKED))
+                                        state = NULL;
+                        }
+                        if (!state) {
+                                spin_unlock_irqrestore(&tree->lock, flags);
+                                set_extent_uptodate(tree, start, end,
+                                                    GFP_ATOMIC);
+                                unlock_extent(tree, start, end, GFP_ATOMIC);
+                                goto next_io;
+                        }
+                }
 
-                if (whole_page)
+                cur = end;
+                while(1) {
+                        struct extent_state *clear = state;
+                        cur = state->start;
+                        node = rb_prev(&state->rb_node);
+                        if (node) {
+                                state = rb_entry(node,
+                                         struct extent_state,
+                                         rb_node);
+                        } else {
+                                state = NULL;
+                        }
+                        clear->state |= EXTENT_UPTODATE;
+                        clear_state_bit(tree, clear, EXTENT_LOCKED,
+                                        1, 0);
+                        if (cur == start)
+                                break;
+                        if (cur < start) {
+                                WARN_ON(1);
+                                break;
+                        }
+                        if (!node)
+                                break;
+                }
+                /* before releasing the lock, make sure the next state
+                 * variable has the expected bits set and corresponds
+                 * to the correct offsets in the file
+                 */
+                if (state && (state->end + 1 != start ||
+                    !state->state & EXTENT_WRITEBACK)) {
+                        state = NULL;
+                }
+                spin_unlock_irqrestore(&tree->lock, flags);
+next_io:
+                if (whole_page) {
+                        if (uptodate) {
+                                SetPageUptodate(page);
+                        } else {
+                                ClearPageUptodate(page);
+                                SetPageError(page);
+                        }
                         unlock_page(page);
-                else
+                } 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);
@@ -1416,7 +1534,8 @@ static int end_bio_extent_preparewrite(struct bio *bio,
 {
         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;
+        struct extent_state *state = bio->bi_private;
+        struct extent_io_tree *tree = state->tree;
         u64 start;
         u64 end;
 
@@ -1475,6 +1594,29 @@ static int submit_one_bio(int rw, struct bio *bio)
 {
         u64 maxsector;
         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;
+        struct rb_node *node;
+        struct extent_state *state;
+        u64 start;
+        u64 end;
+
+        start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
+        end = start + bvec->bv_len - 1;
+
+        spin_lock_irq(&tree->lock);
+        node = __tree_search(&tree->state, start, NULL, NULL);
+        BUG_ON(!node);
+        state = rb_entry(node, struct extent_state, rb_node);
+        while(state->end < end) {
+                node = rb_next(node);
+                state = rb_entry(node, struct extent_state, rb_node);
+        }
+        BUG_ON(state->end != end);
+        spin_unlock_irq(&tree->lock);
+
+        bio->bi_private = state;
 
         bio_get(bio);
 
@@ -1519,9 +1661,12 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
         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 {
@@ -1635,6 +1780,16 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
                         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) {
@@ -2205,7 +2360,8 @@ EXPORT_SYMBOL(extent_prepare_write);
  * map records are removed
  */
 int try_release_extent_mapping(struct extent_map_tree *map,
-                               struct extent_io_tree *tree, struct page *page)
+                               struct extent_io_tree *tree, struct page *page,
+                               gfp_t mask)
 {
         struct extent_map *em;
         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
@@ -2213,30 +2369,42 @@ int try_release_extent_mapping(struct extent_map_tree *map,
         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)) {
+        if ((mask & __GFP_WAIT) &&
+            page->mapping->host->i_size > 16 * 1024 * 1024) {
+                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 (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, 0)) {
+                                remove_extent_mapping(map, em);
+                                /* once for the rb tree */
+                                free_extent_map(em);
+                        }
+                        start = extent_map_end(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 */
+
+                        /* once for us */
                         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))
+        if (test_range_bit(tree, orig_start, end, EXTENT_IOBITS, 0))
                 ret = 0;
-        else
+        else {
+                if ((mask & GFP_NOFS) == GFP_NOFS)
+                        mask = GFP_NOFS;
                 clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,
-                                 1, 1, GFP_NOFS);
+                                 1, 1, mask);
+        }
         return ret;
 }
 EXPORT_SYMBOL(try_release_extent_mapping);
@@ -2553,13 +2721,13 @@ int clear_extent_buffer_dirty(struct extent_io_tree *tree,
                         }
                 }
                 clear_page_dirty_for_io(page);
-                write_lock_irq(&page->mapping->tree_lock);
+                read_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);
+                read_unlock_irq(&page->mapping->tree_lock);
                 unlock_page(page);
         }
         return 0;
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 06be1fe84b29..f1e8bf251f32 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -23,19 +23,23 @@
 #define EXTENT_PAGE_PRIVATE 1
 #define EXTENT_PAGE_PRIVATE_FIRST_PAGE 3
 
+struct extent_state;
+
 struct extent_io_ops {
         int (*fill_delalloc)(struct inode *inode, u64 start, u64 end);
         int (*writepage_io_hook)(struct page *page, u64 start, u64 end);
         int (*readpage_io_hook)(struct page *page, u64 start, u64 end);
-        int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end);
-        void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end);
+        int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end,
+                                    struct extent_state *state);
+        void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,
+                                      struct extent_state *state);
 };
 
 struct extent_io_tree {
         struct rb_root state;
         struct address_space *mapping;
         u64 dirty_bytes;
-        rwlock_t lock;
+        spinlock_t lock;
         struct extent_io_ops *ops;
         spinlock_t lru_lock;
         struct list_head buffer_lru;
@@ -45,8 +49,8 @@ struct extent_io_tree {
 struct extent_state {
         u64 start;
         u64 end; /* inclusive */
-        int in_tree;
         struct rb_node rb_node;
+        struct extent_io_tree *tree;
         wait_queue_head_t wq;
         atomic_t refs;
         unsigned long state;
@@ -82,7 +86,8 @@ void extent_io_tree_init(struct extent_io_tree *tree,
                           struct address_space *mapping, gfp_t mask);
 void extent_io_tree_empty_lru(struct extent_io_tree *tree);
 int try_release_extent_mapping(struct extent_map_tree *map,
-                               struct extent_io_tree *tree, struct page *page);
+                               struct extent_io_tree *tree, struct page *page,
+                               gfp_t mask);
 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);
 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);
 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 484551274100..bac8722e14e1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -331,7 +331,8 @@ out:
         return ret;
 }
 
-int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end)
+int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
+                               struct extent_state *state)
 {
         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
         struct inode *inode = page->mapping->host;
@@ -347,7 +348,12 @@ int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end)
             btrfs_test_flag(inode, NODATASUM))
                 return 0;
 
-        ret = get_state_private(io_tree, start, &private);
+        if (state->start == start) {
+                private = state->private;
+                ret = 0;
+        } else {
+                ret = get_state_private(io_tree, start, &private);
+        }
         local_irq_save(flags);
         kaddr = kmap_atomic(page, KM_IRQ0);
         if (ret) {
@@ -1830,7 +1836,7 @@ out_unlock:
 }
 
 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
-                                    size_t page_offset, u64 start, u64 len,
+                                    size_t pg_offset, u64 start, u64 len,
                                     int create)
 {
         int ret;
@@ -1865,7 +1871,10 @@ again:
                                start, len, em->start, em->len);
                         WARN_ON(1);
                 }
-                goto out;
+                if (em->block_start == EXTENT_MAP_INLINE && page)
+                        free_extent_map(em);
+                else
+                        goto out;
         }
         em = alloc_extent_map(GFP_NOFS);
         if (!em) {
@@ -1930,6 +1939,7 @@ again:
                 em->len = extent_end - extent_start;
                 goto insert;
         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+                u64 page_start;
                 unsigned long ptr;
                 char *map;
                 size_t size;
@@ -1959,16 +1969,17 @@ again:
                         goto out;
                 }
 
-                extent_offset = ((u64)page->index << PAGE_CACHE_SHIFT) -
-                        extent_start + page_offset;
-                copy_size = min_t(u64, PAGE_CACHE_SIZE - page_offset,
+                page_start = page_offset(page) + pg_offset;
+                extent_offset = page_start - extent_start;
+                copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
                                 size - extent_offset);
                 em->start = extent_start + extent_offset;
-                em->len = copy_size;
+                em->len = (copy_size + root->sectorsize - 1) &
+                        ~((u64)root->sectorsize - 1);
                 map = kmap(page);
                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
                 if (create == 0 && !PageUptodate(page)) {
-                        read_extent_buffer(leaf, map + page_offset, ptr,
+                        read_extent_buffer(leaf, map + pg_offset, ptr,
                                            copy_size);
                         flush_dcache_page(page);
                 } else if (create && PageUptodate(page)) {
@@ -1980,7 +1991,7 @@ again:
                                 trans = btrfs_start_transaction(root, 1);
                                 goto again;
                         }
-                        write_extent_buffer(leaf, map + page_offset, ptr,
+                        write_extent_buffer(leaf, map + pg_offset, ptr,
                                             copy_size);
                         btrfs_mark_buffer_dirty(leaf);
                 }
@@ -2077,7 +2088,7 @@ btrfs_readpages(struct file *file, struct address_space *mapping,
                                 btrfs_get_extent);
 }
 
-static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags)
+static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
 {
         struct extent_io_tree *tree;
         struct extent_map_tree *map;
@@ -2085,7 +2096,7 @@ static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags)
 
         tree = &BTRFS_I(page->mapping->host)->io_tree;
         map = &BTRFS_I(page->mapping->host)->extent_tree;
-        ret = try_release_extent_mapping(map, tree, page);
+        ret = try_release_extent_mapping(map, tree, page, gfp_flags);
         if (ret == 1) {
                 ClearPagePrivate(page);
                 set_page_private(page, 0);