Btrfs: move the extent buffer radix tree into the fs_info

I need to create a fake tree to test qgroups and I don't want to have to setup a
fake btree_inode.  The fact is we only use the radix tree for the fs_info, so
everybody else who allocates an extent_io_tree is just wasting the space anyway.
This patch moves the radix tree and its lock into btrfs_fs_info so there is less
stuff I have to fake to do qgroup sanity tests.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>

4 files changed, 34 insertions, 39 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7158c97fdc5e..a924274a503e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1659,6 +1659,10 @@ struct btrfs_fs_info {
         spinlock_t reada_lock;
         struct radix_tree_root reada_tree;
 
+        /* Extent buffer radix tree */
+        spinlock_t buffer_lock;
+        struct radix_tree_root buffer_radix;
+
         /* next backup root to be overwritten */
         int backup_root_index;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4ecee0a009cb..4a1871cf797b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1089,21 +1089,13 @@ int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
                                             u64 bytenr, u32 blocksize)
 {
-        struct inode *btree_inode = root->fs_info->btree_inode;
-        struct extent_buffer *eb;
-        eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree, bytenr);
-        return eb;
+        return find_extent_buffer(root->fs_info, bytenr);
 }
 
 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
                                                  u64 bytenr, u32 blocksize)
 {
-        struct inode *btree_inode = root->fs_info->btree_inode;
-        struct extent_buffer *eb;
-
-        eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
-                                 bytenr, blocksize);
-        return eb;
+        return alloc_extent_buffer(root->fs_info, bytenr, blocksize);
 }
 
 
@@ -2145,6 +2137,7 @@ int open_ctree(struct super_block *sb,
         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
 
         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
+        INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
         INIT_LIST_HEAD(&fs_info->trans_list);
         INIT_LIST_HEAD(&fs_info->dead_roots);
         INIT_LIST_HEAD(&fs_info->delayed_iputs);
@@ -2158,6 +2151,7 @@ int open_ctree(struct super_block *sb,
         spin_lock_init(&fs_info->free_chunk_lock);
         spin_lock_init(&fs_info->tree_mod_seq_lock);
         spin_lock_init(&fs_info->super_lock);
+        spin_lock_init(&fs_info->buffer_lock);
         rwlock_init(&fs_info->tree_mod_log_lock);
         mutex_init(&fs_info->reloc_mutex);
         seqlock_init(&fs_info->profiles_lock);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 92a3ad4656a6..2fa23b57d8df 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -194,11 +194,9 @@ void extent_io_tree_init(struct extent_io_tree *tree,
                          struct address_space *mapping)
 {
         tree->state = RB_ROOT;
-        INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
         tree->ops = NULL;
         tree->dirty_bytes = 0;
         spin_lock_init(&tree->lock);
-        spin_lock_init(&tree->buffer_lock);
         tree->mapping = mapping;
 }
 
@@ -3489,6 +3487,7 @@ static int write_one_eb(struct extent_buffer *eb,
                         struct extent_page_data *epd)
 {
         struct block_device *bdev = fs_info->fs_devices->latest_bdev;
+        struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
         u64 offset = eb->start;
         unsigned long i, num_pages;
         unsigned long bio_flags = 0;
@@ -3506,7 +3505,7 @@ static int write_one_eb(struct extent_buffer *eb,
 
                 clear_page_dirty_for_io(p);
                 set_page_writeback(p);
-                ret = submit_extent_page(rw, eb->tree, p, offset >> 9,
+                ret = submit_extent_page(rw, tree, p, offset >> 9,
                                          PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
                                          -1, end_bio_extent_buffer_writepage,
                                          0, epd->bio_flags, bio_flags);
@@ -4370,10 +4369,9 @@ static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
         __free_extent_buffer(eb);
 }
 
-static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
-                                                   u64 start,
-                                                   unsigned long len,
-                                                   gfp_t mask)
+static struct extent_buffer *
+__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
+                      unsigned long len, gfp_t mask)
 {
         struct extent_buffer *eb = NULL;
 
@@ -4382,7 +4380,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
                 return NULL;
         eb->start = start;
         eb->len = len;
-        eb->tree = tree;
+        eb->fs_info = fs_info;
         eb->bflags = 0;
         rwlock_init(&eb->lock);
         atomic_set(&eb->write_locks, 0);
@@ -4514,13 +4512,14 @@ static void mark_extent_buffer_accessed(struct extent_buffer *eb)
         }
 }
 
-struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
-                                                        u64 start)
+struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
+                                         u64 start)
 {
         struct extent_buffer *eb;
 
         rcu_read_lock();
-        eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
+        eb = radix_tree_lookup(&fs_info->buffer_radix,
+                               start >> PAGE_CACHE_SHIFT);
         if (eb && atomic_inc_not_zero(&eb->refs)) {
                 rcu_read_unlock();
                 mark_extent_buffer_accessed(eb);
@@ -4531,7 +4530,7 @@ struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
         return NULL;
 }
 
-struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
+struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
                                           u64 start, unsigned long len)
 {
         unsigned long num_pages = num_extent_pages(start, len);
@@ -4540,16 +4539,15 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
         struct extent_buffer *eb;
         struct extent_buffer *exists = NULL;
         struct page *p;
-        struct address_space *mapping = tree->mapping;
+        struct address_space *mapping = fs_info->btree_inode->i_mapping;
         int uptodate = 1;
         int ret;
 
-
-        eb = find_extent_buffer(tree, start);
+        eb = find_extent_buffer(fs_info, start);
         if (eb)
                 return eb;
 
-        eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
+        eb = __alloc_extent_buffer(fs_info, start, len, GFP_NOFS);
         if (!eb)
                 return NULL;
 
@@ -4604,12 +4602,13 @@ again:
         if (ret)
                 goto free_eb;
 
-        spin_lock(&tree->buffer_lock);
-        ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
-        spin_unlock(&tree->buffer_lock);
+        spin_lock(&fs_info->buffer_lock);
+        ret = radix_tree_insert(&fs_info->buffer_radix,
+                                start >> PAGE_CACHE_SHIFT, eb);
+        spin_unlock(&fs_info->buffer_lock);
         radix_tree_preload_end();
         if (ret == -EEXIST) {
-                exists = find_extent_buffer(tree, start);
+                exists = find_extent_buffer(fs_info, start);
                 if (exists)
                         goto free_eb;
                 else
@@ -4662,14 +4661,14 @@ static int release_extent_buffer(struct extent_buffer *eb)
         WARN_ON(atomic_read(&eb->refs) == 0);
         if (atomic_dec_and_test(&eb->refs)) {
                 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
-                        struct extent_io_tree *tree = eb->tree;
+                        struct btrfs_fs_info *fs_info = eb->fs_info;
 
                         spin_unlock(&eb->refs_lock);
 
-                        spin_lock(&tree->buffer_lock);
-                        radix_tree_delete(&tree->buffer,
+                        spin_lock(&fs_info->buffer_lock);
+                        radix_tree_delete(&fs_info->buffer_radix,
                                           eb->start >> PAGE_CACHE_SHIFT);
-                        spin_unlock(&tree->buffer_lock);
+                        spin_unlock(&fs_info->buffer_lock);
                 } else {
                         spin_unlock(&eb->refs_lock);
                 }
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 92e4347315e6..58b27e5ab521 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -95,12 +95,10 @@ struct extent_io_ops {
 
 struct extent_io_tree {
         struct rb_root state;
-        struct radix_tree_root buffer;
         struct address_space *mapping;
         u64 dirty_bytes;
         int track_uptodate;
         spinlock_t lock;
-        spinlock_t buffer_lock;
         struct extent_io_ops *ops;
 };
 
@@ -131,7 +129,7 @@ struct extent_buffer {
         unsigned long map_start;
         unsigned long map_len;
         unsigned long bflags;
-        struct extent_io_tree *tree;
+        struct btrfs_fs_info *fs_info;
         spinlock_t refs_lock;
         atomic_t refs;
         atomic_t io_pages;
@@ -267,11 +265,11 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private);
 void set_page_extent_mapped(struct page *page);
 
-struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
+struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
                                           u64 start, unsigned long len);
 struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len);
 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src);
-struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
+struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
                                          u64 start);
 void free_extent_buffer(struct extent_buffer *eb);
 void free_extent_buffer_stale(struct extent_buffer *eb);