8 files changed, 47 insertions, 21 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e801f226d7e0..4106264fbc65 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -220,10 +220,12 @@ struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
  */
 static void add_root_to_dirty_list(struct btrfs_root *root)
 {
+        spin_lock(&root->fs_info->trans_lock);
         if (root->track_dirty && list_empty(&root->dirty_list)) {
                 list_add(&root->dirty_list,
                          &root->fs_info->dirty_cowonly_roots);
         }
+        spin_unlock(&root->fs_info->trans_lock);
 }
 
 /*
@@ -723,7 +725,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 
                 cur = btrfs_find_tree_block(root, blocknr, blocksize);
                 if (cur)
-                        uptodate = btrfs_buffer_uptodate(cur, gen);
+                        uptodate = btrfs_buffer_uptodate(cur, gen, 0);
                 else
                         uptodate = 0;
                 if (!cur || !uptodate) {
@@ -1358,7 +1360,12 @@ static noinline int reada_for_balance(struct btrfs_root *root,
                 block1 = btrfs_node_blockptr(parent, slot - 1);
                 gen = btrfs_node_ptr_generation(parent, slot - 1);
                 eb = btrfs_find_tree_block(root, block1, blocksize);
-                if (eb && btrfs_buffer_uptodate(eb, gen))
+                /*
+                 * if we get -eagain from btrfs_buffer_uptodate, we
+                 * don't want to return eagain here.  That will loop
+                 * forever
+                 */
+                if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
                         block1 = 0;
                 free_extent_buffer(eb);
         }
@@ -1366,7 +1373,7 @@ static noinline int reada_for_balance(struct btrfs_root *root,
                 block2 = btrfs_node_blockptr(parent, slot + 1);
                 gen = btrfs_node_ptr_generation(parent, slot + 1);
                 eb = btrfs_find_tree_block(root, block2, blocksize);
-                if (eb && btrfs_buffer_uptodate(eb, gen))
+                if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
                         block2 = 0;
                 free_extent_buffer(eb);
         }
@@ -1504,8 +1511,9 @@ read_block_for_search(struct btrfs_trans_handle *trans,
 
         tmp = btrfs_find_tree_block(root, blocknr, blocksize);
         if (tmp) {
-                if (btrfs_buffer_uptodate(tmp, 0)) {
-                        if (btrfs_buffer_uptodate(tmp, gen)) {
+                /* first we do an atomic uptodate check */
+                if (btrfs_buffer_uptodate(tmp, 0, 1) > 0) {
+                        if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
                                 /*
                                  * we found an up to date block without
                                  * sleeping, return
@@ -1523,8 +1531,9 @@ read_block_for_search(struct btrfs_trans_handle *trans,
                         free_extent_buffer(tmp);
                         btrfs_set_path_blocking(p);
 
+                        /* now we're allowed to do a blocking uptodate check */
                         tmp = read_tree_block(root, blocknr, blocksize, gen);
-                        if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
+                        if (tmp && btrfs_buffer_uptodate(tmp, gen, 0) > 0) {
                                 *eb_ret = tmp;
                                 return 0;
                         }
@@ -1559,7 +1568,7 @@ read_block_for_search(struct btrfs_trans_handle *trans,
                  * and give up so that our caller doesn't loop forever
                  * on our EAGAINs.
                  */
-                if (!btrfs_buffer_uptodate(tmp, 0))
+                if (!btrfs_buffer_uptodate(tmp, 0, 0))
                         ret = -EIO;
                 free_extent_buffer(tmp);
         }
@@ -4043,7 +4052,7 @@ again:
                         tmp = btrfs_find_tree_block(root, blockptr,
                                             btrfs_level_size(root, level - 1));
 
-                        if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
+                        if (tmp && btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
                                 free_extent_buffer(tmp);
                                 break;
                         }
@@ -4166,7 +4175,8 @@ next:
                                 struct extent_buffer *cur;
                                 cur = btrfs_find_tree_block(root, blockptr,
                                             btrfs_level_size(root, level - 1));
-                                if (!cur || !btrfs_buffer_uptodate(cur, gen)) {
+                                if (!cur ||
+                                    btrfs_buffer_uptodate(cur, gen, 1) <= 0) {
                                         slot++;
                                         if (cur)
                                                 free_extent_buffer(cur);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d0c969beaad4..a7ffc88a7dbe 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -323,7 +323,8 @@ static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
  * in the wrong place.
  */
 static int verify_parent_transid(struct extent_io_tree *io_tree,
-                                 struct extent_buffer *eb, u64 parent_transid)
+                                 struct extent_buffer *eb, u64 parent_transid,
+                                 int atomic)
 {
         struct extent_state *cached_state = NULL;
         int ret;
@@ -331,6 +332,9 @@ static int verify_parent_transid(struct extent_io_tree *io_tree,
         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
                 return 0;
 
+        if (atomic)
+                return -EAGAIN;
+
         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
                          0, &cached_state);
         if (extent_buffer_uptodate(eb) &&
@@ -372,7 +376,8 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
                 ret = read_extent_buffer_pages(io_tree, eb, start,
                                                WAIT_COMPLETE,
                                                btree_get_extent, mirror_num);
-                if (!ret && !verify_parent_transid(io_tree, eb, parent_transid))
+                if (!ret && !verify_parent_transid(io_tree, eb,
+                                                   parent_transid, 0))
                         break;
 
                 /*
@@ -1202,7 +1207,7 @@ static int __must_check find_and_setup_root(struct btrfs_root *tree_root,
         root->commit_root = NULL;
         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
                                      blocksize, generation);
-        if (!root->node || !btrfs_buffer_uptodate(root->node, generation)) {
+        if (!root->node || !btrfs_buffer_uptodate(root->node, generation, 0)) {
                 free_extent_buffer(root->node);
                 root->node = NULL;
                 return -EIO;
@@ -3143,7 +3148,8 @@ int close_ctree(struct btrfs_root *root)
         return 0;
 }
 
-int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
+int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
+                          int atomic)
 {
         int ret;
         struct inode *btree_inode = buf->pages[0]->mapping->host;
@@ -3153,7 +3159,9 @@ int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
                 return ret;