Btrfs: mark delayed refs as for cow

Add a for_cow parameter to add_delayed_*_ref and pass the appropriate value
from every call site. The for_cow parameter will later on be used to
determine if a ref will change anything with respect to qgroups.

Delayed refs coming from relocation are always counted as for_cow, as they
don't change subvol quota.

Also pass in the fs_info for later use.

btrfs_find_all_roots() will use this as an optimization, as changes that are
for_cow will not change anything with respect to which root points to a
certain leaf. Thus, we don't need to add the current sequence number to
those delayed refs.

Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

1 files changed, 60 insertions, 41 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 813c6bb96c9a..dc8b9a834596 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1872,20 +1872,24 @@ static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root,
                          u64 bytenr, u64 num_bytes, u64 parent,
-                         u64 root_objectid, u64 owner, u64 offset)
+                         u64 root_objectid, u64 owner, u64 offset, int for_cow)
 {
         int ret;
+        struct btrfs_fs_info *fs_info = root->fs_info;
+
         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
                root_objectid == BTRFS_TREE_LOG_OBJECTID);
 
         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
-                ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
+                ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
+                                        num_bytes,
                                         parent, root_objectid, (int)owner,
-                                        BTRFS_ADD_DELAYED_REF, NULL);
+                                        BTRFS_ADD_DELAYED_REF, NULL, for_cow);
         } else {
-                ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
+                ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
+                                        num_bytes,
                                         parent, root_objectid, owner, offset,
-                                        BTRFS_ADD_DELAYED_REF, NULL);
+                                        BTRFS_ADD_DELAYED_REF, NULL, for_cow);
         }
         return ret;
 }
@@ -2405,7 +2409,8 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
         extent_op->update_key = 0;
         extent_op->is_data = is_data ? 1 : 0;
 
-        ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
+        ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
+                                          num_bytes, extent_op);
         if (ret)
                 kfree(extent_op);
         return ret;
@@ -2590,7 +2595,7 @@ out:
 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root,
                            struct extent_buffer *buf,
-                           int full_backref, int inc)
+                           int full_backref, int inc, int for_cow)
 {
         u64 bytenr;
         u64 num_bytes;
@@ -2603,7 +2608,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
         int level;
         int ret = 0;
         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
-                            u64, u64, u64, u64, u64, u64);
+                            u64, u64, u64, u64, u64, u64, int);
 
         ref_root = btrfs_header_owner(buf);
         nritems = btrfs_header_nritems(buf);
@@ -2640,14 +2645,15 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
                         key.offset -= btrfs_file_extent_offset(buf, fi);
                         ret = process_func(trans, root, bytenr, num_bytes,
                                            parent, ref_root, key.objectid,
-                                           key.offset);
+                                           key.offset, for_cow);
                         if (ret)
                                 goto fail;
                 } else {
                         bytenr = btrfs_node_blockptr(buf, i);
                         num_bytes = btrfs_level_size(root, level - 1);
                         ret = process_func(trans, root, bytenr, num_bytes,
-                                           parent, ref_root, level - 1, 0);
+                                           parent, ref_root, level - 1, 0,
+                                           for_cow);
                         if (ret)
                                 goto fail;
                 }
@@ -2659,15 +2665,15 @@ fail:
 }
 
 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-                  struct extent_buffer *buf, int full_backref)
+                  struct extent_buffer *buf, int full_backref, int for_cow)
 {
-        return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
+        return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
 }
 
 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-                  struct extent_buffer *buf, int full_backref)
+                  struct extent_buffer *buf, int full_backref, int for_cow)
 {
-        return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
+        return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
 }
 
 static int write_one_cache_group(struct btrfs_trans_handle *trans,
@@ -4937,16 +4943,17 @@ out:
 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root,
                            struct extent_buffer *buf,
-                           u64 parent, int last_ref)
+                           u64 parent, int last_ref, int for_cow)
 {
         struct btrfs_block_group_cache *cache = NULL;
         int ret;
 
         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
-                ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
-                                                parent, root->root_key.objectid,
-                                                btrfs_header_level(buf),
-                                                BTRFS_DROP_DELAYED_REF, NULL);
+                ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
+                                        buf->start, buf->len,
+                                        parent, root->root_key.objectid,
+                                        btrfs_header_level(buf),
+                                        BTRFS_DROP_DELAYED_REF, NULL, for_cow);
                 BUG_ON(ret);
         }
 
@@ -4981,12 +4988,12 @@ out:
         btrfs_put_block_group(cache);
 }
 
-int btrfs_free_extent(struct btrfs_trans_handle *trans,
-                      struct btrfs_root *root,
-                      u64 bytenr, u64 num_bytes, u64 parent,
-                      u64 root_objectid, u64 owner, u64 offset)
+int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+                      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
+                      u64 owner, u64 offset, int for_cow)
 {
         int ret;
+        struct btrfs_fs_info *fs_info = root->fs_info;
 
         /*
          * tree log blocks never actually go into the extent allocation
@@ -4998,14 +5005,17 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
                 ret = 0;
         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
-                ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
+                ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
+                                        num_bytes,
                                         parent, root_objectid, (int)owner,
-                                        BTRFS_DROP_DELAYED_REF, NULL);
+                                        BTRFS_DROP_DELAYED_REF, NULL, for_cow);
                 BUG_ON(ret);
         } else {
-                ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
-                                        parent, root_objectid, owner,
-                                        offset, BTRFS_DROP_DELAYED_REF, NULL);
+                ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
+                                                num_bytes,
+                                                parent, root_objectid, owner,
+                                                offset, BTRFS_DROP_DELAYED_REF,
+                                                NULL, for_cow);
                 BUG_ON(ret);
         }
         return ret;
@@ -5826,9 +5836,10 @@ int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 
         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
 
-        ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
-                                         0, root_objectid, owner, offset,
-                                         BTRFS_ADD_DELAYED_EXTENT, NULL);
+        ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
+                                         ins->offset, 0,
+                                         root_objectid, owner, offset,
+                                         BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
         return ret;
 }
 
@@ -5998,7 +6009,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
                                         struct btrfs_root *root, u32 blocksize,
                                         u64 parent, u64 root_objectid,
                                         struct btrfs_disk_key *key, int level,
-                                        u64 hint, u64 empty_size)
+                                        u64 hint, u64 empty_size, int for_cow)
 {
         struct btrfs_key ins;
         struct btrfs_block_rsv *block_rsv;
@@ -6042,10 +6053,11 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
                 extent_op->update_flags = 1;
                 extent_op->is_data = 0;
 
-                ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
+                ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
+                                        ins.objectid,
                                         ins.offset, parent, root_objectid,
                                         level, BTRFS_ADD_DELAYED_EXTENT,
-                                        extent_op);
+                                        extent_op, for_cow);
                 BUG_ON(ret);
         }
         return buf;
@@ -6062,6 +6074,7 @@ struct walk_control {
         int keep_locks;
         int reada_slot;
         int reada_count;
+        int for_reloc;
 };
 
 #define DROP_REFERENCE  1
@@ -6200,9 +6213,9 @@ static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
         /* wc->stage == UPDATE_BACKREF */
         if (!(wc->flags[level] & flag)) {
                 BUG_ON(!path->locks[level]);
-                ret = btrfs_inc_ref(trans, root, eb, 1);
+                ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
                 BUG_ON(ret);
-                ret = btrfs_dec_ref(trans, root, eb, 0);
+                ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
                 BUG_ON(ret);
                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
                                                   eb->len, flag, 0);
@@ -6346,7 +6359,7 @@ skip:
                 }
 
                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
-                                        root->root_key.objectid, level - 1, 0);
+                                root->root_key.objectid, level - 1, 0, 0);
                 BUG_ON(ret);
         }
         btrfs_tree_unlock(next);
@@ -6420,9 +6433,11 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
         if (wc->refs[level] == 1) {
                 if (level == 0) {
                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
-                                ret = btrfs_dec_ref(trans, root, eb, 1);
+                                ret = btrfs_dec_ref(trans, root, eb, 1,
+                                                    wc->for_reloc);
                         else
-                                ret = btrfs_dec_ref(trans, root, eb, 0);
+                                ret = btrfs_dec_ref(trans, root, eb, 0,
+                                                    wc->for_reloc);
                         BUG_ON(ret);
                 }
                 /* make block locked assertion in clean_tree_block happy */
@@ -6449,7 +6464,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
                                btrfs_header_owner(path->nodes[level + 1]));
         }
 
-        btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
+        btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1, 0);
 out:
         wc->refs[level] = 0;
         wc->flags[level] = 0;
@@ -6533,7 +6548,8 @@ static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
  * blocks are properly updated.
  */
 void btrfs_drop_snapshot(struct btrfs_root *root,
-                         struct btrfs_block_rsv *block_rsv, int update_ref)
+                         struct btrfs_block_rsv *block_rsv, int update_ref,
+                         int for_reloc)
 {
         struct btrfs_path *path;
         struct btrfs_trans_handle *trans;
@@ -6621,6 +6637,7 @@ void btrfs_drop_snapshot(struct btrfs_root *root,
         wc->stage = DROP_REFERENCE;
         wc->update_ref = update_ref;
         wc->keep_locks = 0;
+        wc->for_reloc = for_reloc;
         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
 
         while (1) {
@@ -6705,6 +6722,7 @@ out:
  * drop subtree rooted at tree block 'node'.
  *
  * NOTE: this function will unlock and release tree block 'node'
+ * only used by relocation code
  */
 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root,
@@ -6749,6 +6767,7 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
         wc->stage = DROP_REFERENCE;
         wc->update_ref = 0;
         wc->keep_locks = 1;
+        wc->for_reloc = 1;
         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
 
         while (1) {