Btrfs: fix wrong comment in can_overcommit()

[firefly-linux-kernel-4.4.55.git] / fs / btrfs / ctree.c

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index b334362110003165a72b63433b192f2b481c3b01..cdfb4c49a806ad4ba0ebe83b5569a4121a10a220 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -596,6 +596,11 @@ tree_mod_log_insert_move(struct btrfs_fs_info *fs_info,
        if (tree_mod_dont_log(fs_info, eb))
                return 0;
 
+       /*
+        * When we override something during the move, we log these removals.
+        * This can only happen when we move towards the beginning of the
+        * buffer, i.e. dst_slot < src_slot.
+        */
        for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
                ret = tree_mod_log_insert_key_locked(fs_info, eb, i + dst_slot,
                                              MOD_LOG_KEY_REMOVE_WHILE_MOVING);
@@ -647,8 +652,6 @@ tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
        if (tree_mod_dont_log(fs_info, NULL))
                return 0;
 
-       __tree_mod_log_free_eb(fs_info, old_root);
-
        ret = tree_mod_alloc(fs_info, flags, &tm);
        if (ret < 0)
                goto out;
@@ -926,12 +929,7 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
                        ret = btrfs_dec_ref(trans, root, buf, 1, 1);
                        BUG_ON(ret); /* -ENOMEM */
                }
-               /*
-                * don't log freeing in case we're freeing the root node, this
-                * is done by tree_mod_log_set_root_pointer later
-                */
-               if (buf != root->node && btrfs_header_level(buf) != 0)
-                       tree_mod_log_free_eb(root->fs_info, buf);
+               tree_mod_log_free_eb(root->fs_info, buf);
                clean_tree_block(trans, root, buf);
                *last_ref = 1;
        }
@@ -1225,6 +1223,8 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
        free_extent_buffer(eb);
 
        __tree_mod_log_rewind(eb_rewin, time_seq, tm);
+       WARN_ON(btrfs_header_nritems(eb_rewin) >
+               BTRFS_NODEPTRS_PER_BLOCK(fs_info->fs_root));
 
        return eb_rewin;
 }
@@ -1241,9 +1241,11 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
 {
        struct tree_mod_elem *tm;
        struct extent_buffer *eb;
+       struct extent_buffer *old;
        struct tree_mod_root *old_root = NULL;
        u64 old_generation = 0;
        u64 logical;
+       u32 blocksize;
 
        eb = btrfs_read_lock_root_node(root);
        tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
@@ -1259,14 +1261,32 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
        }
 
        tm = tree_mod_log_search(root->fs_info, logical, time_seq);
-       if (old_root)
+       if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
+               btrfs_tree_read_unlock(root->node);
+               free_extent_buffer(root->node);
+               blocksize = btrfs_level_size(root, old_root->level);
+               old = read_tree_block(root, logical, blocksize, 0);
+               if (!old) {
+                       pr_warn("btrfs: failed to read tree block %llu from get_old_root\n",
+                               logical);
+                       WARN_ON(1);
+               } else {
+                       eb = btrfs_clone_extent_buffer(old);
+                       free_extent_buffer(old);
+               }
+       } else if (old_root) {
+               btrfs_tree_read_unlock(root->node);
+               free_extent_buffer(root->node);
                eb = alloc_dummy_extent_buffer(logical, root->nodesize);
-       else
+       } else {
                eb = btrfs_clone_extent_buffer(root->node);
-       btrfs_tree_read_unlock(root->node);
-       free_extent_buffer(root->node);
+               btrfs_tree_read_unlock(root->node);
+               free_extent_buffer(root->node);
+       }
+
        if (!eb)
                return NULL;
+       extent_buffer_get(eb);
        btrfs_tree_read_lock(eb);
        if (old_root) {
                btrfs_set_header_bytenr(eb, eb->start);
@@ -1279,11 +1299,28 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
                __tree_mod_log_rewind(eb, time_seq, tm);
        else
                WARN_ON(btrfs_header_level(eb) != 0);
-       extent_buffer_get(eb);
+       WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(root));
 
        return eb;
 }
 
+int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq)
+{
+       struct tree_mod_elem *tm;
+       int level;
+
+       tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
+       if (tm && tm->op == MOD_LOG_ROOT_REPLACE) {
+               level = tm->old_root.level;
+       } else {
+               rcu_read_lock();
+               level = btrfs_header_level(root->node);
+               rcu_read_unlock();
+       }
+
+       return level;
+}
+
 static inline int should_cow_block(struct btrfs_trans_handle *trans,
                                   struct btrfs_root *root,
                                   struct extent_buffer *buf)
@@ -1725,6 +1762,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
                        goto enospc;
                }
 
+               tree_mod_log_free_eb(root->fs_info, root->node);
                tree_mod_log_set_root_pointer(root, child);
                rcu_assign_pointer(root->node, child);
 
@@ -2970,8 +3008,10 @@ static int push_node_left(struct btrfs_trans_handle *trans,
                           push_items * sizeof(struct btrfs_key_ptr));
 
        if (push_items < src_nritems) {
-               tree_mod_log_eb_move(root->fs_info, src, 0, push_items,
-                                    src_nritems - push_items);
+               /*
+                * don't call tree_mod_log_eb_move here, key removal was already
+                * fully logged by tree_mod_log_eb_copy above.
+                */
                memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
                                      btrfs_node_key_ptr_offset(push_items),
                                      (src_nritems - push_items) *