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authorJan Schmidt <list.btrfs@jan-o-sch.net>2012-05-29 17:06:54 +0200
committerJan Schmidt <list.btrfs@jan-o-sch.net>2012-05-30 18:18:21 +0200
commit95a06077f7edbd00d32612562be4d857a5b7df54 (patch)
tree664ff2a92a2de3ba96be5a49ac36531d933ee5eb /fs/btrfs
parent20b297d620cd1bb94127942bbb3702fb7b1030b2 (diff)
Btrfs: use delayed ref sequence numbers for all fs-tree updates
The sequence number for delayed refs is needed to postpone certain delayed refs for a very short period while walking backrefs. Before the tree modification log, we thought we'd only have to hold back those references that don't have a counter operation. While now we've the tree mod log, we're rewinding fs tree blocks to a defined consistent state. We cannot know in advance for which tree block we'll be doing rewind operations later. Therefore, we must postpone all the delayed refs for fs-tree blocks, even those having a counter operation. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/ctree.h7
-rw-r--r--fs/btrfs/delayed-ref.c10
-rw-r--r--fs/btrfs/delayed-ref.h19
3 files changed, 13 insertions, 23 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 6ba21b12cec4..f5f11a6c5e92 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3121,4 +3121,11 @@ void btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
struct seq_list *elem);
+static inline int is_fstree(u64 rootid)
+{
+ if (rootid == BTRFS_FS_TREE_OBJECTID ||
+ (s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
+ return 1;
+ return 0;
+}
#endif
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 69f22e3ab3bc..13ae7b04790e 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -525,7 +525,7 @@ static noinline void add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
ref->is_head = 0;
ref->in_tree = 1;
- if (need_ref_seq(for_cow, ref_root))
+ if (is_fstree(ref_root))
seq = inc_delayed_seq(delayed_refs);
ref->seq = seq;
@@ -584,7 +584,7 @@ static noinline void add_delayed_data_ref(struct btrfs_fs_info *fs_info,
ref->is_head = 0;
ref->in_tree = 1;
- if (need_ref_seq(for_cow, ref_root))
+ if (is_fstree(ref_root))
seq = inc_delayed_seq(delayed_refs);
ref->seq = seq;
@@ -658,10 +658,11 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
add_delayed_tree_ref(fs_info, trans, &ref->node, bytenr,
num_bytes, parent, ref_root, level, action,
for_cow);
- if (!need_ref_seq(for_cow, ref_root) &&
+ if (!is_fstree(ref_root) &&
waitqueue_active(&delayed_refs->seq_wait))
wake_up(&delayed_refs->seq_wait);
spin_unlock(&delayed_refs->lock);
+
return 0;
}
@@ -706,10 +707,11 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
add_delayed_data_ref(fs_info, trans, &ref->node, bytenr,
num_bytes, parent, ref_root, owner, offset,
action, for_cow);
- if (!need_ref_seq(for_cow, ref_root) &&
+ if (!is_fstree(ref_root) &&
waitqueue_active(&delayed_refs->seq_wait))
wake_up(&delayed_refs->seq_wait);
spin_unlock(&delayed_refs->lock);
+
return 0;
}
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index fd8244670212..413927fb9957 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -225,25 +225,6 @@ int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
u64 seq);
/*
- * delayed refs with a ref_seq > 0 must be held back during backref walking.
- * this only applies to items in one of the fs-trees. for_cow items never need
- * to be held back, so they won't get a ref_seq number.
- */
-static inline int need_ref_seq(int for_cow, u64 rootid)
-{
- if (for_cow)
- return 0;
-
- if (rootid == BTRFS_FS_TREE_OBJECTID)
- return 1;
-
- if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
- return 1;
-
- return 0;
-}
-
-/*
* a node might live in a head or a regular ref, this lets you
* test for the proper type to use.
*/