diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 97f22ff8326f0a0ab7c60d27b70d2258455b5db5..94ecac33cf2d924ab55cff813b774c04acd285a9 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -100,38 +100,83 @@ struct async_submit_bio {
struct btrfs_work work;
};
-/* These are used to set the lockdep class on the extent buffer locks.
- * The class is set by the readpage_end_io_hook after the buffer has
- * passed csum validation but before the pages are unlocked.
+/*
+ * Lockdep class keys for extent_buffer->lock's in this root. For a given
+ * eb, the lockdep key is determined by the btrfs_root it belongs to and
+ * the level the eb occupies in the tree.
+ *
+ * Different roots are used for different purposes and may nest inside each
+ * other and they require separate keysets. As lockdep keys should be
+ * static, assign keysets according to the purpose of the root as indicated
+ * by btrfs_root->objectid. This ensures that all special purpose roots
+ * have separate keysets.
*
- * The lockdep class is also set by btrfs_init_new_buffer on freshly
- * allocated blocks.
+ * Lock-nesting across peer nodes is always done with the immediate parent
+ * node locked thus preventing deadlock. As lockdep doesn't know this, use
+ * subclass to avoid triggering lockdep warning in such cases.
*
- * The class is based on the level in the tree block, which allows lockdep
- * to know that lower nodes nest inside the locks of higher nodes.
+ * The key is set by the readpage_end_io_hook after the buffer has passed
+ * csum validation but before the pages are unlocked. It is also set by
+ * btrfs_init_new_buffer on freshly allocated blocks.
*
- * We also add a check to make sure the highest level of the tree is
- * the same as our lockdep setup here. If BTRFS_MAX_LEVEL changes, this
- * code needs update as well.
+ * We also add a check to make sure the highest level of the tree is the
+ * same as our lockdep setup here. If BTRFS_MAX_LEVEL changes, this code
+ * needs update as well.
*/
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# if BTRFS_MAX_LEVEL != 8
# error
# endif
-static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
-static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
- /* leaf */
- "btrfs-extent-00",
- "btrfs-extent-01",
- "btrfs-extent-02",
- "btrfs-extent-03",
- "btrfs-extent-04",
- "btrfs-extent-05",
- "btrfs-extent-06",
- "btrfs-extent-07",
- /* highest possible level */
- "btrfs-extent-08",
+
+static struct btrfs_lockdep_keyset {
+ u64 id; /* root objectid */
+ const char *name_stem; /* lock name stem */
+ char names[BTRFS_MAX_LEVEL + 1][20];
+ struct lock_class_key keys[BTRFS_MAX_LEVEL + 1];
+} btrfs_lockdep_keysets[] = {
+ { .id = BTRFS_ROOT_TREE_OBJECTID, .name_stem = "root" },
+ { .id = BTRFS_EXTENT_TREE_OBJECTID, .name_stem = "extent" },
+ { .id = BTRFS_CHUNK_TREE_OBJECTID, .name_stem = "chunk" },
+ { .id = BTRFS_DEV_TREE_OBJECTID, .name_stem = "dev" },
+ { .id = BTRFS_FS_TREE_OBJECTID, .name_stem = "fs" },
+ { .id = BTRFS_CSUM_TREE_OBJECTID, .name_stem = "csum" },
+ { .id = BTRFS_ORPHAN_OBJECTID, .name_stem = "orphan" },
+ { .id = BTRFS_TREE_LOG_OBJECTID, .name_stem = "log" },
+ { .id = BTRFS_TREE_RELOC_OBJECTID, .name_stem = "treloc" },
+ { .id = BTRFS_DATA_RELOC_TREE_OBJECTID, .name_stem = "dreloc" },
+ { .id = 0, .name_stem = "tree" },
};
+
+void __init btrfs_init_lockdep(void)
+{
+ int i, j;
+
+ /* initialize lockdep class names */
+ for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
+ struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
+
+ for (j = 0; j < ARRAY_SIZE(ks->names); j++)
+ snprintf(ks->names[j], sizeof(ks->names[j]),
+ "btrfs-%s-%02d", ks->name_stem, j);
+ }
+}
+
+void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
+ int level)
+{
+ struct btrfs_lockdep_keyset *ks;
+
+ BUG_ON(level >= ARRAY_SIZE(ks->keys));
+
+ /* find the matching keyset, id 0 is the default entry */
+ for (ks = btrfs_lockdep_keysets; ks->id; ks++)
+ if (ks->id == objectid)
+ break;
+
+ lockdep_set_class_and_name(&eb->lock,
+ &ks->keys[level], ks->names[level]);
+}
+
#endif
/*
@@ -491,15 +536,6 @@ static noinline int check_leaf(struct btrfs_root *root,
return 0;
}
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
-{
- lockdep_set_class_and_name(&eb->lock,
- &btrfs_eb_class[level],
- btrfs_eb_name[level]);
-}
-#endif
-
static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
struct extent_state *state)
{
@@ -550,7 +586,8 @@ static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
}
found_level = btrfs_header_level(eb);
- btrfs_set_buffer_lockdep_class(eb, found_level);
+ btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
+ eb, found_level);
ret = csum_tree_block(root, eb, 1);
if (ret) {
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index a0b610a67aaeadf1f564d03e218305997c021a85..bec3ea4bd67fd465a8a5e008fcae1e7353f573ad 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -87,10 +87,14 @@ int btree_lock_page_hook(struct page *page);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
-void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level);
+void btrfs_init_lockdep(void);
+void btrfs_set_buffer_lockdep_class(u64 objectid,
+ struct extent_buffer *eb, int level);
#else
-static inline void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb,
- int level)
+static inline void btrfs_init_lockdep(void)
+{ }
+static inline void btrfs_set_buffer_lockdep_class(u64 objectid,
+ struct extent_buffer *eb, int level)
{
}
#endif
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2a782c2fcb622153b54b09c373601cf34ce31b96..06a5ee29b4463b24f80adac8e70928c0a9fe5903 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5625,7 +5625,7 @@ struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
if (!buf)
return ERR_PTR(-ENOMEM);
btrfs_set_header_generation(buf, trans->transid);
- btrfs_set_buffer_lockdep_class(buf, level);
+ btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
btrfs_tree_lock(buf);
clean_tree_block(trans, root, buf);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 19450bc536327c77f7add37e723b668da410eedd..b89e372c75449bf228f7ca6eb5904d5b00474b90 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3595,7 +3595,7 @@ int btrfs_read_sys_array(struct btrfs_root *root)
if (!sb)
return -ENOMEM;
btrfs_set_buffer_uptodate(sb);
- btrfs_set_buffer_lockdep_class(sb, 0);
+ btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
array_size = btrfs_super_sys_array_size(super_copy);