[PATCH 09/17] btrfs: add nesting tags to the locking helpers

Josef Bacik
2020-08-10T15:43:10Z

We will need these when we switch to an rwsem, so plumb in the
infrastructure here to use later on. I violate the 80 character limit
some here because it'll be cleaned up later.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 11 ++++++++---
fs/btrfs/locking.c | 14 ++++++++++----
fs/btrfs/locking.h | 8 +++++++-
3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 34d40b19bb71..fefc61402118 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2875,7 +2875,8 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
} else {
if (!btrfs_tree_read_lock_atomic(b)) {
btrfs_set_path_blocking(p);
- __btrfs_tree_read_lock(b, p->recurse);
+ __btrfs_tree_read_lock(b, BTRFS_NESTING_NORMAL,
+ p->recurse);
}
p->locks[level] = BTRFS_READ_LOCK;
}
@@ -5379,7 +5380,9 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
}
if (!ret) {
btrfs_set_path_blocking(path);
- __btrfs_tree_read_lock(next, path->recurse);
+ __btrfs_tree_read_lock(next,
+ BTRFS_NESTING_NORMAL,
+ path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
}
@@ -5414,7 +5417,9 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
ret = btrfs_try_tree_read_lock(next);
if (!ret) {
btrfs_set_path_blocking(path);
- __btrfs_tree_read_lock(next, path->recurse);
+ __btrfs_tree_read_lock(next,
+ BTRFS_NESTING_NORMAL,
+ path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
}
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index d07818733833..133a6dd5f29b 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -244,7 +244,8 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
*
* The rwlock is held upon exit.
*/
-void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse)
+void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest,
+ bool recurse)
{
u64 start_ns = 0;

@@ -282,7 +283,7 @@ void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse)

void btrfs_tree_read_lock(struct extent_buffer *eb)
{
- __btrfs_tree_read_lock(eb, false);
+ __btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, false);
}

/*
@@ -415,7 +416,7 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
*
* The rwlock is held for write upon exit.
*/
-void btrfs_tree_lock(struct extent_buffer *eb)
+void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
__acquires(&eb->lock)
{
u64 start_ns = 0;
@@ -440,6 +441,11 @@ void btrfs_tree_lock(struct extent_buffer *eb)
trace_btrfs_tree_lock(eb, start_ns);
}

+void btrfs_tree_lock(struct extent_buffer *eb)
+{
+ __btrfs_tree_lock(eb, BTRFS_NESTING_NORMAL);
+}
+
/*
* Release the write lock, either blocking or spinning (ie. there's no need
* for an explicit blocking unlock, like btrfs_tree_read_unlock_blocking).
@@ -565,7 +571,7 @@ struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root,

while (1) {
eb = btrfs_root_node(root);
- __btrfs_tree_read_lock(eb, recurse);
+ __btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, recurse);
if (eb == root->node)
break;
btrfs_tree_read_unlock(eb);
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 587f144adafe..476b5552e8b2 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -16,12 +16,18 @@
#define BTRFS_WRITE_LOCK_BLOCKING 3
#define BTRFS_READ_LOCK_BLOCKING 4

+enum btrfs_lock_nesting {
+ BTRFS_NESTING_NORMAL = 0,
+};
+
struct btrfs_path;

+void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest);
void btrfs_tree_lock(struct extent_buffer *eb);
void btrfs_tree_unlock(struct extent_buffer *eb);

-void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse);
+void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest,
+ bool recurse);
void btrfs_tree_read_lock(struct extent_buffer *eb);
void btrfs_tree_read_unlock(struct extent_buffer *eb);
void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
--
2.24.1