[PATCH AUTOSEL 6.0 26/46] btrfs: add lockdep annotations for num_extwriters wait event

Sasha Levin
2022-10-11T14:53:08Z

From: Ioannis Angelakopoulos <iangelak@fb.com>

[ Upstream commit 5a9ba6709f13313984900d635b4c73c9eb7d644e ]

Similarly to the num_writers wait event in fs/btrfs/transaction.c add a
lockdep annotation for the num_extwriters wait event.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Ioannis Angelakopoulos <iangelak@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/ctree.h | 1 +
fs/btrfs/disk-io.c | 1 +
fs/btrfs/transaction.c | 13 +++++++++++++
3 files changed, 15 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 707e644bab92..e886cf639c0f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1097,6 +1097,7 @@ struct btrfs_fs_info {
* compiled without lockdep).
*/
struct lockdep_map btrfs_trans_num_writers_map;
+ struct lockdep_map btrfs_trans_num_extwriters_map;

#ifdef CONFIG_BTRFS_FS_REF_VERIFY
spinlock_t ref_verify_lock;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a04b32f7df9d..811d743e26e6 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2991,6 +2991,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info)
seqlock_init(&fs_info->profiles_lock);

btrfs_lockdep_init_map(fs_info, btrfs_trans_num_writers);
+ btrfs_lockdep_init_map(fs_info, btrfs_trans_num_extwriters);

INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
INIT_LIST_HEAD(&fs_info->space_info);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index b3cb54d852f8..44e47db4c8e8 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -314,6 +314,7 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
extwriter_counter_inc(cur_trans, type);
spin_unlock(&fs_info->trans_lock);
btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
+ btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
return 0;
}
spin_unlock(&fs_info->trans_lock);
@@ -336,6 +337,7 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
return -ENOMEM;

btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
+ btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);

spin_lock(&fs_info->trans_lock);
if (fs_info->running_transaction) {
@@ -343,11 +345,13 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
* someone started a transaction after we unlocked. Make sure
* to redo the checks above
*/
+ btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
kfree(cur_trans);
goto loop;
} else if (BTRFS_FS_ERROR(fs_info)) {
spin_unlock(&fs_info->trans_lock);
+ btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
kfree(cur_trans);
return -EROFS;
@@ -1028,6 +1032,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,

cond_wake_up(&cur_trans->writer_wait);

+ btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(info, btrfs_trans_num_writers);

btrfs_put_transaction(cur_trans);
@@ -2270,6 +2275,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
if (ret)
goto lockdep_release;

+ /*
+ * The thread has started/joined the transaction thus it holds the
+ * lockdep map as a reader. It has to release it before acquiring the
+ * lockdep map as a writer.
+ */
+ btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
+ btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
wait_event(cur_trans->writer_wait,
extwriter_counter_read(cur_trans) == 0);

@@ -2541,6 +2553,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
return ret;

lockdep_release:
+ btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
goto cleanup_transaction;
}
--
2.35.1