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From: Josef Bacik <josef@toxicpanda.com>
To: linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH 03/12] btrfs: add nesting tags to the locking helpers
Date: Thu, 20 Aug 2020 11:46:02 -0400	[thread overview]
Message-ID: <a538e26134d912f4e2e613ce215a4f01bcaf507c.1597938191.git.josef@toxicpanda.com> (raw)
In-Reply-To: <cover.1597938190.git.josef@toxicpanda.com>

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 | 20 +++++++++++++++++++-
 3 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 025a75767d61..41d0685d0e87 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..ffbbd33d8fd7 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -16,12 +16,30 @@
 #define BTRFS_WRITE_LOCK_BLOCKING 3
 #define BTRFS_READ_LOCK_BLOCKING 4
 
+enum btrfs_lock_nesting {
+	BTRFS_NESTING_NORMAL,
+
+	/*
+	 * We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
+	 * add this in here and add a static_assert to keep us from going over
+	 * the limit.  As of this writing we're limited to 8, and we're
+	 * definitely using 8, hence this check to keep us from messing up in
+	 * the future.
+	 */
+	BTRFS_NESTING_MAX,
+};
+
+static_assert(BTRFS_NESTING_MAX <= MAX_LOCKDEP_SUBCLASSES,
+	      "too many lock subclasses defined");
+
 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


  parent reply	other threads:[~2020-08-20 15:46 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
2020-08-20 15:46 ` [PATCH 01/12] btrfs: rename eb->lock_nested to eb->lock_recursed Josef Bacik
2020-08-20 15:46 ` [PATCH 02/12] btrfs: introduce path->recurse Josef Bacik
2020-08-20 15:46 ` Josef Bacik [this message]
2020-08-20 15:46 ` [PATCH 04/12] btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks Josef Bacik
2020-08-20 15:46 ` [PATCH 05/12] btrfs: introduce BTRFS_NESTING_LEFT/BTRFS_NESTING_RIGHT Josef Bacik
2020-08-20 15:46 ` [PATCH 06/12] btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW Josef Bacik
2020-08-20 15:46 ` [PATCH 07/12] btrfs: introduce BTRFS_NESTING_SPLIT for split blocks Josef Bacik
2020-08-20 15:46 ` [PATCH 08/12] btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new roots Josef Bacik
2020-08-20 15:46 ` [PATCH 09/12] btrfs: use BTRFS_NESTED_NEW_ROOT for double splits Josef Bacik
2020-08-20 15:46 ` [PATCH 10/12] btrfs: change our extent buffer lock to a rw_semaphore Josef Bacik
2020-08-20 15:46 ` [PATCH 11/12] btrfs: remove all of the blocking helpers Josef Bacik
2020-08-20 15:46 ` [PATCH 12/12] btrfs: rip out path->leave_spinning Josef Bacik
2020-08-26 14:58 ` [PATCH 00/12] Convert btree locking to an rwsem David Sterba
2020-08-31 22:41   ` David Sterba
2020-11-03 20:59   ` David Sterba

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