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From: Josef Bacik <josef@toxicpanda.com>
To: linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH 12/17] btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW
Date: Mon, 10 Aug 2020 11:42:37 -0400	[thread overview]
Message-ID: <20200810154242.782802-13-josef@toxicpanda.com> (raw)
In-Reply-To: <20200810154242.782802-1-josef@toxicpanda.com>

For similar reasons as BTRFS_NESTING_COW, we need
BTRFS_NESTING_LEFT/RIGHT_COW.  The pattern is this

lock leaf -> BTRFS_NESTING_NORMAL
  cow leaf -> BTRFS_NESTING_COW
    split leaf
      lock left -> BTRFS_NESTING_LEFT
        cow left -> BTRFS_NESTING_LEFT_COW

We need this in order to indicate to lockdep that these locks are
discrete and are being taken in a safe order.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/ctree.c   | 12 ++++++------
 fs/btrfs/locking.h |  8 ++++++++
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index ea5412cd0f62..6b63b3bcacd4 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1900,7 +1900,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		btrfs_set_lock_blocking_write(left);
 		wret = btrfs_cow_block(trans, root, left,
 				       parent, pslot - 1, &left,
-				       BTRFS_NESTING_COW);
+				       BTRFS_NESTING_LEFT_COW);
 		if (wret) {
 			ret = wret;
 			goto enospc;
@@ -1916,7 +1916,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		btrfs_set_lock_blocking_write(right);
 		wret = btrfs_cow_block(trans, root, right,
 				       parent, pslot + 1, &right,
-				       BTRFS_NESTING_COW);
+				       BTRFS_NESTING_RIGHT_COW);
 		if (wret) {
 			ret = wret;
 			goto enospc;
@@ -2085,7 +2085,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 		} else {
 			ret = btrfs_cow_block(trans, root, left, parent,
 					      pslot - 1, &left,
-					      BTRFS_NESTING_COW);
+					      BTRFS_NESTING_LEFT_COW);
 			if (ret)
 				wret = 1;
 			else {
@@ -2140,7 +2140,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 		} else {
 			ret = btrfs_cow_block(trans, root, right,
 					      parent, pslot + 1,
-					      &right, BTRFS_NESTING_COW);
+					      &right, BTRFS_NESTING_RIGHT_COW);
 			if (ret)
 				wret = 1;
 			else {
@@ -3751,7 +3751,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
 
 	/* cow and double check */
 	ret = btrfs_cow_block(trans, root, right, upper,
-			      slot + 1, &right, BTRFS_NESTING_COW);
+			      slot + 1, &right, BTRFS_NESTING_RIGHT_COW);
 	if (ret)
 		goto out_unlock;
 
@@ -3987,7 +3987,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
 	/* cow and double check */
 	ret = btrfs_cow_block(trans, root, left,
 			      path->nodes[1], slot - 1, &left,
-			      BTRFS_NESTING_COW);
+			      BTRFS_NESTING_LEFT_COW);
 	if (ret) {
 		/* we hit -ENOSPC, but it isn't fatal here */
 		if (ret == -ENOSPC)
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index f93e3e10ddbd..31a87477b889 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -38,6 +38,14 @@ enum btrfs_lock_nesting {
 	 */
 	BTRFS_NESTING_LEFT,
 	BTRFS_NESTING_RIGHT,
+
+	/*
+	 * When splitting we will be holding a lock on the left/right node when
+	 * we need to cow that node, thus we need a new set of subclasses for
+	 * these two operations.
+	 */
+	BTRFS_NESTING_LEFT_COW,
+	BTRFS_NESTING_RIGHT_COW,
 };
 
 struct btrfs_path;
-- 
2.24.1


  parent reply	other threads:[~2020-08-10 15:43 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-10 15:42 [PATCH 00/17] Convert to an rwsem for our tree locking Josef Bacik
2020-08-10 15:42 ` [PATCH 01/17] btrfs: drop path before adding new uuid tree entry Josef Bacik
2020-08-10 16:28   ` Filipe Manana
2020-08-10 16:30     ` Filipe Manana
2020-08-11 14:35     ` Josef Bacik
2020-08-10 15:42 ` [PATCH 02/17] btrfs: fix potential deadlock in the search ioctl Josef Bacik
2020-08-10 16:45   ` Filipe Manana
2020-08-10 15:42 ` [PATCH 03/17] btrfs: do not hold device_list_mutex when closing devices Josef Bacik
2020-08-11 10:53   ` Filipe Manana
2020-08-14 14:11   ` David Sterba
2020-08-10 15:42 ` [PATCH 04/17] btrfs: allocate scrub workqueues outside of locks Josef Bacik
2020-08-11 11:22   ` Filipe Manana
2020-08-10 15:42 ` [PATCH 05/17] btrfs: set the correct lockdep class for new nodes Josef Bacik
2020-08-11 11:25   ` Filipe Manana
2020-08-10 15:42 ` [PATCH 06/17] btrfs: set the lockdep class for log tree extent buffers Josef Bacik
2020-08-11 11:28   ` Filipe Manana
2020-08-10 15:42 ` [PATCH 07/17] btrfs: rename eb->lock_nested to eb->lock_recursed Josef Bacik
2020-08-10 15:42 ` [PATCH 08/17] btrfs: introduce path->recurse Josef Bacik
2020-08-10 15:42 ` [PATCH 09/17] btrfs: add nesting tags to the locking helpers Josef Bacik
2020-08-14 14:41   ` David Sterba
2020-08-10 15:42 ` [PATCH 10/17] btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks Josef Bacik
2020-08-10 15:42 ` [PATCH 11/17] btrfs: introduce BTRFS_NESTING_LEFT/BTRFS_NESTING_RIGHT Josef Bacik
2020-08-10 15:42 ` Josef Bacik [this message]
2020-08-10 15:42 ` [PATCH 13/17] btrfs: introduce BTRFS_NESTING_SPLIT for split blocks Josef Bacik
2020-08-10 15:42 ` [PATCH 14/17] btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new roots Josef Bacik
2020-08-14 14:45   ` David Sterba
2020-08-10 15:42 ` [PATCH 15/17] btrfs: change our extent buffer lock to a rw_semaphore Josef Bacik
2020-08-10 15:42 ` [PATCH 16/17] btrfs: remove all of the blocking helpers Josef Bacik
2020-08-10 15:42 ` [PATCH 17/17] btrfs: rip out path->leave_spinning Josef Bacik
2020-08-13 14:26 ` [PATCH 00/17] Convert to an rwsem for our tree locking David Sterba

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