diff mbox series

[3/3] btrfs: add and use helpers to get and set an inode's delayed_node

Message ID 48ccb776f018f79730fb9b9139623960401f9505.1715951291.git.fdmanana@suse.com (mailing list archive)
State New
Headers show
Series btrfs: avoid data races when accessing an inode's delayed_node | expand

Commit Message

Filipe Manana May 17, 2024, 1:13 p.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

When reading the delayed_node of an inode without taking the lock of the
root->delayed_nodes we are using READ_ONCE(), and when updating it we are
using WRITE_ONCE().

Add and use helpers that hide the usage of READ_ONCE() and WRITE_ONCE(),
like we do for other inode fields such as first_dir_index_to_log or the
log_transid field of struct btrfs_root for example.

Also make use of the setter helper at btrfs_alloc_inode() for consistency
only - it shouldn't be needed since when allocating an inode no one else
can access it concurrently.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/btrfs_inode.h   | 12 ++++++++++++
 fs/btrfs/delayed-inode.c | 10 +++++-----
 fs/btrfs/inode.c         |  4 ++--
 3 files changed, 19 insertions(+), 7 deletions(-)

Comments

Qu Wenruo May 17, 2024, 10:51 p.m. UTC | #1 
在 2024/5/17 22:43, fdmanana@kernel.org 写道:
> From: Filipe Manana <fdmanana@suse.com>
>
> When reading the delayed_node of an inode without taking the lock of the
> root->delayed_nodes we are using READ_ONCE(), and when updating it we are
> using WRITE_ONCE().
>
> Add and use helpers that hide the usage of READ_ONCE() and WRITE_ONCE(),
> like we do for other inode fields such as first_dir_index_to_log or the
> log_transid field of struct btrfs_root for example.
>
> Also make use of the setter helper at btrfs_alloc_inode() for consistency
> only - it shouldn't be needed since when allocating an inode no one else
> can access it concurrently.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu

> ---
>   fs/btrfs/btrfs_inode.h   | 12 ++++++++++++
>   fs/btrfs/delayed-inode.c | 10 +++++-----
>   fs/btrfs/inode.c         |  4 ++--
>   3 files changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
> index 4d9299789a03..3c8bc7a8ebdd 100644
> --- a/fs/btrfs/btrfs_inode.h
> +++ b/fs/btrfs/btrfs_inode.h
> @@ -330,6 +330,18 @@ struct btrfs_inode {
>   	struct inode vfs_inode;
>   };
>
> +static inline struct btrfs_delayed_node *btrfs_get_inode_delayed_node(
> +					      const struct btrfs_inode *inode)
> +{
> +	return READ_ONCE(inode->delayed_node);
> +}
> +
> +static inline void btrfs_set_inode_delayed_node(struct btrfs_inode *inode,
> +						struct btrfs_delayed_node *node)
> +{
> +	WRITE_ONCE(inode->delayed_node, node);
> +}
> +
>   static inline u64 btrfs_get_first_dir_index_to_log(const struct btrfs_inode *inode)
>   {
>   	return READ_ONCE(inode->first_dir_index_to_log);
> diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
> index 6df7e44d9d31..f2fe488665e8 100644
> --- a/fs/btrfs/delayed-inode.c
> +++ b/fs/btrfs/delayed-inode.c
> @@ -71,7 +71,7 @@ static struct btrfs_delayed_node *btrfs_get_delayed_node(
>   	u64 ino = btrfs_ino(btrfs_inode);
>   	struct btrfs_delayed_node *node;
>
> -	node = READ_ONCE(btrfs_inode->delayed_node);
> +	node = btrfs_get_inode_delayed_node(btrfs_inode);
>   	if (node) {
>   		refcount_inc(&node->refs);
>   		return node;
> @@ -106,7 +106,7 @@ static struct btrfs_delayed_node *btrfs_get_delayed_node(
>   		 */
>   		if (refcount_inc_not_zero(&node->refs)) {
>   			refcount_inc(&node->refs);
> -			WRITE_ONCE(btrfs_inode->delayed_node, node);
> +			btrfs_set_inode_delayed_node(btrfs_inode, node);
>   		} else {
>   			node = NULL;
>   		}
> @@ -161,7 +161,7 @@ static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
>   	ASSERT(xa_err(ptr) != -EINVAL);
>   	ASSERT(xa_err(ptr) != -ENOMEM);
>   	ASSERT(ptr == NULL);
> -	WRITE_ONCE(btrfs_inode->delayed_node, node);
> +	btrfs_set_inode_delayed_node(btrfs_inode, node);
>   	xa_unlock(&root->delayed_nodes);
>
>   	return node;
> @@ -1308,11 +1308,11 @@ void btrfs_remove_delayed_node(struct btrfs_inode *inode)
>   {
>   	struct btrfs_delayed_node *delayed_node;
>
> -	delayed_node = READ_ONCE(inode->delayed_node);
> +	delayed_node = btrfs_get_inode_delayed_node(inode);
>   	if (!delayed_node)
>   		return;
>
> -	WRITE_ONCE(inode->delayed_node, NULL);
> +	btrfs_set_inode_delayed_node(inode, NULL);
>   	btrfs_release_delayed_node(delayed_node);
>   }
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 11cad22d7b4c..2f3129fe0e58 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -6100,7 +6100,7 @@ static int btrfs_dirty_inode(struct btrfs_inode *inode)
>   		ret = btrfs_update_inode(trans, inode);
>   	}
>   	btrfs_end_transaction(trans);
> -	if (READ_ONCE(inode->delayed_node))
> +	if (btrfs_get_inode_delayed_node(inode))
>   		btrfs_balance_delayed_items(fs_info);
>
>   	return ret;
> @@ -8475,7 +8475,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
>   	ei->prop_compress = BTRFS_COMPRESS_NONE;
>   	ei->defrag_compress = BTRFS_COMPRESS_NONE;
>
> -	ei->delayed_node = NULL;
> +	btrfs_set_inode_delayed_node(ei, NULL);
>
>   	ei->i_otime_sec = 0;
>   	ei->i_otime_nsec = 0;
diff mbox series

Patch

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 4d9299789a03..3c8bc7a8ebdd 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -330,6 +330,18 @@  struct btrfs_inode {
 	struct inode vfs_inode;
 };
 
+static inline struct btrfs_delayed_node *btrfs_get_inode_delayed_node(
+					      const struct btrfs_inode *inode)
+{
+	return READ_ONCE(inode->delayed_node);
+}
+
+static inline void btrfs_set_inode_delayed_node(struct btrfs_inode *inode,
+						struct btrfs_delayed_node *node)
+{
+	WRITE_ONCE(inode->delayed_node, node);
+}
+
 static inline u64 btrfs_get_first_dir_index_to_log(const struct btrfs_inode *inode)
 {
 	return READ_ONCE(inode->first_dir_index_to_log);
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 6df7e44d9d31..f2fe488665e8 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -71,7 +71,7 @@  static struct btrfs_delayed_node *btrfs_get_delayed_node(
 	u64 ino = btrfs_ino(btrfs_inode);
 	struct btrfs_delayed_node *node;
 
-	node = READ_ONCE(btrfs_inode->delayed_node);
+	node = btrfs_get_inode_delayed_node(btrfs_inode);
 	if (node) {
 		refcount_inc(&node->refs);
 		return node;
@@ -106,7 +106,7 @@  static struct btrfs_delayed_node *btrfs_get_delayed_node(
 		 */
 		if (refcount_inc_not_zero(&node->refs)) {
 			refcount_inc(&node->refs);
-			WRITE_ONCE(btrfs_inode->delayed_node, node);
+			btrfs_set_inode_delayed_node(btrfs_inode, node);
 		} else {
 			node = NULL;
 		}
@@ -161,7 +161,7 @@  static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
 	ASSERT(xa_err(ptr) != -EINVAL);
 	ASSERT(xa_err(ptr) != -ENOMEM);
 	ASSERT(ptr == NULL);
-	WRITE_ONCE(btrfs_inode->delayed_node, node);
+	btrfs_set_inode_delayed_node(btrfs_inode, node);
 	xa_unlock(&root->delayed_nodes);
 
 	return node;
@@ -1308,11 +1308,11 @@  void btrfs_remove_delayed_node(struct btrfs_inode *inode)
 {
 	struct btrfs_delayed_node *delayed_node;
 
-	delayed_node = READ_ONCE(inode->delayed_node);
+	delayed_node = btrfs_get_inode_delayed_node(inode);
 	if (!delayed_node)
 		return;
 
-	WRITE_ONCE(inode->delayed_node, NULL);
+	btrfs_set_inode_delayed_node(inode, NULL);
 	btrfs_release_delayed_node(delayed_node);
 }
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 11cad22d7b4c..2f3129fe0e58 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6100,7 +6100,7 @@  static int btrfs_dirty_inode(struct btrfs_inode *inode)
 		ret = btrfs_update_inode(trans, inode);
 	}
 	btrfs_end_transaction(trans);
-	if (READ_ONCE(inode->delayed_node))
+	if (btrfs_get_inode_delayed_node(inode))
 		btrfs_balance_delayed_items(fs_info);
 
 	return ret;
@@ -8475,7 +8475,7 @@  struct inode *btrfs_alloc_inode(struct super_block *sb)
 	ei->prop_compress = BTRFS_COMPRESS_NONE;
 	ei->defrag_compress = BTRFS_COMPRESS_NONE;
 
-	ei->delayed_node = NULL;
+	btrfs_set_inode_delayed_node(ei, NULL);
 
 	ei->i_otime_sec = 0;
 	ei->i_otime_nsec = 0;