ext4: expand commit callback

index 5802fa1..c65a774 100644
@@ -104,6 +104,78 @@
 #define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
 #define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
 
+/**
+ *   struct ext4_journal_cb_entry - Base structure for callback information.
+ *
+ *   This struct is a 'seed' structure for a using with your own callback
+ *   structs. If you are using callbacks you must allocate one of these
+ *   or another struct of your own definition which has this struct
+ *   as it's first element and pass it to ext4_journal_callback_add().
+ */
+struct ext4_journal_cb_entry {
+	/* list information for other callbacks attached to the same handle */
+	struct list_head jce_list;
+
+	/*  Function to call with this callback structure */
+	void (*jce_func)(struct super_block *sb,
+			 struct ext4_journal_cb_entry *jce, int error);
+
+	/* user data goes here */
+};
+
+/**
+ * ext4_journal_callback_add: add a function to call after transaction commit
+ * @handle: active journal transaction handle to register callback on
+ * @func: callback function to call after the transaction has committed:
+ *        @sb: superblock of current filesystem for transaction
+ *        @jce: returned journal callback data
+ *        @rc: journal state at commit (0 = transaction committed properly)
+ * @jce: journal callback data (internal and function private data struct)
+ *
+ * The registered function will be called in the context of the journal thread
+ * after the transaction for which the handle was created has completed.
+ *
+ * No locks are held when the callback function is called, so it is safe to
+ * call blocking functions from within the callback, but the callback should
+ * not block or run for too long, or the filesystem will be blocked waiting for
+ * the next transaction to commit. No journaling functions can be used, or
+ * there is a risk of deadlock.
+ *
+ * There is no guaranteed calling order of multiple registered callbacks on
+ * the same transaction.
+ */
+static inline void ext4_journal_callback_add(handle_t *handle,
+			void (*func)(struct super_block *sb,
+				     struct ext4_journal_cb_entry *jce,
+				     int rc),
+			struct ext4_journal_cb_entry *jce)
+{
+	struct ext4_sb_info *sbi =
+			EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+	/* Add the jce to transaction's private list */
+	jce->jce_func = func;
+	spin_lock(&sbi->s_md_lock);
+	list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);
+	spin_unlock(&sbi->s_md_lock);
+}
+
+/**
+ * ext4_journal_callback_del: delete a registered callback
+ * @handle: active journal transaction handle on which callback was registered
+ * @jce: registered journal callback entry to unregister
+ */
+static inline void ext4_journal_callback_del(handle_t *handle,
+					     struct ext4_journal_cb_entry *jce)
+{
+	struct ext4_sb_info *sbi =
+			EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+	spin_lock(&sbi->s_md_lock);
+	list_del_init(&jce->jce_list);
+	spin_unlock(&sbi->s_md_lock);
+}
+
 int
 ext4_mark_iloc_dirty(handle_t *handle,
 		     struct inode *inode,

258 lines not on this page · raw message

index 47705f3..7128f46 100644
@@ -96,21 +96,23 @@ extern u8 mb_enable_debug;
 
 
 struct ext4_free_data {
-	/* this links the free block information from group_info */
-	struct rb_node node;
+	/* MUST be the first member */
+	struct ext4_journal_cb_entry	efd_jce;
+
+	/* ext4_free_data private data starts from here */
 
-	/* this links the free block information from ext4_sb_info */
-	struct list_head list;
+	/* this links the free block information from group_info */
+	struct rb_node			efd_node;
 
 	/* group which free block extent belongs */
-	ext4_group_t group;
+	ext4_group_t			efd_group;
 
 	/* free block extent */
-	ext4_grpblk_t start_cluster;
-	ext4_grpblk_t count;
+	ext4_grpblk_t			efd_start_cluster;
+	ext4_grpblk_t			efd_count;
 
 	/* transaction which freed this extent */
-	tid_t	t_tid;
+	tid_t				efd_tid;
 };
 
 struct ext4_prealloc_space {

index 9953d80..f5da954 100644
@@ -431,6 +431,22 @@ static int block_device_ejected(struct super_block *sb)
 	return bdi->dev == NULL;
 }
 
+static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
+{
+	struct super_block		*sb = journal->j_private;
+	struct ext4_sb_info		*sbi = EXT4_SB(sb);
+	int				error = is_journal_aborted(journal);
+	struct ext4_journal_cb_entry	*jce, *tmp;
+
+	spin_lock(&sbi->s_md_lock);
+	list_for_each_entry_safe(jce, tmp, &txn->t_private_list, jce_list) {
+		list_del_init(&jce->jce_list);
+		spin_unlock(&sbi->s_md_lock);
+		jce->jce_func(sb, jce, error);
+		spin_lock(&sbi->s_md_lock);
+	}
+	spin_unlock(&sbi->s_md_lock);
+}
 
 /* Deal with the reporting of failure conditions on a filesystem such as
  * inconsistencies detected or read IO failures.

@@ -3698,6 +3714,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
 
+	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
+
 	/*
 	 * The journal may have updated the bg summary counts, so we
 	 * need to update the global counters.