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Date: Mon, 30 Sep 2019 12:43:31 +0200
From: Jan Kara <jack@...e.cz>
To: <linux-ext4@...r.kernel.org>
Cc: Ted Tso <tytso@....edu>, Jan Kara <jack@...e.cz>
Subject: [PATCH 13/19] jbd2: Factor out common parts of stopping and restarting a handle
jbd2__journal_restart() has quite some code that is common with
jbd2_journal_stop(). Factor this functionality into stop_this_handle()
helper and use it from both functions. Note that this also drops
t_handle_lock protection from jbd2__journal_restart() as
jbd2_journal_stop() does the same thing without it.
Signed-off-by: Jan Kara <jack@...e.cz>
---
fs/jbd2/transaction.c | 94 +++++++++++++++++++++++----------------------------
1 file changed, 42 insertions(+), 52 deletions(-)
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index ece3e97279c2..8a42c717e260 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -512,12 +512,17 @@ handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
}
EXPORT_SYMBOL(jbd2_journal_start);
-void jbd2_journal_free_reserved(handle_t *handle)
+static void __jbd2_journal_unreserve_handle(handle_t *handle)
{
journal_t *journal = handle->h_journal;
WARN_ON(!handle->h_reserved);
sub_reserved_credits(journal, handle->h_buffer_credits);
+}
+
+void jbd2_journal_free_reserved(handle_t *handle)
+{
+ __jbd2_journal_unreserve_handle(handle);
jbd2_free_handle(handle);
}
EXPORT_SYMBOL(jbd2_journal_free_reserved);
@@ -652,6 +657,28 @@ int jbd2_journal_extend(handle_t *handle, int nblocks)
return result;
}
+static void stop_this_handle(handle_t *handle)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal = transaction->t_journal;
+
+ J_ASSERT(journal_current_handle() == handle);
+ J_ASSERT(atomic_read(&transaction->t_updates) > 0);
+ current->journal_info = NULL;
+ atomic_sub(handle->h_buffer_credits,
+ &transaction->t_outstanding_credits);
+ if (handle->h_rsv_handle)
+ __jbd2_journal_unreserve_handle(handle->h_rsv_handle);
+ if (atomic_dec_and_test(&transaction->t_updates))
+ wake_up(&journal->j_wait_updates);
+
+ rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
+ /*
+ * Scope of the GFP_NOFS context is over here and so we can restore the
+ * original alloc context.
+ */
+ memalloc_nofs_restore(handle->saved_alloc_context);
+}
/**
* int jbd2_journal_restart() - restart a handle .
@@ -674,52 +701,30 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
transaction_t *transaction = handle->h_transaction;
journal_t *journal;
tid_t tid;
- int need_to_start, ret;
+ int need_to_start;
/* If we've had an abort of any type, don't even think about
* actually doing the restart! */
if (is_handle_aborted(handle))
return 0;
journal = transaction->t_journal;
+ tid = transaction->t_tid;
/*
* First unlink the handle from its current transaction, and start the
* commit on that.
*/
- J_ASSERT(atomic_read(&transaction->t_updates) > 0);
- J_ASSERT(journal_current_handle() == handle);
-
- read_lock(&journal->j_state_lock);
- spin_lock(&transaction->t_handle_lock);
- atomic_sub(handle->h_buffer_credits,
- &transaction->t_outstanding_credits);
- if (handle->h_rsv_handle) {
- sub_reserved_credits(journal,
- handle->h_rsv_handle->h_buffer_credits);
- }
- if (atomic_dec_and_test(&transaction->t_updates))
- wake_up(&journal->j_wait_updates);
- tid = transaction->t_tid;
- spin_unlock(&transaction->t_handle_lock);
+ jbd_debug(2, "restarting handle %p\n", handle);
+ stop_this_handle(handle);
handle->h_transaction = NULL;
- current->journal_info = NULL;
- jbd_debug(2, "restarting handle %p\n", handle);
+ read_lock(&journal->j_state_lock);
need_to_start = !tid_geq(journal->j_commit_request, tid);
read_unlock(&journal->j_state_lock);
if (need_to_start)
jbd2_log_start_commit(journal, tid);
-
- rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
handle->h_buffer_credits = nblocks;
- /*
- * Restore the original nofs context because the journal restart
- * is basically the same thing as journal stop and start.
- * start_this_handle will start a new nofs context.
- */
- memalloc_nofs_restore(handle->saved_alloc_context);
- ret = start_this_handle(journal, handle, gfp_mask);
- return ret;
+ return start_this_handle(journal, handle, gfp_mask);
}
EXPORT_SYMBOL(jbd2__journal_restart);
@@ -1715,16 +1720,12 @@ int jbd2_journal_stop(handle_t *handle)
* Handle is already detached from the transaction so there is
* nothing to do other than free the handle.
*/
- if (handle->h_rsv_handle)
- jbd2_free_handle(handle->h_rsv_handle);
+ memalloc_nofs_restore(handle->saved_alloc_context);
goto free_and_exit;
}
journal = transaction->t_journal;
tid = transaction->t_tid;
- J_ASSERT(journal_current_handle() == handle);
- J_ASSERT(atomic_read(&transaction->t_updates) > 0);
-
if (is_handle_aborted(handle))
err = -EIO;
@@ -1794,9 +1795,6 @@ int jbd2_journal_stop(handle_t *handle)
if (handle->h_sync)
transaction->t_synchronous_commit = 1;
- current->journal_info = NULL;
- atomic_sub(handle->h_buffer_credits,
- &transaction->t_outstanding_credits);
/*
* If the handle is marked SYNC, we need to set another commit
@@ -1823,27 +1821,19 @@ int jbd2_journal_stop(handle_t *handle)
}
/*
- * Once we drop t_updates, if it goes to zero the transaction
- * could start committing on us and eventually disappear. So
- * once we do this, we must not dereference transaction
- * pointer again.
+ * Once stop_this_handle() drops t_updates, the transaction could start
+ * committing on us and eventually disappear. So we must not
+ * dereference transaction pointer again after calling
+ * stop_this_handle().
*/
- if (atomic_dec_and_test(&transaction->t_updates))
- wake_up(&journal->j_wait_updates);
-
- rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
+ stop_this_handle(handle);
if (wait_for_commit)
err = jbd2_log_wait_commit(journal, tid);
- if (handle->h_rsv_handle)
- jbd2_journal_free_reserved(handle->h_rsv_handle);
free_and_exit:
- /*
- * Scope of the GFP_NOFS context is over here and so we can restore the
- * original alloc context.
- */
- memalloc_nofs_restore(handle->saved_alloc_context);
+ if (handle->h_rsv_handle)
+ jbd2_free_handle(handle->h_rsv_handle);
jbd2_free_handle(handle);
return err;
}
--
2.16.4
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