jbd2: simplify code flow in do_get_write_access()

needs_copy is set only in one place in do_get_write_access(), just move
the frozen buffer copying into that place and factor it out to a
separate function to make do_get_write_access() slightly more readable.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 25 insertions, 24 deletions

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 799242cecffb..2bcb43d770a0 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -755,6 +755,30 @@ static void warn_dirty_buffer(struct buffer_head *bh)
                bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
 }
 
+/* Call t_frozen trigger and copy buffer data into jh->b_frozen_data. */
+static void jbd2_freeze_jh_data(struct journal_head *jh)
+{
+        struct page *page;
+        int offset;
+        char *source;
+        struct buffer_head *bh = jh2bh(jh);
+
+        J_EXPECT_JH(jh, buffer_uptodate(bh), "Possible IO failure.\n");
+        page = bh->b_page;
+        offset = offset_in_page(bh->b_data);
+        source = kmap_atomic(page);
+        /* Fire data frozen trigger just before we copy the data */
+        jbd2_buffer_frozen_trigger(jh, source + offset, jh->b_triggers);
+        memcpy(jh->b_frozen_data, source + offset, bh->b_size);
+        kunmap_atomic(source);
+
+        /*
+         * Now that the frozen data is saved off, we need to store any matching
+         * triggers.
+         */
+        jh->b_frozen_triggers = jh->b_triggers;
+}
+
 /*
  * If the buffer is already part of the current transaction, then there
  * is nothing we need to do.  If it is already part of a prior
@@ -774,7 +798,6 @@ do_get_write_access(handle_t *handle, struct journal_head *jh,
         journal_t *journal;
         int error;
         char *frozen_buffer = NULL;
-        int need_copy = 0;
         unsigned long start_lock, time_lock;
 
         if (is_handle_aborted(handle))
@@ -931,7 +954,7 @@ repeat:
                         }
                         jh->b_frozen_data = frozen_buffer;
                         frozen_buffer = NULL;
-                        need_copy = 1;
+                        jbd2_freeze_jh_data(jh);
                 }
                 jh->b_next_transaction = transaction;
         }
@@ -952,28 +975,6 @@ repeat:
         }
 
 done:
-        if (need_copy) {
-                struct page *page;
-                int offset;
-                char *source;
-
-                J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)),
-                            "Possible IO failure.\n");
-                page = jh2bh(jh)->b_page;
-                offset = offset_in_page(jh2bh(jh)->b_data);
-                source = kmap_atomic(page);
-                /* Fire data frozen trigger just before we copy the data */
-                jbd2_buffer_frozen_trigger(jh, source + offset,
-                                           jh->b_triggers);
-                memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size);
-                kunmap_atomic(source);
-
-                /*
-                 * Now that the frozen data is saved off, we need to store
-                 * any matching triggers.
-                 */
-                jh->b_frozen_triggers = jh->b_triggers;
-        }
         jbd_unlock_bh_state(bh);
 
         /*