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>

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 799242c..2bcb43d 100644 (file)
--- 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);
 
        /*