patch-2_6_7-vs1_9_1_12

[linux-2.6.git] / fs / jbd / journal.c

diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c
index 3c95df4..a1e2a5d 100644 (file)
--- a/fs/jbd/journal.c
+++ b/fs/jbd/journal.c
@@ -585,9 +585,13 @@ int journal_bmap(journal_t *journal, unsigned long blocknr,
  * We play buffer_head aliasing tricks to write data/metadata blocks to
  * the journal without copying their contents, but for journal
  * descriptor blocks we do need to generate bona fide buffers.
+ *
+ * After the caller of journal_get_descriptor_buffer() has finished modifying
+ * the buffer's contents they really should run flush_dcache_page(bh->b_page).
+ * But we don't bother doing that, so there will be coherency problems with
+ * mmaps of blockdevs which hold live JBD-controlled filesystems.
  */
-
-struct journal_head * journal_get_descriptor_buffer(journal_t *journal)
+struct journal_head *journal_get_descriptor_buffer(journal_t *journal)
 {
        struct buffer_head *bh;
        unsigned long blocknr;
@@ -599,8 +603,10 @@ struct journal_head * journal_get_descriptor_buffer(journal_t *journal)
                return NULL;
 
        bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
+       lock_buffer(bh);
        memset(bh->b_data, 0, journal->j_blocksize);
-       bh->b_state |= (1 << BH_Dirty);
+       set_buffer_uptodate(bh);
+       unlock_buffer(bh);
        BUFFER_TRACE(bh, "return this buffer");
        return journal_add_journal_head(bh);
 }