diff options
Diffstat (limited to 'fs/jbd')
| -rw-r--r-- | fs/jbd/commit.c | 10 | ||||
| -rw-r--r-- | fs/jbd/transaction.c | 43 |
2 files changed, 36 insertions, 17 deletions
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c index 4bd8825..2c90e3e 100644 --- a/fs/jbd/commit.c +++ b/fs/jbd/commit.c @@ -862,12 +862,12 @@ restart_loop: /* A buffer which has been freed while still being * journaled by a previous transaction may end up still * being dirty here, but we want to avoid writing back - * that buffer in the future now that the last use has - * been committed. That's not only a performance gain, - * it also stops aliasing problems if the buffer is left - * behind for writeback and gets reallocated for another + * that buffer in the future after the "add to orphan" + * operation been committed, That's not only a performance + * gain, it also stops aliasing problems if the buffer is + * left behind for writeback and gets reallocated for another * use in a different page. */ - if (buffer_freed(bh)) { + if (buffer_freed(bh) && !jh->b_next_transaction) { clear_buffer_freed(bh); clear_buffer_jbddirty(bh); } diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c index 57ae203..5ae71e7 100644 --- a/fs/jbd/transaction.c +++ b/fs/jbd/transaction.c @@ -1864,6 +1864,21 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh) if (!jh) goto zap_buffer_no_jh; + /* + * We cannot remove the buffer from checkpoint lists until the + * transaction adding inode to orphan list (let's call it T) + * is committed. Otherwise if the transaction changing the + * buffer would be cleaned from the journal before T is + * committed, a crash will cause that the correct contents of + * the buffer will be lost. On the other hand we have to + * clear the buffer dirty bit at latest at the moment when the + * transaction marking the buffer as freed in the filesystem + * structures is committed because from that moment on the + * buffer can be reallocated and used by a different page. + * Since the block hasn't been freed yet but the inode has + * already been added to orphan list, it is safe for us to add + * the buffer to BJ_Forget list of the newest transaction. + */ transaction = jh->b_transaction; if (transaction == NULL) { /* First case: not on any transaction. If it @@ -1929,16 +1944,15 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh) goto zap_buffer; } /* - * If it is committing, we simply cannot touch it. We - * can remove it's next_transaction pointer from the - * running transaction if that is set, but nothing - * else. */ + * The buffer is committing, we simply cannot touch + * it. So we just set j_next_transaction to the + * running transaction (if there is one) and mark + * buffer as freed so that commit code knows it should + * clear dirty bits when it is done with the buffer. + */ set_buffer_freed(bh); - if (jh->b_next_transaction) { - J_ASSERT(jh->b_next_transaction == - journal->j_running_transaction); - jh->b_next_transaction = NULL; - } + if (journal->j_running_transaction && buffer_jbddirty(bh)) + jh->b_next_transaction = journal->j_running_transaction; journal_put_journal_head(jh); spin_unlock(&journal->j_list_lock); jbd_unlock_bh_state(bh); @@ -2120,7 +2134,7 @@ void journal_file_buffer(struct journal_head *jh, */ void __journal_refile_buffer(struct journal_head *jh) { - int was_dirty; + int was_dirty, jlist; struct buffer_head *bh = jh2bh(jh); J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); @@ -2142,8 +2156,13 @@ void __journal_refile_buffer(struct journal_head *jh) __journal_temp_unlink_buffer(jh); jh->b_transaction = jh->b_next_transaction; jh->b_next_transaction = NULL; - __journal_file_buffer(jh, jh->b_transaction, - jh->b_modified ? BJ_Metadata : BJ_Reserved); + if (buffer_freed(bh)) + jlist = BJ_Forget; + else if (jh->b_modified) + jlist = BJ_Metadata; + else + jlist = BJ_Reserved; + __journal_file_buffer(jh, jh->b_transaction, jlist); J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); if (was_dirty) |