diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/jbd2/transaction.c | 130 |
1 files changed, 59 insertions, 71 deletions
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 3b2e617baab6..1bbcf86499c9 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -884,6 +884,20 @@ repeat: jh->b_modified = 0; /* + * If the buffer is not journaled right now, we need to make sure it + * doesn't get written to disk before the caller actually commits the + * new data + */ + if (!jh->b_transaction) { + JBUFFER_TRACE(jh, "no transaction"); + J_ASSERT_JH(jh, !jh->b_next_transaction); + JBUFFER_TRACE(jh, "file as BJ_Reserved"); + spin_lock(&journal->j_list_lock); + __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); + spin_unlock(&journal->j_list_lock); + goto done; + } + /* * If there is already a copy-out version of this buffer, then we don't * need to make another one */ @@ -894,84 +908,58 @@ repeat: goto done; } - /* Is there data here we need to preserve? */ + JBUFFER_TRACE(jh, "owned by older transaction"); + J_ASSERT_JH(jh, jh->b_next_transaction == NULL); + J_ASSERT_JH(jh, jh->b_transaction == journal->j_committing_transaction); - if (jh->b_transaction && jh->b_transaction != transaction) { - JBUFFER_TRACE(jh, "owned by older transaction"); - J_ASSERT_JH(jh, jh->b_next_transaction == NULL); - J_ASSERT_JH(jh, jh->b_transaction == - journal->j_committing_transaction); + /* + * There is one case we have to be very careful about. If the + * committing transaction is currently writing this buffer out to disk + * and has NOT made a copy-out, then we cannot modify the buffer + * contents at all right now. The essence of copy-out is that it is + * the extra copy, not the primary copy, which gets journaled. If the + * primary copy is already going to disk then we cannot do copy-out + * here. + */ + if (buffer_shadow(bh)) { + JBUFFER_TRACE(jh, "on shadow: sleep"); + jbd_unlock_bh_state(bh); + wait_on_bit_io(&bh->b_state, BH_Shadow, TASK_UNINTERRUPTIBLE); + goto repeat; + } - /* There is one case we have to be very careful about. - * If the committing transaction is currently writing - * this buffer out to disk and has NOT made a copy-out, - * then we cannot modify the buffer contents at all - * right now. The essence of copy-out is that it is the - * extra copy, not the primary copy, which gets - * journaled. If the primary copy is already going to - * disk then we cannot do copy-out here. */ - - if (buffer_shadow(bh)) { - JBUFFER_TRACE(jh, "on shadow: sleep"); + /* + * Only do the copy if the currently-owning transaction still needs it. + * If buffer isn't on BJ_Metadata list, the committing transaction is + * past that stage (here we use the fact that BH_Shadow is set under + * bh_state lock together with refiling to BJ_Shadow list and at this + * point we know the buffer doesn't have BH_Shadow set). + * + * Subtle point, though: if this is a get_undo_access, then we will be + * relying on the frozen_data to contain the new value of the + * committed_data record after the transaction, so we HAVE to force the + * frozen_data copy in that case. + */ + if (jh->b_jlist == BJ_Metadata || force_copy) { + JBUFFER_TRACE(jh, "generate frozen data"); + if (!frozen_buffer) { + JBUFFER_TRACE(jh, "allocate memory for buffer"); jbd_unlock_bh_state(bh); - wait_on_bit_io(&bh->b_state, BH_Shadow, - TASK_UNINTERRUPTIBLE); - goto repeat; - } - - /* - * Only do the copy if the currently-owning transaction still - * needs it. If buffer isn't on BJ_Metadata list, the - * committing transaction is past that stage (here we use the - * fact that BH_Shadow is set under bh_state lock together with - * refiling to BJ_Shadow list and at this point we know the - * buffer doesn't have BH_Shadow set). - * - * Subtle point, though: if this is a get_undo_access, - * then we will be relying on the frozen_data to contain - * the new value of the committed_data record after the - * transaction, so we HAVE to force the frozen_data copy - * in that case. - */ - if (jh->b_jlist == BJ_Metadata || force_copy) { - JBUFFER_TRACE(jh, "generate frozen data"); + frozen_buffer = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS); if (!frozen_buffer) { - JBUFFER_TRACE(jh, "allocate memory for buffer"); - jbd_unlock_bh_state(bh); - frozen_buffer = - jbd2_alloc(jh2bh(jh)->b_size, - GFP_NOFS); - if (!frozen_buffer) { - printk(KERN_ERR - "%s: OOM for frozen_buffer\n", - __func__); - JBUFFER_TRACE(jh, "oom!"); - error = -ENOMEM; - goto out; - } - goto repeat; + printk(KERN_ERR "%s: OOM for frozen_buffer\n", + __func__); + JBUFFER_TRACE(jh, "oom!"); + error = -ENOMEM; + goto out; } - jh->b_frozen_data = frozen_buffer; - frozen_buffer = NULL; - jbd2_freeze_jh_data(jh); + goto repeat; } - jh->b_next_transaction = transaction; - } - - - /* - * Finally, if the buffer is not journaled right now, we need to make - * sure it doesn't get written to disk before the caller actually - * commits the new data - */ - if (!jh->b_transaction) { - JBUFFER_TRACE(jh, "no transaction"); - J_ASSERT_JH(jh, !jh->b_next_transaction); - JBUFFER_TRACE(jh, "file as BJ_Reserved"); - spin_lock(&journal->j_list_lock); - __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); - spin_unlock(&journal->j_list_lock); + jh->b_frozen_data = frozen_buffer; + frozen_buffer = NULL; + jbd2_freeze_jh_data(jh); } + jh->b_next_transaction = transaction; done: jbd_unlock_bh_state(bh); |