void journal_forget (handle_t *handle, struct buffer_head *bh)
{
journal_t * journal = handle->h_transaction->t_journal;
J_ASSERT (!test_and_set_bit(BH_Freed, &bh->b_state));
clear_bit(BH_Alloced, &bh->b_state);
/* @@@ DEBUG: This is just buffer debug state: we can do this
without a journal lock... */
if (handle->h_transaction->t_tid == bh->b_alloc_transaction) {
bh->b_alloc_transaction = 0;
set_bit(BH_QuickFree, &bh->b_state);
}
bh->b_free2_transaction = bh->b_free_transaction;
bh->b_free_transaction = handle->h_transaction->t_tid;
/* If we can't lock the journal because somebody else already
* has the lock, then just release the buffer: that's better
* than changing the semantics of bforget() to include a possible
* context switch. */
if (try_lock_journal(journal))
goto nolock;
if (bh->b_transaction == handle->h_transaction) {
J_ASSERT(!bh->b_frozen_data);
/* If we are forgetting a buffer which is already part
* of this transaction, then we can just drop it from
* the transaction immediately. */
clear_bit(BH_Dirty, &bh->b_state);
clear_bit(BH_JDirty, &bh->b_state);
journal_unfile_buffer(bh);
bh->b_transaction = 0;
} else if (bh->b_transaction) {
/* However, if the buffer is still owned by a prior
* (committing) transaction, we can't do anything with
* it right now. */
unlock_journal(journal);
brelse(bh);
return;
}
J_ASSERT(!bh->b_frozen_data);
J_ASSERT(!bh->b_committed_data);
unlock_journal(journal);
/* @@@ DEBUG ONLY. Eventually we will indeed want to be able to
* discard forgotten buffers a bit more intelligently. */
nolock:
brelse(bh);
return;
#if 0
/* Now we know that the buffer isn't being committed anywhere,
* but it might still be on a transaction's checkpoint list. If
* so, we want to place it on the new transaction's forget list:
* on commit it will undo the old checkpoint. Remember, we have
* to be able to unwind the forget() if we take a crash before
* the commit! */
if (bh->b_cp_transaction) {
journal_file_buffer(bh, handle->h_transaction, BJ_Forget);
bh->b_transaction = handle->h_transaction;
brelse(bh);
} else
__bforget(bh);
#endif
}
int journal_forget (handle_t *handle, struct buffer_head *bh)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
struct journal_head *jh;
int drop_reserve = 0;
int err = 0;
int was_modified = 0;
BUFFER_TRACE(bh, "entry");
jbd_lock_bh_state(bh);
spin_lock(&journal->j_list_lock);
if (!buffer_jbd(bh))
goto not_jbd;
jh = bh2jh(bh);
/* Critical error: attempting to delete a bitmap buffer, maybe?
* Don't do any jbd operations, and return an error. */
if (!J_EXPECT_JH(jh, !jh->b_committed_data,
"inconsistent data on disk")) {
err = -EIO;
goto not_jbd;
}
/* keep track of wether or not this transaction modified us */
was_modified = jh->b_modified;
/*
* The buffer's going from the transaction, we must drop
* all references -bzzz
*/
jh->b_modified = 0;
if (jh->b_transaction == handle->h_transaction) {
J_ASSERT_JH(jh, !jh->b_frozen_data);
/* If we are forgetting a buffer which is already part
* of this transaction, then we can just drop it from
* the transaction immediately. */
clear_buffer_dirty(bh);
clear_buffer_jbddirty(bh);
JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
/*
* we only want to drop a reference if this transaction
* modified the buffer
*/
if (was_modified)
drop_reserve = 1;
/*
* We are no longer going to journal this buffer.
* However, the commit of this transaction is still
* important to the buffer: the delete that we are now
* processing might obsolete an old log entry, so by
* committing, we can satisfy the buffer's checkpoint.
*
* So, if we have a checkpoint on the buffer, we should
* now refile the buffer on our BJ_Forget list so that
* we know to remove the checkpoint after we commit.
*/
if (jh->b_cp_transaction) {
__journal_temp_unlink_buffer(jh);
__journal_file_buffer(jh, transaction, BJ_Forget);
} else {
__journal_unfile_buffer(jh);
journal_remove_journal_head(bh);
__brelse(bh);
if (!buffer_jbd(bh)) {
spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh);
__bforget(bh);
goto drop;
}
}
} else if (jh->b_transaction) {
J_ASSERT_JH(jh, (jh->b_transaction ==
journal->j_committing_transaction));
/* However, if the buffer is still owned by a prior
* (committing) transaction, we can't drop it yet... */
JBUFFER_TRACE(jh, "belongs to older transaction");
/* ... but we CAN drop it from the new transaction if we
* have also modified it since the original commit. */
if (jh->b_next_transaction) {
J_ASSERT(jh->b_next_transaction == transaction);
jh->b_next_transaction = NULL;
/*
* only drop a reference if this transaction modified
* the buffer
*/
if (was_modified)
drop_reserve = 1;
}
}
not_jbd:
spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh);
__brelse(bh);
drop:
if (drop_reserve) {
/* no need to reserve log space for this block -bzzz */
handle->h_buffer_credits++;
}
return err;
}
int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
struct journal_head *jh;
int drop_reserve = 0;
int err = 0;
int was_modified = 0;
BUFFER_TRACE(bh, "entry");
jbd_lock_bh_state(bh);
spin_lock(&journal->j_list_lock);
if (!buffer_jbd(bh))
goto not_jbd;
jh = bh2jh(bh);
if (!J_EXPECT_JH(jh, !jh->b_committed_data,
"inconsistent data on disk")) {
err = -EIO;
goto not_jbd;
}
was_modified = jh->b_modified;
jh->b_modified = 0;
if (jh->b_transaction == handle->h_transaction) {
J_ASSERT_JH(jh, !jh->b_frozen_data);
clear_buffer_dirty(bh);
clear_buffer_jbddirty(bh);
JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
if (was_modified)
drop_reserve = 1;
if (jh->b_cp_transaction) {
__jbd2_journal_temp_unlink_buffer(jh);
__jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
} else {
__jbd2_journal_unfile_buffer(jh);
if (!buffer_jbd(bh)) {
spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh);
__bforget(bh);
goto drop;
}
}
} else if (jh->b_transaction) {
J_ASSERT_JH(jh, (jh->b_transaction ==
journal->j_committing_transaction));
JBUFFER_TRACE(jh, "belongs to older transaction");
if (jh->b_next_transaction) {
J_ASSERT(jh->b_next_transaction == transaction);
jh->b_next_transaction = NULL;
if (was_modified)
drop_reserve = 1;
}
}
not_jbd:
spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh);
__brelse(bh);
drop:
if (drop_reserve) {
handle->h_buffer_credits++;
}
return err;
}
