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jbd2: Factor out common parts of stopping and restarting a handle 

jbd2__journal_restart() has quite some code that is common with
jbd2_journal_stop(). Factor this functionality into stop_this_handle()
helper and use it from both functions. Note that this also drops
t_handle_lock protection from jbd2__journal_restart() as
jbd2_journal_stop() does the same thing without it.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-17-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Jan Kara 2019-11-05 17:44:23 +01:00 committed by Theodore Ts'o
parent 5559b2d81b
commit ec8b6f600e
1 changed files with 47 additions and 53 deletions
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100
fs/jbd2/transaction.c
View File

@ -512,12 +512,17 @@ handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
}
EXPORT_SYMBOL(jbd2_journal_start);
void jbd2_journal_free_reserved(handle_t *handle)
static void __jbd2_journal_unreserve_handle(handle_t *handle)
{
journal_t *journal = handle->h_journal;
WARN_ON(!handle->h_reserved);
sub_reserved_credits(journal, handle->h_buffer_credits);
}
void jbd2_journal_free_reserved(handle_t *handle)
{
__jbd2_journal_unreserve_handle(handle);
jbd2_free_handle(handle);
}
EXPORT_SYMBOL(jbd2_journal_free_reserved);
@ -655,6 +660,28 @@ error_out:
return result;
}
static void stop_this_handle(handle_t *handle)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
J_ASSERT(journal_current_handle() == handle);
J_ASSERT(atomic_read(&transaction->t_updates) > 0);
current->journal_info = NULL;
atomic_sub(handle->h_buffer_credits,
&transaction->t_outstanding_credits);
if (handle->h_rsv_handle)
__jbd2_journal_unreserve_handle(handle->h_rsv_handle);
if (atomic_dec_and_test(&transaction->t_updates))
wake_up(&journal->j_wait_updates);
rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
/*
* Scope of the GFP_NOFS context is over here and so we can restore the
* original alloc context.
*/
memalloc_nofs_restore(handle->saved_alloc_context);
}
/**
* int jbd2_journal_restart() - restart a handle .
@ -677,52 +704,34 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
transaction_t *transaction = handle->h_transaction;
journal_t *journal;
tid_t tid;
int need_to_start, ret;
int need_to_start;
/* If we've had an abort of any type, don't even think about
* actually doing the restart! */
if (is_handle_aborted(handle))
return 0;
journal = transaction->t_journal;
tid = transaction->t_tid;
/*
* First unlink the handle from its current transaction, and start the
* commit on that.
*/
J_ASSERT(atomic_read(&transaction->t_updates) > 0);
J_ASSERT(journal_current_handle() == handle);
read_lock(&journal->j_state_lock);
spin_lock(&transaction->t_handle_lock);
atomic_sub(handle->h_buffer_credits,
&transaction->t_outstanding_credits);
if (handle->h_rsv_handle) {
sub_reserved_credits(journal,
handle->h_rsv_handle->h_buffer_credits);
}
if (atomic_dec_and_test(&transaction->t_updates))
wake_up(&journal->j_wait_updates);
tid = transaction->t_tid;
spin_unlock(&transaction->t_handle_lock);
handle->h_transaction = NULL;
current->journal_info = NULL;
jbd_debug(2, "restarting handle %p\n", handle);
stop_this_handle(handle);
handle->h_transaction = NULL;
/*
* TODO: If we use READ_ONCE / WRITE_ONCE for j_commit_request we can
* get rid of pointless j_state_lock traffic like this.
*/
read_lock(&journal->j_state_lock);
need_to_start = !tid_geq(journal->j_commit_request, tid);
read_unlock(&journal->j_state_lock);
if (need_to_start)
jbd2_log_start_commit(journal, tid);
rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
handle->h_buffer_credits = nblocks;
/*
* Restore the original nofs context because the journal restart
* is basically the same thing as journal stop and start.
* start_this_handle will start a new nofs context.
*/
memalloc_nofs_restore(handle->saved_alloc_context);
ret = start_this_handle(journal, handle, gfp_mask);
return ret;
return start_this_handle(journal, handle, gfp_mask);
}
EXPORT_SYMBOL(jbd2__journal_restart);
@ -1718,16 +1727,12 @@ int jbd2_journal_stop(handle_t *handle)
* Handle is already detached from the transaction so there is
* nothing to do other than free the handle.
*/
if (handle->h_rsv_handle)
jbd2_free_handle(handle->h_rsv_handle);
memalloc_nofs_restore(handle->saved_alloc_context);
goto free_and_exit;
}
journal = transaction->t_journal;
tid = transaction->t_tid;
J_ASSERT(journal_current_handle() == handle);
J_ASSERT(atomic_read(&transaction->t_updates) > 0);
if (is_handle_aborted(handle))
err = -EIO;
@ -1797,9 +1802,6 @@ int jbd2_journal_stop(handle_t *handle)
if (handle->h_sync)
transaction->t_synchronous_commit = 1;
current->journal_info = NULL;
atomic_sub(handle->h_buffer_credits,
&transaction->t_outstanding_credits);
/*
* If the handle is marked SYNC, we need to set another commit
@ -1826,27 +1828,19 @@ int jbd2_journal_stop(handle_t *handle)
}
/*
* Once we drop t_updates, if it goes to zero the transaction
* could start committing on us and eventually disappear. So
* once we do this, we must not dereference transaction
* pointer again.
* Once stop_this_handle() drops t_updates, the transaction could start
* committing on us and eventually disappear. So we must not
* dereference transaction pointer again after calling
* stop_this_handle().
*/
if (atomic_dec_and_test(&transaction->t_updates))
wake_up(&journal->j_wait_updates);
rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
stop_this_handle(handle);
if (wait_for_commit)
err = jbd2_log_wait_commit(journal, tid);
if (handle->h_rsv_handle)
jbd2_journal_free_reserved(handle->h_rsv_handle);
free_and_exit:
/*
* Scope of the GFP_NOFS context is over here and so we can restore the
* original alloc context.
*/
memalloc_nofs_restore(handle->saved_alloc_context);
if (handle->h_rsv_handle)
jbd2_free_handle(handle->h_rsv_handle);
jbd2_free_handle(handle);
return err;
}