diff options
Diffstat (limited to 'fs/jbd/commit.c')
| -rw-r--r-- | fs/jbd/commit.c | 183 |
1 files changed, 125 insertions, 58 deletions
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c index 34a4861c14b8..bb217dcb41af 100644 --- a/fs/jbd/commit.c +++ b/fs/jbd/commit.c @@ -20,6 +20,8 @@ #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/bio.h> +#include <linux/blkdev.h> +#include <trace/events/jbd.h> /* * Default IO end handler for temporary BJ_IO buffer_heads. @@ -84,7 +86,12 @@ nope: static void release_data_buffer(struct buffer_head *bh) { if (buffer_freed(bh)) { + WARN_ON_ONCE(buffer_dirty(bh)); clear_buffer_freed(bh); + clear_buffer_mapped(bh); + clear_buffer_new(bh); + clear_buffer_req(bh); + bh->b_bdev = NULL; release_buffer_page(bh); } else put_bh(bh); @@ -155,8 +162,17 @@ static void journal_do_submit_data(struct buffer_head **wbuf, int bufs, for (i = 0; i < bufs; i++) { wbuf[i]->b_end_io = end_buffer_write_sync; - /* We use-up our safety reference in submit_bh() */ - submit_bh(write_op, wbuf[i]); + /* + * Here we write back pagecache data that may be mmaped. Since + * we cannot afford to clean the page and set PageWriteback + * here due to lock ordering (page lock ranks above transaction + * start), the data can change while IO is in flight. Tell the + * block layer it should bounce the bio pages if stable data + * during write is required. + * + * We use up our safety reference in submit_bh(). + */ + _submit_bh(write_op, wbuf[i], 1 << BIO_SNAP_STABLE); } } @@ -203,6 +219,8 @@ write_out_data: if (!trylock_buffer(bh)) { BUFFER_TRACE(bh, "needs blocking lock"); spin_unlock(&journal->j_list_lock); + trace_jbd_do_submit_data(journal, + commit_transaction); /* Write out all data to prevent deadlocks */ journal_do_submit_data(wbuf, bufs, write_op); bufs = 0; @@ -235,6 +253,8 @@ write_out_data: jbd_unlock_bh_state(bh); if (bufs == journal->j_wbufsize) { spin_unlock(&journal->j_list_lock); + trace_jbd_do_submit_data(journal, + commit_transaction); journal_do_submit_data(wbuf, bufs, write_op); bufs = 0; goto write_out_data; @@ -252,10 +272,6 @@ write_out_data: jbd_unlock_bh_state(bh); if (locked) unlock_buffer(bh); - journal_remove_journal_head(bh); - /* One for our safety reference, other for - * journal_remove_journal_head() */ - put_bh(bh); release_data_buffer(bh); } @@ -265,6 +281,7 @@ write_out_data: } } spin_unlock(&journal->j_list_lock); + trace_jbd_do_submit_data(journal, commit_transaction); journal_do_submit_data(wbuf, bufs, write_op); return err; @@ -294,23 +311,27 @@ void journal_commit_transaction(journal_t *journal) int first_tag = 0; int tag_flag; int i; - int write_op = WRITE_SYNC; + struct blk_plug plug; + int write_op = WRITE; /* * First job: lock down the current transaction and wait for * all outstanding updates to complete. */ -#ifdef COMMIT_STATS - spin_lock(&journal->j_list_lock); - summarise_journal_usage(journal); - spin_unlock(&journal->j_list_lock); -#endif - /* Do we need to erase the effects of a prior journal_flush? */ if (journal->j_flags & JFS_FLUSHED) { jbd_debug(3, "super block updated\n"); - journal_update_superblock(journal, 1); + mutex_lock(&journal->j_checkpoint_mutex); + /* + * We hold j_checkpoint_mutex so tail cannot change under us. + * We don't need any special data guarantees for writing sb + * since journal is empty and it is ok for write to be + * flushed only with transaction commit. + */ + journal_update_sb_log_tail(journal, journal->j_tail_sequence, + journal->j_tail, WRITE_SYNC); + mutex_unlock(&journal->j_checkpoint_mutex); } else { jbd_debug(3, "superblock not updated\n"); } @@ -319,21 +340,16 @@ void journal_commit_transaction(journal_t *journal) J_ASSERT(journal->j_committing_transaction == NULL); commit_transaction = journal->j_running_transaction; - J_ASSERT(commit_transaction->t_state == T_RUNNING); + trace_jbd_start_commit(journal, commit_transaction); jbd_debug(1, "JBD: starting commit of transaction %d\n", commit_transaction->t_tid); spin_lock(&journal->j_state_lock); + J_ASSERT(commit_transaction->t_state == T_RUNNING); commit_transaction->t_state = T_LOCKED; - /* - * Use plugged writes here, since we want to submit several before - * we unplug the device. We don't do explicit unplugging in here, - * instead we rely on sync_buffer() doing the unplug for us. - */ - if (commit_transaction->t_synchronous_commit) - write_op = WRITE_SYNC_PLUG; + trace_jbd_commit_locking(journal, commit_transaction); spin_lock(&commit_transaction->t_handle_lock); while (commit_transaction->t_updates) { DEFINE_WAIT(wait); @@ -368,7 +384,7 @@ void journal_commit_transaction(journal_t *journal) * we do not require it to remember exactly which old buffers it * has reserved. This is consistent with the existing behaviour * that multiple journal_get_write_access() calls to the same - * buffer are perfectly permissable. + * buffer are perfectly permissible. */ while (commit_transaction->t_reserved_list) { jh = commit_transaction->t_reserved_list; @@ -400,10 +416,17 @@ void journal_commit_transaction(journal_t *journal) jbd_debug (3, "JBD: commit phase 1\n"); /* + * Clear revoked flag to reflect there is no revoked buffers + * in the next transaction which is going to be started. + */ + journal_clear_buffer_revoked_flags(journal); + + /* * Switch to a new revoke table. */ journal_switch_revoke_table(journal); + trace_jbd_commit_flushing(journal, commit_transaction); commit_transaction->t_state = T_FLUSH; journal->j_committing_transaction = commit_transaction; journal->j_running_transaction = NULL; @@ -414,12 +437,17 @@ void journal_commit_transaction(journal_t *journal) jbd_debug (3, "JBD: commit phase 2\n"); + if (tid_geq(journal->j_commit_waited, commit_transaction->t_tid)) + write_op = WRITE_SYNC; + /* * Now start flushing things to disk, in the order they appear * on the transaction lists. Data blocks go first. */ + blk_start_plug(&plug); err = journal_submit_data_buffers(journal, commit_transaction, write_op); + blk_finish_plug(&plug); /* * Wait for all previously submitted IO to complete. @@ -456,14 +484,9 @@ void journal_commit_transaction(journal_t *journal) } if (buffer_jbd(bh) && bh2jh(bh) == jh && jh->b_transaction == commit_transaction && - jh->b_jlist == BJ_Locked) { + jh->b_jlist == BJ_Locked) __journal_unfile_buffer(jh); - jbd_unlock_bh_state(bh); - journal_remove_journal_head(bh); - put_bh(bh); - } else { - jbd_unlock_bh_state(bh); - } + jbd_unlock_bh_state(bh); release_data_buffer(bh); cond_resched_lock(&journal->j_list_lock); } @@ -480,6 +503,8 @@ void journal_commit_transaction(journal_t *journal) err = 0; } + blk_start_plug(&plug); + journal_write_revoke_records(journal, commit_transaction, write_op); /* @@ -501,6 +526,7 @@ void journal_commit_transaction(journal_t *journal) commit_transaction->t_state = T_COMMIT; spin_unlock(&journal->j_state_lock); + trace_jbd_commit_logging(journal, commit_transaction); J_ASSERT(commit_transaction->t_nr_buffers <= commit_transaction->t_outstanding_credits); @@ -650,7 +676,17 @@ start_journal_io: clear_buffer_dirty(bh); set_buffer_uptodate(bh); bh->b_end_io = journal_end_buffer_io_sync; - submit_bh(write_op, bh); + /* + * In data=journal mode, here we can end up + * writing pagecache data that might be + * mmapped. Since we can't afford to clean the + * page and set PageWriteback (see the comment + * near the other use of _submit_bh()), the + * data can change while the write is in + * flight. Tell the block layer to bounce the + * bio pages if stable pages are required. + */ + _submit_bh(write_op, bh, 1 << BIO_SNAP_STABLE); } cond_resched(); @@ -661,6 +697,8 @@ start_journal_io: } } + blk_finish_plug(&plug); + /* Lo and behold: we have just managed to send a transaction to the log. Before we can commit it, wait for the IO so far to complete. Control buffers being written are on the @@ -722,8 +760,13 @@ wait_for_iobuf: required. */ JBUFFER_TRACE(jh, "file as BJ_Forget"); journal_file_buffer(jh, commit_transaction, BJ_Forget); - /* Wake up any transactions which were waiting for this - IO to complete */ + /* + * Wake up any transactions which were waiting for this + * IO to complete. The barrier must be here so that changes + * by journal_file_buffer() take effect before wake_up_bit() + * does the waitqueue check. + */ + smp_mb(); wake_up_bit(&bh->b_state, BH_Unshadow); JBUFFER_TRACE(jh, "brelse shadowed buffer"); __brelse(bh); @@ -798,10 +841,16 @@ restart_loop: while (commit_transaction->t_forget) { transaction_t *cp_transaction; struct buffer_head *bh; + int try_to_free = 0; jh = commit_transaction->t_forget; spin_unlock(&journal->j_list_lock); bh = jh2bh(jh); + /* + * Get a reference so that bh cannot be freed before we are + * done with it. + */ + get_bh(bh); jbd_lock_bh_state(bh); J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || jh->b_transaction == journal->j_running_transaction); @@ -841,17 +890,35 @@ restart_loop: * there's no point in keeping a checkpoint record for * it. */ - /* 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 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) && !jh->b_next_transaction) { - clear_buffer_freed(bh); - clear_buffer_jbddirty(bh); + /* + * A buffer which has been freed while still being journaled by + * a previous transaction. + */ + if (buffer_freed(bh)) { + /* + * If the running transaction is the one containing + * "add to orphan" operation (b_next_transaction != + * NULL), we have to wait for that transaction to + * commit before we can really get rid of the buffer. + * So just clear b_modified to not confuse transaction + * credit accounting and refile the buffer to + * BJ_Forget of the running transaction. If the just + * committed transaction contains "add to orphan" + * operation, we can completely invalidate the buffer + * now. We are rather throughout in that since the + * buffer may be still accessible when blocksize < + * pagesize and it is attached to the last partial + * page. + */ + jh->b_modified = 0; + if (!jh->b_next_transaction) { + clear_buffer_freed(bh); + clear_buffer_jbddirty(bh); + clear_buffer_mapped(bh); + clear_buffer_new(bh); + clear_buffer_req(bh); + bh->b_bdev = NULL; + } } if (buffer_jbddirty(bh)) { @@ -859,28 +926,27 @@ restart_loop: __journal_insert_checkpoint(jh, commit_transaction); if (is_journal_aborted(journal)) clear_buffer_jbddirty(bh); - JBUFFER_TRACE(jh, "refile for checkpoint writeback"); - __journal_refile_buffer(jh); - jbd_unlock_bh_state(bh); } else { J_ASSERT_BH(bh, !buffer_dirty(bh)); - /* The buffer on BJ_Forget list and not jbddirty means + /* + * The buffer on BJ_Forget list and not jbddirty means * it has been freed by this transaction and hence it * could not have been reallocated until this * transaction has committed. *BUT* it could be * reallocated once we have written all the data to * disk and before we process the buffer on BJ_Forget - * list. */ - JBUFFER_TRACE(jh, "refile or unfile freed buffer"); - __journal_refile_buffer(jh); - if (!jh->b_transaction) { - jbd_unlock_bh_state(bh); - /* needs a brelse */ - journal_remove_journal_head(bh); - release_buffer_page(bh); - } else - jbd_unlock_bh_state(bh); + * list. + */ + if (!jh->b_next_transaction) + try_to_free = 1; } + JBUFFER_TRACE(jh, "refile or unfile freed buffer"); + __journal_refile_buffer(jh); + jbd_unlock_bh_state(bh); + if (try_to_free) + release_buffer_page(bh); + else + __brelse(bh); cond_resched_lock(&journal->j_list_lock); } spin_unlock(&journal->j_list_lock); @@ -947,6 +1013,7 @@ restart_loop: } spin_unlock(&journal->j_list_lock); + trace_jbd_end_commit(journal, commit_transaction); jbd_debug(1, "JBD: commit %d complete, head %d\n", journal->j_commit_sequence, journal->j_tail_sequence); |