From ff780b91efe901b8eecd8114785abae5341820ad Mon Sep 17 00:00:00 2001 From: Harshad Shirwadkar Date: Thu, 15 Oct 2020 13:37:56 -0700 Subject: [PATCH] jbd2: add fast commit machinery This functions adds necessary APIs needed in JBD2 layer for fast commits. Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201015203802.3597742-5-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o --- fs/ext4/fast_commit.c | 8 +++ fs/jbd2/commit.c | 44 ++++++++++++ fs/jbd2/journal.c | 190 +++++++++++++++++++++++++++++++++++++++++++++++++- include/linux/jbd2.h | 27 +++++++ 4 files changed, 268 insertions(+), 1 deletion(-) diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index 0dad8bd..f2d11b4 100644 --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -8,11 +8,19 @@ * Ext4 fast commits routines. */ #include "ext4_jbd2.h" +/* + * Fast commit cleanup routine. This is called after every fast commit and + * full commit. full is true if we are called after a full commit. + */ +static void ext4_fc_cleanup(journal_t *journal, int full) +{ +} void ext4_fc_init(struct super_block *sb, journal_t *journal) { if (!test_opt2(sb, JOURNAL_FAST_COMMIT)) return; + journal->j_fc_cleanup_callback = ext4_fc_cleanup; if (jbd2_fc_init(journal, EXT4_NUM_FC_BLKS)) { pr_warn("Error while enabling fast commits, turning off."); ext4_clear_feature_fast_commit(sb); diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 6252b4c..fa688e1 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -206,6 +206,30 @@ int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode) return generic_writepages(mapping, &wbc); } +/* Send all the data buffers related to an inode */ +int jbd2_submit_inode_data(struct jbd2_inode *jinode) +{ + + if (!jinode || !(jinode->i_flags & JI_WRITE_DATA)) + return 0; + + trace_jbd2_submit_inode_data(jinode->i_vfs_inode); + return jbd2_journal_submit_inode_data_buffers(jinode); + +} +EXPORT_SYMBOL(jbd2_submit_inode_data); + +int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode) +{ + if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) || + !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping) + return 0; + return filemap_fdatawait_range_keep_errors( + jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start, + jinode->i_dirty_end); +} +EXPORT_SYMBOL(jbd2_wait_inode_data); + /* * Submit all the data buffers of inode associated with the transaction to * disk. @@ -415,6 +439,20 @@ void jbd2_journal_commit_transaction(journal_t *journal) J_ASSERT(journal->j_running_transaction != NULL); J_ASSERT(journal->j_committing_transaction == NULL); + write_lock(&journal->j_state_lock); + journal->j_flags |= JBD2_FULL_COMMIT_ONGOING; + while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) { + DEFINE_WAIT(wait); + + prepare_to_wait(&journal->j_fc_wait, &wait, + TASK_UNINTERRUPTIBLE); + write_unlock(&journal->j_state_lock); + schedule(); + write_lock(&journal->j_state_lock); + finish_wait(&journal->j_fc_wait, &wait); + } + write_unlock(&journal->j_state_lock); + commit_transaction = journal->j_running_transaction; trace_jbd2_start_commit(journal, commit_transaction); @@ -422,6 +460,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) commit_transaction->t_tid); write_lock(&journal->j_state_lock); + journal->j_fc_off = 0; J_ASSERT(commit_transaction->t_state == T_RUNNING); commit_transaction->t_state = T_LOCKED; @@ -1121,12 +1160,16 @@ restart_loop: if (journal->j_commit_callback) journal->j_commit_callback(journal, commit_transaction); + if (journal->j_fc_cleanup_callback) + journal->j_fc_cleanup_callback(journal, 1); trace_jbd2_end_commit(journal, commit_transaction); jbd_debug(1, "JBD2: commit %d complete, head %d\n", journal->j_commit_sequence, journal->j_tail_sequence); write_lock(&journal->j_state_lock); + journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING; + journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING; spin_lock(&journal->j_list_lock); commit_transaction->t_state = T_FINISHED; /* Check if the transaction can be dropped now that we are finished */ @@ -1138,6 +1181,7 @@ restart_loop: spin_unlock(&journal->j_list_lock); write_unlock(&journal->j_state_lock); wake_up(&journal->j_wait_done_commit); + wake_up(&journal->j_fc_wait); /* * Calculate overall stats diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 4497bfb..0c7c42b 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -159,7 +159,9 @@ static void commit_timeout(struct timer_list *t) * * 1) COMMIT: Every so often we need to commit the current state of the * filesystem to disk. The journal thread is responsible for writing - * all of the metadata buffers to disk. + * all of the metadata buffers to disk. If a fast commit is ongoing + * journal thread waits until it's done and then continues from + * there on. * * 2) CHECKPOINT: We cannot reuse a used section of the log file until all * of the data in that part of the log has been rewritten elsewhere on @@ -716,6 +718,75 @@ int jbd2_log_wait_commit(journal_t *journal, tid_t tid) return err; } +/* + * Start a fast commit. If there's an ongoing fast or full commit wait for + * it to complete. Returns 0 if a new fast commit was started. Returns -EALREADY + * if a fast commit is not needed, either because there's an already a commit + * going on or this tid has already been committed. Returns -EINVAL if no jbd2 + * commit has yet been performed. + */ +int jbd2_fc_begin_commit(journal_t *journal, tid_t tid) +{ + /* + * Fast commits only allowed if at least one full commit has + * been processed. + */ + if (!journal->j_stats.ts_tid) + return -EINVAL; + + if (tid <= journal->j_commit_sequence) + return -EALREADY; + + write_lock(&journal->j_state_lock); + if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING || + (journal->j_flags & JBD2_FAST_COMMIT_ONGOING)) { + DEFINE_WAIT(wait); + + prepare_to_wait(&journal->j_fc_wait, &wait, + TASK_UNINTERRUPTIBLE); + write_unlock(&journal->j_state_lock); + schedule(); + finish_wait(&journal->j_fc_wait, &wait); + return -EALREADY; + } + journal->j_flags |= JBD2_FAST_COMMIT_ONGOING; + write_unlock(&journal->j_state_lock); + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_begin_commit); + +/* + * Stop a fast commit. If fallback is set, this function starts commit of + * TID tid before any other fast commit can start. + */ +static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback) +{ + if (journal->j_fc_cleanup_callback) + journal->j_fc_cleanup_callback(journal, 0); + write_lock(&journal->j_state_lock); + journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING; + if (fallback) + journal->j_flags |= JBD2_FULL_COMMIT_ONGOING; + write_unlock(&journal->j_state_lock); + wake_up(&journal->j_fc_wait); + if (fallback) + return jbd2_complete_transaction(journal, tid); + return 0; +} + +int jbd2_fc_end_commit(journal_t *journal) +{ + return __jbd2_fc_end_commit(journal, 0, 0); +} +EXPORT_SYMBOL(jbd2_fc_end_commit); + +int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid) +{ + return __jbd2_fc_end_commit(journal, tid, 1); +} +EXPORT_SYMBOL(jbd2_fc_end_commit_fallback); + /* Return 1 when transaction with given tid has already committed. */ int jbd2_transaction_committed(journal_t *journal, tid_t tid) { @@ -784,6 +855,110 @@ int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp) return jbd2_journal_bmap(journal, blocknr, retp); } +/* Map one fast commit buffer for use by the file system */ +int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out) +{ + unsigned long long pblock; + unsigned long blocknr; + int ret = 0; + struct buffer_head *bh; + int fc_off; + + *bh_out = NULL; + write_lock(&journal->j_state_lock); + + if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) { + fc_off = journal->j_fc_off; + blocknr = journal->j_fc_first + fc_off; + journal->j_fc_off++; + } else { + ret = -EINVAL; + } + write_unlock(&journal->j_state_lock); + + if (ret) + return ret; + + ret = jbd2_journal_bmap(journal, blocknr, &pblock); + if (ret) + return ret; + + bh = __getblk(journal->j_dev, pblock, journal->j_blocksize); + if (!bh) + return -ENOMEM; + + lock_buffer(bh); + + clear_buffer_uptodate(bh); + set_buffer_dirty(bh); + unlock_buffer(bh); + journal->j_fc_wbuf[fc_off] = bh; + + *bh_out = bh; + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_get_buf); + +/* + * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf + * for completion. + */ +int jbd2_fc_wait_bufs(journal_t *journal, int num_blks) +{ + struct buffer_head *bh; + int i, j_fc_off; + + read_lock(&journal->j_state_lock); + j_fc_off = journal->j_fc_off; + read_unlock(&journal->j_state_lock); + + /* + * Wait in reverse order to minimize chances of us being woken up before + * all IOs have completed + */ + for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) { + bh = journal->j_fc_wbuf[i]; + wait_on_buffer(bh); + put_bh(bh); + journal->j_fc_wbuf[i] = NULL; + if (unlikely(!buffer_uptodate(bh))) + return -EIO; + } + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_wait_bufs); + +/* + * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf + * for completion. + */ +int jbd2_fc_release_bufs(journal_t *journal) +{ + struct buffer_head *bh; + int i, j_fc_off; + + read_lock(&journal->j_state_lock); + j_fc_off = journal->j_fc_off; + read_unlock(&journal->j_state_lock); + + /* + * Wait in reverse order to minimize chances of us being woken up before + * all IOs have completed + */ + for (i = j_fc_off - 1; i >= 0; i--) { + bh = journal->j_fc_wbuf[i]; + if (!bh) + break; + put_bh(bh); + journal->j_fc_wbuf[i] = NULL; + } + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_release_bufs); + /* * Conversion of logical to physical block numbers for the journal * @@ -1142,6 +1317,7 @@ static journal_t *journal_init_common(struct block_device *bdev, init_waitqueue_head(&journal->j_wait_commit); init_waitqueue_head(&journal->j_wait_updates); init_waitqueue_head(&journal->j_wait_reserved); + init_waitqueue_head(&journal->j_fc_wait); mutex_init(&journal->j_abort_mutex); mutex_init(&journal->j_barrier); mutex_init(&journal->j_checkpoint_mutex); @@ -1495,6 +1671,7 @@ out: static void jbd2_mark_journal_empty(journal_t *journal, int write_op) { journal_superblock_t *sb = journal->j_superblock; + bool had_fast_commit = false; BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); lock_buffer(journal->j_sb_buffer); @@ -1508,9 +1685,20 @@ static void jbd2_mark_journal_empty(journal_t *journal, int write_op) sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); sb->s_start = cpu_to_be32(0); + if (jbd2_has_feature_fast_commit(journal)) { + /* + * When journal is clean, no need to commit fast commit flag and + * make file system incompatible with older kernels. + */ + jbd2_clear_feature_fast_commit(journal); + had_fast_commit = true; + } jbd2_write_superblock(journal, write_op); + if (had_fast_commit) + jbd2_set_feature_fast_commit(journal); + /* Log is no longer empty */ write_lock(&journal->j_state_lock); journal->j_flags |= JBD2_FLUSHED; diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 008629b..a009d9b 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -862,6 +862,13 @@ struct journal_s wait_queue_head_t j_wait_reserved; /** + * @j_fc_wait: + * + * Wait queue to wait for completion of async fast commits. + */ + wait_queue_head_t j_fc_wait; + + /** * @j_checkpoint_mutex: * * Semaphore for locking against concurrent checkpoints. @@ -1232,6 +1239,15 @@ struct journal_s */ struct lockdep_map j_trans_commit_map; #endif + + /** + * @j_fc_cleanup_callback: + * + * Clean-up after fast commit or full commit. JBD2 calls this function + * after every commit operation. + */ + void (*j_fc_cleanup_callback)(struct journal_s *journal, int); + }; #define jbd2_might_wait_for_commit(j) \ @@ -1316,6 +1332,8 @@ JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit, FAST_COMMIT) #define JBD2_ABORT_ON_SYNCDATA_ERR 0x040 /* Abort the journal on file * data write error in ordered * mode */ +#define JBD2_FAST_COMMIT_ONGOING 0x100 /* Fast commit is ongoing */ +#define JBD2_FULL_COMMIT_ONGOING 0x200 /* Full commit is ongoing */ /* * Function declarations for the journaling transaction and buffer @@ -1574,6 +1592,15 @@ extern int jbd2_cleanup_journal_tail(journal_t *); /* Fast commit related APIs */ int jbd2_fc_init(journal_t *journal, int num_fc_blks); +int jbd2_fc_begin_commit(journal_t *journal, tid_t tid); +int jbd2_fc_end_commit(journal_t *journal); +int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid); +int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out); +int jbd2_submit_inode_data(struct jbd2_inode *jinode); +int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode); +int jbd2_fc_wait_bufs(journal_t *journal, int num_blks); +int jbd2_fc_release_bufs(journal_t *journal); + /* * is_journal_abort * -- 2.7.4