From 24bcc89c7e7c64982e6192b4952a0a92379fc341 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 13 Mar 2012 15:41:04 -0400 Subject: [PATCH] jbd2: split updating of journal superblock and marking journal empty There are three case of updating journal superblock. In the first case, we want to mark journal as empty (setting s_sequence to 0), in the second case we want to update log tail, in the third case we want to update s_errno. Split these cases into separate functions. It makes the code slightly more straightforward and later patches will make the distinction even more important. Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" --- fs/jbd2/checkpoint.c | 2 +- fs/jbd2/commit.c | 2 +- fs/jbd2/journal.c | 163 +++++++++++++++++++++--------------- include/linux/jbd2.h | 2 +- include/trace/events/jbd2.h | 12 +-- 5 files changed, 102 insertions(+), 79 deletions(-) diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 253e91890e71..19dcd0b86bca 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -550,7 +550,7 @@ int jbd2_cleanup_journal_tail(journal_t *journal) (journal->j_flags & JBD2_BARRIER)) blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); if (!(journal->j_flags & JBD2_ABORT)) - jbd2_journal_update_superblock(journal, 1); + jbd2_journal_update_sb_log_tail(journal); return 0; } diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 8adc5d460f56..19371a8a9015 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -340,7 +340,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) /* Do we need to erase the effects of a prior jbd2_journal_flush? */ if (journal->j_flags & JBD2_FLUSHED) { jbd_debug(3, "super block updated\n"); - jbd2_journal_update_superblock(journal, 1); + jbd2_journal_update_sb_log_tail(journal); } else { jbd_debug(3, "superblock not updated\n"); } diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index cfb36d99f7a4..6e75fbd75bad 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -1110,40 +1110,30 @@ static int journal_reset(journal_t *journal) journal->j_max_transaction_buffers = journal->j_maxlen / 4; - /* Add the dynamic fields and write it to disk. */ - jbd2_journal_update_superblock(journal, 1); - return jbd2_journal_start_thread(journal); -} - -/** - * void jbd2_journal_update_superblock() - Update journal sb on disk. - * @journal: The journal to update. - * @wait: Set to '0' if you don't want to wait for IO completion. - * - * Update a journal's dynamic superblock fields and write it to disk, - * optionally waiting for the IO to complete. - */ -void jbd2_journal_update_superblock(journal_t *journal, int wait) -{ - journal_superblock_t *sb = journal->j_superblock; - struct buffer_head *bh = journal->j_sb_buffer; - /* * As a special case, if the on-disk copy is already marked as needing - * no recovery (s_start == 0) and there are no outstanding transactions - * in the filesystem, then we can safely defer the superblock update - * until the next commit by setting JBD2_FLUSHED. This avoids + * no recovery (s_start == 0), then we can safely defer the superblock + * update until the next commit by setting JBD2_FLUSHED. This avoids * attempting a write to a potential-readonly device. */ - if (sb->s_start == 0 && journal->j_tail_sequence == - journal->j_transaction_sequence) { + if (sb->s_start == 0) { jbd_debug(1, "JBD2: Skipping superblock update on recovered sb " "(start %ld, seq %d, errno %d)\n", journal->j_tail, journal->j_tail_sequence, journal->j_errno); - goto out; + journal->j_flags |= JBD2_FLUSHED; + } else { + /* Add the dynamic fields and write it to disk. */ + jbd2_journal_update_sb_log_tail(journal); } + return jbd2_journal_start_thread(journal); +} +static void jbd2_write_superblock(journal_t *journal) +{ + struct buffer_head *bh = journal->j_sb_buffer; + + trace_jbd2_write_superblock(journal); if (buffer_write_io_error(bh)) { /* * Oh, dear. A previous attempt to write the journal @@ -1160,49 +1150,98 @@ void jbd2_journal_update_superblock(journal_t *journal, int wait) set_buffer_uptodate(bh); } + BUFFER_TRACE(bh, "marking dirty"); + mark_buffer_dirty(bh); + sync_dirty_buffer(bh); + if (buffer_write_io_error(bh)) { + printk(KERN_ERR "JBD2: I/O error detected " + "when updating journal superblock for %s.\n", + journal->j_devname); + clear_buffer_write_io_error(bh); + set_buffer_uptodate(bh); + } +} + +/** + * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk. + * @journal: The journal to update. + * + * Update a journal's superblock information about log tail and write it to + * disk, waiting for the IO to complete. + */ +void jbd2_journal_update_sb_log_tail(journal_t *journal) +{ + journal_superblock_t *sb = journal->j_superblock; + read_lock(&journal->j_state_lock); - jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d, errno %d)\n", - journal->j_tail, journal->j_tail_sequence, journal->j_errno); + jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d)\n", + journal->j_tail, journal->j_tail_sequence); sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); sb->s_start = cpu_to_be32(journal->j_tail); - sb->s_errno = cpu_to_be32(journal->j_errno); read_unlock(&journal->j_state_lock); - BUFFER_TRACE(bh, "marking dirty"); - mark_buffer_dirty(bh); - if (wait) { - sync_dirty_buffer(bh); - if (buffer_write_io_error(bh)) { - printk(KERN_ERR "JBD2: I/O error detected " - "when updating journal superblock for %s.\n", - journal->j_devname); - clear_buffer_write_io_error(bh); - set_buffer_uptodate(bh); - } - } else - write_dirty_buffer(bh, WRITE); + jbd2_write_superblock(journal); - trace_jbd2_update_superblock_end(journal, wait); + /* Log is no longer empty */ + write_lock(&journal->j_state_lock); + WARN_ON(!sb->s_sequence); + journal->j_flags &= ~JBD2_FLUSHED; + write_unlock(&journal->j_state_lock); +} -out: - /* If we have just flushed the log (by marking s_start==0), then - * any future commit will have to be careful to update the - * superblock again to re-record the true start of the log. */ +/** + * jbd2_mark_journal_empty() - Mark on disk journal as empty. + * @journal: The journal to update. + * + * Update a journal's dynamic superblock fields to show that journal is empty. + * Write updated superblock to disk waiting for IO to complete. + */ +static void jbd2_mark_journal_empty(journal_t *journal) +{ + journal_superblock_t *sb = journal->j_superblock; + + read_lock(&journal->j_state_lock); + jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n", + journal->j_tail_sequence); + + sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); + sb->s_start = cpu_to_be32(0); + read_unlock(&journal->j_state_lock); + + jbd2_write_superblock(journal); + /* Log is no longer empty */ write_lock(&journal->j_state_lock); - if (sb->s_start) - journal->j_flags &= ~JBD2_FLUSHED; - else - journal->j_flags |= JBD2_FLUSHED; + journal->j_flags |= JBD2_FLUSHED; write_unlock(&journal->j_state_lock); } + +/** + * jbd2_journal_update_sb_errno() - Update error in the journal. + * @journal: The journal to update. + * + * Update a journal's errno. Write updated superblock to disk waiting for IO + * to complete. + */ +static void jbd2_journal_update_sb_errno(journal_t *journal) +{ + journal_superblock_t *sb = journal->j_superblock; + + read_lock(&journal->j_state_lock); + jbd_debug(1, "JBD2: updating superblock error (errno %d)\n", + journal->j_errno); + sb->s_errno = cpu_to_be32(journal->j_errno); + read_unlock(&journal->j_state_lock); + + jbd2_write_superblock(journal); +} + /* * Read the superblock for a given journal, performing initial * validation of the format. */ - static int journal_get_superblock(journal_t *journal) { struct buffer_head *bh; @@ -1395,15 +1434,10 @@ int jbd2_journal_destroy(journal_t *journal) spin_unlock(&journal->j_list_lock); if (journal->j_sb_buffer) { - if (!is_journal_aborted(journal)) { - /* We can now mark the journal as empty. */ - journal->j_tail = 0; - journal->j_tail_sequence = - ++journal->j_transaction_sequence; - jbd2_journal_update_superblock(journal, 1); - } else { + if (!is_journal_aborted(journal)) + jbd2_mark_journal_empty(journal); + else err = -EIO; - } brelse(journal->j_sb_buffer); } @@ -1562,7 +1596,6 @@ int jbd2_journal_flush(journal_t *journal) { int err = 0; transaction_t *transaction = NULL; - unsigned long old_tail; write_lock(&journal->j_state_lock); @@ -1604,14 +1637,8 @@ int jbd2_journal_flush(journal_t *journal) * the magic code for a fully-recovered superblock. Any future * commits of data to the journal will restore the current * s_start value. */ + jbd2_mark_journal_empty(journal); write_lock(&journal->j_state_lock); - old_tail = journal->j_tail; - journal->j_tail = 0; - write_unlock(&journal->j_state_lock); - jbd2_journal_update_superblock(journal, 1); - write_lock(&journal->j_state_lock); - journal->j_tail = old_tail; - J_ASSERT(!journal->j_running_transaction); J_ASSERT(!journal->j_committing_transaction); J_ASSERT(!journal->j_checkpoint_transactions); @@ -1652,7 +1679,7 @@ int jbd2_journal_wipe(journal_t *journal, int write) err = jbd2_journal_skip_recovery(journal); if (write) - jbd2_journal_update_superblock(journal, 1); + jbd2_mark_journal_empty(journal); no_recovery: return err; @@ -1702,7 +1729,7 @@ static void __journal_abort_soft (journal_t *journal, int errno) __jbd2_journal_abort_hard(journal); if (errno) - jbd2_journal_update_superblock(journal, 1); + jbd2_journal_update_sb_errno(journal); } /** diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 46eef77e6ab8..5f05c77438e5 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1087,7 +1087,7 @@ extern int jbd2_journal_destroy (journal_t *); extern int jbd2_journal_recover (journal_t *journal); extern int jbd2_journal_wipe (journal_t *, int); extern int jbd2_journal_skip_recovery (journal_t *); -extern void jbd2_journal_update_superblock (journal_t *, int); +extern void jbd2_journal_update_sb_log_tail (journal_t *); extern void __jbd2_journal_abort_hard (journal_t *); extern void jbd2_journal_abort (journal_t *, int); extern int jbd2_journal_errno (journal_t *); diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h index ae59bc207d70..e05a362bf3f1 100644 --- a/include/trace/events/jbd2.h +++ b/include/trace/events/jbd2.h @@ -236,25 +236,21 @@ TRACE_EVENT(jbd2_cleanup_journal_tail, __entry->block_nr, __entry->freed) ); -TRACE_EVENT(jbd2_update_superblock_end, +TRACE_EVENT(jbd2_write_superblock, - TP_PROTO(journal_t *journal, int wait), + TP_PROTO(journal_t *journal), - TP_ARGS(journal, wait), + TP_ARGS(journal), TP_STRUCT__entry( __field( dev_t, dev ) - __field( int, wait ) ), TP_fast_assign( __entry->dev = journal->j_fs_dev->bd_dev; - __entry->wait = wait; ), - TP_printk("dev %d,%d wait %d", - MAJOR(__entry->dev), MINOR(__entry->dev), - __entry->wait) + TP_printk("dev %d,%d", MAJOR(__entry->dev), MINOR(__entry->dev)) ); #endif /* _TRACE_JBD2_H */ -- 2.20.1