From 325020477a51ffa849418b3e38189fd266f2ae20 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Tue, 29 Jun 2010 14:42:13 +0900 Subject: [PATCH] nilfs2: do not update log cursor for small change Super blocks of nilfs are periodically overwritten in order to record the recent log position. This shortens recovery time after unclean unmount, but the current implementation performs the update even for a few blocks of change. If the filesystem gets small changes slowly and continually, super blocks may be updated excessively. This moderates the issue by skipping update of log cursor if it does not cross a segment boundary. Signed-off-by: Ryusuke Konishi --- fs/nilfs2/segment.c | 1 - fs/nilfs2/the_nilfs.c | 11 +++++++++++ fs/nilfs2/the_nilfs.h | 2 ++ 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c index 04e04854a311..9fd051a33c4f 100644 --- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -1951,7 +1951,6 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci) if (update_sr) { nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start, segbuf->sb_sum.seg_seq, nilfs->ns_cno++); - set_nilfs_sb_dirty(nilfs); clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags); clear_bit(NILFS_SC_DIRTY, &sci->sc_flags); diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 88c8976c55a9..f2efc8c5be7f 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -47,6 +47,16 @@ void nilfs_set_last_segment(struct the_nilfs *nilfs, nilfs->ns_last_pseg = start_blocknr; nilfs->ns_last_seq = seq; nilfs->ns_last_cno = cno; + + if (!nilfs_sb_dirty(nilfs)) { + if (nilfs->ns_prev_seq == nilfs->ns_last_seq) + goto stay_cursor; + + set_nilfs_sb_dirty(nilfs); + } + nilfs->ns_prev_seq = nilfs->ns_last_seq; + + stay_cursor: spin_unlock(&nilfs->ns_last_segment_lock); } @@ -267,6 +277,7 @@ static int nilfs_store_log_cursor(struct the_nilfs *nilfs, nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno); nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq); + nilfs->ns_prev_seq = nilfs->ns_last_seq; nilfs->ns_seg_seq = nilfs->ns_last_seq; nilfs->ns_segnum = nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg); diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index 32b4983b7458..f785a7b0ab99 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -74,6 +74,7 @@ enum { * @ns_last_seq: sequence value of the latest segment * @ns_last_cno: checkpoint number of the latest segment * @ns_prot_seq: least sequence number of segments which must not be reclaimed + * @ns_prev_seq: base sequence number used to decide if advance log cursor * @ns_segctor_sem: segment constructor semaphore * @ns_dat: DAT file inode * @ns_cpfile: checkpoint file inode @@ -151,6 +152,7 @@ struct the_nilfs { u64 ns_last_seq; __u64 ns_last_cno; u64 ns_prot_seq; + u64 ns_prev_seq; struct rw_semaphore ns_segctor_sem; -- 2.20.1