From 34cc1781c2ae921107e89f6633cfab7436e355ba Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Fri, 9 Mar 2012 10:45:56 +0000 Subject: [PATCH] GFS2: Clean up log flush header writing We already send both a pre and post flush to the block device when writing a journal header. There is no need to wait for the previous I/O specifically when we do this, unless we've turned "barriers" off. As a side effect, this also cleans up the code path for flushing the journal and makes it more readable. Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 131 +++++++++++++++++++++++++------------------------- 1 file changed, 66 insertions(+), 65 deletions(-) diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 2b9f0d9b1b28..4752eadc7f6e 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -491,66 +491,8 @@ static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail) sdp->sd_log_tail = new_tail; } -/** - * log_write_header - Get and initialize a journal header buffer - * @sdp: The GFS2 superblock - * - * Returns: the initialized log buffer descriptor - */ -static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull) -{ - u64 blkno = gfs2_log_bmap(sdp, sdp->sd_log_flush_head); - struct buffer_head *bh; - struct gfs2_log_header *lh; - unsigned int tail; - u32 hash; - - bh = sb_getblk(sdp->sd_vfs, blkno); - lock_buffer(bh); - memset(bh->b_data, 0, bh->b_size); - set_buffer_uptodate(bh); - clear_buffer_dirty(bh); - - gfs2_ail1_empty(sdp); - tail = current_tail(sdp); - - lh = (struct gfs2_log_header *)bh->b_data; - memset(lh, 0, sizeof(struct gfs2_log_header)); - lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC); - lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH); - lh->lh_header.__pad0 = cpu_to_be64(0); - lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH); - lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid); - lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++); - lh->lh_flags = cpu_to_be32(flags); - lh->lh_tail = cpu_to_be32(tail); - lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head); - hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header)); - lh->lh_hash = cpu_to_be32(hash); - - bh->b_end_io = end_buffer_write_sync; - get_bh(bh); - if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) - submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh); - else - submit_bh(WRITE_FLUSH_FUA | REQ_META, bh); - wait_on_buffer(bh); - - if (!buffer_uptodate(bh)) - gfs2_io_error_bh(sdp, bh); - brelse(bh); - - if (sdp->sd_log_tail != tail) - log_pull_tail(sdp, tail); - else - gfs2_assert_withdraw(sdp, !pull); - - sdp->sd_log_idle = (tail == sdp->sd_log_flush_head); - gfs2_log_incr_head(sdp); -} - -static void log_flush_commit(struct gfs2_sbd *sdp) +static void log_flush_wait(struct gfs2_sbd *sdp) { DEFINE_WAIT(wait); @@ -563,8 +505,6 @@ static void log_flush_commit(struct gfs2_sbd *sdp) } while(atomic_read(&sdp->sd_log_in_flight)); finish_wait(&sdp->sd_log_flush_wait, &wait); } - - log_write_header(sdp, 0, 0); } static int bd_cmp(void *priv, struct list_head *a, struct list_head *b) @@ -633,6 +573,68 @@ static void gfs2_ordered_wait(struct gfs2_sbd *sdp) gfs2_log_unlock(sdp); } +/** + * log_write_header - Get and initialize a journal header buffer + * @sdp: The GFS2 superblock + * + * Returns: the initialized log buffer descriptor + */ + +static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull) +{ + u64 blkno = gfs2_log_bmap(sdp, sdp->sd_log_flush_head); + struct buffer_head *bh; + struct gfs2_log_header *lh; + unsigned int tail; + u32 hash; + + bh = sb_getblk(sdp->sd_vfs, blkno); + lock_buffer(bh); + memset(bh->b_data, 0, bh->b_size); + set_buffer_uptodate(bh); + clear_buffer_dirty(bh); + + gfs2_ail1_empty(sdp); + tail = current_tail(sdp); + + lh = (struct gfs2_log_header *)bh->b_data; + memset(lh, 0, sizeof(struct gfs2_log_header)); + lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC); + lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH); + lh->lh_header.__pad0 = cpu_to_be64(0); + lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH); + lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid); + lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++); + lh->lh_flags = cpu_to_be32(flags); + lh->lh_tail = cpu_to_be32(tail); + lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head); + hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header)); + lh->lh_hash = cpu_to_be32(hash); + + bh->b_end_io = end_buffer_write_sync; + get_bh(bh); + if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) { + gfs2_ordered_wait(sdp); + log_flush_wait(sdp); + submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh); + } else { + submit_bh(WRITE_FLUSH_FUA | REQ_META, bh); + } + wait_on_buffer(bh); + + if (!buffer_uptodate(bh)) + gfs2_io_error_bh(sdp, bh); + brelse(bh); + + if (sdp->sd_log_tail != tail) + log_pull_tail(sdp, tail); + else + gfs2_assert_withdraw(sdp, !pull); + + sdp->sd_log_idle = (tail == sdp->sd_log_flush_head); + gfs2_log_incr_head(sdp); +} + /** * gfs2_log_flush - flush incore transaction(s) * @sdp: the filesystem @@ -676,11 +678,10 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl) gfs2_ordered_write(sdp); lops_before_commit(sdp); - gfs2_ordered_wait(sdp); - if (sdp->sd_log_head != sdp->sd_log_flush_head) - log_flush_commit(sdp); - else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){ + if (sdp->sd_log_head != sdp->sd_log_flush_head) { + log_write_header(sdp, 0, 0); + } else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){ gfs2_log_lock(sdp); atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */ trace_gfs2_log_blocks(sdp, -1); -- 2.20.1