[Cluster-devel] [PATCH 01/15] gfs2: log error reform

[Bob Peterson]

Before this patch, gfs2 kept track of journal io errors in two
places (sd_log_error and the SDF_AIL1_IO_ERROR flag in sd_flags.
This patch consolidates the two by eliminating the SDF_AIL1_IO_ERROR
flag in favor of an atomic count of journal errors, sd_log_errors.
When the first io error occurs and its value is incremented to 1,
sd_log_error is set. Thus, sd_log_error reflects the first error
we encountered writing to the journal. In future patches, we will
take advantage of this by checking a single value (sd_log_errors)
rather than having to check both the flag and the sd_log_error
when reacting to io errors.

Signed-off-by: Bob Peterson <rpeterso at redhat.com>
---
 fs/gfs2/incore.h     | 4 ++--
 fs/gfs2/log.c        | 7 ++++---
 fs/gfs2/lops.c       | 7 +++++--
 fs/gfs2/ops_fstype.c | 1 +
 fs/gfs2/quota.c      | 6 ++++--
 5 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index cdf07b408f54..76336b592030 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -620,7 +620,6 @@ enum {
 	SDF_RORECOVERY		= 7, /* read only recovery */
 	SDF_SKIP_DLM_UNLOCK	= 8,
 	SDF_FORCE_AIL_FLUSH     = 9,
-	SDF_AIL1_IO_ERROR	= 10,
 };
 
 enum gfs2_freeze_state {
@@ -829,7 +828,8 @@ struct gfs2_sbd {
 	atomic_t sd_log_in_flight;
 	struct bio *sd_log_bio;
 	wait_queue_head_t sd_log_flush_wait;
-	int sd_log_error;
+	int sd_log_error; /* First log error */
+	atomic_t sd_log_errors; /* Count of log errors */
 
 	atomic_t sd_reserving_log;
 	wait_queue_head_t sd_reserving_log_wait;
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 5bfaf381921a..2393fa758115 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -109,8 +109,8 @@ __acquires(&sdp->sd_ail_lock)
 
 		if (!buffer_busy(bh)) {
 			if (!buffer_uptodate(bh) &&
-			    !test_and_set_bit(SDF_AIL1_IO_ERROR,
-					      &sdp->sd_flags)) {
+			    atomic_add_return(1, &sdp->sd_log_errors) == 1) {
+				sdp->sd_log_error = -EIO;
 				gfs2_io_error_bh(sdp, bh);
 				*withdraw = true;
 			}
@@ -209,7 +209,8 @@ static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 		if (buffer_busy(bh))
 			continue;
 		if (!buffer_uptodate(bh) &&
-		    !test_and_set_bit(SDF_AIL1_IO_ERROR, &sdp->sd_flags)) {
+		    atomic_add_return(1, &sdp->sd_log_errors) == 1) {
+			sdp->sd_log_error = -EIO;
 			gfs2_io_error_bh(sdp, bh);
 			*withdraw = true;
 		}
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 94dcab655bc0..0ff32e96c9f5 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -210,8 +210,11 @@ static void gfs2_end_log_write(struct bio *bio)
 	int i;
 
 	if (bio->bi_status) {
-		fs_err(sdp, "Error %d writing to journal, jid=%u\n",
-		       bio->bi_status, sdp->sd_jdesc->jd_jid);
+		if (atomic_add_return(1, &sdp->sd_log_errors) == 1) {
+			sdp->sd_log_error = bio->bi_status;
+			fs_err(sdp, "Error %d writing to journal, jid=%u\n",
+			       bio->bi_status, sdp->sd_jdesc->jd_jid);
+		}
 		wake_up(&sdp->sd_logd_waitq);
 	}
 
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 1179763f6370..ec503afc07bb 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -130,6 +130,7 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
 
 	init_rwsem(&sdp->sd_log_flush_lock);
 	atomic_set(&sdp->sd_log_in_flight, 0);
+	atomic_set(&sdp->sd_log_errors, 0);
 	atomic_set(&sdp->sd_reserving_log, 0);
 	init_waitqueue_head(&sdp->sd_reserving_log_wait);
 	init_waitqueue_head(&sdp->sd_log_flush_wait);
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 2ae5a109eea7..009172ef4dfe 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -1479,8 +1479,10 @@ static void quotad_error(struct gfs2_sbd *sdp, const char *msg, int error)
 	if (error == 0 || error == -EROFS)
 		return;
 	if (!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) {
-		fs_err(sdp, "gfs2_quotad: %s error %d\n", msg, error);
-		sdp->sd_log_error = error;
+		if (atomic_add_return(1, &sdp->sd_log_errors) == 1) {
+			sdp->sd_log_error = error;
+			fs_err(sdp, "gfs2_quotad: %s error %d\n", msg, error);
+		}
 		wake_up(&sdp->sd_logd_waitq);
 	}
 }
-- 
2.20.1