[PATCH v2 6/6] xfs: add log recovery tracepoint for head/tail

Brian Foster
2017-07-10T13:28:02Z

Torn write detection and tail overwrite detection can shift the log
head and tail respectively in the event of CRC mismatch or
corruption errors. Add a high-level log recovery tracepoint to dump
the final log head/tail and make those values easily attainable in
debug/diagnostic situations.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/xfs_log_recover.c | 2 ++
fs/xfs/xfs_trace.h | 18 ++++++++++++++++++
2 files changed, 20 insertions(+)

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 2e34797..dd2ad2a 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -5598,6 +5598,8 @@ xlog_do_recover(
xfs_buf_t *bp;
xfs_sb_t *sbp;

+ trace_xfs_log_recover(log, head_blk, tail_blk);
+
/*
* First replay the images in the log.
*/
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index bcc3cdf..6881047 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1963,6 +1963,24 @@ DEFINE_EVENT(xfs_swap_extent_class, name, \
DEFINE_SWAPEXT_EVENT(xfs_swap_extent_before);
DEFINE_SWAPEXT_EVENT(xfs_swap_extent_after);

+TRACE_EVENT(xfs_log_recover,
+ TP_PROTO(struct xlog *log, xfs_daddr_t headblk, xfs_daddr_t tailblk),
+ TP_ARGS(log, headblk, tailblk),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_daddr_t, headblk)
+ __field(xfs_daddr_t, tailblk)
+ ),
+ TP_fast_assign(
+ __entry->dev = log->l_mp->m_super->s_dev;
+ __entry->headblk = headblk;
+ __entry->tailblk = tailblk;
+ ),
+ TP_printk("dev %d:%d headblk 0x%llx tailblk 0x%llx",
+ MAJOR(__entry->dev), MINOR(__entry->dev), __entry->headblk,
+ __entry->tailblk)
+)
+
TRACE_EVENT(xfs_log_recover_record,
TP_PROTO(struct xlog *log, struct xlog_rec_header *rhead, int pass),
TP_ARGS(log, rhead, pass),
--
2.9.4