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authorEdward Hsieh <edwardh@synology.com>2021-06-24 15:30:30 +0300
committerJens Axboe <axboe@kernel.dk>2021-06-24 18:53:50 +0300
commit60b6a7e6a0f4382cd689f9afdac816964fec2921 (patch)
tree7b5fd7251cbc4c3430b61ff3b641b651bc1f6da4 /block
parentddcc5c544eb0991501761622b651cf43ce660a22 (diff)
downloadlinux-60b6a7e6a0f4382cd689f9afdac816964fec2921.tar.xz
block: fix trace completion for chained bio
For chained bio, trace_block_bio_complete in bio_endio is currently called only by the parent bio once upon all chained bio completed. However, the sector and size for the parent bio are modified in bio_split. Therefore, the size and sector of the complete events might not match the queue events in blktrace. The original fix of bio completion trace <fbbaf700e7b1> ("block: trace completion of all bios.") wants multiple complete events to correspond to one queue event but missed this. The issue can be reproduced by md/raid5 read with bio cross chunks. To fix, move trace completion into the loop for every chained bio to call. Fixes: fbbaf700e7b1 ("block: trace completion of all bios.") Reviewed-by: Wade Liang <wadel@synology.com> Reviewed-by: BingJing Chang <bingjingc@synology.com> Signed-off-by: Edward Hsieh <edwardh@synology.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210624123030.27014-1-edwardh@synology.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/bio.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/block/bio.c b/block/bio.c
index 44205dfb6b60..1fab762e079b 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1375,8 +1375,7 @@ static inline bool bio_remaining_done(struct bio *bio)
*
* bio_endio() can be called several times on a bio that has been chained
* using bio_chain(). The ->bi_end_io() function will only be called the
- * last time. At this point the BLK_TA_COMPLETE tracing event will be
- * generated if BIO_TRACE_COMPLETION is set.
+ * last time.
**/
void bio_endio(struct bio *bio)
{
@@ -1389,6 +1388,11 @@ again:
if (bio->bi_bdev)
rq_qos_done_bio(bio->bi_bdev->bd_disk->queue, bio);
+ if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
+ trace_block_bio_complete(bio->bi_bdev->bd_disk->queue, bio);
+ bio_clear_flag(bio, BIO_TRACE_COMPLETION);
+ }
+
/*
* Need to have a real endio function for chained bios, otherwise
* various corner cases will break (like stacking block devices that
@@ -1402,11 +1406,6 @@ again:
goto again;
}
- if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
- trace_block_bio_complete(bio->bi_bdev->bd_disk->queue, bio);
- bio_clear_flag(bio, BIO_TRACE_COMPLETION);
- }
-
blk_throtl_bio_endio(bio);
/* release cgroup info */
bio_uninit(bio);