diff options
| author | Edward Hsieh <edwardh@synology.com> | 2021-06-24 15:30:30 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-14 17:59:42 +0300 |
| commit | 577072de4d61c36f66b4c8c0f2dac21440b2d750 (patch) | |
| tree | 73edaf796f3c969db82a589f9584838795f99b03 /block | |
| parent | ca469162356b051630be5dfe0fdeb539b5bad3ed (diff) | |
| download | linux-577072de4d61c36f66b4c8c0f2dac21440b2d750.tar.xz | |
block: fix trace completion for chained bio
[ Upstream commit 60b6a7e6a0f4382cd689f9afdac816964fec2921 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bio.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/block/bio.c b/block/bio.c index 50e579088aca..b00c5a88a743 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1412,8 +1412,7 @@ 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) { @@ -1426,6 +1425,11 @@ 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 @@ -1439,11 +1443,6 @@ 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); |