From: David Jeffery djeffery@redhat.com
commit 775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1 upstream.
If pers->make_request fails in md_flush_request(), the bio is lost. To fix this, pass back a bool to indicate if the original make_request call should continue to handle the I/O and instead of assuming the flush logic will push it to completion.
Convert md_flush_request to return a bool and no longer calls the raid driver's make_request function. If the return is true, then the md flush logic has or will complete the bio and the md make_request call is done. If false, then the md make_request function needs to keep processing like it is a normal bio. Let the original call to md_handle_request handle any need to retry sending the bio to the raid driver's make_request function should it be needed.
Also mark md_flush_request and the make_request function pointer as __must_check to issue warnings should these critical return values be ignored.
Fixes: 2bc13b83e629 ("md: batch flush requests.") Cc: stable@vger.kernel.org # # v4.19+ Cc: NeilBrown neilb@suse.com Signed-off-by: David Jeffery djeffery@redhat.com Reviewed-by: Xiao Ni xni@redhat.com Signed-off-by: Song Liu songliubraving@fb.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/md-linear.c | 5 ++--- drivers/md/md-multipath.c | 5 ++--- drivers/md/md.c | 11 +++++++++-- drivers/md/md.h | 4 ++-- drivers/md/raid0.c | 5 ++--- drivers/md/raid1.c | 5 ++--- drivers/md/raid10.c | 5 ++--- drivers/md/raid5.c | 4 ++-- 8 files changed, 23 insertions(+), 21 deletions(-)
--- a/drivers/md/md-linear.c +++ b/drivers/md/md-linear.c @@ -252,10 +252,9 @@ static bool linear_make_request(struct m sector_t start_sector, end_sector, data_offset; sector_t bio_sector = bio->bi_iter.bi_sector;
- if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { - md_flush_request(mddev, bio); + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) return true; - }
tmp_dev = which_dev(mddev, bio_sector); start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; --- a/drivers/md/md-multipath.c +++ b/drivers/md/md-multipath.c @@ -112,10 +112,9 @@ static bool multipath_make_request(struc struct multipath_bh * mp_bh; struct multipath_info *multipath;
- if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { - md_flush_request(mddev, bio); + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) return true; - }
mp_bh = mempool_alloc(&conf->pool, GFP_NOIO);
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -487,7 +487,13 @@ static void md_submit_flush_data(struct } }
-void md_flush_request(struct mddev *mddev, struct bio *bio) +/* + * Manages consolidation of flushes and submitting any flushes needed for + * a bio with REQ_PREFLUSH. Returns true if the bio is finished or is + * being finished in another context. Returns false if the flushing is + * complete but still needs the I/O portion of the bio to be processed. + */ +bool md_flush_request(struct mddev *mddev, struct bio *bio) { ktime_t start = ktime_get_boottime(); spin_lock_irq(&mddev->lock); @@ -512,9 +518,10 @@ void md_flush_request(struct mddev *mdde bio_endio(bio); else { bio->bi_opf &= ~REQ_PREFLUSH; - mddev->pers->make_request(mddev, bio); + return false; } } + return true; } EXPORT_SYMBOL(md_flush_request);
--- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -532,7 +532,7 @@ struct md_personality int level; struct list_head list; struct module *owner; - bool (*make_request)(struct mddev *mddev, struct bio *bio); + bool __must_check (*make_request)(struct mddev *mddev, struct bio *bio); /* * start up works that do NOT require md_thread. tasks that * requires md_thread should go into start() @@ -684,7 +684,7 @@ extern void md_error(struct mddev *mddev extern void md_finish_reshape(struct mddev *mddev);
extern int mddev_congested(struct mddev *mddev, int bits); -extern void md_flush_request(struct mddev *mddev, struct bio *bio); +extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio); extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev, sector_t sector, int size, struct page *page); extern int md_super_wait(struct mddev *mddev); --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -580,10 +580,9 @@ static bool raid0_make_request(struct md unsigned chunk_sects; unsigned sectors;
- if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { - md_flush_request(mddev, bio); + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) return true; - }
if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) { raid0_handle_discard(mddev, bio); --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1537,10 +1537,9 @@ static bool raid1_make_request(struct md { sector_t sectors;
- if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { - md_flush_request(mddev, bio); + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) return true; - }
/* * There is a limit to the maximum size, but --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1562,10 +1562,9 @@ static bool raid10_make_request(struct m int chunk_sects = chunk_mask + 1; int sectors = bio_sectors(bio);
- if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { - md_flush_request(mddev, bio); + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) return true; - }
if (!md_write_start(mddev, bio)) return false; --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5590,8 +5590,8 @@ static bool raid5_make_request(struct md if (ret == 0) return true; if (ret == -ENODEV) { - md_flush_request(mddev, bi); - return true; + if (md_flush_request(mddev, bi)) + return true; } /* ret == -EAGAIN, fallback */ /*