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authorDavid Jeffery <djeffery@redhat.com>2019-09-16 19:15:14 +0200
committerSong Liu <songliubraving@fb.com>2019-10-25 00:22:40 +0200
commit775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1 (patch)
tree28d988a5036c9125106d3d18cd3ee3078bcfee7a /drivers
parentmd/bitmap: avoid race window between md_bitmap_resize and bitmap_file_clear_bit (diff)
downloadlinux-775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1.tar.xz
linux-775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1.zip
md: improve handling of bio with REQ_PREFLUSH in md_flush_request()
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/md-linear.c5
-rw-r--r--drivers/md/md-multipath.c5
-rw-r--r--drivers/md/md.c11
-rw-r--r--drivers/md/md.h4
-rw-r--r--drivers/md/raid0.c5
-rw-r--r--drivers/md/raid1.c5
-rw-r--r--drivers/md/raid10.c5
-rw-r--r--drivers/md/raid5.c4
8 files changed, 23 insertions, 21 deletions
diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
index c766c559d36d..26c75c0199fa 100644
--- a/drivers/md/md-linear.c
+++ b/drivers/md/md-linear.c
@@ -244,10 +244,9 @@ static bool linear_make_request(struct mddev *mddev, struct bio *bio)
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;
diff --git a/drivers/md/md-multipath.c b/drivers/md/md-multipath.c
index 6780938d2991..152f9e65a226 100644
--- a/drivers/md/md-multipath.c
+++ b/drivers/md/md-multipath.c
@@ -104,10 +104,9 @@ static bool multipath_make_request(struct mddev *mddev, struct bio * bio)
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);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 1be7abeb24fd..b8dd56b746da 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -550,7 +550,13 @@ static void md_submit_flush_data(struct work_struct *ws)
}
}
-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);
@@ -575,9 +581,10 @@ void md_flush_request(struct mddev *mddev, struct bio *bio)
bio_endio(bio);
else {
bio->bi_opf &= ~REQ_PREFLUSH;
- mddev->pers->make_request(mddev, bio);
+ return false;
}
}
+ return true;
}
EXPORT_SYMBOL(md_flush_request);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index c5e3ff398b59..5f86f8adb0a4 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -550,7 +550,7 @@ 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()
@@ -703,7 +703,7 @@ extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
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);
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 3956ea502f97..f2b83bd2fee6 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -575,10 +575,9 @@ static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
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);
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 0466ee2453b4..bb29aeefcbd0 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1567,10 +1567,9 @@ static bool raid1_make_request(struct mddev *mddev, struct bio *bio)
{
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
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 299c7b1c9718..2eca0a81a8c9 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1525,10 +1525,9 @@ static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
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;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 223e97ab27e6..12a8ce83786e 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5592,8 +5592,8 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
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 */
/*