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| author | Heinz Mauelshagen <heinzm@redhat.com> | 2018-02-02 23:13:19 +0100 |
|---|---|---|
| committer | Shaohua Li <sh.li@alibaba-inc.com> | 2018-02-18 10:11:59 -0800 |
| commit | 4b6c1060eaa6495aa5b0032e8f2d51dd936b1257 (patch) | |
| tree | 6060f030df613e4b68d18bc6c150bdfa02077444 | |
| parent | b126194cbb799f9980b92a77e58db6ad794c8082 (diff) | |
| download | linux-0-day-4b6c1060eaa6495aa5b0032e8f2d51dd936b1257.tar.gz linux-0-day-4b6c1060eaa6495aa5b0032e8f2d51dd936b1257.tar.xz | |
md: fix md_write_start() deadlock w/o metadata devices
If no metadata devices are configured on raid1/4/5/6/10
(e.g. via dm-raid), md_write_start() unconditionally waits
for superblocks to be written thus deadlocking.
Fix introduces mddev->has_superblocks bool, defines it in md_run()
and checks for it in md_write_start() to conditionally avoid waiting.
Once on it, check for non-existing superblocks in md_super_write().
Link: https://bugzilla.kernel.org/show_bug.cgi?id=198647
Fixes: cc27b0c78c796 ("md: fix deadlock between mddev_suspend() and md_write_start()")
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Shaohua Li <sh.li@alibaba-inc.com>
| -rw-r--r-- | drivers/md/md.c | 10 | ||||
| -rw-r--r-- | drivers/md/md.h | 2 |
2 files changed, 12 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index bcf4ab9ab3df1..9b73cf139b800 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -801,6 +801,9 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev, struct bio *bio; int ff = 0; + if (!page) + return; + if (test_bit(Faulty, &rdev->flags)) return; @@ -5452,6 +5455,7 @@ int md_run(struct mddev *mddev) * the only valid external interface is through the md * device. */ + mddev->has_superblocks = false; rdev_for_each(rdev, mddev) { if (test_bit(Faulty, &rdev->flags)) continue; @@ -5465,6 +5469,9 @@ int md_run(struct mddev *mddev) set_disk_ro(mddev->gendisk, 1); } + if (rdev->sb_page) + mddev->has_superblocks = true; + /* perform some consistency tests on the device. * We don't want the data to overlap the metadata, * Internal Bitmap issues have been handled elsewhere. @@ -8065,6 +8072,7 @@ EXPORT_SYMBOL(md_done_sync); bool md_write_start(struct mddev *mddev, struct bio *bi) { int did_change = 0; + if (bio_data_dir(bi) != WRITE) return true; @@ -8097,6 +8105,8 @@ bool md_write_start(struct mddev *mddev, struct bio *bi) rcu_read_unlock(); if (did_change) sysfs_notify_dirent_safe(mddev->sysfs_state); + if (!mddev->has_superblocks) + return true; wait_event(mddev->sb_wait, !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) || mddev->suspended); diff --git a/drivers/md/md.h b/drivers/md/md.h index 58cd20a5e85ed..fbc925cce8107 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -468,6 +468,8 @@ struct mddev { void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev); struct md_cluster_info *cluster_info; unsigned int good_device_nr; /* good device num within cluster raid */ + + bool has_superblocks:1; }; enum recovery_flags { |