diff options
| author | NeilBrown <neilb@suse.com> | 2017-06-05 16:49:39 +1000 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2017-06-13 10:18:01 -0700 |
| commit | cc27b0c78c79680d128dbac79de0d40556d041bb (patch) | |
| tree | 1f32d4acd29d825eecc1aef90d423cdacea8121c /drivers/md/faulty.c | |
| parent | 63f700aab4c11d46626de3cd051dae56cf7e9056 (diff) | |
| download | lwn-cc27b0c78c79680d128dbac79de0d40556d041bb.tar.gz lwn-cc27b0c78c79680d128dbac79de0d40556d041bb.zip | |
md: fix deadlock between mddev_suspend() and md_write_start()
If mddev_suspend() races with md_write_start() we can deadlock
with mddev_suspend() waiting for the request that is currently
in md_write_start() to complete the ->make_request() call,
and md_write_start() waiting for the metadata to be updated
to mark the array as 'dirty'.
As metadata updates done by md_check_recovery() only happen then
the mddev_lock() can be claimed, and as mddev_suspend() is often
called with the lock held, these threads wait indefinitely for each
other.
We fix this by having md_write_start() abort if mddev_suspend()
is happening, and ->make_request() aborts if md_write_start()
aborted.
md_make_request() can detect this abort, decrease the ->active_io
count, and wait for mddev_suspend().
Reported-by: Nix <nix@esperi.org.uk>
Fix: 68866e425be2(MD: no sync IO while suspended)
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/faulty.c')
| -rw-r--r-- | drivers/md/faulty.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c index b0536cfd8e17..06a64d5d8c6c 100644 --- a/drivers/md/faulty.c +++ b/drivers/md/faulty.c @@ -170,7 +170,7 @@ static void add_sector(struct faulty_conf *conf, sector_t start, int mode) conf->nfaults = n+1; } -static void faulty_make_request(struct mddev *mddev, struct bio *bio) +static bool faulty_make_request(struct mddev *mddev, struct bio *bio) { struct faulty_conf *conf = mddev->private; int failit = 0; @@ -182,7 +182,7 @@ static void faulty_make_request(struct mddev *mddev, struct bio *bio) * just fail immediately */ bio_io_error(bio); - return; + return true; } if (check_sector(conf, bio->bi_iter.bi_sector, @@ -224,6 +224,7 @@ static void faulty_make_request(struct mddev *mddev, struct bio *bio) bio->bi_bdev = conf->rdev->bdev; generic_make_request(bio); + return true; } static void faulty_status(struct seq_file *seq, struct mddev *mddev) |