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| 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/linear.c | |
| parent | 63f700aab4c11d46626de3cd051dae56cf7e9056 (diff) | |
| download | op-kernel-dev-cc27b0c78c79680d128dbac79de0d40556d041bb.zip op-kernel-dev-cc27b0c78c79680d128dbac79de0d40556d041bb.tar.gz | |
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/linear.c')
| -rw-r--r-- | drivers/md/linear.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/md/linear.c b/drivers/md/linear.c index df6f2c9..5f1eb91 100644 --- a/drivers/md/linear.c +++ b/drivers/md/linear.c @@ -245,7 +245,7 @@ static void linear_free(struct mddev *mddev, void *priv) kfree(conf); } -static void linear_make_request(struct mddev *mddev, struct bio *bio) +static bool linear_make_request(struct mddev *mddev, struct bio *bio) { char b[BDEVNAME_SIZE]; struct dev_info *tmp_dev; @@ -254,7 +254,7 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio) if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { md_flush_request(mddev, bio); - return; + return true; } tmp_dev = which_dev(mddev, bio_sector); @@ -292,7 +292,7 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio) mddev_check_write_zeroes(mddev, bio); generic_make_request(bio); } - return; + return true; out_of_bounds: pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %s: %llu sectors, offset %llu\n", @@ -302,6 +302,7 @@ out_of_bounds: (unsigned long long)tmp_dev->rdev->sectors, (unsigned long long)start_sector); bio_io_error(bio); + return true; } static void linear_status (struct seq_file *seq, struct mddev *mddev) |
