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authorNeilBrown <neilb@suse.com>2017-06-05 08:49:39 +0200
committerShaohua Li <shli@fb.com>2017-06-13 19:18:01 +0200
commitcc27b0c78c79680d128dbac79de0d40556d041bb (patch)
tree1f32d4acd29d825eecc1aef90d423cdacea8121c /drivers/md/linear.c
parentMerge tag 'xtensa-20170612' of git://github.com/jcmvbkbc/linux-xtensa (diff)
downloadlinux-cc27b0c78c79680d128dbac79de0d40556d041bb.tar.xz
linux-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/linear.c')
-rw-r--r--drivers/md/linear.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index df6f2c98eca7..5f1eb9189542 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)