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| author | Ilya Dryomov <idryomov@gmail.com> | 2019-01-08 19:47:38 +0100 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2019-01-10 09:45:09 +0100 |
| commit | 85f5a4d666fd9be73856ed16bb36c5af5b406b29 (patch) | |
| tree | 478748726b2075e0db2221d2553d46aa38f4edd5 /drivers/block/rbd.c | |
| parent | c64a2b0516a02361d8deb1f038647c29020d0852 (diff) | |
| download | lwn-85f5a4d666fd9be73856ed16bb36c5af5b406b29.tar.gz lwn-85f5a4d666fd9be73856ed16bb36c5af5b406b29.zip | |
rbd: don't return 0 on unmap if RBD_DEV_FLAG_REMOVING is set
There is a window between when RBD_DEV_FLAG_REMOVING is set and when
the device is removed from rbd_dev_list. During this window, we set
"already" and return 0.
Returning 0 from write(2) can confuse userspace tools because
0 indicates that nothing was written. In particular, "rbd unmap"
will retry the write multiple times a second:
10:28:05.463299 write(4, "0", 1) = 0
10:28:05.463509 write(4, "0", 1) = 0
10:28:05.463720 write(4, "0", 1) = 0
10:28:05.463942 write(4, "0", 1) = 0
10:28:05.464155 write(4, "0", 1) = 0
Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Tested-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
Diffstat (limited to 'drivers/block/rbd.c')
| -rw-r--r-- | drivers/block/rbd.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 8e5140bbf241..1e92b61d0bd5 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5986,7 +5986,6 @@ static ssize_t do_rbd_remove(struct bus_type *bus, struct list_head *tmp; int dev_id; char opt_buf[6]; - bool already = false; bool force = false; int ret; @@ -6019,13 +6018,13 @@ static ssize_t do_rbd_remove(struct bus_type *bus, spin_lock_irq(&rbd_dev->lock); if (rbd_dev->open_count && !force) ret = -EBUSY; - else - already = test_and_set_bit(RBD_DEV_FLAG_REMOVING, - &rbd_dev->flags); + else if (test_and_set_bit(RBD_DEV_FLAG_REMOVING, + &rbd_dev->flags)) + ret = -EINPROGRESS; spin_unlock_irq(&rbd_dev->lock); } spin_unlock(&rbd_dev_list_lock); - if (ret < 0 || already) + if (ret) return ret; if (force) { |