From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Ilya Dryomov <idryomov@gmail.com>,
Dongsheng Yang <dongsheng.yang@easystack.cn>
Subject: [PATCH 4.9 12/16] rbd: dont return 0 on unmap if RBD_DEV_FLAG_REMOVING is set
Date: Tue, 15 Jan 2019 17:35:55 +0100 [thread overview]
Message-ID: <20190115154849.555626084@linuxfoundation.org> (raw)
In-Reply-To: <20190115154848.164648613@linuxfoundation.org>
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ilya Dryomov <idryomov@gmail.com>
commit 85f5a4d666fd9be73856ed16bb36c5af5b406b29 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/rbd.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -6346,7 +6346,6 @@ static ssize_t do_rbd_remove(struct bus_
struct list_head *tmp;
int dev_id;
char opt_buf[6];
- bool already = false;
bool force = false;
int ret;
@@ -6379,13 +6378,13 @@ static ssize_t do_rbd_remove(struct 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) {
next prev parent reply other threads:[~2019-01-15 16:39 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 16:35 [PATCH 4.9 00/16] 4.9.151-stable review Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 01/16] ALSA: hda/realtek - Disable headset Mic VREF for headset mode of ALC225 Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 02/16] CIFS: Do not hide EINTR after sending network packets Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 03/16] cifs: Fix potential OOB access of lock element array Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 04/16] usb: cdc-acm: send ZLP for Telit 3G Intel based modems Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 05/16] USB: storage: dont insert sane sense for SPC3+ when bad sense specified Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 06/16] USB: storage: add quirk for SMI SM3350 Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 07/16] USB: Add USB_QUIRK_DELAY_CTRL_MSG quirk for Corsair K70 RGB Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 08/16] slab: alien caches must not be initialized if the allocation of the alien cache failed Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 09/16] mm: page_mapped: dont assume compound page is huge or THP Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 10/16] ACPI: power: Skip duplicate power resource references in _PRx Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 11/16] i2c: dev: prevent adapter retries and timeout being set as minus value Greg Kroah-Hartman
2019-01-15 16:35 ` Greg Kroah-Hartman [this message]
2019-01-15 16:35 ` [PATCH 4.9 13/16] ext4: make sure enough credits are reserved for dioread_nolock writes Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 14/16] ext4: fix a potential fiemap/page fault deadlock w/ inline_data Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 15/16] ext4: avoid kernel warning when writing the superblock to a dead device Greg Kroah-Hartman
2019-01-15 16:35 ` [PATCH 4.9 16/16] sunrpc: use-after-free in svc_process_common() Greg Kroah-Hartman
2019-01-16 1:36 ` [PATCH 4.9 00/16] 4.9.151-stable review shuah
2019-01-16 9:23 ` Jon Hunter
2019-01-16 11:52 ` Naresh Kamboju
2019-01-16 20:37 ` Guenter Roeck
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