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From: David Sterba <dsterba@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: David Sterba <dsterba@suse.com>
Subject: [PATCH 07/11] btrfs: dev_alloc_list is not protected by RCU, use normal list_del
Date: Tue, 31 Oct 2017 18:44:47 +0100	[thread overview]
Message-ID: <2e58a1fff7b50e0b210d05ea9f2314785c6e047c.1509471604.git.dsterba@suse.com> (raw)
In-Reply-To: <cover.1509471604.git.dsterba@suse.com>

The dev_alloc_list list could be protected by various mutexes,
depending on the context. The list tracks devices that can take part of
allocating new chunks, so the closest mutex is chunk_mutex. Adding a new
device from inside the ADD_DEV ioctl will need device_list_mutex and
registering a new device from the ioctl needs uuid_mutex.

All mutexes naturally guarantee exclusivity against the same context.
The device ownership can move between the contexts and the exclusivity
is guaranteed by other means, eg. during the mount with the uuid_mutex.

There's no RCU involved for dev_alloc_list.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/volumes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 098affc58361..6e45751ed957 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2054,7 +2054,7 @@ void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
 	fs_devices = srcdev->fs_devices;
 
 	list_del_rcu(&srcdev->dev_list);
-	list_del_rcu(&srcdev->dev_alloc_list);
+	list_del(&srcdev->dev_alloc_list);
 	fs_devices->num_devices--;
 	if (srcdev->missing)
 		fs_devices->missing_devices--;
-- 
2.14.0


  parent reply	other threads:[~2017-10-31 17:46 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-31 17:44 [PATCH 00/11] Device fixes and cleanups David Sterba
2017-10-31 17:44 ` [PATCH 01/11] btrfs: add missing device::flush_bio puts David Sterba
2017-11-02  9:41   ` Nikolay Borisov
2017-11-06 13:24     ` David Sterba
2017-11-02 10:40   ` Anand Jain
2017-10-31 17:44 ` [PATCH 02/11] btrfs: rename device free rcu helper to free_device_rcu David Sterba
2017-10-31 17:44 ` [PATCH 03/11] btrfs: introduce free_device helper David Sterba
2017-10-31 17:44 ` [PATCH 04/11] btrfs: use free_device where opencoded David Sterba
2017-11-02 11:25   ` Anand Jain
2017-10-31 17:44 ` [PATCH 05/11] btrfs: simplify exit paths in btrfs_init_new_device David Sterba
2017-11-06  1:53   ` Anand Jain
2017-10-31 17:44 ` [PATCH 06/11] btrfs: document device locking David Sterba
2017-11-02 10:29   ` Nikolay Borisov
2017-11-06 13:51     ` David Sterba
2017-11-06 15:02       ` Nikolay Borisov
2017-11-06 15:09         ` David Sterba
2017-11-03 11:13   ` Anand Jain
2017-11-06  2:32     ` Anand Jain
2017-11-06 13:40       ` David Sterba
2017-11-06 13:36     ` David Sterba
2017-10-31 17:44 ` David Sterba [this message]
2017-10-31 17:44 ` [PATCH 08/11] btrfs: simplify btrfs_close_bdev David Sterba
2017-10-31 17:44 ` [PATCH 09/11] btrfs: switch to RCU for device traversal in btrfs_ioctl_dev_info David Sterba
2017-10-31 17:44 ` [PATCH 10/11] btrfs: switch to RCU for device traversal in btrfs_ioctl_fs_info David Sterba
2017-10-31 17:44 ` [PATCH 11/11] btrfs: use non-RCU list traversal in write_all_supers callees David Sterba
2017-11-02  9:49   ` Nikolay Borisov
2017-11-06 13:59     ` David Sterba

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