On 01/20/2018 07:27 AM, David Sterba wrote:
On Thu, Jan 18, 2018 at 06:47:17PM +0100, David Sterba wrote:
On Thu, Jan 18, 2018 at 10:02:32PM +0800, Anand Jain wrote:
(Apply on top of my patchset
[PATCH v4 0/6] preparatory work to add device forget
for conflict free apply. They don't actually depend on
each other though).
Cleanup of device_list_add(), mainly in preparation to handle
reappearing missing device which its next reroll will be sent
separately.
I'm adding the two patchsets to the 4.16 queue but will push the updated
branch after the current tests finish and I also test the updated branch
as well.
So this did not survive the first fstests run, I'm going to move the patchset
to the 4.17 dev queue.
[ 2912.493351] run fstests btrfs/064 at 2018-01-19 20:55:50
[ 2914.218654] BTRFS: device fsid ee7e811a-fdb3-42e9-8a81-5ed8e1a4282b devid 1
transid 5 /dev/sdb6
[ 2914.261560] BTRFS: device fsid ee7e811a-fdb3-42e9-8a81-5ed8e1a4282b devid 2
transid 5 /dev/sdc5
[ 2914.296819] BTRFS: device fsid ee7e811a-fdb3-42e9-8a81-5ed8e1a4282b devid 3
transid 5 /dev/sdb7
[ 2914.348140] BTRFS: device fsid ee7e811a-fdb3-42e9-8a81-5ed8e1a4282b devid 4
transid 5 /dev/sdc6
[ 2914.389368] BTRFS: device fsid ee7e811a-fdb3-42e9-8a81-5ed8e1a4282b devid 5
transid 5 /dev/sdb8
[ 2914.425378] BTRFS: device fsid ee7e811a-fdb3-42e9-8a81-5ed8e1a4282b devid 6
transid 5 /dev/sdc7
[ 2914.443497] BTRFS: device fsid ee7e811a-fdb3-42e9-8a81-5ed8e1a4282b devid 7
transid 5 /dev/sdb9
[ 2914.488145] BTRFS info (device sdb9): disk space caching is enabled
[ 2914.494744] BTRFS info (device sdb9): has skinny extents
[ 2914.500328] BTRFS info (device sdb9): flagging fs with big metadata feature
[ 2914.514809] BTRFS info (device sdb9): enabling ssd optimizations
[ 2914.522114] BTRFS info (device sdb9): creating UUID tree
[ 2914.716867] BTRFS info (device sdb9): dev_replace from /dev/sdc5 (devid 2)
to /dev/sdc8 started
[ 2914.852699] BTRFS info (device sdb9): dev_replace from /dev/sdc5 (devid 2)
to /dev/sdc8 finished
[ 2915.028666] BTRFS info (device sdb9): dev_replace from /dev/sdb7 (devid 3)
to /dev/sdc5 started
[ 2915.110374] BTRFS info (device sdb9): dev_replace from /dev/sdb7 (devid 3)
to /dev/sdc5 finished
[ 2915.309674] BTRFS info (device sdb9): dev_replace from /dev/sdc6 (devid 4)
to /dev/sdb7 started
[ 2915.340819] BTRFS info (device sdb9): dev_replace from /dev/sdc6 (devid 4)
to /dev/sdb7 finished
[ 2915.350220] BUG: unable to handle kernel NULL pointer dereference at
0000000000000010
[ 2915.358350] IP: btrfs_scan_one_device+0x127/0x180 [btrfs]
[ 2915.358353] PGD 0 P4D 0
[ 2915.358366] Oops: 0000 [#1] PREEMPT SMP
[ 2915.358493] CPU: 2 PID: 1076 Comm: systemd-udevd Tainted: G W
4.15.0-rc8-1.ge195904-vanilla+ #128
[ 2915.358495] Hardware name: empty empty/S3993, BIOS PAQEX0-3 02/24/2008
[ 2915.358534] RIP: 0010:btrfs_scan_one_device+0x127/0x180 [btrfs]
I couldn't reproduce with btrfs/064 which ran for several iterations.
But a script [1] could trigger the problem.
[1]
---
mkfs.btrfs -fq -draid1 -mraid1 /dev/sdb /dev/sdc
modprobe -r btrfs
mount -o degraded /dev/sdb /btrfs
btrfs repl start -Bf 2 /dev/sdd /btrfs
umount /btrfs
modprobe -r btrfs
btrfs dev scan
btrfs dev scan /dev/sdc
---
Problem was mainly due to the patch 3/4, which tried to access the
return pointer even for the failed condition. The fix is to bring the
device point access under the else part as show below [2]. I have
included this fix in V5. Which is tested with btrfs xfstests.
Pls could you consider v5 for 4.16 ?
[2]
-----
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 462bae3627e3..a86c3a14ec89 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1214,8 +1214,8 @@ int btrfs_scan_one_device(const char *path,
fmode_t flags, void *holder,
mutex_unlock(&uuid_mutex);
if (IS_ERR(device))
ret = PTR_ERR(device);
-
- *fs_devices_ret = device->fs_devices;
+ else
+ *fs_devices_ret = device->fs_devices;
btrfs_release_disk_super(page);
------
Thanks, Anand
[ 2915.358537] RSP: 0018:ffffb35a4524be30 EFLAGS: 00010206
[ 2915.358541] RAX: fffffffffffffff0 RBX: 0000000000000081 RCX: 000000000000000f
[ 2915.358544] RDX: ffff96a791c7e10b RSI: 0000000000000001 RDI: ffff96a79f734200
[ 2915.358546] RBP: ffff96a7a2ea6000 R08: 000000000000002b R09: 0000000000000000
[ 2915.358548] R10: 0000000000000000 R11: 0000000000000004 R12: 00000000fffffff0
[ 2915.358550] R13: ffffb35a4524be60 R14: fffff07d48471f80 R15: 000055ee5775ad74
[ 2915.358554] FS: 00007f736b3648c0(0000) GS:ffff96a7a6a00000(0000)
knlGS:0000000000000000
[ 2915.358556] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2915.358558] CR2: 0000000000000010 CR3: 000000021201e000 CR4: 00000000000006e0
[ 2915.358560] Call Trace:
[ 2915.358600] btrfs_control_ioctl+0xad/0xe0 [btrfs]
[ 2915.358610] ? trace_hardirqs_on_caller+0xf2/0x1a0
[ 2915.358618] do_vfs_ioctl+0x90/0x6b0
[ 2915.358625] ? __audit_syscall_entry+0xb5/0x110
[ 2915.358632] ? syscall_trace_enter+0x1ae/0x360
[ 2915.358638] ? return_from_SYSCALL_64+0x10/0x75
[ 2915.358643] SyS_ioctl+0x74/0x80
[ 2915.358647] ? do_syscall_64+0x1e/0x1a0
[ 2915.358653] do_syscall_64+0x64/0x1a0
[ 2915.358659] entry_SYSCALL64_slow_path+0x25/0x25
[ 2915.358663] RIP: 0033:0x7f736a1f3227
[ 2915.358665] RSP: 002b:00007fff9dcad618 EFLAGS: 00000246 ORIG_RAX:
0000000000000010
[ 2915.358669] RAX: ffffffffffffffda RBX: 00007fff9dcad630 RCX: 00007f736a1f3227
[ 2915.358670] RDX: 00007fff9dcad630 RSI: 0000000090009427 RDI: 000000000000000f
[ 2915.358672] RBP: 000000000000000f R08: 376264732f766564 R09: 0000000000000003
[ 2915.358674] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
[ 2915.358676] R13: 000055ee59813e90 R14: 0000000000000000 R15: 000055ee5775ad74
[ 2915.358810] RIP: btrfs_scan_one_device+0x127/0x180 [btrfs] RSP:
ffffb35a4524be30
[ 2915.358812] CR2: 0000000000000010
[ 2915.358970] ---[ end trace 900a4fff1ad9ece2 ]---
[ 2915.441581] BTRFS info (device sdb9): dev_replace from /dev/sdb8 (devid 5)
to /dev/sdc6 started
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