ceph: remove fragile __map_osds optimization
We used to try to avoid freeing and then reallocating the osd struct. This is a bit fragile due to potential interactions with other references (beyond o_requests), and may be the cause of this crash: [120633.442358] BUG: unable to handle kernel NULL pointer dereference at (null) [120633.443292] IP: [<ffffffff812549b6>] rb_erase+0x11d/0x277 [120633.443292] PGD f7ff3067 PUD f7f53067 PMD 0 [120633.443292] Oops: 0000 [#1] PREEMPT SMP [120633.443292] last sysfs file: /sys/kernel/uevent_seqnum [120633.443292] CPU 1 [120633.443292] Modules linked in: ceph fan ac battery psmouse ehci_hcd ide_pci_generic ohci_hcd thermal processor button [120633.443292] Pid: 3023, comm: ceph-msgr/1 Not tainted 2.6.32-rc2 #12 H8SSL [120633.443292] RIP: 0010:[<ffffffff812549b6>] [<ffffffff812549b6>] rb_erase+0x11d/0x277 [120633.443292] RSP: 0018:ffff8800f7b13a50 EFLAGS: 00010246 [120633.443292] RAX: ffff880022907819 RBX: ffff880022907818 RCX: 0000000000000000 [120633.443292] RDX: ffff8800f7b13a80 RSI: ffff8800f587eb48 RDI: 0000000000000000 [120633.443292] RBP: ffff8800f7b13a60 R08: 0000000000000000 R09: 0000000000000004 [120633.443292] R10: 0000000000000000 R11: ffff8800c4441000 R12: ffff8800f587eb48 [120633.443292] R13: ffff8800f58eaa00 R14: ffff8800f413c000 R15: 0000000000000001 [120633.443292] FS: 00007fbef6e226e0(0000) GS:ffff880009200000(0000) knlGS:0000000000000000 [120633.443292] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b [120633.443292] CR2: 0000000000000000 CR3: 00000000f7c53000 CR4: 00000000000006e0 [120633.443292] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [120633.443292] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [120633.443292] Process ceph-msgr/1 (pid: 3023, threadinfo ffff8800f7b12000, task ffff8800f5858b40) [120633.443292] Stack: [120633.443292] ffff8800f413c000 ffff8800f587e9c0 ffff8800f7b13a80 ffffffffa0098a86 [120633.443292] <0> 00000000000006f1 0000000000000000 ffff8800f7b13af0 ffffffffa009959b [120633.443292] <0> ffff8800f413c000 ffff880022a68400 ffff880022a68400 ffff8800f587e9c0 [120633.443292] Call Trace: [120633.443292] [<ffffffffa0098a86>] __remove_osd+0x4d/0xbc [ceph] [120633.443292] [<ffffffffa009959b>] __map_osds+0x199/0x4fa [ceph] [120633.443292] [<ffffffffa00999f4>] ? __send_request+0xf8/0x186 [ceph] [120633.443292] [<ffffffffa0099beb>] kick_requests+0x169/0x3cb [ceph] [120633.443292] [<ffffffffa009a8c1>] ceph_osdc_handle_map+0x370/0x522 [ceph] Since we're probably screwed anyway if a small kmalloc is failing, don't bother with trying to be clever here. Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Родитель
e80a52d14f
Коммит
c99eb1c726
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@ -615,7 +615,6 @@ static int __map_osds(struct ceph_osd_client *osdc,
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struct ceph_pg pgid;
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int o = -1;
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int err;
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struct ceph_osd *newosd = NULL;
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dout("map_osds %p tid %lld\n", req, req->r_tid);
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err = ceph_calc_object_layout(&reqhead->layout, req->r_oid,
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@ -639,25 +638,15 @@ static int __map_osds(struct ceph_osd_client *osdc,
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if (req->r_osd) {
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__cancel_request(req);
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list_del_init(&req->r_osd_item);
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if (list_empty(&req->r_osd->o_requests)) {
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/* try to re-use r_osd if possible */
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newosd = get_osd(req->r_osd);
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__remove_osd(osdc, newosd);
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}
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req->r_osd = NULL;
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}
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req->r_osd = __lookup_osd(osdc, o);
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if (!req->r_osd && o >= 0) {
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if (newosd) {
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req->r_osd = newosd;
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newosd = NULL;
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} else {
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err = -ENOMEM;
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req->r_osd = create_osd(osdc);
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if (!req->r_osd)
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goto out;
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}
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err = -ENOMEM;
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req->r_osd = create_osd(osdc);
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if (!req->r_osd)
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goto out;
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dout("map_osds osd %p is osd%d\n", req->r_osd, o);
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req->r_osd->o_osd = o;
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@ -674,8 +663,6 @@ static int __map_osds(struct ceph_osd_client *osdc,
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err = 1; /* osd changed */
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out:
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if (newosd)
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put_osd(newosd);
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return err;
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}
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