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Commit | Line | Data |
---|---|---|
00e5a55c BS |
1 | From: Hannes Reinecke <hare@suse.de> |
2 | Subject: Handle I/O on stopped queues correctly | |
3 | References: bnc#458393 | |
4 | ||
5 | The current multipath infrastructure has several issues when I/O is | |
6 | submitted during a table reload. | |
7 | The make_request_fn must not fail if no table is present, as I/O | |
8 | will be queued properly in the request queue. But on the other hand | |
9 | we should not submit queued I/Os if the queue of the underlying | |
10 | device is stopped; that queue is undergoing reconfiguration | |
11 | time and may be in all sort of states. | |
12 | ||
13 | And while we're at it, we should detach any hardware handler | |
14 | if the multipath table doesn't specify one. | |
15 | ||
16 | Signed-off-by: Hannes Reinecke <hare@suse.de> | |
17 | ||
18 | Index: linux-2.6.27/drivers/md/dm-mpath.c | |
19 | =================================================================== | |
20 | --- linux-2.6.27.orig/drivers/md/dm-mpath.c | |
21 | +++ linux-2.6.27/drivers/md/dm-mpath.c | |
22 | @@ -159,9 +159,7 @@ static struct priority_group *alloc_prio | |
23 | ||
24 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
25 | { | |
26 | - unsigned long flags; | |
27 | struct pgpath *pgpath, *tmp; | |
28 | - struct multipath *m = ti->private; | |
29 | ||
30 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
31 | list_del(&pgpath->list); | |
32 | @@ -436,8 +434,8 @@ static void process_queued_ios(struct wo | |
33 | { | |
34 | struct multipath *m = | |
35 | container_of(work, struct multipath, process_queued_ios); | |
36 | - struct pgpath *pgpath = NULL, *tmp; | |
37 | - unsigned must_queue = 1; | |
38 | + struct pgpath *pgpath = NULL, *tmp; | |
39 | + unsigned must_queue = 1; | |
40 | unsigned long flags; | |
41 | ||
42 | spin_lock_irqsave(&m->lock, flags); | |
43 | @@ -450,6 +448,12 @@ static void process_queued_ios(struct wo | |
44 | ||
45 | pgpath = m->current_pgpath; | |
46 | ||
47 | + if (pgpath) { | |
48 | + struct block_device *bdev = pgpath->path.dev->bdev; | |
49 | + if (unlikely(blk_queue_stopped(bdev_get_queue(bdev)))) | |
50 | + goto out; | |
51 | + } | |
52 | + | |
53 | if ((pgpath && !m->queue_io) || | |
54 | (!pgpath && !m->queue_if_no_path)) | |
55 | must_queue = 0; | |
56 | @@ -619,22 +623,24 @@ static struct pgpath *parse_path(struct | |
57 | memcpy(p->path.pdev, p->path.dev->name, 16); | |
58 | } | |
59 | ||
60 | - if (m->hw_handler_name && p->path.dev) { | |
61 | + if (p->path.dev) { | |
62 | struct request_queue *q = bdev_get_queue(p->path.dev->bdev); | |
63 | ||
64 | - r = scsi_dh_attach(q, m->hw_handler_name); | |
65 | - if (r == -EBUSY) { | |
66 | - /* | |
67 | - * Already attached to different hw_handler, | |
68 | - * try to reattach with correct one. | |
69 | - */ | |
70 | - scsi_dh_detach(q); | |
71 | + if (m->hw_handler_name) { | |
72 | r = scsi_dh_attach(q, m->hw_handler_name); | |
73 | - } | |
74 | - if (r < 0) { | |
75 | - ti->error = "error attaching hardware handler"; | |
76 | - dm_put_device(ti, p->path.dev); | |
77 | - goto bad; | |
78 | + if (r == -EBUSY) { | |
79 | + /* | |
80 | + * Already attached to different hw_handler, | |
81 | + * try to reattach with correct one. | |
82 | + */ | |
83 | + scsi_dh_detach(q); | |
84 | + r = scsi_dh_attach(q, m->hw_handler_name); | |
85 | + } | |
86 | + if (r < 0) { | |
87 | + ti->error = "error attaching hardware handler"; | |
88 | + dm_put_device(ti, p->path.dev); | |
89 | + goto bad; | |
90 | + } | |
91 | } | |
92 | } | |
93 | ||
94 | @@ -644,6 +653,11 @@ static struct pgpath *parse_path(struct | |
95 | goto bad; | |
96 | } | |
97 | ||
98 | + if (!p->is_active) { | |
99 | + ps->type->fail_path(ps, &p->path); | |
100 | + p->fail_count++; | |
101 | + m->nr_valid_paths--; | |
102 | + } | |
103 | return p; | |
104 | ||
105 | bad: | |
106 | Index: linux-2.6.27/drivers/md/dm.c | |
107 | =================================================================== | |
108 | --- linux-2.6.27.orig/drivers/md/dm.c | |
109 | +++ linux-2.6.27/drivers/md/dm.c | |
110 | @@ -1304,7 +1304,11 @@ static int dm_make_request(struct reques | |
111 | return 0; | |
112 | } | |
113 | ||
114 | - if (unlikely(!md->map)) { | |
115 | + /* | |
116 | + * Submitting to a stopped queue with no map is okay; | |
117 | + * might happen during reconfiguration. | |
118 | + */ | |
119 | + if (unlikely(!md->map) && !blk_queue_stopped(q)) { | |
120 | bio_endio(bio, -EIO); | |
121 | return 0; | |
122 | } |