On Sat, 7 Feb 2009, Jacky Kim wrote:
> Hi
>
> I create PV over a RAID set, and its stripe size is 64KB.
> The chunk size of the snapshot is 4KB, is it too small? then what size
> is better?
It means that there is another bug besides the one I have just fixed :-(
So try another patch (on the top of them all) with even more debug points.
Mikulas
> I test with kernel 2.6.28.2, and get the follow message:
>
> [ 531.209879] ------------[ cut here ]------------
> [ 531.209884] kernel BUG at drivers/md/dm-exception-store.c:715!
> [ 531.209886] invalid opcode: 0000 [#1] SMP
> [ 531.209888] last sysfs file: /sys/devices/virtual/block/dm-11/dev
> [ 531.209890] Modules linked in: iscsi_trgt arcmsr bonding e1000
> [ 531.209893]
> [ 531.209896] Pid: 8241, comm: kcopyd Not tainted (2.6.28.2-dm #6) S5000PSL
> [ 531.209898] EIP: 0060:[<c03c7dc2>] EFLAGS: 00010246 CPU: 1
> [ 531.209903] EIP is at persistent_commit+0x222/0x280
> [ 531.209905] EAX: f5385708 EBX: 00000006 ECX: fabab030 EDX: 00000000
> [ 531.209906] ESI: 00000000 EDI: ef35f840 EBP: 00000075 ESP: f4fc3f14
> [ 531.209908] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
> [ 531.209910] Process kcopyd (pid: 8241, ti=f4fc2000 task=f4f16800 task.ti=f4fc2000)
> [ 531.209911] Stack:
> [ 531.209912] c03c6710 000165da 00000000 f5015348 f482f2c0 00000000 c03c66b0 c03c66e3
> [ 531.209916] f5015348 f487f160 ef52e1c0 c03c13f8 f4f16800 f5015348 00000000 f487f160
> [ 531.209919] f487f164 ef52e1fc ef52e200 c03c119c c03c13a0 ef52e1c0 00000001 ef52e1ec
> [ 531.209923] Call Trace:
> [ 531.209925] [<c03c6710>] commit_callback+0x0/0x30
> [ 531.209928] [<c03c66b0>] copy_callback+0x0/0x60
> [ 531.209935] [<c03c66e3>] copy_callback+0x33/0x60
> [ 531.209938] [<c03c13f8>] run_complete_job+0x58/0xa0
> [ 531.209945] [<c03c119c>] process_jobs+0x4c/0xe0
> [ 531.209947] [<c03c13a0>] run_complete_job+0x0/0xa0
> [ 531.209950] [<c03c1230>] do_work+0x0/0x50
> [ 531.209951] [<c03c124e>] do_work+0x1e/0x50
> [ 531.209953] [<c012ef32>] run_workqueue+0x72/0x100
> [ 531.209962] [<c0132570>] prepare_to_wait+0x20/0x60
> [ 531.209965] [<c012f840>] worker_thread+0x0/0xb0
> [ 531.209972] [<c012f8b9>] worker_thread+0x79/0xb0
> [ 531.209974] [<c01323d0>] autoremove_wake_function+0x0/0x50
> [ 531.209976] [<c012f840>] worker_thread+0x0/0xb0
> [ 531.209978] [<c01320d2>] kthread+0x42/0x70
> [ 531.209980] [<c0132090>] kthread+0x0/0x70
> [ 531.209982] [<c0103eff>] kernel_thread_helper+0x7/0x18
> [ 531.209984] Code: 0b eb fe 0f 0b eb fe ba 01 00 00 00 89 f8 e8 d6 f8 ff ff 85 c0 0f 84 18 ff ff ff c7 47 08 00 00 00 00 e9 0c ff ff ff 0f 0b eb fe <0f> 0b eb fe 0f 0b eb fe 0f 0b eb fe 0f 0b eb fe 0f 0b eb fe 83
> [ 531.210006] EIP: [<c03c7dc2>] persistent_commit+0x222/0x280 SS:ESP 0068:f4fc3f14
> [ 531.210010] ---[ end trace fc1bc1bb8712a6ff ]---
> [ 556.042136] iscsi_trgt: Logical Unit Reset (05) issued on tid:1 lun:0 by sid:281475899523136 (Function Complete)
>
> Jacky
> .
---
drivers/md/dm-exception-store.c | 7 +++++++
drivers/md/dm-kcopyd.c | 34 +++++++++++++++++++++++++++++++++-
drivers/md/dm-snap.c | 4 ++++
3 files changed, 44 insertions(+), 1 deletion(-)
Index: linux-2.6.28-clean/drivers/md/dm-exception-store.c
===================================================================
--- linux-2.6.28-clean.orig/drivers/md/dm-exception-store.c 2009-02-09 08:43:40.000000000 +0100
+++ linux-2.6.28-clean/drivers/md/dm-exception-store.c 2009-02-09 08:43:46.000000000 +0100
@@ -645,6 +645,13 @@ static void persistent_commit(struct exc
de.new_chunk = e->new_chunk;
write_exception(ps, ps->current_committed++, &de);
+ for (i = 0; i < ps->callback_count; i++) {
+ cb = ps->callbacks + i;
+ pe = cb->context;
+ BUG_ON(pe->e.hash_list.next == LIST_POISON1);
+ BUG_ON(pe->e.hash_list.prev == LIST_POISON2);
+ BUG_ON(pe == callback_context);
+ }
/*
* Add the callback to the back of the array. This code
* is the only place where the callback array is
Index: linux-2.6.28-clean/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.28-clean.orig/drivers/md/dm-snap.c 2009-02-09 08:43:40.000000000 +0100
+++ linux-2.6.28-clean/drivers/md/dm-snap.c 2009-02-09 08:43:46.000000000 +0100
@@ -979,6 +979,10 @@ static void start_copy(struct dm_snap_pe
struct dm_io_region src, dest;
struct block_device *bdev = s->origin->bdev;
sector_t dev_size;
+ BUG_ON(!pe->started);
+ BUG_ON(pe->started == 2);
+ BUG_ON(pe->started != 1);
+ pe->started = 2;
dev_size = get_dev_size(bdev);
Index: linux-2.6.28-clean/drivers/md/dm-kcopyd.c
===================================================================
--- linux-2.6.28-clean.orig/drivers/md/dm-kcopyd.c 2009-02-09 08:43:40.000000000 +0100
+++ linux-2.6.28-clean/drivers/md/dm-kcopyd.c 2009-02-09 08:44:47.000000000 +0100
@@ -60,6 +60,7 @@ struct dm_kcopyd_client {
struct list_head complete_jobs;
struct list_head io_jobs;
struct list_head pages_jobs;
+ struct list_head all_jobs;
};
static void wake(struct dm_kcopyd_client *kc)
@@ -209,6 +210,8 @@ struct kcopyd_job {
dm_kcopyd_notify_fn fn;
void *context;
+ struct list_head list_all;
+
/*
* These fields are only used if the job has been split
* into more manageable parts.
@@ -280,6 +283,9 @@ static void push_head(struct list_head *
spin_unlock_irqrestore(&kc->job_lock, flags);
}
+static void segment_complete(int read_err, unsigned long write_err,
+ void *context);
+
/*
* These three functions process 1 item from the corresponding
* job list.
@@ -291,6 +297,8 @@ static void push_head(struct list_head *
*/
static int run_complete_job(struct kcopyd_job *job)
{
+ struct kcopyd_job *jobb;
+ unsigned long flags;
void *context = job->context;
int read_err = job->read_err;
unsigned long write_err = job->write_err;
@@ -299,6 +307,18 @@ static int run_complete_job(struct kcopy
if (job->pages)
kcopyd_put_pages(kc, job->pages);
+
+ if (fn != segment_complete) {
+ spin_lock_irqsave(&kc->job_lock, flags);
+ list_del(&job->list_all);
+ spin_unlock_irqrestore(&kc->job_lock, flags);
+
+ spin_lock_irqsave(&kc->job_lock, flags);
+ list_for_each_entry(jobb, &kc->all_jobs, list_all)
+ BUG_ON(jobb->fn == fn && jobb->context == context);
+ spin_unlock_irqrestore(&kc->job_lock, flags);
+ }
+
mempool_free(job, kc->job_pool);
fn(read_err, write_err, context);
@@ -535,7 +555,8 @@ int dm_kcopyd_copy(struct dm_kcopyd_clie
unsigned int num_dests, struct dm_io_region *dests,
unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
{
- struct kcopyd_job *job;
+ struct kcopyd_job *job, *jobb;
+ unsigned long fflags;
/*
* Allocate a new job.
@@ -563,6 +584,15 @@ int dm_kcopyd_copy(struct dm_kcopyd_clie
job->fn = fn;
job->context = context;
+ spin_lock_irqsave(&kc->job_lock, fflags);
+ list_for_each_entry(jobb, &kc->all_jobs, list_all)
+ BUG_ON(jobb->fn == fn && jobb->context == context);
+ spin_unlock_irqrestore(&kc->job_lock, fflags);
+
+ spin_lock_irqsave(&kc->job_lock, fflags);
+ list_add_tail(&job->list_all, &kc->all_jobs);
+ spin_unlock_irqrestore(&kc->job_lock, fflags);
+
if (job->source.count < SUB_JOB_SIZE)
dispatch_job(job);
@@ -603,6 +633,7 @@ int dm_kcopyd_client_create(unsigned int
spin_lock_init(&kc->lock);
spin_lock_init(&kc->job_lock);
+ INIT_LIST_HEAD(&kc->all_jobs);
INIT_LIST_HEAD(&kc->complete_jobs);
INIT_LIST_HEAD(&kc->io_jobs);
INIT_LIST_HEAD(&kc->pages_jobs);
@@ -652,6 +683,7 @@ void dm_kcopyd_client_destroy(struct dm_
/* Wait for completion of all jobs submitted by this client. */
wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs));
+ BUG_ON(!list_empty(&kc->all_jobs));
BUG_ON(!list_empty(&kc->complete_jobs));
BUG_ON(!list_empty(&kc->io_jobs));
BUG_ON(!list_empty(&kc->pages_jobs));
--
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