-stable review patch. If anyone has any objections, please let us know.
------------------
From: Alasdair G Kergon <[email protected]>
Before removing a snapshot, wait for the completion of any kcopyd jobs using
it.
Do this by maintaining a count (nr_jobs) of how many outstanding jobs each
kcopyd_client has.
The snapshot destructor first unregisters the snapshot so that no new kcopyd
jobs (created by writes to the origin) will reference that particular
snapshot. kcopyd_client_destroy() is now run next to wait for the completion
of any outstanding jobs before the snapshot exception structures (that those
jobs reference) are freed.
Signed-off-by: Alasdair G Kergon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/md/dm-snap.c | 6 +++++-
drivers/md/kcopyd.c | 17 ++++++++++++++++-
2 files changed, 21 insertions(+), 2 deletions(-)
--- linux-2.6.16.11.orig/drivers/md/dm-snap.c
+++ linux-2.6.16.11/drivers/md/dm-snap.c
@@ -542,8 +542,12 @@ static void snapshot_dtr(struct dm_targe
{
struct dm_snapshot *s = (struct dm_snapshot *) ti->private;
+ /* Prevent further origin writes from using this snapshot. */
+ /* After this returns there can be no new kcopyd jobs. */
unregister_snapshot(s);
+ kcopyd_client_destroy(s->kcopyd_client);
+
exit_exception_table(&s->pending, pending_cache);
exit_exception_table(&s->complete, exception_cache);
@@ -552,7 +556,7 @@ static void snapshot_dtr(struct dm_targe
dm_put_device(ti, s->origin);
dm_put_device(ti, s->cow);
- kcopyd_client_destroy(s->kcopyd_client);
+
kfree(s);
}
--- linux-2.6.16.11.orig/drivers/md/kcopyd.c
+++ linux-2.6.16.11/drivers/md/kcopyd.c
@@ -44,6 +44,9 @@ struct kcopyd_client {
struct page_list *pages;
unsigned int nr_pages;
unsigned int nr_free_pages;
+
+ wait_queue_head_t destroyq;
+ atomic_t nr_jobs;
};
static struct page_list *alloc_pl(void)
@@ -293,10 +296,15 @@ static int run_complete_job(struct kcopy
int read_err = job->read_err;
unsigned int write_err = job->write_err;
kcopyd_notify_fn fn = job->fn;
+ struct kcopyd_client *kc = job->kc;
- kcopyd_put_pages(job->kc, job->pages);
+ kcopyd_put_pages(kc, job->pages);
mempool_free(job, _job_pool);
fn(read_err, write_err, context);
+
+ if (atomic_dec_and_test(&kc->nr_jobs))
+ wake_up(&kc->destroyq);
+
return 0;
}
@@ -431,6 +439,7 @@ static void do_work(void *ignored)
*/
static void dispatch_job(struct kcopyd_job *job)
{
+ atomic_inc(&job->kc->nr_jobs);
push(&_pages_jobs, job);
wake();
}
@@ -670,6 +679,9 @@ int kcopyd_client_create(unsigned int nr
return r;
}
+ init_waitqueue_head(&kc->destroyq);
+ atomic_set(&kc->nr_jobs, 0);
+
client_add(kc);
*result = kc;
return 0;
@@ -677,6 +689,9 @@ int kcopyd_client_create(unsigned int nr
void kcopyd_client_destroy(struct kcopyd_client *kc)
{
+ /* Wait for completion of all jobs submitted by this client. */
+ wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs));
+
dm_io_put(kc->nr_pages);
client_free_pages(kc);
client_del(kc);
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
