Sorry for not responding... earlier.
I didn't need the test case, because the more I looked at it, the more
obvious it became. I also quickly discovered the compile bug, and
mirror_map uses bio_ro_region now in newer kernels.
I've also check to make sure that it doesn't screw anything up when
fault tolerance is included (see http://www.brassow.com/mirroring). We
had to check to ensure that if bio_map was called (which alters the bio
and takes off the ti->begin) that a later function would not then call
the updated bio_to_region - effectively subtracting off ti->begin
twice.
thanks for the update though,
brassow
On May 18, 2006, at 8:17 PM, Neil Brown wrote:
On Tuesday May 9, Jonathan E Brassow wrote:
It looks reasonable at first glance, but I have to think about it
more. Do you have a test case that I can reproduce with?
Not really... The customer does, but I don't have precise details.
I think is several drives, with several lvs across them, and active
NFS activity on these.
In this situation 'pvmove' everything off a device which contains a
non-initial section of at least one of the lvs. The active traffic on
the filesystem in an important part of the test case I think.
I have since found that not only didn't the original patch compile,
but it wasn't complete either.
The mirror_map function sets map_context->ll to a value which is
effectively the same as bio_to_region. As I changed bio_to_region, I
need to change that assignment to.
This is the current patch. Note that the declaration of two structures
needed to be moved up for it to compile.
NeilBrown
Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./drivers/md/dm-raid1.c | 63
++++++++++++++++++++++++------------------------
1 file changed, 32 insertions(+), 31 deletions(-)
diff ./drivers/md/dm-raid1.c~current~ ./drivers/md/dm-raid1.c
--- ./drivers/md/dm-raid1.c~current~ 2006-05-12 14:28:37.000000000
+1000
+++ ./drivers/md/dm-raid1.c 2006-05-19 11:15:58.000000000 +1000
@@ -106,12 +106,42 @@ struct region {
struct bio_list delayed_bios;
};
+
+/*-----------------------------------------------------------------
+ * Mirror set structures.
+ *---------------------------------------------------------------*/
+struct mirror {
+ atomic_t error_count;
+ struct dm_dev *dev;
+ sector_t offset;
+};
+
+struct mirror_set {
+ struct dm_target *ti;
+ struct list_head list;
+ struct region_hash rh;
+ struct kcopyd_client *kcopyd_client;
+
+ spinlock_t lock; /* protects the next two lists */
+ struct bio_list reads;
+ struct bio_list writes;
+
+ /* recovery */
+ region_t nr_regions;
+ int in_sync;
+
+ struct mirror *default_mirror; /* Default mirror */
+
+ unsigned int nr_mirrors;
+ struct mirror mirror[0];
+};
+
/*
* Conversion fns
*/
static inline region_t bio_to_region(struct region_hash *rh, struct
bio *bio)
{
- return bio->bi_sector >> rh->region_shift;
+ return (bio->bi_sector - rh->ms->ti->begin) >> rh->region_shift;
}
static inline sector_t region_to_sector(struct region_hash *rh,
region_t region)
@@ -539,35 +569,6 @@ static void rh_start_recovery(struct reg
wake();
}
-/*-----------------------------------------------------------------
- * Mirror set structures.
- *---------------------------------------------------------------*/
-struct mirror {
- atomic_t error_count;
- struct dm_dev *dev;
- sector_t offset;
-};
-
-struct mirror_set {
- struct dm_target *ti;
- struct list_head list;
- struct region_hash rh;
- struct kcopyd_client *kcopyd_client;
-
- spinlock_t lock; /* protects the next two lists */
- struct bio_list reads;
- struct bio_list writes;
-
- /* recovery */
- region_t nr_regions;
- int in_sync;
-
- struct mirror *default_mirror; /* Default mirror */
-
- unsigned int nr_mirrors;
- struct mirror mirror[0];
-};
-
/*
* Every mirror should look like this one.
*/
@@ -1113,7 +1114,7 @@ static int mirror_map(struct dm_target *
struct mirror *m;
struct mirror_set *ms = ti->private;
- map_context->ll = bio->bi_sector >> ms->rh.region_shift;
+ map_context->ll = bio_to_region(&ms->rh, bio);
if (rw == WRITE) {
queue_bio(ms, bio, rw);
--
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