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path: root/drivers/md/dm-snap.c
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Diffstat (limited to 'drivers/md/dm-snap.c')
-rw-r--r--drivers/md/dm-snap.c49
1 files changed, 25 insertions, 24 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 7c82d3ccc..c06b74e91 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -63,6 +63,13 @@ struct dm_snapshot {
*/
int valid;
+ /*
+ * The snapshot overflowed because of a write to the snapshot device.
+ * We don't have to invalidate the snapshot in this case, but we need
+ * to prevent further writes.
+ */
+ int snapshot_overflowed;
+
/* Origin writes don't trigger exceptions until this is set */
int active;
@@ -1091,7 +1098,7 @@ static void stop_merge(struct dm_snapshot *s)
}
/*
- * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size>
+ * Construct a snapshot mapping: <origin_dev> <COW-dev> <p|po|n> <chunk-size>
*/
static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
@@ -1152,6 +1159,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
s->ti = ti;
s->valid = 1;
+ s->snapshot_overflowed = 0;
s->active = 0;
atomic_set(&s->pending_exceptions_count, 0);
s->exception_start_sequence = 0;
@@ -1294,6 +1302,7 @@ static void __handover_exceptions(struct dm_snapshot *snap_src,
u.store_swap = snap_dest->store;
snap_dest->store = snap_src->store;
+ snap_dest->store->userspace_supports_overflow = u.store_swap->userspace_supports_overflow;
snap_src->store = u.store_swap;
snap_dest->store->snap = snap_dest;
@@ -1301,6 +1310,7 @@ static void __handover_exceptions(struct dm_snapshot *snap_src,
snap_dest->ti->max_io_len = snap_dest->store->chunk_size;
snap_dest->valid = snap_src->valid;
+ snap_dest->snapshot_overflowed = snap_src->snapshot_overflowed;
/*
* Set source invalid to ensure it receives no further I/O.
@@ -1490,7 +1500,7 @@ out:
error_bios(snapshot_bios);
} else {
if (full_bio)
- bio_endio(full_bio, 0);
+ bio_endio(full_bio);
flush_bios(snapshot_bios);
}
@@ -1580,11 +1590,11 @@ static void start_copy(struct dm_snap_pending_exception *pe)
dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, copy_callback, pe);
}
-static void full_bio_end_io(struct bio *bio, int error)
+static void full_bio_end_io(struct bio *bio)
{
void *callback_data = bio->bi_private;
- dm_kcopyd_do_callback(callback_data, 0, error ? 1 : 0);
+ dm_kcopyd_do_callback(callback_data, 0, bio->bi_error ? 1 : 0);
}
static void start_full_bio(struct dm_snap_pending_exception *pe,
@@ -1691,7 +1701,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
* to copy an exception */
down_write(&s->lock);
- if (!s->valid) {
+ if (!s->valid || (unlikely(s->snapshot_overflowed) && bio_rw(bio) == WRITE)) {
r = -EIO;
goto out_unlock;
}
@@ -1715,7 +1725,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
pe = alloc_pending_exception(s);
down_write(&s->lock);
- if (!s->valid) {
+ if (!s->valid || s->snapshot_overflowed) {
free_pending_exception(pe);
r = -EIO;
goto out_unlock;
@@ -1730,7 +1740,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
pe = __find_pending_exception(s, pe, chunk);
if (!pe) {
- __invalidate_snapshot(s, -ENOMEM);
+ if (s->store->userspace_supports_overflow) {
+ s->snapshot_overflowed = 1;
+ DMERR("Snapshot overflowed: Unable to allocate exception.");
+ } else
+ __invalidate_snapshot(s, -ENOMEM);
r = -EIO;
goto out_unlock;
}
@@ -1990,6 +2004,8 @@ static void snapshot_status(struct dm_target *ti, status_type_t type,
DMEMIT("Invalid");
else if (snap->merge_failed)
DMEMIT("Merge failed");
+ else if (snap->snapshot_overflowed)
+ DMEMIT("Overflow");
else {
if (snap->store->type->usage) {
sector_t total_sectors, sectors_allocated,
@@ -2330,20 +2346,6 @@ static void origin_status(struct dm_target *ti, status_type_t type,
}
}
-static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct dm_origin *o = ti->private;
- struct request_queue *q = bdev_get_queue(o->dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = o->dev->bdev;
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int origin_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
@@ -2362,13 +2364,12 @@ static struct target_type origin_target = {
.resume = origin_resume,
.postsuspend = origin_postsuspend,
.status = origin_status,
- .merge = origin_merge,
.iterate_devices = origin_iterate_devices,
};
static struct target_type snapshot_target = {
.name = "snapshot",
- .version = {1, 13, 0},
+ .version = {1, 15, 0},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,
@@ -2382,7 +2383,7 @@ static struct target_type snapshot_target = {
static struct target_type merge_target = {
.name = dm_snapshot_merge_target_name,
- .version = {1, 3, 0},
+ .version = {1, 4, 0},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,