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-rw-r--r--drivers/md/dm-snap.c295
1 files changed, 174 insertions, 121 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 475514bda9d..14bd1a1815b 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -392,6 +392,8 @@ static void read_snapshot_metadata(struct dm_snapshot *s)
down_write(&s->lock);
s->valid = 0;
up_write(&s->lock);
+
+ dm_table_event(s->table);
}
}
@@ -601,6 +603,11 @@ static void error_bios(struct bio *bio)
}
}
+static inline void error_snapshot_bios(struct pending_exception *pe)
+{
+ error_bios(bio_list_get(&pe->snapshot_bios));
+}
+
static struct bio *__flush_bios(struct pending_exception *pe)
{
/*
@@ -616,6 +623,28 @@ static struct bio *__flush_bios(struct pending_exception *pe)
return NULL;
}
+static void __invalidate_snapshot(struct dm_snapshot *s,
+ struct pending_exception *pe, int err)
+{
+ if (!s->valid)
+ return;
+
+ if (err == -EIO)
+ DMERR("Invalidating snapshot: Error reading/writing.");
+ else if (err == -ENOMEM)
+ DMERR("Invalidating snapshot: Unable to allocate exception.");
+
+ if (pe)
+ remove_exception(&pe->e);
+
+ if (s->store.drop_snapshot)
+ s->store.drop_snapshot(&s->store);
+
+ s->valid = 0;
+
+ dm_table_event(s->table);
+}
+
static void pending_complete(struct pending_exception *pe, int success)
{
struct exception *e;
@@ -623,50 +652,53 @@ static void pending_complete(struct pending_exception *pe, int success)
struct dm_snapshot *s = pe->snap;
struct bio *flush = NULL;
- if (success) {
- e = alloc_exception();
- if (!e) {
- DMWARN("Unable to allocate exception.");
- down_write(&s->lock);
- s->store.drop_snapshot(&s->store);
- s->valid = 0;
- flush = __flush_bios(pe);
- up_write(&s->lock);
-
- error_bios(bio_list_get(&pe->snapshot_bios));
- goto out;
- }
- *e = pe->e;
-
- /*
- * Add a proper exception, and remove the
- * in-flight exception from the list.
- */
+ if (!success) {
+ /* Read/write error - snapshot is unusable */
down_write(&s->lock);
- insert_exception(&s->complete, e);
- remove_exception(&pe->e);
+ __invalidate_snapshot(s, pe, -EIO);
flush = __flush_bios(pe);
-
- /* Submit any pending write bios */
up_write(&s->lock);
- flush_bios(bio_list_get(&pe->snapshot_bios));
- } else {
- /* Read/write error - snapshot is unusable */
+ error_snapshot_bios(pe);
+ goto out;
+ }
+
+ e = alloc_exception();
+ if (!e) {
down_write(&s->lock);
- if (s->valid)
- DMERR("Error reading/writing snapshot");
- s->store.drop_snapshot(&s->store);
- s->valid = 0;
- remove_exception(&pe->e);
+ __invalidate_snapshot(s, pe, -ENOMEM);
flush = __flush_bios(pe);
up_write(&s->lock);
- error_bios(bio_list_get(&pe->snapshot_bios));
+ error_snapshot_bios(pe);
+ goto out;
+ }
+ *e = pe->e;
- dm_table_event(s->table);
+ /*
+ * Add a proper exception, and remove the
+ * in-flight exception from the list.
+ */
+ down_write(&s->lock);
+ if (!s->valid) {
+ flush = __flush_bios(pe);
+ up_write(&s->lock);
+
+ free_exception(e);
+
+ error_snapshot_bios(pe);
+ goto out;
}
+ insert_exception(&s->complete, e);
+ remove_exception(&pe->e);
+ flush = __flush_bios(pe);
+
+ up_write(&s->lock);
+
+ /* Submit any pending write bios */
+ flush_bios(bio_list_get(&pe->snapshot_bios));
+
out:
primary_pe = pe->primary_pe;
@@ -758,39 +790,45 @@ __find_pending_exception(struct dm_snapshot *s, struct bio *bio)
if (e) {
/* cast the exception to a pending exception */
pe = container_of(e, struct pending_exception, e);
+ goto out;
+ }
- } else {
- /*
- * Create a new pending exception, we don't want
- * to hold the lock while we do this.
- */
- up_write(&s->lock);
- pe = alloc_pending_exception();
- down_write(&s->lock);
+ /*
+ * Create a new pending exception, we don't want
+ * to hold the lock while we do this.
+ */
+ up_write(&s->lock);
+ pe = alloc_pending_exception();
+ down_write(&s->lock);
- e = lookup_exception(&s->pending, chunk);
- if (e) {
- free_pending_exception(pe);
- pe = container_of(e, struct pending_exception, e);
- } else {
- pe->e.old_chunk = chunk;
- bio_list_init(&pe->origin_bios);
- bio_list_init(&pe->snapshot_bios);
- pe->primary_pe = NULL;
- atomic_set(&pe->sibling_count, 1);
- pe->snap = s;
- pe->started = 0;
-
- if (s->store.prepare_exception(&s->store, &pe->e)) {
- free_pending_exception(pe);
- s->valid = 0;
- return NULL;
- }
+ if (!s->valid) {
+ free_pending_exception(pe);
+ return NULL;
+ }
- insert_exception(&s->pending, &pe->e);
- }
+ e = lookup_exception(&s->pending, chunk);
+ if (e) {
+ free_pending_exception(pe);
+ pe = container_of(e, struct pending_exception, e);
+ goto out;
}
+ pe->e.old_chunk = chunk;
+ bio_list_init(&pe->origin_bios);
+ bio_list_init(&pe->snapshot_bios);
+ pe->primary_pe = NULL;
+ atomic_set(&pe->sibling_count, 1);
+ pe->snap = s;
+ pe->started = 0;
+
+ if (s->store.prepare_exception(&s->store, &pe->e)) {
+ free_pending_exception(pe);
+ return NULL;
+ }
+
+ insert_exception(&s->pending, &pe->e);
+
+ out:
return pe;
}
@@ -807,13 +845,15 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
{
struct exception *e;
struct dm_snapshot *s = (struct dm_snapshot *) ti->private;
+ int copy_needed = 0;
int r = 1;
chunk_t chunk;
- struct pending_exception *pe;
+ struct pending_exception *pe = NULL;
chunk = sector_to_chunk(s, bio->bi_sector);
/* Full snapshots are not usable */
+ /* To get here the table must be live so s->active is always set. */
if (!s->valid)
return -EIO;
@@ -831,36 +871,41 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
* to copy an exception */
down_write(&s->lock);
+ if (!s->valid) {
+ r = -EIO;
+ goto out_unlock;
+ }
+
/* If the block is already remapped - use that, else remap it */
e = lookup_exception(&s->complete, chunk);
if (e) {
remap_exception(s, e, bio);
- up_write(&s->lock);
-
- } else {
- pe = __find_pending_exception(s, bio);
-
- if (!pe) {
- if (s->store.drop_snapshot)
- s->store.drop_snapshot(&s->store);
- s->valid = 0;
- r = -EIO;
- up_write(&s->lock);
- } else {
- remap_exception(s, &pe->e, bio);
- bio_list_add(&pe->snapshot_bios, bio);
-
- if (!pe->started) {
- /* this is protected by snap->lock */
- pe->started = 1;
- up_write(&s->lock);
- start_copy(pe);
- } else
- up_write(&s->lock);
- r = 0;
- }
+ goto out_unlock;
+ }
+
+ pe = __find_pending_exception(s, bio);
+ if (!pe) {
+ __invalidate_snapshot(s, pe, -ENOMEM);
+ r = -EIO;
+ goto out_unlock;
}
+ remap_exception(s, &pe->e, bio);
+ bio_list_add(&pe->snapshot_bios, bio);
+
+ if (!pe->started) {
+ /* this is protected by snap->lock */
+ pe->started = 1;
+ copy_needed = 1;
+ }
+
+ r = 0;
+
+ out_unlock:
+ up_write(&s->lock);
+
+ if (copy_needed)
+ start_copy(pe);
} else {
/*
* FIXME: this read path scares me because we
@@ -872,6 +917,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
/* Do reads */
down_read(&s->lock);
+ if (!s->valid) {
+ up_read(&s->lock);
+ return -EIO;
+ }
+
/* See if it it has been remapped */
e = lookup_exception(&s->complete, chunk);
if (e)
@@ -948,15 +998,15 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
/* Do all the snapshots on this origin */
list_for_each_entry (snap, snapshots, list) {
+ down_write(&snap->lock);
+
/* Only deal with valid and active snapshots */
if (!snap->valid || !snap->active)
- continue;
+ goto next_snapshot;
/* Nothing to do if writing beyond end of snapshot */
if (bio->bi_sector >= dm_table_get_size(snap->table))
- continue;
-
- down_write(&snap->lock);
+ goto next_snapshot;
/*
* Remember, different snapshots can have
@@ -973,40 +1023,43 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
* won't destroy the primary_pe while we're inside this loop.
*/
e = lookup_exception(&snap->complete, chunk);
- if (!e) {
- pe = __find_pending_exception(snap, bio);
- if (!pe) {
- snap->store.drop_snapshot(&snap->store);
- snap->valid = 0;
-
- } else {
- if (!primary_pe) {
- /*
- * Either every pe here has same
- * primary_pe or none has one yet.
- */
- if (pe->primary_pe)
- primary_pe = pe->primary_pe;
- else {
- primary_pe = pe;
- first = 1;
- }
-
- bio_list_add(&primary_pe->origin_bios,
- bio);
- r = 0;
- }
- if (!pe->primary_pe) {
- atomic_inc(&primary_pe->sibling_count);
- pe->primary_pe = primary_pe;
- }
- if (!pe->started) {
- pe->started = 1;
- list_add_tail(&pe->list, &pe_queue);
- }
+ if (e)
+ goto next_snapshot;
+
+ pe = __find_pending_exception(snap, bio);
+ if (!pe) {
+ __invalidate_snapshot(snap, pe, ENOMEM);
+ goto next_snapshot;
+ }
+
+ if (!primary_pe) {
+ /*
+ * Either every pe here has same
+ * primary_pe or none has one yet.
+ */
+ if (pe->primary_pe)
+ primary_pe = pe->primary_pe;
+ else {
+ primary_pe = pe;
+ first = 1;
}
+
+ bio_list_add(&primary_pe->origin_bios, bio);
+
+ r = 0;
+ }
+
+ if (!pe->primary_pe) {
+ atomic_inc(&primary_pe->sibling_count);
+ pe->primary_pe = primary_pe;
+ }
+
+ if (!pe->started) {
+ pe->started = 1;
+ list_add_tail(&pe->list, &pe_queue);
}
+ next_snapshot:
up_write(&snap->lock);
}
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