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path: root/drivers/md/dm-bufio.c
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Diffstat (limited to 'drivers/md/dm-bufio.c')
-rw-r--r--drivers/md/dm-bufio.c44
1 files changed, 40 insertions, 4 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 2dd33085b331..6b832e06580d 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -16,6 +16,7 @@
#include <linux/shrinker.h>
#include <linux/module.h>
#include <linux/rbtree.h>
+#include <linux/stacktrace.h>
#define DM_MSG_PREFIX "bufio"
@@ -149,6 +150,11 @@ struct dm_buffer {
struct list_head write_list;
struct bio bio;
struct bio_vec bio_vec[DM_BUFIO_INLINE_VECS];
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+#define MAX_STACK 10
+ struct stack_trace stack_trace;
+ unsigned long stack_entries[MAX_STACK];
+#endif
};
/*----------------------------------------------------------------*/
@@ -253,6 +259,17 @@ static LIST_HEAD(dm_bufio_all_clients);
*/
static DEFINE_MUTEX(dm_bufio_clients_lock);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+static void buffer_record_stack(struct dm_buffer *b)
+{
+ b->stack_trace.nr_entries = 0;
+ b->stack_trace.max_entries = MAX_STACK;
+ b->stack_trace.entries = b->stack_entries;
+ b->stack_trace.skip = 2;
+ save_stack_trace(&b->stack_trace);
+}
+#endif
+
/*----------------------------------------------------------------
* A red/black tree acts as an index for all the buffers.
*--------------------------------------------------------------*/
@@ -454,6 +471,9 @@ static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask)
adjust_total_allocated(b->data_mode, (long)c->block_size);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ memset(&b->stack_trace, 0, sizeof(b->stack_trace));
+#endif
return b;
}
@@ -1063,12 +1083,16 @@ static void *new_read(struct dm_bufio_client *c, sector_t block,
dm_bufio_lock(c);
b = __bufio_new(c, block, nf, &need_submit, &write_list);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ if (b && b->hold_count == 1)
+ buffer_record_stack(b);
+#endif
dm_bufio_unlock(c);
__flush_write_list(&write_list);
if (!b)
- return b;
+ return NULL;
if (need_submit)
submit_io(b, READ, b->block, read_endio);
@@ -1462,6 +1486,7 @@ static void drop_buffers(struct dm_bufio_client *c)
{
struct dm_buffer *b;
int i;
+ bool warned = false;
BUG_ON(dm_bufio_in_request());
@@ -1476,9 +1501,21 @@ static void drop_buffers(struct dm_bufio_client *c)
__free_buffer_wake(b);
for (i = 0; i < LIST_SIZE; i++)
- list_for_each_entry(b, &c->lru[i], lru_list)
+ list_for_each_entry(b, &c->lru[i], lru_list) {
+ WARN_ON(!warned);
+ warned = true;
DMERR("leaked buffer %llx, hold count %u, list %d",
(unsigned long long)b->block, b->hold_count, i);
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ print_stack_trace(&b->stack_trace, 1);
+ b->hold_count = 0; /* mark unclaimed to avoid BUG_ON below */
+#endif
+ }
+
+#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
+ while ((b = __get_unclaimed_buffer(c)))
+ __free_buffer_wake(b);
+#endif
for (i = 0; i < LIST_SIZE; i++)
BUG_ON(!list_empty(&c->lru[i]));
@@ -1891,8 +1928,7 @@ static void __exit dm_bufio_exit(void)
bug = 1;
}
- if (bug)
- BUG();
+ BUG_ON(bug);
}
module_init(dm_bufio_init)