diff options
| -rw-r--r-- | drivers/md/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/md/dm-bufio.c | 39 | ||||
| -rw-r--r-- | drivers/md/persistent-data/Kconfig | 9 |
3 files changed, 47 insertions, 10 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 7913fdcfc849..1b69359461e9 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -240,6 +240,15 @@ config DM_BUFIO as a cache, holding recently-read blocks in memory and performing delayed writes. +config DM_DEBUG_BLOCK_STACK_TRACING + bool "Keep stack trace of persistent data block lock holders" + depends on STACKTRACE_SUPPORT && DM_BUFIO + select STACKTRACE + ---help--- + Enable this for messages that may help debug problems with the + block manager locking used by thin provisioning and caching. + + If unsure, say N. config DM_BIO_PRISON tristate depends on BLK_DEV_DM diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 7734298bff3c..bccc7e6903e4 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; } @@ -1063,6 +1083,10 @@ 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); @@ -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])); diff --git a/drivers/md/persistent-data/Kconfig b/drivers/md/persistent-data/Kconfig index 78c74bb71ba4..a53cbc928af1 100644 --- a/drivers/md/persistent-data/Kconfig +++ b/drivers/md/persistent-data/Kconfig @@ -7,12 +7,3 @@ config DM_PERSISTENT_DATA Library providing immutable on-disk data structure support for device-mapper targets such as the thin provisioning target. -config DM_DEBUG_BLOCK_STACK_TRACING - bool "Keep stack trace of persistent data block lock holders" - depends on STACKTRACE_SUPPORT && DM_PERSISTENT_DATA - select STACKTRACE - ---help--- - Enable this for messages that may help debug problems with the - block manager locking used by thin provisioning and caching. - - If unsure, say N. |