diff options
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-pcache/cache_segment.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/md/dm-pcache/cache_segment.c b/drivers/md/dm-pcache/cache_segment.c index 9d92e2b067ed..c698ebbc626d 100644 --- a/drivers/md/dm-pcache/cache_segment.c +++ b/drivers/md/dm-pcache/cache_segment.c @@ -243,8 +243,16 @@ struct pcache_cache_segment *get_cache_segment(struct pcache_cache *cache) spin_lock(&cache->seg_map_lock); again: - seg_id = find_next_zero_bit(cache->seg_map, cache->n_segs, cache->last_cache_seg); - if (seg_id == cache->n_segs) { + /* + * Only allocate initialized segments. cache_segs_init() initializes + * cache_info.n_segs of the cache->n_segs device segments; a forged + * smaller cache_info.n_segs leaves the rest as zeroed structs whose data + * pointer is NULL. Bounding the search to cache_info.n_segs keeps such a + * segment from reaching cache_kset_close(), which writes through it. + */ + seg_id = find_next_zero_bit(cache->seg_map, cache->cache_info.n_segs, + cache->last_cache_seg); + if (seg_id == cache->cache_info.n_segs) { /* reset the hint of ->last_cache_seg and retry */ if (cache->last_cache_seg) { cache->last_cache_seg = 0; |