diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 59f82939e634e9f81c30c75c98a71577385af44b..1bc822b5a4c090f83054c6d41c605e39f5fe16d6 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6813,6 +6813,64 @@ int btrfs_read_sys_array(struct btrfs_fs_info *fs_info) return -EIO; } +/* + * Check if all chunks in the fs are OK for read-write degraded mount + * + * Return true if all chunks meet the minimal RW mount requirements. + * Return false if any chunk doesn't meet the minimal RW mount requirements. + */ +bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info) +{ + struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree; + struct extent_map *em; + u64 next_start = 0; + bool ret = true; + + read_lock(&map_tree->map_tree.lock); + em = lookup_extent_mapping(&map_tree->map_tree, 0, (u64)-1); + read_unlock(&map_tree->map_tree.lock); + /* No chunk at all? Return false anyway */ + if (!em) { + ret = false; + goto out; + } + while (em) { + struct map_lookup *map; + int missing = 0; + int max_tolerated; + int i; + + map = em->map_lookup; + max_tolerated = + btrfs_get_num_tolerated_disk_barrier_failures( + map->type); + for (i = 0; i < map->num_stripes; i++) { + struct btrfs_device *dev = map->stripes[i].dev; + + if (!dev || !dev->bdev || dev->missing || + dev->last_flush_error) + missing++; + } + if (missing > max_tolerated) { + btrfs_warn(fs_info, + "chunk %llu missing %d devices, max tolerance is %d for writeable mount", + em->start, missing, max_tolerated); + free_extent_map(em); + ret = false; + goto out; + } + next_start = extent_map_end(em); + free_extent_map(em); + + read_lock(&map_tree->map_tree.lock); + em = lookup_extent_mapping(&map_tree->map_tree, next_start, + (u64)(-1) - next_start); + read_unlock(&map_tree->map_tree.lock); + } +out: + return ret; +} + int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info) { struct btrfs_root *root = fs_info->chunk_root; diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 6f45fd60d15a92d7aea7a5711bb365a201cb09f9..5824cdc0b3fca3237426200fed754b79ef12b51f 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -543,4 +543,6 @@ struct list_head *btrfs_get_fs_uuids(void); void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info); void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info); +bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info); + #endif