diff options
Diffstat (limited to 'fs/btrfs/volumes.c')
| -rw-r--r-- | fs/btrfs/volumes.c | 105 |
1 files changed, 90 insertions, 15 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 4075b1b95105..81edabb2524d 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -216,7 +216,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, * * global::fs_devs - add, remove, updates to the global list * - * does not protect: manipulation of the fs_devices::devices list! + * does not protect: manipulation of the fs_devices::devices list in general + * but in mount context it could be used to exclude list modifications by eg. + * scan ioctl * * btrfs_device::name - renames (write side), read is RCU * @@ -229,6 +231,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, * may be used to exclude some operations from running concurrently without any * modifications to the list (see write_all_supers) * + * Is not required at mount and close times, because our device list is + * protected by the uuid_mutex at that point. + * * balance_mutex * ------------- * protects balance structures (status, state) and context accessed from @@ -786,6 +791,11 @@ static int btrfs_free_stale_devices(const char *path, return ret; } +/* + * This is only used on mount, and we are protected from competing things + * messing with our fs_devices by the uuid_mutex, thus we do not need the + * fs_devices->device_list_mutex here. + */ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices, struct btrfs_device *device, fmode_t flags, void *holder) @@ -889,17 +899,54 @@ static struct btrfs_fs_devices *find_fsid_changed( /* * Handles the case where scanned device is part of an fs that had * multiple successful changes of FSID but curently device didn't - * observe it. Meaning our fsid will be different than theirs. + * observe it. Meaning our fsid will be different than theirs. We need + * to handle two subcases : + * 1 - The fs still continues to have different METADATA/FSID uuids. + * 2 - The fs is switched back to its original FSID (METADATA/FSID + * are equal). */ list_for_each_entry(fs_devices, &fs_uuids, fs_list) { + /* Changed UUIDs */ if (memcmp(fs_devices->metadata_uuid, fs_devices->fsid, BTRFS_FSID_SIZE) != 0 && memcmp(fs_devices->metadata_uuid, disk_super->metadata_uuid, BTRFS_FSID_SIZE) == 0 && memcmp(fs_devices->fsid, disk_super->fsid, - BTRFS_FSID_SIZE) != 0) { + BTRFS_FSID_SIZE) != 0) + return fs_devices; + + /* Unchanged UUIDs */ + if (memcmp(fs_devices->metadata_uuid, fs_devices->fsid, + BTRFS_FSID_SIZE) == 0 && + memcmp(fs_devices->fsid, disk_super->metadata_uuid, + BTRFS_FSID_SIZE) == 0) + return fs_devices; + } + + return NULL; +} + +static struct btrfs_fs_devices *find_fsid_reverted_metadata( + struct btrfs_super_block *disk_super) +{ + struct btrfs_fs_devices *fs_devices; + + /* + * Handle the case where the scanned device is part of an fs whose last + * metadata UUID change reverted it to the original FSID. At the same + * time * fs_devices was first created by another constitutent device + * which didn't fully observe the operation. This results in an + * btrfs_fs_devices created with metadata/fsid different AND + * btrfs_fs_devices::fsid_change set AND the metadata_uuid of the + * fs_devices equal to the FSID of the disk. + */ + list_for_each_entry(fs_devices, &fs_uuids, fs_list) { + if (memcmp(fs_devices->fsid, fs_devices->metadata_uuid, + BTRFS_FSID_SIZE) != 0 && + memcmp(fs_devices->metadata_uuid, disk_super->fsid, + BTRFS_FSID_SIZE) == 0 && + fs_devices->fsid_change) return fs_devices; - } } return NULL; @@ -943,7 +990,9 @@ static noinline struct btrfs_device *device_list_add(const char *path, fs_devices = find_fsid(disk_super->fsid, disk_super->metadata_uuid); } else { - fs_devices = find_fsid(disk_super->fsid, NULL); + fs_devices = find_fsid_reverted_metadata(disk_super); + if (!fs_devices) + fs_devices = find_fsid(disk_super->fsid, NULL); } @@ -973,12 +1022,18 @@ static noinline struct btrfs_device *device_list_add(const char *path, * a device which had the CHANGING_FSID_V2 flag then replace the * metadata_uuid/fsid values of the fs_devices. */ - if (has_metadata_uuid && fs_devices->fsid_change && + if (fs_devices->fsid_change && found_transid > fs_devices->latest_generation) { memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE); - memcpy(fs_devices->metadata_uuid, - disk_super->metadata_uuid, BTRFS_FSID_SIZE); + + if (has_metadata_uuid) + memcpy(fs_devices->metadata_uuid, + disk_super->metadata_uuid, + BTRFS_FSID_SIZE); + else + memcpy(fs_devices->metadata_uuid, + disk_super->fsid, BTRFS_FSID_SIZE); fs_devices->fsid_change = false; } @@ -1182,6 +1237,8 @@ again: &device->dev_state)) { if (!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state) && + !test_bit(BTRFS_DEV_STATE_MISSING, + &device->dev_state) && (!latest_dev || device->generation > latest_dev->generation)) { latest_dev = device; @@ -1375,8 +1432,14 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int ret; lockdep_assert_held(&uuid_mutex); + /* + * The device_list_mutex cannot be taken here in case opening the + * underlying device takes further locks like bd_mutex. + * + * We also don't need the lock here as this is called during mount and + * exclusion is provided by uuid_mutex + */ - mutex_lock(&fs_devices->device_list_mutex); if (fs_devices->opened) { fs_devices->opened++; ret = 0; @@ -1384,7 +1447,6 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, list_sort(NULL, &fs_devices->devices, devid_cmp); ret = open_fs_devices(fs_devices, flags, holder); } - mutex_unlock(&fs_devices->device_list_mutex); return ret; } @@ -4079,7 +4141,11 @@ int btrfs_balance(struct btrfs_fs_info *fs_info, } } - num_devices = btrfs_num_devices(fs_info); + /* + * rw_devices will not change at the moment, device add/delete/replace + * are excluded by EXCL_OP + */ + num_devices = fs_info->fs_devices->rw_devices; allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE | BTRFS_BLOCK_GROUP_DUP; if (num_devices > 1) @@ -6649,8 +6715,7 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info, else generate_random_uuid(dev->uuid); - btrfs_init_work(&dev->work, btrfs_submit_helper, - pending_bios_fn, NULL, NULL); + btrfs_init_work(&dev->work, pending_bios_fn, NULL, NULL); return dev; } @@ -7180,7 +7245,14 @@ int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info) * otherwise we don't need it. */ mutex_lock(&uuid_mutex); - mutex_lock(&fs_info->chunk_mutex); + + /* + * It is possible for mount and umount to race in such a way that + * we execute this code path, but open_fs_devices failed to clear + * total_rw_bytes. We certainly want it cleared before reading the + * device items, so clear it here. + */ + fs_info->fs_devices->total_rw_bytes = 0; /* * Read all device items, and then all the chunk items. All @@ -7217,7 +7289,9 @@ int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info) } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) { struct btrfs_chunk *chunk; chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk); + mutex_lock(&fs_info->chunk_mutex); ret = read_one_chunk(&found_key, leaf, chunk); + mutex_unlock(&fs_info->chunk_mutex); if (ret) goto error; } @@ -7247,7 +7321,6 @@ int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info) } ret = 0; error: - mutex_unlock(&fs_info->chunk_mutex); mutex_unlock(&uuid_mutex); btrfs_free_path(path); @@ -7509,6 +7582,8 @@ int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info, else btrfs_dev_stat_reset(dev, i); } + btrfs_info(fs_info, "device stats zeroed by %s (%d)", + current->comm, task_pid_nr(current)); } else { for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) if (stats->nr_items > i) |