diff options
| -rw-r--r-- | fs/btrfs/disk-io.c | 6 | ||||
| -rw-r--r-- | fs/btrfs/volumes.c | 34 | ||||
| -rw-r--r-- | fs/btrfs/volumes.h | 7 |
3 files changed, 45 insertions, 2 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 6c54c21..b7ddc77 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2111,7 +2111,7 @@ static int write_dev_supers(struct btrfs_device *device, int write_all_supers(struct btrfs_root *root, int max_mirrors) { - struct list_head *head = &root->fs_info->fs_devices->devices; + struct list_head *head; struct btrfs_device *dev; struct btrfs_super_block *sb; struct btrfs_dev_item *dev_item; @@ -2126,6 +2126,9 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors) sb = &root->fs_info->super_for_commit; dev_item = &sb->dev_item; + + mutex_lock(&root->fs_info->fs_devices->device_list_mutex); + head = &root->fs_info->fs_devices->devices; list_for_each_entry(dev, head, dev_list) { if (!dev->bdev) { total_errors++; @@ -2169,6 +2172,7 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors) if (ret) total_errors++; } + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); if (total_errors > max_errors) { printk(KERN_ERR "btrfs: %d errors while writing supers\n", total_errors); diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 3f4a593..3ab80e9 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -377,6 +377,7 @@ static noinline int device_list_add(const char *path, memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE); fs_devices->latest_devid = devid; fs_devices->latest_trans = found_transid; + mutex_init(&fs_devices->device_list_mutex); device = NULL; } else { device = __find_device(&fs_devices->devices, devid, @@ -403,7 +404,11 @@ static noinline int device_list_add(const char *path, return -ENOMEM; } INIT_LIST_HEAD(&device->dev_alloc_list); + + mutex_lock(&fs_devices->device_list_mutex); list_add(&device->dev_list, &fs_devices->devices); + mutex_unlock(&fs_devices->device_list_mutex); + device->fs_devices = fs_devices; fs_devices->num_devices++; } @@ -429,10 +434,12 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig) INIT_LIST_HEAD(&fs_devices->devices); INIT_LIST_HEAD(&fs_devices->alloc_list); INIT_LIST_HEAD(&fs_devices->list); + mutex_init(&fs_devices->device_list_mutex); fs_devices->latest_devid = orig->latest_devid; fs_devices->latest_trans = orig->latest_trans; memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid)); + mutex_lock(&orig->device_list_mutex); list_for_each_entry(orig_dev, &orig->devices, dev_list) { device = kzalloc(sizeof(*device), GFP_NOFS); if (!device) @@ -454,8 +461,10 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig) device->fs_devices = fs_devices; fs_devices->num_devices++; } + mutex_unlock(&orig->device_list_mutex); return fs_devices; error: + mutex_unlock(&orig->device_list_mutex); free_fs_devices(fs_devices); return ERR_PTR(-ENOMEM); } @@ -466,6 +475,7 @@ int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices) mutex_lock(&uuid_mutex); again: + mutex_lock(&fs_devices->device_list_mutex); list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) { if (device->in_fs_metadata) continue; @@ -485,6 +495,7 @@ again: kfree(device->name); kfree(device); } + mutex_unlock(&fs_devices->device_list_mutex); if (fs_devices->seed) { fs_devices = fs_devices->seed; @@ -1135,12 +1146,14 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path) device = NULL; devices = &root->fs_info->fs_devices->devices; + mutex_lock(&root->fs_info->fs_devices->device_list_mutex); list_for_each_entry(tmp, devices, dev_list) { if (tmp->in_fs_metadata && !tmp->bdev) { device = tmp; break; } } + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); bdev = NULL; bh = NULL; disk_super = NULL; @@ -1195,7 +1208,16 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path) goto error_brelse; device->in_fs_metadata = 0; + + /* + * the device list mutex makes sure that we don't change + * the device list while someone else is writing out all + * the device supers. + */ + mutex_lock(&root->fs_info->fs_devices->device_list_mutex); list_del_init(&device->dev_list); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + device->fs_devices->num_devices--; next_device = list_entry(root->fs_info->fs_devices->devices.next, @@ -1289,6 +1311,7 @@ static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans, seed_devices->opened = 1; INIT_LIST_HEAD(&seed_devices->devices); INIT_LIST_HEAD(&seed_devices->alloc_list); + mutex_init(&seed_devices->device_list_mutex); list_splice_init(&fs_devices->devices, &seed_devices->devices); list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list); list_for_each_entry(device, &seed_devices->devices, dev_list) { @@ -1414,6 +1437,10 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path) mutex_lock(&root->fs_info->volume_mutex); devices = &root->fs_info->fs_devices->devices; + /* + * we have the volume lock, so we don't need the extra + * device list mutex while reading the list here. + */ list_for_each_entry(device, devices, dev_list) { if (device->bdev == bdev) { ret = -EEXIST; @@ -1468,6 +1495,12 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path) } device->fs_devices = root->fs_info->fs_devices; + + /* + * we don't want write_supers to jump in here with our device + * half setup + */ + mutex_lock(&root->fs_info->fs_devices->device_list_mutex); list_add(&device->dev_list, &root->fs_info->fs_devices->devices); list_add(&device->dev_alloc_list, &root->fs_info->fs_devices->alloc_list); @@ -1486,6 +1519,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path) total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy); btrfs_set_super_num_devices(&root->fs_info->super_copy, total_bytes + 1); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); if (seeding_dev) { ret = init_first_rw_device(trans, root, device); diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 3c1f731..5139a83 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -96,7 +96,12 @@ struct btrfs_fs_devices { u64 rw_devices; u64 total_rw_bytes; struct block_device *latest_bdev; - /* all of the devices in the FS */ + + /* all of the devices in the FS, protected by a mutex + * so we can safely walk it to write out the supers without + * worrying about add/remove by the multi-device code + */ + struct mutex device_list_mutex; struct list_head devices; /* devices not currently being allocated */ |
