From: Anand Jain Date: Mon, 6 Jan 2020 11:38:31 +0000 (+0800) Subject: btrfs: sysfs, add devid/dev_state kobject and device attributes X-Git-Tag: v5.6-rc1~157^2~8 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=668e48af7a94985be7cf3b97a860d9819271d8bf;p=linux.git btrfs: sysfs, add devid/dev_state kobject and device attributes New sysfs attributes that track the filesystem status of devices, stored in the per-filesystem directory in /sys/fs/btrfs/FSID/devinfo . There's a directory for each device, with name corresponding to the numerical device id. in_fs_metadata - device is in the list of fs metadata missing - device is missing (no device node or block device) replace_target - device is target of replace writeable - writes from fs are allowed These attributes reflect the state of the device::dev_state and created at mount time. Sample output: $ pwd /sys/fs/btrfs/6e1961f1-5918-4ecc-a22f-948897b409f7/devinfo/1/ $ ls in_fs_metadata missing replace_target writeable $ cat missing 0 The output from these attributes are 0 or 1. 0 indicates unset and 1 indicates set. These attributes are readonly. It is observed that the device delete thread and sysfs read thread will not race because the delete thread calls sysfs kobject_put() which in turn waits for existing sysfs read to complete. Note for device replace devid swap: During the replace the target device temporarily assumes devid 0 before assigning the devid of the soruce device. In btrfs_dev_replace_finishing() we remove source sysfs devid using the function btrfs_sysfs_remove_devices_attr(), so after that call kobject_rename() to update the devid in the sysfs. This adds and calls btrfs_sysfs_update_devid() helper function to update the device id. Signed-off-by: Anand Jain Reviewed-by: David Sterba [ update changelog ] Signed-off-by: David Sterba --- diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index f639dde2a679..8600beb9c086 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -707,6 +707,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, /* replace the sysfs entry */ btrfs_sysfs_rm_device_link(fs_info->fs_devices, src_device); + btrfs_sysfs_update_devid(tgt_device); btrfs_rm_dev_replace_free_srcdev(src_device); /* write back the superblocks */ diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 55e4ed1af29c..7436422194da 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -1152,29 +1152,117 @@ int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices, if (!fs_devices->devices_kobj) return -EINVAL; - if (one_device && one_device->bdev) { - disk = one_device->bdev->bd_part; - disk_kobj = &part_to_dev(disk)->kobj; + if (one_device) { + if (one_device->bdev) { + disk = one_device->bdev->bd_part; + disk_kobj = &part_to_dev(disk)->kobj; + sysfs_remove_link(fs_devices->devices_kobj, + disk_kobj->name); + } - sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name); - } + kobject_del(&one_device->devid_kobj); + kobject_put(&one_device->devid_kobj); + + wait_for_completion(&one_device->kobj_unregister); - if (one_device) return 0; + } - list_for_each_entry(one_device, - &fs_devices->devices, dev_list) { - if (!one_device->bdev) - continue; - disk = one_device->bdev->bd_part; - disk_kobj = &part_to_dev(disk)->kobj; + list_for_each_entry(one_device, &fs_devices->devices, dev_list) { + + if (one_device->bdev) { + disk = one_device->bdev->bd_part; + disk_kobj = &part_to_dev(disk)->kobj; + sysfs_remove_link(fs_devices->devices_kobj, + disk_kobj->name); + } + kobject_del(&one_device->devid_kobj); + kobject_put(&one_device->devid_kobj); - sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name); + wait_for_completion(&one_device->kobj_unregister); } return 0; } +static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj, + struct kobj_attribute *a, + char *buf) +{ + int val; + struct btrfs_device *device = container_of(kobj, struct btrfs_device, + devid_kobj); + + val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state); + + return snprintf(buf, PAGE_SIZE, "%d\n", val); +} +BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show); + +static ssize_t btrfs_sysfs_missing_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + int val; + struct btrfs_device *device = container_of(kobj, struct btrfs_device, + devid_kobj); + + val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state); + + return snprintf(buf, PAGE_SIZE, "%d\n", val); +} +BTRFS_ATTR(devid, missing, btrfs_sysfs_missing_show); + +static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj, + struct kobj_attribute *a, + char *buf) +{ + int val; + struct btrfs_device *device = container_of(kobj, struct btrfs_device, + devid_kobj); + + val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state); + + return snprintf(buf, PAGE_SIZE, "%d\n", val); +} +BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show); + +static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + int val; + struct btrfs_device *device = container_of(kobj, struct btrfs_device, + devid_kobj); + + val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state); + + return snprintf(buf, PAGE_SIZE, "%d\n", val); +} +BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show); + +static struct attribute *devid_attrs[] = { + BTRFS_ATTR_PTR(devid, in_fs_metadata), + BTRFS_ATTR_PTR(devid, missing), + BTRFS_ATTR_PTR(devid, replace_target), + BTRFS_ATTR_PTR(devid, writeable), + NULL +}; +ATTRIBUTE_GROUPS(devid); + +static void btrfs_release_devid_kobj(struct kobject *kobj) +{ + struct btrfs_device *device = container_of(kobj, struct btrfs_device, + devid_kobj); + + memset(&device->devid_kobj, 0, sizeof(struct kobject)); + complete(&device->kobj_unregister); +} + +static struct kobj_type devid_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .default_groups = devid_groups, + .release = btrfs_release_devid_kobj, +}; + int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices, struct btrfs_device *one_device) { @@ -1182,22 +1270,31 @@ int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices, struct btrfs_device *dev; list_for_each_entry(dev, &fs_devices->devices, dev_list) { - struct hd_struct *disk; - struct kobject *disk_kobj; - - if (!dev->bdev) - continue; if (one_device && one_device != dev) continue; - disk = dev->bdev->bd_part; - disk_kobj = &part_to_dev(disk)->kobj; + if (dev->bdev) { + struct hd_struct *disk; + struct kobject *disk_kobj; + + disk = dev->bdev->bd_part; + disk_kobj = &part_to_dev(disk)->kobj; + + error = sysfs_create_link(fs_devices->devices_kobj, + disk_kobj, disk_kobj->name); + if (error) + break; + } - error = sysfs_create_link(fs_devices->devices_kobj, - disk_kobj, disk_kobj->name); - if (error) + init_completion(&dev->kobj_unregister); + error = kobject_init_and_add(&dev->devid_kobj, &devid_ktype, + fs_devices->devices_kobj, "%llu", + dev->devid); + if (error) { + kobject_put(&dev->devid_kobj); break; + } } return error; @@ -1229,6 +1326,18 @@ void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices, "sysfs: failed to create fsid for sprout"); } +void btrfs_sysfs_update_devid(struct btrfs_device *device) +{ + char tmp[24]; + + snprintf(tmp, sizeof(tmp), "%llu", device->devid); + + if (kobject_rename(&device->devid_kobj, tmp)) + btrfs_warn(device->fs_devices->fs_info, + "sysfs: failed to update devid for %llu", + device->devid); +} + /* /sys/fs/btrfs/ entry */ static struct kset *btrfs_kset; diff --git a/fs/btrfs/sysfs.h b/fs/btrfs/sysfs.h index 3d27b39eaf94..c68582add92e 100644 --- a/fs/btrfs/sysfs.h +++ b/fs/btrfs/sysfs.h @@ -34,5 +34,6 @@ void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache); int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info, struct btrfs_space_info *space_info); void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info); +void btrfs_sysfs_update_devid(struct btrfs_device *device); #endif diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 9c7d4fe5c39a..690d4f5a0653 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -136,6 +136,10 @@ struct btrfs_device { atomic_t dev_stat_values[BTRFS_DEV_STAT_VALUES_MAX]; struct extent_io_tree alloc_state; + + struct completion kobj_unregister; + /* For sysfs/FSID/devinfo/devid/ */ + struct kobject devid_kobj; }; /*