@@ -116,6 +116,21 @@ Description:
device, and "0\n" if it is cleared. UBI devices mark themselves
as read-only when they detect an unrecoverable error.
+What: /sys/class/ubi/ubiX/fastmap
+Date: June 2019
+KernelVersion: 5.2
+Contact: linux-mtd@lists.infradead.org
+Description:
+ Contains ASCII "1\n" if there exists a fastmap on UBI device,
+ and "0\n" if there not exists a fastmap on UBI device. After
+ attaching the UBI device to a MTD device via fastmap, userspace
+ tool can sense that there is a fastmap on UBI device by
+ checking sysfs attribute 'fastmap', that is, the fastmap
+ generated before last detaching operation is valid. In addition,
+ userspace tool can also check whether the fastmap updating
+ triggered by volume operation is successful by reading this
+ sysfs attribute.
+
What: /sys/class/ubi/ubiX/total_eraseblocks
Date: July 2006
KernelVersion: 2.6.22
@@ -140,6 +140,8 @@ static struct device_attribute dev_mtd_num =
__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL); static struct device_attribute dev_ro_mode =
__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
+static struct device_attribute dev_fastmap =
+ __ATTR(fastmap, S_IRUGO, dev_attribute_show, NULL);
/**
* ubi_volume_notify - send a volume change notification.
@@ -378,7 +380,11 @@ static ssize_t dev_attribute_show(struct device *dev,
ping ~ -----邮件原件----- 发件人: chengzhihao 发送时间: 2019年6月28日 20:06 收件人: david.oberhollenzer@sigma-star.at; richard@nod.at; david@sigma-star.at; boris.brezillon@free-electrons.com; zhangyi (F) <yi.zhang@huawei.com> 抄送: linux-mtd@lists.infradead.org; linux-kernel@vger.kernel.org; chengzhihao <chengzhihao1@huawei.com> 主题: [PATCH RFC v2] mtd: ubi: Add fastmap sysfs attribute The UBI device can be attached to a MTD device via fastmap by setting CONFIG_MTD_UBI_FASTMAP to 'y' (If there already exists a fastmap on the UBI device). To support some debugging scenarios, attaching process by fastmap can be confirmed in dmesg. If the UBI device is attached by fastmap, logs like following will appear in dmesg: ubi0: attached by fastmap If multiple UBI devices are attached to multiple MTD devices at the same time, how to distinguish which UBI devices are successfully attached by fastmap? Extracting attaching information for each UBI device one by one from dmesg is a way. A better method is to record fastmap existence in sysfs, so it can be obtained by userspace tools. This patch exposes fastmap on sysfs. Suppose you attach an UBI device to a MTD device by fastmap: if fastmap equals to '1', that is, the fastmap generated before last detaching operation is confirmed valid. Else, there may be some problems with old fastmap. Besides, userspace tool can also check whether the fastmap updating triggered by other operations (such as resize volume) is successful by reading this sysfs attribute. Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> --- Documentation/ABI/stable/sysfs-class-ubi | 15 +++++++++++++++ drivers/mtd/ubi/build.c | 9 ++++++++- 2 files changed, 23 insertions(+), 1 deletion(-) ret = sprintf(buf, "%d\n", ubi->mtd->index); else if (attr == &dev_ro_mode) ret = sprintf(buf, "%d\n", ubi->ro_mode); - else + else if (attr == &dev_fastmap) { + down_write(&ubi->fm_protect); + ret = sprintf(buf, "%d\n", ubi->fm ? 1 : 0); + up_write(&ubi->fm_protect); + } else ret = -EINVAL; ubi_put_device(ubi); @@ -398,6 +404,7 @@ static struct attribute *ubi_dev_attrs[] = { &dev_bgt_enabled.attr, &dev_mtd_num.attr, &dev_ro_mode.attr, + &dev_fastmap.attr, NULL }; ATTRIBUTE_GROUPS(ubi_dev); -- 2.7.4