Allow changing active array's set_name. This is the only way to
safely update superblock on an array which carries a mounted fs.
Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
---
drivers/md/md.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 79 insertions(+)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index caca5d689cdc..59aa10669bef 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5051,6 +5051,84 @@ static struct md_sysfs_entry md_consistency_policy =
__ATTR(consistency_policy, S_IRUGO | S_IWUSR, consistency_policy_show,
consistency_policy_store);
+static ssize_t
+set_name_show(struct mddev *mddev, char *page)
+{
+ struct mdp_superblock_1 *sb;
+ struct md_rdev *rdev;
+ int err;
+
+ err = mddev_lock(mddev);
+ if (err)
+ return err;
+
+ /* only version-1 superblocks carry a MD set's name */
+ err = -ENXIO;
+ if (mddev->major_version != 1)
+ goto out_unlock;
+
+ err = -EINVAL;
+ rdev_for_each(rdev, mddev) {
+ if (WARN_ON(!rdev->sb_loaded))
+ continue;
+
+ sb = page_address(rdev->sb_page);
+ err = sprintf(page, "%.32s\n", sb->set_name);
+ break;
+ }
+
+out_unlock:
+ mddev_unlock(mddev);
+ return err;
+}
+
+static ssize_t
+set_name_store(struct mddev *mddev, const char *buf, size_t buflen)
+{
+ struct mdp_superblock_1 *sb;
+ struct md_rdev *rdev;
+ size_t len = buflen;
+ int err;
+
+ if (len && buf[len - 1] == '\n')
+ --len;
+
+ if (len > sizeof(sb->set_name))
+ return -ENOSPC;
+
+ err = mddev_lock(mddev);
+ if (err)
+ return err;
+
+ /* only version-1 superblocks carry a MD set's name */
+ err = -ENXIO;
+ if (mddev->major_version != 1)
+ goto out_unlock;
+
+ err = -EROFS;
+ if (mddev->ro)
+ goto out_unlock;
+
+ rdev_for_each(rdev, mddev) {
+ if (WARN_ON(!rdev->sb_loaded))
+ continue;
+
+ sb = page_address(rdev->sb_page);
+ memcpy(sb->set_name, buf, len);
+ memset(&sb->set_name[len], 0, sizeof(sb->set_name) - len);
+ }
+
+ md_update_sb(mddev, 1);
+ err = buflen;
+
+out_unlock:
+ mddev_unlock(mddev);
+ return err;
+}
+
+static struct md_sysfs_entry md_set_name =
+__ATTR(set_name, S_IRUGO | S_IWUSR, set_name_show, set_name_store);
+
static struct attribute *md_default_attrs[] = {
&md_level.attr,
&md_layout.attr,
@@ -5067,6 +5145,7 @@ static struct attribute *md_default_attrs[] = {
&md_array_size.attr,
&max_corr_read_errors.attr,
&md_consistency_policy.attr,
+ &md_set_name.attr,
NULL,
};
--
2.11.0
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