[LU-18688] remove ojbects from restriper->mdr_migrating list under restriper's lock

• Type: Bug
• Resolution: Unresolved
• Priority: Minor
• Affects Version/s: Lustre 2.14.0, Lustre 2.16.1
• Severity: 3
• Assignee: Vladimir Saveliev
• Reporter: Vladimir Saveliev

Description

mdt_restripe_migrate_add() adds a stripe to migrating list of a restriper under restriper->mdr_lock:

void mdt_restripe_migrate_add(struct mdt_thread_info *info,
..
        spin_lock(&restriper->mdr_lock);
..
                list_add_tail(&o->mot_restripe_linkage,
                              &restriper->mdr_migrating);
..
        spin_unlock(&restriper->mdr_lock);

removal of a stripe from the migrating list is executed under mdt->mdt_lock (in mdt_restripe_migrate() and in mdt_restripe_migrate_finish()):

static int mdt_restripe_migrate(struct mdt_thread_info *info)
..
                spin_lock(&mdt->mdt_lock);
	        stripe->mot_restriping = 0;
	        list_del_init(&stripe->mot_restripe_linkage);
                spin_unlock(&mdt->mdt_lock);
..

That may cause list corruption.