• S
    ocfs2/dlm: Fix race during lockres mastery · 7b791d68
    Sunil Mushran 提交于
    dlm_get_lock_resource() is supposed to return a lock resource with a proper
    master. If multiple concurrent threads attempt to lookup the lockres for the
    same lockid while the lock mastery in underway, one or more threads are likely
    to return a lockres without a proper master.
    
    This patch makes the threads wait in dlm_get_lock_resource() while the mastery
    is underway, ensuring all threads return the lockres with a proper master.
    
    This issue is known to be limited to users using the flock() syscall. For all
    other fs operations, the ocfs2 dlmglue layer serializes the dlm op for each
    lockid.
    
    Users encountering this bug will see flock() return EINVAL and dmesg have the
    following error:
    ERROR: Dlm error "DLM_BADARGS" while calling dlmlock on resource <LOCKID>: bad api args
    Reported-by: NColy Li <coyli@suse.de>
    Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
    Signed-off-by: NMark Fasheh <mfasheh@suse.com>
    7b791d68
dlmmaster.c 94.1 KB