60 строки
1.6 KiB
C
60 строки
1.6 KiB
C
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/*
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* Common code for control of lockd and nfsv4 grace periods.
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*/
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#include <linux/module.h>
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#include <linux/lockd/bind.h>
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static LIST_HEAD(grace_list);
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static DEFINE_SPINLOCK(grace_lock);
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/**
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* locks_start_grace
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* @lm: who this grace period is for
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*
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* A grace period is a period during which locks should not be given
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* out. Currently grace periods are only enforced by the two lock
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* managers (lockd and nfsd), using the locks_in_grace() function to
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* check when they are in a grace period.
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*
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* This function is called to start a grace period.
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*/
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void locks_start_grace(struct lock_manager *lm)
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{
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spin_lock(&grace_lock);
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list_add(&lm->list, &grace_list);
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spin_unlock(&grace_lock);
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}
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EXPORT_SYMBOL_GPL(locks_start_grace);
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/**
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* locks_end_grace
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* @lm: who this grace period is for
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*
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* Call this function to state that the given lock manager is ready to
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* resume regular locking. The grace period will not end until all lock
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* managers that called locks_start_grace() also call locks_end_grace().
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* Note that callers count on it being safe to call this more than once,
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* and the second call should be a no-op.
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*/
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void locks_end_grace(struct lock_manager *lm)
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{
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spin_lock(&grace_lock);
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list_del_init(&lm->list);
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spin_unlock(&grace_lock);
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}
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EXPORT_SYMBOL_GPL(locks_end_grace);
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/**
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* locks_in_grace
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*
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* Lock managers call this function to determine when it is OK for them
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* to answer ordinary lock requests, and when they should accept only
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* lock reclaims.
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*/
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int locks_in_grace(void)
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{
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return !list_empty(&grace_list);
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}
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EXPORT_SYMBOL_GPL(locks_in_grace);
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