Unverified Commit 86fa3a75 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!4277 fs:/dcache.c: fix negative dentry limit not complete problem 

Merge Pull Request from: @ci-robot 
 
PR sync from: Long Li <leo.lilong@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/P6YF2R3PHVW3G7FTRR75BXQ6VA77KBOY/ 
 
https://gitee.com/openeuler/kernel/issues/I8WPQW 
 
Link:https://gitee.com/openeuler/kernel/pulls/4277

 

Reviewed-by: default avatarzhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: default avatarLiu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: default avatarZhang Changzhong <zhangchangzhong@huawei.com>
parents 81dcc378 0f4e7166

fs/dcache.c

+48 −22
Original line number Diff line number Diff line
@@ -636,10 +636,36 @@ static inline struct dentry *lock_parent(struct dentry *dentry) 
	return __lock_parent(dentry);

}



static inline bool retain_dentry(struct dentry *dentry)

/*

 * Return true if dentry is negative and exceed negative dentry limit.

 */

static inline bool limit_negative_dentry(struct dentry *dentry)

{

	struct dentry *parent;



	parent = dentry->d_parent;

	if (unlikely(!parent))

		return false;



	WARN_ON((atomic_read(&parent->d_neg_dnum) < 0));

	if (!dentry->d_inode) {

		if (!(dentry->d_flags & DCACHE_NEGATIVE_ACCOUNT)) {

			unsigned int flags = READ_ONCE(dentry->d_flags);



			flags |= DCACHE_NEGATIVE_ACCOUNT;

			WRITE_ONCE(dentry->d_flags, flags);

			atomic_inc(&parent->d_neg_dnum);

		}



		if (atomic_read(&parent->d_neg_dnum) >= NEG_DENTRY_LIMIT)

			return true;

	}



	return false;

}



static inline bool retain_dentry(struct dentry *dentry)

{

	WARN_ON(d_in_lookup(dentry));



	/* Unreachable? Get rid of it */
@@ -654,27 +680,9 @@ static inline bool retain_dentry(struct dentry *dentry) 
			return false;

	}



	if (unlikely(!dentry->d_parent))

		goto noparent;



	parent = dentry->d_parent;

	/* Return false if it's negative */

	WARN_ON((atomic_read(&parent->d_neg_dnum) < 0));

	if (!dentry->d_inode) {

		if (!(dentry->d_flags & DCACHE_NEGATIVE_ACCOUNT)) {

			unsigned flags = READ_ONCE(dentry->d_flags);



			flags |= DCACHE_NEGATIVE_ACCOUNT;

			WRITE_ONCE(dentry->d_flags, flags);

			atomic_inc(&parent->d_neg_dnum);

		}

	}



	if (!dentry->d_inode &&

	    atomic_read(&parent->d_neg_dnum) >= NEG_DENTRY_LIMIT)

	if (unlikely(limit_negative_dentry(dentry)))

		return false;



noparent:

	/* retain; LRU fodder */

	dentry->d_lockref.count--;

	if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST)))
@@ -808,8 +816,25 @@ static inline bool fast_dput(struct dentry *dentry) 
	d_flags &= DCACHE_REFERENCED | DCACHE_LRU_LIST | DCACHE_DISCONNECTED;



	/* Nothing to do? Dropping the reference was all we needed? */

	if (d_flags == (DCACHE_REFERENCED | DCACHE_LRU_LIST) && !d_unhashed(dentry))

	if (d_flags == (DCACHE_REFERENCED | DCACHE_LRU_LIST) && !d_unhashed(dentry)) {

		/*

		 * If the dentry is not negative dentry, return true directly,

		 * avoid holding dentry lock in the fast put path.

		 */

		if (dentry->d_inode)

			return true;

		/*

		 * If dentry is negative and need to be limitted, it maybe need

		 * to be killed, so shouldn't fast put and retain in memory.

		 */

		spin_lock(&dentry->d_lock);

		if (likely(!limit_negative_dentry(dentry))) {

			spin_unlock(&dentry->d_lock);

			return true;

		}



		goto dentry_locked;

	}



	/*

	 * Not the fast normal case? Get the lock. We've already decremented
@@ -818,6 +843,7 @@ static inline bool fast_dput(struct dentry *dentry) 
	 */

	spin_lock(&dentry->d_lock);



dentry_locked:

	/*

	 * Did somebody else grab a reference to it in the meantime, and

	 * we're no longer the last user after all? Alternatively, somebody