Fix for a bug caused by a race when 2 threads lookup the same
file. Leave the loser's lock(s) initialized, so the reclaim logic can unconditionally destroy them when that race occurs (or if the vfs hash insert happened to fail for some other reason). Thanks to ups@ for a careful review of the code. Reported by : Kris Kennaway
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parent
10d8cebc7a
commit
88d5725c38
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=164684
@ -148,6 +148,13 @@ nfs_nget(struct mount *mntp, nfsfh_t *fhp, int fhsize, struct nfsnode **npp, int
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vp->v_bufobj.bo_ops = &buf_ops_nfs;
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vp->v_data = np;
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np->n_vnode = vp;
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/*
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* Initialize the mutex even if the vnode is going to be a loser.
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* This simplifies the logic in reclaim, which can then unconditionally
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* destroy the mutex (in the case of the loser, or if hash_insert happened
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* to return an error no special casing is needed).
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*/
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mtx_init(&np->n_mtx, "NFSnode lock", NULL, MTX_DEF);
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/*
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* NFS supports recursive and shared locking.
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*/
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@ -168,7 +175,6 @@ nfs_nget(struct mount *mntp, nfsfh_t *fhp, int fhsize, struct nfsnode **npp, int
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np->n_fhp = &np->n_fh;
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bcopy((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize);
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np->n_fhsize = fhsize;
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mtx_init(&np->n_mtx, "NFSnode lock", NULL, MTX_DEF);
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*npp = np;
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return (0);
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