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cache: elide vhold/vdrop around promoting negative entry

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This commit is contained in:
Mateusz Guzik 2020-10-16 00:55:57 +00:00
parent 640e6162ee
commit 571bc3d1af
1 changed files with 4 additions and 5 deletions
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9
sys/kern/vfs_cache.c
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@ -3394,9 +3394,6 @@ cache_fplookup_negative_promote(struct cache_fpl *fpl, struct namecache *oncp,
cnp = fpl->cnp;
dvp = fpl->dvp;
if (!vhold_smr(dvp))
return (cache_fpl_aborted(fpl));
nl = NCP2NEGLIST(oncp);
cache_fpl_smr_exit(fpl);
@ -3409,6 +3406,10 @@ cache_fplookup_negative_promote(struct cache_fpl *fpl, struct namecache *oncp,
/*
* Avoid all surprises by only succeeding if we got the same entry and
* bailing completely otherwise.
* XXX There are no provisions to keep the vnode around, meaning we may
* end up promoting a negative entry for a *new* vnode and returning
* ENOENT on its account. This is the error we want to return anyway
* and promotion is harmless.
*
* In particular at this point there can be a new ncp which matches the
* search but hashes to a different neglist.
@ -3451,12 +3452,10 @@ cache_fplookup_negative_promote(struct cache_fpl *fpl, struct namecache *oncp,
counter_u64_add(numneghits, 1);
cache_fpl_smr_exit(fpl);
mtx_unlock(&nl->nl_lock);
vdrop(dvp);
return (cache_fpl_handled(fpl, ENOENT));
out_abort:
cache_fpl_smr_exit(fpl);
mtx_unlock(&nl->nl_lock);
vdrop(dvp);
return (cache_fpl_aborted(fpl));
}