5.10-stable review patch. If anyone has any objections, please let me know.
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From: Jeff Layton jlayton@kernel.org
[ Upstream commit 243a5263014a30436c93ed3f1f864c1da845455e ]
nfsd_file is RCU-freed, so we need to hold the rcu_read_lock long enough to get a reference after finding it in the hash. Take the rcu_read_lock() and call rhashtable_lookup directly.
Switch to using rhashtable_lookup_insert_key as well, and use the usual retry mechanism if we hit an -EEXIST. Rename the "retry" bool to open_retry, and eliminiate the insert_err goto target.
Signed-off-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/filecache.c | 52 +++++++++++++++++++-------------------------- 1 file changed, 22 insertions(+), 30 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index a0d93e797cdce..0b19eb015c6c8 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -1041,9 +1041,10 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, .need = may_flags & NFSD_FILE_MAY_MASK, .net = SVC_NET(rqstp), }; - struct nfsd_file *nf, *new; - bool retry = true; + bool open_retry = true; + struct nfsd_file *nf; __be32 status; + int ret;
status = fh_verify(rqstp, fhp, S_IFREG, may_flags|NFSD_MAY_OWNER_OVERRIDE); @@ -1053,35 +1054,33 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, key.cred = get_current_cred();
retry: - /* Avoid allocation if the item is already in cache */ - nf = rhashtable_lookup_fast(&nfsd_file_rhash_tbl, &key, - nfsd_file_rhash_params); + rcu_read_lock(); + nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key, + nfsd_file_rhash_params); if (nf) nf = nfsd_file_get(nf); + rcu_read_unlock(); if (nf) goto wait_for_construction;
- new = nfsd_file_alloc(&key, may_flags); - if (!new) { + nf = nfsd_file_alloc(&key, may_flags); + if (!nf) { status = nfserr_jukebox; goto out_status; }
- nf = rhashtable_lookup_get_insert_key(&nfsd_file_rhash_tbl, - &key, &new->nf_rhash, - nfsd_file_rhash_params); - if (!nf) { - nf = new; - goto open_file; - } - if (IS_ERR(nf)) - goto insert_err; - nf = nfsd_file_get(nf); - if (nf == NULL) { - nf = new; + ret = rhashtable_lookup_insert_key(&nfsd_file_rhash_tbl, + &key, &nf->nf_rhash, + nfsd_file_rhash_params); + if (likely(ret == 0)) goto open_file; - } - nfsd_file_slab_free(&new->nf_rcu); + + nfsd_file_slab_free(&nf->nf_rcu); + if (ret == -EEXIST) + goto retry; + trace_nfsd_file_insert_err(rqstp, key.inode, may_flags, ret); + status = nfserr_jukebox; + goto out_status;
wait_for_construction: wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE); @@ -1089,11 +1088,11 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, /* Did construction of this file fail? */ if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { trace_nfsd_file_cons_err(rqstp, key.inode, may_flags, nf); - if (!retry) { + if (!open_retry) { status = nfserr_jukebox; goto out; } - retry = false; + open_retry = false; nfsd_file_put_noref(nf); goto retry; } @@ -1141,13 +1140,6 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, smp_mb__after_atomic(); wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING); goto out; - -insert_err: - nfsd_file_slab_free(&new->nf_rcu); - trace_nfsd_file_insert_err(rqstp, key.inode, may_flags, PTR_ERR(nf)); - nf = NULL; - status = nfserr_jukebox; - goto out_status; }
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