Follow-up:

- filecache code clean-ups
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Merge tag 'nfsd-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull more nfsd updates from Chuck Lever:

 - filecache code clean-ups

* tag 'nfsd-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  nfsd: rework hashtable handling in nfsd_do_file_acquire
  nfsd: fix nfsd_file_unhash_and_dispose
This commit is contained in:
Linus Torvalds 2022-10-10 19:58:04 -07:00
commit dc91485856

View File

@ -405,22 +405,15 @@ nfsd_file_unhash(struct nfsd_file *nf)
return false;
}
/*
* Return true if the file was unhashed.
*/
static bool
static void
nfsd_file_unhash_and_dispose(struct nfsd_file *nf, struct list_head *dispose)
{
trace_nfsd_file_unhash_and_dispose(nf);
if (!nfsd_file_unhash(nf))
return false;
/* keep final reference for nfsd_file_lru_dispose */
if (refcount_dec_not_one(&nf->nf_ref))
return true;
nfsd_file_lru_remove(nf);
list_add(&nf->nf_lru, dispose);
return true;
if (nfsd_file_unhash(nf)) {
/* caller must call nfsd_file_dispose_list() later */
nfsd_file_lru_remove(nf);
list_add(&nf->nf_lru, dispose);
}
}
static void
@ -562,8 +555,6 @@ nfsd_file_dispose_list_delayed(struct list_head *dispose)
* @lock: LRU list lock (unused)
* @arg: dispose list
*
* Note this can deadlock with nfsd_file_cache_purge.
*
* Return values:
* %LRU_REMOVED: @item was removed from the LRU
* %LRU_ROTATE: @item is to be moved to the LRU tail
@ -748,8 +739,6 @@ nfsd_file_close_inode(struct inode *inode)
*
* Walk the LRU list and close any entries that have not been used since
* the last scan.
*
* Note this can deadlock with nfsd_file_cache_purge.
*/
static void
nfsd_file_delayed_close(struct work_struct *work)
@ -891,16 +880,12 @@ out_err:
goto out;
}
/*
* Note this can deadlock with nfsd_file_lru_cb.
*/
static void
__nfsd_file_cache_purge(struct net *net)
{
struct rhashtable_iter iter;
struct nfsd_file *nf;
LIST_HEAD(dispose);
bool del;
rhashtable_walk_enter(&nfsd_file_rhash_tbl, &iter);
do {
@ -910,14 +895,7 @@ __nfsd_file_cache_purge(struct net *net)
while (!IS_ERR_OR_NULL(nf)) {
if (net && nf->nf_net != net)
continue;
del = nfsd_file_unhash_and_dispose(nf, &dispose);
/*
* Deadlock detected! Something marked this entry as
* unhased, but hasn't removed it from the hash list.
*/
WARN_ON_ONCE(!del);
nfsd_file_unhash_and_dispose(nf, &dispose);
nf = rhashtable_walk_next(&iter);
}
@ -1064,9 +1042,10 @@ 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);
@ -1076,35 +1055,33 @@ 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;
ret = rhashtable_lookup_insert_key(&nfsd_file_rhash_tbl,
&key, &nf->nf_rhash,
nfsd_file_rhash_params);
if (likely(ret == 0))
goto open_file;
}
if (IS_ERR(nf))
goto insert_err;
nf = nfsd_file_get(nf);
if (nf == NULL) {
nf = new;
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);
@ -1112,11 +1089,11 @@ wait_for_construction:
/* 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;
}
@ -1164,13 +1141,6 @@ open_file:
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;
}
/**