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authorChuck Lever <chuck.lever@oracle.com>2022-10-28 10:46:51 -0400
committerChuck Lever <chuck.lever@oracle.com>2022-11-28 12:54:45 -0500
commit4d1ea8455716ca070e3cd85767e6f6a562a58b1b (patch)
treea5fa7ecea46ed6691f33a9b43342c075bedfeaa5 /fs/nfsd/filecache.c
parentdcf3f80965ca787c70def402cdf1553c93c75529 (diff)
NFSD: Add an NFSD_FILE_GC flag to enable nfsd_file garbage collection
NFSv4 operations manage the lifetime of nfsd_file items they use by means of NFSv4 OPEN and CLOSE. Hence there's no need for them to be garbage collected. Introduce a mechanism to enable garbage collection for nfsd_file items used only by NFSv2/3 callers. Note that the change in nfsd_file_put() ensures that both CLOSE and DELEGRETURN will actually close out and free an nfsd_file on last reference of a non-garbage-collected file. Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=394 Suggested-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: NeilBrown <neilb@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org>
Diffstat (limited to 'fs/nfsd/filecache.c')
-rw-r--r--fs/nfsd/filecache.c63
1 files changed, 55 insertions, 8 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index babea79d3f6f..cee44405cf7d 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -63,6 +63,7 @@ struct nfsd_file_lookup_key {
struct net *net;
const struct cred *cred;
unsigned char need;
+ bool gc;
enum nfsd_file_lookup_type type;
};
@@ -162,6 +163,8 @@ static int nfsd_file_obj_cmpfn(struct rhashtable_compare_arg *arg,
return 1;
if (!nfsd_match_cred(nf->nf_cred, key->cred))
return 1;
+ if (!!test_bit(NFSD_FILE_GC, &nf->nf_flags) != key->gc)
+ return 1;
if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0)
return 1;
break;
@@ -297,6 +300,8 @@ nfsd_file_alloc(struct nfsd_file_lookup_key *key, unsigned int may)
nf->nf_flags = 0;
__set_bit(NFSD_FILE_HASHED, &nf->nf_flags);
__set_bit(NFSD_FILE_PENDING, &nf->nf_flags);
+ if (key->gc)
+ __set_bit(NFSD_FILE_GC, &nf->nf_flags);
nf->nf_inode = key->inode;
/* nf_ref is pre-incremented for hash table */
refcount_set(&nf->nf_ref, 2);
@@ -428,16 +433,27 @@ nfsd_file_put_noref(struct nfsd_file *nf)
}
}
+static void
+nfsd_file_unhash_and_put(struct nfsd_file *nf)
+{
+ if (nfsd_file_unhash(nf))
+ nfsd_file_put_noref(nf);
+}
+
void
nfsd_file_put(struct nfsd_file *nf)
{
might_sleep();
- nfsd_file_lru_add(nf);
- if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0) {
+ if (test_bit(NFSD_FILE_GC, &nf->nf_flags))
+ nfsd_file_lru_add(nf);
+ else if (refcount_read(&nf->nf_ref) == 2)
+ nfsd_file_unhash_and_put(nf);
+
+ if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
nfsd_file_flush(nf);
nfsd_file_put_noref(nf);
- } else if (nf->nf_file) {
+ } else if (nf->nf_file && test_bit(NFSD_FILE_GC, &nf->nf_flags)) {
nfsd_file_put_noref(nf);
nfsd_file_schedule_laundrette();
} else
@@ -1016,12 +1032,14 @@ nfsd_file_is_cached(struct inode *inode)
static __be32
nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
- unsigned int may_flags, struct nfsd_file **pnf, bool open)
+ unsigned int may_flags, struct nfsd_file **pnf,
+ bool open, bool want_gc)
{
struct nfsd_file_lookup_key key = {
.type = NFSD_FILE_KEY_FULL,
.need = may_flags & NFSD_FILE_MAY_MASK,
.net = SVC_NET(rqstp),
+ .gc = want_gc,
};
bool open_retry = true;
struct nfsd_file *nf;
@@ -1117,8 +1135,7 @@ open_file:
* then unhash.
*/
if (status != nfs_ok || key.inode->i_nlink == 0)
- if (nfsd_file_unhash(nf))
- nfsd_file_put_noref(nf);
+ nfsd_file_unhash_and_put(nf);
clear_bit_unlock(NFSD_FILE_PENDING, &nf->nf_flags);
smp_mb__after_atomic();
wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING);
@@ -1126,12 +1143,38 @@ open_file:
}
/**
+ * nfsd_file_acquire_gc - Get a struct nfsd_file with an open file
+ * @rqstp: the RPC transaction being executed
+ * @fhp: the NFS filehandle of the file to be opened
+ * @may_flags: NFSD_MAY_ settings for the file
+ * @pnf: OUT: new or found "struct nfsd_file" object
+ *
+ * The nfsd_file object returned by this API is reference-counted
+ * and garbage-collected. The object is retained for a few
+ * seconds after the final nfsd_file_put() in case the caller
+ * wants to re-use it.
+ *
+ * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in
+ * network byte order is returned.
+ */
+__be32
+nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ unsigned int may_flags, struct nfsd_file **pnf)
+{
+ return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true, true);
+}
+
+/**
* nfsd_file_acquire - Get a struct nfsd_file with an open file
* @rqstp: the RPC transaction being executed
* @fhp: the NFS filehandle of the file to be opened
* @may_flags: NFSD_MAY_ settings for the file
* @pnf: OUT: new or found "struct nfsd_file" object
*
+ * The nfsd_file_object returned by this API is reference-counted
+ * but not garbage-collected. The object is unhashed after the
+ * final nfsd_file_put().
+ *
* Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in
* network byte order is returned.
*/
@@ -1139,7 +1182,7 @@ __be32
nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true);
+ return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true, false);
}
/**
@@ -1149,6 +1192,10 @@ nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
* @may_flags: NFSD_MAY_ settings for the file
* @pnf: OUT: new or found "struct nfsd_file" object
*
+ * The nfsd_file_object returned by this API is reference-counted
+ * but not garbage-collected. The object is released immediately
+ * one RCU grace period after the final nfsd_file_put().
+ *
* Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in
* network byte order is returned.
*/
@@ -1156,7 +1203,7 @@ __be32
nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, false);
+ return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, false, false);
}
/*