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@xxxxxxxxxxxxxxx> Tested-by: Jeff Layton <jlayton@xxxxxxxxxx> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- fs/nfsd/filecache.c | 61 +++++++++++++++++++++++++++++++++++++++++++++------ fs/nfsd/filecache.h | 3 +++ fs/nfsd/nfs3proc.c | 4 ++- fs/nfsd/trace.h | 3 ++- fs/nfsd/vfs.c | 4 ++- 5 files changed, 63 insertions(+), 12 deletions(-) diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index b7aa523c2010..87fce5c95726 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; + unsigned char gc:1; 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_GC, &nf->nf_flags) == 1) + 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) == 0) { 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) == 1) { nfsd_file_put_noref(nf); nfsd_file_schedule_laundrette(); } else @@ -1017,12 +1033,14 @@ 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, int 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; @@ -1117,14 +1135,35 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, * 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); goto out; } +/** + * 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, 1); +} + /** * nfsd_file_acquire - Get a struct nfsd_file with an open file * @rqstp: the RPC transaction being executed @@ -1132,6 +1171,10 @@ nfsd_file_do_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 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, 0); } /** @@ -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, 0); } /* diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h index f81c198f4ed6..0f6546bcd3e0 100644 --- a/fs/nfsd/filecache.h +++ b/fs/nfsd/filecache.h @@ -38,6 +38,7 @@ struct nfsd_file { #define NFSD_FILE_HASHED (0) #define NFSD_FILE_PENDING (1) #define NFSD_FILE_REFERENCED (2) +#define NFSD_FILE_GC (3) unsigned long nf_flags; struct inode *nf_inode; /* don't deref */ refcount_t nf_ref; @@ -55,6 +56,8 @@ void nfsd_file_put(struct nfsd_file *nf); struct nfsd_file *nfsd_file_get(struct nfsd_file *nf); void nfsd_file_close_inode_sync(struct inode *inode); bool nfsd_file_is_cached(struct inode *inode); +__be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp, + unsigned int may_flags, struct nfsd_file **nfp); __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, unsigned int may_flags, struct nfsd_file **nfp); __be32 nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp, diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c index d12823371857..6a5ad6c91d8e 100644 --- a/fs/nfsd/nfs3proc.c +++ b/fs/nfsd/nfs3proc.c @@ -779,8 +779,8 @@ nfsd3_proc_commit(struct svc_rqst *rqstp) (unsigned long long) argp->offset); fh_copy(&resp->fh, &argp->fh); - resp->status = nfsd_file_acquire(rqstp, &resp->fh, NFSD_MAY_WRITE | - NFSD_MAY_NOT_BREAK_LEASE, &nf); + resp->status = nfsd_file_acquire_gc(rqstp, &resp->fh, NFSD_MAY_WRITE | + NFSD_MAY_NOT_BREAK_LEASE, &nf); if (resp->status) goto out; resp->status = nfsd_commit(rqstp, &resp->fh, nf, argp->offset, diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index 9ebd67d461f9..4921144880d3 100644 --- a/fs/nfsd/trace.h +++ b/fs/nfsd/trace.h @@ -742,7 +742,8 @@ DEFINE_CLID_EVENT(confirmed_r); __print_flags(val, "|", \ { 1 << NFSD_FILE_HASHED, "HASHED" }, \ { 1 << NFSD_FILE_PENDING, "PENDING" }, \ - { 1 << NFSD_FILE_REFERENCED, "REFERENCED"}) + { 1 << NFSD_FILE_REFERENCED, "REFERENCED"}, \ + { 1 << NFSD_FILE_GC, "GC"}) DECLARE_EVENT_CLASS(nfsd_file_class, TP_PROTO(struct nfsd_file *nf), diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 44f210ba17cc..89d682a56fc4 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1060,7 +1060,7 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, __be32 err; trace_nfsd_read_start(rqstp, fhp, offset, *count); - err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf); + err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_READ, &nf); if (err) return err; @@ -1092,7 +1092,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, trace_nfsd_write_start(rqstp, fhp, offset, *cnt); - err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf); + err = nfsd_file_acquire_gc(rqstp, fhp, NFSD_MAY_WRITE, &nf); if (err) goto out;
