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NFSD: Add an NFSD_FILE_GC flag to enable nfsd_file garbage collection

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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>
This commit is contained in:
Chuck Lever 2022-10-28 10:46:51 -04:00
parent dcf3f80965
commit 4d1ea84557
5 changed files with 64 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

63
fs/nfsd/filecache.c
View File

@ -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;
@ -1117,14 +1135,35 @@ 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);
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, true);
}
/**
* nfsd_file_acquire - Get a struct nfsd_file with an open file
* @rqstp: the RPC transaction being executed
@ -1132,6 +1171,10 @@ open_file:
* @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);
}
/*

3
fs/nfsd/filecache.h
View File

@ -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,

4
fs/nfsd/nfs3proc.c
View File

@ -772,8 +772,8 @@ 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,

3
fs/nfsd/trace.h
View File

@ -817,7 +817,8 @@ 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),

4
fs/nfsd/vfs.c
View File

@ -1148,7 +1148,7 @@ __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;
@ -1180,7 +1180,7 @@ 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;