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authorLinus Torvalds <torvalds@linux-foundation.org>2016-08-12 16:28:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-08-12 16:28:41 -0700
commitb112324c2b11e74ea6ed856d7db5cba5125acce3 (patch)
tree700e34e0cc0d43e3c2e6788326d4ad6972fd9cb2 /fs
parent9710cb662477ff18579814f11b2f4a4bc9b7d847 (diff)
parentdd257933fa4b9fea66a1195f8a15111029810abc (diff)
downloadlinux-b112324c2b11e74ea6ed856d7db5cba5125acce3.tar.bz2
Merge tag 'nfsd-4.8-1' of git://linux-nfs.org/~bfields/linux
Pull nfsd fixes from Bruce Fields: "Fixes for the dentry refcounting leak I introduced in 4.8-rc1, and for races in the LOCK code which appear to go back to the big nfsd state lock removal from 3.17" * tag 'nfsd-4.8-1' of git://linux-nfs.org/~bfields/linux: nfsd: don't return an unhashed lock stateid after taking mutex nfsd: Fix race between FREE_STATEID and LOCK nfsd: fix dentry refcounting on create
Diffstat (limited to 'fs')
-rw-r--r--fs/nfsd/nfs4state.c65
-rw-r--r--fs/nfsd/vfs.c9
2 files changed, 54 insertions, 20 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 8410ca275db1..a204d7e109d4 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4903,6 +4903,32 @@ nfsd4_test_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
return nfs_ok;
}
+static __be32
+nfsd4_free_lock_stateid(stateid_t *stateid, struct nfs4_stid *s)
+{
+ struct nfs4_ol_stateid *stp = openlockstateid(s);
+ __be32 ret;
+
+ mutex_lock(&stp->st_mutex);
+
+ ret = check_stateid_generation(stateid, &s->sc_stateid, 1);
+ if (ret)
+ goto out;
+
+ ret = nfserr_locks_held;
+ if (check_for_locks(stp->st_stid.sc_file,
+ lockowner(stp->st_stateowner)))
+ goto out;
+
+ release_lock_stateid(stp);
+ ret = nfs_ok;
+
+out:
+ mutex_unlock(&stp->st_mutex);
+ nfs4_put_stid(s);
+ return ret;
+}
+
__be32
nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
struct nfsd4_free_stateid *free_stateid)
@@ -4910,7 +4936,6 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
stateid_t *stateid = &free_stateid->fr_stateid;
struct nfs4_stid *s;
struct nfs4_delegation *dp;
- struct nfs4_ol_stateid *stp;
struct nfs4_client *cl = cstate->session->se_client;
__be32 ret = nfserr_bad_stateid;
@@ -4929,18 +4954,9 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
ret = nfserr_locks_held;
break;
case NFS4_LOCK_STID:
- ret = check_stateid_generation(stateid, &s->sc_stateid, 1);
- if (ret)
- break;
- stp = openlockstateid(s);
- ret = nfserr_locks_held;
- if (check_for_locks(stp->st_stid.sc_file,
- lockowner(stp->st_stateowner)))
- break;
- WARN_ON(!unhash_lock_stateid(stp));
+ atomic_inc(&s->sc_count);
spin_unlock(&cl->cl_lock);
- nfs4_put_stid(s);
- ret = nfs_ok;
+ ret = nfsd4_free_lock_stateid(stateid, s);
goto out;
case NFS4_REVOKED_DELEG_STID:
dp = delegstateid(s);
@@ -5507,7 +5523,7 @@ static __be32
lookup_or_create_lock_state(struct nfsd4_compound_state *cstate,
struct nfs4_ol_stateid *ost,
struct nfsd4_lock *lock,
- struct nfs4_ol_stateid **lst, bool *new)
+ struct nfs4_ol_stateid **plst, bool *new)
{
__be32 status;
struct nfs4_file *fi = ost->st_stid.sc_file;
@@ -5515,7 +5531,9 @@ lookup_or_create_lock_state(struct nfsd4_compound_state *cstate,
struct nfs4_client *cl = oo->oo_owner.so_client;
struct inode *inode = d_inode(cstate->current_fh.fh_dentry);
struct nfs4_lockowner *lo;
+ struct nfs4_ol_stateid *lst;
unsigned int strhashval;
+ bool hashed;
lo = find_lockowner_str(cl, &lock->lk_new_owner);
if (!lo) {
@@ -5531,12 +5549,27 @@ lookup_or_create_lock_state(struct nfsd4_compound_state *cstate,
goto out;
}
- *lst = find_or_create_lock_stateid(lo, fi, inode, ost, new);
- if (*lst == NULL) {
+retry:
+ lst = find_or_create_lock_stateid(lo, fi, inode, ost, new);
+ if (lst == NULL) {
status = nfserr_jukebox;
goto out;
}
+
+ mutex_lock(&lst->st_mutex);
+
+ /* See if it's still hashed to avoid race with FREE_STATEID */
+ spin_lock(&cl->cl_lock);
+ hashed = !list_empty(&lst->st_perfile);
+ spin_unlock(&cl->cl_lock);
+
+ if (!hashed) {
+ mutex_unlock(&lst->st_mutex);
+ nfs4_put_stid(&lst->st_stid);
+ goto retry;
+ }
status = nfs_ok;
+ *plst = lst;
out:
nfs4_put_stateowner(&lo->lo_owner);
return status;
@@ -5603,8 +5636,6 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
goto out;
status = lookup_or_create_lock_state(cstate, open_stp, lock,
&lock_stp, &new);
- if (status == nfs_ok)
- mutex_lock(&lock_stp->st_mutex);
} else {
status = nfs4_preprocess_seqid_op(cstate,
lock->lk_old_lock_seqid,
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index ba944123167b..ff476e654b8f 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1252,10 +1252,13 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
if (IS_ERR(dchild))
return nfserrno(host_err);
err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
- if (err) {
- dput(dchild);
+ /*
+ * We unconditionally drop our ref to dchild as fh_compose will have
+ * already grabbed its own ref for it.
+ */
+ dput(dchild);
+ if (err)
return err;
- }
return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
rdev, resfhp);
}