nfsd: Always lock state exclusively.
It used to be the case that state had an rwlock that was locked for write
by downgrades, but for read for upgrades (opens). Well, the problem is
if there are two competing opens for the same state, they step on
each other toes potentially leading to leaking file descriptors
from the state structure, since access mode is a bitmap only set once.
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index f5f82e1..c927d36 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3502,7 +3502,7 @@
stp->st_access_bmap = 0;
stp->st_deny_bmap = 0;
stp->st_openstp = NULL;
- init_rwsem(&stp->st_rwsem);
+ mutex_init(&stp->st_mutex);
list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids);
list_add(&stp->st_perfile, &fp->fi_stateids);
@@ -4335,10 +4335,10 @@
*/
if (stp) {
/* Stateid was found, this is an OPEN upgrade */
- down_read(&stp->st_rwsem);
+ mutex_lock(&stp->st_mutex);
status = nfs4_upgrade_open(rqstp, fp, current_fh, stp, open);
if (status) {
- up_read(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
goto out;
}
} else {
@@ -4348,19 +4348,19 @@
if (swapstp) {
nfs4_put_stid(&stp->st_stid);
stp = swapstp;
- down_read(&stp->st_rwsem);
+ mutex_lock(&stp->st_mutex);
status = nfs4_upgrade_open(rqstp, fp, current_fh,
stp, open);
if (status) {
- up_read(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
goto out;
}
goto upgrade_out;
}
- down_read(&stp->st_rwsem);
+ mutex_lock(&stp->st_mutex);
status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open);
if (status) {
- up_read(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
release_open_stateid(stp);
goto out;
}
@@ -4372,7 +4372,7 @@
}
upgrade_out:
nfs4_inc_and_copy_stateid(&open->op_stateid, &stp->st_stid);
- up_read(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
if (nfsd4_has_session(&resp->cstate)) {
if (open->op_deleg_want & NFS4_SHARE_WANT_NO_DELEG) {
@@ -4977,12 +4977,12 @@
* revoked delegations are kept only for free_stateid.
*/
return nfserr_bad_stateid;
- down_write(&stp->st_rwsem);
+ mutex_lock(&stp->st_mutex);
status = check_stateid_generation(stateid, &stp->st_stid.sc_stateid, nfsd4_has_session(cstate));
if (status == nfs_ok)
status = nfs4_check_fh(current_fh, &stp->st_stid);
if (status != nfs_ok)
- up_write(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
return status;
}
@@ -5030,7 +5030,7 @@
return status;
oo = openowner(stp->st_stateowner);
if (!(oo->oo_flags & NFS4_OO_CONFIRMED)) {
- up_write(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
nfs4_put_stid(&stp->st_stid);
return nfserr_bad_stateid;
}
@@ -5062,12 +5062,12 @@
oo = openowner(stp->st_stateowner);
status = nfserr_bad_stateid;
if (oo->oo_flags & NFS4_OO_CONFIRMED) {
- up_write(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
goto put_stateid;
}
oo->oo_flags |= NFS4_OO_CONFIRMED;
nfs4_inc_and_copy_stateid(&oc->oc_resp_stateid, &stp->st_stid);
- up_write(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
dprintk("NFSD: %s: success, seqid=%d stateid=" STATEID_FMT "\n",
__func__, oc->oc_seqid, STATEID_VAL(&stp->st_stid.sc_stateid));
@@ -5143,7 +5143,7 @@
nfs4_inc_and_copy_stateid(&od->od_stateid, &stp->st_stid);
status = nfs_ok;
put_stateid:
- up_write(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
nfs4_put_stid(&stp->st_stid);
out:
nfsd4_bump_seqid(cstate, status);
@@ -5196,7 +5196,7 @@
if (status)
goto out;
nfs4_inc_and_copy_stateid(&close->cl_stateid, &stp->st_stid);
- up_write(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
nfsd4_close_open_stateid(stp);
@@ -5422,7 +5422,7 @@
stp->st_access_bmap = 0;
stp->st_deny_bmap = open_stp->st_deny_bmap;
stp->st_openstp = open_stp;
- init_rwsem(&stp->st_rwsem);
+ mutex_init(&stp->st_mutex);
list_add(&stp->st_locks, &open_stp->st_locks);
list_add(&stp->st_perstateowner, &lo->lo_owner.so_stateids);
spin_lock(&fp->fi_lock);
@@ -5591,7 +5591,7 @@
&open_stp, nn);
if (status)
goto out;
- up_write(&open_stp->st_rwsem);
+ mutex_unlock(&open_stp->st_mutex);
open_sop = openowner(open_stp->st_stateowner);
status = nfserr_bad_stateid;
if (!same_clid(&open_sop->oo_owner.so_client->cl_clientid,
@@ -5600,7 +5600,7 @@
status = lookup_or_create_lock_state(cstate, open_stp, lock,
&lock_stp, &new);
if (status == nfs_ok)
- down_write(&lock_stp->st_rwsem);
+ mutex_lock(&lock_stp->st_mutex);
} else {
status = nfs4_preprocess_seqid_op(cstate,
lock->lk_old_lock_seqid,
@@ -5704,7 +5704,7 @@
seqid_mutating_err(ntohl(status)))
lock_sop->lo_owner.so_seqid++;
- up_write(&lock_stp->st_rwsem);
+ mutex_unlock(&lock_stp->st_mutex);
/*
* If this is a new, never-before-used stateid, and we are
@@ -5874,7 +5874,7 @@
fput:
fput(filp);
put_stateid:
- up_write(&stp->st_rwsem);
+ mutex_unlock(&stp->st_mutex);
nfs4_put_stid(&stp->st_stid);
out:
nfsd4_bump_seqid(cstate, status);
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 986e51e..64053ea 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -535,7 +535,7 @@
unsigned char st_access_bmap;
unsigned char st_deny_bmap;
struct nfs4_ol_stateid *st_openstp;
- struct rw_semaphore st_rwsem;
+ struct mutex st_mutex;
};
static inline struct nfs4_ol_stateid *openlockstateid(struct nfs4_stid *s)