nfsd: Add locking to the nfs4_file->fi_fds[] array
Preparation for removal of the client_mutex, which currently protects
this array. While we don't actually need the find_*_file_locked variants
just yet, a later patch will. So go ahead and add them now to reduce
future churn in this code.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index cfb10d0..314dc80 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -268,6 +268,79 @@
atomic_inc(&fi->fi_ref);
}
+static struct file *
+__nfs4_get_fd(struct nfs4_file *f, int oflag)
+{
+ if (f->fi_fds[oflag])
+ return get_file(f->fi_fds[oflag]);
+ return NULL;
+}
+
+static struct file *
+find_writeable_file_locked(struct nfs4_file *f)
+{
+ struct file *ret;
+
+ lockdep_assert_held(&f->fi_lock);
+
+ ret = __nfs4_get_fd(f, O_WRONLY);
+ if (!ret)
+ ret = __nfs4_get_fd(f, O_RDWR);
+ return ret;
+}
+
+static struct file *
+find_writeable_file(struct nfs4_file *f)
+{
+ struct file *ret;
+
+ spin_lock(&f->fi_lock);
+ ret = find_writeable_file_locked(f);
+ spin_unlock(&f->fi_lock);
+
+ return ret;
+}
+
+static struct file *find_readable_file_locked(struct nfs4_file *f)
+{
+ struct file *ret;
+
+ lockdep_assert_held(&f->fi_lock);
+
+ ret = __nfs4_get_fd(f, O_RDONLY);
+ if (!ret)
+ ret = __nfs4_get_fd(f, O_RDWR);
+ return ret;
+}
+
+static struct file *
+find_readable_file(struct nfs4_file *f)
+{
+ struct file *ret;
+
+ spin_lock(&f->fi_lock);
+ ret = find_readable_file_locked(f);
+ spin_unlock(&f->fi_lock);
+
+ return ret;
+}
+
+static struct file *
+find_any_file(struct nfs4_file *f)
+{
+ struct file *ret;
+
+ spin_lock(&f->fi_lock);
+ ret = __nfs4_get_fd(f, O_RDWR);
+ if (!ret) {
+ ret = __nfs4_get_fd(f, O_WRONLY);
+ if (!ret)
+ ret = __nfs4_get_fd(f, O_RDONLY);
+ }
+ spin_unlock(&f->fi_lock);
+ return ret;
+}
+
static int num_delegations;
unsigned long max_delegations;
@@ -316,20 +389,31 @@
__nfs4_file_get_access(fp, oflag);
}
-static void nfs4_file_put_fd(struct nfs4_file *fp, int oflag)
+static struct file *nfs4_file_put_fd(struct nfs4_file *fp, int oflag)
{
- if (fp->fi_fds[oflag]) {
- fput(fp->fi_fds[oflag]);
- fp->fi_fds[oflag] = NULL;
- }
+ struct file *filp;
+
+ filp = fp->fi_fds[oflag];
+ fp->fi_fds[oflag] = NULL;
+ return filp;
}
static void __nfs4_file_put_access(struct nfs4_file *fp, int oflag)
{
- if (atomic_dec_and_test(&fp->fi_access[oflag])) {
- nfs4_file_put_fd(fp, oflag);
+ might_lock(&fp->fi_lock);
+
+ if (atomic_dec_and_lock(&fp->fi_access[oflag], &fp->fi_lock)) {
+ struct file *f1 = NULL;
+ struct file *f2 = NULL;
+
+ f1 = nfs4_file_put_fd(fp, oflag);
if (atomic_read(&fp->fi_access[1 - oflag]) == 0)
- nfs4_file_put_fd(fp, O_RDWR);
+ f2 = nfs4_file_put_fd(fp, O_RDWR);
+ spin_unlock(&fp->fi_lock);
+ if (f1)
+ fput(f1);
+ if (f2)
+ fput(f2);
}
}
@@ -737,8 +821,10 @@
unhash_generic_stateid(stp);
unhash_stid(&stp->st_stid);
file = find_any_file(stp->st_file);
- if (file)
+ if (file) {
locks_remove_posix(file, (fl_owner_t)lockowner(stp->st_stateowner));
+ fput(file);
+ }
close_generic_stateid(stp);
free_generic_stateid(stp);
}
@@ -3206,17 +3292,27 @@
static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
struct svc_fh *cur_fh, struct nfsd4_open *open)
{
+ struct file *filp = NULL;
__be32 status;
int oflag = nfs4_access_to_omode(open->op_share_access);
int access = nfs4_access_to_access(open->op_share_access);
+ spin_lock(&fp->fi_lock);
if (!fp->fi_fds[oflag]) {
- status = nfsd_open(rqstp, cur_fh, S_IFREG, access,
- &fp->fi_fds[oflag]);
+ spin_unlock(&fp->fi_lock);
+ status = nfsd_open(rqstp, cur_fh, S_IFREG, access, &filp);
if (status)
goto out;
+ spin_lock(&fp->fi_lock);
+ if (!fp->fi_fds[oflag]) {
+ fp->fi_fds[oflag] = filp;
+ filp = NULL;
+ }
}
nfs4_file_get_access(fp, oflag);
+ spin_unlock(&fp->fi_lock);
+ if (filp)
+ fput(filp);
status = nfsd4_truncate(rqstp, cur_fh, open);
if (status)
@@ -3301,13 +3397,15 @@
if (status)
goto out_free;
fp->fi_lease = fl;
- fp->fi_deleg_file = get_file(fl->fl_file);
+ fp->fi_deleg_file = fl->fl_file;
atomic_set(&fp->fi_delegees, 1);
spin_lock(&state_lock);
hash_delegation_locked(dp, fp);
spin_unlock(&state_lock);
return 0;
out_free:
+ if (fl->fl_file)
+ fput(fl->fl_file);
locks_free_lock(fl);
return status;
}
@@ -3905,6 +4003,7 @@
status = nfserr_serverfault;
goto out;
}
+ get_file(file);
}
break;
case NFS4_OPEN_STID:
@@ -3932,7 +4031,7 @@
}
status = nfs_ok;
if (file)
- *filpp = get_file(file);
+ *filpp = file;
out:
nfs4_unlock_state();
return status;
@@ -4653,6 +4752,8 @@
break;
}
out:
+ if (filp)
+ fput(filp);
if (status && new_state)
release_lock_stateid(lock_stp);
nfsd4_bump_seqid(cstate, status);
@@ -4793,7 +4894,7 @@
if (!file_lock) {
dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
status = nfserr_jukebox;
- goto out;
+ goto fput;
}
locks_init_lock(file_lock);
file_lock->fl_type = F_UNLCK;
@@ -4815,7 +4916,8 @@
}
update_stateid(&stp->st_stid.sc_stateid);
memcpy(&locku->lu_stateid, &stp->st_stid.sc_stateid, sizeof(stateid_t));
-
+fput:
+ fput(filp);
out:
nfsd4_bump_seqid(cstate, status);
if (!cstate->replay_owner)
@@ -4826,7 +4928,7 @@
out_nfserr:
status = nfserrno(err);
- goto out;
+ goto fput;
}
/*