nfsd4: fix struct file leak

Make sure we properly reference count the struct files that a lock
depends on, and release them when the lock stateid is released.

This fixes a major leak of struct files when using locking over nfsv4.

Cc: stable@kernel.org
Reported-by: Rick Koshi <nfs-bug-report@more-right-rudder.com>
Tested-by: Ivo Přikryl <prikryl@eurosat.cz>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 21 insertions, 11 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 84d2dd327b2d..c26dc31fb943 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -397,6 +397,9 @@ static void unhash_generic_stateid(struct nfs4_stateid *stp)
 
 static void free_generic_stateid(struct nfs4_stateid *stp)
 {
+        int oflag = nfs4_access_bmap_to_omode(stp);
+
+        nfs4_file_put_access(stp->st_file, oflag);
         put_nfs4_file(stp->st_file);
         kmem_cache_free(stateid_slab, stp);
 }
@@ -448,11 +451,8 @@ release_stateid_lockowners(struct nfs4_stateid *open_stp)
 
 static void release_open_stateid(struct nfs4_stateid *stp)
 {
-        int oflag = nfs4_access_bmap_to_omode(stp);
-
         unhash_generic_stateid(stp);
         release_stateid_lockowners(stp);
-        nfs4_file_put_access(stp->st_file, oflag);
         free_generic_stateid(stp);
 }
 
@@ -3734,6 +3734,7 @@ alloc_init_lock_stateid(struct nfs4_stateowner *sop, struct nfs4_file *fp, struc
         stp->st_stateid.si_stateownerid = sop->so_id;
         stp->st_stateid.si_fileid = fp->fi_id;
         stp->st_stateid.si_generation = 0;
+        stp->st_access_bmap = 0;
         stp->st_deny_bmap = open_stp->st_deny_bmap;
         stp->st_openstp = open_stp;
 
@@ -3748,6 +3749,17 @@ check_lock_length(u64 offset, u64 length)
              LOFF_OVERFLOW(offset, length)));
 }
 
+static void get_lock_access(struct nfs4_stateid *lock_stp, u32 access)
+{
+        struct nfs4_file *fp = lock_stp->st_file;
+        int oflag = nfs4_access_to_omode(access);
+
+        if (test_bit(access, &lock_stp->st_access_bmap))
+                return;
+        nfs4_file_get_access(fp, oflag);
+        __set_bit(access, &lock_stp->st_access_bmap);
+}
+
 /*
  *  LOCK operation 
  */
@@ -3845,18 +3857,16 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         switch (lock->lk_type) {
                 case NFS4_READ_LT:
                 case NFS4_READW_LT:
-                        if (find_readable_file(lock_stp->st_file)) {
-                                nfs4_get_vfs_file(rqstp, fp, &cstate->current_fh, NFS4_SHARE_ACCESS_READ);
-                                filp = find_readable_file(lock_stp->st_file);
-                        }
+                        filp = find_readable_file(lock_stp->st_file);
+                        if (filp)
+                                get_lock_access(lock_stp, NFS4_SHARE_ACCESS_READ);
                         file_lock.fl_type = F_RDLCK;
                         break;
                 case NFS4_WRITE_LT:
                 case NFS4_WRITEW_LT:
-                        if (find_writeable_file(lock_stp->st_file)) {
-                                nfs4_get_vfs_file(rqstp, fp, &cstate->current_fh, NFS4_SHARE_ACCESS_WRITE);
-                                filp = find_writeable_file(lock_stp->st_file);
-                        }
+                        filp = find_writeable_file(lock_stp->st_file);
+                        if (filp)
+                                get_lock_access(lock_stp, NFS4_SHARE_ACCESS_WRITE);
                         file_lock.fl_type = F_WRLCK;
                         break;
                 default: