nfsd: Add fine grained protection for the nfs4_file->fi_stateids list

Access to this list is currently serialized by the client_mutex. Add
finer grained locking around this list in preparation for its removal.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

2 files changed, 19 insertions, 3 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3704789ca4b7..cfb10d060c83 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -708,7 +708,11 @@ release_all_access(struct nfs4_ol_stateid *stp)
 
 static void unhash_generic_stateid(struct nfs4_ol_stateid *stp)
 {
+        struct nfs4_file *fp = stp->st_file;
+
+        spin_lock(&fp->fi_lock);
         list_del(&stp->st_perfile);
+        spin_unlock(&fp->fi_lock);
         list_del(&stp->st_perstateowner);
 }
 
@@ -2676,6 +2680,7 @@ static void nfsd4_init_file(struct nfs4_file *fp, struct inode *ino)
         lockdep_assert_held(&state_lock);
 
         atomic_set(&fp->fi_ref, 1);
+        spin_lock_init(&fp->fi_lock);
         INIT_LIST_HEAD(&fp->fi_stateids);
         INIT_LIST_HEAD(&fp->fi_delegations);
         ihold(ino);
@@ -2799,7 +2804,6 @@ static void init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp,
         stp->st_stid.sc_type = NFS4_OPEN_STID;
         INIT_LIST_HEAD(&stp->st_locks);
         list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids);
-        list_add(&stp->st_perfile, &fp->fi_stateids);
         stp->st_stateowner = &oo->oo_owner;
         get_nfs4_file(fp);
         stp->st_file = fp;
@@ -2808,6 +2812,9 @@ static void init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp,
         set_access(open->op_share_access, stp);
         set_deny(open->op_share_deny, stp);
         stp->st_openstp = NULL;
+        spin_lock(&fp->fi_lock);
+        list_add(&stp->st_perfile, &fp->fi_stateids);
+        spin_unlock(&fp->fi_lock);
 }
 
 static void
@@ -2915,6 +2922,7 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
                 return nfs_ok;
         ret = nfserr_locked;
         /* Search for conflicting share reservations */
+        spin_lock(&fp->fi_lock);
         list_for_each_entry(stp, &fp->fi_stateids, st_perfile) {
                 if (test_deny(deny_type, stp) ||
                     test_deny(NFS4_SHARE_DENY_BOTH, stp))
@@ -2922,6 +2930,7 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
         }
         ret = nfs_ok;
 out:
+        spin_unlock(&fp->fi_lock);
         put_nfs4_file(fp);
         return ret;
 }
@@ -3150,6 +3159,7 @@ nfs4_check_open(struct nfs4_file *fp, struct nfsd4_open *open, struct nfs4_ol_st
         struct nfs4_ol_stateid *local;
         struct nfs4_openowner *oo = open->op_openowner;
 
+        spin_lock(&fp->fi_lock);
         list_for_each_entry(local, &fp->fi_stateids, st_perfile) {
                 /* ignore lock owners */
                 if (local->st_stateowner->so_is_open_owner == 0)
@@ -3158,9 +3168,12 @@ nfs4_check_open(struct nfs4_file *fp, struct nfsd4_open *open, struct nfs4_ol_st
                 if (local->st_stateowner == &oo->oo_owner)
                         *stpp = local;
                 /* check for conflicting share reservations */
-                if (!test_share(local, open))
+                if (!test_share(local, open)) {
+                        spin_unlock(&fp->fi_lock);
                         return nfserr_share_denied;
+                }
         }
+        spin_unlock(&fp->fi_lock);
         return nfs_ok;
 }
 
@@ -4408,7 +4421,6 @@ alloc_init_lock_stateid(struct nfs4_lockowner *lo, struct nfs4_file *fp, struct
         if (stp == NULL)
                 return NULL;
         stp->st_stid.sc_type = NFS4_LOCK_STID;
-        list_add(&stp->st_perfile, &fp->fi_stateids);
         list_add(&stp->st_perstateowner, &lo->lo_owner.so_stateids);
         stp->st_stateowner = &lo->lo_owner;
         get_nfs4_file(fp);
@@ -4417,6 +4429,9 @@ alloc_init_lock_stateid(struct nfs4_lockowner *lo, struct nfs4_file *fp, struct
         stp->st_deny_bmap = open_stp->st_deny_bmap;
         stp->st_openstp = open_stp;
         list_add(&stp->st_locks, &open_stp->st_locks);
+        spin_lock(&fp->fi_lock);
+        list_add(&stp->st_perfile, &fp->fi_stateids);
+        spin_unlock(&fp->fi_lock);
         return stp;
 }
 
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 06d1a908a58e..04737b3ed363 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -377,6 +377,7 @@ static inline struct nfs4_lockowner * lockowner(struct nfs4_stateowner *so)
 /* nfs4_file: a file opened by some number of (open) nfs4_stateowners. */
 struct nfs4_file {
         atomic_t                fi_ref;
+        spinlock_t              fi_lock;
         struct hlist_node       fi_hash;    /* hash by "struct inode *" */
         struct list_head        fi_stateids;
         struct list_head        fi_delegations;