NFSv4: Close another NFSv4 recovery race

State recovery currently relies on being able to find a valid
nfs_open_context in the inode->open_files list.
We therefore need to put the nfs_open_context on the list while
we're still protected by the sp->so_reclaim_seqcount in order
to avoid reboot races.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 18 insertions, 6 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index c1c7a9d78722..c121982659a2 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -713,16 +713,23 @@ EXPORT_SYMBOL_GPL(put_nfs_open_context);
  * Ensure that mmap has a recent RPC credential for use when writing out
  * shared pages
  */
-void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx)
+void nfs_inode_attach_open_context(struct nfs_open_context *ctx)
 {
-        struct inode *inode = file_inode(filp);
+        struct inode *inode = ctx->dentry->d_inode;
         struct nfs_inode *nfsi = NFS_I(inode);
 
-        filp->private_data = get_nfs_open_context(ctx);
         spin_lock(&inode->i_lock);
         list_add(&ctx->list, &nfsi->open_files);
         spin_unlock(&inode->i_lock);
 }
+EXPORT_SYMBOL_GPL(nfs_inode_attach_open_context);
+
+void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx)
+{
+        filp->private_data = get_nfs_open_context(ctx);
+        if (list_empty(&ctx->list))
+                nfs_inode_attach_open_context(ctx);
+}
 EXPORT_SYMBOL_GPL(nfs_file_set_open_context);
 
 /*
@@ -748,10 +755,11 @@ struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_c
 
 static void nfs_file_clear_open_context(struct file *filp)
 {
-        struct inode *inode = file_inode(filp);
         struct nfs_open_context *ctx = nfs_file_open_context(filp);
 
         if (ctx) {
+                struct inode *inode = ctx->dentry->d_inode;
+
                 filp->private_data = NULL;
                 spin_lock(&inode->i_lock);
                 list_move_tail(&ctx->list, &NFS_I(inode)->open_files);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index aaf2c1324be7..65467abbd5a6 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2002,8 +2002,11 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
                 goto out;
 
         ctx->state = state;
-        if (read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
-                nfs4_schedule_stateid_recovery(server, state);
+        if (dentry->d_inode == state->inode) {
+                nfs_inode_attach_open_context(ctx);
+                if (read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
+                        nfs4_schedule_stateid_recovery(server, state);
+        }
 out:
         return ret;
 }
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index fc01d5cb4cf1..1384ed92cad6 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -356,6 +356,7 @@ extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ct
 extern void put_nfs_open_context(struct nfs_open_context *ctx);
 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, fmode_t mode);
 extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode);
+extern void nfs_inode_attach_open_context(struct nfs_open_context *ctx);
 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
 extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx);
 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);