nfsd: Push mnt_want_write() outside of i_mutex

When mnt_want_write() starts to handle freezing it will get a full lock
semantics requiring proper lock ordering. So push mnt_want_write() call
consistently outside of i_mutex.

CC: linux-nfs@vger.kernel.org
CC: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 5 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 5ff0b7b9fc08..43295d45cc2b 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
         if (status < 0)
                 return;
 
+        status = mnt_want_write_file(rec_file);
+        if (status)
+                return;
+
         dir = rec_file->f_path.dentry;
         /* lock the parent */
         mutex_lock(&dir->d_inode->i_mutex);
@@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
                  * as well be forgiving and just succeed silently.
                  */
                 goto out_put;
-        status = mnt_want_write_file(rec_file);
-        if (status)
-                goto out_put;
         status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
-        mnt_drop_write_file(rec_file);
 out_put:
         dput(dentry);
 out_unlock:
@@ -189,6 +189,7 @@ out_unlock:
                                 " (err %d); please check that %s exists"
                                 " and is writeable", status,
                                 user_recovery_dirname);
+        mnt_drop_write_file(rec_file);
         nfs4_reset_creds(original_cred);
 }