9p: Fix possible regressions when ->get_sb fails.

->get_sb can fail causing some badness. this patch fixes
   * clear sb->fs_s_info in kill_sb.
   * deactivate_locked_super() calls kill_sb (v9fs_kill_super) which closes the
     destroys the client, clunks all its fids and closes the v9fs session.
     Attempting to do it twice will cause an oops.

Signed-off-by: Abhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index a9d7d08cfbe8ad7d579e287683f3871ca3023c0b..2495af4ad9a621a04599fa4a36ced1b67086b070 100644 (file)
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -120,7 +120,6 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 
        P9_DPRINTK(P9_DEBUG_VFS, " \n");
 
-       st = NULL;
        v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
        if (!v9ses)
                return -ENOMEM;
@@ -173,10 +172,8 @@ P9_DPRINTK(P9_DEBUG_VFS, " simple set mount, return 0\n");
        simple_set_mnt(mnt, sb);
        return 0;
 
-release_sb:
-       deactivate_locked_super(sb);
-
 free_stat:
+       p9stat_free(st);
        kfree(st);
 
 clunk_fid:
@@ -185,7 +182,12 @@ clunk_fid:
 close_session:
        v9fs_session_close(v9ses);
        kfree(v9ses);
+       return retval;
 
+release_sb:
+       p9stat_free(st);
+       kfree(st);
+       deactivate_locked_super(sb);
        return retval;
 }
 
@@ -207,6 +209,7 @@ static void v9fs_kill_super(struct super_block *s)
 
        v9fs_session_close(v9ses);
        kfree(v9ses);
+       s->s_fs_info = NULL;
        P9_DPRINTK(P9_DEBUG_VFS, "exiting kill_super\n");
 }