[RFC PATCH v2 1/5] locks: consolidate checks for compatible filp->f_mode values in setlk handlers

[Jeff Layton]

Add a wrapper around assign_type that does this instead of duplicating
this check in two places. This also fixes a minor wart in the code where
we continue referring to the struct flock after converting it to struct
file_lock.

Signed-off-by: Jeff Layton <jlay...@redhat.com>
---
 fs/locks.c | 61 +++++++++++++++++++++++++------------------------------------
 1 file changed, 25 insertions(+), 36 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 92a0f0a..a387ef7 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -344,6 +344,29 @@ static int assign_type(struct file_lock *fl, long type)
        return 0;
 }
 
+static int posix_assign_type(struct file_lock *fl, long type)
+{
+       int err;
+
+       err = assign_type(fl, type);
+       if (err)
+               return err;
+
+       /* Ensure that fl->fl_filp has compatible f_mode */
+       switch (fl->fl_type) {
+       case F_RDLCK:
+               if (!(fl->fl_file->f_mode & FMODE_READ))
+                       return -EBADF;
+               break;
+       case F_WRLCK:
+               if (!(fl->fl_file->f_mode & FMODE_WRITE))
+                       return -EBADF;
+               break;
+       }
+
+       return 0;
+}
+
 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
  * style lock.
  */
@@ -393,7 +416,7 @@ static int flock_to_posix_lock(struct file *filp, struct 
file_lock *fl,
        fl->fl_ops = NULL;
        fl->fl_lmops = NULL;
 
-       return assign_type(fl, l->l_type);
+       return posix_assign_type(fl, l->l_type);
 }
 
 #if BITS_PER_LONG == 32
@@ -439,7 +462,7 @@ static int flock64_to_posix_lock(struct file *filp, struct 
file_lock *fl,
        fl->fl_ops = NULL;
        fl->fl_lmops = NULL;
 
-       return assign_type(fl, l->l_type);
+       return posix_assign_type(fl, l->l_type);
 }
 #endif
 
@@ -2016,23 +2039,6 @@ again:
                file_lock->fl_flags |= FL_SLEEP;
        }
        
-       error = -EBADF;
-       switch (flock.l_type) {
-       case F_RDLCK:
-               if (!(filp->f_mode & FMODE_READ))
-                       goto out;
-               break;
-       case F_WRLCK:
-               if (!(filp->f_mode & FMODE_WRITE))
-                       goto out;
-               break;
-       case F_UNLCK:
-               break;
-       default:
-               error = -EINVAL;
-               goto out;
-       }
-
        error = do_lock_file_wait(filp, cmd, file_lock);
 
        /*
@@ -2134,23 +2140,6 @@ again:
                file_lock->fl_flags |= FL_SLEEP;
        }
        
-       error = -EBADF;
-       switch (flock.l_type) {
-       case F_RDLCK:
-               if (!(filp->f_mode & FMODE_READ))
-                       goto out;
-               break;
-       case F_WRLCK:
-               if (!(filp->f_mode & FMODE_WRITE))
-                       goto out;
-               break;
-       case F_UNLCK:
-               break;
-       default:
-               error = -EINVAL;
-               goto out;
-       }
-
        error = do_lock_file_wait(filp, cmd, file_lock);
 
        /*
-- 
1.8.3.1

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