block: clean up blkdev_get() wrappers and their users

After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().

blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.

All users are converted.  Most conversions are mechanical and don't
introduce any behavior difference.  There are several exceptions.

* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
  reason to OR it explicitly on blkdev_put().

* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
  sb->s_mode.

* With the above changes, sb->s_mode now always should contain
  FMODE_EXCL.  WARN_ON_ONCE() added to kill_block_super() to detect
  errors.

The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index fd034609028..650e43ba4f7 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -902,8 +902,8 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
                 }
         }
 
-        bdev = open_bdev_exclusive(nbc->dc.backing_dev,
-                                   FMODE_READ | FMODE_WRITE, mdev);
+        bdev = blkdev_get_by_path(nbc->dc.backing_dev,
+                                  FMODE_READ | FMODE_WRITE | FMODE_EXCL, mdev);
         if (IS_ERR(bdev)) {
                 dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.backing_dev,
                         PTR_ERR(bdev));
@@ -920,10 +920,10 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
          * should check it for you already; but if you don't, or
          * someone fooled it, we need to double check here)
          */
-        bdev = open_bdev_exclusive(nbc->dc.meta_dev,
-                                   FMODE_READ | FMODE_WRITE,
-                                   (nbc->dc.meta_dev_idx < 0) ?
-                                   (void *)mdev : (void *)drbd_m_holder);
+        bdev = blkdev_get_by_path(nbc->dc.meta_dev,
+                                  FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+                                  (nbc->dc.meta_dev_idx < 0) ?
+                                  (void *)mdev : (void *)drbd_m_holder);
         if (IS_ERR(bdev)) {
                 dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.meta_dev,
                         PTR_ERR(bdev));