wrappers for ->i_mutex access

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 3c68e6a..10c5ae7 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1014,7 +1014,7 @@
 	if (!prealloc_cf)
 		return -ENOMEM;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
@@ -1070,7 +1070,7 @@
 	    (iocb->ki_flags & IOCB_DIRECT) || (fi->flags & CEPH_F_SYNC)) {
 		struct ceph_snap_context *snapc;
 		struct iov_iter data;
-		mutex_unlock(&inode->i_mutex);
+		inode_unlock(inode);
 
 		spin_lock(&ci->i_ceph_lock);
 		if (__ceph_have_pending_cap_snap(ci)) {
@@ -1097,7 +1097,7 @@
 				"got EOLDSNAPC, retrying\n",
 				inode, ceph_vinop(inode),
 				pos, (unsigned)count);
-			mutex_lock(&inode->i_mutex);
+			inode_lock(inode);
 			goto retry_snap;
 		}
 		if (written > 0)
@@ -1117,7 +1117,7 @@
 			iocb->ki_pos = pos + written;
 		if (inode->i_size > old_size)
 			ceph_fscache_update_objectsize(inode);
-		mutex_unlock(&inode->i_mutex);
+		inode_unlock(inode);
 	}
 
 	if (written >= 0) {
@@ -1147,7 +1147,7 @@
 	goto out_unlocked;
 
 out:
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 out_unlocked:
 	ceph_free_cap_flush(prealloc_cf);
 	current->backing_dev_info = NULL;
@@ -1162,7 +1162,7 @@
 	struct inode *inode = file->f_mapping->host;
 	int ret;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 
 	if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) {
 		ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);
@@ -1207,7 +1207,7 @@
 	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
 
 out:
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 	return offset;
 }
 
@@ -1363,7 +1363,7 @@
 	if (!prealloc_cf)
 		return -ENOMEM;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 
 	if (ceph_snap(inode) != CEPH_NOSNAP) {
 		ret = -EROFS;
@@ -1418,7 +1418,7 @@
 
 	ceph_put_cap_refs(ci, got);
 unlock:
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 	ceph_free_cap_flush(prealloc_cf);
 	return ret;
 }