GFS2: Get a block reservation before resizing a file

commit d2b47cfb26fe06002b8011707baac71a9ae8166f upstream.

This patch allocates a block reservation structure before growing
or shrinking a file. Without this structure, the grow or shink code
can reference the bad pointer.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index a68e91bcef3ddf7d005665955ecff7909ccb171f..9a3945a7f48fe25f6ebf5562fa1fb9b35395db61 100644 (file)
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1286,6 +1286,10 @@ int gfs2_setattr_size(struct inode *inode, u64 newsize)
 
        inode_dio_wait(inode);
 
+       ret = gfs2_rs_alloc(GFS2_I(inode));
+       if (ret)
+               return ret;
+
        oldsize = inode->i_size;
        if (newsize >= oldsize)
                return do_grow(inode, newsize);