Merge branch 'cow_readahead' of git://oss.oracle.com/git/tma/linux-2.6 into merge-2

[mirror_ubuntu-artful-kernel.git] / fs / ocfs2 / mmap.c

diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index b04d6961c0d4d29dfd1394496fea37665746dcd4..7e32db9c2c993b38e67f5d1282525f0a089b54b0 100644 (file)
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -75,9 +75,11 @@ static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
        /*
         * Another node might have truncated while we were waiting on
         * cluster locks.
+        * We don't check size == 0 before the shift. This is borrowed
+        * from do_generic_file_read.
         */
-       last_index = size >> PAGE_CACHE_SHIFT;
-       if (page->index > last_index) {
+       last_index = (size - 1) >> PAGE_CACHE_SHIFT;
+       if (unlikely(!size || page->index > last_index)) {
                ret = -EINVAL;
                goto out;
        }
@@ -108,7 +110,7 @@ static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
         * because the "write" would invalidate their data.
         */
        if (page->index == last_index)
-               len = size & ~PAGE_CACHE_MASK;
+               len = ((size - 1) & ~PAGE_CACHE_MASK) + 1;
 
        ret = ocfs2_write_begin_nolock(file, mapping, pos, len, 0, &locked_page,
                                       &fsdata, di_bh, page);