From: mason@xxxxxxxx
Subject: reiserfs_write_full_page should not get_block past eof
reiserfs_write_full_page does zero bytes in the file past eof, but it may
call get_block on those buffers as well. On machines where the page size
is larger than the blocksize, this can result in mmaped files incorrectly
growing up to a block boundary during writepage.
The fix is to avoid calling get_block for any blocks that are entirely past eof
Signed-off-by: Chris Mason <mason@xxxxxxxx>
--- a/fs/reiserfs/inode.c Mon May 08 14:36:37 2006 -0400
+++ b/fs/reiserfs/inode.c Mon May 08 15:37:35 2006 -0400
@@ -2350,6 +2350,7 @@ static int reiserfs_write_full_page(stru
unsigned long end_index = inode->i_size >> PAGE_CACHE_SHIFT;
int error = 0;
unsigned long block;
+ sector_t last_block;
struct buffer_head *head, *bh;
int partial = 0;
int nr = 0;
@@ -2397,10 +2398,19 @@ static int reiserfs_write_full_page(stru
}
bh = head;
block = page->index << (PAGE_CACHE_SHIFT - s->s_blocksize_bits);
+ last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
/* first map all the buffers, logging any direct items we find */
do {
- if ((checked || buffer_dirty(bh)) && (!buffer_mapped(bh) ||
- (buffer_mapped(bh)
+ if (block > last_block) {
+ /*
+ * This can happen when the block size is less than
+ * the page size. The corresponding bytes in the page
+ * were zero filled above
+ */
+ clear_buffer_dirty(bh);
+ set_buffer_uptodate(bh);
+ } else if ((checked || buffer_dirty(bh)) &&
+ (!buffer_mapped(bh) || (buffer_mapped(bh)
&& bh->b_blocknr ==
0))) {
/* not mapped yet, or it points to a direct item, search
--
-
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