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[PATCH] reiserfs_write_full_page() should not get_block past eof

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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@suse.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Chris Mason 2006-08-05 12:15:10 -07:00 committed by Linus Torvalds
parent b5f3953c10
commit b4c76fa721
1 changed files with 12 additions and 2 deletions
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14
fs/reiserfs/inode.c
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@ -2340,6 +2340,7 @@ static int reiserfs_write_full_page(struct page *page,
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;
@ -2387,10 +2388,19 @@ static int reiserfs_write_full_page(struct page *page,
}
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