reiserfs_write_full_page should not get_block past eof
PATCH 1/1 reiserfs_write_full_page should not get_block past eof
From: [email protected]
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 <[email protected]>
fs/reiserfs/inode.c +12 -2
@@ -2350,6 +2350,7 @@ static int reiserfs_write_full_page(struunsigned 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