From: Chris Mason Date: Sat, 5 Aug 2006 19:15:10 +0000 (-0700) Subject: [PATCH] reiserfs_write_full_page() should not get_block past eof X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b4c76fa721c7c8a43655a74e508870d21d2e26d3;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git [PATCH] 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c index ac57305b1afc..52f1e2136546 100644 --- a/fs/reiserfs/inode.c +++ b/fs/reiserfs/inode.c @@ -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