From: Eric W. Biederman The problem: When we are trying to free buffers try_to_free_buffers will look at ramdisk pages with clean buffer heads and remove the dirty bit from the page. Resulting in ramdisk pages with data that get removed from the page cache. Ouch! When we mark a ramdisk page dirty we call set_page_dirty which then calls ramdisk_set_page_dirty. Currently we don't mark the buffer heads dirty leaving us susceptible to the problem above. So to fix the mismatch between buffer head state and page state this patch modifies ramdisk_set_page_dirty to set the dirty bit on all of the buffers a page may posses. I set the uptodate bit on the buffer head so that later we can use simple_commit_write, and because it is trivially safe. Signed-off-by: Eric W. Biederman Signed-off-by: Andrew Morton --- drivers/block/rd.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff -puN drivers/block/rd.c~rd-mark-ramdisk-buffer-heads-dirty-in-ramdisk_set_page_dirty drivers/block/rd.c --- a/drivers/block/rd.c~rd-mark-ramdisk-buffer-heads-dirty-in-ramdisk_set_page_dirty +++ a/drivers/block/rd.c @@ -184,6 +184,21 @@ static int ramdisk_writepages(struct add */ static int ramdisk_set_page_dirty(struct page *page) { + struct address_space * const mapping = page_mapping(page); + + spin_lock(&mapping->private_lock); + if (page_has_buffers(page)) { + struct buffer_head *head = page_buffers(page); + struct buffer_head *bh = head; + + do { + set_buffer_uptodate(bh); + set_buffer_dirty(bh); + bh = bh->b_this_page; + } while (bh != head); + } + spin_unlock(&mapping->private_lock); + if (!TestSetPageDirty(page)) return 1; return 0; _