From 9dd75f1f1a02d656a11a7b9b9e6c2759b9c1e946 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 13 Aug 2011 12:58:21 -0400 Subject: [PATCH] ext4: fix nomblk_io_submit option so it correctly converts uninit blocks Bug discovered by Jan Kara: Finally, commit 1449032be17abb69116dbc393f67ceb8bd034f92 returned back the old IO submission code but apparently it forgot to return the old handling of uninitialized buffers so we unconditionnaly call block_write_full_page() without specifying end_io function. So AFAICS we never convert unwritten extents to written in some cases. For example when I mount the fs as: mount -t ext4 -o nomblk_io_submit,dioread_nolock /dev/ubdb /mnt and do int fd = open(argv[1], O_RDWR | O_CREAT | O_TRUNC, 0600); char buf[1024]; memset(buf, 'a', sizeof(buf)); fallocate(fd, 0, 0, 16384); write(fd, buf, sizeof(buf)); I get a file full of zeros (after remounting the filesystem so that pagecache is dropped) instead of seeing the first KB contain 'a's. Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org --- fs/ext4/inode.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 762e803..c4da98a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1291,7 +1291,12 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd, else if (test_opt(inode->i_sb, MBLK_IO_SUBMIT)) err = ext4_bio_write_page(&io_submit, page, len, mpd->wbc); - else + else if (buffer_uninit(page_bufs)) { + ext4_set_bh_endio(page_bufs, inode); + err = block_write_full_page_endio(page, + noalloc_get_block_write, + mpd->wbc, ext4_end_io_buffer_write); + } else err = block_write_full_page(page, noalloc_get_block_write, mpd->wbc); -- 2.7.4