From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miao Xie Subject: [PATCH 3/3] btrfs: fix panic caused by direct IO Date: Wed, 17 Nov 2010 12:23:35 +0800 Message-ID: <4CE358C7.3040902@cn.fujitsu.com> Reply-To: miaox@cn.fujitsu.com Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 Cc: Linux Btrfs , Linux Kernel , Linux Fsdevel , Andrew Morton , Ito To: Josef Bacik , Chris Mason Return-path: List-ID: btrfs paniced when we write >64KB data by direct IO at one time. Reproduce steps: # mkfs.btrfs /dev/sda5 /dev/sda6 # mount /dev/sda5 /mnt # dd if=/dev/zero of=/mnt/tmpfile bs=100K count=1 oflag=direct Then btrfs paniced: mapping failed logical 1103155200 bio len 69632 len 12288 ------------[ cut here ]------------ kernel BUG at fs/btrfs/volumes.c:3010! [SNIP] Pid: 1992, comm: btrfs-worker-0 Not tainted 2.6.37-rc1 #1 D2399/PRIMERGY RIP: 0010:[] [] btrfs_map_bio+0x202/0x210 [btrfs] [SNIP] Call Trace: [] __btrfs_submit_bio_done+0x1b/0x20 [btrfs] [] run_one_async_done+0x9f/0xb0 [btrfs] [] run_ordered_completions+0x80/0xc0 [btrfs] [] worker_loop+0x154/0x5f0 [btrfs] [] ? worker_loop+0x0/0x5f0 [btrfs] [] ? worker_loop+0x0/0x5f0 [btrfs] [] kthread+0x96/0xa0 [] kernel_thread_helper+0x4/0x10 [] ? kthread+0x0/0xa0 [] ? kernel_thread_helper+0x0/0x10 We fix this problem by adding a function to check the end of the bio span the chunks/stripes or not when we want to add a page into the bios. Reported-by: Tsutomu Itoh Signed-off-by: Miao Xie Tested-by: Tsutomu Itoh --- fs/btrfs/inode.c | 16 +++++++++++++++- 1 files changed, 15 insertions(+), 1 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 32b68fa..341d080 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5689,6 +5689,20 @@ static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw, return 0; } +/* + * This function is used to check the chunk tree when doing direct IO because + * btrfs can't create bios that span stripes or chunks. + */ +static int btrfs_can_merge_page_dio(size_t size, struct inode *inode, + struct bio *bio) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_mapping_tree *map_tree; + + map_tree = &root->fs_info->mapping_tree; + return __btrfs_can_merge_page_to_bio(map_tree, size, bio); +} + static void btrfs_submit_direct(int rw, struct bio *bio, struct inode *inode, loff_t file_offset) { @@ -5873,7 +5887,7 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb, ret = __blockdev_direct_IO(rw, iocb, inode, BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev, iov, offset, nr_segs, btrfs_get_blocks_direct, NULL, - btrfs_submit_direct, NULL, 0); + btrfs_submit_direct, btrfs_can_merge_page_dio, 0); if (ret < 0 && ret != -EIOCBQUEUED) { clear_extent_bit(&BTRFS_I(inode)->io_tree, offset, -- 1.7.0.1