On Fri, Sep 07, 2012 at 08:01:25PM -0600, Liu Bo wrote:
> Users report a bug, the reproducer is:
> $ mkfs.btrfs /dev/loop0
> $ mount /dev/loop0 /mnt/btrfs/
> $ mkdir /mnt/btrfs/dir
> $ chattr +C /mnt/btrfs/dir/
> $ dd if=/dev/zero of=/mnt/btrfs/dir/foo bs=4K count=10;
> $ lsattr /mnt/btrfs/dir/foo
> ---------------C- /mnt/btrfs/dir/foo
> $ filefrag /mnt/btrfs/dir/foo
> /mnt/btrfs/dir/foo: 1 extent found ---> an extent
> $ dd if=/dev/zero of=/mnt/btrfs/dir/foo bs=4K count=1 seek=5 conv=notrunc,nocreat; sync
> $ filefrag /mnt/btrfs/dir/foo
> /mnt/btrfs/dir/foo: 3 extents found ---> with nocow, btrfs breaks the extent into three parts
>
> The new created file should not only inherit the NODATACOW flag, but also
> honor NODATASUM flag, because we must do COW on a file extent with checksum.
>
> Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
> ---
> v1->v2: add check for only regular file
>
> fs/btrfs/inode.c | 3 +--
> fs/btrfs/ioctl.c | 7 +++++--
> 2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index b2c3514..9bce6e9 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -4720,8 +4720,7 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
> if (S_ISREG(mode)) {
> if (btrfs_test_opt(root, NODATASUM))
> BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
> - if (btrfs_test_opt(root, NODATACOW) ||
> - (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
> + if (btrfs_test_opt(root, NODATACOW))
> BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
> }
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 00ddf22..2fd5455 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -140,8 +140,11 @@ void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
> BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
> }
>
> - if (flags & BTRFS_INODE_NODATACOW)
> - BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
> + if (flags & BTRFS_INODE_NODATACOW) {
> + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
> + if (S_ISREG(inode->i_mode))
> + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
> + }
>
This doesn't compile. Thanks,
Josef
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