You are right, your patch does improve the situation a bit. But it
still does not address the main issue. To illustrate that, consider
the following scenario:
touch test
chattr +C test
head -c 1048576 /dev/zero >> test
mv test test2
now test2 lost the C flag because it was renamed. But the data in
test2 was written before it lost the C flag and so the extents do not
have checksums!
Also try to clone it with BTRFS_IOC_CLONE. It fails as if it had the C flag:
cp --reflink test2 test3
OTOH, if you try to clone over a file with NODATACOW then it works:
touch test3
chattr +C test3
cp --reflink test2 test3
so the file is in an incosistent state: it sometimes behaves as if it
had the NODATACOW flag and sometimes as if it didn't.
Thanks
On Fri, Feb 22, 2013 at 3:40 AM, Liu Bo <bo.li.liu@xxxxxxxxxx> wrote:
> On Fri, Feb 22, 2013 at 03:32:50AM -0500, Marios Titas wrote:
>> Sorry, but the bug persists even with the above patch.
>>
>> touch test
>> chattr +C test
>> lsattr test
>> mv test test2
>> lsattr test2
>>
>> In the above scenario test2 will not have the C flag.
>
> What do you expect? IMO it's right that test2 does not have the C flag.
>
> This patch ensure that we get the same result after we remount, no more
> the C flag coming back :)
>
> thanks,
> liubo
>
>>
>> On Fri, Feb 22, 2013 at 3:11 AM, Liu Bo <bo.li.liu@xxxxxxxxxx> wrote:
>> > A user reported some weird behaviours,
>> > if we move a file with the noCow flag to a directory without the
>> > noCow flag, the file is now without the flag, but after remount,
>> > we'll find the file's noCow flag comes back.
>> >
>> > This is because we missed a proper inode update after inheriting
>> > parent directory's flags,
>> >
>> > Reported-by: Marios Titas <redneb8888@xxxxxxxxx>
>> > Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
>> > ---
>> > fs/btrfs/inode.c | 7 +++++--
>> > 1 files changed, 5 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
>> > index d9984fa..d2e3352 100644
>> > --- a/fs/btrfs/inode.c
>> > +++ b/fs/btrfs/inode.c
>> > @@ -7478,8 +7478,6 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
>> > old_dentry->d_inode,
>> > old_dentry->d_name.name,
>> > old_dentry->d_name.len);
>> > - if (!ret)
>> > - ret = btrfs_update_inode(trans, root, old_inode);
>> > }
>> > if (ret) {
>> > btrfs_abort_transaction(trans, root, ret);
>> > @@ -7514,6 +7512,11 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
>> > }
>> >
>> > fixup_inode_flags(new_dir, old_inode);
>> > + ret = btrfs_update_inode(trans, root, old_inode);
>> > + if (ret) {
>> > + btrfs_abort_transaction(trans, root, ret);
>> > + goto out_fail;
>> > + }
>> >
>> > ret = btrfs_add_link(trans, new_dir, old_inode,
>> > new_dentry->d_name.name,
>> > --
>> > 1.7.7.6
>> >
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