On Thu 28-10-10 03:36:07, Frederic Weisbecker wrote:
> On Thu, Oct 28, 2010 at 02:28:23AM +0200, Jan Kara wrote:
> > reiserfs_quota_on() unpacks a tail of quota file in case it has one. But after
> > BKL conversion, reiserfs_unpack() expects to be called with write_lock held.
> > So acquire the lock before calling reiserfs_unpack() to avoid assertion
> > failures.
> >
> > Reported-by: markus.gapp@xxxxxxx
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > ---
> > fs/reiserfs/super.c | 2 ++
> > 1 files changed, 2 insertions(+), 0 deletions(-)
> >
> > Frederic, would you merge this patch or should I merge it?
> >
> > diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
> > index 6e85cfd..73c000f 100644
> > --- a/fs/reiserfs/super.c
> > +++ b/fs/reiserfs/super.c
> > @@ -2059,7 +2059,9 @@ static int reiserfs_quota_on(struct super_block *sb, int type, int format_id,
> > inode = path->dentry->d_inode;
> > /* We must not pack tails for quota files on reiserfs for quota IO to work */
> > if (!(REISERFS_I(inode)->i_flags & i_nopack_mask)) {
> > + reiserfs_write_lock(sb);
> > err = reiserfs_unpack(inode, NULL);
> > + reiserfs_write_unlock(sb);
> > if (err) {
> > reiserfs_warning(sb, "super-6520",
> > "Unpacking tail of quota file failed"
> > --
> > 1.7.1
> >
>
>
>
> Yeah. This is due to a recent fix in reiserfs_unpack().
> And in this fix I assumed reiserfs_unpack() was always called under the
> reiserfs lock.
> I was wrong, I thought that reiserfs_quota_on() was ok because it can
> call joural_begin() which appears to have the same requirements.
> But no that's probably another bug, journal_begin() should also
> be called under the reiserfs lock.
> Anyway that must be another patch.
>
>
> For this specific problem, it might be slightly more proper to do the
> below. It lowers a bit the reiserfs lock coverage and also fixes
> a weird lock-unlock ordering in reiserfs_unpack() that was doing:
>
> Lock A - Lock B - Unlock A - Unlock B
>
> Hmm?
Looks OK to me. Do you plan to merge it?
Honza
> diff --git a/fs/reiserfs/ioctl.c b/fs/reiserfs/ioctl.c
> index 5cbb81e..af2a58f 100644
> --- a/fs/reiserfs/ioctl.c
> +++ b/fs/reiserfs/ioctl.c
> @@ -189,8 +189,8 @@ int reiserfs_unpack(struct inode *inode, struct file *filp)
> /* we need to make sure nobody is changing the file size beneath
> ** us
> */
> - reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb);
> depth = reiserfs_write_lock_once(inode->i_sb);
> + reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb);
>
> write_from = inode->i_size & (blocksize - 1);
> /* if we are on a block boundary, we are already unpacked. */
>
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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