----- Original Message -----
> Summary:
> there exists a wrong return value of function gfs2_set_dqblk().
>
> Bug Description:
>
> In function gfs2_set_dqblk() at fs/gfs2/quota.c：1524, the call to
> gfs2_alloc_get() in line 1599 may return a NULL pointer, and thus
> function gfs2_set_dqblk() will return the value of variable error. And,
> the function gfs2_set_dqblk() will return 0 at last when it runs well.
> However, when the call to gfs2_alloc_get() in line 1599 return a NULL
> pointer, the value of error is 0. So the function gfs2_set_dqblk() will
> return 0 to its caller functions when it runs error because of the
> failing call to gfs2_alloc_get(), leading to a wrong return value of
> function gfs2_set_dqblk().
> The related code snippets in gfs2_set_dqblk() is as following.
> gfs2_set_dqblk @@fs/gfs2/quota.c：1524
> 1524 static int gfs2_set_dqblk(struct super_block *sb, int type, qid_t id,
> 1525 struct fs_disk_quota *fdq)
> 1526 {
> ...
> 1573 /* Check for existing entry, if none then alloc new blocks */
> 1574 error = update_qd(sdp, qd);
> 1575 if (error)
> 1576 goto out_i;
> ...
> 1598 if (alloc_required) {
> 1599 al = gfs2_alloc_get(ip);
> 1600 if (al == NULL)
> 1601 goto out_i;
> 1602 gfs2_write_calc_reserv(ip, sizeof(struct gfs2_quota),
> 1603 &data_blocks, &ind_blocks);
> 1604 blocks = al->al_requested = 1 + data_blocks +
> ind_blocks;
> 1605 error = gfs2_inplace_reserve(ip);
> 1606 if (error)
> 1607 goto out_alloc;
> 1608 blocks += gfs2_rg_blocks(al);
> 1609 }
> 1610
> 1611 /* Some quotas span block boundaries and can update two blocks,
> 1612 adding an extra block to the transaction to handle such
> quotas */
> 1613 error = gfs2_trans_begin(sdp, blocks + RES_DINODE + 2, 0);
> 1614 if (error)
> 1615 goto out_release;
> ...
> 1627 out_i:
> 1628 gfs2_glock_dq_uninit(&i_gh);
> 1629 out_q:
> 1630 gfs2_glock_dq_uninit(&q_gh);
> 1631 out_put:
> 1632 mutex_unlock(&ip->i_inode.i_mutex);
> 1633 qd_put(qd);
> 1634 return error;
> 1635 }
>
> Generally, the return value of caller functions which call function
> gfs2_alloc_get() shall be set to -ENOMEM when the call to gfs2_alloc_get()
> returns a NULL pointer, like the following codes in another file.
> leaf_dealloc @@fs/gfs2/dir.c: 1857
> 1857 static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len,
> 1858 u64 leaf_no, void *data)
> 1859 {
> ...
> 1876 if (!gfs2_alloc_get(dip)) {
> 1877 error = -ENOMEM;
> 1878 goto out;
> 1879 }
> ...
> 1959 out:
> 1960 kfree(ht);
> 1961 return error;
> 1962 }
>
> Kernel version:
> 2.6.39
Hi,
2.6.39 is a very old kernel and the newer code has changed a lot since then.
If this is a problem in RHEL6, you should contact Red Hat's GSS support to
get help. If this is a problem on Centos or other, I recommend moving to a
newer kernel to see if the problem has already been fixed.
Regards,
Bob Peterson
Red Hat File Systems
