On Mon 21-09-15 19:02:30, Dongsheng Yang wrote: > On 09/21/2015 05:44 PM, Jan Kara wrote: > >On Mon 21-09-15 17:16:49, Dongsheng Yang wrote: > >>On 09/21/2015 05:13 PM, Jan Kara wrote: > >>>On Mon 21-09-15 12:35:01, Dongsheng Yang wrote: > >>>>On 09/18/2015 07:20 PM, Jan Kara wrote: > >>>>>>.... TBH, there is a little different with other filesystems. I did not > >>>>>>use the "disk" space, but the file space in ubifs quota, although dquot > >>>>>>means disk quota. Same with btrfs quota. If we use disk space for quota, > >>>>>>the most common problem from user is that: why I did not reach the limit > >>>>>>but I can not write any byte. COW in btrfs or out-place-updating in > >>>>>>ubifs makes this problem much worse. > >>>>>> > >>>>>>So I choose file space here for ubifs. > >>>>> > >>>>>OK, so these are really two separate questions. I understand your choice of > >>>>>using file space as the amount of space to account for quota purposes and > >>>>>I'm fine with that choice. Another thing is that regardless of how you > >>>>>decide to do quota accounting, you must maintain i_blocks / i_bytes to > >>>>>contain proper value because dquot_transfer() uses that information to update > >>>>>quota usage when inode owner is changed. > >>>> > >>>>But if we don't use i_blocks to get qsize, what we care only in > >>>>dquot_transter() is dquot->dq_dqb. That means, even if the i_blocks > >>>>is not correct in dquot_transfer() in ubifs, that's okey, because we > >>>>will never use this value, right? > >>> > >>>dquot_transfer() will use the value - when file F changes owner from user A > >>>to user B, then you need to decrement amount of space used by F from A's > >>>quota usage and add that amount to B's quota usage. And the amount of space > >>>is obtained via inode_get_bytes() which uses i_blocks and i_bytes. See > >>>__dquot_transfer() in fs/quota/dquot.c for details. > >> > >>Yes, I see it. But if ubifs doesn't use i_blocks and i_bytes to stand > >>for quota size, as I mentioned I want to use i_size. Then we will never > >>use i_blocks. So we only need a to transfer dquot->dq_dqb values. That > >>means, even the i_blocks in dquot_transfer() is not correct, we don't > >>care it. we only need to make sure values in dquot_dq_dqb are > >>transfered, such as dquot->dq_dqb->curspace for user B is equal with > >>i_size. > > > >I think you are missing one thing: > > > >Assume user A has files F1 (1MB) F2 (2MB) F3 (3MB). > >User B has one file G1 (4MB). > > > >So user A uses 6 MB in total (stored in dquot for user A in dqb_curspace > >field). User B uses 4MB. > > > >Now you do "chown B F1" > > > >You need to change dq_dqb of F1 to point to user B quota structure as you > >explain, that is correct. However you also need to subtract 1MB from user > >A's total usage (which is stored in struct dquot for user A) since file F1 > >no longer belongs to him. And you need to add 1 MB to user B's total usage. > > > >After this user A will have total usage of 5 MB and user B has usage of 5 > >MB as well. You need to properly update the total usage of each user so > >that you can check the usage against quota limits. > > But that's all done in dquot_transfer(). It dquot_decr_space(from) and > dquot_incr_space(to). Let me show the test result in my implementation. Yes, dquot_decr_space(transfer_from[cnt], cur_space) and dquot_incr_space(transfer_to[cnt], cur_space) are the functions changing usage. However have a look at what cur_space is. It is set as: cur_space = inode_get_bytes(inode); and inode_get_bytes() is: ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; So for dquot_transfer() to work correctly, filesystem has to properly maintain i_blocks and i_bytes. > (1). root -> 1M/2M/3M yds ->4M > > [root@atest-guest linux_compile]# ll -h /mnt/ubifs/ > total 11M > -rw-r--r--. 1 root root 1.0M Sep 21 15:54 1M > -rw-r--r--. 1 root root 2.0M Sep 21 15:54 2M > -rw-r--r--. 1 root root 3.0M Sep 21 15:54 3M > -rw-r--r--. 1 yds root 4.0M Sep 21 15:55 4M > -rw-------. 1 root root 6.0K Sep 21 15:53 aquota.group > -rw-------. 1 root root 7.0K Sep 21 15:53 aquota.user > [root@atest-guest linux_compile]# repquota -u /mnt/ubifs/ > *** Report for user quotas on device /dev/ubi0_0 > Block grace time: 7days; Inode grace time: 7days > Block limits File limits > User used soft hard grace used soft hard grace > ---------------------------------------------------------------------- > root -- 6144 0 0 4 0 0 > yds -- 4096 0 0 1 0 0 > > > (2). chown yds /mnt/ubifs/1M > [root@atest-guest linux_compile]# chown yds /mnt/ubifs/1M > [root@atest-guest linux_compile]# ll -h /mnt/ubifs/ > total 11M > -rw-r--r--. 1 yds root 1.0M Sep 21 15:54 1M > -rw-r--r--. 1 root root 2.0M Sep 21 15:54 2M > -rw-r--r--. 1 root root 3.0M Sep 21 15:54 3M > -rw-r--r--. 1 yds root 4.0M Sep 21 15:55 4M > -rw-------. 1 root root 6.0K Sep 21 15:53 aquota.group > -rw-------. 1 root root 7.0K Sep 21 15:53 aquota.user > [root@atest-guest linux_compile]# repquota -u /mnt/ubifs/ > *** Report for user quotas on device /dev/ubi0_0 > Block grace time: 7days; Inode grace time: 7days > Block limits File limits > User used soft hard grace used soft hard grace > ---------------------------------------------------------------------- > root -- 5120 0 0 3 0 0 > yds -- 5120 0 0 2 0 0 > > > (3). quotacheck and check again. > [root@atest-guest linux_compile]# quotaoff /mnt/ubifs && quotacheck > -u /mnt/ubifs/ > [root@atest-guest linux_compile]# ll -h /mnt/ubifs > total 11M > -rw-r--r--. 1 yds root 1.0M Sep 21 15:54 1M > -rw-r--r--. 1 root root 2.0M Sep 21 15:54 2M > -rw-r--r--. 1 root root 3.0M Sep 21 15:54 3M > -rw-r--r--. 1 yds root 4.0M Sep 21 15:55 4M > -rw-------. 1 root root 6.0K Sep 21 15:53 aquota.group > -rw-------. 1 root root 7.0K Sep 21 16:00 aquota.user > [root@atest-guest linux_compile]# repquota -u /mnt/ubifs/ > *** Report for user quotas on device /dev/ubi0_0 > Block grace time: 7days; Inode grace time: 7days > Block limits File limits > User used soft hard grace used soft hard grace > ---------------------------------------------------------------------- > root -- 5120 0 0 3 0 0 > yds -- 5120 0 0 2 0 0 Yes, this case is working because quota code updated i_blocks properly when creating files. But if you do not set i_blocks when reading inodes (which seems to be the case) I expect the following would not work: mount -t ubifs -o usrjquota=aquota.user,jqfmt=vfsv0 <dev> /mnt quotacheck -vu /mnt quotaon -vu /mnt dd if=/dev/zero of=file1 bs=1M count=1 # Umount fs to prune cached information umount /mnt mount -t ubifs -o usrjquota=aquota.user,jqfmt=vfsv0 <dev> /mnt quotaon -vu /mnt chown yds /mnt/file1 repquota -u /mnt/ Now unless you set i_blocks when reading inode, yds would not be accounted for 1 MB /mnt/file1 is using... Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
