Commit 57c32ea4 authored Oct 16, 2019 by Chengguang Xu Committed by Theodore Ts'o Jan 25, 2020

ext4: choose hardlimit when softlimit is larger than hardlimit in ext4_statfs_project()



Setting softlimit larger than hardlimit seems meaningless
for disk quota but currently it is allowed. In this case,
there may be a bit of comfusion for users when they run
df comamnd to directory which has project quota.

For example, we set 20M softlimit and 10M hardlimit of
block usage limit for project quota of test_dir(project id 123).

[root@hades mnt_ext4]# repquota -P -a
*** Report for project quotas on device /dev/loop0
Block grace time: 7days; Inode grace time: 7days
                        Block limits                File limits
Project         used    soft    hard  grace    used  soft  hard  grace
----------------------------------------------------------------------
 0        --      13       0       0              2     0     0
 123      --   10237   20480   10240              5   200   100

The result of df command as below:

[root@hades mnt_ext4]# df -h test_dir
Filesystem      Size  Used Avail Use% Mounted on
/dev/loop0       20M   10M   10M  50% /home/cgxu/test/mnt_ext4

Even though it looks like there is another 10M free space to use,
if we write new data to diretory test_dir(inherit project id),
the write will fail with errno(-EDQUOT).

After this patch, the df result looks like below.

[root@hades mnt_ext4]# df -h test_dir
Filesystem      Size  Used Avail Use% Mounted on
/dev/loop0       10M   10M  3.0K 100% /home/cgxu/test/mnt_ext4

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191016022501.760-1-cgxu519@mykernel.net


Signed-off-by: Theodore Ts'o <tytso@mit.edu>

parent ec772f01

fs/ext4/super.c

+17 −6

Original line number	Diff line number	Diff line
		@@ -5585,9 +5585,15 @@ static int ext4_statfs_project(struct super_block *sb,
		return PTR_ERR(dquot);
		spin_lock(&dquot->dq_dqb_lock);

		limit = (dquot->dq_dqb.dqb_bsoftlimit ?
		dquot->dq_dqb.dqb_bsoftlimit :
		dquot->dq_dqb.dqb_bhardlimit) >> sb->s_blocksize_bits;
		limit = 0;
		if (dquot->dq_dqb.dqb_bsoftlimit &&
		(!limit \|\| dquot->dq_dqb.dqb_bsoftlimit < limit))
		limit = dquot->dq_dqb.dqb_bsoftlimit;
		if (dquot->dq_dqb.dqb_bhardlimit &&
		(!limit \|\| dquot->dq_dqb.dqb_bhardlimit < limit))
		limit = dquot->dq_dqb.dqb_bhardlimit;
		limit >>= sb->s_blocksize_bits;

		if (limit && buf->f_blocks > limit) {
		curblock = (dquot->dq_dqb.dqb_curspace +
		dquot->dq_dqb.dqb_rsvspace) >> sb->s_blocksize_bits;
		@@ -5597,9 +5603,14 @@ static int ext4_statfs_project(struct super_block *sb,
		(buf->f_blocks - curblock) : 0;
		}

		limit = dquot->dq_dqb.dqb_isoftlimit ?
		dquot->dq_dqb.dqb_isoftlimit :
		dquot->dq_dqb.dqb_ihardlimit;
		limit = 0;
		if (dquot->dq_dqb.dqb_isoftlimit &&
		(!limit \|\| dquot->dq_dqb.dqb_isoftlimit < limit))
		limit = dquot->dq_dqb.dqb_isoftlimit;
		if (dquot->dq_dqb.dqb_ihardlimit &&
		(!limit \|\| dquot->dq_dqb.dqb_ihardlimit < limit))
		limit = dquot->dq_dqb.dqb_ihardlimit;

		if (limit && buf->f_files > limit) {
		buf->f_files = limit;
		buf->f_ffree =

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