[PATCH] ext4: report sub-block project quotas in statfs

[Hungyu Lin <dennylin0707@gmail.com>]

ext4_statfs_project() converts the selected space limit from bytes to
filesystem blocks before checking whether it is nonzero. A nonzero quota
smaller than one block therefore skips the project space adjustments.

For example, a valid 1 KiB hard limit on a 4 KiB-block filesystem leaves
statvfs() and df reporting the underlying filesystem's space, even when
unprivileged data allocation fails with EDQUOT.

Test the byte limit before converting it to filesystem blocks. The
resulting zero block limit then clamps the project space statistics to
zero. Keep the existing rounding and the rule that a zero byte limit
means no quota.

Fixes: 689c958cbe6b ("ext4: add project quota support")
Signed-off-by: Hungyu Lin <dennylin0707@gmail.com>
---
 fs/ext4/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9cae52471dee..91c1a54730f6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -7001,11 +7001,11 @@ static int ext4_statfs_project(struct super_block *sb,
 
 	limit = min_not_zero(dquot->dq_dqb.dqb_bsoftlimit,
 			     dquot->dq_dqb.dqb_bhardlimit);
-	limit >>= sb->s_blocksize_bits;
 
 	if (limit) {
 		uint64_t	remaining = 0;
 
+		limit >>= sb->s_blocksize_bits;
 		curblock = (dquot->dq_dqb.dqb_curspace +
 			    dquot->dq_dqb.dqb_rsvspace) >> sb->s_blocksize_bits;
 		if (limit > curblock)
-- 
2.43.0