[PATCH AUTOSEL 5.4 10/22] xfs: fix inode quota reservation checks

[PATCH AUTOSEL 5.4 10/22] xfs: fix inode quota reservation checks

[Sasha Levin]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

[ Upstream commit f959b5d037e71a4d69b5bf71faffa065d9269b4a ]

xfs_trans_dqresv is the function that we use to make reservations
against resource quotas.  Each resource contains two counters: the
q_core counter, which tracks resources allocated on disk; and the dquot
reservation counter, which tracks how much of that resource has either
been allocated or reserved by threads that are working on metadata
updates.

For disk blocks, we compare the proposed reservation counter against the
hard and soft limits to decide if we're going to fail the operation.
However, for inodes we inexplicably compare against the q_core counter,
not the incore reservation count.

Since the q_core counter is always lower than the reservation count and
we unlock the dquot between reservation and transaction commit, this
means that multiple threads can reserve the last inode count before we
hit the hard limit, and when they commit, we'll be well over the hard
limit.

Fix this by checking against the incore inode reservation counter, since
we would appear to maintain that correctly (and that's what we report in
GETQUOTA).

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/xfs/xfs_trans_dquot.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
index 16457465833ba..904780dd74aa3 100644
--- a/fs/xfs/xfs_trans_dquot.c
+++ b/fs/xfs/xfs_trans_dquot.c
@@ -646,7 +646,7 @@ xfs_trans_dqresv(
 			}
 		}
 		if (ninos > 0) {
-			total_count = be64_to_cpu(dqp->q_core.d_icount) + ninos;
+			total_count = dqp->q_res_icount + ninos;
 			timer = be32_to_cpu(dqp->q_core.d_itimer);
 			warns = be16_to_cpu(dqp->q_core.d_iwarns);
 			warnlimit = dqp->q_mount->m_quotainfo->qi_iwarnlimit;
-- 
2.25.1

[PATCH AUTOSEL 5.4 20/22] xfs: Fix UBSAN null-ptr-deref in xfs_sysfs_init

[Sasha Levin]

From: Eiichi Tsukata <devel@etsukata.com>

[ Upstream commit 96cf2a2c75567ff56195fe3126d497a2e7e4379f ]

If xfs_sysfs_init is called with parent_kobj == NULL, UBSAN
shows the following warning:

  UBSAN: null-ptr-deref in ./fs/xfs/xfs_sysfs.h:37:23
  member access within null pointer of type 'struct xfs_kobj'
  Call Trace:
   dump_stack+0x10e/0x195
   ubsan_type_mismatch_common+0x241/0x280
   __ubsan_handle_type_mismatch_v1+0x32/0x40
   init_xfs_fs+0x12b/0x28f
   do_one_initcall+0xdd/0x1d0
   do_initcall_level+0x151/0x1b6
   do_initcalls+0x50/0x8f
   do_basic_setup+0x29/0x2b
   kernel_init_freeable+0x19f/0x20b
   kernel_init+0x11/0x1e0
   ret_from_fork+0x22/0x30

Fix it by checking parent_kobj before the code accesses its member.

Signed-off-by: Eiichi Tsukata <devel@etsukata.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: minor whitespace edits]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/xfs/xfs_sysfs.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_sysfs.h b/fs/xfs/xfs_sysfs.h
index e9f810fc67317..43585850f1546 100644
--- a/fs/xfs/xfs_sysfs.h
+++ b/fs/xfs/xfs_sysfs.h
@@ -32,9 +32,11 @@ xfs_sysfs_init(
 	struct xfs_kobj		*parent_kobj,
 	const char		*name)
 {
+	struct kobject		*parent;
+
+	parent = parent_kobj ? &parent_kobj->kobject : NULL;
 	init_completion(&kobj->complete);
-	return kobject_init_and_add(&kobj->kobject, ktype,
-				    &parent_kobj->kobject, "%s", name);
+	return kobject_init_and_add(&kobj->kobject, ktype, parent, "%s", name);
 }
 
 static inline void
-- 
2.25.1