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linux/fs/quota
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Ye Bin d6a95db3c7 quota: fix warning in dqgrab() 
There's issue as follows when do fault injection:
WARNING: CPU: 1 PID: 14870 at include/linux/quotaops.h:51 dquot_disable+0x13b7/0x18c0
Modules linked in:
CPU: 1 PID: 14870 Comm: fsconfig Not tainted 6.3.0-next-20230505-00006-g5107a9c821af-dirty #541
RIP: 0010:dquot_disable+0x13b7/0x18c0
RSP: 0018:ffffc9000acc79e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88825e41b980
RDX: 0000000000000000 RSI: ffff88825e41b980 RDI: 0000000000000002
RBP: ffff888179f68000 R08: ffffffff82087ca7 R09: 0000000000000000
R10: 0000000000000001 R11: ffffed102f3ed026 R12: ffff888179f68130
R13: ffff888179f68110 R14: dffffc0000000000 R15: ffff888179f68118
FS:  00007f450a073740(0000) GS:ffff88882fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe96f2efd8 CR3: 000000025c8ad000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dquot_load_quota_sb+0xd53/0x1060
 dquot_resume+0x172/0x230
 ext4_reconfigure+0x1dc6/0x27b0
 reconfigure_super+0x515/0xa90
 __x64_sys_fsconfig+0xb19/0xd20
 do_syscall_64+0x39/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Above issue may happens as follows:
ProcessA              ProcessB                    ProcessC
sys_fsconfig
  vfs_fsconfig_locked
   reconfigure_super
     ext4_remount
      dquot_suspend -> suspend all type quota

                 sys_fsconfig
                  vfs_fsconfig_locked
                    reconfigure_super
                     ext4_remount
                      dquot_resume
                       ret = dquot_load_quota_sb
                        add_dquot_ref
                                           do_open  -> open file O_RDWR
                                            vfs_open
                                             do_dentry_open
                                              get_write_access
                                               atomic_inc_unless_negative(&inode->i_writecount)
                                              ext4_file_open
                                               dquot_file_open
                                                dquot_initialize
                                                  __dquot_initialize
                                                   dqget
						    atomic_inc(&dquot->dq_count);

                          __dquot_initialize
                           __dquot_initialize
                            dqget
                             if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
                               ext4_acquire_dquot
			        -> Return error DQ_ACTIVE_B flag isn't set
                         dquot_disable
			  invalidate_dquots
			   if (atomic_read(&dquot->dq_count))
	                    dqgrab
			     WARN_ON_ONCE(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
	                      -> Trigger warning

In the above scenario, 'dquot->dq_flags' has no DQ_ACTIVE_B is normal when
dqgrab().
To solve above issue just replace the dqgrab() use in invalidate_dquots() with
atomic_inc(&dquot->dq_count).

Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230605140731.2427629-3-yebin10@huawei.com>
2023-06-05 16:50:30 +02:00
..
compat.h quota: simplify the quotactl compat handling 2020-09-17 13:00:46 -04:00
dquot.c quota: fix warning in dqgrab() 2023-06-05 16:50:30 +02:00
Kconfig quota: mark PRINT_QUOTA_WARNING as BROKEN 2023-04-14 13:06:50 +02:00
kqid.c
Makefile quota: simplify the quotactl compat handling 2020-09-17 13:00:46 -04:00
netlink.c
quota_tree.c quota: Add more checking after reading from quota file 2022-09-29 15:37:30 +02:00
quota_tree.h
quota_v1.c quota: fixup *_write_file_info() to return proper error code 2023-03-20 17:27:42 +01:00
quota_v2.c quota: fixup *_write_file_info() to return proper error code 2023-03-20 17:27:42 +01:00
quota.c fs: Drop wait_unfrozen wait queue 2023-05-30 15:36:40 +02:00
quotaio_v1.h quota: avoid time_t in v1_disk_dqblk definition 2019-12-16 14:15:30 +01:00
quotaio_v2.h