[PATCH v3 1/2] ext4: turning quotas off if mount failed after enable quotas

[Baokun Li <libaokun1@huawei.com>]

Yi found during a review of the patch "ext4: don't BUG on inconsistent
journal feature" that when ext4_mark_recovery_complete() returns an error
value, the error handling path does not turn off the enabled quotas,
which triggers the following kmemleak:

================================================================
unreferenced object 0xffff8cf68678e7c0 (size 64):
comm "mount", pid 746, jiffies 4294871231 (age 11.540s)
hex dump (first 32 bytes):
00 90 ef 82 f6 8c ff ff 00 00 00 00 41 01 00 00  ............A...
c7 00 00 00 bd 00 00 00 0a 00 00 00 48 00 00 00  ............H...
backtrace:
[<00000000c561ef24>] __kmem_cache_alloc_node+0x4d4/0x880
[<00000000d4e621d7>] kmalloc_trace+0x39/0x140
[<00000000837eee74>] v2_read_file_info+0x18a/0x3a0
[<0000000088f6c877>] dquot_load_quota_sb+0x2ed/0x770
[<00000000340a4782>] dquot_load_quota_inode+0xc6/0x1c0
[<0000000089a18bd5>] ext4_enable_quotas+0x17e/0x3a0 [ext4]
[<000000003a0268fa>] __ext4_fill_super+0x3448/0x3910 [ext4]
[<00000000b0f2a8a8>] ext4_fill_super+0x13d/0x340 [ext4]
[<000000004a9489c4>] get_tree_bdev+0x1dc/0x370
[<000000006e723bf1>] ext4_get_tree+0x1d/0x30 [ext4]
[<00000000c7cb663d>] vfs_get_tree+0x31/0x160
[<00000000320e1bed>] do_new_mount+0x1d5/0x480
[<00000000c074654c>] path_mount+0x22e/0xbe0
[<0000000003e97a8e>] do_mount+0x95/0xc0
[<000000002f3d3736>] __x64_sys_mount+0xc4/0x160
[<0000000027d2140c>] do_syscall_64+0x3f/0x90
================================================================

To solve this problem, we add a "failed_mount10" tag, and call
ext4_quota_off_umount() in this tag to release the enabled qoutas.

Fixes: 11215630aada ("ext4: don't BUG on inconsistent journal feature")
Cc: stable@kernel.org
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
V1->V2:
        Add judgment for CONFIG_QUOTA to avoid warning
        "label 'failed_mount9' defined but not used".
        (Reported-by: kernel test robot <lkp@intel.com>)
V2->V3:
        By adding __maybe_unused to silence possible compilation
        complain in patch one, instead of adding the judgment.
        (Suggested by Jan Kara).

 fs/ext4/super.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e6d84c1e34a4..97addf5fd642 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5520,7 +5520,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
 		ext4_msg(sb, KERN_INFO, "recovery complete");
 		err = ext4_mark_recovery_complete(sb, es);
 		if (err)
-			goto failed_mount9;
+			goto failed_mount10;
 	}
 
 	if (test_opt(sb, DISCARD) && !bdev_max_discard_sectors(sb->s_bdev))
@@ -5539,7 +5539,9 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
 
 	return 0;
 
-failed_mount9:
+failed_mount10:
+	ext4_quota_off_umount(sb);
+failed_mount9: __maybe_unused
 	ext4_release_orphan_info(sb);
 failed_mount8:
 	ext4_unregister_sysfs(sb);
-- 
2.31.1