Re: [PATCH v2 1/2] ext4: turning quotas off if mount failed after enable quotas

[Baokun Li]

On 2023/3/27 17:05, Jan Kara wrote:
> On Mon 27-03-23 10:27:02, Baokun Li wrote:
> > 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@xxxxxxxxxx
> > Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
> > Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
> Looks good. Just one comment:
>
> > +failed_mount10:
> > +#ifdef CONFIG_QUOTA
> > +	ext4_quota_off_umount(sb);
> >   failed_mount9:
> > +#endif  /* CONFIG_QUOTA */
> How about dealing with this using __maybe_unused attribute instead. Like:
>
> failed_mount9: __maybe_unused
>
> That would be much easier to read...
>
> 								Honza

Indeed!

Thank you very much for the review!

I will send a patch V3 with the changes suggested by you.
--
With Best Regards,
Baokun Li
.