Re: [f2fs-dev] f2fs: f2fs unmount hangs if f2fs_init_acl() fails during mkdir syscall

[Gu Zheng <guz.fnst@cn.fujitsu.com>]

Hi Andrey,
On 02/11/2014 04:29 PM, Andrey Tsyvarev wrote:

> Hi,
> 
>> It turns out that make_bad_inode prior to iput sets i_mode to a regular
>> file, so that f2fs_evict_inode -> truncate_inode_pages ->
>> f2fs_invalidate_data_page doesn't decrement dirty_dents.
>>
> It seems that remove_dirty_dir_inode() call should also be added to the error-path of
> init_inode_metadata, because its functionality is also based on inode->i_mode field
> which is changed by make_bad_inode().

It seems that your opinion is correct. remove_dirty_dir_inode() will not clean up the 
dir_inode_entry because make_bad_inode() sets i_mode to S_IFREG in the fail path of
init_inode_metadata, and it leads to the following "memory leak".

BTW, have you tested the case that added remove_dirty_dir_inode() into the fail path
of init_inode_metadata?
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index e095a4f..d5a2c9e 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -375,6 +375,7 @@ put_error:
        /* once the failed inode becomes a bad inode, i_mode is S_IFREG */
        truncate_inode_pages(&inode->i_data, 0);
        truncate_blocks(inode, 0);
+       remove_dirty_dir_inode(inode);
 error:
        remove_inode_page(inode);
        return ERR_PTR(err);

Regards,
Gu

> 
> Otherwise memory leak is reported when f2fs module is unloaded:
> 
> [  231.378192] BUG f2fs_dirty_dir_entry (Tainted: GF          O): Objects remaining in f2fs_dirty_dir_entry on kmem_cache_close()
> [  231.378193] -----------------------------------------------------------------------------
> 
> [  231.378194] Disabling lock debugging due to kernel taint
> [  231.378195] INFO: Slab 0xffffea0000437200 objects=102 used=1 fp=0xffff880010dc8fc8 flags=0x3fffc000000080
> [  231.378197] CPU: 0 PID: 2605 Comm: rmmod Tainted: GF   B      O 3.14.0-rc1fs #4
> [  231.378198] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
> [  231.378199]  ffff88000e5e3200 ffff88000cc9bd40 ffffffff8166fd7e ffffea0000437200
> [  231.378202]  ffff88000cc9be28 ffffffff811c3fdf ffff88003fc10066 ffffffff0cc9bda0
> [  231.378203]  ffffffff00000020 ffff88000cc9be38 ffff88000cc9bde0 656a624f00000296
> [  231.378205] Call Trace:
> [  231.378210]  [<ffffffff8166fd7e>] dump_stack+0x45/0x56
> [  231.378213]  [<ffffffff811c3fdf>] slab_err+0xaf/0xc0
> [  231.378215]  [<ffffffff811c84a3>] ? kmem_cache_close+0x133/0x340
> [  231.378216]  [<ffffffff811c6b55>] ? __kmalloc+0x1f5/0x250
> [  231.378218]  [<ffffffff811c84c3>] kmem_cache_close+0x153/0x340
> [  231.378221]  [<ffffffff81193417>] ? kmem_cache_destroy+0x27/0xf0
> [  231.378223]  [<ffffffff811c86c4>] __kmem_cache_shutdown+0x14/0x80
> [  231.378224]  [<ffffffff81193431>] kmem_cache_destroy+0x41/0xf0
> [  231.378229]  [<ffffffffa01eab91>] destroy_checkpoint_caches+0x21/0x30 [f2fs]
> [  231.378232]  [<ffffffffa01facda>] exit_f2fs_fs+0x28/0x34e [f2fs]
> [  231.378235]  [<ffffffff810ffe32>] SyS_delete_module+0x152/0x1f0
> [  231.378237]  [<ffffffff8111d85c>] ? __audit_syscall_entry+0x9c/0xf0
> [  231.378239]  [<ffffffff81680729>] system_call_fastpath+0x16/0x1b
> [  231.378242] INFO: Object 0xffff880010dc8000 @offset=0
> [  231.378245] kmem_cache_destroy f2fs_dirty_dir_entry: Slab cache still has objects
> [  231.378247] CPU: 0 PID: 2605 Comm: rmmod Tainted: GF   B      O 3.14.0-rc1fs #4
> [  231.378247] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
> [  231.378248]  ffff88000e5e3268 ffff88000cc9beb8 ffffffff8166fd7e ffff88000e5e3200
> [  231.378250]  ffff88000cc9bed8 ffffffff811934cf 0000000000000000 ffffffffa0204f60
> [  231.378251]  ffff88000cc9bee8 ffffffffa01eab91 ffff88000cc9bef8 ffffffffa01facda
> [  231.378253] Call Trace:
> [  231.378255]  [<ffffffff8166fd7e>] dump_stack+0x45/0x56
> [  231.378256]  [<ffffffff811934cf>] kmem_cache_destroy+0xdf/0xf0
> [  231.378259]  [<ffffffffa01eab91>] destroy_checkpoint_caches+0x21/0x30 [f2fs]
> [  231.378262]  [<ffffffffa01facda>] exit_f2fs_fs+0x28/0x34e [f2fs]
> [  231.378263]  [<ffffffff810ffe32>] SyS_delete_module+0x152/0x1f0
> [  231.378265]  [<ffffffff8111d85c>] ? __audit_syscall_entry+0x9c/0xf0
> [  231.378266]  [<ffffffff81680729>] system_call_fastpath+0x16/0x1b
> 
> 
> Stack of allocation (obtained with KEDR, which is also used for fault simulation):
> 
> [  231.414875] [leak_check] Address: 0xffff880010dc8000, size: 24; stack trace of the allocation:
> [  231.414886] [leak_check] [<ffffffffa01e9d72>] set_dirty_dir_page+0x62/0xe0 [f2fs]
> [  231.414893] [leak_check] [<ffffffffa01ec9be>] f2fs_set_data_page_dirty+0x4e/0x90 [f2fs]
> [  231.414898] [leak_check] [<ffffffff8117b02a>] set_page_dirty+0x3a/0x60
> [  231.414904] [leak_check] [<ffffffffa01dfeb2>] __f2fs_add_link+0x732/0x7d0 [f2fs]
> [  231.414909] [leak_check] [<ffffffffa01e2f1b>] f2fs_mkdir+0xbb/0x150 [f2fs]
> [  231.414914] [leak_check] [<ffffffff811f2a37>] vfs_mkdir+0xb7/0x160
> [  231.414918] [leak_check] [<ffffffff811f367f>] SyS_mkdir+0x5f/0xc0
> [  231.414923] [leak_check] [<ffffffff81680729>] system_call_fastpath+0x16/0x1b
> [  231.414931] [leak_check] [<ffffffffffffffff>] 0xffffffffffffffff
> 
> 
> P.S. It was required to add 'slub_debug' kernel options for make SLUB output correct cache name,
> otherwise cache "f2fs_dirty_dir_entry" was merged into "free_nid" one. It was surprise for me,
> that's why patch investigation took so long time.
>