diff mbox series

[f2fs-dev,v4] f2fs: add check for deleted inode

Message ID 20250212072742.977248-1-chao@kernel.org (mailing list archive)
State New
Headers show
Series [f2fs-dev,v4] f2fs: add check for deleted inode | expand

Commit Message

Chao Yu Feb. 12, 2025, 7:27 a.m. UTC 
From: Leo Stone <leocstone@gmail.com>

The syzbot reproducer mounts a f2fs image, then tries to unlink an
existing file. However, the unlinked file already has a link count of 0
when it is read for the first time in do_read_inode().

Add a check to sanity_check_inode() for i_nlink == 0.

[Chao Yu: rebase the code and fix orphan inode recovery issue]
Reported-by: syzbot+b01a36acd7007e273a83@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b01a36acd7007e273a83
Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure")
Signed-off-by: Leo Stone <leocstone@gmail.com>
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/checkpoint.c | 4 ++++
 fs/f2fs/f2fs.h       | 1 +
 fs/f2fs/inode.c      | 6 ++++++
 3 files changed, 11 insertions(+)

Comments

Jaegeuk Kim Feb. 12, 2025, 4:47 p.m. UTC | #1 
On 02/12, Chao Yu wrote:
> From: Leo Stone <leocstone@gmail.com>
> 
> The syzbot reproducer mounts a f2fs image, then tries to unlink an
> existing file. However, the unlinked file already has a link count of 0
> when it is read for the first time in do_read_inode().
> 
> Add a check to sanity_check_inode() for i_nlink == 0.
> 
> [Chao Yu: rebase the code and fix orphan inode recovery issue]
> Reported-by: syzbot+b01a36acd7007e273a83@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=b01a36acd7007e273a83
> Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure")
> Signed-off-by: Leo Stone <leocstone@gmail.com>
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
>  fs/f2fs/checkpoint.c | 4 ++++
>  fs/f2fs/f2fs.h       | 1 +
>  fs/f2fs/inode.c      | 6 ++++++
>  3 files changed, 11 insertions(+)
> 
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index bd890738b94d..ada2c548645c 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -751,6 +751,8 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
>  	if (is_sbi_flag_set(sbi, SBI_IS_WRITABLE))
>  		f2fs_info(sbi, "orphan cleanup on readonly fs");
>  
> +	set_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);

What about using SBI_POR_DOING?

> +
>  	start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);
>  	orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);
>  
> @@ -778,9 +780,11 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
>  		}
>  		f2fs_put_page(page, 1);
>  	}
> +
>  	/* clear Orphan Flag */
>  	clear_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG);
>  out:
> +	clear_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
>  	set_sbi_flag(sbi, SBI_IS_RECOVERED);
>  
>  	return err;
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 05879c6dc4d6..1c75081c0c14 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1322,6 +1322,7 @@ enum {
>  	SBI_IS_CLOSE,				/* specify unmounting */
>  	SBI_NEED_FSCK,				/* need fsck.f2fs to fix */
>  	SBI_POR_DOING,				/* recovery is doing or not */
> +	SBI_ORPHAN_RECOVERY,			/* orphan inodes recovery is doing */
>  	SBI_NEED_SB_WRITE,			/* need to recover superblock */
>  	SBI_NEED_CP,				/* need to checkpoint */
>  	SBI_IS_SHUTDOWN,			/* shutdown by ioctl */
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index d6ad7810df69..02f1b69d03d8 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -386,6 +386,12 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page)
>  		}
>  	}
>  
> +	if (inode->i_nlink == 0 && !is_sbi_flag_set(sbi, SBI_ORPHAN_RECOVERY)) {
> +		f2fs_warn(sbi, "%s: inode (ino=%lx) has a link count of 0",
> +			  __func__, inode->i_ino);
> +		return false;
> +	}
> +
>  	return true;
>  }
>  
> -- 
> 2.48.1.502.g6dc24dfdaf-goog
Chao Yu Feb. 13, 2025, 2 a.m. UTC | #2 
On 2/13/25 00:47, Jaegeuk Kim wrote:
> On 02/12, Chao Yu wrote:
>> From: Leo Stone <leocstone@gmail.com>
>>
>> The syzbot reproducer mounts a f2fs image, then tries to unlink an
>> existing file. However, the unlinked file already has a link count of 0
>> when it is read for the first time in do_read_inode().
>>
>> Add a check to sanity_check_inode() for i_nlink == 0.
>>
>> [Chao Yu: rebase the code and fix orphan inode recovery issue]
>> Reported-by: syzbot+b01a36acd7007e273a83@syzkaller.appspotmail.com
>> Closes: https://syzkaller.appspot.com/bug?extid=b01a36acd7007e273a83
>> Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure")
>> Signed-off-by: Leo Stone <leocstone@gmail.com>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>>  fs/f2fs/checkpoint.c | 4 ++++
>>  fs/f2fs/f2fs.h       | 1 +
>>  fs/f2fs/inode.c      | 6 ++++++
>>  3 files changed, 11 insertions(+)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index bd890738b94d..ada2c548645c 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -751,6 +751,8 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
>>  	if (is_sbi_flag_set(sbi, SBI_IS_WRITABLE))
>>  		f2fs_info(sbi, "orphan cleanup on readonly fs");
>>  
>> +	set_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
> 
> What about using SBI_POR_DOING?

SBI_POR_DOING will cover most flow of f2fs_fill_super(), I think we can add a
separated flag just covering f2fs_recover_orphan_inodes(), so that we can allow
iget() of root_inode and all inodes during roll-forward recovery to do sanity
check nlink w/ zero. What do you think?

Thanks,

> 
>> +
>>  	start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);
>>  	orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);
>>  
>> @@ -778,9 +780,11 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
>>  		}
>>  		f2fs_put_page(page, 1);
>>  	}
>> +
>>  	/* clear Orphan Flag */
>>  	clear_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG);
>>  out:
>> +	clear_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
>>  	set_sbi_flag(sbi, SBI_IS_RECOVERED);
>>  
>>  	return err;
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 05879c6dc4d6..1c75081c0c14 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1322,6 +1322,7 @@ enum {
>>  	SBI_IS_CLOSE,				/* specify unmounting */
>>  	SBI_NEED_FSCK,				/* need fsck.f2fs to fix */
>>  	SBI_POR_DOING,				/* recovery is doing or not */
>> +	SBI_ORPHAN_RECOVERY,			/* orphan inodes recovery is doing */
>>  	SBI_NEED_SB_WRITE,			/* need to recover superblock */
>>  	SBI_NEED_CP,				/* need to checkpoint */
>>  	SBI_IS_SHUTDOWN,			/* shutdown by ioctl */
>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>> index d6ad7810df69..02f1b69d03d8 100644
>> --- a/fs/f2fs/inode.c
>> +++ b/fs/f2fs/inode.c
>> @@ -386,6 +386,12 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page)
>>  		}
>>  	}
>>  
>> +	if (inode->i_nlink == 0 && !is_sbi_flag_set(sbi, SBI_ORPHAN_RECOVERY)) {
>> +		f2fs_warn(sbi, "%s: inode (ino=%lx) has a link count of 0",
>> +			  __func__, inode->i_ino);
>> +		return false;
>> +	}
>> +
>>  	return true;
>>  }
>>  
>> -- 
>> 2.48.1.502.g6dc24dfdaf-goog
Jaegeuk Kim Feb. 13, 2025, 5:38 p.m. UTC | #3 
On 02/13, Chao Yu wrote:
> On 2/13/25 00:47, Jaegeuk Kim wrote:
> > On 02/12, Chao Yu wrote:
> >> From: Leo Stone <leocstone@gmail.com>
> >>
> >> The syzbot reproducer mounts a f2fs image, then tries to unlink an
> >> existing file. However, the unlinked file already has a link count of 0
> >> when it is read for the first time in do_read_inode().
> >>
> >> Add a check to sanity_check_inode() for i_nlink == 0.
> >>
> >> [Chao Yu: rebase the code and fix orphan inode recovery issue]
> >> Reported-by: syzbot+b01a36acd7007e273a83@syzkaller.appspotmail.com
> >> Closes: https://syzkaller.appspot.com/bug?extid=b01a36acd7007e273a83
> >> Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure")
> >> Signed-off-by: Leo Stone <leocstone@gmail.com>
> >> Signed-off-by: Chao Yu <chao@kernel.org>
> >> ---
> >>  fs/f2fs/checkpoint.c | 4 ++++
> >>  fs/f2fs/f2fs.h       | 1 +
> >>  fs/f2fs/inode.c      | 6 ++++++
> >>  3 files changed, 11 insertions(+)
> >>
> >> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> >> index bd890738b94d..ada2c548645c 100644
> >> --- a/fs/f2fs/checkpoint.c
> >> +++ b/fs/f2fs/checkpoint.c
> >> @@ -751,6 +751,8 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
> >>  	if (is_sbi_flag_set(sbi, SBI_IS_WRITABLE))
> >>  		f2fs_info(sbi, "orphan cleanup on readonly fs");
> >>  
> >> +	set_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
> > 
> > What about using SBI_POR_DOING?
> 
> SBI_POR_DOING will cover most flow of f2fs_fill_super(), I think we can add a
> separated flag just covering f2fs_recover_orphan_inodes(), so that we can allow
> iget() of root_inode and all inodes during roll-forward recovery to do sanity
> check nlink w/ zero. What do you think?

Can we do this sanity check after f2fs_iget in the f2fs_unlink() only?

> 
> Thanks,
> 
> > 
> >> +
> >>  	start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);
> >>  	orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);
> >>  
> >> @@ -778,9 +780,11 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
> >>  		}
> >>  		f2fs_put_page(page, 1);
> >>  	}
> >> +
> >>  	/* clear Orphan Flag */
> >>  	clear_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG);
> >>  out:
> >> +	clear_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
> >>  	set_sbi_flag(sbi, SBI_IS_RECOVERED);
> >>  
> >>  	return err;
> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >> index 05879c6dc4d6..1c75081c0c14 100644
> >> --- a/fs/f2fs/f2fs.h
> >> +++ b/fs/f2fs/f2fs.h
> >> @@ -1322,6 +1322,7 @@ enum {
> >>  	SBI_IS_CLOSE,				/* specify unmounting */
> >>  	SBI_NEED_FSCK,				/* need fsck.f2fs to fix */
> >>  	SBI_POR_DOING,				/* recovery is doing or not */
> >> +	SBI_ORPHAN_RECOVERY,			/* orphan inodes recovery is doing */
> >>  	SBI_NEED_SB_WRITE,			/* need to recover superblock */
> >>  	SBI_NEED_CP,				/* need to checkpoint */
> >>  	SBI_IS_SHUTDOWN,			/* shutdown by ioctl */
> >> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> >> index d6ad7810df69..02f1b69d03d8 100644
> >> --- a/fs/f2fs/inode.c
> >> +++ b/fs/f2fs/inode.c
> >> @@ -386,6 +386,12 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page)
> >>  		}
> >>  	}
> >>  
> >> +	if (inode->i_nlink == 0 && !is_sbi_flag_set(sbi, SBI_ORPHAN_RECOVERY)) {
> >> +		f2fs_warn(sbi, "%s: inode (ino=%lx) has a link count of 0",
> >> +			  __func__, inode->i_ino);
> >> +		return false;
> >> +	}
> >> +
> >>  	return true;
> >>  }
> >>  
> >> -- 
> >> 2.48.1.502.g6dc24dfdaf-goog
Chao Yu Feb. 14, 2025, 1:44 a.m. UTC | #4 
On 2/14/25 01:38, Jaegeuk Kim wrote:
> On 02/13, Chao Yu wrote:
>> On 2/13/25 00:47, Jaegeuk Kim wrote:
>>> On 02/12, Chao Yu wrote:
>>>> From: Leo Stone <leocstone@gmail.com>
>>>>
>>>> The syzbot reproducer mounts a f2fs image, then tries to unlink an
>>>> existing file. However, the unlinked file already has a link count of 0
>>>> when it is read for the first time in do_read_inode().
>>>>
>>>> Add a check to sanity_check_inode() for i_nlink == 0.
>>>>
>>>> [Chao Yu: rebase the code and fix orphan inode recovery issue]
>>>> Reported-by: syzbot+b01a36acd7007e273a83@syzkaller.appspotmail.com
>>>> Closes: https://syzkaller.appspot.com/bug?extid=b01a36acd7007e273a83
>>>> Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure")
>>>> Signed-off-by: Leo Stone <leocstone@gmail.com>
>>>> Signed-off-by: Chao Yu <chao@kernel.org>
>>>> ---
>>>>  fs/f2fs/checkpoint.c | 4 ++++
>>>>  fs/f2fs/f2fs.h       | 1 +
>>>>  fs/f2fs/inode.c      | 6 ++++++
>>>>  3 files changed, 11 insertions(+)
>>>>
>>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>>> index bd890738b94d..ada2c548645c 100644
>>>> --- a/fs/f2fs/checkpoint.c
>>>> +++ b/fs/f2fs/checkpoint.c
>>>> @@ -751,6 +751,8 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
>>>>  	if (is_sbi_flag_set(sbi, SBI_IS_WRITABLE))
>>>>  		f2fs_info(sbi, "orphan cleanup on readonly fs");
>>>>  
>>>> +	set_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
>>>
>>> What about using SBI_POR_DOING?
>>
>> SBI_POR_DOING will cover most flow of f2fs_fill_super(), I think we can add a
>> separated flag just covering f2fs_recover_orphan_inodes(), so that we can allow
>> iget() of root_inode and all inodes during roll-forward recovery to do sanity
>> check nlink w/ zero. What do you think?
> 
> Can we do this sanity check after f2fs_iget in the f2fs_unlink() only?

Sure, we need to cover f2fs_rename() as well, please check this:

https://lore.kernel.org/all/67450f9a.050a0220.21d33d.0003.GAE@google.com

Thanks,

> 
>>
>> Thanks,
>>
>>>
>>>> +
>>>>  	start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);
>>>>  	orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);
>>>>  
>>>> @@ -778,9 +780,11 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
>>>>  		}
>>>>  		f2fs_put_page(page, 1);
>>>>  	}
>>>> +
>>>>  	/* clear Orphan Flag */
>>>>  	clear_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG);
>>>>  out:
>>>> +	clear_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
>>>>  	set_sbi_flag(sbi, SBI_IS_RECOVERED);
>>>>  
>>>>  	return err;
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 05879c6dc4d6..1c75081c0c14 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -1322,6 +1322,7 @@ enum {
>>>>  	SBI_IS_CLOSE,				/* specify unmounting */
>>>>  	SBI_NEED_FSCK,				/* need fsck.f2fs to fix */
>>>>  	SBI_POR_DOING,				/* recovery is doing or not */
>>>> +	SBI_ORPHAN_RECOVERY,			/* orphan inodes recovery is doing */
>>>>  	SBI_NEED_SB_WRITE,			/* need to recover superblock */
>>>>  	SBI_NEED_CP,				/* need to checkpoint */
>>>>  	SBI_IS_SHUTDOWN,			/* shutdown by ioctl */
>>>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>>>> index d6ad7810df69..02f1b69d03d8 100644
>>>> --- a/fs/f2fs/inode.c
>>>> +++ b/fs/f2fs/inode.c
>>>> @@ -386,6 +386,12 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page)
>>>>  		}
>>>>  	}
>>>>  
>>>> +	if (inode->i_nlink == 0 && !is_sbi_flag_set(sbi, SBI_ORPHAN_RECOVERY)) {
>>>> +		f2fs_warn(sbi, "%s: inode (ino=%lx) has a link count of 0",
>>>> +			  __func__, inode->i_ino);
>>>> +		return false;
>>>> +	}
>>>> +
>>>>  	return true;
>>>>  }
>>>>  
>>>> -- 
>>>> 2.48.1.502.g6dc24dfdaf-goog
diff mbox series

Patch

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index bd890738b94d..ada2c548645c 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -751,6 +751,8 @@  int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
 	if (is_sbi_flag_set(sbi, SBI_IS_WRITABLE))
 		f2fs_info(sbi, "orphan cleanup on readonly fs");
 
+	set_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
+
 	start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);
 	orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);
 
@@ -778,9 +780,11 @@  int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
 		}
 		f2fs_put_page(page, 1);
 	}
+
 	/* clear Orphan Flag */
 	clear_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG);
 out:
+	clear_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
 	set_sbi_flag(sbi, SBI_IS_RECOVERED);
 
 	return err;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 05879c6dc4d6..1c75081c0c14 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1322,6 +1322,7 @@  enum {
 	SBI_IS_CLOSE,				/* specify unmounting */
 	SBI_NEED_FSCK,				/* need fsck.f2fs to fix */
 	SBI_POR_DOING,				/* recovery is doing or not */
+	SBI_ORPHAN_RECOVERY,			/* orphan inodes recovery is doing */
 	SBI_NEED_SB_WRITE,			/* need to recover superblock */
 	SBI_NEED_CP,				/* need to checkpoint */
 	SBI_IS_SHUTDOWN,			/* shutdown by ioctl */
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index d6ad7810df69..02f1b69d03d8 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -386,6 +386,12 @@  static bool sanity_check_inode(struct inode *inode, struct page *node_page)
 		}
 	}
 
+	if (inode->i_nlink == 0 && !is_sbi_flag_set(sbi, SBI_ORPHAN_RECOVERY)) {
+		f2fs_warn(sbi, "%s: inode (ino=%lx) has a link count of 0",
+			  __func__, inode->i_ino);
+		return false;
+	}
+
 	return true;
 }