Re: UBIFS assert failed in ubifs_dirty_inode

Jeff Angielski
2010-01-27T01:44:32Z

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Artem Bityutskiy wrote:
> On Mon, 2010-01-25 at 23:48 -0600, Matt Mackall wrote:
>> Hmm. I'd just as soon drop it entirely. Here's a patch. Herbert, you
>> want to send this through your crypto tree?
>>
>>
>> random: drop weird m_time/a_time manipulation
>>
>> No other driver does anything remotely like this that I know of except
>> for the tty drivers, and I can't see any reason for random/urandom to do
>> it. In fact, it's a (trivial, harmless) timing information leak. And
>> obviously, it generates power- and flash-cycle wasting I/O, especially
>> if combined with something like hwrngd. Also, it breaks ubifs's
>> expectations.
>>
>> Signed-off-by: Matt Mackall <mpm@selenic.com>
>>
>> diff -r 29db0c391ce8 drivers/char/random.c
>> --- a/drivers/char/random.c Sun Jan 17 11:01:16 2010 -0800
>> +++ b/drivers/char/random.c Mon Jan 25 23:32:00 2010 -0600
>> @@ -1051,12 +1051,6 @@
>> /* like a named pipe */
>> }
>>
>> - /*
>> - * If we gave the user some bytes, update the access time.
>> - */
>> - if (count)
>> - file_accessed(file);
>> -
>> return (count ? count : retval);
>> }
>>
>> @@ -1116,8 +1110,6 @@
>> if (ret)
>> return ret;
>>
>> - inode->i_mtime = current_fs_time(inode->i_sb);
>> - mark_inode_dirty(inode);
>> return (ssize_t)count;
>> }
>
> It may brake other FSes expectations, theoretically, as well.
>
> Anyway, I'm perfectly fine if this is removed.
>
> Jeff, could you please try Matt's patch and report back if you still
> have issues or not. If no, you can use this as a temporary work-around
> until a proper fix hits upstream or ubifs-2.6.git.

Matt's patch did not compile as written. I tried to implement what I
think he was trying to do and created this patch (it seems to match the
guts of what inode_setattr() was looking for):

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 8258982..70f16c7 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1108,6 +1108,7 @@ static ssize_t random_write(struct file *file,
const char __user *buffer,
{
size_t ret;
struct inode *inode = file->f_path.dentry->d_inode;
+ struct iattr attr;

ret = write_pool(&blocking_pool, buffer, count);
if (ret)
@@ -1116,8 +1117,12 @@ static ssize_t random_write(struct file *file,
const char __user *buffer,
if (ret)
return ret;

- inode->i_mtime = current_fs_time(inode->i_sb);
- mark_inode_dirty(inode);
+ attr.ia_mtime = current_fs_time(inode->i_sb);
+ attr.ia_valid = ATTR_MTIME;
+ ret = inode_setattr(inode, &attr);
+ if (ret)
+ return ret;
+
return (ssize_t)count;
}

However, this patch does not fix the problem. I still see the same
errors. Matt, is this what you were trying to do?

I've also included the console dump just in case.

I did try Artem's patch that removes the offending code and that works
fine. No problems on any reboots or reading/writing the UBIFS.

--
Jeff Angielski
The PTR Group
www.theptrgroup.com

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