Hello:
Can we modify it like this
First:
modify "return (n_free_chunks > 0) ? 1 : 0;"
Second:
In the function "yaffs_file_write"
yaffs_gross_lock(dev);
n_free_chunks = yaffs_get_n_free_chunks(dev);
yaffs_gross_unlock(dev);
if (n_free_chunks > 20 )
n_written = yaffs_wr_file(obj, buf, ipos, n, 0);
else
n_written = yaffs_wr_file(obj, buf, ipos, n, 1);
So we can get through write_end() .The data will not be just
in the cache when multiple processes simultaneously write.
What do you think ?
Thanks you
Regards
chenjie
On 2015/8/4 18:40, chenjie wrote:
> Hello:
> Can we modify it like this
> First:
> modify "return (n_free_chunks > 0) ? 1 : 0;"
>
> Second:
> In the function "yaffs_file_write"
>
> yaffs_gross_lock(dev);
> n_free_chunks = yaffs_get_n_free_chunks(dev);
> yaffs_gross_unlock(dev);
>
> if (n_free_chunks > 20 )
> n_written = yaffs_wr_file(obj, buf, ipos, n, 0);
> else
> n_written = yaffs_wr_file(obj, buf, ipos, n, 1);
>
> So we can get through write_end() .The data will not be just
> in the cache when multiple processes simultaneously write.
>
> What do you think ?
>
> Thanks you
>
> Regards
>
> chenjie
>
>
>
>
>
>
>
> On 2015/8/4 6:50, Charles Manning wrote:
>> I don't think that will work.
>>
>> Consider the case when multiple processes simultaneously write to the
>> file system. If they all get past write_begin(), but have not yet got
>> through write_end() then yaffs has committed to storing the data even
>> if there is no space available.
>>
>> I do however see your point. An overwrite might be refused even though
>> it really does not use any space.
>>
>> I will see if there are any page buffer flags we can use to determine
>> if the page has already been written.
>>
>> That would allow us to do something like:
>>
>> if (page has previously been written)
>> return OK; /* it is an overwrite so it does not consume space */
>> else
>> return n_free_chunks > commit_count; /* Is there space to take more data */
>>
>>
>> On Mon, Aug 3, 2015 at 9:57 PM, chenjie <chenjie6@huawei.com> wrote:
>>>
>>>
>>> Hello
>>> I think this is no need, just "return (n_free_chunks > 0) ? 1 : 0;" is OK.
>>>
>>> if not , we can not overwrite a file with an existent file
>>> when the chunk was less than 20.
>>>
>>> What do you think ?
>>>
>>>
>>> Thanks you
>>>
>>> Regards
>>>
>>> chenjie
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On 2015/7/31 6:13, Charles Manning wrote:
>>>> The purpose of yaffs_hold_space() is to support the write_begin VFS method.
>>>>
>>>> write_begin asks the file system to commit enough space to do the actual write in write_end.
>>>>
>>>> Strictly speaking this should really be handled with counter of committed space that is incremented on every write_begin and decremented on every write_end.
>>>>
>>>> However, it is workable to just not expect there to be more than n writes in progress at a time. n=20 seems rather conservative.
>>>>
>>>> -- Charles
>>>>
>>>>
>>>> On Thu, Jul 30, 2015 at 3:04 PM, chenjie <chenjie6@huawei.com <mailto:chenjie6@huawei.com>> wrote:
>>>>
>>>>
>>>> Hi:
>>>> why the yaffs_hold_space reserved 20 chunk?
>>>> return (n_free_chunks > 20) ? 1 : 0;
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
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