linux-kernel - Re: [f2fs-dev] [PATCH] f2fs: don't reserve block for empty file when convert inline, page

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Date:   Thu, 5 Jan 2017 00:02:49 +0800
From:   Chao Yu <chao@...nel.org>
To:     Kinglong Mee <kinglongmee@...il.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH] f2fs: don't reserve block for empty file when
 convert inline, page

On 2017/1/4 16:27, Kinglong Mee wrote:
> On 1/4/2017 09:23, Jaegeuk Kim wrote:
>> Hi Kinglong,
>>
>> On 01/02, Kinglong Mee wrote:
>>> A test program gets the SEEK_DATA with two values between
>>> a new created file and the exist file on f2fs filesystem. 
>>>
>>> F2FS filesystem,  (the first "test1" is a new file)
>>> # ./lseektest /f2fs/test1
>>> SEEK_DATA size != 0 (offset = 8192)
>>> # ./lseektest /f2fs/test1
>>> SEEK_DATA size != 0 (offset = 4096)
>>>
>>> PNFS filesystem, (the first "test1" is a new file)
>>> # ./lseektest /pnfs/test1
>>> SEEK_DATA size != 0 (offset = 4096)
>>> # ./lseektest /pnfs/test1
>>> SEEK_DATA size != 0 (offset = 4096)
>>>
>>> # cat lseektest.c
>>>
>>> #include <stdio.h>
>>> #include <string.h>
>>> #include <stdlib.h>
>>> #include <unistd.h>
>>> #include <errno.h>
>>> #include <sys/types.h>
>>> #include <sys/stat.h>
>>> #include <fcntl.h>
>>>
>>> #ifndef SEEK_DATA
>>> #define SEEK_DATA      3
>>> #define SEEK_HOLE      4
>>> #endif
>>>
>>> int main(int argc, char **argv)
>>> {
>>>         char *filename = argv[1];
>>>         int offset = 1, i = 0, fd = -1;
>>>
>>>         if (argc < 2) {
>>>                 printf("Usage: %s f2fsfilename\n", argv[0]);
>>>                 return -1;
>>>         }
>>>
>>>         /*
>>>         if (!access(filename, F_OK) || errno != ENOENT) {
>>>                 printf("Needs a new file for test, %m\n");
>>>                 return -1;
>>>         }*/
>>>
>>>         fd = open(filename, O_RDWR | O_CREAT, 0777);
>>>         if (fd < 0) {
>>>                 printf("Create test file %s failed, %m\n", filename);
>>>                 return -1;
>>>         }
>>>
>>>         for (i = 0; i < 20; i++) {
>>>                 offset = 1 << i;
>>>                 ftruncate(fd, 0);
>>>                 lseek(fd, offset, SEEK_SET);
>>>                 write(fd, "test", 5);
>>>                 /* Get the alloc size by seek data equal zero*/
>>>                 if (lseek(fd, 0, SEEK_DATA)) {
>>>                         printf("SEEK_DATA size != 0 (offset = %d)\n", offset);
>>>                         break;
>>>                 }
>>>         }
>>>
>>>         close(fd);
>>>         return 0;
>>> }
>>>
>>> Signed-off-by: Kinglong Mee <kinglongmee@...il.com>
>>> ---
>>>  fs/f2fs/inline.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
>>> index e32a9e5..6c8d099 100644
>>> --- a/fs/f2fs/inline.c
>>> +++ b/fs/f2fs/inline.c
>>> @@ -117,7 +117,7 @@ int f2fs_convert_inline_page(struct dnode_of_data *dn, struct page *page)
>>>  	};
>>>  	int dirty, err;
>>>  
>>> -	if (!f2fs_exist_data(dn->inode))
>>> +	if (!f2fs_exist_data(dn->inode) || !i_size_read(dn->inode))
>>>  		goto clear_out;
>>
>> The point is that f2fs_exist_data() should return true, since the file was
>> truncated to 0. So, could you check this out?
> 
> Yes, that's right.
> This patch is useful. 
> 
> Tested-by: Kinglong Mee <kinglongmee@...il.com>

Reviewed-by: Chao Yu <yuchao0@...wei.com>

Thanks,

> 
> thanks,
> Kinglong Mee
> 
>>
>> Thanks,
>>
>> ---
>>  fs/f2fs/file.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 826fefc05fb1..ba2021e01c33 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -570,6 +570,8 @@ int truncate_blocks(struct inode *inode, u64 from, bool lock)
>>  	if (f2fs_has_inline_data(inode)) {
>>  		if (truncate_inline_inode(ipage, from))
>>  			set_page_dirty(ipage);
>> +		if (from == 0)
>> +			clear_inode_flag(inode, FI_DATA_EXIST);
>>  		f2fs_put_page(ipage, 1);
>>  		truncate_page = true;
>>  		goto out;
>>
> 
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