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

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Message-ID: <65c348f6-48ce-e810-72f4-0bf86c39d0b6@gmail.com>
Date:   Mon, 2 Jan 2017 22:56:46 +0800
From:   Kinglong Mee <kinglongmee@...il.com>
To:     jaegeuk@...nel.org, linux-f2fs-devel@...ts.sourceforge.net,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Chao Yu <yuchao0@...wei.com>, kinglongmee@...il.com
Subject: [PATCH] f2fs: don't reserve block for empty file when convert inline,
 page

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;
 
 	err = f2fs_reserve_block(dn, 0);
-- 
2.9.3