On 2015/9/9 18:42, Zhen Ren wrote: > Hi Joseph and Yiwen, > > Sorry for that misoperation. > > This time, I did the same cmds using "hexdump" on ocfs2 and btrfs. > The testing results look the same: > == > laptop:/mnt/shared # dd if=/dev/zero of=hello bs=512 count=1 oflag=direct > ===> on ocfs2 > 1+0 records in > 1+0 records out > 512 bytes (512 B) copied, 0.000834866 s, 613 kB/s > laptop:/mnt/shared # hexdump hello -C > 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > * > 00000200 > laptop:/mnt/shared # truncate hello -s 2097152 > laptop:/mnt/shared # truncate hello -s 2097152 > laptop:/mnt/shared # hexdump hello -C > 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > * > 00200000 > > laptop:~ # dd if=/dev/zero of=hello bs=512 count=1 oflag=direct > ===> on btrfs > 1+0 records in > 1+0 records out > 512 bytes (512 B) copied, 0.000201759 s, 2.5 MB/s > laptop:~ # hexdump hello -C > 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > * > 00000200 > laptop:~ # truncate hello -s 2097152 > laptop:~ # hexdump hello -C > 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > * > 00200000 > == > > BTW, Yiwen, I'm confused by your comment and commit message. > 1. >> file 'hello' should be all zero. But 512~4096 is some random data. > 2. it means in file area 512~4096 is zero not random data. > > Anyway, I didn't look into this case, but just try to understand it. > So, if there's any problem, let it go ;-) sorry, my description is wrong, 512~4096 is zero.
Thanks, Yiwen Jiang > > Thanks. > -- > Eric Ren > >>>> Joseph Qi <joseph...@huawei.com> 09/09/15 6:04 PM >>> > Hi Zhen, > > On 2015/9/9 13:16, Zhen Ren wrote: >> Hi Yiwen, >> >> I try to reproduce this case, but it didn't act like you describe. >> What I did: >> === >> laptop:/mnt/shared # mount | grep ocfs2 >> ocfs2_dlmfs on /dlm type ocfs2_dlmfs (rw,relatime) >> /dev/sda3 on /mnt/shared type ocfs2 >> (rw,relatime,_netdev,heartbeat=local,nointr,data=ordered,errors=remount-ro,atime_quantum=60,coherency=full,user_xattr,acl) >> laptop:/mnt/shared # dd if=/dev/zero of=/mnt/shared/hello bs=512 count=1 >> oflag=direct >> 1+0 records in >> 1+0 records out >> 512 bytes (512 B) copied, 0.000684382 s, 748 kB/s >> laptop:/mnt/shared # truncate hello -s 2097152 >> laptop:/mnt/shared # cat hello ======> nothing > I don't think 'cat' works here. > Could you please use hexdump? > >> laptop:/mnt/shared # uname -r >> 3.16.7-21-desktop >> === >> >> Did I do something wrong? If I misunderstand, please correct me. >> Thanks. >> >> >>> >>> A simplified test case is (this case from Ryan): >>> 1) dd if=/dev/zero of=/mnt/hello bs=512 count=1 oflag=direct; >>> 2) truncate /mnt/hello -s 2097152 >>> file 'hello' is not exist before test. After this command, >>> file 'hello' should be all zero. But 512~4096 is some random data. >>> >>> Setting bh state to new when get a new block, if so, >>> direct_io_worker()->dio_zero_block() will fill-in the unused portion >>> of the block with zero. >>> >>> Signed-off-by: Yiwen Jiang <jiangyi...@huawei.com> >>> --- >>> fs/ocfs2/aops.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c >>> index 1a35c61..bd106b9 100644 >>> --- a/fs/ocfs2/aops.c >>> +++ b/fs/ocfs2/aops.c >>> @@ -581,6 +581,7 @@ static int ocfs2_direct_IO_get_blocks(struct inode >>> *inode, sector_t iblock, >>> ret = -EIO; >>> goto bail; >>> } >>> + set_buffer_new(bh_result); >>> } >>> >>> /* >> >> >> >> >> -- >> Eric, Ren >> >> >> >> >> _______________________________________________ >> Ocfs2-devel mailing list >> Ocfs2-devel@oss.oracle.com >> https://oss.oracle.com/mailman/listinfo/ocfs2-devel >> >> > > > > > > . > _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel
