Joseph Qi
2015-Sep-09 09:13 UTC
[Ocfs2-devel] [PATCH] ocfs2: Fill-in the unused portion of the block with zeros by dio_zero_block()
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 ======> nothingI 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 <jiangyiwen at 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 at oss.oracle.com > https://oss.oracle.com/mailman/listinfo/ocfs2-devel > >
Zhen Ren
2015-Sep-09 10:42 UTC
[Ocfs2-devel] [PATCH] ocfs2: Fill-in the unused portion of the block with zeros by dio_zero_block()
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 ;-) Thanks. -- Eric Ren>>> Joseph Qi <joseph.qi at 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 ======> nothingI 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 <jiangyiwen at 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 at oss.oracle.com > https://oss.oracle.com/mailman/listinfo/ocfs2-devel > >