| Message ID | 1315984587-5039-1-git-send-email-tm@tao.ma |
|---|---|
| State | Accepted, archived |
| Headers | show |
On 9/14/11 2:16 AM, Tao Ma wrote: > From: Tao Ma <boyu.mt@taobao.com> > > When we want to convert the unitialized extent in direct write, > we can either do it in ext4_end_io_nolock(AIO case) or in > ext4_ext_direct_IO(non AIO case) and EXT4_I(inode)->cur_aio_dio > is a guard for ext4_ext_map_blocks to find the right case. > In e9e3bcecf, we mistakenly change it by: > - if (io) > + if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { > io->flag = EXT4_IO_END_UNWRITTEN; > - else > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } else > ext4_set_inode_state(inode, > EXT4_STATE_DIO_UNWRITTEN); > > So now if we map 2 blocks, and the first one set the EXT_IO_END_UNWRITTEN, the > 2nd mapping will set inode state because of the check for the flag. This is > wrong. Argh, yes, I think you are right. Pesky else clause. :( Do you have a testcase for this? And what is the user-visible outcome of the error, is it data corruption? > Cc: Eric Sandeen <sandeen@redhat.com> > Cc: "Theodore Ts'o" <tytso@mit.edu> > Signed-off-by: Tao Ma <boyu.mt@taobao.com> > --- > fs/ext4/extents.c | 16 ++++++++++------ > 1 files changed, 10 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 57cf568..8db6743 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -3190,9 +3190,11 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, > * that this IO needs to conversion to written when IO is > * completed > */ > - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { > - io->flag = EXT4_IO_END_UNWRITTEN; > - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + if (io) { > + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { > + io->flag = EXT4_IO_END_UNWRITTEN; > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } > } else > ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); > if (ext4_should_dioread_nolock(inode)) > @@ -3572,9 +3574,11 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, > * that we need to perform conversion when IO is done. > */ > if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { > - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { > - io->flag = EXT4_IO_END_UNWRITTEN; > - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + if (io) { > + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { > + io->flag = EXT4_IO_END_UNWRITTEN; > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } > } else > ext4_set_inode_state(inode, > EXT4_STATE_DIO_UNWRITTEN); -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/15/2011 01:06 AM, Eric Sandeen wrote: > On 9/14/11 2:16 AM, Tao Ma wrote: >> From: Tao Ma <boyu.mt@taobao.com> >> >> When we want to convert the unitialized extent in direct write, >> we can either do it in ext4_end_io_nolock(AIO case) or in >> ext4_ext_direct_IO(non AIO case) and EXT4_I(inode)->cur_aio_dio >> is a guard for ext4_ext_map_blocks to find the right case. >> In e9e3bcecf, we mistakenly change it by: >> - if (io) >> + if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { >> io->flag = EXT4_IO_END_UNWRITTEN; >> - else >> + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); >> + } else >> ext4_set_inode_state(inode, >> EXT4_STATE_DIO_UNWRITTEN); >> >> So now if we map 2 blocks, and the first one set the EXT_IO_END_UNWRITTEN, the >> 2nd mapping will set inode state because of the check for the flag. This is >> wrong. > > Argh, yes, I think you are right. Pesky else clause. :( > > Do you have a testcase for this? And what is the user-visible outcome of the error, > is it data corruption? sure, a very simple case can expose this. fallocate -o 0 -l 1048576 $MNT_DIR/b aio_test $MNT_DIR/b 4096 4096 aio_test $MNT_DIR/b 0 12288 The 2nd aio test will set the inode state. Currently, at least from my test, it doesn't cause any data corruption because we only check EXT4_STATE_DIO_UNWRITTEN like this: if (ret > 0 && ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN)) So only if __blockdev_direct_IO returns us ret > 0, we will test this flag. But the inode will have this flag from then on. I am not sure whether there are other places complaining of it. But I think we need this fix, first to make it more readable(at least it is a little bit hard for me to understand the old one ;) ) and second to avoid any future possible bug. Thanks Tao > >> Cc: Eric Sandeen <sandeen@redhat.com> >> Cc: "Theodore Ts'o" <tytso@mit.edu> >> Signed-off-by: Tao Ma <boyu.mt@taobao.com> >> --- >> fs/ext4/extents.c | 16 ++++++++++------ >> 1 files changed, 10 insertions(+), 6 deletions(-) >> >> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >> index 57cf568..8db6743 100644 >> --- a/fs/ext4/extents.c >> +++ b/fs/ext4/extents.c >> @@ -3190,9 +3190,11 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, >> * that this IO needs to conversion to written when IO is >> * completed >> */ >> - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { >> - io->flag = EXT4_IO_END_UNWRITTEN; >> - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); >> + if (io) { >> + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { >> + io->flag = EXT4_IO_END_UNWRITTEN; >> + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); >> + } >> } else >> ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); >> if (ext4_should_dioread_nolock(inode)) >> @@ -3572,9 +3574,11 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, >> * that we need to perform conversion when IO is done. >> */ >> if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { >> - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { >> - io->flag = EXT4_IO_END_UNWRITTEN; >> - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); >> + if (io) { >> + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { >> + io->flag = EXT4_IO_END_UNWRITTEN; >> + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); >> + } >> } else >> ext4_set_inode_state(inode, >> EXT4_STATE_DIO_UNWRITTEN); > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/14/2011 03:16 PM, Tao Ma wrote: > From: Tao Ma <boyu.mt@taobao.com> > > When we want to convert the unitialized extent in direct write, > we can either do it in ext4_end_io_nolock(AIO case) or in > ext4_ext_direct_IO(non AIO case) and EXT4_I(inode)->cur_aio_dio > is a guard for ext4_ext_map_blocks to find the right case. > In e9e3bcecf, we mistakenly change it by: > - if (io) > + if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { > io->flag = EXT4_IO_END_UNWRITTEN; > - else > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } else > ext4_set_inode_state(inode, > EXT4_STATE_DIO_UNWRITTEN); > > So now if we map 2 blocks, and the first one set the EXT_IO_END_UNWRITTEN, the > 2nd mapping will set inode state because of the check for the flag. This is > wrong. > > Cc: Eric Sandeen <sandeen@redhat.com> > Cc: "Theodore Ts'o" <tytso@mit.edu> > Signed-off-by: Tao Ma <boyu.mt@taobao.com> ping? > --- > fs/ext4/extents.c | 16 ++++++++++------ > 1 files changed, 10 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 57cf568..8db6743 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -3190,9 +3190,11 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, > * that this IO needs to conversion to written when IO is > * completed > */ > - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { > - io->flag = EXT4_IO_END_UNWRITTEN; > - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + if (io) { > + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { > + io->flag = EXT4_IO_END_UNWRITTEN; > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } > } else > ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); > if (ext4_should_dioread_nolock(inode)) > @@ -3572,9 +3574,11 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, > * that we need to perform conversion when IO is done. > */ > if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { > - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { > - io->flag = EXT4_IO_END_UNWRITTEN; > - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + if (io) { > + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { > + io->flag = EXT4_IO_END_UNWRITTEN; > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } > } else > ext4_set_inode_state(inode, > EXT4_STATE_DIO_UNWRITTEN); -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Sep 14, 2011 at 03:16:27PM +0800, Tao Ma wrote: > From: Tao Ma <boyu.mt@taobao.com> > > When we want to convert the unitialized extent in direct write, > we can either do it in ext4_end_io_nolock(AIO case) or in > ext4_ext_direct_IO(non AIO case) and EXT4_I(inode)->cur_aio_dio > is a guard for ext4_ext_map_blocks to find the right case. Applied, thanks. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 57cf568..8db6743 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3190,9 +3190,11 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, * that this IO needs to conversion to written when IO is * completed */ - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { - io->flag = EXT4_IO_END_UNWRITTEN; - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); + if (io) { + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { + io->flag = EXT4_IO_END_UNWRITTEN; + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); + } } else ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); if (ext4_should_dioread_nolock(inode)) @@ -3572,9 +3574,11 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, * that we need to perform conversion when IO is done. */ if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { - if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) { - io->flag = EXT4_IO_END_UNWRITTEN; - atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); + if (io) { + if (!(io->flag & EXT4_IO_END_UNWRITTEN)) { + io->flag = EXT4_IO_END_UNWRITTEN; + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); + } } else ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);