| Message ID | 1323235287-29806-1-git-send-email-xiaoqiangnk@gmail.com |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Tue, Dec 6, 2011 at 21:21, Yongqiang Yang <xiaoqiangnk@gmail.com> wrote: > If a file is fallocated on a hole, map->m_lblk + map->m_len may be greater > than ee_block + ee_len. Could you please detail a scenario that leads to this check being invalid? As I'm to blame for the faulty BUG_ON I'd like to use this as an opportunity to get properly edified. > Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> > --- > fs/ext4/extents.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 6f0300e..29bb629 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -2943,7 +2943,6 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, > /* Pre-conditions */ > BUG_ON(!ext4_ext_is_uninitialized(ex)); > BUG_ON(!in_range(map->m_lblk, ee_block, ee_len)); > - BUG_ON(map->m_lblk + map->m_len > ee_block + ee_len); For a bit I thought this would break the fast path logic, however it gets protected by the checks marked /*L1*/ and /*L2*/ since m_lblk == ee_block (L1) and m_len < ee_len (L2). Regards - Eric > > /* > * Attempt to transfer newly initialized blocks from the currently > -- > 1.7.5.1 > > -- > 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 -- 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
[Yet another resend, without HTML and _with_ the list CC'ed. Apologies for the spam] On Fri, Dec 9, 2011 at 19:36, Yongqiang Yang <xiaoqiangnk@gmail.com> wrote: > > > On Saturday, December 10, 2011, Eric Gouriou <egouriou@google.com> wrote: >> On Tue, Dec 6, 2011 at 21:21, Yongqiang Yang <xiaoqiangnk@gmail.com> >> wrote: >>> If a file is fallocated on a hole, map->m_lblk + map->m_len may be >>> greater >>> than ee_block + ee_len. >> >> Could you please detail a scenario that leads to this check being invalid? >> As I'm to blame for the faulty BUG_ON I'd like to use this as an >> opportunity >> to get properly edified. > It's easy to reproduce, I think. Just need to write beyond fallocated > blocks, write back would submit a request to ext4_map_blocks with blocks > part of which are fallocated while other part of which are not, then the > bug-on would happen. Thanks, this makes sense. > > I met the bug_on during fsx and after the patch applied it works normal. > > I think Allison also tested with this patch. > > Yongqiang.. > >> >>> Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Reviewed-by: Eric Gouriou <egouriou@google.com> Thanks - Eric >>> --- >>> fs/ext4/extents.c | 1 - >>> 1 files changed, 0 insertions(+), 1 deletions(-) >>> >>> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >>> index 6f0300e..29bb629 100644 >>> --- a/fs/ext4/extents.c >>> +++ b/fs/ext4/extents.c >>> @@ -2943,7 +2943,6 @@ static int ext4_ext_convert_to_initialized(handle_t >>> *handle, >>> /* Pre-conditions */ >>> BUG_ON(!ext4_ext_is_uninitialized(ex)); >>> BUG_ON(!in_range(map->m_lblk, ee_block, ee_len)); >>> - BUG_ON(map->m_lblk + map->m_len > ee_block + ee_len); >> >> For a bit I thought this would break the fast path logic, however it gets >> protected by the checks marked /*L1*/ and /*L2*/ since m_lblk == ee_block >> (L1) and m_len < ee_len (L2). >> >> Regards - Eric >> >>> >>> /* >>> * Attempt to transfer newly initialized blocks from the currently >>> -- >>> 1.7.5.1 >>> >>> -- >>> 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 >> > > -- > Best Wishes > Yongqiang Yang > -- 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, Dec 07, 2011 at 01:21:26PM +0800, Yongqiang Yang wrote: > If a file is fallocated on a hole, map->m_lblk + map->m_len may be greater > than ee_block + ee_len. > > Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Thanks, applied. - 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 6f0300e..29bb629 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2943,7 +2943,6 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, /* Pre-conditions */ BUG_ON(!ext4_ext_is_uninitialized(ex)); BUG_ON(!in_range(map->m_lblk, ee_block, ee_len)); - BUG_ON(map->m_lblk + map->m_len > ee_block + ee_len); /* * Attempt to transfer newly initialized blocks from the currently
If a file is fallocated on a hole, map->m_lblk + map->m_len may be greater than ee_block + ee_len. Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> --- fs/ext4/extents.c | 1 - 1 files changed, 0 insertions(+), 1 deletions(-)