| Message ID | 1359643738-22435-1-git-send-email-dmonakhov@openvz.org |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Thu 31-01-13 18:48:58, Dmitry Monakhov wrote: > When ext4_split_extent_at() ends up doing zeroout & conversion to > initialized instead of split & conversion, ext4_split_extent() gets > confused and can wrongly mark the extent back as uninitialized resulting in > end IO code getting confused from large unwritten extents and may result in > data loss. > > The example of problematic behavior is: > lblk len lblk len > ext4_split_extent() (ex=[1000,30,uninit], map=[1010,10]) > ext4_split_extent_at() (split [1000,30,uninit] at 1020) > ext4_ext_insert_extent() -> ENOSPC > ext4_ext_zeroout() > -> extent [1000,30] is now initialized > ext4_split_extent_at() (split [1000,30,init] at 1010, > MARK_UNINIT1 | MARK_UNINIT2) > -> extent is split and parts marked as uninitialized > > Fix the problem by rechecking extent type after the first > ext4_split_extent_at() returns. None of split_flags can not be applied to > initialized extent so this patch also add BUG_ON to prevent similar issues > in future. > > TESTCASE: https://github.com/dmonakhov/xfstests/commit/1a1c4f337d4d198803436c63a56625b1a78d8a5e > > Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Looks good. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/ext4/extents.c | 22 ++++++++++++++++------ > 1 files changed, 16 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index fd51469..05222d5 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -2982,6 +2982,10 @@ static int ext4_split_extent_at(handle_t *handle, > newblock = split - ee_block + ext4_ext_pblock(ex); > > BUG_ON(split < ee_block || split >= (ee_block + ee_len)); > + BUG_ON(!ext4_ext_is_uninitialized(ex) && > + split_flag & (EXT4_EXT_MAY_ZEROOUT | > + EXT4_EXT_MARK_UNINIT1 | > + EXT4_EXT_MARK_UNINIT2)); > > err = ext4_ext_get_access(handle, inode, path + depth); > if (err) > @@ -3091,18 +3095,24 @@ static int ext4_split_extent(handle_t *handle, > if (err) > goto out; > } > - > + /* > + * Update path is required because previous ext4_split_extent_at() may > + * result in split of original leaf or extent zeroout. > + */ > ext4_ext_drop_refs(path); > path = ext4_ext_find_extent(inode, map->m_lblk, path); > if (IS_ERR(path)) > return PTR_ERR(path); > + depth = ext_depth(inode); > + ex = path[depth].p_ext; > + uninitialized = ext4_ext_is_uninitialized(ex); > + split_flag1 = 0; > > if (map->m_lblk >= ee_block) { > - split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT; > - if (uninitialized) > - split_flag1 |= EXT4_EXT_MARK_UNINIT1; > - if (split_flag & EXT4_EXT_MARK_UNINIT2) > - split_flag1 |= EXT4_EXT_MARK_UNINIT2; > + if (uninitialized) { > + split_flag1 = EXT4_EXT_MARK_UNINIT1; > + split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT | EXT4_EXT_MARK_UNINIT2); > + } > err = ext4_split_extent_at(handle, inode, path, > map->m_lblk, split_flag1, flags); > if (err) > -- > 1.7.1 > > -- > 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
On 1/31/13 8:48 AM, Dmitry Monakhov wrote: > When ext4_split_extent_at() ends up doing zeroout & conversion to > initialized instead of split & conversion, ext4_split_extent() gets > confused and can wrongly mark the extent back as uninitialized resulting in > end IO code getting confused from large unwritten extents and may result in > data loss. > > The example of problematic behavior is: > lblk len lblk len > ext4_split_extent() (ex=[1000,30,uninit], map=[1010,10]) > ext4_split_extent_at() (split [1000,30,uninit] at 1020) > ext4_ext_insert_extent() -> ENOSPC > ext4_ext_zeroout() > -> extent [1000,30] is now initialized > ext4_split_extent_at() (split [1000,30,init] at 1010, > MARK_UNINIT1 | MARK_UNINIT2) > -> extent is split and parts marked as uninitialized > > Fix the problem by rechecking extent type after the first > ext4_split_extent_at() returns. None of split_flags can not be applied to > initialized extent so this patch also add BUG_ON to prevent similar issues > in future. > > TESTCASE: https://github.com/dmonakhov/xfstests/commit/1a1c4f337d4d198803436c63a56625b1a78d8a5e Dmitry, thanks - want to send that testcase (and any others you've collected that aren't in the sgi repo) to xfs@oss.sgi.com? Thanks, -Eric > Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> > --- > fs/ext4/extents.c | 22 ++++++++++++++++------ > 1 files changed, 16 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index fd51469..05222d5 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -2982,6 +2982,10 @@ static int ext4_split_extent_at(handle_t *handle, > newblock = split - ee_block + ext4_ext_pblock(ex); > > BUG_ON(split < ee_block || split >= (ee_block + ee_len)); > + BUG_ON(!ext4_ext_is_uninitialized(ex) && > + split_flag & (EXT4_EXT_MAY_ZEROOUT | > + EXT4_EXT_MARK_UNINIT1 | > + EXT4_EXT_MARK_UNINIT2)); > > err = ext4_ext_get_access(handle, inode, path + depth); > if (err) > @@ -3091,18 +3095,24 @@ static int ext4_split_extent(handle_t *handle, > if (err) > goto out; > } > - > + /* > + * Update path is required because previous ext4_split_extent_at() may > + * result in split of original leaf or extent zeroout. > + */ > ext4_ext_drop_refs(path); > path = ext4_ext_find_extent(inode, map->m_lblk, path); > if (IS_ERR(path)) > return PTR_ERR(path); > + depth = ext_depth(inode); > + ex = path[depth].p_ext; > + uninitialized = ext4_ext_is_uninitialized(ex); > + split_flag1 = 0; > > if (map->m_lblk >= ee_block) { > - split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT; > - if (uninitialized) > - split_flag1 |= EXT4_EXT_MARK_UNINIT1; > - if (split_flag & EXT4_EXT_MARK_UNINIT2) > - split_flag1 |= EXT4_EXT_MARK_UNINIT2; > + if (uninitialized) { > + split_flag1 = EXT4_EXT_MARK_UNINIT1; > + split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT | EXT4_EXT_MARK_UNINIT2); > + } > err = ext4_split_extent_at(handle, inode, path, > map->m_lblk, split_flag1, flags); > if (err) > -- 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 Fri, 01 Feb 2013 10:09:34 -0600, Eric Sandeen <sandeen@redhat.com> wrote: > On 1/31/13 8:48 AM, Dmitry Monakhov wrote: > > When ext4_split_extent_at() ends up doing zeroout & conversion to > > initialized instead of split & conversion, ext4_split_extent() gets > > confused and can wrongly mark the extent back as uninitialized resulting in > > end IO code getting confused from large unwritten extents and may result in > > data loss. > > > > The example of problematic behavior is: > > lblk len lblk len > > ext4_split_extent() (ex=[1000,30,uninit], map=[1010,10]) > > ext4_split_extent_at() (split [1000,30,uninit] at 1020) > > ext4_ext_insert_extent() -> ENOSPC > > ext4_ext_zeroout() > > -> extent [1000,30] is now initialized > > ext4_split_extent_at() (split [1000,30,init] at 1010, > > MARK_UNINIT1 | MARK_UNINIT2) > > -> extent is split and parts marked as uninitialized > > > > Fix the problem by rechecking extent type after the first > > ext4_split_extent_at() returns. None of split_flags can not be applied to > > initialized extent so this patch also add BUG_ON to prevent similar issues > > in future. > > > > TESTCASE: https://github.com/dmonakhov/xfstests/commit/1a1c4f337d4d198803436c63a56625b1a78d8a5e > > Dmitry, thanks - want to send that testcase (and any others you've collected > that aren't in the sgi repo) to xfs@oss.sgi.com? Off course. I'll a bunch of my tests this week. > > Thanks, > -Eric > > > Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> > > --- > > fs/ext4/extents.c | 22 ++++++++++++++++------ > > 1 files changed, 16 insertions(+), 6 deletions(-) > > > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > > index fd51469..05222d5 100644 > > --- a/fs/ext4/extents.c > > +++ b/fs/ext4/extents.c > > @@ -2982,6 +2982,10 @@ static int ext4_split_extent_at(handle_t *handle, > > newblock = split - ee_block + ext4_ext_pblock(ex); > > > > BUG_ON(split < ee_block || split >= (ee_block + ee_len)); > > + BUG_ON(!ext4_ext_is_uninitialized(ex) && > > + split_flag & (EXT4_EXT_MAY_ZEROOUT | > > + EXT4_EXT_MARK_UNINIT1 | > > + EXT4_EXT_MARK_UNINIT2)); > > > > err = ext4_ext_get_access(handle, inode, path + depth); > > if (err) > > @@ -3091,18 +3095,24 @@ static int ext4_split_extent(handle_t *handle, > > if (err) > > goto out; > > } > > - > > + /* > > + * Update path is required because previous ext4_split_extent_at() may > > + * result in split of original leaf or extent zeroout. > > + */ > > ext4_ext_drop_refs(path); > > path = ext4_ext_find_extent(inode, map->m_lblk, path); > > if (IS_ERR(path)) > > return PTR_ERR(path); > > + depth = ext_depth(inode); > > + ex = path[depth].p_ext; > > + uninitialized = ext4_ext_is_uninitialized(ex); > > + split_flag1 = 0; > > > > if (map->m_lblk >= ee_block) { > > - split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT; > > - if (uninitialized) > > - split_flag1 |= EXT4_EXT_MARK_UNINIT1; > > - if (split_flag & EXT4_EXT_MARK_UNINIT2) > > - split_flag1 |= EXT4_EXT_MARK_UNINIT2; > > + if (uninitialized) { > > + split_flag1 = EXT4_EXT_MARK_UNINIT1; > > + split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT | EXT4_EXT_MARK_UNINIT2); > > + } > > err = ext4_split_extent_at(handle, inode, path, > > map->m_lblk, split_flag1, flags); > > if (err) > > > > -- > 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
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index fd51469..05222d5 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2982,6 +2982,10 @@ static int ext4_split_extent_at(handle_t *handle, newblock = split - ee_block + ext4_ext_pblock(ex); BUG_ON(split < ee_block || split >= (ee_block + ee_len)); + BUG_ON(!ext4_ext_is_uninitialized(ex) && + split_flag & (EXT4_EXT_MAY_ZEROOUT | + EXT4_EXT_MARK_UNINIT1 | + EXT4_EXT_MARK_UNINIT2)); err = ext4_ext_get_access(handle, inode, path + depth); if (err) @@ -3091,18 +3095,24 @@ static int ext4_split_extent(handle_t *handle, if (err) goto out; } - + /* + * Update path is required because previous ext4_split_extent_at() may + * result in split of original leaf or extent zeroout. + */ ext4_ext_drop_refs(path); path = ext4_ext_find_extent(inode, map->m_lblk, path); if (IS_ERR(path)) return PTR_ERR(path); + depth = ext_depth(inode); + ex = path[depth].p_ext; + uninitialized = ext4_ext_is_uninitialized(ex); + split_flag1 = 0; if (map->m_lblk >= ee_block) { - split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT; - if (uninitialized) - split_flag1 |= EXT4_EXT_MARK_UNINIT1; - if (split_flag & EXT4_EXT_MARK_UNINIT2) - split_flag1 |= EXT4_EXT_MARK_UNINIT2; + if (uninitialized) { + split_flag1 = EXT4_EXT_MARK_UNINIT1; + split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT | EXT4_EXT_MARK_UNINIT2); + } err = ext4_split_extent_at(handle, inode, path, map->m_lblk, split_flag1, flags); if (err)
When ext4_split_extent_at() ends up doing zeroout & conversion to initialized instead of split & conversion, ext4_split_extent() gets confused and can wrongly mark the extent back as uninitialized resulting in end IO code getting confused from large unwritten extents and may result in data loss. The example of problematic behavior is: lblk len lblk len ext4_split_extent() (ex=[1000,30,uninit], map=[1010,10]) ext4_split_extent_at() (split [1000,30,uninit] at 1020) ext4_ext_insert_extent() -> ENOSPC ext4_ext_zeroout() -> extent [1000,30] is now initialized ext4_split_extent_at() (split [1000,30,init] at 1010, MARK_UNINIT1 | MARK_UNINIT2) -> extent is split and parts marked as uninitialized Fix the problem by rechecking extent type after the first ext4_split_extent_at() returns. None of split_flags can not be applied to initialized extent so this patch also add BUG_ON to prevent similar issues in future. TESTCASE: https://github.com/dmonakhov/xfstests/commit/1a1c4f337d4d198803436c63a56625b1a78d8a5e Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> --- fs/ext4/extents.c | 22 ++++++++++++++++------ 1 files changed, 16 insertions(+), 6 deletions(-)