2023-01-03 02:13:07

by zhanchengbin

Subject: [PATCH] ext4: fix inode tree inconsistency caused by ENOMEM

If ENOMEM fails when the extent is splitting, we need to restore the length
of the split extent.
In the ext4_split_extent_at function, only in ext4_ext_create_new_leaf will
it alloc memory and change the shape of the extent tree,even if an ENOMEM
is returned at this time, the extent tree is still self-consistent, Just
restore the split extent lens in the function ext4_split_extent_at.

ext4_split_extent_at
ext4_ext_insert_extent
ext4_ext_create_new_leaf
1)ext4_ext_split
ext4_find_extent
2)ext4_ext_grow_indepth
ext4_find_extent

Signed-off-by: zhanchengbin <[email protected]>
---
Another solution is to add the __GFP_NOFAIL flag when allocating memory.

fs/ext4/extents.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9de1c9d1a13d..3559ea6b0781 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3251,7 +3251,7 @@ static int ext4_split_extent_at(handle_t *handle,
ext4_ext_mark_unwritten(ex2);

err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
- if (err != -ENOSPC && err != -EDQUOT)
+ if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
goto out;

if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
--
2.31.1

2023-01-03 10:32:16

by Jan Kara

Subject: Re: [PATCH] ext4: fix inode tree inconsistency caused by ENOMEM

On Tue 03-01-23 10:28:12, zhanchengbin wrote:
> If ENOMEM fails when the extent is splitting, we need to restore the length
> of the split extent.
> In the ext4_split_extent_at function, only in ext4_ext_create_new_leaf will
> it alloc memory and change the shape of the extent tree,even if an ENOMEM
> is returned at this time, the extent tree is still self-consistent, Just
> restore the split extent lens in the function ext4_split_extent_at.
>
> ext4_split_extent_at
> ext4_ext_insert_extent
> ext4_ext_create_new_leaf
> 1)ext4_ext_split
> ext4_find_extent
> 2)ext4_ext_grow_indepth
> ext4_find_extent
>
> Signed-off-by: zhanchengbin <[email protected]>

Yeah that should work. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

Honza

> ---
> Another solution is to add the __GFP_NOFAIL flag when allocating memory.
>
> fs/ext4/extents.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 9de1c9d1a13d..3559ea6b0781 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3251,7 +3251,7 @@ static int ext4_split_extent_at(handle_t *handle,
> ext4_ext_mark_unwritten(ex2);
>
> err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
> - if (err != -ENOSPC && err != -EDQUOT)
> + if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
> goto out;
>
> if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
> --
> 2.31.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR

2023-02-19 05:42:05

by Theodore Ts'o

Subject: Re: [PATCH] ext4: fix inode tree inconsistency caused by ENOMEM

On Tue, 3 Jan 2023 10:28:12 +0800, zhanchengbin wrote:
> If ENOMEM fails when the extent is splitting, we need to restore the length
> of the split extent.
> In the ext4_split_extent_at function, only in ext4_ext_create_new_leaf will
> it alloc memory and change the shape of the extent tree,even if an ENOMEM
> is returned at this time, the extent tree is still self-consistent, Just
> restore the split extent lens in the function ext4_split_extent_at.
>
> [...]

Applied, thanks!

[1/1] ext4: fix inode tree inconsistency caused by ENOMEM
commit: 3f5424790d4377839093b68c12b130077a4e4510

Best regards,
--
Theodore Ts'o <[email protected]>