There are enough credits reserved for most dioread_nolock writes;
however, if the extent tree is sufficiently deep, and/or quota is
enabled, the code was not allowing for all eventualities when
reserving journal credits for the unwritten extent conversion.
This problem can be seen using xfstests ext4/034:
WARNING: CPU: 1 PID: 257 at fs/ext4/ext4_jbd2.c:271 __ext4_handle_dirty_metadata+0x10c/0x180
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
RIP: 0010:__ext4_handle_dirty_metadata+0x10c/0x180
...
EXT4-fs: ext4_free_blocks:4938: aborting transaction: error 28 in __ext4_handle_dirty_metadata
EXT4: jbd2_journal_dirty_metadata failed: handle type 11 started at line 4921, credits 4/0, errcode -28
EXT4-fs error (device dm-1) in ext4_free_blocks:4950: error 28
Signed-off-by: Theodore Ts'o <[email protected]>
Cc: [email protected]
---
fs/ext4/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9affabd07682..165ff331d998 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2778,7 +2778,8 @@ static int ext4_writepages(struct address_space *mapping,
* We may need to convert up to one extent per block in
* the page and we may dirty the inode.
*/
- rsv_blocks = 1 + (PAGE_SIZE >> inode->i_blkbits);
+ rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
+ PAGE_SIZE >> inode->i_blkbits);
}
/*
--
2.19.1
</[email protected]>
On Mon, Dec 24, 2018 at 9:36 PM Theodore Ts'o <[email protected]> wrote:
>
> There are enough credits reserved for most dioread_nolock writes;
> however, if the extent tree is sufficiently deep, and/or quota is
> enabled, the code was not allowing for all eventualities when
> reserving journal credits for the unwritten extent conversion.
>
> This problem can be seen using xfstests ext4/034:
>
> WARNING: CPU: 1 PID: 257 at fs/ext4/ext4_jbd2.c:271 __ext4_handle_dirty_metadata+0x10c/0x180
> Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
> RIP: 0010:__ext4_handle_dirty_metadata+0x10c/0x180
> ...
> EXT4-fs: ext4_free_blocks:4938: aborting transaction: error 28 in __ext4_handle_dirty_metadata
> EXT4: jbd2_journal_dirty_metadata failed: handle type 11 started at line 4921, credits 4/0, errcode -28
> EXT4-fs error (device dm-1) in ext4_free_blocks:4950: error 28
>
I had a patch[1] to address the problem but with adding reservation
only when we need to (in ext4_ext_try_to_merge_up).
I'm fine with either way.
Reviewed-by: Liu Bo <[email protected]>
BTW, the ext4/034 may need to be updated with the correct patch title/commit.
thanks,
liubo
[1]:
https://patchwork.ozlabs.org/patch/991794/
> Signed-off-by: Theodore Ts'o <[email protected]>
> Cc: [email protected]
> ---
> fs/ext4/inode.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 9affabd07682..165ff331d998 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -2778,7 +2778,8 @@ static int ext4_writepages(struct address_space *mapping,
> * We may need to convert up to one extent per block in
> * the page and we may dirty the inode.
> */
> - rsv_blocks = 1 + (PAGE_SIZE >> inode->i_blkbits);
> + rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
> + PAGE_SIZE >> inode->i_blkbits);
> }
>
> /*
> --
> 2.19.1
>
On Tue, Dec 25, 2018 at 04:10:25PM -0800, Liu Bo wrote:
>
> I had a patch[1] to address the problem but with adding reservation
> only when we need to (in ext4_ext_try_to_merge_up).
Sorry, I had forgotten that you had that patch pending. I believe
that merging up isn't the only case we need to worry about, though.
For example, if we write into the middle of a larger unwritten region,
we might havec to change a single region into three regions, which
might require a node split --- and in that case, it's not optional, as
would be in the try_to_merge_up situation. If we don't have enough
credits to do a node split our only choices would be mark the file
system as corrupted, or to fail the write with ENOSPC (which would be
very confusing to the user/application).
Cheers,
- Ted
On Tue, Dec 25, 2018 at 8:07 PM Theodore Y. Ts'o <[email protected]> wrote:
>
> On Tue, Dec 25, 2018 at 04:10:25PM -0800, Liu Bo wrote:
> >
> > I had a patch[1] to address the problem but with adding reservation
> > only when we need to (in ext4_ext_try_to_merge_up).
>
> Sorry, I had forgotten that you had that patch pending. I believe
> that merging up isn't the only case we need to worry about, though.
> For example, if we write into the middle of a larger unwritten region,
> we might havec to change a single region into three regions, which
> might require a node split --- and in that case, it's not optional, as
> would be in the try_to_merge_up situation. If we don't have enough
> credits to do a node split our only choices would be mark the file
> system as corrupted, or to fail the write with ENOSPC (which would be
> very confusing to the user/application).
>
I see it now, thanks for the explanation.
thanks,
liubo
> Cheers,
>
> - Ted