* [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled
@ 2013-07-25 23:42 Zheng Liu
2013-07-29 15:07 ` Zheng Liu
2013-07-29 16:21 ` Theodore Ts'o
0 siblings, 2 replies; 6+ messages in thread
From: Zheng Liu @ 2013-07-25 23:42 UTC (permalink / raw)
To: linux-ext4; +Cc: Jan Kara, Zheng Liu
From: Jan Kara <jack@suse.cz>
Now in ext4_da_page_release_reservation() we remove the entry from es
tree if to_release != 0. But there are two issues. One is that it is
wrong when blocksize != pagesize, another is that we don't need to do
this if ->s_cluster_ratio == 1 because we will remove the entry in
ext4_truncate/ext4_punch_hole. Here we need to do this just because
when ->s_cluster_ratio > 1 we will determine whether we can release
the reserved space according to ext4_find_delalloc_cluster().
This commit tries to fix these problems. Now we remove the entry from
es tree only if ->s_cluster_ratio > 1.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
---
v2:
* fix a typo in comment.
fs/ext4/inode.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ba33c67..2cc97a4 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1387,7 +1387,15 @@ static void ext4_da_page_release_reservation(struct page *page,
curr_off = next_off;
} while ((bh = bh->b_this_page) != head);
- if (to_release) {
+ /*
+ * Here we need to remove the entry from es tree because when bigalloc
+ * is enabled we need to determine whether we can release the reserved
+ * space according to the result of ext4_find_delalloc_cluster().
+ *
+ * If bigalloc is disabled, we don't need to do this here because these
+ * entries in es tree will be removed in ext4_truncate/ext4_punch_hole.
+ */
+ if (sbi->s_cluster_ratio > 1 && to_release) {
lblk = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
ext4_es_remove_extent(inode, lblk, to_release);
}
--
1.7.9.7
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled
2013-07-25 23:42 [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled Zheng Liu
@ 2013-07-29 15:07 ` Zheng Liu
2013-07-29 16:21 ` Theodore Ts'o
1 sibling, 0 replies; 6+ messages in thread
From: Zheng Liu @ 2013-07-29 15:07 UTC (permalink / raw)
To: linux-ext4, tytso; +Cc: Jan Kara, Zheng Liu
On Fri, Jul 26, 2013 at 07:42:06AM +0800, Zheng Liu wrote:
> From: Jan Kara <jack@suse.cz>
>
> Now in ext4_da_page_release_reservation() we remove the entry from es
> tree if to_release != 0. But there are two issues. One is that it is
> wrong when blocksize != pagesize, another is that we don't need to do
> this if ->s_cluster_ratio == 1 because we will remove the entry in
> ext4_truncate/ext4_punch_hole. Here we need to do this just because
> when ->s_cluster_ratio > 1 we will determine whether we can release
> the reserved space according to ext4_find_delalloc_cluster().
>
> This commit tries to fix these problems. Now we remove the entry from
> es tree only if ->s_cluster_ratio > 1.
>
> Signed-off-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Any comment?
Thanks,
- Zheng
> ---
> v2:
> * fix a typo in comment.
>
> fs/ext4/inode.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index ba33c67..2cc97a4 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1387,7 +1387,15 @@ static void ext4_da_page_release_reservation(struct page *page,
> curr_off = next_off;
> } while ((bh = bh->b_this_page) != head);
>
> - if (to_release) {
> + /*
> + * Here we need to remove the entry from es tree because when bigalloc
> + * is enabled we need to determine whether we can release the reserved
> + * space according to the result of ext4_find_delalloc_cluster().
> + *
> + * If bigalloc is disabled, we don't need to do this here because these
> + * entries in es tree will be removed in ext4_truncate/ext4_punch_hole.
> + */
> + if (sbi->s_cluster_ratio > 1 && to_release) {
> lblk = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
> ext4_es_remove_extent(inode, lblk, to_release);
> }
> --
> 1.7.9.7
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled
2013-07-25 23:42 [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled Zheng Liu
2013-07-29 15:07 ` Zheng Liu
@ 2013-07-29 16:21 ` Theodore Ts'o
2013-07-29 17:50 ` Jan Kara
2013-07-29 23:44 ` Zheng Liu
1 sibling, 2 replies; 6+ messages in thread
From: Theodore Ts'o @ 2013-07-29 16:21 UTC (permalink / raw)
To: Zheng Liu; +Cc: linux-ext4, Jan Kara, Zheng Liu
On Fri, Jul 26, 2013 at 07:42:06AM +0800, Zheng Liu wrote:
> From: Jan Kara <jack@suse.cz>
>
> Now in ext4_da_page_release_reservation() we remove the entry from es
> tree if to_release != 0. But there are two issues. One is that it is
> wrong when blocksize != pagesize,
The commit description says that this is wrong, but I don't see
anything in the patch which addresses this. And could you state what
the impact is of this wrongness?
Thanks,
- Ted
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled
2013-07-29 16:21 ` Theodore Ts'o
@ 2013-07-29 17:50 ` Jan Kara
2013-07-29 23:44 ` Zheng Liu
1 sibling, 0 replies; 6+ messages in thread
From: Jan Kara @ 2013-07-29 17:50 UTC (permalink / raw)
To: Theodore Ts'o; +Cc: Zheng Liu, linux-ext4, Jan Kara, Zheng Liu
On Mon 29-07-13 12:21:51, Ted Tso wrote:
> On Fri, Jul 26, 2013 at 07:42:06AM +0800, Zheng Liu wrote:
> > From: Jan Kara <jack@suse.cz>
> >
> > Now in ext4_da_page_release_reservation() we remove the entry from es
> > tree if to_release != 0. But there are two issues. One is that it is
> > wrong when blocksize != pagesize,
>
> The commit description says that this is wrong, but I don't see
> anything in the patch which addresses this. And could you state what
> the impact is of this wrongness?
Well, this wrongness actually shouldn't have any real impact - for
blocksize < pagesize the extent tree isn't used while truncate_pagecache()
is running and ext4_truncate() then removes the whole truncated range from
the tree again which hides any problems in
ext4_da_page_release_reservation(). When bigalloc is used, we use the
extent tree during truncate_pagecache() but to_release is always == 1 and
thus the problem doesn't exist.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled
2013-07-29 16:21 ` Theodore Ts'o
2013-07-29 17:50 ` Jan Kara
@ 2013-07-29 23:44 ` Zheng Liu
2013-07-30 16:14 ` Jan Kara
1 sibling, 1 reply; 6+ messages in thread
From: Zheng Liu @ 2013-07-29 23:44 UTC (permalink / raw)
To: Theodore Ts'o; +Cc: linux-ext4, Jan Kara, Zheng Liu
On Mon, Jul 29, 2013 at 12:21:51PM -0400, Theodore Ts'o wrote:
> On Fri, Jul 26, 2013 at 07:42:06AM +0800, Zheng Liu wrote:
> > From: Jan Kara <jack@suse.cz>
> >
> > Now in ext4_da_page_release_reservation() we remove the entry from es
> > tree if to_release != 0. But there are two issues. One is that it is
> > wrong when blocksize != pagesize,
>
> The commit description says that this is wrong, but I don't see
> anything in the patch which addresses this. And could you state what
> the impact is of this wrongness?
Sorry for my bad description. As Jan said, this patch doesn't address
any issue. It just makes the code clearly. After applied this patch,
I still get the warning messages from ext4_da_release_space running
xfstests #74 when blocksize = 1k.
Thanks,
- Zheng
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled
2013-07-29 23:44 ` Zheng Liu
@ 2013-07-30 16:14 ` Jan Kara
0 siblings, 0 replies; 6+ messages in thread
From: Jan Kara @ 2013-07-30 16:14 UTC (permalink / raw)
To: Zheng Liu; +Cc: Theodore Ts'o, linux-ext4, Jan Kara, Zheng Liu
On Tue 30-07-13 07:44:25, Zheng Liu wrote:
> Sorry for my bad description. As Jan said, this patch doesn't address
> any issue. It just makes the code clearly. After applied this patch,
> I still get the warning messages from ext4_da_release_space running
> xfstests #74 when blocksize = 1k.
Interesting. I never noticed those but now I see them as well. Dave Jones
also reported this problem (although he didn't mention 1KB blocksize).
I'll try to have a look into it.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 6+ messages in thread
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2013-07-25 23:42 [PATCH v2] ext4: remove the entry from es tree when bigalloc is enabled Zheng Liu
2013-07-29 15:07 ` Zheng Liu
2013-07-29 16:21 ` Theodore Ts'o
2013-07-29 17:50 ` Jan Kara
2013-07-29 23:44 ` Zheng Liu
2013-07-30 16:14 ` Jan Kara
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