* [PATCH 1/1] ext4: remove redundant assignment in ext4_iomap_begin()
@ 2017-11-27 9:21 sunqiuyang
2017-12-21 16:47 ` Theodore Ts'o
0 siblings, 1 reply; 2+ messages in thread
From: sunqiuyang @ 2017-11-27 9:21 UTC (permalink / raw)
To: linux-kernel, linux-fsdevel, linux-ext4; +Cc: sunqiuyang
From: Qiuyang Sun <sunqiuyang@huawei.com>
This line will not change the value of map.m_lblk in any case.
Signed-off-by: Qiuyang Sun <sunqiuyang@huawei.com>
---
fs/ext4/inode.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9f836e2..d4a42b1 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3443,7 +3443,6 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
if (es.es_lblk < map.m_lblk)
offs = map.m_lblk - es.es_lblk;
- map.m_lblk = es.es_lblk + offs;
map.m_len = es.es_len - offs;
delalloc = true;
}
--
2.5.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH 1/1] ext4: remove redundant assignment in ext4_iomap_begin()
2017-11-27 9:21 [PATCH 1/1] ext4: remove redundant assignment in ext4_iomap_begin() sunqiuyang
@ 2017-12-21 16:47 ` Theodore Ts'o
0 siblings, 0 replies; 2+ messages in thread
From: Theodore Ts'o @ 2017-12-21 16:47 UTC (permalink / raw)
To: sunqiuyang; +Cc: linux-kernel, linux-fsdevel, linux-ext4
On Mon, Nov 27, 2017 at 05:21:27PM +0800, sunqiuyang wrote:
> From: Qiuyang Sun <sunqiuyang@huawei.com>
>
> This line will not change the value of map.m_lblk in any case.
I don't see that it is absolutely guaranteed. And if you are
depending on ext4_es_find_delayed_extent() returns, then (a) the
following line which adjusts map.m_len could also be dropped, and (b)
we should add a WARN_ON to make the code robust against future changes
to the above function.
- Ted
>
> Signed-off-by: Qiuyang Sun <sunqiuyang@huawei.com>
> ---
> fs/ext4/inode.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 9f836e2..d4a42b1 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3443,7 +3443,6 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>
> if (es.es_lblk < map.m_lblk)
> offs = map.m_lblk - es.es_lblk;
> - map.m_lblk = es.es_lblk + offs;
> map.m_len = es.es_len - offs;
> delalloc = true;
> }
> --
> 2.5.0
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-12-21 16:47 ` Theodore Ts'o
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