Hi Ted,
One minor comment below for the note.
On 02/23/2013 01:55 AM, Theodore Ts'o wrote:
[snip]
> From 7d46e5051453b2c4dfac4e31ae1afb30064cc404 Mon Sep 17 00:00:00 2001
> From: Eryu Guan <guaneryu@xxxxxxxxx>
> Date: Fri, 22 Feb 2013 12:54:36 -0500
> Subject: [PATCH] ext4: no need to remove extent if len is 0 in
> ext4_es_remove_extent()
>
> len is 0 means no extent needs to be removed, so return immediately.
> Otherwise it could trigger the following BUG_ON() in
> ext4_es_remove_extent()
>
> end = lblk + len - 1;
> BUG_ON(end < lblk);
>
> This could be reproduced by a simple truncate(1) command by an
> unprivileged user
>
> truncate -s $(($((2**32 - 1)) * 4096)) /mnt/ext4/testfile
>
> The same is true for __es_insert_extent().
>
> Patched kernel passed xfstests regression test.
>
> Signed-off-by: Eryu Guan <guaneryu@xxxxxxxxx>
> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
> Reviewed-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
> ---
> fs/ext4/extents_status.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index 9f1380e..2be245b 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -392,6 +392,9 @@ static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
> struct rb_node *parent = NULL;
> struct extent_status *es;
>
> + if (!len)
> + return 0;
> +
This will cause a compile error because we don't define a 'len'
variable. But I have noticed that you have fixed it in latest dev
branch. So just for the note.
Otherwise the patch looks good.
Reviewed-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
Thanks for fixing it,
- Zheng
> while (*p) {
> parent = *p;
> es = rb_entry(parent, struct extent_status, rb_node);
> @@ -456,6 +459,9 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
> es_debug("add [%u/%u) %llu %llx to extent status tree of inode %lu\n",
> lblk, len, pblk, status, inode->i_ino);
>
> + if (!len)
> + return 0;
> +
> BUG_ON(end < lblk);
>
> newes.es_lblk = lblk;
> @@ -649,6 +655,9 @@ int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
> es_debug("remove [%u/%u) from extent status tree of inode %lu\n",
> lblk, len, inode->i_ino);
>
> + if (!len)
> + return err;
> +
> end = lblk + len - 1;
> BUG_ON(end < lblk);
>
>
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