* [PATCH] ext4: add WARN_ON to check the length of allocated blocks
@ 2013-03-24 9:42 Zheng Liu
2013-03-24 18:23 ` Theodore Ts'o
0 siblings, 1 reply; 3+ messages in thread
From: Zheng Liu @ 2013-03-24 9:42 UTC (permalink / raw)
To: linux-ext4; +Cc: Zheng Liu
From: Zheng Liu <wenqing.lz@taobao.com>
In this commit (921f266b) a sanity check is added in map_blocks to make
sure 'retval == map->m_len'. But we need to define a macro to enable
it. This commit uses a WARN_ON to do the same thing.
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
---
fs/ext4/inode.c | 27 +++------------------------
1 file changed, 3 insertions(+), 24 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 85e41a2..4513e9a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -613,14 +613,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
int ret;
unsigned long long status;
-#ifdef ES_AGGRESSIVE_TEST
- if (retval != map->m_len) {
- printk("ES len assertation failed for inode: %lu "
- "retval %d != map->m_len %d "
- "in %s (lookup)\n", inode->i_ino, retval,
- map->m_len, __func__);
- }
-#endif
+ WARN_ON(retval != map->m_len);
status = map->m_flags & EXT4_MAP_UNWRITTEN ?
EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
@@ -714,14 +707,7 @@ found:
int ret;
unsigned long long status;
-#ifdef ES_AGGRESSIVE_TEST
- if (retval != map->m_len) {
- printk("ES len assertation failed for inode: %lu "
- "retval %d != map->m_len %d "
- "in %s (allocation)\n", inode->i_ino, retval,
- map->m_len, __func__);
- }
-#endif
+ WARN_ON(retval != map->m_len);
/*
* If the extent has been zeroed out, we don't need to update
@@ -2030,14 +2016,7 @@ add_delayed:
int ret;
unsigned long long status;
-#ifdef ES_AGGRESSIVE_TEST
- if (retval != map->m_len) {
- printk("ES len assertation failed for inode: %lu "
- "retval %d != map->m_len %d "
- "in %s (lookup)\n", inode->i_ino, retval,
- map->m_len, __func__);
- }
-#endif
+ WARN_ON(retval != map->m_len);
status = map->m_flags & EXT4_MAP_UNWRITTEN ?
EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
--
1.7.12.rc2.18.g61b472e
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] ext4: add WARN_ON to check the length of allocated blocks
2013-03-24 9:42 [PATCH] ext4: add WARN_ON to check the length of allocated blocks Zheng Liu
@ 2013-03-24 18:23 ` Theodore Ts'o
2013-03-25 2:50 ` Zheng Liu
0 siblings, 1 reply; 3+ messages in thread
From: Theodore Ts'o @ 2013-03-24 18:23 UTC (permalink / raw)
To: Zheng Liu; +Cc: linux-ext4, Zheng Liu
On Sun, Mar 24, 2013 at 05:42:53PM +0800, Zheng Liu wrote:
> From: Zheng Liu <wenqing.lz@taobao.com>
>
> In this commit (921f266b) a sanity check is added in map_blocks to make
> sure 'retval == map->m_len'. But we need to define a macro to enable
> it. This commit uses a WARN_ON to do the same thing.
>
> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
You and Dmitry were the ones who using originally these these checks
to fix the bugs here; if we think the code is clean enough that we
don't need the debugging information with the inode number, length,
etc., then sure, we could use the unconditionally defined WARN_ON().
If we wanted to be really paranoid and give ourselves the maximal
amount of debugging information, we could of course do something like
this:
if (retval != map->m_len) {
ext4_warning(inode->i_sb, "ES len assertation failed for inode: %lu retval %d != map->m_len %d\n", inode->i_ino, retval,
map->m_len);
WARN_ON(1);
}
This way, we get the stack dump, the file system device, and all of
the debugging information. The tradeoff is we're bloating the code
size a bit.
The question is really how confident are we that we've found all of
the potential bugs here. If we think that there's a chance we might
trip this check in the future, sometimes it's good to print as much
information as possible, especially if it's hard to create a
reproduction on demand.
What do you think?
- Ted
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] ext4: add WARN_ON to check the length of allocated blocks
2013-03-24 18:23 ` Theodore Ts'o
@ 2013-03-25 2:50 ` Zheng Liu
0 siblings, 0 replies; 3+ messages in thread
From: Zheng Liu @ 2013-03-25 2:50 UTC (permalink / raw)
To: Theodore Ts'o; +Cc: linux-ext4, Zheng Liu
On Sun, Mar 24, 2013 at 02:23:18PM -0400, Theodore Ts'o wrote:
> On Sun, Mar 24, 2013 at 05:42:53PM +0800, Zheng Liu wrote:
> > From: Zheng Liu <wenqing.lz@taobao.com>
> >
> > In this commit (921f266b) a sanity check is added in map_blocks to make
> > sure 'retval == map->m_len'. But we need to define a macro to enable
> > it. This commit uses a WARN_ON to do the same thing.
> >
> > Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
>
> You and Dmitry were the ones who using originally these these checks
> to fix the bugs here;
Yes, I use this check to fix bug.
> if we think the code is clean enough that we
> don't need the debugging information with the inode number, length,
> etc., then sure, we could use the unconditionally defined WARN_ON().
>
> If we wanted to be really paranoid and give ourselves the maximal
> amount of debugging information, we could of course do something like
> this:
>
> if (retval != map->m_len) {
> ext4_warning(inode->i_sb, "ES len assertation failed for inode: %lu retval %d != map->m_len %d\n", inode->i_ino, retval,
> map->m_len);
> WARN_ON(1);
> }
I think this is better.
>
> This way, we get the stack dump, the file system device, and all of
> the debugging information. The tradeoff is we're bloating the code
> size a bit.
>
> The question is really how confident are we that we've found all of
> the potential bugs here. If we think that there's a chance we might
> trip this check in the future, sometimes it's good to print as much
> information as possible, especially if it's hard to create a
> reproduction on demand.
>
> What do you think?
In my sand box, after fixed the bug, I never see this warning again.
But I do believe we'd better leave it here to give us an opportunity to
fix some potential bugs.
Thanks,
- Zheng
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-03-24 9:42 [PATCH] ext4: add WARN_ON to check the length of allocated blocks Zheng Liu
2013-03-24 18:23 ` Theodore Ts'o
2013-03-25 2:50 ` Zheng Liu
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