Hello everyone,
Today I tried to build a kernel with btrfs enabled on ARM, then when
linking I met such an error:
```
fs/built-in.o: In function `scrub_bio_end_io_worker':
acl.c:(.text+0x2f0450): undefined reference to `__aeabi_uldivmod'
fs/built-in.o: In function `scrub_extent_for_parity':
acl.c:(.text+0x2f0bcc): undefined reference to `__aeabi_uldivmod'
fs/built-in.o: In function `scrub_raid56_parity':
acl.c:(.text+0x2f12a8): undefined reference to `__aeabi_uldivmod'
acl.c:(.text+0x2f15c4): undefined reference to `__aeabi_uldivmod'
```
These functions are found at fs/btrfs/scrub.c .
After disabling btrfs the kernel is successfully built.
For this problem, see also [1], which used to be a similar bug in PL330
driver code.
[1] https://patchwork.kernel.org/patch/5299081/
Thanks,
Icenowy
On Sat, Apr 8, 2017 at 1:02 PM, Icenowy Zheng <[email protected]> wrote:
> Hello everyone,
> Today I tried to build a kernel with btrfs enabled on ARM, then when linking
> I met such an error:
>
> ```
> fs/built-in.o: In function `scrub_bio_end_io_worker':
> acl.c:(.text+0x2f0450): undefined reference to `__aeabi_uldivmod'
> fs/built-in.o: In function `scrub_extent_for_parity':
> acl.c:(.text+0x2f0bcc): undefined reference to `__aeabi_uldivmod'
> fs/built-in.o: In function `scrub_raid56_parity':
> acl.c:(.text+0x2f12a8): undefined reference to `__aeabi_uldivmod'
> acl.c:(.text+0x2f15c4): undefined reference to `__aeabi_uldivmod'
> ```
>
> These functions are found at fs/btrfs/scrub.c .
>
> After disabling btrfs the kernel is successfully built.
I see the same error with ARM imx_v6_v7_defconfig + btrfs support.
Looks like it is caused by commit 7d0ef8b4dbbd220 ("Btrfs: update
scrub_parity to use u64 stripe_len").
On Sat, Apr 08, 2017 at 02:45:34PM -0300, Fabio Estevam wrote:
> On Sat, Apr 8, 2017 at 1:02 PM, Icenowy Zheng <[email protected]> wrote:
> > Hello everyone,
> > Today I tried to build a kernel with btrfs enabled on ARM, then when linking
> > I met such an error:
> >
> > ```
> > fs/built-in.o: In function `scrub_bio_end_io_worker':
> > acl.c:(.text+0x2f0450): undefined reference to `__aeabi_uldivmod'
> > fs/built-in.o: In function `scrub_extent_for_parity':
> > acl.c:(.text+0x2f0bcc): undefined reference to `__aeabi_uldivmod'
> > fs/built-in.o: In function `scrub_raid56_parity':
> > acl.c:(.text+0x2f12a8): undefined reference to `__aeabi_uldivmod'
> > acl.c:(.text+0x2f15c4): undefined reference to `__aeabi_uldivmod'
> > ```
> >
> > These functions are found at fs/btrfs/scrub.c .
> >
> > After disabling btrfs the kernel is successfully built.
>
> I see the same error with ARM imx_v6_v7_defconfig + btrfs support.
>
> Looks like it is caused by commit 7d0ef8b4dbbd220 ("Btrfs: update
> scrub_parity to use u64 stripe_len").
+1, my bisect just finished, same bad commit.
--
⢀⣴⠾⠻⢶⣦⠀ Meow!
⣾⠁⢠⠒⠀⣿⡁
⢿⡄⠘⠷⠚⠋⠀ Collisions shmolisions, let's see them find a collision or second
⠈⠳⣄⠀⠀⠀⠀ preimage for double rot13!
Unbreaks ARM and possibly other 32-bit architectures.
Fixes: 7d0ef8b4d: Btrfs: update scrub_parity to use u64 stripe_len
Reported-by: Icenowy Zheng <[email protected]>
Signed-off-by: Adam Borowski <[email protected]>
---
You'd probably want to squash this with Liu's commit, to be nice to future
bisects.
Tested on amd64 where all is fine, and on arm (Odroid-U2) where scrub
sometimes works, but, like most operations, randomly dies with some badness
that doesn't look related: io_schedule, kunmap_high. That badness wasn't
there in 4.11-rc5, needs investigating, but since it's not connected to our
issue at hand, I consider this patch sort-of tested.
fs/btrfs/scrub.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index b6fe1cd08048..95372e3679f3 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2407,7 +2407,7 @@ static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
start -= sparity->logic_start;
start = div64_u64_rem(start, sparity->stripe_len, &offset);
- offset /= sectorsize;
+ do_div(offset, sectorsize);
nsectors = (int)len / sectorsize;
if (offset + nsectors <= sparity->nsectors) {
--
2.11.0
On Sat, Apr 08, 2017 at 11:07:37PM +0200, Adam Borowski wrote:
> Unbreaks ARM and possibly other 32-bit architectures.
Turns out those "other 32-bit architectures" happen to include i386.
A modular build:
ERROR: "__udivdi3" [fs/btrfs/btrfs.ko] undefined!
With the patch, i386 builds fine.
> Tested on amd64 where all is fine, and on arm (Odroid-U2) where scrub
> sometimes works, but, like most operations, randomly dies with some badness
> that doesn't look related: io_schedule, kunmap_high. That badness wasn't
> there in 4.11-rc5, needs investigating, but since it's not connected to our
> issue at hand, I consider this patch sort-of tested.
Looks like current -next is pretty broken: while amd64 is ok, on an i386 box
(non-NX Pentium 4) it hangs very early during boot, way before filesystem
modules would be loaded. Qemu boots but has random hangs.
So it looks like it's compile only for now...
--
⢀⣴⠾⠻⢶⣦⠀ Meow!
⣾⠁⢠⠒⠀⣿⡁
⢿⡄⠘⠷⠚⠋⠀ Collisions shmolisions, let's see them find a collision or second
⠈⠳⣄⠀⠀⠀⠀ preimage for double rot13!
On Sun, Apr 09, 2017 at 05:58:54AM +0200, Adam Borowski wrote:
> On Sat, Apr 08, 2017 at 11:07:37PM +0200, Adam Borowski wrote:
> > Unbreaks ARM and possibly other 32-bit architectures.
>
> Turns out those "other 32-bit architectures" happen to include i386.
>
> A modular build:
> ERROR: "__udivdi3" [fs/btrfs/btrfs.ko] undefined!
> With the patch, i386 builds fine.
>
> > Tested on amd64 where all is fine, and on arm (Odroid-U2) where scrub
> > sometimes works, but, like most operations, randomly dies with some badness
> > that doesn't look related: io_schedule, kunmap_high. That badness wasn't
> > there in 4.11-rc5, needs investigating, but since it's not connected to our
> > issue at hand, I consider this patch sort-of tested.
>
> Looks like current -next is pretty broken: while amd64 is ok, on an i386 box
> (non-NX Pentium 4) it hangs very early during boot, way before filesystem
> modules would be loaded. Qemu boots but has random hangs.
A non-modular i386_defconfig + btrfs of -next is ok; whatever the problem
is, it's not relevant to our division build failure in scrub.
But, it looks like parity scrub is ${EXPLETIVE}ed on 32-bit. Not just on
-next, also on 4.11-rc5 and 4.9. Test script I used is attached, although
it's enough to just scrub a kosher filesystem without even damaging it.
On 64-bit it mostly works, but still warns about bogus unrecoverable errors
when in fact it succeeded.
Thus, I'd recommend:
* applying this patch to at least make it compile
* taking steps to warn outside people about RAID5/6
Let's discuss the rest in another thread, it's no longer interesting to ARM
people, they just want no build failures.
--
⢀⣴⠾⠻⢶⣦⠀ Meow!
⣾⠁⢠⠒⠀⣿⡁
⢿⡄⠘⠷⠚⠋⠀ Collisions shmolisions, let's see them find a collision or second
⠈⠳⣄⠀⠀⠀⠀ preimage for double rot13!
On Sat, Apr 08, 2017 at 11:07:37PM +0200, Adam Borowski wrote:
> Unbreaks ARM and possibly other 32-bit architectures.
>
> Fixes: 7d0ef8b4d: Btrfs: update scrub_parity to use u64 stripe_len
> Reported-by: Icenowy Zheng <[email protected]>
> Signed-off-by: Adam Borowski <[email protected]>
> ---
> You'd probably want to squash this with Liu's commit, to be nice to future
> bisects.
Thanks for finding it!
> Tested on amd64 where all is fine, and on arm (Odroid-U2) where scrub
> sometimes works, but, like most operations, randomly dies with some badness
> that doesn't look related: io_schedule, kunmap_high. That badness wasn't
> there in 4.11-rc5, needs investigating, but since it's not connected to our
> issue at hand, I consider this patch sort-of tested.
>
> fs/btrfs/scrub.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index b6fe1cd08048..95372e3679f3 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -2407,7 +2407,7 @@ static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
>
> start -= sparity->logic_start;
> start = div64_u64_rem(start, sparity->stripe_len, &offset);
> - offset /= sectorsize;
> + do_div(offset, sectorsize);
I'll use the div_u64 helper instead, I don't want to reintroduce do_div
to fs/btrfs , for-next will be updated in a minute.
On 2017-04-08 17:07, Adam Borowski wrote:
> Unbreaks ARM and possibly other 32-bit architectures.
>
> Fixes: 7d0ef8b4d: Btrfs: update scrub_parity to use u64 stripe_len
> Reported-by: Icenowy Zheng <[email protected]>
> Signed-off-by: Adam Borowski <[email protected]>
> ---
> You'd probably want to squash this with Liu's commit, to be nice to future
> bisects.
>
> Tested on amd64 where all is fine, and on arm (Odroid-U2) where scrub
> sometimes works, but, like most operations, randomly dies with some badness
> that doesn't look related: io_schedule, kunmap_high. That badness wasn't
> there in 4.11-rc5, needs investigating, but since it's not connected to our
> issue at hand, I consider this patch sort-of tested.
>
> fs/btrfs/scrub.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index b6fe1cd08048..95372e3679f3 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -2407,7 +2407,7 @@ static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
>
> start -= sparity->logic_start;
> start = div64_u64_rem(start, sparity->stripe_len, &offset);
> - offset /= sectorsize;
> + do_div(offset, sectorsize);
> nsectors = (int)len / sectorsize;
>
> if (offset + nsectors <= sparity->nsectors) {
>
Also fixes things on:
32-bit MIPS (eb and el variants)
32-bit SPARC
32-bit PPC
You can add my Tested-by if you want.
On Sat, Apr 08, 2017 at 11:07:37PM +0200, Adam Borowski wrote:
> Unbreaks ARM and possibly other 32-bit architectures.
>
Thanks a lot for the fix.
Reviewed-by: Liu Bo <[email protected]>
Thanks,
-liubo
> Fixes: 7d0ef8b4d: Btrfs: update scrub_parity to use u64 stripe_len
> Reported-by: Icenowy Zheng <[email protected]>
> Signed-off-by: Adam Borowski <[email protected]>
> ---
> You'd probably want to squash this with Liu's commit, to be nice to future
> bisects.
>
> Tested on amd64 where all is fine, and on arm (Odroid-U2) where scrub
> sometimes works, but, like most operations, randomly dies with some badness
> that doesn't look related: io_schedule, kunmap_high. That badness wasn't
> there in 4.11-rc5, needs investigating, but since it's not connected to our
> issue at hand, I consider this patch sort-of tested.
>
> fs/btrfs/scrub.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index b6fe1cd08048..95372e3679f3 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -2407,7 +2407,7 @@ static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
>
> start -= sparity->logic_start;
> start = div64_u64_rem(start, sparity->stripe_len, &offset);
> - offset /= sectorsize;
> + do_div(offset, sectorsize);
> nsectors = (int)len / sectorsize;
>
> if (offset + nsectors <= sparity->nsectors) {
> --
> 2.11.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html