Re: [PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

Re: [PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian Garcia Casado]

Hi Andreas,

I am terribly sorry for the confusion and the noise in my previous email. 
I completely misread your message and drafted a rushed reply by mistake. 
Please disregard my previous "Thanks for applying" message.

You are absolutely right. Adding the __rcu annotation only exposes the 
200 sparse warnings without fixing the actual underlying RCU dereferences, 
which is indeed not very useful for upstream yet.

I will go back and work on a proper patch series to cleanly address those 
underlying RCU dereference warnings in fs/gfs2/ before submitting again.

My sincere apologies for the noise, and thank you for your patience and 
valuable feedback.

Best regards,
Adrian

Re: [PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian Garcia Casado]

Hi Andreas,

Thanks for applying the patch!

For the record, I have successfully boot-tested the patched v7.2-rc4+
kernel on bare-metal x86_64 (Debian 13 native on an ASUS Vivobook).

To stress-test the kernel stability under load, I ran some heavy workloads:
- A standalone loopback mount of GFS2 (using lock_nolock) with I/O stress
  tests (100+ concurrent files).
- A full multi-threaded compilation of the PCSX2 emulator (using CMake
  and Ninja) with all CPU cores sustained at 100% load.

The system behaved completely stable with no deadlocks, hangs, or OOM.

Tested-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>

Best regards,
Adrian

Re: [PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian Garcia Casado]

Hi Andreas,

Thanks for applying the patch!

For the record, I have successfully boot-tested the patched v7.2-rc4+
kernel on bare-metal x86_64 (Debian 13 native on an ASUS Vivobook).

To stress-test the kernel stability under load, I ran some heavy workloads:
- A standalone loopback mount of GFS2 (using lock_nolock) with I/O stress
  tests (100+ concurrent files).
- A full multi-threaded compilation of the PCSX2 emulator (using CMake
  and Ninja) with all CPU cores sustained at 100% load.

The system behaved completely stable with no deadlocks, hangs, or OOM.

Tested-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>

Best regards,
Adrian

[PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian Garcia Casado]

Signed-off-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
---
 fs/gfs2/incore.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 614657778..16df75336 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -392,7 +392,7 @@ struct gfs2_inode {
 	u64 i_generation;
 	u64 i_eattr;
 	unsigned long i_flags;		/* GIF_... */
-	struct gfs2_glock *i_gl;
+	struct gfs2_glock __rcu *i_gl;
 	struct gfs2_holder i_iopen_gh;
 	struct gfs2_qadata *i_qadata; /* quota allocation data */
 	struct gfs2_holder i_rgd_gh;
-- 
2.47.3

[PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian Garcia Casado]

In gfs2_inode_lookup() and other parts of the GFS2 filesystem,
ip->i_gl is accessed and dereferenced via RCU helpers like
rcu_dereference_check() and rcu_access_pointer(). However, the
actual i_gl pointer in struct gfs2_inode was never annotated
with __rcu in incore.h.

This missing annotation causes Sparse to throw multiple
"incompatible types in comparison expression (different address spaces)"
warnings and compilation-blocking errors under strict static analysis builds.

Fix this by adding the __rcu annotation to i_gl in struct gfs2_inode.

Signed-off-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
Tested-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
---

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 6146577..16df753 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -392,7 +392,7 @@ struct gfs2_inode {
 	u64 i_generation;
 	u64 i_eattr;
 	unsigned long i_flags;		/* GIF_... */
-	struct gfs2_glock *i_gl;
+	struct gfs2_glock __rcu *i_gl;
 	struct gfs2_holder i_iopen_gh;
 	struct gfs2_qadata *i_qadata; /* quota allocation data */
 	struct gfs2_holder i_rgd_gh;

Re: [PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Andreas Gruenbacher]

On Tue, Jun 30, 2026 at 12:03 PM Adrian Garcia Casado
<adriangarciacasado42@gmail.com> wrote:
> In gfs2_inode_lookup() and other parts of the GFS2 filesystem,
> ip->i_gl is accessed and dereferenced via RCU helpers like
> rcu_dereference_check() and rcu_access_pointer(). However, the
> actual i_gl pointer in struct gfs2_inode was never annotated
> with __rcu in incore.h.
>
> This missing annotation causes Sparse to throw multiple
> "incompatible types in comparison expression (different address spaces)"
> warnings and compilation-blocking errors under strict static analysis builds.

Indeed, there are two sparse errors related to i_gl.

> Fix this by adding the __rcu annotation to i_gl in struct gfs2_inode.

With this fix, I get about 200 sparse warnings instead of the two
errors. So thanks for pointing out that there are errors, but without
fixing any of the underlying problems, this patch isn't very useful.

Andreas

> Signed-off-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
> Tested-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
> ---
>
> diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
> index 6146577..16df753 100644
> --- a/fs/gfs2/incore.h
> +++ b/fs/gfs2/incore.h
> @@ -392,7 +392,7 @@ struct gfs2_inode {
>         u64 i_generation;
>         u64 i_eattr;
>         unsigned long i_flags;          /* GIF_... */
> -       struct gfs2_glock *i_gl;
> +       struct gfs2_glock __rcu *i_gl;
>         struct gfs2_holder i_iopen_gh;
>         struct gfs2_qadata *i_qadata; /* quota allocation data */
>         struct gfs2_holder i_rgd_gh;

Applied, thanks.



Andreas

Re: [PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Andreas Gruenbacher]

On Fri, Jul 24, 2026 at 6:05 PM Adrián García Casado
<adriangarciacasado42@gmail.com> wrote:
> Hi Andreas,
>
> Thanks for applying the patch!

No, I'm not applying that patch. As I said, it's not really fixing
anything, it's only trading two errors against 200 warnings.

> For the record, I have successfully boot-tested the patched v7.2-rc4+
> kernel on bare-metal x86_64 (Debian 13 native on an ASUS Vivobook).
>
> To stress-test the kernel stability under load, I ran some heavy workloads:
> - A standalone loopback mount of GFS2 (using lock_nolock) with I/O stress
>   tests (100+ concurrent files).
> - A full multi-threaded compilation of the PCSX2 emulator (using CMake
>   and Ninja) with all CPU cores sustained at 100% load.
>
> The system behaved completely stable with no deadlocks, hangs, or OOM.
>
> Tested-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
>
> Best regards,
> Adrian

Andreas

> El vie, 24 jul 2026, 17:33, Andreas Gruenbacher <agruenba@redhat.com> escribió:
>>
>> On Tue, Jun 30, 2026 at 12:03 PM Adrian Garcia Casado
>> <adriangarciacasado42@gmail.com> wrote:
>> > In gfs2_inode_lookup() and other parts of the GFS2 filesystem,
>> > ip->i_gl is accessed and dereferenced via RCU helpers like
>> > rcu_dereference_check() and rcu_access_pointer(). However, the
>> > actual i_gl pointer in struct gfs2_inode was never annotated
>> > with __rcu in incore.h.
>> >
>> > This missing annotation causes Sparse to throw multiple
>> > "incompatible types in comparison expression (different address spaces)"
>> > warnings and compilation-blocking errors under strict static analysis builds.
>>
>> Indeed, there are two sparse errors related to i_gl.
>>
>> > Fix this by adding the __rcu annotation to i_gl in struct gfs2_inode.
>>
>> With this fix, I get about 200 sparse warnings instead of the two
>> errors. So thanks for pointing out that there are errors, but without
>> fixing any of the underlying problems, this patch isn't very useful.
>>
>> Andreas
>>
>> > Signed-off-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
>> > Tested-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
>> > ---
>> >
>> > diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
>> > index 6146577..16df753 100644
>> > --- a/fs/gfs2/incore.h
>> > +++ b/fs/gfs2/incore.h
>> > @@ -392,7 +392,7 @@ struct gfs2_inode {
>> >         u64 i_generation;
>> >         u64 i_eattr;
>> >         unsigned long i_flags;          /* GIF_... */
>> > -       struct gfs2_glock *i_gl;
>> > +       struct gfs2_glock __rcu *i_gl;
>> >         struct gfs2_holder i_iopen_gh;
>> >         struct gfs2_qadata *i_qadata; /* quota allocation data */
>> >         struct gfs2_holder i_rgd_gh;
>>
>> Applied, thanks.
>>
>>
>>
>> Andreas
>>

[PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian Garcia Casado]

In gfs2_inode_lookup() and other parts of the GFS2 filesystem,
ip->i_gl is accessed and dereferenced via RCU helpers like
rcu_dereference_check() and rcu_access_pointer(). However, the
actual i_gl pointer in struct gfs2_inode was never annotated
with __rcu in incore.h.

This missing annotation causes Sparse to throw multiple
"incompatible types in comparison expression (different address spaces)"
warnings and compilation-blocking errors under strict static analysis builds.

Fix this by adding the __rcu annotation to i_gl in struct gfs2_inode.

Signed-off-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
Tested-by: Adrian Garcia Casado <adriangarciacasado42@gmail.com>
---

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 6146577..16df753 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -392,7 +392,7 @@ struct gfs2_inode {
 	u64 i_generation;
 	u64 i_eattr;
 	unsigned long i_flags;		/* GIF_... */
-	struct gfs2_glock *i_gl;
+	struct gfs2_glock __rcu *i_gl;
 	struct gfs2_holder i_iopen_gh;
 	struct gfs2_qadata *i_qadata; /* quota allocation data */
 	struct gfs2_holder i_rgd_gh;

[PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian]

Signed-off-by: Adrian <adrian@tu-correo.com>
---
 fs/gfs2/incore.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 614657778..16df75336 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -392,7 +392,7 @@ struct gfs2_inode {
 	u64 i_generation;
 	u64 i_eattr;
 	unsigned long i_flags;		/* GIF_... */
-	struct gfs2_glock *i_gl;
+	struct gfs2_glock __rcu *i_gl;
 	struct gfs2_holder i_iopen_gh;
 	struct gfs2_qadata *i_qadata; /* quota allocation data */
 	struct gfs2_holder i_rgd_gh;
-- 
2.47.3

[PATCH] gfs2: add missing __rcu annotation to i_gl in incore.h

[Adrian]

Signed-off-by: Adrian <adriangarciacasado42@gmail.com>
---
 fs/gfs2/incore.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 614657778..16df75336 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -392,7 +392,7 @@ struct gfs2_inode {
 	u64 i_generation;
 	u64 i_eattr;
 	unsigned long i_flags;		/* GIF_... */
-	struct gfs2_glock *i_gl;
+	struct gfs2_glock __rcu *i_gl;
 	struct gfs2_holder i_iopen_gh;
 	struct gfs2_qadata *i_qadata; /* quota allocation data */
 	struct gfs2_holder i_rgd_gh;
-- 
2.47.3