[PATCH v3 0/4] fs/9p: fix mmap regression

[PATCH v3 0/4] fs/9p: fix mmap regression

[Eric Van Hensbergen]

This series attempts to fix a reported exception with mmap
on newer kernels. 

Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
Reported-by: Robert Schwebel <r.schwebel@pengutronix.de>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
---
Changes in v3:
- Clarify debug print to read-only mmap mode versus no mmap mode in
  v9fs_file_mmap
- Fix suggested regression tags and propagate across series
- Link to v2: https://lore.kernel.org/r/20230716-fixes-overly-restrictive-mmap-v2-0-147d6b93f699@kernel.org

Changes in v2:
- fix requested changes in commit messages
- add patch to remove unnecessary invalidate_inode_pages in mmap readonly path
- Link to v1: https://lore.kernel.org/r/20230716-fixes-overly-restrictive-mmap-v1-0-0683b283b932@kernel.org

---
Eric Van Hensbergen (4):
      fs/9p: remove unnecessary and overrestrictive check
      fs/9p: fix typo in comparison logic for cache mode
      fs/9p: fix type mismatch in file cache mode helper
      fs/9p: remove unnecessary invalidate_inode_pages2

 fs/9p/fid.h      | 6 +++---
 fs/9p/vfs_file.c | 5 +----
 2 files changed, 4 insertions(+), 7 deletions(-)
---
base-commit: 95f41d87810083d8b3dedcce46a4e356cf4a9673
change-id: 20230716-fixes-overly-restrictive-mmap-30a23501e787

Best regards,
-- 
Eric Van Hensbergen <ericvh@kernel.org>

[PATCH v3 1/4] fs/9p: remove unnecessary and overrestrictive check

[Eric Van Hensbergen]

This eliminates a check for shared that was overrestrictive and
duplicated a check in generic_file_readonly_mmap.

Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
---
 fs/9p/vfs_file.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 2996fb00387f..9b61b480a9b0 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -505,9 +505,7 @@ v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
 	p9_debug(P9_DEBUG_MMAP, "filp :%p\n", filp);
 
 	if (!(v9ses->cache & CACHE_WRITEBACK)) {
-		p9_debug(P9_DEBUG_CACHE, "(no mmap mode)");
-		if (vma->vm_flags & VM_MAYSHARE)
-			return -ENODEV;
+		p9_debug(P9_DEBUG_CACHE, "(read-only mmap mode)");
 		invalidate_inode_pages2(filp->f_mapping);
 		return generic_file_readonly_mmap(filp, vma);
 	}

-- 
2.39.2

Re: [PATCH v3 1/4] fs/9p: remove unnecessary and overrestrictive check

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

Rule: 'Cc: stable@vger.kernel.org' or 'commit <sha1> upstream.'
Subject: [PATCH v3 1/4] fs/9p: remove unnecessary and overrestrictive check
Link: https://lore.kernel.org/stable/20230716-fixes-overly-restrictive-mmap-v3-1-769791f474fd%40kernel.org

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v3 1/4] fs/9p: remove unnecessary and overrestrictive check

[Greg KH]

On Wed, Jul 19, 2023 at 03:17:05PM +0000, Eric Van Hensbergen wrote:
> This eliminates a check for shared that was overrestrictive and
> duplicated a check in generic_file_readonly_mmap.
> 
> Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
> Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
> ---
>  fs/9p/vfs_file.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

[PATCH v3 2/4] fs/9p: fix typo in comparison logic for cache mode

[Eric Van Hensbergen]

There appears to be a typo in the comparison statement for the logic
which sets a file's cache mode based on mount flags.

Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
---
 fs/9p/fid.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/9p/fid.h b/fs/9p/fid.h
index 0c51889a60b3..297c2c377e3d 100644
--- a/fs/9p/fid.h
+++ b/fs/9p/fid.h
@@ -57,7 +57,7 @@ static inline void v9fs_fid_add_modes(struct p9_fid *fid, int s_flags,
 	   (s_flags & V9FS_DIRECT_IO) || (f_flags & O_DIRECT)) {
 		fid->mode |= P9L_DIRECT; /* no read or write cache */
 	} else if ((!(s_cache & CACHE_WRITEBACK)) ||
-				(f_flags & O_DSYNC) | (s_flags & V9FS_SYNC)) {
+				(f_flags & O_DSYNC) || (s_flags & V9FS_SYNC)) {
 		fid->mode |= P9L_NOWRITECACHE;
 	}
 }

-- 
2.39.2

Re: [PATCH v3 2/4] fs/9p: fix typo in comparison logic for cache mode

[Greg KH]

On Wed, Jul 19, 2023 at 03:17:06PM +0000, Eric Van Hensbergen wrote:
> There appears to be a typo in the comparison statement for the logic
> which sets a file's cache mode based on mount flags.
> 
> Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
> Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
> ---
>  fs/9p/fid.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

[PATCH v3 3/4] fs/9p: fix type mismatch in file cache mode helper

[Eric Van Hensbergen]

There were two flags (s_flags and s_cache) which had incorrect signed
type in the parameters of the file cache mode helper function.

Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
---
 fs/9p/fid.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/9p/fid.h b/fs/9p/fid.h
index 297c2c377e3d..29281b7c3887 100644
--- a/fs/9p/fid.h
+++ b/fs/9p/fid.h
@@ -46,8 +46,8 @@ static inline struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
  * NOTE: these are set after open so only reflect 9p client not
  * underlying file system on server.
  */
-static inline void v9fs_fid_add_modes(struct p9_fid *fid, int s_flags,
-	int s_cache, unsigned int f_flags)
+static inline void v9fs_fid_add_modes(struct p9_fid *fid, unsigned int s_flags,
+	unsigned int s_cache, unsigned int f_flags)
 {
 	if (fid->qid.type != P9_QTFILE)
 		return;

-- 
2.39.2

Re: [PATCH v3 3/4] fs/9p: fix type mismatch in file cache mode helper

[Greg KH]

On Wed, Jul 19, 2023 at 03:17:07PM +0000, Eric Van Hensbergen wrote:
> There were two flags (s_flags and s_cache) which had incorrect signed
> type in the parameters of the file cache mode helper function.
> 
> Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
> Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
> ---
>  fs/9p/fid.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)


<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

[PATCH v3 4/4] fs/9p: remove unnecessary invalidate_inode_pages2

[Eric Van Hensbergen]

There was an invalidate_inode_pages2
added to mmap that is unnecessary.

Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
---
 fs/9p/vfs_file.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 9b61b480a9b0..11cd8d23f6f2 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -506,7 +506,6 @@ v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
 
 	if (!(v9ses->cache & CACHE_WRITEBACK)) {
 		p9_debug(P9_DEBUG_CACHE, "(read-only mmap mode)");
-		invalidate_inode_pages2(filp->f_mapping);
 		return generic_file_readonly_mmap(filp, vma);
 	}
 

-- 
2.39.2

Re: [PATCH v3 4/4] fs/9p: remove unnecessary invalidate_inode_pages2

[Greg KH]

On Wed, Jul 19, 2023 at 03:17:08PM +0000, Eric Van Hensbergen wrote:
> There was an invalidate_inode_pages2
> added to mmap that is unnecessary.
> 
> Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
> Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
> ---
>  fs/9p/vfs_file.c | 1 -
>  1 file changed, 1 deletion(-)


<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

Re: [PATCH v3 0/4] fs/9p: fix mmap regression

[Robert Schwebel]

Hi Eric,

On Wed, Jul 19, 2023 at 03:17:04PM +0000, Eric Van Hensbergen wrote:
> This series attempts to fix a reported exception with mmap
> on newer kernels.
>
> Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
> Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
> Reported-by: Robert Schwebel <r.schwebel@pengutronix.de>
> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
> ---
> Changes in v3:
> - Clarify debug print to read-only mmap mode versus no mmap mode in
>   v9fs_file_mmap
> - Fix suggested regression tags and propagate across series
> - Link to v2: https://lore.kernel.org/r/20230716-fixes-overly-restrictive-mmap-v2-0-147d6b93f699@kernel.org
>
> Changes in v2:
> - fix requested changes in commit messages
> - add patch to remove unnecessary invalidate_inode_pages in mmap readonly path
> - Link to v1: https://lore.kernel.org/r/20230716-fixes-overly-restrictive-mmap-v1-0-0683b283b932@kernel.org

I've tested this patch series with my qemu setup and it resolves the
issue. Thanks for taking care!

Tested-by: Robert Schwebel <r.schwebel@pengutronix.de>

----------8<----------

rsc@dude05:~/work/DistroKit$ configs/platform-v7a/run
Forwarding SSH port 127.0.0.1:24910 -> qemu:22
[    0.000000] L2C: platform modifies aux control register: 0x02020000 -> 0x02420000
[    0.000000] L2C: DT/platform modifies aux control register: 0x02020000 -> 0x02420000
[    0.004896] smp_twd: clock not found -2
[    0.726397] simple-pm-bus bus@40000000:motherboard-bus@40000000:iofpga@7,00000000: Failed to create device link (0x180) with dcc:tcrefclk
[    0.742338] simple-pm-bus bus@40000000:motherboard-bus@40000000:iofpga@7,00000000: Failed to create device link (0x180) with dcc:tcrefclk
[    0.809910] physmap-flash 48000000.psram: map_probe failed
[    1.201306] 9pnet_virtio: no channels available for device root

 ____                        _                   _
|  _ \ ___ _ __   __ _ _   _| |_ _ __ ___  _ __ (_)_  __
| |_) / _ \ '_ \ / _` | | | | __| '__/ _ \| '_ \| \ \/ /
|  __/  __/ | | | (_| | |_| | |_| | | (_) | | | | |>  <
|_|   \___|_| |_|\__, |\__,_|\__|_|  \___/|_| |_|_/_/\_\
                 |___/

 ____  _     _             _  ___ _
|  _ \(_)___| |_ _ __ ___ | |/ (_) |_
| | | | / __| __| '__/ _ \| ' /| | __|
| |_| | \__ \ |_| | | (_) | . \| | |_
|____/|_|___/\__|_|  \___/|_|\_\_|\__|


OSELAS(R)-DistroKit-2019.12.0-00429-g57ffae760eb9 / v7a-2019.12.0-00429-g57ffae760eb9
ptxdist-2023.07.1/2023-07-11T19:56:50+0200

DistroKit login: root
root@DistroKit:~ mount / -o remount,rw
root@DistroKit:~ ldconfig
root@DistroKit:~ uname -a
Linux DistroKit 6.4.0 #1 SMP PREEMPT 2023-07-01T00:00:00+00:00 armv7l GNU/Linux

----------8<----------

rsc
-- 
Pengutronix e.K.                           | Dipl.-Ing. Robert Schwebel  |
Steuerwalder Str. 21                       | https://www.pengutronix.de/ |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-9    |

Re: [PATCH v3 0/4] fs/9p: fix mmap regression

[Eric Van Hensbergen]

Awesome, thanks for verifying Robert.  Will send a pull request for
this in a few days.

      -eric

On Mon, Jul 24, 2023 at 4:17 PM Robert Schwebel
<r.schwebel@pengutronix.de> wrote:
>
> Hi Eric,
>
> On Wed, Jul 19, 2023 at 03:17:04PM +0000, Eric Van Hensbergen wrote:
> > This series attempts to fix a reported exception with mmap
> > on newer kernels.
> >
> > Fixes: 1543b4c5071c ("fs/9p: remove writeback fid and fix per-file modes")
> > Link: https://lore.kernel.org/v9fs/ZK25XZ%2BGpR3KHIB%2F@pengutronix.de/
> > Reported-by: Robert Schwebel <r.schwebel@pengutronix.de>
> > Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
> > ---
> > Changes in v3:
> > - Clarify debug print to read-only mmap mode versus no mmap mode in
> >   v9fs_file_mmap
> > - Fix suggested regression tags and propagate across series
> > - Link to v2: https://lore.kernel.org/r/20230716-fixes-overly-restrictive-mmap-v2-0-147d6b93f699@kernel.org
> >
> > Changes in v2:
> > - fix requested changes in commit messages
> > - add patch to remove unnecessary invalidate_inode_pages in mmap readonly path
> > - Link to v1: https://lore.kernel.org/r/20230716-fixes-overly-restrictive-mmap-v1-0-0683b283b932@kernel.org
>
> I've tested this patch series with my qemu setup and it resolves the
> issue. Thanks for taking care!
>
> Tested-by: Robert Schwebel <r.schwebel@pengutronix.de>
>
> ----------8<----------
>
> rsc@dude05:~/work/DistroKit$ configs/platform-v7a/run
> Forwarding SSH port 127.0.0.1:24910 -> qemu:22
> [    0.000000] L2C: platform modifies aux control register: 0x02020000 -> 0x02420000
> [    0.000000] L2C: DT/platform modifies aux control register: 0x02020000 -> 0x02420000
> [    0.004896] smp_twd: clock not found -2
> [    0.726397] simple-pm-bus bus@40000000:motherboard-bus@40000000:iofpga@7,00000000: Failed to create device link (0x180) with dcc:tcrefclk
> [    0.742338] simple-pm-bus bus@40000000:motherboard-bus@40000000:iofpga@7,00000000: Failed to create device link (0x180) with dcc:tcrefclk
> [    0.809910] physmap-flash 48000000.psram: map_probe failed
> [    1.201306] 9pnet_virtio: no channels available for device root
>
>  ____                        _                   _
> |  _ \ ___ _ __   __ _ _   _| |_ _ __ ___  _ __ (_)_  __
> | |_) / _ \ '_ \ / _` | | | | __| '__/ _ \| '_ \| \ \/ /
> |  __/  __/ | | | (_| | |_| | |_| | | (_) | | | | |>  <
> |_|   \___|_| |_|\__, |\__,_|\__|_|  \___/|_| |_|_/_/\_\
>                  |___/
>
>  ____  _     _             _  ___ _
> |  _ \(_)___| |_ _ __ ___ | |/ (_) |_
> | | | | / __| __| '__/ _ \| ' /| | __|
> | |_| | \__ \ |_| | | (_) | . \| | |_
> |____/|_|___/\__|_|  \___/|_|\_\_|\__|
>
>
> OSELAS(R)-DistroKit-2019.12.0-00429-g57ffae760eb9 / v7a-2019.12.0-00429-g57ffae760eb9
> ptxdist-2023.07.1/2023-07-11T19:56:50+0200
>
> DistroKit login: root
> root@DistroKit:~ mount / -o remount,rw
> root@DistroKit:~ ldconfig
> root@DistroKit:~ uname -a
> Linux DistroKit 6.4.0 #1 SMP PREEMPT 2023-07-01T00:00:00+00:00 armv7l GNU/Linux
>
> ----------8<----------
>
> rsc
> --
> Pengutronix e.K.                           | Dipl.-Ing. Robert Schwebel  |
> Steuerwalder Str. 21                       | https://www.pengutronix.de/ |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-9    |
>