[PATCH] minix: fix bug when opening a file with O_DIRECT will

[PATCH] minix: fix bug when opening a file with O_DIRECT will

[Qinghua Jin]

Testcase:
1. create a minix file system and mount it
2. open a file on the file system with O_RDWR|O_CREAT|O_TRUNC|O_DIRECT
3. open fails with -EINVAL but leaves an empty file behind. All other
open() failures don't leave the failed open files behind.

It is hard to check the direct_IO op before creating the inode. Just as
ext4 and btrfs do, this patch will resolve the issue by allowing to 
create the file with O_DIRECT but returning error when writing the file.

Signed-off-by: Qinghua Jin <qhjin.dev@gmail.com>
---
 fs/minix/inode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index a71f1cf894b9..d4bd94234ef7 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -447,7 +447,8 @@ static const struct address_space_operations minix_aops = {
 	.writepage = minix_writepage,
 	.write_begin = minix_write_begin,
 	.write_end = generic_write_end,
-	.bmap = minix_bmap
+	.bmap = minix_bmap,
+	.direct_IO = noop_direct_IO
 };
 
 static const struct inode_operations minix_symlink_inode_operations = {
-- 
2.30.2

Re: [PATCH] minix: fix bug when opening a file with O_DIRECT will

[Jan Kara]

On Thu 06-01-22 11:30:41, Qinghua Jin wrote:
> Testcase:
> 1. create a minix file system and mount it
> 2. open a file on the file system with O_RDWR|O_CREAT|O_TRUNC|O_DIRECT
> 3. open fails with -EINVAL but leaves an empty file behind. All other
> open() failures don't leave the failed open files behind.
> 
> It is hard to check the direct_IO op before creating the inode. Just as
> ext4 and btrfs do, this patch will resolve the issue by allowing to 
> create the file with O_DIRECT but returning error when writing the file.
> 
> Signed-off-by: Qinghua Jin <qhjin.dev@gmail.com>

The patch looks good. Thanks. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Just out of curiosity: Do you happen to really use minix filesystem or was
this just a fallout from some fuzz testing or something like that?

								Honza
> ---
>  fs/minix/inode.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/minix/inode.c b/fs/minix/inode.c
> index a71f1cf894b9..d4bd94234ef7 100644
> --- a/fs/minix/inode.c
> +++ b/fs/minix/inode.c
> @@ -447,7 +447,8 @@ static const struct address_space_operations minix_aops = {
>  	.writepage = minix_writepage,
>  	.write_begin = minix_write_begin,
>  	.write_end = generic_write_end,
> -	.bmap = minix_bmap
> +	.bmap = minix_bmap,
> +	.direct_IO = noop_direct_IO
>  };
>  
>  static const struct inode_operations minix_symlink_inode_operations = {
> -- 
> 2.30.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH] minix: fix bug when opening a file with O_DIRECT will

[Christian Brauner]

On Fri, Jan 07, 2022 at 07:12:39AM +0800, Qinghua Jin wrote:
> On Thu, Jan 6, 2022 at 11:43 PM Jan Kara <jack@suse.cz> wrote:
> 
> > On Thu 06-01-22 11:30:41, Qinghua Jin wrote:
> > > Testcase:
> > > 1. create a minix file system and mount it
> > > 2. open a file on the file system with O_RDWR|O_CREAT|O_TRUNC|O_DIRECT
> > > 3. open fails with -EINVAL but leaves an empty file behind. All other
> > > open() failures don't leave the failed open files behind.
> > >
> > > It is hard to check the direct_IO op before creating the inode. Just as
> > > ext4 and btrfs do, this patch will resolve the issue by allowing to
> > > create the file with O_DIRECT but returning error when writing the file.
> > >
> > > Signed-off-by: Qinghua Jin <qhjin.dev@gmail.com>
> >
> > The patch looks good. Thanks. Feel free to add:
> >
> > Reviewed-by: Jan Kara <jack@suse.cz>
> >
> > Just out of curiosity: Do you happen to really use minix filesystem or was
> > this just a fallout from some fuzz testing or something like that?
> >
> > Thanks, It's a bug reported by colin.king@canonical.com
> https://bugzilla.kernel.org/show_bug.cgi?id=213041
> I don't include the email because it's not reachable.

Fwiw, Colin's now at Intel:
Colin Ian King <colin.king@intel.com>

(While I'm here:
 Acked-by: Christian Brauner <christian.brauner@ubuntu.com>)

[PATCH v2] minix: fix bug when opening a file with O_DIRECT

[Qinghua Jin]

Testcase:
1. create a minix file system and mount it
2. open a file on the file system with O_RDWR|O_CREAT|O_TRUNC|O_DIRECT
3. open fails with -EINVAL but leaves an empty file behind. All other
open() failures don't leave the failed open files behind.

It is hard to check the direct_IO op before creating the inode. Just as
ext4 and btrfs do, this patch will resolve the issue by allowing to
create the file with O_DIRECT but returning error when writing the file.

Reported-by: Colin Ian King <colin.king@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Qinghua Jin <qhjin.dev@gmail.com>
---
 fs/minix/inode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index a71f1cf894b9..d4bd94234ef7 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -447,7 +447,8 @@ static const struct address_space_operations minix_aops = {
 	.writepage = minix_writepage,
 	.write_begin = minix_write_begin,
 	.write_end = generic_write_end,
-	.bmap = minix_bmap
+	.bmap = minix_bmap,
+	.direct_IO = noop_direct_IO
 };
 
 static const struct inode_operations minix_symlink_inode_operations = {
-- 
2.30.2