[PATCH] xfs: remove unneeded ASSERT from xfs_itruncate_extents

[PATCH] xfs: remove unneeded ASSERT from xfs_itruncate_extents

[Carlos Maiolino]

There is no reason to ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); twice, so,
remove one of these ASSERT calls

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
 fs/xfs/xfs_inode.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 66282dc..25226ea 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1396,8 +1396,7 @@ xfs_itruncate_extents(
 	int			done = 0;
 
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
-	ASSERT(!atomic_read(&VFS_I(ip)->i_count) ||
-	       xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	ASSERT(!atomic_read(&VFS_I(ip)->i_count));
 	ASSERT(new_size <= XFS_ISIZE(ip));
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 	ASSERT(ip->i_itemp != NULL);
-- 
1.8.1

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Re: [PATCH] xfs: remove unneeded ASSERT from xfs_itruncate_extents

[Mark Tinguely]

On 01/28/13 08:04, Carlos Maiolino wrote:
> There is no reason to ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); twice, so,
> remove one of these ASSERT calls
>
> Signed-off-by: Carlos Maiolino<cmaiolino@redhat.com>
> ---
>   fs/xfs/xfs_inode.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 66282dc..25226ea 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1396,8 +1396,7 @@ xfs_itruncate_extents(
>   	int			done = 0;
>
>   	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
> -	ASSERT(!atomic_read(&VFS_I(ip)->i_count) ||
> -	       xfs_isilocked(ip, XFS_IOLOCK_EXCL));
> +	ASSERT(!atomic_read(&VFS_I(ip)->i_count));
>   	ASSERT(new_size<= XFS_ISIZE(ip));
>   	ASSERT(tp->t_flags&  XFS_TRANS_PERM_LOG_RES);
>   	ASSERT(ip->i_itemp != NULL);

You removed an XFS_IOLOCK_EXCL assert not a duplicate
XFS_ILOCK_EXCL assert. It maybe more obvious if the
first assert read:

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL) ||
	       xfs_isilocked(ip, XFS_IOLOCK_EXCL));
	ASSERT(!atomic_read(&VFS_I(ip)->i_count));
...

--Mark Tinguely.

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Re: [PATCH] xfs: remove unneeded ASSERT from xfs_itruncate_extents

[Carlos Maiolino]

Meh, you're right, cheated by my eyes.

but the suggestion looks nice to avoid another ones to fall in the same mistake,
will send a change to it, thanks Mark


On Mon, Jan 28, 2013 at 08:14:12AM -0600, Mark Tinguely wrote:
> On 01/28/13 08:04, Carlos Maiolino wrote:
> >There is no reason to ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); twice, so,
> >remove one of these ASSERT calls
> >
> >Signed-off-by: Carlos Maiolino<cmaiolino@redhat.com>
> >---
> >  fs/xfs/xfs_inode.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> >diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> >index 66282dc..25226ea 100644
> >--- a/fs/xfs/xfs_inode.c
> >+++ b/fs/xfs/xfs_inode.c
> >@@ -1396,8 +1396,7 @@ xfs_itruncate_extents(
> >  	int			done = 0;
> >
> >  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
> >-	ASSERT(!atomic_read(&VFS_I(ip)->i_count) ||
> >-	       xfs_isilocked(ip, XFS_IOLOCK_EXCL));
> >+	ASSERT(!atomic_read(&VFS_I(ip)->i_count));
> >  	ASSERT(new_size<= XFS_ISIZE(ip));
> >  	ASSERT(tp->t_flags&  XFS_TRANS_PERM_LOG_RES);
> >  	ASSERT(ip->i_itemp != NULL);
> 
> You removed an XFS_IOLOCK_EXCL assert not a duplicate
> XFS_ILOCK_EXCL assert. It maybe more obvious if the
> first assert read:
> 
> 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL) ||
> 	       xfs_isilocked(ip, XFS_IOLOCK_EXCL));
> 	ASSERT(!atomic_read(&VFS_I(ip)->i_count));
> ...
> 
> --Mark Tinguely.

-- 
Carlos

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Re: [PATCH] xfs: remove unneeded ASSERT from xfs_itruncate_extents

[Dave Chinner]

On Mon, Jan 28, 2013 at 09:04:30AM -0500, Carlos Maiolino wrote:
> There is no reason to ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); twice, so,
> remove one of these ASSERT calls

Second assert is for the IOLOCK, not the ILOCK....

> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> ---
>  fs/xfs/xfs_inode.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 66282dc..25226ea 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1396,8 +1396,7 @@ xfs_itruncate_extents(
>  	int			done = 0;
>  
>  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
> -	ASSERT(!atomic_read(&VFS_I(ip)->i_count) ||
> -	       xfs_isilocked(ip, XFS_IOLOCK_EXCL));
> +	ASSERT(!atomic_read(&VFS_I(ip)->i_count));

The code is correct. The ASSERT is testing the locking constraints on
the XFS_IOLOCK_EXCL. That is, if xfs_itruncate_extents() is called
in the VFS inode reclaim path (i.e. via xfs_inactive()), the IO lock
is not used (throws lockdep warnings). Hence the ASSERT is checking
that if we hold an inode reference, we are also holding the IO lock.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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