linux-kernel - Re: [PATCH v2] xfs: Check for deallayed allocations before setting extsize

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Message-ID: <ZwjnKi+ZyvrLcOiF@li-bb2b2a4c-3307-11b2-a85c-8fa5c3a69313.ibm.com>
Date: Fri, 11 Oct 2024 14:21:54 +0530
From: Ojaswin Mujoo <ojaswin@...ux.ibm.com>
To: "Darrick J. Wong" <djwong@...nel.org>
Cc: linux-xfs@...r.kernel.org, Ritesh Harjani <ritesh.list@...il.com>,
        linux-kernel@...r.kernel.org, dchinner@...hat.com,
        Chandan Babu R <chandan.babu@...cle.com>,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH v2] xfs: Check for deallayed allocations before setting
 extsize

On Thu, Oct 10, 2024 at 11:34:47AM -0700, Darrick J. Wong wrote:
> On Thu, Oct 10, 2024 at 12:06:17PM +0530, Ojaswin Mujoo wrote:
> > Extsize is allowed to be set on files with no data in it. For this,
> > we were checking if the files have extents but missed to check if
> > delayed extents were present. This patch adds that check.
> > 
> > While we are at it, also refactor this check into a helper since
> > its used in some other places as well like xfs_inactive() or
> > xfs_ioctl_setattr_xflags()
> > 
> > **Without the patch (SUCCEEDS)**
> > 
> > $ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536'
> > 
> > wrote 1024/1024 bytes at offset 0
> > 1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec)
> > 
> > **With the patch (FAILS as expected)**
> > 
> > $ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536'
> > 
> > wrote 1024/1024 bytes at offset 0
> > 1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec)
> > xfs_io: FS_IOC_FSSETXATTR testfile: Invalid argument
> > 
> > Reviewed-by: Christoph Hellwig <hch@....de>
> > Signed-off-by: Ojaswin Mujoo <ojaswin@...ux.ibm.com>
> > ---
> > 
> > * Changes since v1 *
> > 
> >  - RVB by Christoph
> >  - Added a helper to check if inode has data instead of
> >    open coding.
> > 	
> > v1:
> > https://lore.kernel.org/linux-xfs/Zv_cTc6cgxszKGy3@infradead.org/T/#mf949dafb2b2f63bea1f7c0ce5265a2527aaf22a9
> > 
> >  fs/xfs/xfs_inode.c | 2 +-
> >  fs/xfs/xfs_inode.h | 5 +++++
> >  fs/xfs/xfs_ioctl.c | 5 +++--
> >  3 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> > index bcc277fc0a83..3d083a8fd8ed 100644
> > --- a/fs/xfs/xfs_inode.c
> > +++ b/fs/xfs/xfs_inode.c
> > @@ -1409,7 +1409,7 @@ xfs_inactive(
> >  
> >  	if (S_ISREG(VFS_I(ip)->i_mode) &&
> >  	    (ip->i_disk_size != 0 || XFS_ISIZE(ip) != 0 ||
> > -	     ip->i_df.if_nextents > 0 || ip->i_delayed_blks > 0))
> > +	     xfs_inode_has_data(ip)))
> >  		truncate = 1;
> >  
> >  	if (xfs_iflags_test(ip, XFS_IQUOTAUNCHECKED)) {
> > diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> > index 97ed912306fd..ae1ccf2a3c8b 100644
> > --- a/fs/xfs/xfs_inode.h
> > +++ b/fs/xfs/xfs_inode.h
> > @@ -292,6 +292,11 @@ static inline bool xfs_is_cow_inode(struct xfs_inode *ip)
> >  	return xfs_is_reflink_inode(ip) || xfs_is_always_cow_inode(ip);
> >  }
> >  
> > +static inline bool xfs_inode_has_data(struct xfs_inode *ip)
> 
> Can you please change this to "const struct xfs_inode *ip"?
> This predicate function doesn't change @ip.

> 
> I might've called it xfs_inode_has_filedata fwiw, but the current name
> is fine with me.

Hey Darrick, sure I'll make it const and change data -> filedata.

Thanks for the review,
ojaswin

> 
> --D
> 
> > +{
> > +	return (ip->i_df.if_nextents > 0 || ip->i_delayed_blks > 0);
> > +}
> > +
> >  /*
> >   * Check if an inode has any data in the COW fork.  This might be often false
> >   * even for inodes with the reflink flag when there is no pending COW operation.
> > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> > index a20d426ef021..88b9c8cf0272 100644
> > --- a/fs/xfs/xfs_ioctl.c
> > +++ b/fs/xfs/xfs_ioctl.c
> > @@ -481,7 +481,7 @@ xfs_ioctl_setattr_xflags(
> >  
> >  	if (rtflag != XFS_IS_REALTIME_INODE(ip)) {
> >  		/* Can't change realtime flag if any extents are allocated. */
> > -		if (ip->i_df.if_nextents || ip->i_delayed_blks)
> > +		if (xfs_inode_has_data(ip))
> >  			return -EINVAL;
> >  
> >  		/*
> > @@ -602,7 +602,8 @@ xfs_ioctl_setattr_check_extsize(
> >  	if (!fa->fsx_valid)
> >  		return 0;
> >  
> > -	if (S_ISREG(VFS_I(ip)->i_mode) && ip->i_df.if_nextents &&
> > +	if (S_ISREG(VFS_I(ip)->i_mode) &&
> > +	    xfs_inode_has_data(ip) &&
> >  	    XFS_FSB_TO_B(mp, ip->i_extsize) != fa->fsx_extsize)
> >  		return -EINVAL;
> >  
> > -- 
> > 2.43.5
> >