Re: [PATCH v2 01/15] xfs: pull up dfops from xfs_itruncate_extents()

[Bill O'Donnell <billodo@redhat.com>]

On Mon, Jul 23, 2018 at 09:04:00AM -0400, Brian Foster wrote:
> xfs_itruncate_extents[_flags]() uses a local dfops with a
> transaction provided by the caller. It uses hacky ->t_dfops
> replacement logic to avoid stomping over an already populated
> ->t_dfops.
> 
> The latter never occurs for current callers and the logic itself is
> not really appropriate. Clean this up by updating all callers to
> initialize a dfops and to use that down in xfs_itruncate_extents().
> This more closely resembles the upcoming logic where dfops will be
> embedded within the transaction. We can also replace the
> xfs_defer_init() in the xfs_itruncate_extents_flags() loop with an
> assert. Both dfops and firstblock should be in a valid state
> after xfs_defer_finish() and the inode joined to the dfops is fixed
> throughout the loop.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Looks good.
Reviewed-by: Bill O'Donnell <billodo@redhat.com>

> ---
>  fs/xfs/xfs_attr_inactive.c | 3 +++
>  fs/xfs/xfs_bmap_util.c     | 2 ++
>  fs/xfs/xfs_inode.c         | 8 +++-----
>  fs/xfs/xfs_iops.c          | 3 +++
>  fs/xfs/xfs_qm_syscalls.c   | 3 +++
>  5 files changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
> index 7ce10055f275..d3055972d3a6 100644
> --- a/fs/xfs/xfs_attr_inactive.c
> +++ b/fs/xfs/xfs_attr_inactive.c
> @@ -26,6 +26,7 @@
>  #include "xfs_quota.h"
>  #include "xfs_trace.h"
>  #include "xfs_dir2.h"
> +#include "xfs_defer.h"
>  
>  /*
>   * Look at all the extents for this logical region,
> @@ -381,6 +382,7 @@ xfs_attr_inactive(
>  {
>  	struct xfs_trans	*trans;
>  	struct xfs_mount	*mp;
> +	struct xfs_defer_ops	dfops;
>  	int			lock_mode = XFS_ILOCK_SHARED;
>  	int			error = 0;
>  
> @@ -397,6 +399,7 @@ xfs_attr_inactive(
>  	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_attrinval, 0, 0, 0, &trans);
>  	if (error)
>  		goto out_destroy_fork;
> +	xfs_defer_init(trans, &dfops);
>  
>  	lock_mode = XFS_ILOCK_EXCL;
>  	xfs_ilock(dp, lock_mode);
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index d3a314fd721f..ee9481b142f0 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -792,6 +792,7 @@ xfs_free_eofblocks(
>  	int			nimaps;
>  	struct xfs_bmbt_irec	imap;
>  	struct xfs_mount	*mp = ip->i_mount;
> +	struct xfs_defer_ops	dfops;
>  
>  	/*
>  	 * Figure out if there are any blocks beyond the end
> @@ -831,6 +832,7 @@ xfs_free_eofblocks(
>  			ASSERT(XFS_FORCED_SHUTDOWN(mp));
>  			return error;
>  		}
> +		xfs_defer_init(tp, &dfops);
>  
>  		xfs_ilock(ip, XFS_ILOCK_EXCL);
>  		xfs_trans_ijoin(tp, ip, 0);
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 7b2694d3901a..7d7d7e95fa17 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1541,8 +1541,6 @@ xfs_itruncate_extents_flags(
>  {
>  	struct xfs_mount	*mp = ip->i_mount;
>  	struct xfs_trans	*tp = *tpp;
> -	struct xfs_defer_ops	*odfops = tp->t_dfops;
> -	struct xfs_defer_ops	dfops;
>  	xfs_fileoff_t		first_unmap_block;
>  	xfs_fileoff_t		last_block;
>  	xfs_filblks_t		unmap_len;
> @@ -1579,7 +1577,7 @@ xfs_itruncate_extents_flags(
>  	ASSERT(first_unmap_block < last_block);
>  	unmap_len = last_block - first_unmap_block + 1;
>  	while (!done) {
> -		xfs_defer_init(tp, &dfops);
> +		ASSERT(tp->t_firstblock == NULLFSBLOCK);
>  		error = xfs_bunmapi(tp, ip, first_unmap_block, unmap_len, flags,
>  				    XFS_ITRUNC_MAX_EXTENTS, &done);
>  		if (error)
> @@ -1618,8 +1616,6 @@ xfs_itruncate_extents_flags(
>  	trace_xfs_itruncate_extents_end(ip, new_size);
>  
>  out:
> -	/* ->t_dfops points to local stack, don't leak it! */
> -	tp->t_dfops = odfops;
>  	*tpp = tp;
>  	return error;
>  out_bmap_cancel:
> @@ -1723,6 +1719,7 @@ xfs_inactive_truncate(
>  {
>  	struct xfs_mount	*mp = ip->i_mount;
>  	struct xfs_trans	*tp;
> +	struct xfs_defer_ops	dfops;
>  	int			error;
>  
>  	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
> @@ -1730,6 +1727,7 @@ xfs_inactive_truncate(
>  		ASSERT(XFS_FORCED_SHUTDOWN(mp));
>  		return error;
>  	}
> +	xfs_defer_init(tp, &dfops);
>  
>  	xfs_ilock(ip, XFS_ILOCK_EXCL);
>  	xfs_trans_ijoin(tp, ip, 0);
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 0fa29f39d658..704b57a8b99e 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -26,6 +26,7 @@
>  #include "xfs_dir2.h"
>  #include "xfs_trans_space.h"
>  #include "xfs_iomap.h"
> +#include "xfs_defer.h"
>  
>  #include <linux/capability.h>
>  #include <linux/xattr.h>
> @@ -812,6 +813,7 @@ xfs_setattr_size(
>  	struct inode		*inode = VFS_I(ip);
>  	xfs_off_t		oldsize, newsize;
>  	struct xfs_trans	*tp;
> +	struct xfs_defer_ops	dfops;
>  	int			error;
>  	uint			lock_flags = 0;
>  	bool			did_zeroing = false;
> @@ -915,6 +917,7 @@ xfs_setattr_size(
>  	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
>  	if (error)
>  		return error;
> +	xfs_defer_init(tp, &dfops);
>  
>  	lock_flags |= XFS_ILOCK_EXCL;
>  	xfs_ilock(ip, XFS_ILOCK_EXCL);
> diff --git a/fs/xfs/xfs_qm_syscalls.c b/fs/xfs/xfs_qm_syscalls.c
> index abc8a21e3a82..df0783303887 100644
> --- a/fs/xfs/xfs_qm_syscalls.c
> +++ b/fs/xfs/xfs_qm_syscalls.c
> @@ -22,6 +22,7 @@
>  #include "xfs_qm.h"
>  #include "xfs_trace.h"
>  #include "xfs_icache.h"
> +#include "xfs_defer.h"
>  
>  STATIC int	xfs_qm_log_quotaoff(xfs_mount_t *, xfs_qoff_logitem_t **, uint);
>  STATIC int	xfs_qm_log_quotaoff_end(xfs_mount_t *, xfs_qoff_logitem_t *,
> @@ -213,6 +214,7 @@ xfs_qm_scall_trunc_qfile(
>  {
>  	struct xfs_inode	*ip;
>  	struct xfs_trans	*tp;
> +	struct xfs_defer_ops	dfops;
>  	int			error;
>  
>  	if (ino == NULLFSINO)
> @@ -229,6 +231,7 @@ xfs_qm_scall_trunc_qfile(
>  		xfs_iunlock(ip, XFS_IOLOCK_EXCL);
>  		goto out_put;
>  	}
> +	xfs_defer_init(tp, &dfops);
>  
>  	xfs_ilock(ip, XFS_ILOCK_EXCL);
>  	xfs_trans_ijoin(tp, ip, 0);
> -- 
> 2.17.1
> 
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