Re: [PATCH 06/12] xfs: remove XFS_TRANS_NOFS

Darrick J. Wong
2019-06-24T15:58:51Z

On Mon, Jun 24, 2019 at 07:52:47AM +0200, Christoph Hellwig wrote:
> Instead of a magic flag for xfs_trans_alloc, just ensure all callers
> that can't relclaim through the file system use memalloc_nofs_save to
> set the per-task nofs flag.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Hmm this finally fixes up the mess I left where COW fork cleanup
sometimes needs nofs and other times doesn't... :)

> ---
> fs/xfs/libxfs/xfs_shared.h | 1 -
> fs/xfs/xfs_aops.c | 12 +++++++++---
> fs/xfs/xfs_file.c | 12 +++++++++---
> fs/xfs/xfs_iomap.c | 2 +-
> fs/xfs/xfs_reflink.c | 4 ++--
> fs/xfs/xfs_trans.c | 4 +---
> 6 files changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
> index 4e909791aeac..1f2b5a0c71b4 100644
> --- a/fs/xfs/libxfs/xfs_shared.h
> +++ b/fs/xfs/libxfs/xfs_shared.h
> @@ -65,7 +65,6 @@ void xfs_log_get_max_trans_res(struct xfs_mount *mp,
> #define XFS_TRANS_DQ_DIRTY 0x10 /* at least one dquot in trx dirty */
> #define XFS_TRANS_RESERVE 0x20 /* OK to use reserved data blocks */
> #define XFS_TRANS_NO_WRITECOUNT 0x40 /* do not elevate SB writecount */
> -#define XFS_TRANS_NOFS 0x80 /* pass KM_NOFS to kmem_alloc */
> /*
> * LOWMODE is used by the allocator to activate the lowspace algorithm - when
> * free space is running low the extent allocator may choose to allocate an
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 93a760f13017..633baaaff7ae 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -138,8 +138,7 @@ xfs_setfilesize_trans_alloc(
> struct xfs_trans *tp;
> int error;
>
> - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0,
> - XFS_TRANS_NOFS, &tp);
> + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
> if (error)
> return error;
>
> @@ -236,6 +235,7 @@ STATIC void
> xfs_end_ioend(
> struct xfs_ioend *ioend)
> {
> + unsigned int nofs_flag = memalloc_nofs_save();
> struct list_head ioend_list;
> struct xfs_inode *ip = XFS_I(ioend->io_inode);
> xfs_off_t offset = ioend->io_offset;
> @@ -282,6 +282,8 @@ xfs_end_ioend(
> list_del_init(&ioend->io_list);
> xfs_destroy_ioend(ioend, error);
> }
> +
> + memalloc_nofs_restore(nofs_flag);
> }
>
> /*
> @@ -663,8 +665,12 @@ xfs_submit_ioend(
> (ioend->io_fork == XFS_COW_FORK ||
> ioend->io_type != IOMAP_UNWRITTEN) &&
> xfs_ioend_is_append(ioend) &&
> - !ioend->io_append_trans)
> + !ioend->io_append_trans) {
> + unsigned nofs_flag = memalloc_nofs_save();

unsigned int? Seeing as you use that everywhere else...

--D

> +
> status = xfs_setfilesize_trans_alloc(ioend);
> + memalloc_nofs_restore(nofs_flag);
> + }
>
> ioend->io_bio->bi_private = ioend;
> ioend->io_bio->bi_end_io = xfs_end_bio;
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 916a35cae5e9..f2d806ef8f06 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -379,6 +379,7 @@ xfs_dio_write_end_io(
> struct inode *inode = file_inode(iocb->ki_filp);
> struct xfs_inode *ip = XFS_I(inode);
> loff_t offset = iocb->ki_pos;
> + unsigned int nofs_flag;
> int error = 0;
>
> trace_xfs_end_io_direct_write(ip, offset, size);
> @@ -395,10 +396,11 @@ xfs_dio_write_end_io(
> */
> XFS_STATS_ADD(ip->i_mount, xs_write_bytes, size);
>
> + nofs_flag = memalloc_nofs_save();
> if (flags & IOMAP_DIO_COW) {
> error = xfs_reflink_end_cow(ip, offset, size);
> if (error)
> - return error;
> + goto out;
> }
>
> /*
> @@ -407,8 +409,10 @@ xfs_dio_write_end_io(
> * earlier allows a racing dio read to find unwritten extents before
> * they are converted.
> */
> - if (flags & IOMAP_DIO_UNWRITTEN)
> - return xfs_iomap_write_unwritten(ip, offset, size, true);
> + if (flags & IOMAP_DIO_UNWRITTEN) {
> + error = xfs_iomap_write_unwritten(ip, offset, size, true);
> + goto out;
> + }
>
> /*
> * We need to update the in-core inode size here so that we don't end up
> @@ -430,6 +434,8 @@ xfs_dio_write_end_io(
> spin_unlock(&ip->i_flags_lock);
> }
>
> +out:
> + memalloc_nofs_restore(nofs_flag);
> return error;
> }
>
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 6b29452bfba0..461ea023b910 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -782,7 +782,7 @@ xfs_iomap_write_unwritten(
> * complete here and might deadlock on the iolock.
> */
> error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
> - XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp);
> + XFS_TRANS_RESERVE, &tp);
> if (error)
> return error;
>
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index 680ae7662a78..0b23c2b29609 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -572,7 +572,7 @@ xfs_reflink_cancel_cow_range(
>
> /* Start a rolling transaction to remove the mappings */
> error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
> - 0, 0, XFS_TRANS_NOFS, &tp);
> + 0, 0, 0, &tp);
> if (error)
> goto out;
>
> @@ -631,7 +631,7 @@ xfs_reflink_end_cow_extent(
>
> resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
> error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
> - XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp);
> + XFS_TRANS_RESERVE, &tp);
> if (error)
> return error;
>
> diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
> index 0746b329a937..21228d7455af 100644
> --- a/fs/xfs/xfs_trans.c
> +++ b/fs/xfs/xfs_trans.c
> @@ -264,9 +264,7 @@ xfs_trans_alloc(
> * GFP_NOFS allocation context so that we avoid lockdep false positives
> * by doing GFP_KERNEL allocations inside sb_start_intwrite().
> */
> - tp = kmem_zone_zalloc(xfs_trans_zone,
> - (flags & XFS_TRANS_NOFS) ? KM_NOFS : KM_SLEEP);
> -
> + tp = kmem_zone_zalloc(xfs_trans_zone, KM_SLEEP);
> if (!(flags & XFS_TRANS_NO_WRITECOUNT))
> sb_start_intwrite(mp->m_super);
>
> --
> 2.20.1
>