Re: [PATCH 10/43] xfs: preserve RT reservations across remounts

Darrick J. Wong
2024-12-12T21:38:34Z

On Wed, Dec 11, 2024 at 09:54:35AM +0100, Christoph Hellwig wrote:
> From: Hans Holmberg <hans.holmberg@wdc.com>
>
> Introduce a reservation setting for rt devices so that zoned GC
> reservations are preserved over remount ro/rw cycles.
>
> Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/xfs_mount.c | 22 +++++++++++++++-------
> fs/xfs/xfs_mount.h | 3 ++-
> fs/xfs/xfs_super.c | 2 +-
> 3 files changed, 18 insertions(+), 9 deletions(-)
>
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index 4174035b2ac9..db910ecc1ed4 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -465,10 +465,15 @@ xfs_mount_reset_sbqflags(
> }
>
> uint64_t
> -xfs_default_resblks(xfs_mount_t *mp)
> +xfs_default_resblks(
> + struct xfs_mount *mp,
> + enum xfs_free_counter ctr)
> {
> uint64_t resblks;
>
> + if (ctr == XC_FREE_RTEXTENTS)
> + return 0;
> +
> /*
> * We default to 5% or 8192 fsbs of space reserved, whichever is
> * smaller. This is intended to cover concurrent allocation
> @@ -683,6 +688,7 @@ xfs_mountfs(
> uint quotamount = 0;
> uint quotaflags = 0;
> int error = 0;
> + int i;
>
> xfs_sb_mount_common(mp, sbp);
>
> @@ -1051,18 +1057,20 @@ xfs_mountfs(
> * privileged transactions. This is needed so that transaction
> * space required for critical operations can dip into this pool
> * when at ENOSPC. This is needed for operations like create with
> - * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
> - * are not allowed to use this reserved space.
> + * attr, unwritten extent conversion at ENOSPC, garbage collection
> + * etc. Data allocations are not allowed to use this reserved space.
> *
> * This may drive us straight to ENOSPC on mount, but that implies
> * we were already there on the last unmount. Warn if this occurs.
> */
> if (!xfs_is_readonly(mp)) {
> - error = xfs_reserve_blocks(mp, XC_FREE_BLOCKS,
> - xfs_default_resblks(mp));
> - if (error)
> - xfs_warn(mp,
> + for (i = 0; i < XC_FREE_NR; i++) {
> + error = xfs_reserve_blocks(mp, i,
> + xfs_default_resblks(mp, i));
> + if (error)
> + xfs_warn(mp,
> "Unable to allocate reserve blocks. Continuing without reserve pool.");

Should we be able to log *which* reserve block pool is out?

Otherwise looks good to me.

--D

> + }
>
> /* Reserve AG blocks for future btree expansion. */
> error = xfs_fs_reserve_ag_blocks(mp);
> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> index d92bce7bc184..73bc053fdd17 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -640,7 +640,8 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
> }
>
> extern void xfs_uuid_table_free(void);
> -extern uint64_t xfs_default_resblks(xfs_mount_t *mp);
> +uint64_t xfs_default_resblks(struct xfs_mount *mp,
> + enum xfs_free_counter ctr);
> extern int xfs_mountfs(xfs_mount_t *mp);
> extern void xfs_unmountfs(xfs_mount_t *);
>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 1960ee0aad45..f57c27940467 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -944,7 +944,7 @@ xfs_restore_resvblks(
> resblks = mp->m_resblks[i].save;
> mp->m_resblks[i].save = 0;
> } else
> - resblks = xfs_default_resblks(mp);
> + resblks = xfs_default_resblks(mp, i);
> xfs_reserve_blocks(mp, i, resblks);
> }
> }
> --
> 2.45.2
>
>