Re: [PATCH 07/43] xfs: preserve RT reservations across remounts

Darrick J. Wong
2025-02-06T20:14:30Z

On Thu, Feb 06, 2025 at 07:44:23AM +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>

Looks fine,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
> fs/xfs/xfs_mount.c | 30 ++++++++++++++++++++++--------
> fs/xfs/xfs_mount.h | 3 ++-
> fs/xfs/xfs_super.c | 2 +-
> 3 files changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index b81a03b3133d..26793d4f2707 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -464,11 +464,21 @@ xfs_mount_reset_sbqflags(
> return xfs_sync_sb(mp, false);
> }
>
> +static const char *const xfs_free_pool_name[] = {
> + [XC_FREE_BLOCKS] = "free blocks",
> + [XC_FREE_RTEXTENTS] = "free rt extents",
> +};
> +
> 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
> @@ -681,6 +691,7 @@ xfs_mountfs(
> uint quotamount = 0;
> uint quotaflags = 0;
> int error = 0;
> + int i;
>
> xfs_sb_mount_common(mp, sbp);
>
> @@ -1049,18 +1060,21 @@ 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,
> - "Unable to allocate reserve blocks. Continuing without reserve pool.");
> + 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 for %s.",
> + xfs_free_pool_name[i]);
> + }
>
> /* 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 300ffefb2abd..2d0e34e517b1 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -647,7 +647,8 @@ 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 f0b0d8320c51..5c9a2a0826ff 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -947,7 +947,7 @@ 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
>
>