Re: [PATCH 11/13] xfs: rework splitting of indirect block reservations

Darrick J. Wong
2024-03-27T15:14:57Z

On Wed, Mar 27, 2024 at 12:03:16PM +0100, Christoph Hellwig wrote:
> Move the check if we have enough indirect blocks and the stealing of
> the deleted extent blocks out of xfs_bmap_split_indlen and into the
> caller to prepare for handling delayed allocation of RT extents that
> can't easily be stolen.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

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

--D

> ---
> fs/xfs/libxfs/xfs_bmap.c | 38 ++++++++++++++++----------------------
> 1 file changed, 16 insertions(+), 22 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 131d4f063b660a..9d0b7caa9a036c 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -4829,31 +4829,17 @@ xfs_bmapi_remap(
> * ores == 1). The number of stolen blocks is returned. The availability and
> * subsequent accounting of stolen blocks is the responsibility of the caller.
> */
> -static xfs_filblks_t
> +static void
> xfs_bmap_split_indlen(
> xfs_filblks_t ores, /* original res. */
> xfs_filblks_t *indlen1, /* ext1 worst indlen */
> - xfs_filblks_t *indlen2, /* ext2 worst indlen */
> - xfs_filblks_t avail) /* stealable blocks */
> + xfs_filblks_t *indlen2) /* ext2 worst indlen */
> {
> xfs_filblks_t len1 = *indlen1;
> xfs_filblks_t len2 = *indlen2;
> xfs_filblks_t nres = len1 + len2; /* new total res. */
> - xfs_filblks_t stolen = 0;
> xfs_filblks_t resfactor;
>
> - /*
> - * Steal as many blocks as we can to try and satisfy the worst case
> - * indlen for both new extents.
> - */
> - if (ores < nres && avail)
> - stolen = XFS_FILBLKS_MIN(nres - ores, avail);
> - ores += stolen;
> -
> - /* nothing else to do if we've satisfied the new reservation */
> - if (ores >= nres)
> - return stolen;
> -
> /*
> * We can't meet the total required reservation for the two extents.
> * Calculate the percent of the overall shortage between both extents
> @@ -4898,8 +4884,6 @@ xfs_bmap_split_indlen(
>
> *indlen1 = len1;
> *indlen2 = len2;
> -
> - return stolen;
> }
>
> int
> @@ -4915,7 +4899,7 @@ xfs_bmap_del_extent_delay(
> struct xfs_bmbt_irec new;
> int64_t da_old, da_new, da_diff = 0;
> xfs_fileoff_t del_endoff, got_endoff;
> - xfs_filblks_t got_indlen, new_indlen, stolen;
> + xfs_filblks_t got_indlen, new_indlen, stolen = 0;
> uint32_t state = xfs_bmap_fork_to_state(whichfork);
> uint64_t fdblocks;
> int error = 0;
> @@ -4994,8 +4978,19 @@ xfs_bmap_del_extent_delay(
> new_indlen = xfs_bmap_worst_indlen(ip, new.br_blockcount);
>
> WARN_ON_ONCE(!got_indlen || !new_indlen);
> - stolen = xfs_bmap_split_indlen(da_old, &got_indlen, &new_indlen,
> - del->br_blockcount);
> + /*
> + * Steal as many blocks as we can to try and satisfy the worst
> + * case indlen for both new extents.
> + */
> + da_new = got_indlen + new_indlen;
> + if (da_new > da_old) {
> + stolen = XFS_FILBLKS_MIN(da_new - da_old,
> + del->br_blockcount);
> + da_old += stolen;
> + }
> + if (da_new > da_old)
> + xfs_bmap_split_indlen(da_old, &got_indlen, &new_indlen);
> + da_new = got_indlen + new_indlen;
>
> got->br_startblock = nullstartblock((int)got_indlen);
>
> @@ -5007,7 +5002,6 @@ xfs_bmap_del_extent_delay(
> xfs_iext_next(ifp, icur);
> xfs_iext_insert(ip, icur, &new, state);
>
> - da_new = got_indlen + new_indlen - stolen;
> del->br_blockcount -= stolen;
> break;
> }
> --
> 2.39.2
>
>