xfs: correct the parent pointer space reservation comment

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The comment on xfs_parent_calc_space_res() claims parent pointers are
"always the first attr in an attr tree".  They are not: a parent pointer
is recorded per dirent, so by the Nth hardlink the attr fork is already
in leaf or node format.  The reservation is still correct, because
XFS_DAENTER_SPACE_RES() covers a split at every level of a maximum-depth
attr dabtree whatever format the fork is in, but anyone auditing a
shortfall here is led by the comment to look for a bug that is not
there.

Rewrite the comment to state what actually bounds the result, and record
why the double split allowance and the extent-add term differ from
xfs_attr_calc_size().

Signed-off-by: Javier Tia <floss@jetm.me>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

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Javier Tia 2026-08-10 17:06:16 -06:00 • committed by Carlos Maiolino

parent d058f24b16

commit 6c0fc3cb4e

1 changed files with 17 additions and 2 deletions

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fs/xfs/libxfs/xfs_trans_space.c

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