CVE-2026-98446

In the Linux kernel, the following vulnerability has been resolved:

xfs: don't let hidden_space go negative in xfs_metafile_resv_init

LOLLM points out that if the amount of fdblocks that we can reserve for

a metadata btree file goes below the space already used by that file,

then the hidden_space subtraction can underflow, causing

xfs_dec_fdblocks to subtract a huge amount of space. We never want the

target to be less than the used sapce, so fix the logic that adjusts

dblocks_avail downwards.

Also fix an error in the adjacent comment.