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.
https://git.kernel.org/stable/c/f0d8352a39f4a2e329ae45b71bb0d49e2ca0a6dc
https://git.kernel.org/stable/c/930a9c1c321efdaa3e7f8caecb0479cee3baf342
https://git.kernel.org/stable/c/476582d754cdc5110f806001417fea6c77824c13