From: Darrick J. Wong djwong@kernel.org
xfs_bmap_rtalloc initializes the bno_hint variable to NULLRTBLOCK (aka NULLFSBLOCK). If the allocation request is for a file range that's adjacent to an existing mapping, it will then change bno_hint to the blkno hint in the bmalloca structure.
In other words, bno_hint is either a rt block number, or it's all 1s. Unfortunately, commit ec12f97f1b8a8f didn't take the NULLRTBLOCK state into account, which means that it tries to translate that into a realtime extent number. We then end up with an obnoxiously high rtx number and pointlessly feed that to the near allocator. This often fails and falls back to the by-size allocator. Seeing as we had no locality hint anyway, this is a waste of time.
Fix the code to detect a lack of bno_hint correctly. This was detected by running xfs/009 with metadir enabled and a 28k rt extent size.
Cc: stable@vger.kernel.org # v6.12 Fixes: ec12f97f1b8a8f ("xfs: make the rtalloc start hint a xfs_rtblock_t") Signed-off-by: "Darrick J. Wong" djwong@kernel.org --- fs/xfs/xfs_rtalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index 0cb534d71119a5..fcfa6e0eb3ad2a 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -1827,7 +1827,7 @@ xfs_rtallocate_rtg( * For an allocation to an empty file at offset 0, pick an extent that * will space things out in the rt area. */ - if (bno_hint) + if (bno_hint != NULLFSBLOCK) start = xfs_rtb_to_rtx(args.mp, bno_hint); else if (!xfs_has_rtgroups(args.mp) && initial_user_data) start = xfs_rtpick_extent(args.rtg, tp, maxlen);