The branch main has been updated by bdrewery: URL: https://cgit.FreeBSD.org/src/commit/?id=c926114f2ff20d7c3e5a157f1618b6228f391bf7
commit c926114f2ff20d7c3e5a157f1618b6228f391bf7 Author: Bryan Drewery <[email protected]> AuthorDate: 2021-01-27 17:59:50 +0000 Commit: Bryan Drewery <[email protected]> CommitDate: 2021-01-28 19:24:24 +0000 Fix getblk() with GB_NOCREAT returning false-negatives. It is possible for a buf to be reassigned between the dirty and clean lists while gbincore_unlocked() looks in each list. Avoid creating a buffer in that case and fallback to a locked lookup. This fixes a regression from r363482. More discussion on potential improvements to the clean and dirty lists handling is in the review. Reviewed by: cem, kib, markj, vangyzen, rlibby Reported by: Suraj.Raju at dell.com Submitted by: Suraj.Raju at dell.com, cem, [based on both] MFC after: 2 weeks Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D28375 --- sys/kern/vfs_bio.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 2f18221e9270..ff25e5b0043c 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -3888,8 +3888,15 @@ getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag, /* Attempt lockless lookup first. */ bp = gbincore_unlocked(bo, blkno); - if (bp == NULL) + if (bp == NULL) { + /* + * With GB_NOCREAT we must be sure about not finding the buffer + * as it may have been reassigned during unlocked lookup. + */ + if ((flags & GB_NOCREAT) != 0) + goto loop; goto newbuf_unlocked; + } error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL, "getblku", 0, 0); _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
