Author: kib Date: Sun Sep 22 19:23:48 2013 New Revision: 255797 URL: http://svnweb.freebsd.org/changeset/base/255797
Log: Increase the chance of the buffer write from the bufdaemon helper context to succeed. If the locked vnode which owns the buffer to be written is shared locked, try the non-blocking upgrade of the lock to exclusive. PR: kern/178997 Reported and tested by: Klaus Weber <[email protected]> Sponsored by: The FreeBSD Foundation MFC after: 1 week Approved by: re (marius) Modified: head/sys/kern/vfs_bio.c Modified: head/sys/kern/vfs_bio.c ============================================================================== --- head/sys/kern/vfs_bio.c Sun Sep 22 19:15:24 2013 (r255796) +++ head/sys/kern/vfs_bio.c Sun Sep 22 19:23:48 2013 (r255797) @@ -2624,6 +2624,8 @@ flushbufqueues(struct vnode *lvp, int ta int hasdeps; int flushed; int queue; + int error; + bool unlock; flushed = 0; queue = QUEUE_DIRTY; @@ -2699,7 +2701,16 @@ flushbufqueues(struct vnode *lvp, int ta BUF_UNLOCK(bp); continue; } - if (vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_CANRECURSE) == 0) { + if (lvp == NULL) { + unlock = true; + error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); + } else { + ASSERT_VOP_LOCKED(vp, "getbuf"); + unlock = false; + error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : + vn_lock(vp, LK_UPGRADE | LK_NOWAIT); + } + if (error == 0) { mtx_unlock(&bqdirty); CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); @@ -2711,7 +2722,8 @@ flushbufqueues(struct vnode *lvp, int ta notbufdflushes++; } vn_finished_write(mp); - VOP_UNLOCK(vp, 0); + if (unlock) + VOP_UNLOCK(vp, 0); flushwithdeps += hasdeps; flushed++; _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
