Date: Sat, 12 Dec 2009 23:52:21 +0000 (UTC) From: Kip Macy <kmacy@FreeBSD.org> To: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: svn commit: r200457 - user/kmacy/releng_8_fcs_buf_xen/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <200912122352.nBCNqLg0067591@svn.freebsd.org>
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Author: kmacy Date: Sat Dec 12 23:52:20 2009 New Revision: 200457 URL: http://svn.freebsd.org/changeset/base/200457 Log: add comment clarifying call to zbio_sync_cache Modified: user/kmacy/releng_8_fcs_buf_xen/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Modified: user/kmacy/releng_8_fcs_buf_xen/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c ============================================================================== --- user/kmacy/releng_8_fcs_buf_xen/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Sat Dec 12 23:47:31 2009 (r200456) +++ user/kmacy/releng_8_fcs_buf_xen/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Sat Dec 12 23:52:20 2009 (r200457) @@ -435,10 +435,15 @@ zio_create(zio_t *pio, spa_t *spa, uint6 else zio->io_child_type = ZIO_CHILD_LOGICAL; - if (bp != NULL) { io_bypass = 0; + /* + * Synchronize buffer with page cache - making sure that + * the page cache only holds the most recent txg's pages. + * This also allows us to skip disk I/O if we hit in the + * page cache. + */ if (((vd == NULL) || (vd->vdev_parent == NULL)) && ((type == ZIO_TYPE_WRITE) || (type == ZIO_TYPE_READ))) io_bypass = zbio_sync_cache(spa, bp, txg, data, size,
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