Date: Tue, 28 Apr 2015 22:46:58 +0000 (UTC) From: Steven Hartland <smh@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r282205 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201504282246.t3SMkwVd065269@svn.freebsd.org>
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Author: smh Date: Tue Apr 28 22:46:58 2015 New Revision: 282205 URL: https://svnweb.freebsd.org/changeset/base/282205 Log: Fix misuse of input argument in traverse_visitbp In traverse_visitbp(), the input argument dnp is modified in the middle to point to a temporary buffer. Originally this doesn't matter, because no user of TRAVERSE_POST dereferences it. However, in fbeddd6 a piece of code is added dereferencing dnp after the modification, creating a possible bug. We fix this by creating a new local variable cdnp for the DMU_OT_DNODE case, so we don't modify the input argument. Also we introduce different local variables in the DMU_OT_OBJSET case to prevent confusion between the input argument. Obtained from: zfsonlinux (a585f2f844ed3d4270221fed88f5e494eb55d932) MFC after: 2 weeks Sponsored by: Multiplay Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c Tue Apr 28 22:32:52 2015 (r282204) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c Tue Apr 28 22:46:58 2015 (r282205) @@ -306,21 +306,22 @@ traverse_visitbp(traverse_data_t *td, co arc_flags_t flags = ARC_FLAG_WAIT; int i; int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT; + dnode_phys_t *cdnp; err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf, ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); if (err != 0) goto post; - dnp = buf->b_data; + cdnp = buf->b_data; for (i = 0; i < epb; i++) { - prefetch_dnode_metadata(td, &dnp[i], zb->zb_objset, + prefetch_dnode_metadata(td, &cdnp[i], zb->zb_objset, zb->zb_blkid * epb + i); } /* recursively visitbp() blocks below this */ for (i = 0; i < epb; i++) { - err = traverse_dnode(td, &dnp[i], zb->zb_objset, + err = traverse_dnode(td, &cdnp[i], zb->zb_objset, zb->zb_blkid * epb + i); if (err != 0) break; @@ -328,7 +329,7 @@ traverse_visitbp(traverse_data_t *td, co } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) { arc_flags_t flags = ARC_FLAG_WAIT; objset_phys_t *osp; - dnode_phys_t *dnp; + dnode_phys_t *mdnp, *gdnp, *udnp; err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf, ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); @@ -336,26 +337,27 @@ traverse_visitbp(traverse_data_t *td, co goto post; osp = buf->b_data; - dnp = &osp->os_meta_dnode; - prefetch_dnode_metadata(td, dnp, zb->zb_objset, + mdnp = &osp->os_meta_dnode; + gdnp = &osp->os_groupused_dnode; + udnp = &osp->os_userused_dnode; + + prefetch_dnode_metadata(td, mdnp, zb->zb_objset, DMU_META_DNODE_OBJECT); if (arc_buf_size(buf) >= sizeof (objset_phys_t)) { - prefetch_dnode_metadata(td, &osp->os_groupused_dnode, - zb->zb_objset, DMU_GROUPUSED_OBJECT); - prefetch_dnode_metadata(td, &osp->os_userused_dnode, - zb->zb_objset, DMU_USERUSED_OBJECT); + prefetch_dnode_metadata(td, gdnp, zb->zb_objset, + DMU_GROUPUSED_OBJECT); + prefetch_dnode_metadata(td, udnp, zb->zb_objset, + DMU_USERUSED_OBJECT); } - err = traverse_dnode(td, dnp, zb->zb_objset, + err = traverse_dnode(td, mdnp, zb->zb_objset, DMU_META_DNODE_OBJECT); if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) { - dnp = &osp->os_groupused_dnode; - err = traverse_dnode(td, dnp, zb->zb_objset, + err = traverse_dnode(td, gdnp, zb->zb_objset, DMU_GROUPUSED_OBJECT); } if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) { - dnp = &osp->os_userused_dnode; - err = traverse_dnode(td, dnp, zb->zb_objset, + err = traverse_dnode(td, udnp, zb->zb_objset, DMU_USERUSED_OBJECT); } }
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