Date: Fri, 7 Apr 2023 15:50:34 GMT From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: d012836fb616 - main - zfs: fix up EXDEV handling for clone_range Message-ID: <202304071550.337FoYj8060770@gitrepo.freebsd.org>
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The branch main has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=d012836fb61654942c9d573c8e0f9def598d4ae2 commit d012836fb61654942c9d573c8e0f9def598d4ae2 Author: Mateusz Guzik <mjg@FreeBSD.org> AuthorDate: 2023-04-05 20:27:12 +0000 Commit: Mateusz Guzik <mjg@FreeBSD.org> CommitDate: 2023-04-07 15:46:20 +0000 zfs: fix up EXDEV handling for clone_range API contract requires VOPs to handle EXDEV internally, worst case by falling back to the generic copy routine. This broke with the recent changes. While here whack custom loop to lock 2 vnodes with vn_lock_pair, which provides the same functionality internally. write start/finish around it plays no role so got eliminated. One difference is that vn_lock_pair always takes an exclusive lock on both vnodes. I did not patch around it because current code takes an exclusive lock on the target vnode. zfs supports shared-locking for writes, so this serializes different calls to the routine as is, despite range locking inside. At the same time you may notice the source vnode can get some traffic if only shared-locked, thus once more this goes the safer route of exclusive-locking. Note this should be patched to use shared-locking for both once the feature is considered stable. Technically the switch to vn_lock_pair should be a separate change, but it would only introduce churn immediately whacked by the rest of the patch. [note: technically the review is still in progress, but so is the active breakage] Sponsored by: Rubicon Communications, LLC ("Netgate") --- .../openzfs/module/os/freebsd/zfs/zfs_vnops_os.c | 56 +++++++++++----------- 1 file changed, 27 insertions(+), 29 deletions(-) diff --git a/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c index baa2ee5b3824..67c1a6e3344b 100644 --- a/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c +++ b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c @@ -6250,56 +6250,54 @@ zfs_freebsd_copy_file_range(struct vop_copy_file_range_args *ap) * need something else than vn_generic_copy_file_range(). */ - /* Lock both vnodes, avoiding risk of deadlock. */ - do { - mp = NULL; - error = vn_start_write(outvp, &mp, V_WAIT); - if (error == 0) { - error = vn_lock(outvp, LK_EXCLUSIVE); - if (error == 0) { - if (invp == outvp) - break; - error = vn_lock(invp, LK_SHARED | LK_NOWAIT); - if (error == 0) - break; - VOP_UNLOCK(outvp); - if (mp != NULL) - vn_finished_write(mp); - mp = NULL; - error = vn_lock(invp, LK_SHARED); - if (error == 0) - VOP_UNLOCK(invp); - } + vn_start_write(outvp, &mp, V_WAIT); + if (invp == outvp) { + if (vn_lock(outvp, LK_EXCLUSIVE) != 0) { + goto bad_write_fallback; } - if (mp != NULL) - vn_finished_write(mp); - } while (error == 0); - if (error != 0) - return (error); + } else { + vn_lock_pair(invp, false, outvp, false); + if (VN_IS_DOOMED(invp) || VN_IS_DOOMED(outvp)) { + goto bad_locked_fallback; + } + } + #ifdef MAC error = mac_vnode_check_write(curthread->td_ucred, ap->a_outcred, outvp); if (error != 0) - goto unlock; + goto out_locked; #endif io.uio_offset = *ap->a_outoffp; io.uio_resid = *ap->a_lenp; error = vn_rlimit_fsize(outvp, &io, ap->a_fsizetd); if (error != 0) - goto unlock; + goto out_locked; error = zfs_clone_range(VTOZ(invp), ap->a_inoffp, VTOZ(outvp), ap->a_outoffp, &len, ap->a_outcred); + if (error == EXDEV) + goto bad_locked_fallback; *ap->a_lenp = (size_t)len; - -unlock: +out_locked: if (invp != outvp) VOP_UNLOCK(invp); VOP_UNLOCK(outvp); if (mp != NULL) vn_finished_write(mp); + return (error); +bad_locked_fallback: + if (invp != outvp) + VOP_UNLOCK(invp); + VOP_UNLOCK(outvp); +bad_write_fallback: + if (mp != NULL) + vn_finished_write(mp); + error = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp, + ap->a_outvp, ap->a_outoffp, ap->a_lenp, ap->a_flags, + ap->a_incred, ap->a_outcred, ap->a_fsizetd); return (error); }
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