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| author | Mateusz Guzik <mjg@FreeBSD.org> | 2021-04-15 07:54:18 +0000 |
|---|---|---|
| committer | Mateusz Guzik <mjg@FreeBSD.org> | 2021-04-21 15:25:32 +0000 |
| commit | 9c651561a2a31fcb08390d37947afc27ec03d87b (patch) | |
| tree | 9a74783d28170864cb2a3c904a64103cd95b08ec /sys | |
| parent | 54f98c4dbf9b1203a4e3e1b13fd0738441226991 (diff) | |
| download | src-9c651561a2a31fcb08390d37947afc27ec03d87b.tar.gz src-9c651561a2a31fcb08390d37947afc27ec03d87b.zip | |
zfs: damage control racing .. lookups in face of mkdir/rmdir
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D29769
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c | 21 |
1 files changed, 21 insertions, 0 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 8172916c4329..a1e9c359b893 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 @@ -781,6 +781,7 @@ zfs_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp, znode_t *zdp = VTOZ(dvp); znode_t *zp; zfsvfs_t *zfsvfs = zdp->z_zfsvfs; + seqc_t dvp_seqc; int error = 0; /* @@ -806,6 +807,8 @@ zfs_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp, ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zdp); + dvp_seqc = vn_seqc_read_any(dvp); + *vpp = NULL; if (flags & LOOKUP_XATTR) { @@ -975,6 +978,24 @@ zfs_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp, } } + if ((cnp->cn_flags & ISDOTDOT) != 0) { + /* + * FIXME: zfs_lookup_lock relocks vnodes and does nothing to + * handle races. In particular different callers may end up + * with different vnodes and will try to add conflicting + * entries to the namecache. + * + * While finding different result may be acceptable in face + * of concurrent modification, adding conflicting entries + * trips over an assert in the namecache. + * + * Ultimately let an entry through once everything settles. + */ + if (!vn_seqc_consistent(dvp, dvp_seqc)) { + cnp->cn_flags &= ~MAKEENTRY; + } + } + /* Insert name into cache (as non-existent) if appropriate. */ if (zfsvfs->z_use_namecache && !zfsvfs->z_replay && error == ENOENT && (cnp->cn_flags & MAKEENTRY) != 0) |