3.16.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Jeff Layton jlayton@redhat.com
commit c3f4688a08fd86f1bf8e055724c84b7a40a09733 upstream.
This function sets req->r_locked_dir which is supposed to indicate to ceph_fill_trace that the parent's i_rwsem is locked for write. Unfortunately, there is no guarantee that the dir will be locked when d_revalidate is called, so we really don't want ceph_fill_trace to do any dcache manipulation from this context. Clear req->r_locked_dir since it's clearly not safe to do that.
What we really want to know with d_revalidate is whether the dentry still points to the same inode. ceph_fill_trace installs a pointer to the inode in req->r_target_inode, so we can just compare that to d_inode(dentry) to see if it's the same one after the lookup.
Also, since we aren't generally interested in the parent here, we can switch to using a GETATTR to hint that to the MDS, which also means that we only need to reserve one cap.
Finally, just remove the d_unhashed check. That's really outside the purview of a filesystem's d_revalidate. If the thing became unhashed while we're checking it, then that's up to the VFS to handle anyway.
Fixes: 200fd27c8fa2 ("ceph: use lookup request to revalidate dentry") Link: http://tracker.ceph.com/issues/18041 Reported-by: Donatas Abraitis donatas.abraitis@gmail.com Signed-off-by: Jeff Layton jlayton@redhat.com Reviewed-by: "Yan, Zheng" zyan@redhat.com Signed-off-by: Ilya Dryomov idryomov@gmail.com Cc: Bryan Henderson bryanh@giraffe-data.com [bwh: Backported to 3.16: s/d_really_is_(positive|negative)/d_is_\1/ since we don't have to consider overlayfs] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/ceph/dir.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)
--- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -1071,26 +1071,30 @@ static int ceph_d_revalidate(struct dent int op, mask, err;
op = ceph_snap(dir) == CEPH_SNAPDIR ? - CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP; + CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_GETATTR; req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS); if (!IS_ERR(req)) { req->r_dentry = dget(dentry); - req->r_num_caps = 2; + req->r_num_caps = op == CEPH_MDS_OP_GETATTR ? 1 : 2;
mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED; if (ceph_security_xattr_wanted(dir)) mask |= CEPH_CAP_XATTR_SHARED; req->r_args.getattr.mask = mask;
- req->r_locked_dir = dir; err = ceph_mdsc_do_request(mdsc, NULL, req); - if (err == 0 || err == -ENOENT) { - if (dentry == req->r_dentry) { - valid = !d_unhashed(dentry); - } else { - d_invalidate(req->r_dentry); - err = -EAGAIN; - } + switch (err) { + case 0: + if (d_is_positive(dentry) && + d_inode(dentry) == req->r_target_inode) + valid = 1; + break; + case -ENOENT: + if (d_is_negative(dentry)) + valid = 1; + /* Fallthrough */ + default: + break; } ceph_mdsc_put_request(req); dout("d_revalidate %p lookup result=%d\n",