| From: Jeff Layton <jlayton@redhat.com> |
| Date: Wed, 30 Nov 2016 15:56:46 -0500 |
| Subject: ceph: don't set req->r_locked_dir in ceph_d_revalidate |
| |
| 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", |