On Fri, 21 Feb 2025, Viacheslav Dubeyko wrote:
> On Fri, 2025-02-21 at 10:36 +1100, NeilBrown wrote:
> > ceph already splices the correct dentry (in splice_dentry()) from the
> > result of mkdir but does nothing more with it.
> >
> > Now that ->mkdir can return a dentry, return the correct dentry.
> >
> > Signed-off-by: NeilBrown <neilb@xxxxxxx>
> > ---
> > fs/ceph/dir.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> > index 39e0f240de06..c1a1c168bb27 100644
> > --- a/fs/ceph/dir.c
> > +++ b/fs/ceph/dir.c
> > @@ -1099,6 +1099,7 @@ static struct dentry *ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
> > struct ceph_client *cl = mdsc->fsc->client;
> > struct ceph_mds_request *req;
> > struct ceph_acl_sec_ctx as_ctx = {};
> > + struct dentry *ret = NULL;
>
> I believe that it makes sense to initialize pointer by error here and always
> return ret as output. If something goes wrong in the logic, then we already have
> error.
I'm not certain that I understand, but I have made a change which seems
to be consistent with the above and included it below. Please let me
know if it is what you intended.
>
> > int err;
> > int op;
> >
> > @@ -1166,14 +1167,20 @@ static struct dentry *ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
> > !req->r_reply_info.head->is_dentry)
> > err = ceph_handle_notrace_create(dir, dentry);
> > out_req:
> > + if (!err && req->r_dentry != dentry)
> > + /* Some other dentry was spliced in */
> > + ret = dget(req->r_dentry);
> > ceph_mdsc_put_request(req);
> > out:
> > if (!err)
> > + /* Should this use 'ret' ?? */
>
> Could we make a decision should or shouldn't? :)
> It looks not good to leave this comment instead of proper implementation. Do we
> have some obstacles to make this decision?
I suspect we should use ret, but I didn't want to make a change which
wasn't directly required by my needed. So I highlighted this which
looks to me like a possible bug, hoping that someone more familiar with
the code would give an opinion. Do you agree that 'ret' (i.e.
->r_dentry) should be used when ret is not NULL?
>
> > ceph_init_inode_acls(d_inode(dentry), &as_ctx);
> > else
> > d_drop(dentry);
> > ceph_release_acl_sec_ctx(&as_ctx);
> > - return ERR_PTR(err);
> > + if (err)
> > + return ERR_PTR(err);
> > + return ret;
>
> What's about this?
>
> return err ? ERR_PTR(err) : ret;
We could do that, but you said above that you thought we should always
return 'ret' - which does make some sense.
What do you think of the following alternate patch?
Thanks,
NeilBrown
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 39e0f240de06..d2e5c557df83 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1099,6 +1099,7 @@ static struct dentry *ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
struct ceph_client *cl = mdsc->fsc->client;
struct ceph_mds_request *req;
struct ceph_acl_sec_ctx as_ctx = {};
+ struct dentry *ret;
int err;
int op;
@@ -1116,32 +1117,32 @@ static struct dentry *ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
ceph_vinop(dir), dentry, dentry, mode);
op = CEPH_MDS_OP_MKDIR;
} else {
- err = -EROFS;
+ ret = ERR_PTR(-EROFS);
goto out;
}
if (op == CEPH_MDS_OP_MKDIR &&
ceph_quota_is_max_files_exceeded(dir)) {
- err = -EDQUOT;
+ ret = ERR_PTR(-EDQUOT);
goto out;
}
if ((op == CEPH_MDS_OP_MKSNAP) && IS_ENCRYPTED(dir) &&
!fscrypt_has_encryption_key(dir)) {
- err = -ENOKEY;
+ ret = ERR_PTR(-ENOKEY);
goto out;
}
req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
if (IS_ERR(req)) {
- err = PTR_ERR(req);
+ ret = ERR_CAST(req);
goto out;
}
mode |= S_IFDIR;
req->r_new_inode = ceph_new_inode(dir, dentry, &mode, &as_ctx);
if (IS_ERR(req->r_new_inode)) {
- err = PTR_ERR(req->r_new_inode);
+ ret = ERR_CAST(req->r_new_inode);
req->r_new_inode = NULL;
goto out_req;
}
@@ -1165,15 +1166,23 @@ static struct dentry *ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
!req->r_reply_info.head->is_target &&
!req->r_reply_info.head->is_dentry)
err = ceph_handle_notrace_create(dir, dentry);
+ ret = ERR_PTR(err);
out_req:
+ if (!IS_ERR(ret) && req->r_dentry != dentry)
+ /* Some other dentry was spliced in */
+ ret = dget(req->r_dentry);
ceph_mdsc_put_request(req);
out:
- if (!err)
- ceph_init_inode_acls(d_inode(dentry), &as_ctx);
- else
+ if (!IS_ERR(ret)) {
+ if (ret)
+ ceph_init_inode_acls(d_inode(ret), &as_ctx);
+ else
+ ceph_init_inode_acls(d_inode(dentry), &as_ctx);
+ } else {
d_drop(dentry);
+ }
ceph_release_acl_sec_ctx(&as_ctx);
- return ERR_PTR(err);
+ return ret;
}
static int ceph_link(struct dentry *old_dentry, struct inode *dir,
