"Yan, Zheng" <ukernel@xxxxxxxxx> writes:
> On Tue, Jul 10, 2018 at 5:20 AM Luis Henriques <lhenriques@xxxxxxxx> wrote:
>>
>> Chengguang Xu <cgxu519@xxxxxxx> writes:
>>
>> > When file num exceeds quota limit or fails from ceph_per_init_acls()
>> > should call d_drop to drop dentry from cache as well.
>> >
>> > Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
>> > ---
>> > Hello,
>> >
>> > Sorry, I haven't got resource to fully test this patch, so please review.
>>
>> I think this patch isn't correct. In fact, function ceph_mknod seems to
>> be already buggy as it should only call d_drop if dget is also executed
>> (which isn't true if ceph_mdsc_create_request or kstrdup fails).
>>
> why? I think caller (vfs) of ceph_mknod already holds a reference.
Hmm.. Ok, I haven't look too deep but, if that's true, shouldn't the VFS
layer itself be doing the d_drop when ->mknod() returns an error?
ext4_mknod, for example, doesn't do the d_drop.
(Also, in my previous reply I mistakenly referred to a kstrdup failure,
which doesn't exist in ceph_mknod().)
Cheers,
--
Luis
>
>
>> Patch #2 has the same issue, but ceph_symlink does look correct
>> regarding dget/d_drop.
>>
>> Cheers,
>> --
>> Luis
>>
>>
>> >
>> > fs/ceph/dir.c | 18 +++++++++++-------
>> > 1 file changed, 11 insertions(+), 7 deletions(-)
>> >
>> > diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
>> > index 036ac0f3a393..813c01e8ad05 100644
>> > --- a/fs/ceph/dir.c
>> > +++ b/fs/ceph/dir.c
>> > @@ -827,19 +827,21 @@ static int ceph_mknod(struct inode *dir, struct dentry *dentry,
>> > if (ceph_snap(dir) != CEPH_NOSNAP)
>> > return -EROFS;
>> >
>> > - if (ceph_quota_is_max_files_exceeded(dir))
>> > - return -EDQUOT;
>> > + if (ceph_quota_is_max_files_exceeded(dir)) {
>> > + err = -EDQUOT;
>> > + goto out;
>> > + }
>> >
>> > err = ceph_pre_init_acls(dir, &mode, &acls);
>> > if (err < 0)
>> > - return err;
>> > + goto out;
>> >
>> > dout("mknod in dir %p dentry %p mode 0%ho rdev %d\n",
>> > dir, dentry, mode, rdev);
>> > req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
>> > if (IS_ERR(req)) {
>> > err = PTR_ERR(req);
>> > - goto out;
>> > + goto out2;
>> > }
>> > req->r_dentry = dget(dentry);
>> > req->r_num_caps = 2;
>> > @@ -857,12 +859,14 @@ static int ceph_mknod(struct inode *dir, struct dentry *dentry,
>> > if (!err && !req->r_reply_info.head->is_dentry)
>> > err = ceph_handle_notrace_create(dir, dentry);
>> > ceph_mdsc_put_request(req);
>> > -out:
>> > +
>> > if (!err)
>> > ceph_init_inode_acls(d_inode(dentry), &acls);
>> > - else
>> > - d_drop(dentry);
>> > +out2:
>> > ceph_release_acls_info(&acls);
>> > +out:
>> > + if (err)
>> > + d_drop(dentry);
>> > return err;
>> > }
>> --
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