On 07/23/2013 01:25 PM, Sage Weil wrote:
> On Tue, 23 Jul 2013, Yan, Zheng wrote:
>> On 07/23/2013 09:41 AM, Sage Weil wrote:
>>> On Sun, 21 Jul 2013, Yan, Zheng wrote:
>>>> From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
>>>>
>>>> The MDS uses caps message to notify clients about deleted inode.
>>>> when receiving a such message, invalidate any alias of the inode.
>>>> This makes the kernel release the inode ASAP.
>>>>
>>>> Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
>>>> ---
>>>> fs/ceph/caps.c | 31 ++++++++++++++++++++++++++++++-
>>>> 1 file changed, 30 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
>>>> index 25442b4..b446fdd 100644
>>>> --- a/fs/ceph/caps.c
>>>> +++ b/fs/ceph/caps.c
>>>> @@ -2334,6 +2334,28 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
>>>> }
>>>>
>>>> /*
>>>> + * Invalidate unlinked inode's aliases, so we can drop the inode
>>>> + * from the cache ASAP.
>>>> + */
>>>> +static void invalidate_aliases(struct inode *inode)
>>>> +{
>>>> + struct dentry *dn;
>>>> +
>>>> + dout("invalidate_aliases inode %p\n", inode);
>>>> + d_prune_aliases(inode);
>>>> + while ((dn = d_find_alias(inode))) {
>>>> + d_delete(dn);
>>>> + dput(dn);
>>>
>>> I don't think this loop is safe. d_delete() won't unlink the inode if
>>> there are other refs to the dentry, which would make this get stuck in a
>>> loop. Maybe simple checking if we get the same dentry back from
>>> d_find_alias() as the previous call?
>>>
>>
>> For non-dir inode, d_find_alias() only return connected dentry. After calling
>> d_delete, the dentry become disconnected. so the loop is safe.
>
> Oh, right. Totally misread that.
>
>>>> + /*
>>>> + * for dir inode, d_find_alias() can return
>>>> + * disconnected dentry
>>>> + */
>>>> + if (S_ISDIR(inode->i_mode))
>>>> + break;
>>>> + }
>>>
>>> If we handle the more general case, I'm not sure we need any special case
>>> here for the directory... although I confess I'm not sure why disconnected
>>> dentries should be treated specially at all.
>>>
>>
>> For dir inode, d_find_alias() may disconnected dentry, that's why the special case
>> is needed. how about below code.
>
> Right. I think either variation is okay. I'll pull in the original for
> now, unless you prefer the below. Sorry for the runaround!
>
> sage
>
please apply the attached version, thanks.
Yan, Zheng
>From 04e85337b3384e7be52a0aefb6ae63491986be7d Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
Date: Sun, 21 Jul 2013 10:07:51 +0800
Subject: [PATCH] ceph: trim deleted inode
The MDS uses caps message to notify clients about deleted inode.
when receiving a such message, invalidate any alias of the inode.
This makes the kernel release the inode ASAP.
Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
---
fs/ceph/caps.c | 41 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 40 insertions(+), 1 deletion(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 25442b4..430121a 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2334,6 +2334,38 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
}
/*
+ * Invalidate unlinked inode's aliases, so we can drop the inode ASAP.
+ */
+static void invalidate_aliases(struct inode *inode)
+{
+ struct dentry *dn, *prev = NULL;
+
+ dout("invalidate_aliases inode %p\n", inode);
+ d_prune_aliases(inode);
+ /*
+ * For non-directory inode, d_find_alias() only returns
+ * connected dentry. After calling d_delete(), the dentry
+ * become disconnected.
+ *
+ * For directory inode, d_find_alias() only can return
+ * disconnected dentry. But directory inode should have
+ * one alias at most.
+ */
+ while ((dn = d_find_alias(inode))) {
+ if (dn == prev) {
+ dput(dn);
+ break;
+ }
+ d_delete(dn);
+ if (prev)
+ dput(prev);
+ prev = dn;
+ }
+ if (prev)
+ dput(prev);
+}
+
+/*
* Handle a cap GRANT message from the MDS. (Note that a GRANT may
* actually be a revocation if it specifies a smaller cap set.)
*
@@ -2363,6 +2395,7 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
int writeback = 0;
int revoked_rdcache = 0;
int queue_invalidate = 0;
+ int deleted_inode = 0;
dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
inode, cap, mds, seq, ceph_cap_string(newcaps));
@@ -2407,8 +2440,12 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
from_kgid(&init_user_ns, inode->i_gid));
}
- if ((issued & CEPH_CAP_LINK_EXCL) == 0)
+ if ((issued & CEPH_CAP_LINK_EXCL) == 0) {
set_nlink(inode, le32_to_cpu(grant->nlink));
+ if (inode->i_nlink == 0 &&
+ (newcaps & (CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL)))
+ deleted_inode = 1;
+ }
if ((issued & CEPH_CAP_XATTR_EXCL) == 0 && grant->xattr_len) {
int len = le32_to_cpu(grant->xattr_len);
@@ -2517,6 +2554,8 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
ceph_queue_writeback(inode);
if (queue_invalidate)
ceph_queue_invalidate(inode);
+ if (deleted_inode)
+ invalidate_aliases(inode);
if (wake)
wake_up_all(&ci->i_cap_wq);
--
1.8.1.4
