On 10/11/2022 21:48, Ilya Dryomov wrote:
On Thu, Nov 10, 2022 at 2:02 PM <xiubli@xxxxxxxxxx> wrote:
From: Xiubo Li <xiubli@xxxxxxxxxx>
The request's r_session maybe changed when it was forwarded or
resent. Both the forwarding and resending cases the requests will
be protected by the mdsc->mutex.
Cc: stable@xxxxxxxxxxxxxxx
URL: https://bugzilla.redhat.com/show_bug.cgi?id=2137955
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
Changed in V5:
- simplify the code by removing the "unlikely(s->s_mds >= max_sessions)" check.
Changed in V4:
- move mdsc->mutex acquisition and max_sessions assignment into "if (req1 || req2)" branch
fs/ceph/caps.c | 48 ++++++++++++------------------------------------
1 file changed, 12 insertions(+), 36 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 894adfb4a092..065e9311b607 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2297,7 +2297,6 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode)
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_request *req1 = NULL, *req2 = NULL;
- unsigned int max_sessions;
int ret, err = 0;
spin_lock(&ci->i_unsafe_lock);
@@ -2315,28 +2314,24 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode)
}
spin_unlock(&ci->i_unsafe_lock);
- /*
- * The mdsc->max_sessions is unlikely to be changed
- * mostly, here we will retry it by reallocating the
- * sessions array memory to get rid of the mdsc->mutex
- * lock.
- */
-retry:
- max_sessions = mdsc->max_sessions;
-
/*
* Trigger to flush the journal logs in all the relevant MDSes
* manually, or in the worst case we must wait at most 5 seconds
* to wait the journal logs to be flushed by the MDSes periodically.
*/
- if ((req1 || req2) && likely(max_sessions)) {
- struct ceph_mds_session **sessions = NULL;
- struct ceph_mds_session *s;
+ if (req1 || req2) {
struct ceph_mds_request *req;
+ struct ceph_mds_session **sessions;
+ struct ceph_mds_session *s;
+ unsigned int max_sessions;
int i;
+ mutex_lock(&mdsc->mutex);
+ max_sessions = mdsc->max_sessions;
+
sessions = kcalloc(max_sessions, sizeof(s), GFP_KERNEL);
if (!sessions) {
+ mutex_unlock(&mdsc->mutex);
err = -ENOMEM;
goto out;
}
@@ -2348,16 +2343,6 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode)
s = req->r_session;
if (!s)
continue;
- if (unlikely(s->s_mds >= max_sessions)) {
- spin_unlock(&ci->i_unsafe_lock);
- for (i = 0; i < max_sessions; i++) {
- s = sessions[i];
- if (s)
- ceph_put_mds_session(s);
- }
- kfree(sessions);
- goto retry;
- }
if (!sessions[s->s_mds]) {
s = ceph_get_mds_session(s);
sessions[s->s_mds] = s;
@@ -2370,16 +2355,6 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode)
s = req->r_session;
if (!s)
continue;
- if (unlikely(s->s_mds >= max_sessions)) {
- spin_unlock(&ci->i_unsafe_lock);
- for (i = 0; i < max_sessions; i++) {
- s = sessions[i];
- if (s)
- ceph_put_mds_session(s);
- }
- kfree(sessions);
- goto retry;
- }
if (!sessions[s->s_mds]) {
s = ceph_get_mds_session(s);
sessions[s->s_mds] = s;
@@ -2391,11 +2366,12 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode)
/* the auth MDS */
spin_lock(&ci->i_ceph_lock);
if (ci->i_auth_cap) {
- s = ci->i_auth_cap->session;
- if (!sessions[s->s_mds])
- sessions[s->s_mds] = ceph_get_mds_session(s);
+ s = ci->i_auth_cap->session;
+ if (!sessions[s->s_mds])
+ sessions[s->s_mds] = ceph_get_mds_session(s);
}
spin_unlock(&ci->i_ceph_lock);
+ mutex_unlock(&mdsc->mutex);
/* send flush mdlog request to MDSes */
for (i = 0; i < max_sessions; i++) {
--
2.31.1
Reviewed-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Thanks Ilya!
- Xiubo
Thanks,
Ilya
