[PATCH 6.7 018/713] ceph: always queue a writeback when revoking the Fb caps

Sasha Levin
2024-03-24T22:47:39Z

From: Xiubo Li <xiubli@redhat.com>

[ Upstream commit 902d6d013f75b68f31d208c6f3ff9cdca82648a7 ]

In case there is 'Fw' dirty caps and 'CHECK_CAPS_FLUSH' is set we
will always ignore queue a writeback. Queue a writeback is very
important because it will block kclient flushing the snapcaps to
MDS and which will block MDS waiting for revoking the 'Fb' caps.

Link: https://tracker.ceph.com/issues/50223
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ceph/caps.c | 48 ++++++++++++++++++++++++------------------------
1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index ad1f46c66fbff..bce3a840f15c2 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2156,6 +2156,30 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags)
ceph_cap_string(cap->implemented),
ceph_cap_string(revoking));

+ /* completed revocation? going down and there are no caps? */
+ if (revoking) {
+ if ((revoking & cap_used) == 0) {
+ doutc(cl, "completed revocation of %s\n",
+ ceph_cap_string(cap->implemented & ~cap->issued));
+ goto ack;
+ }
+
+ /*
+ * If the "i_wrbuffer_ref" was increased by mmap or generic
+ * cache write just before the ceph_check_caps() is called,
+ * the Fb capability revoking will fail this time. Then we
+ * must wait for the BDI's delayed work to flush the dirty
+ * pages and to release the "i_wrbuffer_ref", which will cost
+ * at most 5 seconds. That means the MDS needs to wait at
+ * most 5 seconds to finished the Fb capability's revocation.
+ *
+ * Let's queue a writeback for it.
+ */
+ if (S_ISREG(inode->i_mode) && ci->i_wrbuffer_ref &&
+ (revoking & CEPH_CAP_FILE_BUFFER))
+ queue_writeback = true;
+ }
+
if (cap == ci->i_auth_cap &&
(cap->issued & CEPH_CAP_FILE_WR)) {
/* request larger max_size from MDS? */
@@ -2183,30 +2207,6 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags)
}
}

- /* completed revocation? going down and there are no caps? */
- if (revoking) {
- if ((revoking & cap_used) == 0) {
- doutc(cl, "completed revocation of %s\n",
- ceph_cap_string(cap->implemented & ~cap->issued));
- goto ack;
- }
-
- /*
- * If the "i_wrbuffer_ref" was increased by mmap or generic
- * cache write just before the ceph_check_caps() is called,
- * the Fb capability revoking will fail this time. Then we
- * must wait for the BDI's delayed work to flush the dirty
- * pages and to release the "i_wrbuffer_ref", which will cost
- * at most 5 seconds. That means the MDS needs to wait at
- * most 5 seconds to finished the Fb capability's revocation.
- *
- * Let's queue a writeback for it.
- */
- if (S_ISREG(inode->i_mode) && ci->i_wrbuffer_ref &&
- (revoking & CEPH_CAP_FILE_BUFFER))
- queue_writeback = true;
- }
-
/* want more caps from mds? */
if (want & ~cap->mds_wanted) {
if (want & ~(cap->mds_wanted | cap->issued))
--
2.43.0