ceph: introduce an inode flag to indicates if snapflush is needed

Signed-off-by: Yan, Zheng <zyan@redhat.com>

3 files changed, 36 insertions, 15 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index f12d59d26a04..45fe7a3658dc 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1368,6 +1368,7 @@ static void ceph_flush_snaps(struct ceph_inode_info *ci)
 {
         spin_lock(&ci->i_ceph_lock);
         __ceph_flush_snaps(ci, NULL);
+        ci->i_ceph_flags &= ~CEPH_I_FLUSH_SNAPS;
         spin_unlock(&ci->i_ceph_lock);
 }
 
@@ -1563,8 +1564,10 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
                 flags |= CHECK_CAPS_FLUSH;
 
         /* flush snaps first time around only */
-        if (!list_empty(&ci->i_cap_snaps))
+        if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS) {
                 __ceph_flush_snaps(ci, &session);
+                ci->i_ceph_flags &= ~CEPH_I_FLUSH_SNAPS;
+        }
         goto retry_locked;
 retry:
         spin_lock(&ci->i_ceph_lock);
@@ -2498,7 +2501,8 @@ void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps)
  * drop cap_snap that is not associated with any snapshot.
  * we don't need to send FLUSHSNAP message for it.
  */
-static int ceph_try_drop_cap_snap(struct ceph_cap_snap *capsnap)
+static int ceph_try_drop_cap_snap(struct ceph_inode_info *ci,
+                                  struct ceph_cap_snap *capsnap)
 {
         if (!capsnap->need_flush &&
             !capsnap->writing && !capsnap->dirty_pages) {
@@ -2506,6 +2510,9 @@ static int ceph_try_drop_cap_snap(struct ceph_cap_snap *capsnap)
                      capsnap, capsnap->follows);
                 BUG_ON(capsnap->cap_flush.tid > 0);
                 ceph_put_snap_context(capsnap->context);
+                if (!list_is_last(&capsnap->ci_item, &ci->i_cap_snaps))
+                        ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
+
                 list_del(&capsnap->ci_item);
                 ceph_put_cap_snap(capsnap);
                 return 1;
@@ -2553,7 +2560,7 @@ void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
                                                         struct ceph_cap_snap,
                                                         ci_item);
                                 capsnap->writing = 0;
-                                if (ceph_try_drop_cap_snap(capsnap))
+                                if (ceph_try_drop_cap_snap(ci, capsnap))
                                         put++;
                                 else if (__ceph_finish_cap_snap(ci, capsnap))
                                         flushsnaps = 1;
@@ -2596,15 +2603,19 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
                                 struct ceph_snap_context *snapc)
 {
         struct inode *inode = &ci->vfs_inode;
-        int last = 0;
-        int complete_capsnap = 0;
-        int drop_capsnap = 0;
-        int found = 0;
         struct ceph_cap_snap *capsnap = NULL;
+        int put = 0;
+        bool last = false;
+        bool found = false;
+        bool flush_snaps = false;
+        bool complete_capsnap = false;
 
         spin_lock(&ci->i_ceph_lock);
         ci->i_wrbuffer_ref -= nr;
-        last = !ci->i_wrbuffer_ref;
+        if (ci->i_wrbuffer_ref == 0) {
+                last = true;
+                put++;
+        }
 
         if (ci->i_head_snapc == snapc) {
                 ci->i_wrbuffer_ref_head -= nr;
@@ -2624,15 +2635,22 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
         } else {
                 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
                         if (capsnap->context == snapc) {
-                                found = 1;
+                                found = true;
                                 break;
                         }
                 }
                 BUG_ON(!found);
                 capsnap->dirty_pages -= nr;
                 if (capsnap->dirty_pages == 0) {
-                        complete_capsnap = 1;
-                        drop_capsnap = ceph_try_drop_cap_snap(capsnap);
+                        complete_capsnap = true;
+                        if (!capsnap->writing) {
+                                if (ceph_try_drop_cap_snap(ci, capsnap)) {
+                                        put++;
+                                } else {
+                                        ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
+                                        flush_snaps = true;
+                                }
+                        }
                 }
                 dout("put_wrbuffer_cap_refs on %p cap_snap %p "
                      " snap %lld %d/%d -> %d/%d %s%s\n",
@@ -2647,12 +2665,12 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
 
         if (last) {
                 ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
-                iput(inode);
-        } else if (complete_capsnap) {
+        } else if (flush_snaps) {
                 ceph_flush_snaps(ci);
-                wake_up_all(&ci->i_cap_wq);
         }
-        if (drop_capsnap)
+        if (complete_capsnap)
+                wake_up_all(&ci->i_cap_wq);
+        while (put-- > 0)
                 iput(inode);
 }
 
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 20d5b0cdf655..c3b03ae1976c 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -601,6 +601,8 @@ int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
                      capsnap->dirty_pages);
                 return 0;
         }
+
+        ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
         dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
              inode, capsnap, capsnap->context,
              capsnap->context->seq, ceph_cap_string(capsnap->dirty),
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 16068787afb4..63fdb57606fe 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -469,6 +469,7 @@ static inline struct inode *ceph_find_inode(struct super_block *sb,
 #define CEPH_I_SEC_INITED       (1 << 7)  /* security initialized */
 #define CEPH_I_CAP_DROPPED      (1 << 8)  /* caps were forcibly dropped */
 #define CEPH_I_KICK_FLUSH       (1 << 9)  /* kick flushing caps */
+#define CEPH_I_FLUSH_SNAPS      (1 << 10) /* need flush snapss */
 
 static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
                                            long long release_count,