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

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

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index f12d59d..45fe7a3 100644 (file)
--- 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 20d5b0c..c3b03ae 100644 (file)
--- 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 1606878..63fdb57 100644 (file)
--- 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,