ceph: introduce ceph_fill_fragtree()

Move the code that update the i_fragtree into a separate function.
Also add simple probabilistic test to decide whether the i_fragtree
should be updated

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 8ad50a3..850b26d 100644 (file)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -10,6 +10,7 @@
 #include <linux/writeback.h>
 #include <linux/vmalloc.h>
 #include <linux/posix_acl.h>
+#include <linux/random.h>
 
 #include "super.h"
 #include "mds_client.h"
@@ -179,9 +180,8 @@ struct ceph_inode_frag *__ceph_find_frag(struct ceph_inode_info *ci, u32 f)
  * specified, copy the frag delegation info to the caller if
  * it is present.
  */
-u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
-                    struct ceph_inode_frag *pfrag,
-                    int *found)
+static u32 __ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
+                             struct ceph_inode_frag *pfrag, int *found)
 {
        u32 t = ceph_frag_make(0, 0);
        struct ceph_inode_frag *frag;
@@ -191,7 +191,6 @@ u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
        if (found)
                *found = 0;
 
-       mutex_lock(&ci->i_fragtree_mutex);
        while (1) {
                WARN_ON(!ceph_frag_contains_value(t, v));
                frag = __ceph_find_frag(ci, t);
@@ -220,10 +219,19 @@ u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
        }
        dout("choose_frag(%x) = %x\n", v, t);
 
-       mutex_unlock(&ci->i_fragtree_mutex);
        return t;
 }
 
+u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
+                    struct ceph_inode_frag *pfrag, int *found)
+{
+       u32 ret;
+       mutex_lock(&ci->i_fragtree_mutex);
+       ret = __ceph_choose_frag(ci, v, pfrag, found);
+       mutex_unlock(&ci->i_fragtree_mutex);
+       return ret;
+}
+
 /*
  * Process dirfrag (delegation) info from the mds.  Include leaf
  * fragment in tree ONLY if ndist > 0.  Otherwise, only
@@ -286,6 +294,75 @@ out:
        return err;
 }
 
+static int ceph_fill_fragtree(struct inode *inode,
+                             struct ceph_frag_tree_head *fragtree,
+                             struct ceph_mds_reply_dirfrag *dirinfo)
+{
+       struct ceph_inode_info *ci = ceph_inode(inode);
+       struct ceph_inode_frag *frag;
+       struct rb_node *rb_node;
+       int i;
+       u32 id, nsplits;
+       bool update = false;
+
+       mutex_lock(&ci->i_fragtree_mutex);
+       nsplits = le32_to_cpu(fragtree->nsplits);
+       if (nsplits) {
+               i = prandom_u32() % nsplits;
+               id = le32_to_cpu(fragtree->splits[i].frag);
+               if (!__ceph_find_frag(ci, id))
+                       update = true;
+       } else if (!RB_EMPTY_ROOT(&ci->i_fragtree)) {
+               rb_node = rb_first(&ci->i_fragtree);
+               frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+               if (frag->frag != ceph_frag_make(0, 0) || rb_next(rb_node))
+                       update = true;
+       }
+       if (!update && dirinfo) {
+               id = le32_to_cpu(dirinfo->frag);
+               if (id != __ceph_choose_frag(ci, id, NULL, NULL))
+                       update = true;
+       }
+       if (!update)
+               goto out_unlock;
+
+       dout("fill_fragtree %llx.%llx\n", ceph_vinop(inode));
+       rb_node = rb_first(&ci->i_fragtree);
+       for (i = 0; i < nsplits; i++) {
+               id = le32_to_cpu(fragtree->splits[i].frag);
+               frag = NULL;
+               while (rb_node) {
+                       frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+                       if (ceph_frag_compare(frag->frag, id) >= 0) {
+                               if (frag->frag != id)
+                                       frag = NULL;
+                               else
+                                       rb_node = rb_next(rb_node);
+                               break;
+                       }
+                       rb_node = rb_next(rb_node);
+                       rb_erase(&frag->node, &ci->i_fragtree);
+                       kfree(frag);
+                       frag = NULL;
+               }
+               if (!frag) {
+                       frag = __get_or_create_frag(ci, id);
+                       if (IS_ERR(frag))
+                               continue;
+               }
+               frag->split_by = le32_to_cpu(fragtree->splits[i].by);
+               dout(" frag %x split by %d\n", frag->frag, frag->split_by);
+       }
+       while (rb_node) {
+               frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+               rb_node = rb_next(rb_node);
+               rb_erase(&frag->node, &ci->i_fragtree);
+               kfree(frag);
+       }
+out_unlock:
+       mutex_unlock(&ci->i_fragtree_mutex);
+       return 0;
+}
 
 /*
  * initialize a newly allocated inode.
@@ -584,12 +661,8 @@ static int fill_inode(struct inode *inode,
        struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
        struct ceph_mds_reply_inode *info = iinfo->in;
        struct ceph_inode_info *ci = ceph_inode(inode);
-       int i;
        int issued = 0, implemented, new_issued;
        struct timespec mtime, atime, ctime;
-       u32 nsplits;
-       struct ceph_inode_frag *frag;
-       struct rb_node *rb_node;
        struct ceph_buffer *xattr_blob = NULL;
        struct ceph_cap *new_cap = NULL;
        int err = 0;
@@ -804,42 +877,8 @@ static int fill_inode(struct inode *inode,
                ceph_queue_vmtruncate(inode);
 
        /* populate frag tree */
-       /* FIXME: move me up, if/when version reflects fragtree changes */
-       nsplits = le32_to_cpu(info->fragtree.nsplits);
-       mutex_lock(&ci->i_fragtree_mutex);
-       rb_node = rb_first(&ci->i_fragtree);
-       for (i = 0; i < nsplits; i++) {
-               u32 id = le32_to_cpu(info->fragtree.splits[i].frag);
-               frag = NULL;
-               while (rb_node) {
-                       frag = rb_entry(rb_node, struct ceph_inode_frag, node);
-                       if (ceph_frag_compare(frag->frag, id) >= 0) {
-                               if (frag->frag != id)
-                                       frag = NULL;
-                               else
-                                       rb_node = rb_next(rb_node);
-                               break;
-                       }
-                       rb_node = rb_next(rb_node);
-                       rb_erase(&frag->node, &ci->i_fragtree);
-                       kfree(frag);
-                       frag = NULL;
-               }
-               if (!frag) {
-                       frag = __get_or_create_frag(ci, id);
-                       if (IS_ERR(frag))
-                               continue;
-               }
-               frag->split_by = le32_to_cpu(info->fragtree.splits[i].by);
-               dout(" frag %x split by %d\n", frag->frag, frag->split_by);
-       }
-       while (rb_node) {
-               frag = rb_entry(rb_node, struct ceph_inode_frag, node);
-               rb_node = rb_next(rb_node);
-               rb_erase(&frag->node, &ci->i_fragtree);
-               kfree(frag);
-       }
-       mutex_unlock(&ci->i_fragtree_mutex);
+       if (S_ISDIR(inode->i_mode))
+               ceph_fill_fragtree(inode, &info->fragtree, dirinfo);
 
        /* update delegation info? */
        if (dirinfo)