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>

1 files changed, 84 insertions, 45 deletions

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 8ad50a30808e..850b26d2e601 100644
--- 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)