add ext2fs-improve-diskfs_node_iterate.patch

2 files changed, 66 insertions, 0 deletions

diff --git a/debian/patches/ext2fs-improve-diskfs_node_iterate.patch b/debian/patches/ext2fs-improve-diskfs_node_iterate.patch
new file mode 100644
index 00000000..7c13875a
--- /dev/null
+++ b/debian/patches/ext2fs-improve-diskfs_node_iterate.patch
@@ -0,0 +1,65 @@
+commit 32b44fe56dab88f63df72bd15b8e0e57be756b2e
+Author: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date:   Tue Apr 29 18:28:22 2014 +0200
+
+    ext2fs: improve diskfs_node_iterate
+    
+    Currently, diskfs_node_iterate iterates twice over all nodes in the
+    cache.  The first time only to determine the number of nodes currently
+    in the cache.  Simply count them instead.
+    
+    * ext2fs/inode.c (nodehash_nr_items): New variable.
+    (diskfs_cached_lookup): Increment nodehash_nr_items.
+    (diskfs_node_norefs): Decrement nodehash_nr_items.
+    (diskfs_node_iterate): Fix the type of num_nodes, use nodehash_nr_items.
+
+diff --git a/ext2fs/inode.c b/ext2fs/inode.c
+index e75c63f..ed78265 100644
+--- a/ext2fs/inode.c
++++ b/ext2fs/inode.c
+@@ -47,6 +47,7 @@
+ #endif
+ 
+ static struct node *nodehash[INOHSZ];
++static size_t nodehash_nr_items;
+ 
+ static error_t read_node (struct node *np);
+ 
+@@ -106,6 +107,7 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+     dn->hnext->dn->hprevp = &dn->hnext;
+   dn->hprevp = &nodehash[INOHASH(inum)];
+   nodehash[INOHASH(inum)] = np;
++  nodehash_nr_items += 1;
+ 
+   pthread_spin_unlock (&diskfs_node_refcnt_lock);
+ 
+@@ -159,6 +161,7 @@ diskfs_node_norefs (struct node *np)
+   *np->dn->hprevp = np->dn->hnext;
+   if (np->dn->hnext)
+     np->dn->hnext->dn->hprevp = np->dn->hprevp;
++  nodehash_nr_items -= 1;
+ 
+   if (np->dn->dirents)
+     free (np->dn->dirents);
+@@ -549,7 +552,8 @@ error_t
+ diskfs_node_iterate (error_t (*fun)(struct node *))
+ {
+   error_t err = 0;
+-  int n, num_nodes = 0;
++  int n;
++  size_t num_nodes;
+   struct node *node, **node_list, **p;
+ 
+   pthread_spin_lock (&diskfs_node_refcnt_lock);
+@@ -559,10 +563,7 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+      during processing (normally we delegate access to hash-table with
+      diskfs_node_refcnt_lock, but we can't hold this while locking the
+      individual node locks).  */
+-
+-  for (n = 0; n < INOHSZ; n++)
+-    for (node = nodehash[n]; node; node = node->dn->hnext)
+-      num_nodes++;
++  num_nodes = nodehash_nr_items;
+ 
+   /* TODO This method doesn't scale beyond a few dozen nodes and should be
+      replaced.  */
diff --git a/debian/patches/series b/debian/patches/series
index cad0ebe1..8662284c 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -45,4 +45,5 @@ ext2fs-two-pagers.patch
 #ext2fs-cache-superblock.patch
 libpager-singlethreaded.patch
 libpager-drop-seqnos.patch
+ext2fs-improve-diskfs_node_iterate.patch
 xxx-fix-build-paper-over-gnumach-bug.patch