[PATCH] exportfs: add find_acceptable_alias helper

find_exported_dentry contains two duplicate loops to find an alias that the
acceptable callback likes.  Split this out to a new helper and switch from
list_for_each to list_for_each_entry to make it more readable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 36 insertions, 43 deletions

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 5bfe40085fbc..b06b54f1bbbb 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -11,6 +11,33 @@ struct export_operations export_op_default;
 
 #define dprintk(fmt, args...) do{}while(0)
 
+static struct dentry *
+find_acceptable_alias(struct dentry *result,
+                int (*acceptable)(void *context, struct dentry *dentry),
+                void *context)
+{
+        struct dentry *dentry, *toput = NULL;
+
+        spin_lock(&dcache_lock);
+        list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) {
+                dget_locked(dentry);
+                spin_unlock(&dcache_lock);
+                if (toput)
+                        dput(toput);
+                if (dentry != result && acceptable(context, dentry)) {
+                        dput(result);
+                        return dentry;
+                }
+                spin_lock(&dcache_lock);
+                toput = dentry;
+        }
+        spin_unlock(&dcache_lock);
+
+        if (toput)
+                dput(toput);
+        return NULL;
+}
+
 /**
  * find_exported_dentry - helper routine to implement export_operations->decode_fh
  * @sb:         The &super_block identifying the filesystem
@@ -52,8 +79,7 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
         struct dentry *target_dir;
         int err;
         struct export_operations *nops = sb->s_export_op;
-        struct list_head *le, *head;
-        struct dentry *toput = NULL;
+        struct dentry *alias;
         int noprogress;
         char nbuf[NAME_MAX+1];
 
@@ -79,27 +105,10 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
                         /* there is no other dentry, so fail */
                         goto err_result;
                 }
-                /* try any other aliases */
-                spin_lock(&dcache_lock);
-                head = &result->d_inode->i_dentry;
-                list_for_each(le, head) {
-                        struct dentry *dentry = list_entry(le, struct dentry, d_alias);
-                        dget_locked(dentry);
-                        spin_unlock(&dcache_lock);
-                        if (toput)
-                                dput(toput);
-                        toput = NULL;
-                        if (dentry != result &&
-                            acceptable(context, dentry)) {
-                                dput(result);
-                                return dentry;
-                        }
-                        spin_lock(&dcache_lock);
-                        toput = dentry;
-                }
-                spin_unlock(&dcache_lock);
-                if (toput)
-                        dput(toput);
+
+                alias = find_acceptable_alias(result, acceptable, context);
+                if (alias)
+                        return alias;
         }                       
 
         /* It's a directory, or we are required to confirm the file's
@@ -258,26 +267,10 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
         /* now result is properly connected, it is our best bet */
         if (acceptable(context, result))
                 return result;
-        /* one last try of the aliases.. */
-        spin_lock(&dcache_lock);
-        toput = NULL;
-        head = &result->d_inode->i_dentry;
-        list_for_each(le, head) {
-                struct dentry *dentry = list_entry(le, struct dentry, d_alias);
-                dget_locked(dentry);
-                spin_unlock(&dcache_lock);
-                if (toput) dput(toput);
-                if (dentry != result &&
-                    acceptable(context, dentry)) {
-                        dput(result);
-                        return dentry;
-                }
-                spin_lock(&dcache_lock);
-                toput = dentry;
-        }
-        spin_unlock(&dcache_lock);
-        if (toput)
-                dput(toput);
+
+        alias = find_acceptable_alias(result, acceptable, context);
+        if (alias)
+                return alias;
 
         /* drat - I just cannot find anything acceptable */
         dput(result);