knfsd: exportfs: add find_disconnected_root helper

Break the loop that finds the root of a disconnected subtree into a helper of
its own to make reading easier and document the intent.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 085d6c5..166d8ca 100644 (file)
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -70,6 +70,27 @@ find_acceptable_alias(struct dentry *result,
        return NULL;
 }
 
+/*
+ * Find root of a disconnected subtree and return a reference to it.
+ */
+static struct dentry *
+find_disconnected_root(struct dentry *dentry)
+{
+       dget(dentry);
+       spin_lock(&dentry->d_lock);
+       while (!IS_ROOT(dentry) &&
+              (dentry->d_parent->d_flags & DCACHE_DISCONNECTED)) {
+               struct dentry *parent = dentry->d_parent;
+               dget(parent);
+               spin_unlock(&dentry->d_lock);
+               dput(dentry);
+               dentry = parent;
+               spin_lock(&dentry->d_lock);
+       }
+       spin_unlock(&dentry->d_lock);
+       return dentry;
+}
+
 /**
  * find_exported_dentry - helper routine to implement export_operations->decode_fh
  * @sb:                The &super_block identifying the filesystem
@@ -164,23 +185,9 @@ find_exported_dentry(struct super_block *sb, void *obj, void *parent,
         * the noprogress counter.  If we go through the loop 10 times (2 is
         * probably enough) without getting anywhere, we just give up
         */
-       noprogress= 0;
+       noprogress = 0;
        while (target_dir->d_flags & DCACHE_DISCONNECTED && noprogress++ < 10) {
-               struct dentry *pd = target_dir;
-
-               dget(pd);
-               spin_lock(&pd->d_lock);
-               while (!IS_ROOT(pd) &&
-                               (pd->d_parent->d_flags&DCACHE_DISCONNECTED)) {
-                       struct dentry *parent = pd->d_parent;
-
-                       dget(parent);
-                       spin_unlock(&pd->d_lock);
-                       dput(pd);
-                       pd = parent;
-                       spin_lock(&pd->d_lock);
-               }
-               spin_unlock(&pd->d_lock);
+               struct dentry *pd = find_disconnected_root(target_dir);
 
                if (!IS_ROOT(pd)) {
                        /* must have found a connected parent - great */